:quality(85)/cloudfront-us-east-1.images.arcpublishing.com/infobae/Z46NE7TFQBD27LWRBRMW327WKY.JPG "The Los Angeles earthquake affected a fault system that could pose a major threat: this is known")
(KeynoteUSA)
The 4.4 magnitude earthquake that struck the Los Angeles area this week occurred in the area of a fault system that could pose an even greater threat to parts of the city than the famous Los Angeles fault. Saint Andrew. Monday’s movement and the recent ones earthquakes Smaller earthquakes that occurred nearby have renewed attention to the fault Puente Hills and the dangers it could entail.
The fault of Puente Hills It is a wide underground fault that runs through the counties of Los Angeles and Orangeeven under the city center, and scientists warn that it could one day produce a massive 7.5-magnitude tremor, which could rupture an area from Saint Gabrieleast of Los Angelesuntil Hollywoodnearly 32 kilometres away. According to some models, such an earthquake could cause around 18,000 deaths.
“We have an incredibly dense concentration of vulnerable buildings right on top of the fault line. Puente Hillsand that is what makes it especially dangerous,” he explained. Lucy Jonesseismologist and research associate of Caltech.
In this area, concrete structures built in the 1950s and 1960s, common in Los Angeles’ commercial real estate sector, are a major concern; two-thirds of them still need to be retrofitted to make them safer against earthquakes.
“Concrete is heavy,” Jones explained. “When we’ve run these models, those are the buildings that are killing a lot of people.”
The earthquake of Whittier Narrows of 1987, which occurred east of downtown Los Angeles on a branch of Puente Hillswas 5.9 magnitude and caused eight deaths and $358 million in material damage, according to the Southern California Earthquake Center.
:quality(85)/cloudfront-us-east-1.images.arcpublishing.com/infobae/2NN7QWCIVJAHVOZBQC3RD7PMQA.png "The Los Angeles earthquake affected a fault system that could pose a major threat: this is known")
The San Andreas Fault could cause a 7.8 magnitude earthquake that would affect Baja California. (Infobae/Archive).
The fault of Puente Hills It lies underground, buried beneath layers of rock and sediment. It is part of a stacked and tilted fault system, and while scientists are not sure which one exactly moved during Monday’s quake, Puente Hills She is a good candidate, according to Michael Oskinprofessor of geology at the University of California at Davis.
Known as “blind” thrust faults because they cannot be seen on the surface, they are difficult to study and may remain unknown to scientists until an earthquake occurs.
A thrust fault is a type of fracture in which one block of rock slides up and over another at a shallow angle. According to Oskin, the 1994 Northridge earthquakeof magnitude 6.7, also occurred on a blind thrust fault and led to an investigation that has allowed scientists to better understand its overall arrangement in the basin. Los Angeles.
“Northridge highlighted how destructive they could be because it was so much bigger than Whittier Narrows,” he explained.
Oskin said it’s not unusual to have multiple earthquakes on these systems, as Los Angeles has seen this summer. “The important lesson is that it’s a reminder that these faults are active, and we need to be prepared,” he said.
The south of California It is riddled with active faults – including many blind thrust faults between Los Angeles and Saint Barbara– and a few hundred of them are capable of producing a damaging earthquake, Jones said.
Many of them form in an area known as the “Great Bend” of the San Andreas Fault, where the Pacific and North American plates collide rather than slide past each other, building the mountains that surround Los Angeles and breaking up the land underground.
According to Jones, although the failure of Puente Hills is more dangerous, that of Saint Andrew moves faster and breaks more frequently.
“Over the next few thousand years, the San Andreas fault will hurt us more than the Puente Hills fault, because the Puente Hills fault will move once and the San Andreas will move 20 times,” Jones said.
:quality(85)/cloudfront-us-east-1.images.arcpublishing.com/infobae/73HJWE4XFBHCJPQWYQFIZM5C3E.png "The Los Angeles earthquake affected a fault system that could pose a major threat: this is known")
The fault of Saint Andrew It is the main dividing plate between the Pacific and North American plates and is capable of producing the largest earthquakes because it tends to break at great distances. It is one of the largest faults in the world and extends from Salton Seain the desert of southern Californiato Cape Mendocino, on the northern coast of the state.
It had not broken in the southern Golden State since Fort Tejon earthquake of 1857a 7.9 magnitude earthquake that shook a sparsely populated region at the time, killed one person and caused severe damage to a military post in Fort Tejon.
An earthquake of similar magnitude today in the area of Saint Andrew would have significant repercussions throughout the Los Angeles region, especially in Inland Empirethe metropolitan area that includes Riverside and San BernardinoAccording to researchers, such an earthquake is expected to produce two minutes of strong shaking and 1,800 deaths.
Experts say a major destructive earthquake is coming to California, and it’s not a question of if, but when, but the next one won’t necessarily be in the California area. Saint Andrew.
Jones says the earthquakes in southern California The last 20 years have been unusually quiet, with only five or six earthquakes of magnitude 4 or higher recorded each year. The long-term average is about 10 or 12 per year. This year, however, there have already been 13 quakes of magnitude 4 or higher.
“We are really a seismic country and we have been carried away by a feeling of complacency because we have had a calm period. It is clear that this year we are not calm,” he concluded.
Keynote USA
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