That's what USGS was displaying on their map when I checked it
. The biggest was only 3.5, but 683 quakes are 80%
of the world's earthquakes in that 24-hour period.
L.A. Times story
: At 11,053 feet, Mammoth Mountain in California's Eastern Sierra is a lava dome complex on the southwest rim of Long Valley Caldera, although eruptions haven't occurred for some 57,000 years. The recent swarm of quakes in and around the mountain is being tied to recent "volcanic unrest" marked by gas emissions, tree die-offs and intrusions of upward-moving sheets of rock, according to ...