#okmok

USA, Alaska, Tulik, Mount Okmok - webcam

Eroded ash at Okmok caldera. This shield volcano in the Aleutian Island arc last erupted in 2008. Since then the tephra (volcanic ash) has eroded in a fractal shape, similar to one we published a couple of weeks back from the Mexican desert (see  http://tinyurl.com/krwztrf). When water erodes ash, it often forms rivers of dense mud laden water that can sweep everything before their path called lahars (covered at http://tinyurl.com/l2lpqgp). The volcano is a composite structure, made of lava and ash deposits and truncated by two overlapping calderas where the mountain has collapsed over an emptied lava chamber. The smoker is capable of major action, with VEI 6 explosive eruptions 8,300 and 2,400 years ago. The 2008 burp sent an ash plume 15km high into the skies, and deposited tonnes of ash over the island , which formed lahars that ran all the way to the coast. Loz Image credit: AVO/ADGGS http://www.volcanodiscovery.com/alaska/okmok.html http://www.avo.alaska.edu/volcanoes/volcinfo.php?volcname=Okmok http://voices.yahoo.com/okmok-caldera-volcano-unleashes-explosive-eruption-1670749.html

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Okmok Caldera, AK