The Coachella Valley has experienced more than 20 earthquakes in recent days, causing concern among some residents.
The 4.9 magnitude earthquake reported about 12 miles north of Indio on the evening of Monday, January 20 was the first moderate earthquake to hit the region in some time, after all.
Following many smaller aftershocks, a larger earthquake of magnitude 4.3 woke many residents from their sleep at 12:30 a.m. on Wednesday, January 21.
Signs guide hikers in the right direction on the Indio Hills Badlands Hiking Trail in north Indio, March 6, 2020.
With Californians constantly worried about “The Big One” — the anticipated massive earthquake that, by some measures, is overdue for the country’s West Coast — it’s understandable that some would be a little more nervous.
However, experts say the latest moderate earthquakes in Indio are relatively normal for the region. All earthquakes that followed the initial wave followed the typical aftershock pattern.
“The sequence works as you would expect, a typical post-4.9 decay,” said Kate Scharer, a research geologist at the US Geological Survey. “If you have a 4.9, you might get about 10 third magnitudes in the next week.”
It is not unheard of for earthquakes to be retroactively referred to as “foreshocks” for the main event. In 1992, the magnitude 7.3 Landers earthquake was preceded by a magnitude 6.1 earthquake in Joshua Tree more than a month earlier.
However, statistically speaking, such an event is highly unlikely.
Each earthquake has a 5 percent chance of being followed by an earthquake of equal or greater magnitude within a week, according to the USGS. The magnitude 4.9 quake in Indio has a 1 percent chance of being followed by a magnitude 7 or greater, Scharer said.
“It’s what we expect from this region,” she added. “We should expect to have these earthquakes.”
Fault lines
The latest cluster of earthquakes occurred on a little-known fault below Berdoo Canyon, a road that runs through Joshua Tree National Park.
About eight miles from the San Andreas fault, the latest earthquakes may be far enough away not to interact with it, but it’s impossible to predict.
One of the reasons geologists are interested in the interaction between fault lines is that the San Andreas fault is overdue for a major earthquake. A significant rupture has not occurred along the San Andreas Fault for about 300 years.
That’s a little longer than average, but not unheard of, according to Scharer.
“It’s a very good reminder that one day there will be a big earthquake that will be very challenging for your community or city,” she said. “And so it’s a good reminder to stop and ask what do you need to do to be more earthquake prepared?”
What should I do during an earthquake?
In the event of an earthquake, experts urge people to “drop, cover and hold.” Especially to prevent them from being crushed by heavy objects.
Falling to the ground prevents falling. Covering the head and neck will protect sensitive parts of the body. Experts also recommend that people crawl under a table or desk if they are nearby.
Why do earthquakes happen?
The Earth has four layers: the inner core, the outer core, the mantle and the crust. The crust and top of the mantle form another area called the “lithosphere,” which acts like a skin surrounding the Earth’s surface, USA TODAY reported.
The lithosphere, however, is not of one piece and exists as a puzzle or a series of fragments, according to the United States Geological Survey. These parts of the lithosphere are not stationary and move slowly. These are called “tectonic plates”.
As tectonic plates move and move past each other, they occasionally collide or collide. This puts stress on the edges of the plates. When the stress becomes too great, cracks called “flaws” are created. The point where these faults move against each other is called a “fault line”.
When there is too much friction between fault lines, energy is suddenly released, triggering seismic waves that lead to an earthquake.
What were the biggest earthquakes in California history?
California’s largest recorded earthquakes since 1800, ranked by magnitude, according to the California Department of Conservation.
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7.9: January 9, 1857 in Fort Tejon Two killed; scarred the surface 220 miles
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7.8: April 18, 1906 in San Francisco Possibly 3,000 dead; 225,000 displaced
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7.4: March 26, 1872 in Owens Valley. 27 dead; three replicas of magnitude >6
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7.4: 8 Nov 1980 just west of Eureka 6 injured; $2 million in damages
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7.3: July 21, 1952 in Kern County 12 killed; it included three magnitude-6-plus aftershocks in five days
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7.3: June 28, 1992 in Landers. One killed; 400 wounded; $9.1 million in damage
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7.2: 22 Jan 1923 in Mendocino. Damaged houses in several cities
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7.2: April 25, 1992 in Cape Mendocino. 356 injuries; $48.3 million in damage
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7.1: 4 Nov 1927 SW of Lompoc. No major injuries, light damage in two counties
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7.1 : 16 October 1999 in Ludlow. Minimal damage due to remote location
When is the next earthquake in California?
It is currently not possible to predict an earthquake, although USGS scientists can calculate “the probability that a significant earthquake will occur in a given area in a given number of years,” according to the USGS.
While earthquake forecasts and probabilities can be determined, the USGS says those reports are “comparable to climate probabilities and weather forecasts” and are not the same as predictions.
A USGS map of America reveals that portions of California face a greater than 95 percent chance of experiencing a minor or larger damaging earthquake within 100 years. In other words, a strong earthquake on the Modified Mercalli Intensity Scale that is “felt by all” will move some heavy furniture and cause minor damage.
No, California will not “fall into the ocean” due to earthquakes
Hours before Monday’s quake, the Berkeley Seismological Laboratory posted a thread about California and earthquakes saying it was fiction that California could eventually break off and fall into the ocean.
“This is because California earthquakes cause horizontal movement, not giant sinkholes or landfall into the sea,” the lab said on X. “No part of California is on a ‘margin’ that can break suddenly,” the lab said.
That means the state will not break away, sink or disappear into the Pacific. Earthquakes will continue in the lab he said, and the coastline will slowly change over millions of years, “but the land isn’t going anywhere suddenly.”
This article originally appeared on the Palm Springs Desert Sun: Recent quakes make ‘Big One’ more likely? What scientists say