Monday morning’s magnitude 4.7 earthquake in Riverside County was followed by more than 100 small aftershocks that radiated northeast, indicating that the quake occurred on a secondary fault of the San Jacinto fault. Follow this link to learn about the Anza quake.
The largest aftershock, a 3.2 quake, struck less than a minute after the first quake. The second, a 2.8 magnitude quake, occurred at 11:25 a.m. Another 2.8 quake occurred at 12:50 p.m. The vast majority of the aftershocks were largely imperceptible, with magnitudes smaller than 2.5. Valleys and other low elevation areas feel the effects most strongly. – LA Now
