Could Recent Cascadia Earthquakes in California Herald "The Big One," Long Overdue Catastrophic Seismic Activity?

Recent Cascadia Earthquakes felt in California have sparked discussions and speculation that they may be the precursor to the long-overdue catastrophic seismic activity known as "the Big One."

Some claim that the recent earthquakes that shook Northern California are stark warnings of even stronger ones to come. Experts from different universities discuss this claim.

Recent Cascadia Earthquakes, California

The US Geological Survey reported that a 5.4 magnitude earthquake struck parts of Rio Dell (Humboldt County) at 10:30 AM on January 1, New Year's Day. A few people were left without water, and half of the locals lacked electricity.

Authorities have reassured locals that there have been no reported injuries and that there are no foreseeable risks associated with the earthquake, such as a tsunami.

Only two weeks had passed since the area was shaken by an earthquake of magnitude 6.4 on December 19. Numerous power outages and at least two reported fatalities were the results.

Speculations: Long Overdue Catastrophic Earthquake

Due to the area's extreme tectonic activity, earthquakes are not uncommon in the area. The area is the most seismically active in the lower 48 states, but some people believe a devastating earthquake that could cause a tsunami has been overdue in the area.

This is due to the fact that it is situated at the southern end of the Cascadia subduction zone, where the US is direct atop the ocean floor. The San Andreas Fault, which forms the boundary between two enormous tectonic plates beneath the surface of the Earth, has the fault located at its northernmost point.

Since these plates are stationary, they can sustain sustained high pressures. When they do move, they have the potential to cause devastating earthquakes of enormous size. This fault has the potential to cause earthquakes with magnitudes of 8 or 9. This magnitude of earthquakes can also cause tsunamis. A "Big One" is long overdue in the Cascadia region, where an earthquake and tsunami last occurred on January 26, 1700.

The magnitude of this hypothetical occurrence would be comparable to the 9.1 earthquake and tsunami that struck Tōhoku, Japan, in 2011.

What Experts Say

But according to experts, this most recent earthquake is not yet a precursor to something else.

Alex Simms, a professor at the University of California, Santa Barbara, told Newsweek that this is typical; it is most likely an aftershock or perhaps another earthquake on a nearby fault, but he doesn't believe anything else is going on.

Aftershocks from the earthquake that occurred on December 19 have been felt all over the region. Over time, their magnitude typically gets smaller.

Harold Tobin, a professor at the University of Washington and Paros Endowed Chair in Seismology and Geohazards, also said that since aftershocks follow nearly all earthquakes, this one is most likely one of them.

The US Geological Survey predicted that the likelihood of aftershocks with a magnitude of 5 or higher within the first week after the first earthquake on December 19 was extremely low.

According to the Government of Canada, a megathrust earthquake's recurrence interval varies in every subduction zone. 13 megathrust events, or one every 500 to 600 years on average, have been recorded in the Cascadia subduction zone over the past 6,000 years. They have not, however, occurred frequently; some have occurred 200 years apart, while others have occurred 800 years apart. Still, it is worth noting that the last one happened 300 years ago.

Read also: 11 Earthquakes Rattle Illinois to Arkansas, Experts on the Lookout for Next Possible Strong Seismic Activity in Eastern US 

Continuous Monitoring

Seismologists continue to keep a watchful eye on the Cascadia subduction fault even though the most recent earthquake did not cause alarm.

Tobin advises residents of this area to always be ready for both a tsunami and a larger, more destructive earthquake. There is a chance that there will be earthquakes in the future, but seismologists are not yet able to predict an earthquake's precise time or location, down to a specific year or decade. There is currently no telltale precursor that we can detect, but experts are working hard to find one.

We can measure the signals that indicate the stress and strain that will eventually lead to the next one building up. The next one could be a magnitude 8 or 9 earthquake with a tsunami that traverses the entire Pacific and also washes up on nearby shores, Newsweek reports.

According to the Oregon Department of Emergency Management, according to current estimates, there is a 37% chance that this fault zone will experience a megathrust earthquake with a magnitude of 7.1 or higher within the next 50 years and will be felt throughout the Pacific Northwest.

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