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'The big one': Researchers gain clearest picture yet of fault that threatens the Pacific Northwest

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'The big one': Researchers gain clearest picture yet of fault that threatens the Pacific Northwest

A silent colossus lurks off the Pacific coast, threatening hundreds of miles of coastline with tsunamis and devastating earthquakes.

For decades, scientists have warned about the potential of the Cascadia Subduction Zone, a megathrust fault that runs offshore along the coast from northern Vancouver Island to Cape Mendocino, California. When the fault — or even a portion of it — next snaps, it will reshape life in Oregon, Washington and Northern California. 

Of particular concern are signals of massive earthquakes in the region’s geologic history. Many researchers have chased clues of the last “big one”: an 8.7-magnitude earthquake in 1700. They’ve pieced together the event’s history using centuries-old records of tsunamis, Native American oral histories, physical evidence in ghost forests drowned by saltwater and limited maps of the fault. 

But no one had mapped the fault structure comprehensively — until now. A study published Friday in the journal Science Advances describes data gathered during a 41-day research voyage in which a vessel trailed a miles-long cable along the fault to listen to the seafloor and piece together an image.

The team completed a detailed map of more than 550 miles of the subduction zone, down to the Oregon-California border.

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Their work will give modelers a sharper view of the possible impacts of a megathrust earthquake there — the term for a quake that occurs in a subduction zone, where one tectonic plate is thrust under another. It will also provide planners a closer, localized look at risks to communities along the Pacific Northwest coast and could help redefine earthquake building standards. 

“It’s like having coke-bottle glasses on and then you remove the glasses and you have the right prescription,” said Suzanne Carbotte, a lead author of the paper and a marine geophysicist and research professor at Columbia University’s Lamont-Doherty Earth Observatory. “We had a very fuzzy low-resolution view before.”

The scientists found that the subduction zone is much more complex than they previously understood: It is divided into four segments that the researchers believe could rupture independently of one another or together all at once. The segments have different types of rock and varying seismic characteristics — meaning some could be more dangerous than others. 

Earthquake and tsunami modelers are beginning to assess how the new data affects earthquake scenarios for the Pacific Northwest. 

Kelin Wang, a research scientist at the Geological Survey of Canada who was not involved in the study, said his team, which focuses on earthquake hazard and tsunami risk, is already using the data to inform projections. 

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“The accuracy and this resolution is truly unprecedented. And it’s an amazing data set,” said Wang, who is also an adjunct professor at the University of Victoria in British Columbia. “It just allows us to do a better job to assess the risk and have information for the building codes and zoning.” 

Harold Tobin, a co-author of the paper and the director of the Pacific Northwest Seismic Network, said that although the data will help fine-tune projections, it doesn’t change a tough-to-swallow reality of living in the Pacific Northwest.

“We have the potential for earthquakes and tsunamis as large as the biggest ones we’ve experienced on the planet,” said Tobin, who is also a University of Washington professor. “Cascadia seems capable of generating a magnitude 9 or a little smaller or a little bigger.” 

A quake that powerful could cause shaking that lasts about five minutes and generate tsunami waves up to 80 feet tall. It would damage well over half a million buildings, according to emergency planning documents. 

Neither Oregon nor Washington is sufficiently prepared.

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To map the subduction zone, researchers at sea performed active source seismic imaging, a technique that sends sound to the ocean floor and then processes the echoes that return. The method is often used for oil and gas exploration. 

They towed a 9-plus-mile-long cable, called a streamer, behind the boat, which used 1,200 hydrophones to capture returning echoes. 

“That gives us a picture of what the subsurface looks like,” Carbotte said.

The research vessel Marcus Langseth docks in Seattle after a 41-day expedition along the Pacific coastline. The ship allowed researchers to map the Cascadia Subduction Zone.Courtesy Harold Tobin

Trained marine mammal observers alerted the crew to any sign of whales or other animals; the sound generated with this kind of technology can be disruptive and harm marine creatures. 

Carbotte said the new research makes it more clear that the entire Cascadia fault might not rupture at once.  

