USGS Volcano Hazards Program Volcano Update

The real-time computer system located three small earthquakes in the vicinity of Long Valley caldera since the last update at 8:01 AM (PST) on November 18. A M=0.4 earthquake at 8:50 AM on the 18th was located beneath the southwest flank of Mammoth Mountain (1 mile west of Mammoth Pass). Three earthquakes were located beneath the Sierra Nevada south of the caldera. The largest was a M=1.6 event at 10:05 AM on the 18th located 4 miles NW of Round Valley.