Los Angeles, CA -
The earthquake swarm that began on Sunday in Brawley, CA producing hundreds of quakes continues into Wednesday prompting an emergency declaration by city officials.
Some of the quakes have registered as high as 5.5 on the Richter scale and damage in Brawley and the surrounding area is still being tallied, but report show there to be widespread minor damage.
So far, more then 400 quakes registering at least 1.0 have been recorded since the swarm began later Saturday evening. The rate at which these earthquakes are happening is slowing down according to local officials and the USGS.
Seismologist say that unlike the San Andreas fault line that lies north of the Salton Sea where two tectonic plate, the North American plate and the Pacific plate are sliding past each other, south of the Salton Sea, the two plates are pulling away from each other in what is called the “Brawley Seismic Zone” according to Elizabeth Cochran of the USGS.
The last major swarm was in 2005, Cochran said, when the largest magnitude was a 5.1, but did not produce near as many quakes as this one. The largest swarm before last weekend's occurred in 1981, when the biggest quake topped out at 5.8, again not as many quakes occurred compared to this one.
New fears and questions have been raised as to whether this could be the prelude to "the big one" that has long been forecasted for Southern California. Cochran said this swarn does not change the risk and timeline that the big one could strike the area, but that residents should have emergency plans to be prudent.
State officials have been spending billions retro-fitting hundreds of bridges across California for new stronger earthquake protections over the last several years, including the high profile Oakland Bay Bridge that connects Oakland and San Francisco.