9 small earthquakes shake San Ramon, powerful quake strikes Japan

9 small earthquakes shake San Ramon, powerful quake strikes Japan

Nine small to moderate earthquakes struck San Ramon on Monday morning, the largest one clocking in with a magnitude of 3.6, according to the US Geological Survey.

SAN RAMON, Calif. - Nine small to moderate earthquakes struck San Ramon on Monday morning, the largest one clocking in with a magnitude of 3.6, according to the US Geological Survey.

The two most recent were a magnitude 2.9 at 1:50 p.m. and a magnitude 2.6 at 1:59 p.m.

The other temblors ranged from 2.5 to 3.0. 

Eight of Monday’s quakes were centered near San Ramon. Since Nov. 9, the USGS has recorded more than 80 earthquakes in the area, a pattern seismologists describe as not unusual along the Calaveras Fault.

Swarm of earthquakes rattle East Bay

The East Bay experienced a swarm of earthquakes on Monday, nine in San Ramon and one in Piedmont.

"A lot of these earthquakes have been fairly shallow, so people have felt them," said Robert de Groot, a USGS scientist. "None of these sequences, none of these swarms have led to larger earthquakes. There’s a very small percentage of these earthquakes leading to a larger one."

Still, the repeated shaking rattled some people at work.

"It was a very scary experience, because I’ve grown up in California, but I don’t think I’ve felt this many earthquakes all at once," said San Ramon resident Gabby Slivka.

Adding to the anxiety, a separate and unrelated 2.9-magnitude earthquake struck just before 3 p.m. in Piedmont.

"I didn’t know it was earthquakes, but It was so strong I thought there was a truck that hit the front of the house, or a tree fell over the house," said Rachel Qoro, who works in Piedmont. 

USGS officials emphasized that small earthquakes are a natural part of life in the Bay Area and urged residents to stay prepared. De Groot advised people to "drop, cover and hold on" during shaking and to keep emergency kits ready. The agency also recommends downloading the ShakeAlert app, which can provide several seconds of advance warning.

Meanwhile, roughly 5,000 miles away, a powerful 7. 6-magnitude earthquake struck off northern Japan on Monday, triggering a tsunami of up to 40 centimeters in coastal communities in the region, the Japanese Meteorological Agency said.

Japan earthquake

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In Japan, the agency said the magnitude quake struck just east of Aomori, the northernmost prefecture of Japan’s main Honshu island, and just south of Hokkaido island. It said a tsunami of 40 centimeters struck the Hokkaido prefecture town of Urakawa and the Aomori prefecture port of Mutsu Ogawara.

Several people were injured at a hotel in the Aomori town of Hachinohe, public broadcaster NHK reported.

Prime Minister Sanae Takaichi, in brief comment to reporters, said the government set up an emergency task force to urgently assess the extent of damage. "We are putting people’s lives first and doing everything we can," she said.

Nuclear power plants in the region were conducting safety checks, NHK reported.

The Associated Press contributed to this report.