Seismic study reveals hidden #megathrust #earthquake risk off #BritishColumbia

by Francesco Fiondella, Earth Institute at Columbia University
July 21, 2025

"A new study published in Science Advances has revealed the first detailed images of a newly developing #SubductionZone off the coast of British Columbia's Haida Gwaii archipelago.

"The international team of researchers collected the data for this study during a 2021 cruise by the Lamont-Doherty Earth Observatory's research vessel, the Marcus G. Langseth. They used a 15-kilometer-long underwater cable equipped with thousands of underwater microphones, called hydrophones, in the area off northern British Columbia to map the deep structure of Earth's subsurface.

"Their data confirmed that the #QueenCharlotteFaultSystem can generate powerful megathrust earthquakes, which are capable of producing strong shaking and #tsunamis.

"Megathrusts are found in areas where one tectonic plate dives beneath another, in this case the Pacific plate being pushed under the North American plate. This area is known for generating powerful tremors. In fact, the Queen Charlotte fault system represents the greatest seismic hazard in Canada, producing the country's largest recorded earthquake in 1949 and a notable earthquake in 2012 that created a tsunami.

" 'This region is actively becoming a subduction zone, so understanding the fault structure here tells us about the early stages of subduction zone development,' says lead author Collin Brandl, a postdoctoral research scientist at the Lamont-Doherty Earth Observatory, part of the Columbia Climate School.

" 'Our study provides the first direct observations of the Haida Gwaii thrust, the 'megathrust' of this system, which can help improve hazard analysis in the region, better preparing residents for future earthquakes and tsunamis.' "

Source:
https://phys.org/news/2025-07-seismic-reveals-hidden-megathrust-earthquake.html

All three mountains were out during my morning commute today. 🗻🗻🗻

#MtRainier #MountRainier #MtBaker #MountBaker #GlacierPeak #Tahoma #Kulshan #Dakobed #volcano #SubductionZone #Cascadia

#Cascadia #SubductionZone #earthquakes

"When an earthquake rips along the Cascadia Subduction Zone fault, much of the U.S. West Coast could shake violently for five minutes, and tsunami waves as tall as 100 feet could barrel toward shore. But that’s just the start of the expected horrors.

Even if coastal towns in Northern California, Oregon and Washington withstand that seismic onslaught, new research suggests, floodwaters could seep into many of these vulnerable communities for good. That’s because entire coastal shorelines are expected to drop by as much as 6½ feet when the earthquake strikes, according to new research published Monday in the Proceedings of the National Academy of Sciences."

https://www.nbcnews.com/science/earthquakes/cascadia-subduction-zone-earthquake-even-worse-feared-rcna203020

The West Coast Is at Risk: New Megathrust Fault Research Indicates That the Next Big Earthquake Could Be Imminent

https://scitechdaily.com/the-west-coast-is-at-risk-new-megathrust-fault-research-indicates-that-the-next-big-earthquake-could-be-imminent/

#earthquake
#Cascadia
#SubductionZone

What causes onshore faults to slip in subduction zones?

Well, it turns out that the commonly held reason does not apply to the faults located in northern Cascadia.

Read Harrichhausen et al. to find out why: https://seismica.library.mcgill.ca/article/view/1177

#cascadia #SubductionZone #Seismology #earthquakescience #peerreviewed #DiamondOpenAccess #earthquake #OpenAccess #OpenScience

The publications for the Cascadia Subduction Zone special issue are starting to come out, check them out here:
https://seismica.library.mcgill.ca/issue/view/91

Don’t miss out on contributing to this Seismica special issue!
Scope, topics, publication types, and conditions:
https://seismica.library.mcgill.ca/announcement/view/17

#cascadia #SubductionZone #OpenAccess #DiamondOpenAccess #peerreviewed #Seismology #earthquake #EarthquakeScience