View allAll Photos Tagged hypocenter
Seen here is one month's worth of earthquakes (mid-January to mid-February 2022) along the San Andreas Fault in California, USA (the city of San Francisco is beyond the upper left margin of the map). Magnitudes ranged from 0.1 to 3.1. The San Andreas is the most famous fault zone in the world. It is a transform plate boundary, along which the Pacific Plate (to the west) and the North American Plate (to the east) slide past each other. Despite the term "slide", movement is usually not slow and smooth and gradual - tectonic movement is usually in the form of sudden jolts, which send out shockwaves, resulting in earthquakes. Major quakes occasionally occur along the San Andreas Fault (for example, in 1906 and 1989).
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See info. at:
en.wikipedia.org/wiki/San_Andreas_Fault
and
en.wikipedia.org/wiki/1906_San_Francisco_earthquake
and
en.wikipedia.org/wiki/1989_Loma_Prieta_earthquake
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
The appearance of the present Hiroshima-shi. Neighborhood of center is the hypocenter. It has become the memorial park now.
The noise on the 21:00 line on this seismogram from the Blue Mountains Array seismic station in Oregon represents shock waves from a magnitude 5.1 earthquake that occurred offshore from Oregon, USA. The quake hit at 12:15 PM, local time, on 20 February 2021. The epicenter was located in the Cascadia Canyon, 294 kilometers due west of the town of Lakeside, Oregon. Movement was right-lateral slip along a nearly vertically-oriented fault that strikes west-northwest to south-southeast.
The quake occurred east of the Cascadia Depression, along the Blanco Transform Fault (often mis-referred to as the Blanco Fracture Zone - fracture zones are extensions of transform faults away from mid-ocean ridges). The Blanco Transform Fault is the boundary between the Juan de Fuca Plate and the Pacific Plate, along which transform plate movement occurs. Transform plate boundaries involve two tectonic plates sliding past each other, usually in the form of sudden jolts.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000djrl/exec...
and
en.wikipedia.org/wiki/Blanco_Fracture_Zone
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
About the only remnant besides the dome in the area that still gives evidence of that day are the nearby tombstones behind Saiko Temple 西向寺 near the hypocenter. The tombstones have been roughened by the 3000°C+ heat (lower melting point minerals liquified leaving higher temperature minerals sticking out). A small hospital stood at this location, but both doctors had left the city on house calls. 巡り合わせ -
This seismogram is from the Ankara seismic station in Turkey. The noise is from a magnitude 7.8 earthquake that hit southern Turkey at 4:17 AM, local time, on 6 February 2023. The epicenter was just east of the town of Atalar and northwest of Bayatli in southern Turkey. The hypocenter was between 15 and 20 kilometers deep. Shaking resulted from left-lateral strike-slip movement along a northeast-southwest trending fault zone. This is the fourth magnitude 7+ earthquake of 2023. The quake occurred during a Moon-Earth-Sun alignment.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000jllz/exec...
[An event-specific summary is at the bottom of that page.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This map of part of eastern California is from the United States Geological Survey's Earthquake Hazards Program. It shows a 7 day epicenter cluster for earthquakes in the Little Antelope Valley area near the California-Nevada border. The largest circle near the center of the cluster is a 6.0 quake that occurred at 3:49 PM, local tme, on 8 July 2021 (see: www.flickr.com/photos/jsjgeology/51301425133 ). All other epicenters are aftershocks, starting less than a minute after the main shock. Over 1,100 aftershock events occurred in the following 7 days. Aftershocks that follow large earthquakes can continue for months to years or even decades. (Update: as of 28 July 2021, there have been over 2,100 aftershocks.)
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Greenback seismic station in Tennessee, USA. The noise was caused by a magnitude 2.5 earthquake that occurred in eastern Tennessee at 1:44 AM, local time, on 8 December 2021. The epicenter was about 13 kilometers south-southeast of Knoxville, Tennessee. The hypocenter was about 9 kilometers deep.
