The Geologic Oddity in Washington; The World's Longest Andesite Lava Flow

Lava flows generally do not travel very far from a volcano. On rare occasions, a basaltic lava flow like those seen in Hawaii might stretch for 10 or 15 miles from an erupting vent. However, these vast distances are typically not obtained by more silica rich lava flows which have a viscosity similar to Molasses. Yet, in the recent geologic history of Washington State, two lava flows from the Goat Rocks wilderness area broke this rule. One of these lava flows was 46 miles or 74 kilometers long, representing the world's longest viscous lava flow. What I am referring to are the Tieton Andesite Flows.

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Graphics of eruption dates are courtesy of the Global Volcanism Program, Smithsonian Institute. https://volcano.si.edu/

Google Earth imagery used in this video: ©Google

Photo Credit: Coombs, M. L., Alaska Volcano Observatory / U.S. Geological Survey, https://avo.alaska.edu/images/image.p...

0:00 Laki Fissure Eruption
0:37 Speed of a Lava Flow
1:14 Tieton Andesite Flows
1:50 Goat Rocks Geology
2:56 1st Andesite Flow
4:01 2nd Andesite Flow

Citations:
https://wa100.dnr.wa.gov/south-cascad...
https://gsa.confex.com/gsa/2016AM/web...
https://www.geology.cwu.edu/discovery...
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