Two Types of Lava
Pāhoehoe (on the left) is basaltic lava that has a smooth, billowy, undulating, or ropy surface. These surface features are due to the movement of very fluid lava under a congealing surface crust.
ʻAʻā (on the right) is basaltic lava characterized by a rough or rubbly surface composed of broken lava blocks called clinker. The clinkery surface actually covers a massive dense core, which is the most active part of the flow. As pasty lava in the core travels downslope, the clinkers are carried along at the surface.
The Hawaiian words were introduced as technical terms in geology by Clarence Dutton, who was head of the division of volcanic geology at the United States Geological Survey in the 1880's.
I can confirm from personal experience that it is quite easy to walk on pāhoehoe, but the loose, broken, and sharp, spiny surface of an ʻaʻā flow makes hiking difficult, slow and very hard on both feet and shoes.
I hope your week ahead has more pāhoehoe than ʻaʻā. Thanks, as always, for stopping by and for all of your kind comments -- I appreciate them all.
© Melissa Post 2015
All rights reserved. Please respect my copyright and do not copy, modify or download this image to blogs or other websites without obtaining my explicit written permission.
Two Types of Lava
Pāhoehoe (on the left) is basaltic lava that has a smooth, billowy, undulating, or ropy surface. These surface features are due to the movement of very fluid lava under a congealing surface crust.
ʻAʻā (on the right) is basaltic lava characterized by a rough or rubbly surface composed of broken lava blocks called clinker. The clinkery surface actually covers a massive dense core, which is the most active part of the flow. As pasty lava in the core travels downslope, the clinkers are carried along at the surface.
The Hawaiian words were introduced as technical terms in geology by Clarence Dutton, who was head of the division of volcanic geology at the United States Geological Survey in the 1880's.
I can confirm from personal experience that it is quite easy to walk on pāhoehoe, but the loose, broken, and sharp, spiny surface of an ʻaʻā flow makes hiking difficult, slow and very hard on both feet and shoes.
I hope your week ahead has more pāhoehoe than ʻaʻā. Thanks, as always, for stopping by and for all of your kind comments -- I appreciate them all.
© Melissa Post 2015
All rights reserved. Please respect my copyright and do not copy, modify or download this image to blogs or other websites without obtaining my explicit written permission.