More than 50 earthquakes rock US northwest in 24 hours

WHAT YOU NEED TO KNOW:

• The earthquakes occurred along Oregon’s coast within an area called the Blanco Fracture Zone.
• Experts say the Blanco Fracture Zone is one of the most active earthquake areas near North America.
• The Pacific Northwest Seismic Network said there have been 49 earthquakes above magnitude 4.5 in the area in the last five years alone.

Oregon was swarmed with more than 50 earthquakes all ranging in magnitude this week. Experts say the seismic activity is not alarming.

On Tuesday, the National Weather Service announced that there had been a “swarm” of earthquakes off the Oregon coast with the strongest one recorded at 5.8 magnitude. The earthquakes were considered common in that area, the agency added. Since little water was displaced, no risk of a tsunami was announced.

Reports say the earthquakes began Tuesday afternoon with the strongest two earthquakes — with magnitudes 5.3 and 5.5 — occurred around 1:30 p.m. and 2 p.m. Two more magnitude 5.0 and 5.8 quakes hit several hours later. Another 5.8 quake occurred just before 5:30 p.m., and multiple smaller aftershocks continued into the evening. 

The series of earthquakes occurred on the Blanco Fracture Zone. According to the Pacific Northwest Seismic Network (PNSN), it has a long history of being the most active earthquake area near North America. There have been 49 earthquakes above magnitude 4.5 in the area in the last five years alone.

Oregon is close to moving fault lines, specifically, the Cascadia Subduction Zone, which is a 600-mile fault line that runs from northern California up to Canada. 

Since Oregon is located in the middle of the Cascadia Subduction Zone, it has the potential for a 9.0+ magnitude earthquake and a tsunami of up to 100 feet high.

Experts believe Oregon is not at risk for serious earthquakes. Scientists predict that there’s about a 37 percent chance that an earthquake of 7.1+ magnitude would shake the state in the next 50 years. 

Oregon is preparing though, using ShakeAlert, a service created by the United States Geological Survey (USGS) to give people a few seconds heads up that an earthquake is happening and that shaking is imminent.

The ShakeAlert system is made up of a network of sensors that share information about the magnitude, location and expected shaking from earthquakes along the West Coast. The program serves not just Oregon, but California and Washington state.

Source: The Hill