Caltech-USGS: Glen Avon Swarm Won’t Trigger `The Big One’

Caltech-USGS: Glen Avon Swarm Won’t Trigger `The Big One’

News Staff

The big one will not be triggered by an earthquake swarm that struck in Riverside and San Bernardino counties over the past eight days, scientists at Caltech and the U.S. Geological Survey said Monday.

The so-called Glen Avon Earthquake Swarm occurred began on May 25 and continued through Monday, the largest a magnitude-3.2 on Sunday about 3 miles north-northwest of Glen Avon. There were a total of 430 quakes as of this morning, 23 of them between magnitude-2 and magnitude-3, according to the USGS.

In addition to the one Sunday morning, one other quake topped magnitude-3, a magnitude-3.1 that struck on May 25, according to Caltech and the USGS.

Despite their small magnitude, some of the quakes were felt because of their relatively shallow depth of about 1.6 miles.

“Based on past historic recordings, this swarm is only expected to generate events of magnitude less than 4.0,” according to a Caltech-USGS statement.

Quakes in the area between Chino and Riverside are common, according to Caltech and the USGS.

“Earthquake swarms are characterized as clusters of events in space and time that have no obvious mainshock,” according to the Caltech-USGS statement.