Earthquakes in eastern America are uncommon and usually small to moderate in magnitude, while strong quakes are rare. This earthquake occurred in the Appalachian Mountains, in the Valley and Ridge Physiographic Province. The area principally consists of folded sedimentary rocks. The Appalachians formed by tectonic collision between Africa and North America during the Pennsylvanian Period. Numerous faults occur throughout the mountains and the modern stress field causes some of them to move occasionally, producing earthquakes.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/se60365472/exec...
and
en.wikipedia.org/wiki/Eastern_Tennessee_seismic_zone
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This map (provided by the United States Geological Survey) shows the location of a magnitude 7.0 offshore earthquake that hit the Vanuatu archipelago (= southwestern Pacific Ocean) at 11:32 PM, local time, on 8 January 2023. The epicenter was in Big Bay, offshore from Espiritu Santo Island, Vanuatu. The hypocenter was between 25 and 30 kilometers deep. This is the first magnitude 7+ earthquake of 2023.
This quake was caused by reverse faulting in a subduction zone setting. Subduction zones have tectonic plates composed of oceanic lithosphere diving underneath another tectonic plate. In this case, the Australian Plate is subducting ~eastward beneath the New Hebrides Plate along a deep seafloor trough called the North New Hebrides Trench.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000j2yw/exec...
[An event-specific summary is at the bottom of that webpage.]
and
en.wikipedia.org/wiki/New_Hebrides_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Willy Bob seismic station on Barbuda Island in the Caribbean. The noise represents shock waves from a magnitude 6.8 earthquake that hit just offshore from Honshu Island, Japan at 10:27 AM, local time, on 1 May 2021. The quake's magnitude has been assigned values ranging from 6.6 to 6.9 by different seismic reporting agencies. The epicenter was about 40 kilometers southeast of the town of Ishinomaki, Japan. The hypocenter was at about 47 kilometers depth.
This was a subduction zone earthquake. Subduction zones have tectonic plates composed of oceanic lithosphere diving beneath another tectonic plate. In this case, the Pacific Plate is subducting ~westward under the Okhotsk Plate along the Japan Trench.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000dz5t/exec...
and
en.wikipedia.org/wiki/Japan_Trench
and
en.wikipedia.org/wiki/Okhotsk_Plate
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Adak station in Alaska. The black scribble was caused by shock waves from a powerful, magnitude 8.2 earthquake that hit offshore from the Alaska Peninsula. The quake occurred at 10:15 PM, local time, on 28 July 2021. The epicenter was about 81 kilometers southeast of Mitrofania Island. The hypocenter was between 30 and 35 kilometers deep. A tsunami less than 1 foot high was generated by the quake - it affected a limited portion of the Pacific Basin.
This was a subduction zone earthquake, involving movement along a thrust fault of low dip. Subduction zones have one tectonic plate composed of oceanic lithosphere diving beneath a plate of continental or oceanic lithosphere. In this case, the oceanic Pacific Plate is subducting beneath continental lithosphere of the North American Plate. Subduction zones have the most powerful tectonic quakes in the world. Quakes and volcanism are common geologic hazards in such settings. The subduction zone itself is a deep seafloor trough next to the Alaska Peninsula and the Aleutian Islands chain - the Alaska-Aleutians Trench. Active and potentially active volcanoes occur throughout this part of Alaska.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/ak0219neiszm/ex...
and
www.volcanodiscovery.com/earthquakes/6343344/2021-07-29/0...
and
en.wikipedia.org/wiki/Aleutian_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram for the Kislovodsk seismic station in far-southwestern Russia . The noise on the 15:00 line (click on the image once or twice to zoom in) was caused by shock waves from a magnitude 5.1 earthquake that occurred just north of Lake Sevan in Armenia at 10:36 AM, local time, on 5 February 2021. The hypocenter was at about 9 kilometers depth.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000detl/exec...
and
earthquake.usgs.gov/earthquakes/eventpage/us6000detl/regi... [Scroll down for a tectonic summary of the Middle East region.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
These are seismograms for the Maple Creek and Parker Peak seismic stations in Yellowstone, Wyoming. The prominent noise on the 21:00 lines (click on the image once or twice to zoom in) was caused by shock waves from a magnitude 4.5 earthquake that hit the southeastern Mackenzie Mountains in northwestern Canada. The quake occurred at 9:05 PM, local time, on 24 July 2020. Shock waves arrived at the seismic stations at 9:09 PM, Yellowstone time, a little over 4 minutes after the quake hit.
The Mackenzie Mountains are part of a very long mountain chain called the Cordillera. The Alpine-Himalayan Belt in the Old World and the Cordillera are the two longest mountain chains on Earth. The Cordillera is along the western margin of the New World - it consists of Alaskan mountains, the Canadian Rockies, the American Rockies, Central American mountains, and the Andes of South America. Most of the chain is relatively young, geologically - late Mesozoic to Cenozoic. Much of the Cordillera formed by subduction, but other tectonic processes have also played a role (collisions of small blocks, translational tectonics, and extensional tectonics).
