Off the coast of northern California, on Thursday, Dec. 5, a magnitude 7.0 earthquake struck. Shortly after, a tsunami warning was issued for all areas along the coast of northern California and southern Oregon, though it was rescinded soon after . Residents of the impacted areas were told to evacuate amid rumors of the so-called “big one,” a cataclysmic earthquake and tsunami event.
Luckily, the magnitude 7.0 earthquake caused no deaths or immediate catastrophic damage to the affected area except for reports of items falling off store shelves and power going out for residents being the height of the problematic effects.
The most well-known fault line in California, the San Andreas, has perennially been rumored to be on the verge of bringing an earthquake event much like Japan’s 2011 Tōhoku earthquake and tsunami. However, this possibility is unlikely because according to the Richter scale, the maximum magnitude that the San Andreas can unleash is an 8.2, which is extremely powerful, but nowhere near the gravity of Japan’s 2011 tsunami event.
Concerns regarding the “big one” itself are not unfounded, however; about 300 miles off the coast of the Pacific Northwest, running along northern California, Oregon, Washington, and Vancouver Island, Canada, there is another fault line named the Cascadia Subduction Zone that poses a much more legitimate concern.
These ‘subduction zones’ are regions of the planet where the most harmful and devastating earthquakes have the seismic capability to occur at an apocalyptic degree, not capable by land-locked fault lines such as the San Andreas. Their name indicates that one tectonic plate slides underneath or subducts another plate. These regions are forecasted to produce a large earthquake event every 450 to 500 years.
Though Cascadia has remained undisturbed by such a disaster for years, seismologists say the plates are “locked” and rapidly building pressure.
Seismologists have been questioning if the smaller earthquakes are signs of the coming “big one.” When two tectonic plates subduct, it can cause one to curl up and slowly lift an entire continent by a few millimeters each year. Researchers believe an event called a full-margin rupture, a “big one”, is growing in probability because of the rate of potential subduction.
This motion has been observed and analyzed by the Yurok Tribe of California, who have foretold of a devastating earthquake and tsunami event by mapping out fault lines from their reservations along the California coastline for thousands of years.
For the first time in years, scientists are agreeing with them.
California residents need to turn their attention from the San Andreas fault line to the Cascadia subduction zone. Though the Dec. 5 earthquake was not the “big one” itself, or the result of seismic activity in the initially perceived “danger zone”, it is certainly a sign of it.
