Mammoth Lakes, in California’s Central Valley, is home to the Mammoth Mountain Ski Area, as well as thousands of people who had no idea that they were living above an active volcano. On December 8, 2017, 3 earthquakes – M3.7, M3.8 and M3.5 – struck about 20 miles southeast of Mammoth Lakes, California near the Nevada border. The two last quakes hit within 30 minutes and were preceded by the 3.7-magnitude quake earlier Friday in the same location in a cluster of faults between Bishop and Mammoth Lakes.
Mammoth Lakes is nestled within the Long Valley Caldera, grenaded into the Earth when the volcano blew up several thousand years ago. People figured that the steam vents, hot springs, mineral deposits and tectonic shifts were all just part of living in California, much in the same way that drowning is just part of living at the bottom of the ocean.