5.3 Temblor Jolts Eastern Sierra, White Mountains

Earthquake activity persisted in the Eastern Sierra and the White Mountains on Saturday after a 5.3 quake late Friday night--the second of an identical magnitude within two weeks along the California-Nevada border.

Meanwhile, 80 more temblors were reported in the Mammoth Lakes area, including one registering 3.3 centered a mile southwest of the town.

Neither damage nor injuries have been reported in any of the quakes, but they have excited interest among scientists who have been monitoring possible volcanic precursors in the Mammoth region since 1980.

On Friday, at a media briefing at USC, the scientist in charge of the Southern California Earthquake Center, UCLA professor David Jackson, said he agrees with scientists who say the quakes along the California-Nevada border are connected with the quakes near Mammoth Lakes.

Jackson said it remains undetermined exactly how they may be connected. But scientists have become more aware that there are long-distance relationships between faults, and quakes in one fault system can trigger quakes in others.

The 5.3 jolt that occurred Friday at 10 p.m. was centered 32 miles southeast of Bishop, in the same area as a 4.5 temblor Nov. 5. At a depth of three miles, it was considered quite shallow, and could have caused damage in a more populated area.

Since Nov. 1, numerous quakes have taken place in an uneven triangle bounded by Mammoth at the western end in the Sierra range, western Nevada on the east, and Deep Springs, southeast of Bishop, at the southern end.

Both the 5.3 temblor Nov. 1 in western Nevada, and Friday night’s 5.3 quake near Deep Springs, were in the White Mountains.

The sides of the triangle are about 35 miles by 40 miles by 50 miles, but the entire region has a history of volcanic activity extending back hundreds of thousands of years.

A slim possibility, according to Lucy Jones of the U.S. Geological Survey, is that so many moderate earthquakes, in the 4 and 5 magnitude range, could presage a larger quake somewhere in the vicinity soon.

Ross Stein, another U.S. Geological Survey scientist, said earlier this month that the continuing swarms of quakes near Mammoth Lakes are exerting a seismic strain on the entire region, and that the many, fairly strong temblors of the last 15 to 20 years near Bishop and beyond are evidence of it.

The latest 5.3 quake was followed by a 3.8 aftershock in the same vicinity 42 minutes later, then, nearly five hours after that, by a 3.0. The location of Saturday’s 3.3 west of Mammoth Lakes was about five miles west of most of the quake swarm that reached a peak Thursday with a total of 549 separate quakes that day.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Mountain Quakes

There have been numerous earthquakes over the last two weeks in the Eastern Sierra near Mammoth Lakes and in the White Mountains both northeast and southeast of Bishop, Scientists say volcanic processes are at work in the area and all the quakes may be connected.