Experts monitoring small earthquakes on California’s San Andreas Fault

by Karen Faulkner, Worthy News Correspondent

(Worthy News) – Seismic experts are monitoring a swarm of small earthquakes that struck under the Salton Sea in California Monday, to assess the possibility of their becoming a large event on the San Andreas Fault, Yahoo News reports. There is a reported 20% possibility of a magnitude 7 or larger earthquake on the San Andreas Fault over the next 30 years.

According to the US Geological Survey, the largest in Monday’s swarm of small quakes was a magnitude 4.6 that took place at 8:56 a.m. under the southeastern section of the Salton Sea, Yahoo News said. This tremor was one of a series that started at 6:33 a.m. with a magnitude 3.2 quake. There were subsequent magnitude 4 tremors at 9:03 a.m. and at 12:29 p.m.

In 88 years, this is the fourth time such a swarm has been recorded in this area of California. The last time was in 2016, when two quakes at magnitude 4.3 and at magnitude 4.1 respectively “prompted a rare warning by the U.S. Geological Survey,” Yahoo News said. This warning caused San Bernardino to its close its City Hall for two days: the city hall building was about to vacated in any event because of concerns about its vulnerability to seismic activity. In the event, there was no larger quake.

USGS research geophysicist Morgan Page told Yahoo News that Monday’s swarm “does increase the chance of a big earthquake on the San Andreas somewhat. So it’s definitely something to watch.” Although, Page added: “It’s not necessarily doom and gloom, given that the last three similar swarms — in 2001, 2009 and 2016 — did not result in larger, catastrophic quakes.”

In any event, Page said: “Every time it happens, we do worry that this could be the time that it triggers something.”

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