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000b3ul/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Semarang seismic station on the island of Java in Indonesia. The prominent blue noise was caused by a magnitude 5.6 earthquake in western Java at 1:21 PM, local time, on 21 November 2022. The epicenter was on the eastern side of Mount Gede, a subduction zone stratovolcano. Shaking resulted from strike-slip movement along an ~east-west or ~north-south trending, vertical to subvertical fault zone.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000ir9t/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Naypyitaw seismic station in Burma. The red noise was caused by a magnitude 5.7 earthquake that hit far-northern Laos in southeastern Asia. The quake occurred at 9:43 PM, local time, on 24 December 2021. Movement was right-lateral slip along a ~northwest-southeast striking fault or left-lateral slip along a northeast-southwest striking fault.
The blue noise is a magnitude 4.6 aftershock that hit the same area about 19 minutes later.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000gf1y/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Modbury Heights seismic station in South Australia. The prominent noise represents shock waves from a magnitude 5.3 earthquake that occurred in Western Australia. The quake hit at 9:05 PM, local time, on 13 November 2021. The epicenter was along Walgunya Creek in the northern part of Western Australia, about 102 kilometers south of the "town" of Pardoo.
Strong earthquakes in Australia are uncommon. This one resulted from strike-slip movement along a very steeply-dipping fault.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000fttj/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Gun Hill seismic station on Barbados. The black scribble is from a powerful magnitude 7.3 earthquake that hit offshore Timor Island in Indonesia, which is nearly antipodal to the station. The quake occurred at 3:25 AM, local time, on 30 December 2021. The epicenter was between Romang Island and Maopora Island, north-northeast of the easternmost tip of Timor. The hypocenter was about 167 kilometers deep. Movement was the result of somewhat oblique reverse faulting. The fault zone strikes ~east-west or ~northwest-southeast.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000g7lx/exec...
[An event-specific summary is at the bottom of that webpage.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram for the Maple Creek seismic station in Yellowstone, Wyoming. The prominent noise on the 22:00 line (click on the image once or twice to zoom in) was caused by shock waves from a magnitude 5.6 earthquake that hit south-southwest of Umnak Island, offshore from the Aleutian Islands, Alaska. The quake occurred at 7:12 PM, local time, on 26 September 2020. Shock waves arrived at the seismic station at 10:19 PM, Yellowstone time, ~7 minutes after the quake hit. The hypocenter area was almost 14 kilometers deep.
This was a subduction zone earthquake. Subduction zones have a tectonic plate composed of oceanic lithosphere diving underneath a plate of continental or oceanic lithosphere. In this case, the oceanic Pacific Plate is subducting beneath continental lithosphere of the North American Plate. Subduction zones have the most powerful tectonic quakes in the world. Quakes and volcanism are common geologic hazards in such settings. The subduction zone itself is a deep seafloor trough next to the Alaska Peninsula and the Aleutian Islands chain - the Alaska-Aleutians Trench. Active and potentially active volcanoes occur throughout this part of Alaska.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000c1tj/exec...
and
en.wikipedia.org/wiki/Aleutian_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Kansas State University seismic station south of Manhattan, Kansas, USA. The noise was caused by a magnitude 4.0 earthquake that occurred in east-central Kansas at 3:58 AM, local time, on 15 December 2021. The epicenter was about 3 kilometers south-southwest of the town of Gypsum, Kansas. The hypocenter was about 3 kilometers deep.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000gcd6/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This map shows a cluster of over 660 earthquake events that occurred from 15 July to 28 July 2021 in central Yellowstone Lake, Wyoming, USA. The most powerful events were magnitude 3.0, 3.1, 3.2, and 3.6. Clusters of earthquakes are called "swarms". Frequent activity started at about 9:00 PM, local time, on 15 July 2021. Most of the earthquakes occurred north of Frank Island. (Update: as of 31 July 2021, about 830 quakes occurred in this swarm.)
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Campanas Astronomical Observatory seismic station in Chile. The prominent scribble is from a magnitude 7.5 earthquake that hit northern Peru at 5:52 AM, local time, on 28 November 2021. The epicenter was about 64 kilometers ~east of the town of Porvenir, Peru. The hypocenter was between 120 and 130 kilometers depth, a moderate depth.
