Moderate quake sends shockwaves across lake

INCLINE VILLAGE - No significant damage or injuries were reported from a magnitude 4.5 quake on Lake Tahoe's North Shore early Thursday morning, although it was felt as far away as Newcastle, Calif., 70 miles to the southwest.

"I live in Reno, and it woke me up," said Bruce Erickson. "It really jolted the house and jarred me awake. It cracked the house."

The event hit at 1:55 a.m., and was sited on the state line about 6 miles north of Kings Beach at a depth of 5 miles, according to the University of Nevada, Reno Seismological Lab. It was preceded by several smaller foreshocks, the largest registering 3 on the Richter Scale at 1:25 a.m.

Bill Lopez, who was working at the Cal-Neva at the time, said he felt the first as a quick jolt and then the second.

"It made stress fractures in the ceiling, and a couple of lights fell out," he said.

The seismic activity is probably part of a northeast-trending regional deformation that extends through the southern Truckee Meadows. The Tahoe Basin and the Reno-Carson City urban corridor in general is known to have a significant seismic hazard. More than 10 quakes of magnitude 6 or larger have occurred there within the last 150 years.

This activity includes several events in the Tahoe Basin of similar size to yesterday's main shock, including a 1998 magnitude-4.9 Incline Village quake. More recently, a series of smaller quakes struck the same general area last year and in 2001.

"I wasn't frightened," she said. "I lived south of San Francisco and lived through some lulus."

Ellie Lindberg also said she felt the second temblor but not the first.

"It woke me up out of a sound sleep; it was really a jolt," she said. She had vivid memories of the 1989 Loma Prieta earthquake.

Ken Smith, an assistant research professor at UNR's lab, said that while Thursday's main quake site is close to the 1998 location, the two have distinctly different rupture styles. The earlier quake slipped mostly horizontally along a northeast-southwest direction. In contrast, Thursday's slip appears to be mostly "normal" or downward along an inclined fault plane, according to early results from seismologists at the University of California, Berkeley.