Nearly 200 Earthquakes Have Hit The Salton Sea In A Two-Day Span
Almost 200 earthquakes have struck the Salton Sea area since early Monday, reports the L.A. Times.
Most of the earthquakes were small, measuring under a magnitude of 3.0. The strongest ones reported so far both had a magnitude of 4.3. According to the Southern California Seismic Network, the swarm of earthquakes (mostly centered around Bombay Beach) began at 4:03 a.m. on Monday.
Jennifer Andrews of the Caltech Seismological Laboratory told CBS2 that the earthquakes had spawned 67 aftershocks on Monday, and that more aftershocks should be expected. She adds that there's a very low chance (about 5 %) that an aftershock larger than magnitude 3.2 will occur. As the trusty Dr. Michio Kaku explained on MSNBC, earthquakes and aftershocks are different phenemona. An earthquake happens when plates underground grind against each other and release energy. An aftershock, however, happens when those newly-shifted plates settle into their new arrangement.
The cluster of earthquakes is happening near the southern terminus of the San Andreas Fault, notes the SCSN. This isn't as scary as it sounds, because the earthquakes aren't actually happening on the San Andreas Fault. Rather, they're happening on an extensional fault that runs underneath the Salton Sea. As noted by the Times, these earthquake swarms aren't uncommon for the area, as dozens of fault lines lie in the area. Seismologist Lucy Jones reiterated some of these facts on Twitter. She also says that the swarm is not indicative of The Big One:
Today's Salton EQs in the extensional zone south of San Andreas. Extensional faults more likely to produce swarms.— Dr. Lucy Jones (@DrLucyJones) September 27, 2016
Swarms similar to today's in 2001 & 2009. 2009 had two days of small EQs between 2 M4s— Dr. Lucy Jones (@DrLucyJones) September 27, 2016
M4s near San Andreas increase chance of big EQ by a little bit. But we have swarms without big EQ - most likely nothing more will happen— Dr. Lucy Jones (@DrLucyJones) September 27, 2016