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The fault line responsible for the quakes is the Blanco Fracture Zone.
One of North America’s most active fault lines sprung to life on Tuesday after a swarm of more than 40 earthquakes — ranging from a magnitude 3.5 to 5.8 — rattled off the coast of Oregon, catching the attention and concern of millions in the region.
The series of quakes, which began early Tuesday morning and continued into Wednesday, were all clustered between 200-250 miles west of the coastal town of Newport, OR, far enough to be mostly undetected on land, but given the area’s seismic history, it is creating quite a buzz.
“If you had asked me yesterday where on Earth would be most likely to produce a bunch of magnitude 5.0+ quakes in a single day, this would have been high on my list,” Harold Tobin, Director of the Pacific Northwest Seismic Network at the University of Washington, told CNN.
The fault line responsible for the quakes is the Blanco Fracture Zone. According to an analysis by Oregon State University, it is more active than the infamous San Andreas Fault in California, having produced more than 1,500 quakes of magnitude 4.0 or greater since the 1970s.
Not all quakes are created equal
What has been most impressive about this week’s quakes is the swarm has included at least 9 tremors reaching a magnitude 5.0 to 5.8, with the majority occurring at a shallow depth of only 10 km.
The sheer number of magnitude 5.0 or greater quakes in the region triples the annual average (three 5.0+ quakes per year) since 1980, according to the USGS database.
Fortunately, according to the US National Tsunami Warning Center, none of this week’s quakes have triggered a tsunami alert.
However, the activity has heightened the concern level for some, as the region is among the most earthquake-prone areas in North America and has already produced one of the largest quakes in the continental United States on January 26, 1700. The quake occurred on the neighboring Cascadia Subduction Zone, a megathrust fault much closer to land, where the Juan de Fuca plate dives underneath the North American Plate. This fault can not only trigger devastating tsunamis but also destructive shaking.
This is not necessarily a precursor for the so-called ‘big one’
Though the epicenter of this week’s swarm of quakes, the Blanco Fracture Zone, is among the most seismically active in North America, it rarely leads to destructive quakes.
The fault is some 275 miles west of the Oregon coastline and about 200 miles west of the Cascadia Subduction Zone, where the largest and most destructive Northwest quakes have historically taken place.
“Blanco Fracture zone quakes are strike-slip (lateral motions of the crustal blocks on either side, rather than up-down displacement), so it is very unlikely for them to pose a tsunami threat, even if a bigger quake happened, like a magnitude 7.0 for example,” Tobin told CNN.
According to seismologist Dr. Lucy Jones, there have been more than 133 quakes of magnitude 5 or greater on the Blanco Fracture Zone since 1980 and have never been followed by something on land.
“Today’s quakes can be thought of as something like a main-shock and a swarm of aftershocks, the one distinction being that in this case, there’s not a lot of magnitude difference among them,” Tobin said.
Though this week’s quakes have raised the concerns the so-called “big one” could be near, Tobin assured it is not necessarily the case.
“There’s quite a lot of distance from these quakes to the Cascadia Subduction Zone,” Tobin explained. “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.”
He pointed out, although we have had a remarkable number of magnitude 5.5+ quakes in a short period of time, it is not inherently alarming but rather seismologically interesting.
A similar swarm of quakes, though not to this week’s magnitude, occurred earlier this year near the Salton Sea in Southern California.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Canva
It might start as a disconcerting sensation of being slightly off-balance or the detection of an unusual rumbling. You might notice your pets acting erratically. Suddenly, it seems like the whole world is shaking: Books fall off shelves, furniture topples, windows shatter. Before you know it, the earthquake is over—leaving only destruction and devastation in its wake.
The lack of advance notice might be the scariest part about earthquakes: The United States Geological Survey’s early warning program can only alert you of an impending earthquake a few seconds to a minute ahead of time. Since you will have a brief instant to take cover (at most), it’s crucial to prepare your home and family for an earthquake ahead of time.
