UPDATE: Nearly 200 small earthquakes — including three of a magnitude greater than 4 — struck the Salton Sea area over the last day or so. According to the U.S. Geological Survey, the swarm of quakes started early Monday morning and continued into the evening. Quakes measuring 4.3 and 4.2 magnitude occurred Monday night. Nine of the quakes measure greater than 3.0. Many of the quakes were centered near Bombay Beach.

They were felt in a relatively small area around the Salton Sea, according to the USGS. Swarms of small to moderate earthquakes are fairly common in the area. In 2009, the Salton Sea saw a swarm of more than 200 small quakes. The sea sits atop a very thin crust that is being constantly stretched as the North American and Pacific plates grind against each other. The area is also veined by dozens of faults — most notably the San Andreeas — that run parallel to and crisscross one another. READ MORE