The USGS says the first quake, a magnitude 3.2, was centered east of Highway 242 in Concord and struck at about 7:01 a.m. PDT Wednesday. The second and largest, a 3.6-magnitude, struck at 7:32 a.m. It was later downgraded to a 3.5. The third, a 2.6-magnitude, hit shortly after at 7:35 a.m.
Over 100 people, mostly in Pleasant Hill, reported feeling the earthquakes, according to USGS' online "Did You Feel It" survey.
People chimed in over Twitter after some light shaking.
And then ANOTHER one. That's enough, #Concord fault. Really. #earthquake https://t.co/0Z44t7H0XO
โ Daniel M. Jimenez (@DMJreports) May 6, 2015
3.6 #earthquake #concord in pleasant hill this morning. Definitely felt...
โ Jason Dupree (@JasonDupree1) May 6, 2015
This is becoming scary, it kept shaking!! #earthquake #Concord https://t.co/qX1tRiPqsd
โ Abdullah (@AbdoAlnamlah) May 6, 2015
There have been no reports of injury or damage.
Aftershocks continue to rattle the East Bay after a 3.6-magnitude earthquake struck the same area on Sunday afternoon.
The U.S. Geological Survey says an earthquake with a preliminary magnitude of 4.0 hit at 2:13 p.m. Sunday. That quake was later downgraded to a 3.6 by the USGS. It was centered a mile south of Concord, along the Concord fault.
Following the 3.6 quake, at least eight aftershocks were reported as of Wednesday.
1.8 โ 05/05 05:51 a.m.
2.8 โ 05/04 6:52 p.m.
1.6 โ 05/04 1:52 a.m.
1.5 โ 05/03 9:30 p.m.
2.3 โ 05/03 6:54 p.m.
1.6 โ 05/03 3:56 p.m.
2.1 โ 05/03 3:28 p.m.
3.0 โ 5/03 3:14 p.m.
Scientists says the Concord fault, which runs through Concord to Suisun Bay, has the potential to do major damage in the East Bay.
The Hayward and San Andreas faults steal most of the spotlight, but the Concord fault stretching from the Mount Diablo foothills to the Carquinez Strait could cause major damage due to its location.
"If we saw a 6.0 on Concord, we could see far more damage than we did in Napa," USGS Seismologist Dr. David Schwartz told KCBS news following Sunday's quake.
Even if the Concord Fault only produced a 5.0 quake, it could cause significant damage to refineries in the area.
There was a damaging 5.4-magnitude quake in 1955 that killed one person and caused property damage estimated at $1 million.
The USGS estimates there's a 3 to 4 percent probability of a magnitude-6.7 or higher earthquake striking on the Concord of lower Green Valley Fault in the next 30 years compared with 6.4 percent for the San Andreas and 14.3 percent for the Hayward Fault.
A series of smaller quakes shook the area in the moments before and after the larger one.
Strong earthquakes with an epicenter off the coast can trigger tsunamis, depending on the size and type of the fault movement. The Pacific Tsunami Warning Center tracks earthquake data for the West Coast.
I'm not so sure about the "Big One" as the grand finale for Governor Brown's California.
I can, however, visualize an event taking place whereby California falls into the Sea, as Edgar Cayce put it.
Imagine the Plates backing off, releasing the lifting force underneath.
Then, imagine the spongy ground beneath the surface because of excessive ground water pumping.
Add massive fracturing from the Miracle of Fracking.
The final round of quakes break it all loose, and down it goes.
My model may be wrong, or off a bit, but it is now easy for me to visualize the Sacramento Valley plunging down 50 feet (or more) and a Tidal Wave coming in and finishing the job.
Whalla! California falls into the Sea, a la Cayce.