Emergency responders from California, Alaska, Arizona, Colorado, Nevada and Washington are participating in a disaster exercise this week to test their response in the event of a 6.8-magnitude earthquake in the Bay Area.
The exercise comes two days after two small earthquakes struck within minutes of each other in the East Bay near Mount Diablo Sunday afternoon, and a third occurred near The Geysers in Sonoma County.
As part of the drill, the earthquake will simulate the loss of and damage to major infrastructure resources. Major bridges, drinking water supplies, wastewater treatment facilities, and chemical and radiological facilities could potentially be impacted if such a quake were to rock the Bay Area.
The simulated earthquake along the Hayward Fault is a collaborative effort between the U.S. Environmental Protection Agency offices in Denver, Seattle and San Francisco, the U.S. Coast Guard and California's Department of Toxic Substances Control.
The exercise, called the Great State Shake, now under way, ends Thursday.
The first of Sunday's small earthquakes, according to the USGS, was a 3.2 magnitude earthquake that struck shortly before 3:55 p.m. in an area seven miles south-southwest of Brentwood and eight miles east-northeast of Blackhawk. About two minutes later, a 2.8 magnitude earthquake struck in the same location, according to the USGS.
The 3.2 magnitude earthquake had a depth of 7.2 miles, while the 2.8 magnitude had a depth of 6.6 miles, according to the USGS.
A 2.9 magnitude earthquake also struck in the North Bay Sunday. According to the USGS, that quake struck shortly after 3:30 p.m. and had a depth of 1.3 miles. It was centered five miles east-southeast of The Geysers and 16 miles east of Cloverdale, according to the USGS.