This quake was the result of normal faulting along a north-northwest to south-southeast striking fault within deeply-subducted oceanic lithosphere of the Nazca Plate.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000fxq2/exec... [A write-up of the quake is at the bottom of that page.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
中国軍管区司令部 地下通信室跡 flic.kr/p/eyzF87
広島市中区基町 広島城址公園
Underground communication room of Chugoku Regional Military Headquarters
Remains of Chugoku Military District Headquarters
Hiroshima castle ruins park, Moto-machi, Naka-ku, Hiroshima
Roughly 800 meters from the hypocenter
photozou.jp/photo/show/2140645/178859840
Yoshie Oka, a third-year student from the Hijiyama Girls High School (then, 14) was exposed to the bomb inside the Chugoku Military District Headquarters Air Defense Room while at work. Yoshie relayed the terrible fate of Hiroshima to military personnel in Fukuyama using a military phone that had managed to escape damage. This is considered the first report of the atomic bombing of Hiroshima.
史跡 広島城 広島城址公園 広島市中区基町
二の丸表御門 www.panoramio.com/photo/91215463
Hiroshima castle second bailey (ninomaru) main gate flic.kr/p/eyyyaS
被爆樹木 ユーカリ A-Bombed tree Eucalyptus flic.kr/p/eyyNub
被爆樹木 マルバヤナギ A-Bombed tree Japanese pussy willow flic.kr/p/eyvMz2
本丸跡 石垣 central bailey honmaru, stone walls flic.kr/p/eyz1QS
中国軍管区司令部 地下通信室跡
Underground communication room of Chugoku Regional Military Headquarters
Remains of Chugoku Military District Headquarters
広島大本営跡 被爆樹木 クロガネモチ A-Bombed tree Kurogane holly
flic.kr/p/eywnpg flic.kr/p/eyzyrU flic.kr/p/eywtKp
広島大本営跡 ruins of Imperial Headquarters in Hiroshima www.panoramio.com/photo/91153347 flic.kr/p/eyvYF6
広島城 Hiroshima Castle www.panoramio.com/photo/87561876 www.panoramio.com/photo/87561876 flic.kr/p/ez16gp
広島護国神社 Hiroshima Gokoku Shrine www.panoramio.com/photo/91105666 flic.kr/p/eyuTqp
神馬 sacred horse www.panoramio.com/photo/91105689 flic.kr/p/eyuTtM
This seismogram is from the Soe seismic station on Timor Island. The prominent red noise represents shock waves from two powerful, closely-spaced earthquakes that hit offshore from Honshu Island, Japan. The first quake was a magnitude 6.0 foreshock that occurred at 11:34 PM, local time, on 16 March 2022. The second quake was a magnitude 7.3 main shock - it occurred at 11:36 PM, a little over 2 minutes later. The main shock's epicenter was about 88 kilometers southeast of the town of Sendai, Japan. The hypocenter was between 60 and 65 kilometers deep.
These were subduction zone earthquakes. A subduction zone consists of one tectonic plate composed of oceanic lithosphere diving underneath another tectonic plate. In this case, the Pacific Plate is subducting ~westward under the Okhotsk Plate along the Japan Trench.
This was the first magnitude 7+ earthquake of 2022. It occurred during a Moon-Earth-Sun alignment.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000h518/exec...
and
earthquake.usgs.gov/earthquakes/eventpage/us6000h519/exec...
and
en.wikipedia.org/wiki/Japan_Trench
and
en.wikipedia.org/wiki/Okhotsk_Plate
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
Shigeko Sasamori was 14 years old when the bomb exploded on August 6, 1945 in Hiroshima. Although she was two miles away from the hypocenter and sustained extensive burns, she survived. On this April day in Oberlin, she shares her story with students in Professor of Japanese Ann Sherif’s course, Living with the Bomb.
Photo by Michael Hartman
This is a seismogram from the Pohakuloa seismic station on Hawaii. The noise on the 5:00 line was caused by a magnitude 6.2 earthquake that occurred below the southeastern Pacific Ocean seafloor at 9:40 PM, local time, on 2 December 2021. The epicenter was ~320 kilometers west-southwest of Easter Island. Movement was strike-slip motion along a ~vertically-oriented transform fault. The quake occurred along the East Pacific Rise, a major spreading center or mid-ocean ridge where tectonic divergence occurs - two plates composed of oceanic lithosphere move away from each other and new basaltic crust forms. In this case, the Pacific Plate and the Nazca Plate are diverging. This earthquake hit along a segment of the East Pacific Rise between the Easter Microplate (to the north) and the Juan Fernandez Microplate (to the south).
