A 4.7-magnitude earthquake shook southern California this morning, the latest in a series of small quakes to hit the area. This weekend a series of lower-intensity quakes hit perilously close to the San Andreas fault, making seismologists nervous about the "Big One"—a quake that would devastate LA. So far no injuries have been reported.
Today's quake was centered three miles south of Bombay Beach, 90 miles from San Diego. It's unclear whether it was on the San Andreas fault, or a smaller one. Today's quake also produced two aftershocks, measuring 3.0 and 2.7. Starting on Saturday, 42 quakes hit the Salton Sea area, with the highest having a magnitude of 3.3. These series aren't especially unusual; a similar swarm of tremors occurred in 2001. But scientists call the incident "a flashing yellow light that tells you to be prepared."