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“The next earthquake that happens at Cascadia could be rupturing just one of these segments or it could be rupturing the whole margin,” Carbotte said, adding that several individual segments are thought to be capable of producing at least magnitude-8 earthquakes. 


Over the past century, scientists have only observed five magnitude-9.0 or higher earthquakes — all megathrust temblors like the one predicted for the Cascadia Subduction Zone. 

Scientists pieced together an understanding of the last such Cascadia quake, in 1700, in part via Japanese records of an unusual orphan tsunami that was not preceded by shaking there. 

“It requires an 8.7 to get a tsunami all the way to Japan,” Tobin said.

The people who recorded the incident in Japan couldn’t have known that the ground had shaken an ocean away, in the present-day United States. 

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Today, the Cascadia Subduction Zone remains eerily quiet. In other subduction zones, scientists often observe small earthquakes frequently, which makes the area easier to map, according to Carbotte. That’s not the case here. 

Scientists have a handful of theories about why: Wang said the zone may be becoming quieter as the fault accumulates stress. And now, we’re probably nearing due. 

“The recurrent interval for this subduction zone for big events is on the order of 500 years,” Wang said. “It’s hard to know exactly when it will happen, but certainly if you compare this to other subduction zones, it is quite late.”

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A dead woman’s key fob and two grisly crime scenes: How the Utah triple-murder suspect was tracked across state lines | CNN

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A dead woman’s key fob and two grisly crime scenes: How the Utah triple-murder suspect was tracked across state lines | CNN

As investigators raced to find the person responsible for three killings in rural Wayne County, Utah, they used automated license plate readers and a victim’s own vehicle key fob to track their suspect – a man police said has no connection to the victims or the region that is known for its awe-inspiring landscapes dotted with quiet, small towns.

It would take just hours to pin down the suspect in a search that spanned multiple states in the Four Corners region of the Southwest – ending early Thursday with the arrest of 22-year-old Iowa resident Ivan Miller, who is charged with three counts of first-degree, aggravated murder, officials said.

Miller was taken into custody in Colorado, officials said –– more than 350 miles from where the bodies of three women were found at two locations in Utah.

Miller’s first court appearance is scheduled for Friday afternoon in Archuleta County, Colorado. He will be represented by a public defender, court records show.

The victims were identified as Margaret Oldroyd, 86; Linda Dewey, 65; and Natalie Graves, 34, Utah’s Department of Public Safety said.

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Dewey and Graves, an aunt and niece who’d gone for a hike together, were found dead near a trailhead just outside the town of Torrey, Utah’s DPS said. The women’s bodies were found by their husbands who grew concerned when the pair didn’t return from their hike, Utah Highway Patrol spokesperson Lt. Cameron Roden said at a news conference Thursday.

Investigators found Oldroyd’s vehicle at the trailhead and deputies went to her home in nearby Lyman, where they discovered her body, Roden said.

After his arrest, Miller told investigators he spent a night in Oldroyd’s back shed and snuck into her house while she was out, according to an indictment filed in court Thursday. Miller “waited for her behind a door and shot her in the back of the head … while she was sitting down to watch television,” the indictment said.

Miller made efforts to clean up the scene before dragging the 86-year-old’s body to a cellar under the shed, where she was later found, the indictment read. He then stole her Buick Regal and traveled to the trailhead, investigators said. Miller told investigators “he did not like the car and wanted to find a different vehicle,” the indictment said.

At the trailhead, Miller said he saw Dewey and Graves get out of a white Subaru and shot them both, according to the indictment. Miller told investigators he stabbed one of the women in the chest multiple times because she was still moving, the document said.

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He then admitted dragging their bodies into a ditch, where the two were discovered by their husbands, the indictment said.

Officials said Miller ditched Oldroyd’s car at the trail and drove away in the white Subaru. Miller also admitted stealing the women’s credit cards and using one to pay for gas, according to documents.

Investigators used a network of license plate scanners to track the Subaru “through southern Utah into northern Arizona and eventually into Colorado,” Roden said.

“Colorado law enforcement located the vehicle abandoned in Pagosa Springs, Colorado, and after a brief search, took the individual into custody without incident,” Utah DPS said Thursday.