The quake occurred during an Earth-Moon-Sun alignment.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000g8md/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram for the Parker Peak seismic station in Yellowstone, Wyoming. The prominent noise on the 22:00 line was caused by shock waves from a magnitude 4.9 earthquake that hit western Nevada at 9:15 PM, local time, on 2 December 2020. The shock waves first arrived at the seismic station at 10:17 PM, Yellowstone time, 2 to 2.5 minutes after the quake hit. The United States Geological Survey reports that the earthquake's hypocenter was at 5 kilometers depth. The epicenter was at 38° 10' 30" North latitude, 118° 03' 54" West longitude, which is in the Candelaria Hills, home of the Candelaria Mining District. Silver mines have operated intermittently in the area since the 1800s.
Nevada has numerous faults that border its mountain ranges (horsts) and extensive valleys (grabens). This region of North America, referred to as the Basin and Range Physiographic Province, has experienced significant crustal extension throughout the Cenozoic Era.
This event was part of ongoing seismic swarm activity in western Nevada. A more powerful earthquake hit the same area 1 day earlier, on 1 December 2020 (see: www.flickr.com/photos/jsjgeology/50671214186 ).
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
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See info. at:
earthquake.usgs.gov/earthquakes/eventpage/nn00788443/exec...
This seismogram is from the Mammoth seismic station in eastern California. The noise is from a magnitude 3.9 earthquake that hit the eastern edge of California's Sierra Nevada Mountains. The quake occurred at 7:05 PM, local time, on 30 March 2022. The epicenter was in Round Valley, just northeast of Mount Tom and just northwest of the Tungsten Hills. Shaking resulted from right-lateral slip along a northwest-southeast striking fault zone, or left-lateral slip along a northeast-southwest striking fault zone.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/nc73712486/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the South Karori seismic station in New Zealand. The noise was caused by a magnitude 6.9 offshore earthquake that hit the Kermadec Trench area in the southwestern Pacific Ocean. The quake occurred at 7:41 PM, local time, on 4 March 2023. The epicenter was about 91 kilometers north-northwest of Macauley Island in the Kermadec Islands. The hypocenter was about 205 kilometers deep ("intermediate depth"). Shaking resulted from oblique normal faulting along a northeast-southwest striking fault zone or a north-northwest to south-southeast striking fault zone.
--------------------------------
Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000jh99/exec...
and
en.wikipedia.org/wiki/Kermadec_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Castle Rocks seismic station in Alaska. The noise is from a magnitude 4.1 earthquake that hit the Alaska Range. The quake occurred at 10:08 AM, local time, on 7 February 2022. The epicenter was a little northwest of the northern end of Chelatna Lake, west of the Kahiltna Glacier. The hypocenter was over 90 kilometers deep.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/ak0221r5s6b4/ex...
--------------------------------
An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Lakeview Retreat seismic station in Alabama, USA. The noise was caused by a magnitude 3.1 earthquake that occurred in central Alabama at 12:20 AM, local time, on 22 December 2021. The epicenter was about 10 kilometers east of the town of Maplesville, Alabama.
Earthquakes in eastern America are uncommon and usually small to moderate in magnitude, while strong quakes are rare.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/se60140943/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Vandalia seismic station in Illinois, USA. The noise was caused by a magnitude 2.4 earthquake that occurred in southern Illinois at 11:45 AM, local time, on 19 December 2021. The epicenter was about 3.5 kilometers east of the town of Junction City, Illinois. The hypocenter was between 12 and 13 kilometers deep.
Earthquakes in eastern America are uncommon and usually small to moderate in magnitude, while strong quakes are rare.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/nm60377471/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
The noise on this seismogram from the Shade River State Forest seismic station in Meigs County, southeastern Ohio, USA represents shock waves from a powerful magnitude 7.7 earthquake that occurred in the New Hebrides Trench in the southwestern Pacific Ocean. Nearby major islands and archipelagos include New Caledonia, the Loyalty Islands, Vanuatu, and Fiji. The main shock hit at 12:19 AM, local time, on 11 February 2021. The epicenter was about 112 kilometers south-southwest of Hunter Island and 379 kilometers south-southeast of Anatom Island. The hypocenter was between 25 and 26 kilometers deep. Many strong aftershocks in the 5s and 6s occurred afterward.
