Eighty years ago, a massive tsunami devastated parts of Hawaii, Alaska, Washington and Oregon following an earthquake off the coast of Alaska. A Michigan State University team is launching a project to study the underwater fault system where it originated – and whether it still poses a risk today.
Songqiao “Shawn” Wei, associate professor of earth and environmental sciences as well as computational mathematics, science and engineering, is gearing up for an expedition to measure vibrations of tectonic plates in the Alaskan-Aleutian subduction zone.
For this project, Wei’s team will place waterproof sensors called seismometers at the bottom of the Pacific Ocean near Alaska. They’ll use atomic clocks to accurately time each vibration they record. A battery will power the sensor for 15 months, at which point Wei’s team will collect them to analyze the data.
A project of this magnitude takes more money and planning than tracking vibrations on land. That’s where a National Science Foundation grant comes in.
MSU is partnering with the University of Hawaii in the first NSF award of its kind since January 2025. They’re also receiving ship time and instrument usage for the project.
Wei is studying this area because the 1946 tsunami was caused by a relatively small earthquake there. How this happened is still a mystery to seismologists.
While the sensors can’t tell researchers what happened 80 years ago, they can reveal how the fault is behaving today and help scientists assess whether the region could produce another earthquake or tsunami.
“We are still far from predicting earthquakes,” Wei said. “But we can improve our understanding of this local region, and that will be incorporated by the U.S. Geological Survey’s risk map and then into building codes.”
Tracking energy
Earthquakes happen when tectonic plates, which move along faults in the Earth’s lithosphere, get stuck against each other, building up pressure until they suddenly slip. This releases energy that shakes the ground.
Seismologists – researchers who study earthquakes – can use this energy to image the Earth’s interior. Tracking this data is critical for understanding why earthquakes happen, but collecting it is a matter of being in the right place at the right time.
That’s why Wei places seismometers in known earthquake hot spots like Samoa, Alaska and the Marianas and keeps them there for months or years.
Over time, the seismometers record every vibration so that Wei can analyze the data once the sensors are collected.
Faults on land are much easier to study. Typically, seismometers track vibrations for years, thanks to solar panels that keep their batteries charged. Scientists can also rely on global positioning systems, or GPS, for precise location and timing. Neither GPS nor solar power is available to instruments sitting deep underwater.
“Logistically, it’s very expensive and challenging to go to those places,” Wei said.
Before a ship ever leaves the harbor, Wei and his team map the ocean floor and find the best location for each seismometer, looking for a smooth, flat spot without rocks. Then, once it’s time to deploy, they use a floatation system to ensure the sensor drops slowly enough that it isn’t damaged by the fall. Just dropping one sensor can take hours.
The effort is necessary to understand tsunami risks. When an undersea earthquake suddenly raises or lowers the ocean floor, it displaces the water above it. That disturbance travels across the ocean as a tsunami, growing taller as it reaches shallow coastal waters.
Wei’s sensors will help the team understand how the Pacific and North American plates are interacting today and what that could mean for future earthquake risk.
New frontiers to discover
He’s also interested in a phenomenon called slow earthquakes. Over the past few decades, scientists have discovered that sometimes, fault movements unfold over days or weeks instead of a few seconds. This allows the plates to slowly release energy without the violent shaking of a typical earthquake.
Wei wants to know if slow earthquakes are related to the unusual 1946 earthquake and tsunami, and why they seem to be localized to this part of the Aleutian subduction zone.
The seismic data will also allow Wei to peer beneath the seafloor, much like a CAT scan uses waves to see inside the human body. He’s particularly interested in water trapped deep within the Earth and whether it changes the friction between tectonic plates, potentially influencing whether a rupture stops or grows into a major earthquake.
Wei’s team hopes they will launch their next research cruise in 2028, leaving the instruments on the ocean floor for about 15 months. What they record could help answer questions at the frontier of earthquake science: Why does one earthquake rupturing stop, while another keeps going? Why do some earthquakes slip slower, while others rupture quickly and violently?
Those questions can’t be answered in a lab simulation.
“For us, nature is the lab,” Wei said. “We need to go to those places. And it turns out Earth is always way more complicated than our human labs. There are always surprising discoveries.”