While taking these steps would be helpful for residents across the country, anyone who lives in one of the most earthquake-prone areas of the United States should pay particular notice to this plan. Seismologists and other scientists may not be able to predict when the “big one” will strike, but preparing yourself ]will give you some peace of mind. Stacker used resources from the Department of Homeland Security, the Federal Emergency Management Agency (FEMA), and other experts to compile a list of 15 ways you can prepare for an earthquake.
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Canva
It might start as a disconcerting sensation of being slightly off-balance or the detection of an unusual rumbling. You might notice your pets acting erratically. Suddenly, it seems like the whole world is shaking: Books fall off shelves, furniture topples, windows shatter. Before you know it, the earthquake is over—leaving only destruction and devastation in its wake.
The lack of advance notice might be the scariest part about earthquakes: The United States Geological Survey’s early warning program can only alert you of an impending earthquake a few seconds to a minute ahead of time. Since you will have a brief instant to take cover (at most), it’s crucial to prepare your home and family for an earthquake ahead of time.
While taking these steps would be helpful for residents across the country, anyone who lives in one of the most earthquake-prone areas of the United States should pay particular notice to this plan. Seismologists and other scientists may not be able to predict when the “big one” will strike, but preparing yourself ]will give you some peace of mind. Stacker used resources from the Department of Homeland Security, the Federal Emergency Management Agency (FEMA), and other experts to compile a list of 15 ways you can prepare for an earthquake.
You may also like: Natural disasters linked to climate change
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
igorfrontier // Shutterstock
Every person should have an emergency plan ready to go no matter where you live or what kind of natural disaster you’re most worried about. Sign up for emergency alerts and warnings in your area, decide where you will seek shelter, learn your evacuation route, and figure out how you will communicate with other members of your household in an emergency.
igorfrontier // Shutterstock
Every person should have an emergency plan ready to go no matter where you live or what kind of natural disaster you’re most worried about. Sign up for emergency alerts and warnings in your area, decide where you will seek shelter, learn your evacuation route, and figure out how you will communicate with other members of your household in an emergency.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Roger Brown Photography // Shutterstock
Every household should also have an emergency supply kit and go bags prepared for each person. That way, no matter what happens, you’ll have everything you need to survive a disaster.
Roger Brown Photography // Shutterstock
Every household should also have an emergency supply kit and go bags prepared for each person. That way, no matter what happens, you’ll have everything you need to survive a disaster.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Justin Sullivan // Getty Images
When you feel an earthquake, you immediately need to drop, cover, and hold. Drop down onto your hands and knees, crawl to shelter under a sturdy desk or table, and hold onto your shelter.
Justin Sullivan // Getty Images
When you feel an earthquake, you immediately need to drop, cover, and hold. Drop down onto your hands and knees, crawl to shelter under a sturdy desk or table, and hold onto your shelter.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Ollyy // Shutterstock
Taking cover under a strong table or desk could prevent you from getting hurt, but you might still be trapped underneath all kinds of debris. Practice signalling for help by knocking loudly or whistling so you can call out to rescuers in case you need assistance.
Ollyy // Shutterstock
Taking cover under a strong table or desk could prevent you from getting hurt, but you might still be trapped underneath all kinds of debris. Practice signalling for help by knocking loudly or whistling so you can call out to rescuers in case you need assistance.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Rama // Wikimedia Commons
Rama // Wikimedia Commons
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
KomootP // Shutterstock
During an earthquake, your home could slide off its foundation or even collapse. That’s not only dangerous but could cause hundreds of thousands of dollars in damage. A preventative retrofit, by contrast, can cost as little as $5,000 and potentially save your life.
KomootP // Shutterstock
During an earthquake, your home could slide off its foundation or even collapse. That’s not only dangerous but could cause hundreds of thousands of dollars in damage. A preventative retrofit, by contrast, can cost as little as $5,000 and potentially save your life.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Amanda Bicknell // Wikimedia Commons
Earthquakes can rip rigid gas lines from the walls, causing a gas leak that could lead to fire or explosion. Have flexible connection pipes installed to mitigate the risk.
