Swarm of earthquakes detected eight miles from the San Andreas Fault raises risk of ‘big one’ hitting in the next week
- San Andreas Fault in California was hit by an earthquake swarm Monday
- The quakes began in the early hours with the largest a magnitude 4.6
- Experts have laid out three possible scenarios that could happen this week
- One being a magnitude 7 or higher could rock the San Andreas Fault
A swarm of earthquakes detected just eight miles from the southern end of the San Andreas Fault in California have raised alarm bells that a larger quake could be on its way.
The US Geological Survey (UGS) recorded a magnitude 4.6 earthquake at 5:56am ET Monday beneath the Salton Sea, which was the largest among the swarm to hit.
The collection of shakes began with a magnitude 3.2 at 3:33am, followed by magnitude 4 quakes at 6:03am and 9:29am.
This part of San Andreas is capable of producing the ‘big one’, a magnitude 7 and above, but the USGS said the last time an event of this size hit the area was over 300 years ago.
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A swarm of earthquakes were detected just eight miles from the southern end of the San Andreas Fault in California, raising alarm bells that a larger quake could be on its way. The collection of shakes began with a magnitude 3.2 at 3:33am, followed by magnitude 4 quakes at 6:03am and 9:29am
The San Andreas Fault is a piece of the Earth’s crust that stretches more than 800 miles from the Gulf of California through the western area of the state.
The region shifts, due to tectonic movement associate with the occasional large earthquakes, which is why experts are weary the ‘big one’ could be on the horizon.
The reason for the concern is Monday’s swarm is only the fourth to occur in the past 88 years.
‘The southernmost section of the San Andreas Fault is capable of rupturing in large magnitude earthquakes (magnitude 7+), but the last earthquake that strong was more than 300 years ago,’ USGS shared in a statement.
This part of San Andreas is capable of producing the ‘big one’, a magnitude 7 and above, but the USGS said the last time an event of this size hit the area was over 300 years ago
‘In a typical week, there is approximately a 1 in 10,000 chance of a magnitude 7+ earthquake on the southernmost San Andreas Fault.’
‘That probability is significantly elevated while swarm activity remains high.’
UGS has laid out three possible scenarios that could occur this week, as a result of the small swarm.
The first, which has about an 80 percent chance, suggests the earthquakes could continue, but they will not be larger than magnitude 5.4 over the next seven days.
A second options, with 19 percent chance, is a larger quake at magnitude 5.5 to 6.9 could happen and the last, but least likely, would be a magnitude 7 or higher – this scenario has just a one percent chance of happening.
Although UGS has a few options of what could happen over the next seven days, they are uncertain how long the activity from the swarm will last.
‘We include this uncertainty in swarm duration in our forecasts,’ the agency wrote in a statement.
‘The chance of large earthquakes will remain elevated as long as the swarm continues.
‘About half of the swarms in this area are over within a week. We will update our forecast as swarm activity increases or decreases, or if larger earthquakes occur.’
IS CALIFORNIA AT RISK OF A DEVASTATING MEGAQUAKE?
A recent report from the U.S. Geological Survey has warned the risk of ‘the big one’ hitting California has increased dramatically.
Researchers analysed the latest data from the state’s complex system of active geological faults, as well as new methods for translating these data into earthquake likelihoods.
The estimate for the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7% to about 7.0%, they say.
‘We are fortunate that seismic activity in California has been relatively low over the past century,’ said Tom Jordan, Director of the Southern California Earthquake Center and a co-author of the study.
Shown above is the chance of an earthquake across California over the next 30 years
‘But we know that tectonic forces are continually tightening the springs of the San Andreas fault system, making big quakes inevitable.’
Seismologist Lucy Jones from the US Geological Survey warned recently that people need to accept the fact catastrophe is imminent, and prepare themselves accordingly.
Dr Jones said our decision to not accept it will only mean more people suffer as scientists warn the ‘Big One’ is now overdue to hit California.
Dr Jones, who is from the US Geological Survey said there are three key reasons why the peril is so frightening – it cannot be seen, it is uncertain and it seems unknowable.
This means people bury their heads in the sand and pretend it won’t happen.
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