Signal noise on the diagram that precedes the 7.7 quake is from one or more strong earthquakes that occurred in the previous hour: 6.0 and 6.1 foreshock events in the New Hebrides Trench and a 6.2 quake in Indonesia.
This was a global event - significant noise was recorded at every functioning seismic station I've looked at.
This was a subduction zone earthquake. Subduction zones have tectonic plates composed of oceanic lithosphere diving underneath another tectonic plate. In this case, the Australian Plate is subducting beneath the Pacific Plate.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000dg77/exec... [Scroll down to read event-specific and general tectonic summaries.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
Hiroshima Atomic Bomb Dome ("Gembaku Domu" in Japanese), next to the Aioi river, one of five or six rivers in the city.
The building's original name was the Industrial Promotion Hall, and it was considerably larger than the remains left after the explosion (the Peace Museum has a model of the building before the blast). It was one of the few buildings left standing within a two kilometer (one and a quarter mile) radius of the explosion. It's remarkable that anything of the building survived at all, because it's estimated that the shock wave from the bomb created a pressure of 35 tons per square meter at the hypocenter.
This is a seismogram from the Kiritimati Island, Kiribati seismic station in the central Pacific Ocean. The prominent noise was caused by a magnitude 6.5 offshore earthquake that hit east of the Kermadec Islands, in the southwestern Pacific Ocean. The quake occurred at 2:46 PM, local time, on 28 January 2022. Shaking resulted from thrust faulting along a NNE-SSW striking fault zone.
This was a subduction zone earthquake. Subduction zones involve one tectonic plate composed of oceanic lithosphere diving underneath another tectonic plate. In this case, the Pacific Plate is subducting ~westward beneath the Australian Plate. The surface expression of the subduction zone is a deep seafloor trough called the Kermadec Trench.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000gg3w/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Kipapa seismic station in Hawaii. The prominent noise was caused by shock waves from a magnitude 6.7 earthquake that occurred below the southeastern Pacific Ocean seafloor at 5:42 PM, local time, on 18 May 2021. Various seismic reporting agencies have assigned magnitude values ranging from 6.2 to 6.7. The epicenter was ~662 kilometers due south of Easter Island. Movement was strike-slip motion along a ~vertically-oriented transform fault. The quake occurred at or near the eastern margin of the Juan Fernandez Plate, a microplate at the Pacific-Nazca-Antarctic triple junction, just east of the East Pacific Rise.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000e4aw/exec...
and
en.wikipedia.org/wiki/Juan_Fernández_Plate
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Santo Domingo seismic station in Venezuela. The noise is from a magnitude 6.8 earthquake that hit coastal Ecuador at 12:12 PM, local time, on 18 March 2023. The epicenter was on the eastern side of the Jambelí Channel, between Puná Island and mainland Ecuador. The hypocenter was between 65 and 70 kilometers deep.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000jl3s/exec...
[An event-specific summary is at the bottom of that page.]
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Borganes station in Iceland. The noise represents over a dozen offshore earthquakes that hit the Reykjanes Ridge southwest of Iceland from 31 July to 1 August 2021. The largest event was a magnitude 5.2 quake. The five smaller events were magnitude 4.6 to 4.8. The smallest areas of noise are microquakes.
The Reykjanes Ridge is part of the Mid-Atlantic Ridge, the classic example of a mid-ocean ridge, where two tectonic plates diverge (separate) and new oceanic crust forms. This is called "seafloor spreading". In this case, the North American Plate is moving away from the Eurasian Plate.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000f17k/exec...
and
en.wikipedia.org/wiki/Mid-Atlantic_Ridge
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the T25A seismic station near Trinidad, Colorado, USA. The noise was caused by a magnitude 4.3 earthquake in the Rocky Mountains of southern Colorado. The quake occurred at 11:06 PM, local time, on 9 March 2023. The epicenter was north of Burro Canyon in the Sangre de Cristo Range, about 9 kilometers northwest of the town of Cokedale, Colorado. The hypocenter was about 6 kilometers below sea level. Shaking resulted from normal faulting along a northeast-southwest striking fault zone.
