Starting Tuesday morning, more than 40 earthquakes have occurred along one of the most active fault lines in North America. Oregon And it continued until Wednesday, causing fear of a tsunami among the inhabitants of the Pacific Northwest.
Earthquake swarms ranged in magnitude from 3.5 to 5.8 and occurred in an area called the Blanco Fracture Zone, about 200 to 250 miles west of Newport on the Central Coast of Oregon. CaliforniaNotorious San Andreas Fault.
According to Oregon State University, the Blanco Fracture Zone has generated more than 1,500 earthquakes of magnitude 4.0 and above since the 1970s.
“If I asked me yesterday where on earth the most likely earthquakes of magnitude 5.0 and above would occur, this would have been at the top of my list,” said the Pacific Northwest Earthquake Network. Director Harold Tobin said. University of Washington CNN..
The National Meteorological Service tweeted about the massive seismic activity, but added that there was no risk of a tsunami because such a small amount of water was pushed away.
Photo: Plate system along the Pacific Ocean. More than 40 earthquakes occurred in 24 hours in the Blanco Fracture Zone.
Earthquake swarms ranging in magnitude from 3.5 to 5.8 occurred about 200 to 250 miles west of Newport, a city on the central coast of Oregon.
Photo: Harold Tobin, Director of the Pacific Northwest Seismic Network, University of Washington
At least nine tremors reached a magnitude of 5.0 to 5.8, most of which occurred at shallow depths.
according to USGS databaseSince 1980, the amount of earthquakes with a magnitude of 5.0 or more has been three times the annual average, that is, three earthquakes with a magnitude of 5.0 or more have occurred annually.
However, according to CNN, the US National Tsunami Warning Center reports that none of the more than 40 earthquakes this week have triggered tsunami warnings.
The National Meteorological Service also tweeted about the massive seismic activity, adding that there was no risk of a tsunami because the water moved very little.
Increased seismic activity in the region has raised concerns among residents of the Pacific Northwest. The region has already set a record for the largest earthquake in the Americas with a magnitude of 8.7-9.2 on January 26, 1700.
The National Weather Service PTWC helps monitor tsunamis in the area through the National Tsunami Warning Center.
Photo: Major subduction zone in the Pacific Northwest. There is a very active Blanca subduction zone and a Cascadia subduction zone.
The massive earthquake occurred in the nearby Cascadia subduction zone, causing a tsunami strong enough to hit both the west coast of North America and the coast of Japan.
The adjacent Cascadia subduction zone contains the Juan de Fuca plate, which submerges beneath the North American plate, which can cause catastrophic tsunamis and highly devastating tremors.
The Blanco Fracture Zone, which caused this week’s quake swarm, is one of the most active in North America, but it rarely causes fatal or catastrophic earthquakes.
The Blanco Fault is located about 275 miles west of Oregon and about 200 miles west of the Cascadia subduction zone from northern Vancouver Island, Canada to northern California.
“Earthquakes in the swing fracture zone are lateral displacements (lateral movements of the crustal blocks on both sides, not vertical displacements), so even a large earthquake is unlikely to pose a tsunami threat, for example magnitude. 7.0,’Tobin told the network.
Photo: Northwest Pacific Earthquake Network-Recent earthquakes, showing a series of earthquakes off Tuesday and Wednesday off Oregon.
Seismologist Dr. Lucy Jones told CNN that since 1980 there have been more than 133 earthquakes of magnitude 5 and above in the Blanco shatter zone, none of which have caused rupture on land.
“Today’s earthquakes can be thought of as a swarm of mainshocks and aftershocks, with the difference that the magnitude difference is not that great,” added Tobin.
Meanwhile, Tobin sought to mitigate the fear that this week’s quake could trigger the next “big quake.”
“There is a considerable distance from these earthquakes to the Cascadia subduction zone,” Tobin said.
“Current best understanding of how stress is transmitted through the crust (and mantle) suggests that these events do not significantly change the stress in the subduction zone.”
Over 40 earthquakes off the Pacific Northwest coast raises fears of a quake causing possible Tsunami Source link Over 40 earthquakes off the Pacific Northwest coast raises fears of a quake causing possible Tsunami