A swarm of new earthquakes shakes a larger area 4.2

SAN RAMON — Just when it seemed like it was over, the ground started shaking again: A series of more than 50 small earthquakes Monday ended what had been a recent break from weeks of tremors in the East Bay.

While most of the Bay Area may not have felt it, there was a significant amount of seismicity in San Ramon, where a swarm of earthquakes — or perhaps more than one earthquake — gave scientists and residents a series of small tremors.

As of 2:06 p.m. Monday, the USGS had measured 52 earthquakes — 38 of them with a magnitude of at least 2.0 — in the San Ramon area. Among them, 21 shook with magnitude 2.5 or more.

The first earthquake struck at 6:27 a.m. Monday. It was a 3.8, followed 34 minutes later by the largest tremor of the series — a 4.2 tremor that could be felt as far away as Concord and on the Peninsula. Other earthquakes of magnitude 3.8, 3.3, 3.1 and 3.0 also occurred in the swarm. The rest measured below 3.0 degrees, a level at which most people don’t feel vibration.

All of the tremors came after a 3.1-magnitude tremor Friday morning was centered about 3 miles southeast of San Ramon.

Although earthquakes are small in size, they are not without any impact. Monday morning’s earthquakes delayed BART’s flight. The trains ran at reduced speeds while the company completed track safety inspections. The delay was expected to be at least 20 minutes system-wide. BART said its routes were fine, and those delays diminished as the day progressed.

A BART train stops on the tracks at Walnut Creek Station due to an earthquake in San Ramon on Monday, February 2, 2026. BART is running the trains at a reduced speed while conducting a system-wide safety inspection. (Jose Carlos Fajardo/Bay Area News Group)

Monday’s seismic tremor was among the busiest to begin in nearly 3 months. As of Friday’s quake, the earthquake swarm that began Nov. 9 around San Ramon had triggered 91 earthquakes of magnitude 2.0 and above. But the swarm slowed down. There have been no earthquakes of magnitude greater than 2.0 in the region since January 10.

“We had a little lull, and then it picked up again,” Sarah Minson, a research geophysicist at the USGS Earthquake Science Center at Moffett Field, said Monday morning.

Earthquake swarms are groups of dozens or even hundreds of small, usually harmless earthquakes. Scientists are still learning about them, and they said there are no strict standards for when swarms begin or end.

Many of the earthquakes that have struck San Ramon in recent months were so small that people living on the outskirts of Contra Costa County, population 85,000, did not feel them. Since the swarm began in November, the numerous small earthquakes have not caused any damage or casualties, local authorities say, except for the occasional train slowdown. Authorities in San Ramon did not report any major damage or injuries from Monday’s wave.

Typically, earthquake swarms occur near volcanoes or geothermal fields.

But the geology beneath the San Ramon Valley, which runs roughly from Walnut Creek to Dublin along Interstate 680, is a complex mix of small faults, many without names, between the Calaveras Fault and Mount Diablo, which come together to sometimes cause bouts of small earthquakes, scientists say.

There have been five other large earthquake swarms in the San Ramon Valley since 1970. They occurred in 1970, 1976, 2002, 2003, and 2015, generating hundreds of earthquakes each time, almost all of them below magnitude 4.0. None of them caused serious damage or injuries.

“This is a unique area,” Minson said. “This process has been going on for a long time and will likely continue for millions of years.”

Although earthquake swarms can increase the chance of a larger quake, it is only by a very small amount, the scientists said. Importantly, none of the previous San Ramon swarms caused a major earthquake on the Calaveras Fault or other nearby faults.

“These are probably harmless,” Roland Borgmann, a professor of Earth and planetary sciences at UC Berkeley and the UC Berkeley Seismology Laboratory, said in an interview last week during the lull. “But it’s a good reminder that we have to be prepared for earthquakes.”

In light of the recent spike in small earthquakes in San Ramon, seismic researchers are reviewing the historical record to see if they can discern other patterns or ideas, Minson said.

Scientific understanding of earthquake swarms around the world is still evolving, she said, and much is not yet known — including whether Monday’s activity should be called the start of a new swarm or a continuation of the swarm that began in November.

“It’s a matter of semantics,” she said. “You can say it’s the same squadron or a new squadron. They have this problem with TV shows. Do you call it a reboot or a sequel?”

She noted that Monday’s activity is a reminder of three things: First, science is an ongoing process. Secondly, the country of the Gulf region earthquake. Finally, it is important to know how to respond to earthquakes.

“If you feel shaky at any time, you should get down and hold on to protect yourself,” she said. “When you’re hosting your own Super Bowl party, feel free to let people know. And it’s okay to take your snacks with you under the table.”

What Are The Main Benefits Of Comparing Car Insurance Quotes Online

LOS ANGELES, CA / ACCESSWIRE / June 24, 2020, / Compare-autoinsurance.Org has launched a new blog post that presents the main benefits of comparing multiple car insurance quotes. For more info and free online quotes, please visit https://compare-autoinsurance.Org/the-advantages-of-comparing-prices-with-car-insurance-quotes-online/ The modern society has numerous technological advantages. One important advantage is the speed at which information is sent and received. With the help of the internet, the shopping habits of many persons have drastically changed. The car insurance industry hasn't remained untouched by these changes. On the internet, drivers can compare insurance prices and find out which sellers have the best offers. View photos The advantages of comparing online car insurance quotes are the following: Online quotes can be obtained from anywhere and at any time. Unlike physical insurance agencies, websites don't have a specific schedule and they are available at any time. Drivers that have busy working schedules, can compare quotes from anywhere and at any time, even at midnight. Multiple choices. Almost all insurance providers, no matter if they are well-known brands or just local insurers, have an online presence. Online quotes will allow policyholders the chance to discover multiple insurance companies and check their prices. Drivers are no longer required to get quotes from just a few known insurance companies. Also, local and regional insurers can provide lower insurance rates for the same services. Accurate insurance estimates. Online quotes can only be accurate if the customers provide accurate and real info about their car models and driving history. Lying about past driving incidents can make the price estimates to be lower, but when dealing with an insurance company lying to them is useless. Usually, insurance companies will do research about a potential customer before granting him coverage. Online quotes can be sorted easily. Although drivers are recommended to not choose a policy just based on its price, drivers can easily sort quotes by insurance price. Using brokerage websites will allow drivers to get quotes from multiple insurers, thus making the comparison faster and easier. For additional info, money-saving tips, and free car insurance quotes, visit https://compare-autoinsurance.Org/ Compare-autoinsurance.Org is an online provider of life, home, health, and auto insurance quotes. This website is unique because it does not simply stick to one kind of insurance provider, but brings the clients the best deals from many different online insurance carriers. In this way, clients have access to offers from multiple carriers all in one place: this website. On this site, customers have access to quotes for insurance plans from various agencies, such as local or nationwide agencies, brand names insurance companies, etc. "Online quotes can easily help drivers obtain better car insurance deals. All they have to do is to complete an online form with accurate and real info, then compare prices", said Russell Rabichev, Marketing Director of Internet Marketing Company. CONTACT: Company Name: Internet Marketing CompanyPerson for contact Name: Gurgu CPhone Number: (818) 359-3898Email: [email protected]: https://compare-autoinsurance.Org/ SOURCE: Compare-autoinsurance.Org View source version on accesswire.Com:https://www.Accesswire.Com/595055/What-Are-The-Main-Benefits-Of-Comparing-Car-Insurance-Quotes-Online View photos