Two Pairs of Earthquakes Rattle East Bay, Continues Quake Swarm

Update:

Consecutive 3.5-magnitude earthquakes near San Ramon shook large portions of the Bay Area this afternoon, according to U.S. Geological Survey data, continuing the East Bay’s torrent of temblors. USGS officials reported that the pair of earthquakes struck within seconds of each other at 4:21 p.m. along the Calaveras Fault, which intersects the Hayward Fault.

These were the two largest of 13 earthquakes above 2.5-magnitude that USGS officials have reported in San Ramon or nearby within the past week.

The USGS reports that four more quakes occurred Monday night, from imperceptible to jolts felt all the way to San Francisco. The smallest was 1.9 at 7:30 while the largest was 2.9 at 9:33. In fact, two quakes hit at 9:33--one was 2.9 followed roughly 50 seconds later by a 2.8 quake.

Counting earthquakes of lower magnitude, there were 201 small shakers in the past week as of 5:20 p.m. today.

Eleven of those earthquakes were registered by USGS’ system within the preceding hour. Besides the 3.5-magnitude duo, today’s second-largest temblor occurred at 4:02 p.m., when a 2.8-magnitude earthquake struck the area. That earthquake centered on the border of San Ramon and Danville, in the vicinity of the Crow Canyon Country Club at 711 Silver Lake Dr. It was the same location that a 3.4-magnitude earthquake struck at 6:10 a.m. Thursday, according to USGS data.

At the time, that was the largest temblor in the recent quake swarm. People as far away as Vallejo and Sunnyvale felt it, according to a USGS reporting system. Areas north of Vallejo and south of San Jose reported feeling the 3.5-magnitude shakers today, according to the USGS.

Police dispatchers from San Ramon and Danville said that they received no calls regarding injuries or structural damage.

Original story:

A 3.5-magnitude earthquake, now one of the largest earthquakes in a recent swarm of tiny temblors around the East Bay, was recorded this afternoon near San Ramon, according to the U.S. Geological Survey.

The quake was reportedly felt in Moraga, Dublin, Livermore, Union City, Oakland, Walnut Creek and Casto Valley.

About 20 minutes prior to the most recent quake, a 2.8-magnitude temblor hit along the Calaveras Fault at 4:02 p.m. A magnitude 3.1 earthquake struck near San Ramon Sunday afternoon. Sunday’s quake was reported around 3:30 p.m.

While not huge, the number of earthquakes hitting each day is rattling nerves.

Previous:

• East Bay Swarmed with Weekend Earthquakes

The earthquake is just one of many that have struck the area in roughly the last 10 days, according to USGS officials. The largest was a 3.4 preliminary magnitude quake centered near San Ramon struck Thursday at 6:10 a.m., USGS officials said.

October 17 marked the anniversary of the devastating Loma Prieta earthquake, which interrupted Game 3 of the “Bay Bridge” World Series in 1989.

Related:

• Recalling When Loma Prieta Interrupted the 1989 World Series ... and What Happened Next

Californians prepared for future earthquakes during the annual the Great California ShakeOut drill of 2015 last week.

On Aug. 24, 2014, a 6.1-magnitude earthquake in the North Bay killed one person, injured more than 200 others and caused millions of dollars in damage. A 4.0-magnitude quake that struck the Hayward fault in the East Bay in August rattled nerves, and elicited some unique responses that were captured on camera.

Additional quake coverage on Patch:

• Morning Earthquake Jolts East Bay
• WATCH: Local Weatherman Reacts To East Bay Earthquake While On Air
  
• Magnitude 4.0 Earthquake Strikes East Bay
• Rude Awakening! Watch These Two Cute Dogs React To East Bay Earthquake
• Are You Really Ready for the Next Big California Earthquake?
• NAPA QUAKE 2014: Click here for Patch’s Full Earthquake Coverage

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