One of the husbands was also able to track the car’s location using an app that monitored the vehicle’s key fob, investigators said. Just after 9 p.m. Wednesday, the key fob appeared to be in Farmington, New Mexico — about two hours southwest of where Miller would later be taken into custody, according to the indictment.

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Miller had a handgun and a large knife in his possession at the time of his arrest, according to police in Pagosa Springs.

Miller told investigators he killed the women because he needed money, according to the indictment. “Miller confessed that it ‘had to be done’ but he did not like to do it,” the document reads.

Miller, who lived in Blakesburg, Iowa, set out on a cross-country road trip about two and a half weeks ago, his brother, who spoke with The New York Times on condition of anonymity, said.

Miller’s brother said the two stayed in contact during the trip, and Miller mentioned crashing his truck after hitting an elk, according to the Times.

The brother was concerned about how Miller was traveling around after that and offered to bring him back to Iowa, which he declined, the Times reported.

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After his arrest, Miller told officials that he had been staying at a hotel in the area for a few days after he hit an elk with his truck, which he then sold to a tow truck company, according to the indictment.

On Thursday, shaken residents across Wayne County placed pink ribbons around trees and fences in their communities as they remembered the three women who were killed in apparently random attacks carried out by a stranger.

“We wanted to honor our friend and neighbor,” Mary Sorenson, who put up ribbons around Lyman, told CNN affiliate KSL.

The Wayne County School District announced it would be closed for the rest of the week and would “have counselors in place to support students when we are back in session next week.”

In a statement Thursday, Torrey Mayor Mickey Wright described the multiple homicides as a “heartbreaking moment for our small, close‑knit community.”

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“Our community is strong. In the coming days, we will support one another, check on our neighbors, and ensure that those affected by this tragedy are not alone,” Wright said. “We stand together today — in grief, in compassion, and in solidarity.”

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Iran’s fight for survival / The widening war / Trump’s nebulous goals : Sources & Methods

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Iran’s fight for survival / The widening war / Trump’s nebulous goals : Sources & Methods
The U.S.-Israeli war with Iran is spilling out across the region. What are the goals? And how does it end?Host Mary Louise Kelly talks with International Correspondent Aya Batrawy, based in Dubai, and Pentagon correspondent Tom Bowman, about the U.S.-Israeli war with Iran. Six days of war have turned the middle east upside down, and it’s still not clear how the U.S. will determine when its objectives have been accomplished.Recommended Iran reading:Blackwave by Kim GhattasAll the Shah’s Men by Stephen KinzerPrisoner by Jason RezaianPersian Mirrors by Elaine SciolinoListener spy novel recommendation: Pariah by Dan FespermanEmail the show at sourcesandmethods@npr.orgNPR+ supporters hear every episode without sponsor messages and unlock access to our complete archive. Sign up at plus.npr.org.
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Map: 4.9-Magnitude Earthquake Shakes Louisiana

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Map: 4.9-Magnitude Earthquake Shakes Louisiana

Note: Map shows the area with a shake intensity of 4 or greater, which U.S.G.S. defines as “light,” though the earthquake may be felt outside the areas shown.  All times on the map are Central time. The New York Times

A light, 4.9-magnitude earthquake struck in Louisiana on Thursday, according to the United States Geological Survey.

The temblor happened at 5:30 a.m. Central time about 6 miles west of Edgefield, La., data from the agency shows.

U.S.G.S. data earlier reported that the magnitude was 4.4.

As seismologists review available data, they may revise the earthquake’s reported magnitude. Additional information collected about the earthquake may also prompt U.S.G.S. scientists to update the shake-severity map.

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Source: United States Geological Survey | Notes: Shaking categories are based on the Modified Mercalli Intensity scale. When aftershock data is available, the corresponding maps and charts include earthquakes within 100 miles and seven days of the initial quake. All times above are Central time. Shake data is as of Thursday, March 5 at 8:40 a.m. Eastern. Aftershocks data is as of Thursday, March 5 at 10:46 a.m. Eastern.

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