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Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000jiqv/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This map (provided by the United States Geological Survey) shows the locations of 48 offshore earthquakes in the South New Hebrides Trench area, south of the Vanuatu Archipelago (= southwestern Pacific Ocean). The series started with a main shock of magnitude 7.7 at 1:57 PM, local time, on 19 May 2023 (= large yellow dot on the map). Forty-seven significant aftershocks occurred during the following day, the most powerful of which were a magnitude 7.1 event 23 hours later and a magnitude 6.5 event 19 minutes after that. Twenty-seven aftershocks were in the 5s, and the remainder ranged from 4.6 to 4.9. Additional events will occur.
This earthquake series occurred in a flexure zone next to an oceanic trench. Trenches form at subduction zones, where tectonic plates composed of oceanic lithosphere dive underneath other tectonic plates. In this case, the Australian Plate is subducting beneath the Pacific Plate along a deep seafloor trough called the New Hebrides Trench (a.k.a. South New Hebrides Trench).
The series commenced during an Earth-Moon-Sun alignment.
--------------------------------
Info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000kd0n/exec...
[An event-specific summary is at the bottom of that webpage.]
--------------------------------
An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram for the Parker Peak seismic station in Yellowstone, Wyoming. The cluster of earthquake events in the middle and bottom parts of the graph occurred on 10 September 2020 south of Yellowstone Lake's West Thumb. Quake magnitudes ranged from 0.1 to 2.8. Activity continued the following day. Clusters of earthquakes are called "swarms".
Update: a total of 114 earthquakes occurred.
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
These are seismograms for the Maple Creek and Parker Peak seismic stations in Yellowstone, Wyoming. The noise on left side of the 18:30 lines was caused by shock waves from a magnitude 4.9 earthquake in California, USA. It occurred at the town of Westmorland, just southeast of the Salton Sea and north of the American-Mexican border. The quake hit at 5:31 PM, local time, on 30 September 2020. Seismic waves arrived at the seismic stations about 3 minutes later. The hypocenter was about 11.5 kilometers deep. Hundreds of aftershocks followed this event.
The Westmorland, California area is known as the Brawley Seismic Zone, a small region of extensional tectonics between two transform faults: the San Andreas Fault to the north and the Imperial Fault to the south. This is an unusual example of a mid-ocean ridge on land. The extensional area and transform faults are part of the mid-ocean ridge system in the Gulf of California, in Mexico.
The second, larger quake seen here, on the right side of the 19:00 lines on the charts, is a magnitude 6.4 event in the Tonga Islands, north of New Zealand in the Pacific Ocean. This earthquake occurred at 2:13 PM, local time, on 1 October 2020. Seismic waves arrived at the stations ~13 minutes later. The hypocenter was about 35 kilometers deep.
This was a subduction zone earthquake, produced where one tectonic plate dives beneath another. Subduction zones have the most powerful tectonic quakes in the world. They also contain active and potentially active volcanoes that have explosive eruptions. Examples of subduction zones include Japan, the Philippines, Indonesia, the Andes, the Aleutian Islands of Alaska, and the Cascade Range in America's Pacific Northwest.
Subduction zones are expressed as deep troughs on the seafloor called trenches. In this case, the quake occurred along the Tonga Trench.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/ci39641528/exec...
and
en.wikipedia.org/wiki/Brawley_Seismic_Zone
and
earthquake.usgs.gov/earthquakes/eventpage/us6000c3kz/exec...
and
earthquake.usgs.gov/earthquakes/eventpage/us6000c3kz/regi... [scroll down to see a write-up of the tectonics of the area]
and
en.wikipedia.org/wiki/Tonga_Trench
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This is a seismogram from the Guam seismic station in the Mariana Islands. The prominent noise was caused by a magnitude 6.6 offshore earthquake that hit the Kermadec Trench area in the southwestern Pacific Ocean. The quake occurred at 12:52 AM, local time, on 2 March 2022. The epicenter was about 67 kilometers east-northeast of Macauley Island. The hypocenter was about 36 kilometers deep. Shaking resulted from thrust faulting along a NNE-SSW striking fault zone.
This was a subduction zone earthquake. Subduction zones involve one tectonic plate composed of oceanic lithosphere diving underneath another tectonic plate. In this case, the Pacific Plate is subducting ~westward beneath the Australian Plate. The surface expression of the subduction zone is a deep seafloor trough called the Kermadec Trench.
