Yes, we have earthquakes, but not many big ones recently.
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Driving past Crowley Lake, one sees the Long Valley caldera, the blast crater from an eruption about 600,000 years ago, which lifted over 250,000 cubic kilometers of solid material into the atmosphere. By comparison, Mt. St. Helens produced a mere 250.
A somewhat different set of values is found in:
https://pubs.usgs.gov/dds/dds-81/Intro/GeologicMaps/GeologicHistory.html"Long Valley Caldera
The Glass Mountain eruptions, which were fed by a large, chemically evolving magma chamber in the shallow crust, culminated in the cataclysmic eruption of 600 cubic kilometers of high-silica rhyolite 760,000 years ago."
A more detailed description of the events is given in:
http://www.sciencedirect.com/science/article/pii/S0377027304001635 "Shortly before the 760-ka caldera-forming eruption, the mantle-driven focus of crustal melting shifted ∼20 km westward, abandoning its long-stable position under Glass Mountain and energizing instead the central Long Valley system that released 600 km3 of compositionally zoned rhyolitic Bishop Tuff (760 ka), followed by ∼100 km3 of crystal-poor Early Rhyolite (760–650 ka) on the resurgent dome and later by three separate 5-unit clusters of varied Moat Rhyolites of small volume (527–101 ka). "
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Several years ago we had a series of 6.nn quakes centered near Mammoth Lakes, CA.
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Does "several years ago" refer to the 1980 magnitude 6 quakes? Time flies when we're having fun!
Dale B. Dalrymple
