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QUAKE SWARM, SOUTHERN CALIFORNIA, USA 1st Oct 2020

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#Satellite images show giant #crack caused by #earthquake in #MojaveDesert, #California, #USA

Before and after imagery of the epicentre of the recent Ridgecrest Earthquake. Pic: Planet Labs Inc

Before and after images show the epicentre of Friday’s quake. Pic: Planet Labs Inc

The impact of Southern California’s strongest earthquake in 20 years has been revealed after satellite images showed how a huge crack emerged in the Earth’s surface.

The US state was rocked by two powerful earthquakes of magnitudes 7.1 and 6.4 last week along with hundreds of aftershocks.

The stronger quake on Friday struck 11 miles from the city of Ridgecrest, with satellite images by Planet Labs Inc showing the large crack that was ripped open in the Mojave Desert.

Move the slider from left to right to see the difference in images of the epicentre before and after the quake.

The US Geological Survey has reportedly said the crack is not a new fault line and the recent quake activity is not related to the dangerous San Andreas fault.

Before last week, the last time an earthquake above a magnitude of 6 struck Southern California was in 1999 when a 7.1 magnitude event – dubbed the Hector Mine quake – was recorded.

Friday’s quake ruptured gas lines and sparked numerous fires in Ridgecrest, about 125 miles from Los Angeles.

RIDGECREST, CALIFORNIA - JULY 04: A local resident inspects a fissure in the earth after a 6.4 magnitude earthquake struck the area on July 4, 2019 near Ridgecrest, California. The earthquake was the largest to strike Southern California in 20 years with the epicenter located in a remote area of the Mojave Desert. The temblor was felt by residents across much of Southern California. (Photo by Mario Tama/Getty Images)
The 6.4 quake caused a fissure near Ridgecrest in the earth last Thursday

Offices in central LA were shaken for around 30 seconds by the tremors, and the quake was also felt in the Hollywood Hills, Las Vegas and parts of Mexico.

It came after Southern California was struck by a 6.4-magnitude quake on Thursday, which was followed by a strong 5.4-magnitude aftershock in the early hours of the next morning.

The force of the earthquake left a crack through this highway Pic: Karaleigh Roe
The force of the earthquake cracked a road Pic: Karaleigh Roe

There were minor injuries but no reports of anyone seriously hurt or killed.

Fears of a large quake had grown recently after 1,000 small tremors were reportedly recorded in Southern California over three weeks.

The “swarmageddon” produced earthquakes with an average magnitude of 3 last month, the LA Times reported.

Fissures that opened up under a highway during a powerful earthquake that struck Southern California are seen near the city of Ridgecrest, California, U.S., July 4, 2019. REUTERS/David McNew
There have no reports of any fatalities

California officials are spending more than $40m (£32m) on an earthquake early warning system that – in addition to alerting the public – could also be used to automatically halt trains and open fire station doors moments before a major tremor actually strikes.

Emergency management officials have said they intend to have the statewide warning system in place by mid-2021 to serve California’s roughly 40 million residents.

Courtesy of Sky News

https://tinyurl.com/y5zgpfvb

Oklahoma earthquake 5.8 was state’s largest on record

earthquake-record
The U.S. Geological Survey upgraded the magnitude of the earthquake that rattled Oklahoma on Saturday to 5.8, making it the strongest ever recorded in the state’s history.
 
The previous record for an earthquake in Oklahoma was the Nov. 6, 2011, quake that hit Prague, which was also updated Wednesday from a magnitude 5.6 to 5.7.
 
Questions surrounding the size of both earthquakes prompted the events’ re-analysis, Gavin Hayes, a USGS research geophysicist, said in a statement. The data indicates while the two quakes are extremely similar in size, the most recent event is slightly larger, he added.
 
Shaking from the Saturday quake, centered in rural Pawnee County, could be felt over a seven-state area.
 
Gov. Mary Fallin said Saturday that three homes in Pawnee County were damaged by the quake and that at least three buildings in the city of Pawnee sustained some level of damage. An inspection of state highway and turnpike bridges also turned up “very minor issues,” she said.
 
The magnitude revision is based on further in-depth analysis of seismic recordings, the USGS said. Changes in estimated quake magnitude are common in the days after the event as more data are analyzed in greater detail than possible in the first minutes after the earthquake, the agency added.
 
An increase in magnitude-3.0 or stronger earthquakes in Oklahoma has been linked to underground disposal of wastewater from oil and natural gas production.
Courtesy of usatoday.com