Yes, The 5.5 Earthquake You Felt Was A Ridgecrest Aftershock
The earthquake that hit Southern California around 6:30 p.m. on Wednesday evening was basically an aftershock of last summer's Ridgecrest earthquakes, according to seismologist Dr. Lucy Jones.
The temblor was a magnitude 5.5 centered about 10 miles south of Searles Valley in the Mojave Desert. It originated at a depth of 6.9 kilometers.
"It is indeed an aftershock to the earthquake that occurred last July," Jones told KPCC's Nick Roman. "It's been 11 months since the main shock, and that is actually a pretty common pattern that we see. So when one earthquake happens, it makes other earthquakes more likely. And the bigger it is, the more earthquakes it triggers and the larger earthquakes it triggers. The number dies off with time, but the magnitude doesn't. The relative number of large to small stays the same."
Yes, an earthquake. A M5.5 at the very southern end of the 2019 Ridgecrest aftershock zone. This is a large late aftershock - do you remember that I said these are common?— Dr. Lucy Jones (@DrLucyJones) June 4, 2020
Jones also said 40,000 quakes have occured in the Ridgecrest area since last summer.
As she did when the first big Ridgecrest earthquake happened last year, Jones reminded everyone there's about a 5% chance a larger earthquake will follow.
That's what happened in the summer of 2019.
On July 4, 2019, a 6.4 magnitude earthquake hit the Ridgecrest area. A day later, a 7.1 magnitude earthquake hit the same area. The back-to-back earthquakes destroyed homes and sparked fires, causing $100 million of damage.
Residents of Ridgecrest and other towns in the Mojave Valley felt aftershocks, including a 4.9 earthquake on July 12, for weeks.
So far, there are no reports of serious damage in Ridgecrest, which is located in the northeast corner Kern County, approximately 150 miles from Los Angeles.
It appears that ShakeAlert issued a message about Wednesday night's earthquake, but it's unclear who received it. Anecdotally, most people in Los Angeles didn't seem to get the alert — but some did.
Currently under my table experiencing shaking. It worked! pic.twitter.com/et0OeCKULm— Julian Lozos (@seismogenic) June 4, 2020
Julian Lozos was in the San Fernando Valley when he got a warning on his phone. He told KPCC/LAist, "I was admittedly really excited to get the alert, because I haven't gotten one before. I downloaded the apps the day they were released, but hadn't seen them in action until today. It said San Bernardino County, so I knew I had some time. I got up and walked to my kitchen table and got under it, held on and waited. I'm a bad judge of time, but I'd say I felt shaking maybe 10 seconds later."
If shaking from an earthquake doesn't reach a certain threshold, which it may not have in much of Los Angeles county, ShakeAlert won't send a text alert to users.
GET READY FOR THE BIG ONE