Nineteen earthquakes between magnitude M=1.0 and M=2.7 occurred in the Long Valley area since the last update on August 27, 2010. One, a M=1.9 earthquake at 10:53 PM on Aug. 27, was located within the caldera beneath the south moat 0.5 mile south of Whitmore Hot Springs. The others were located in the Sierra Nevada south of the caldera. The largest was a M=2.7 earthquake on Aug 30 at 12:38 AM located beneath the McGee Creek area 1 mile east of Mt. Baldwin. This was followed by six M>1 aftershocks and a number of smaller earthquakes over the next ten minutes. Four small (M<1) earthquakes occurred beneath Mammoth Mountain, two on Aug 29 and two on Sept. 2. Post-processing analysis has identified a M 2.3 long-period earthquake beneath the summit of Mammoth Mountain that occurred during the previous week (August 23 at 2:17 PM).
