5.0 Earthquake Jolts Bay Area; No Injuries Reported

A magnitude 5.0 earthquake that struck on the San Andreas fault northwest of San Francisco on Tuesday evening was felt throughout the Bay Area, but police had no reports of damage or injuries.

Street lights swung in San Francisco and some items dropped from shelves in the 6:06 p.m. quake.

Scientists with the U.S. Geological Survey said the quake occurred at a depth of 4.3 miles. Their maps showed it was under the town of Bolinas, 17 miles from San Francisco and the site of some of the heaviest shaking in the devastating San Francisco earthquake of April 18, 1906.

Four light aftershocks of 2.1, 1.7, 2.0 and 2.2 were reported at 6:41, 7:11, 7:29 and 8:32 p.m.

The Geological Survey said “the probability of a strong and possibly damaging aftershock in the next seven days is less than 10%.”

It said there was a 5% to 10% chance of a quake larger than Tuesday’s night’s in the same period.

Bolinas marks the spot where the San Andreas fault enters the sea off San Francisco. As it proceeds south, it comes ashore again on the San Francisco Peninsula just south of the metropolis.

There have been a few quakes in the magnitude 3 range in the vicinity in recent years, but nothing stronger. The damaging magnitude 6.9 Loma Prieta quake of Oct. 17, 1989, was located near the San Andreas fault but about 70 miles south of San Francisco.

The San Andreas fault zone is comparatively wide as it enters Bolinas Lagoon, and tears in the earth caused by the 1906 rupture were evident only for a few months on the sand spit at the mouth of the lagoon.

Tuesday evening’s quake was described by those who felt it as fairly sharp and severe, but it was felt for only about five or six seconds in San Francisco and 10 to 15 seconds near the epicenter.

A 5.0 quake could be expected to cause light damage in an urban area, but the Bolinas area is not heavily populated.

Toby Bisson, a utility operator with the Stinson Beach Water District just south of Bolinas, told the Associated Press that the quake started with what seemed to be several explosions that frightened his 5-year-old daughter.

“She freaked out,” he said. “She started crying. She said, ‘I don’t like earthquakes’ and started running in the house. It took a while for her to come down. It was just loud and scary.”