Large 7.1-Magnitude Earthquake Hits Southern California Tonight at 8:19pm

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Magnitude 7.1 earthquake in Ridgecrest, CA today. image: cbsnews

According the US Geological Survey (USGS), a large 7.1-magnitude earthquake struck Ridgecrest, California today at 8:19pm PT.

“A magnitude 7.1 earthquake has occurred tonight (July 5; 08:19pm PDT) in the Searles Valley. USGS websites are currently slow due to immense web viewing traffic.

The preliminary magnitude has been updated from M6.9 to M7.1.”

– USGS today at 9:20pm PT

This earthquake was the largest in this region of California in 20-years.

According to Wikipedia, this was the 12th largest earthquake in California in recorded history.

California’s governor is responding to the quake thus tonight: 

“In response to another large earthquake in Southern California tonight, I have activated the state operation center to its highest level. The state is coordinating mutual aid to local first responders.”

– California governor Gavin Newsom

Kern County fire officials and CNN are reporting multiple fires and injuries in the Ridgecrest area caused by the quake:

“Multiple fires and injuries have been reported in Ridgecrest — about 150 miles from Los Angeles — after Friday’s earthquake, Kern County spokeswoman Megan Person told CNN. An emergency operations center is being set up in Bakersfield, she said”

CNN, today

Image of earthquake damage from yesterday’s quake. image: USGS

This earthquake was felt in Los Angeles, Mammoth Lakes, and as far away as Sacramento, Las Vegas, and Mexico..

Some SnowBrains users are reporting having felt this quake in North Lake Tahoe – over 300-miles away from the epicenter.

There was also a 6.4-magnitude earthquake yesterday, July 4th, 2019 in Ridgecrest, CA.

That 6.4-magnitude earthquake caused minor damage and some injuries in around Ridgecrest.

This 7.1-magnitude quake was 5 times larger and released more than 11 times the amount of energy than the 6.4 one.

There have been over 1,400 aftershock earthquakes since yesterday’s earthquake, according to the USGS.

This 7.1-magnitude earthquake today was much larger than yesterday’s quake.

The NBA Summer League game between the New Orleans Pelicans and New York Knicks in Las Vegas, NV was delayed tonight due to the earthquake.

Image of earthquake damage from yesterday’s quake. image: USGS

Geologist warned that yesterday’s quake could lead to a larger quake and it appears they were right.

Dr. Michio Kaku said today before today’s quake that “We’re long overdue” for a very big earthquake.

Kaku goes on to state that “we are playing Russian roulette with Mother Nature.”

All the earthquakes over 2.5-magnitude in the past 24 hours in California. image: USGS

Today’s quake was larger than the famous 1994 Northridge quake which measured 6.6-magnitude, killed 57 people, and left 125,000 people homeless.

The Northridge earthquake hit a high population area while today’s earthquake hit a very low population area of the Mojave Desert.

No tsunami advisories have been issued at this time.

Earthquake shaking potential in California.


Tectonic Summary:

On July 5th, 2019, at 8:19pm PST a magnitude 7.1 earthquake occurred as the result of shallow strike slip faulting in the crust of the North America plate in eastern California, southwest of Searles Valley. Focal mechanism solutions for the earthquake indicate rupture occurred on a steeply dipping fault as the result of either right lateral slip on a plane striking NW-SE, or as left lateral slip on a plane striking SW-NE. At the location of this earthquake, the Pacific plate moves to the northwest with respect to the North America plate at a rate of approximately 2 inches/yr. The location of the earthquake falls within the Eastern California shear zone, a region of distributed faulting associated with motion across the Pacific/North America plate boundary, and an area of high seismic hazard. More detailed studies will be required to precisely identify the causative fault associated with this event, though seismic activity over the past 2 days has been occurring on two conjugate fault structures in the Airport Lake Fault Zone.

This earthquake occurred approximately 34 hours after and 6.8 miles northwest of a M6.4 event in the same region, on July 4th, 2019, at 10:33am PST. The July 4th event was preceded by a short series of small foreshocks (including a M4.0 earthquake 30 minutes prior), and was followed by a robust sequence of aftershocks, including almost 250 M2.5+ earthquakes (up until the M7.1 event). Those events aligned with both nodal planes (NE-SW and NW-SE) of the focal mechanism solution of the M6.4 event, which was very similar in faulting style to today’s M7.1 earthquake. The sequence includes two other M5+ earthquakes, one of which occurred 20 seconds before the M7.1 event. The M7.1 earthquake occurred at the NW extension of the prior sequence.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Strike-slip-faulting events of the size of the July 5, 2019, earthquake are typically about 45×10 miles (length x width).

This region of eastern California has hosted numerous moderate sized earthquakes. Over the past 40 years, prior to the July 4th event, 8 other M5+ earthquakes have occurred within 30 miles of the July 6th, 2019 earthquake. The largest of these was a M5.8 event on September 20, 1995, just 1.8 miles to the west of today’s event, which was felt strongly in the China Lake-Ridgecrest area, and more broadly from Los Angeles to Las Vegas.

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