Originally Posted by Chief Engineer
pahoehoe or aa-aa?
* * *
(also spelled aa
, pronounced [ˈʔɑʔɑː]
in Hawaiian English
, from Hawaiian
meaning "stony with rough lava", but also to "burn" or "blaze") is one of three basic types of flow lava. ʻ
ā is basaltic
lava characterized by a rough or rubbly surface composed of broken lava blocks called clinker
(also spelled pahoehoe
, pronounced /pəˌhoʊeˈhoʊe/
, Hawaiian English
, from Hawaiian, meaning "smooth, unbroken lava") 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."
The third type of lava is:
is the rock type typically formed when lava emerges from an underwater volcanic vent
or a lava flow enters the ocean. However, pillow lava can also form when lava is erupted beneath thick glacial ice. The viscous lava gains a solid crust on contact with the water, and this crust cracks and oozes additional large blobs or "pillows" as more lava emerges from the advancing flow. Since the majority of Earth
's surface is covered by water, also most volcanoes are situated near or under it, pillow lava is very common."
For a more detailed explanation of the three types of lava, go to:
Lava - Wikipedia, the free encyclopedia