GEOL 303 Lecture Notes - Lecture 14: Juan De Fuca Plate, 2010 Central Canada Earthquake, Lava Dome
Document Summary
Subduction fo the juan de fuca plate off the coast of norther california, oregon, and washington has produced. Cascade volcanoes have been active over the past 4000 years. St. helens erupted in a fashion that was not predicted. Rather than erupting through the summit crater, the initial blast was directed out of the northern flank of. North-flank bulge was the result of rising magma pushing out the north side of the volcano because its upward motion was blocked by a coherent lava dome from an older eruption. Earthquake triggers a giant landslide as bulge failed and slid downslope. Landslide resulted in a loss of confining pressure above the superheated groundwater system, producing a massive steam blast directed laterally to the north.
