State of the Planet

News from the Columbia Climate School

Searching for the Megathrust Fault at Cascadia

We are under way on our nearly six-week-long expedition, traveling along the coast of Oregon to British Columbia to investigate the Cascadia Subduction Zone. This subduction zone has been the site of past “megathrust” earthquakes, which are the largest earthquakes that happen on Earth, but is eerily quiet at present, with little seismicity detected within the Oregon to Washington portion. Scientists believe this lack of seismicity reflects the “locked” state of the megathrust fault at present, with stress quietly accumulating as the Juan de Fuca plate system continues to dive (subduct) beneath North America. All or part of that built-up stress will eventually be released in the next great earthquake.

Little is known about the properties or even the location of the portion of the fault zone that generates the large destructive earthquakes. During our cruise, we are using sound to probe under the seafloor looking for the megathrust fault deep beneath several kilometers of sediments that cover the down-going Juan de Fuca plate. Our survey, which is funded by the National Science Foundation,  will be the first-ever seismic imaging study to span almost the entire Cascadia subduction zone. We will be using modern advanced seismic imaging technology to detect and characterize fine-scale structures within the subduction zone to help address a range of scientific questions pertaining to earthquake and tsunami hazards within the Pacific Northwest region. 

For our investigation we are making use of Columbia University’s R/V Marcus G. Langseth, one of the large global-class research vessels within the NSF-supported Academic Research Fleet. The Langseth is a unique ship within the research fleet, equipped for advanced seismic imaging, with a high-quality sound source and capable of towing an array of listening devices called hydrophones up to 15 kilometers long behind the ship to listen to the echoes returned from the seafloor and deep below.

diagram
Top: A diagram of the Cascadia Fault, with the Juan de Fuca plate sliding under the North American plate. The red arrows point to the potential areas that may be responsible for the fault’s largest earthquakes. Bottom: A diagram showing the ship’s sound emitters and sound waves bouncing off of different layers below the seafloor. A streamer of hydrophones towed behind the ship listens for these echoes.

We have a terrific team onboard of scientists and students from Columbia University, University of Texas Institute for Geophysics, Woods Hole Oceanographic Institution, University of Washington, and Oregon State University/NOAA. We also have expert science technicians who operate the advanced seismic equipment and teach us along the way, marine mammal observers who let us know when marine mammals are nearby so that we don’t bother them with our sound equipment, and the Langseth’s most capable officers and crew who ensure the conduct of our survey and the safe operation of our ship. For most of us this is our first time with a group of people outside our “bubbles” since the pandemic began, and we are thrilled to be together underway on this expedition.

Columbia campus skyline with text Columbia Climate School Class Day 2024 - Congratulations Graduates

Congratulations to our Columbia Climate School MA in Climate & Society Class of 2024! Learn about our May 10 Class Day celebration. #ColumbiaClimate2024

Subscribe
Notify of
guest

4 Comments
Oldest
Newest
Inline Feedbacks
View all comments
Shaun Shaver
Shaun Shaver
2 years ago

It’s been a very interesting cruise so far with it’s ups and downs. We have acquired 3700km of data to date and with just over 9 days to go we are hoping to collect much more valuable data for Suzanne and the world !!

Leighton Wells
Leighton Wells
2 years ago

Exciting project, and a great research design!
Glad WHOI alerted its members to your work.
When you get to interpreting things, (if the data lends itself to interpretation) I’ll mention your doings to my. local (Eugene OR) natural history society.

Leighton Wells

Dominique Miller
Dominique Miller
2 years ago

Gosh I wish I could come with. This is so interesting to me! Alas, I am a lowly podcaster and author who just so happens to find the Cascadia Subduction Zone and the inevitable megathrust quake to be a fascinating topic to write about, research, and dicuss. I’ve always been so interested in some of the accounts of people living in Japan when the tsunami hit, some three hundred twenty years ago, and I enjoy reading the Qulieute tales of the Thunderbird and Whale. It would be so great to know exactly where the quake will originate from, along the subduction zone where the Juan de Fuca plate is subducting beneath the North American plate. Best of luck! Thanks so much, however, for keeing us all updated!

Last edited 2 years ago by Dominique Miller
Madeleine Lucas
Madeleine Lucas
Reply to  Dominique Miller
2 years ago

Hi Dominique! If you’d ever like to discuss the CASIE21 cruise and the Cascadia Subduction Zone in general, I’d love to chat! I was part of the science party on board the Langseth. I find these topics so interesting that I often spend my little free time from working on my PhD learning more about earthquake and tsunamis… 🙂

Last edited 2 years ago by Madeleine Lucas