This quake occurred during an Earth-Moon-Sun alignment.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us6000h1d2/exec...
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
This seismogram is from the Bilibino seismic station in Russia. The prominent noise is from a magnitude 6.2 offshore earthquake that occurred in the Aleutian Islands area of Alaska. The quake hit at 8:17 PM, local time, on 21 January 2022. The epicenter was about 14 kilometers south of Unalaska Island's Cape Prominence. The hypocenter was between 40 and 45 kilometers deep. Shaking resulted from thrust faulting along an ENE-WSW striking fault zone.
The Aleutian Islands are an extensive volcanic arc formed along a subduction zone, where one tectonic plate dives beneath another. In this case, oceanic lithosphere of the Pacific Plate is subducting below the North American Plate. Earthquakes and volcanism are common along such plate boundaries. The surface expression of the subduction zone is a deep seafloor trough called the Aleutian Trench.
See info. at:
earthquake.usgs.gov/earthquakes/eventpage/us7000ge5q/exec...
and
en.wikipedia.org/wiki/Aleutian_Trench
and
en.wikipedia.org/wiki/Aleutian_Arc
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.
Sumako Fukuda Poetry Memorial, Nagasaki Peace Park. Sumako Fukuda wrote numerous well-known poems carrying humanitarian and peace messages responding to the devastation of the bombing / Nagasaki Peace Park is a park located in Nagasaki, Japan, commemorating the atomic bombing of the city on August 9, 1945 during World War II. Nagasaki Peace Park is built on a low hill to the north of the hypocenter of the atomic bomb blast. It was created to represent the wish for world peace and a vow that such a tragic war would never be repeated. The park features the 9.7-meter-high Peace Statue symbolizing the Nagasaki citizens' wish for peace by Sculptor Seibou Kitamura, a Nagasaki native. In 1978 the city of Nagasaki established a "Peace Symbols Zone" on both sides of the park and invited donations of monuments from countries round the world.
This is a seismogram for the Upper Falls seismic station in Yellowstone, Wyoming. The station is at the Grand Canyon of the Yellowstone River. The noise at the bottom of the graph (click on the image to zoom in) was caused by shock waves from a magnitude 7.1 earthquake that hit southern California at 8:19 PM, local time, on 5 July 2019. The shock waves first arrived at the seismic station at about 9:24 PM, Yellowstone time, which is 5 minutes after the quake hit. The United States Geological Survey reports that the earthquake's hypocenter was at 17 kilometers depth. The epicenter is at 35° 45' 58" North latitude, 117° 36' 18" West longitude. This is between Death Valley and the Mojave Block, an area of California that has numerous faults.
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An earthquake is a natural shaking or vibrating of the Earth caused by sudden fault movement and a rapid release of energy. Earthquake activity is called "seismicity". The study of earthquakes is called "seismology". The actual underground location of an earthquake is the hypocenter, or focus. The site at the Earth's surface, directly above the hypocenter, is the epicenter. Minor earthquakes may occur before a major event - such small quakes are called foreshocks. Minor to major quakes after a major event are aftershocks.
Most earthquakes occur at or near tectonic plate boundaries, such as subduction zones, mid-ocean ridges, collision zones, and transform plate boundaries. They also occur at hotspots - large subsurface mantle plumes (Examples: Hawaii, Yellowstone, Iceland, Afar).
Earthquakes generate four types of shock waves: P-waves, S-waves, Love waves, and Rayleigh waves. P-waves and S-waves are body waves - they travel through solid rocks. Love waves and Rayleigh waves travel only at the surface - they are surface waves. P-waves are push-pull waves that travel quickly and cause little damage. S-waves are up-and-down waves (like flicking a rope) that travel slowly and cause significant damage. Love waves are side-to-side surface waves, like a slithering snake. Rayleigh waves are rotational surface waves, somewhat like ripples from tossing a pebble into a pond.
Earthquakes are associated with many specific hazards, such as ground shaking, ground rupturing, subsidence (sinking), uplift (rising), tsunamis, landslides, fires, and liquefaction.
Some famous major earthquakes in history include: Shensi, China in 1556; Lisbon, Portugal in 1755; New Madrid, Missouri in 1811-1812; San Francisco, California in 1906; Anchorage, Alaska in 1964; and Loma Prieta, California in 1989.