Tahoe region rattled by series of small quakes

MINDEN (AP) - A series of small earthquakes rattled northern Nevada and the Lake Tahoe area on Friday, startling some residents but causing no damage.

The first quake struck at 8:06 a.m. and registered 2.6 in magnitude, according to a U.S. Geological Survey Web site. It was centered nine miles south of Dayton.

It was followed three minutes later by a 4.2 jolt seven miles east of Johnson Lane in Douglas County. The magnitude was revised upward after an initial estimate of 3.8.

That temblor was felt by many residents in the Carson City and Douglas County areas.

A dispatcher with the Douglas County sheriff's office in Minden said a few people called, but no damage was reported.

At least five aftershocks in the range of 1.4 to 1.7 were registered in the vicinity over the next few hours.

All the quakes were located in the Pine Nut Mountains, a 35-mile long range that stretches through portions of Lyon and Douglas counties and Carson City. The highest peak, at 9,451 feet, is Mt. Siegel.

Scientists at the University of Nevada, Reno, said dozens of small aftershocks were likely in the coming days, though most likely would not be felt.

The researchers were analyzing data to determine the kind of motion or slip mechanism associated with the quakes.

"There are so many faults in that area," said Tom Rennie, a seismic record technician at the UNR laboratory.

Earthquake magnitudes are calculated according to ground motion recorded on seismographs.

An increase in one full number - from 6.5 to 7.5, for example - means the quake's magnitude is 10 times as great.

Quakes less than a magnitude 3 often are unnoticed by people.

A quake with a magnitude of 6 can cause severe damage, while one with a magnitude of 7 can cause widespread, heavy damage.

The quake that struck Los Angeles in January 1994 caused an estimated $40 billion in damage and killed 72 people. It was a magnitude 6.7.