More Quakes in Mammoth Lakes

A spasm of relatively shallow volcanic earthquakes, with magnitudes of 3.8, 3.6 and 3.4, over a nine-minute period, shook an area six miles southeast of Mammoth Lakes on Friday morning, the U.S. Geological Survey reported.

Altogether, there were about 30 quakes between 11 a.m. and noon, with the three strongest occurring between 11:24 and 11:33 a.m. No damage was reported in the jolts, near the Mammoth airport.

The seven quakes that occurred during the nine-minute period, including four weaker ones, were mostly located about three miles below the surface, scientists said. After 11:33 a.m., most of the quakes occurred at a lower depth, four to five miles under the surface.

In the seven-month swarm of thousands of quakes near Mammoth, there has been a recent movement of most temblors to the east, six miles from the town of Mammoth Lakes instead of two to three, and a trend toward shallower depths.

Scientists are interested, because this may indicate a movement of magma, or molten rock, toward the surface. The Mammoth area has had no volcanic eruption for about 250 years.