Amanda Bicknell // Wikimedia Commons
Earthquakes can rip rigid gas lines from the walls, causing a gas leak that could lead to fire or explosion. Have flexible connection pipes installed to mitigate the risk.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Alexander Raths // Shutterstock
You might not be able to tell if your gas line breaks during an earthquake. Even if you can’t smell gas or see any exposed pipes, it’s best to shut off the gas immediately to be safe. Practice shutting off the line before an earthquake so you know exactly what you need to do in case of emergency.
Alexander Raths // Shutterstock
You might not be able to tell if your gas line breaks during an earthquake. Even if you can’t smell gas or see any exposed pipes, it’s best to shut off the gas immediately to be safe. Practice shutting off the line before an earthquake so you know exactly what you need to do in case of emergency.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
ALPA PROD // Shutterstock
Every home should have a fire extinguisher: You never know when you might need one. After an earthquake, you might have to put out a fire caused by a gas leak or downed power lines. Fire extinguishers should be in the kitchen and on every floor of a home.
ALPA PROD // Shutterstock
Every home should have a fire extinguisher: You never know when you might need one. After an earthquake, you might have to put out a fire caused by a gas leak or downed power lines. Fire extinguishers should be in the kitchen and on every floor of a home.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Andrey_Popov // Shutterstock
Think about the size of your refrigerator. Would you be able to lift it up by yourself? Probably not. Prevent any large appliances or pieces of furniture from coming loose during an earthquake by attaching them to the walls with nylon straps, heavy duty hooks or bolts.
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Andrey_Popov // Shutterstock
Think about the size of your refrigerator. Would you be able to lift it up by yourself? Probably not. Prevent any large appliances or pieces of furniture from coming loose during an earthquake by attaching them to the walls with nylon straps, heavy duty hooks or bolts.
You may also like: Major cities most at risk of rising sea levels
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Mattis // Wikimedia Commons
Child-safe latches will also keep you safe from falling dishes, pots, and pans during an earthquake.
Mattis // Wikimedia Commons
Child-safe latches will also keep you safe from falling dishes, pots, and pans during an earthquake.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Undrey // Shutterstock
Search your home for anything else that could fall during an earthquake, such as artwork, light fixtures, and vases. Attach them to walls or tables with museum wax or earthquake putty.
Undrey // Shutterstock
Search your home for anything else that could fall during an earthquake, such as artwork, light fixtures, and vases. Attach them to walls or tables with museum wax or earthquake putty.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
gpointstudio // Shutterstock
If possible, move your bed away from any windows. Earthquakes can break the windows, causing a shower of broken glass to fall on top of you. It’s also not a good idea to hang heavy frames or shelves above your bed for this reason.
gpointstudio // Shutterstock
If possible, move your bed away from any windows. Earthquakes can break the windows, causing a shower of broken glass to fall on top of you. It’s also not a good idea to hang heavy frames or shelves above your bed for this reason.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
Mix Tape // Shutterstock
Powerful earthquakes can knock out both power and cell service for hours or days. If you usually rely on Google Maps to get around town, you’ll be out of luck. Download maps of your area for online access or purchase paper copies of local maps.
Mix Tape // Shutterstock
Powerful earthquakes can knock out both power and cell service for hours or days. If you usually rely on Google Maps to get around town, you’ll be out of luck. Download maps of your area for online access or purchase paper copies of local maps.
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A swarm of more than 40 earthquakes in 24 hours is causing a buzz in the northwest US
KorArkaR // Shutterstock
Typical homeowner insurance policies don’t cover damage from earthquakes. If you live in a particularly earthquake-prone area, you might want to consider purchasing additional earthquake insurance to help you repair your home more quickly after a disaster.
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KorArkaR // Shutterstock
Typical homeowner insurance policies don’t cover damage from earthquakes. If you live in a particularly earthquake-prone area, you might want to consider purchasing additional earthquake insurance to help you repair your home more quickly after a disaster.
You may also like: 30 of the most devastating hailstorms in US history
