Earthquakes Rattle Mammoth Lakes

Large numbers of volcanic earthquakes continued Saturday in the Mammoth Lakes area, but the strongest was only a mild magnitude 3.2, and scientists said the trend for the time being was for less activity.

The U.S. Geological Survey said at 4 p.m. that there had been 221 quakes thus far for the day, most centered five to seven miles southeast of Mammoth Lakes, between the airport and the fish hatchery.

The number of quakes in the last week totaled slightly over 2,100. Scientists monitoring the activity believe that magma, or molten rock, four or five miles underground is exerting pressure that is causing the quakes and some uplift of terrain. The strongest quake in the six-month swarm was 4.9 on Nov. 30.