Starting on Tuesday and continuing into Wednesday, Dec. 9, more than 50 earthquakes shook the ocean floor off the Oregon coast. However, scientists believe that this shaking swarm poses little danger to people or property on land.
The U.S. Geological Survey estimates that 55 earthquakes have occurred as of midnight on Wednesday (Dec. 8), with the highest measuring 5.8 on the Richter scale.
The tremors occurred in the Blanco Fault Zone, an area frequently shaken by earthquakes of modest size.
As a result of its close vicinity to the Cascadia Subduction Zone, the Blanco Fault Zone is frequently viewed as a potential stress source for the Cascadia faults, which can generate massive earthquakes near the Oregon and Washington coastlines. However, experts claim this isn’t a risk.
Harold Tobin, the University of Washington’s head of the Pacific Northwest Seismic Network, responded, “There’s quite a lot of distance from these quakes to the Cascadia Subduction Zone. Our best current understanding of how stress transfers through the crust (and mantle) would suggest that these events don’t change stress on the subduction zone appreciably.”
The Blanco Fault Zone and the Cascadia Subduction Zone are 200 miles apart. The Juan de Fuca plate plunges beneath the North American plate at Cascadia.
Subduction is the scientific term for this motion, which can cause enormous, devasting earthquakes. Tsunamis can be generated by the crust moving up and down at subduction zones.
Compared to other fault zones, Blanco is a more forgiving one. It is located at the Juan de Fuca and Pacific plates intersection. It’s a strike-slip boundary or a transform fault zone. In other words, the plates move up and down very little as they slide past each other.
Additionally, the Blanco Fault Zone’s crust is relatively young and warm compared to the more fragile continental crust. Seismic waves travel less in more youthful, more amiable rock, which fractures more quickly in minor earthquakes.
Even the largest earthquakes at the Blanco Fault Zone don’t reach land because the fault zone is far enough offshore. Due to this, experts aren’t very concerned about the recent earthquake swarm.