Scientists Keeping Keen Eye on Slow-Moving Alaskan Landslide That Could Trigger Devastating Tsunami
In 2023, researchers experienced a never-before-seen surface phenomenon that completely changed the way they perceived disaster monitoring. The phenomenon originated in Greenland's Dickson fjord and continued for nine days, according to Smithsonian Magazine. This observation led them to another long-brewing disaster in Alaska's Barry Arm fjord.
The signal from Dickson Fjord had never been observed before by scientists. "The seismic signal was something no one ever observed before," said Kristian Svennevig, a researcher at the Geological Survey of Denmark and Greenland who studied this strange signal. "This is a new natural phenomenon thrown at us by climate change." After examination, researchers understood that the signal was a result of Dickson Fjord's glacier thinning so much that it could no longer support the rock on top of it. The thinning ultimately led to the creation of a 650-foot-tall tsunami because of the rock falling into the water.
The signal continuing for nine days was a shock for scientists. "Had you suggested last summer if a wave could last for nine days in a fjord-like that, no one would have believed it," Svennevig said. "But it happened—we have to re-equilibrate our perception of what could happen because of climate change." Many similar tsunamis have now been observed by experts. To understand this new phenomenon, researchers have turned their attention to a fjord in Alaska called Barry Arm. This place is experiencing similar events that possibly happened in Dickson Fjord before the tsunami. Researchers want to analyze these events and better prepare for the future.
Researchers noted that a large portion of the fjord has been sliding for a long time, though they have been unable to pinpoint its exact start time. The portion that appears to be sliding is a finger-like structure, which is partially encased in ice. "It’s such a beautiful place in northwestern Prince William Sound … then you just have this nasty-looking slope hanging out there," said the U.S. Geological Survey’s (USGS) Dennis Staley, who’s worked on Barry Arm since 2021. "Once you know it’s there, it’s hard to not see it." The sliding piece was first spotted in 2019 by a tourist who was kayaking in the fjord.
After several research teams came on site, a multidisciplinary investigation started. Several scientists claimed that the structure had shifted around 600 feet from its original position from 2009 to 2015. Examinations have further claimed that if the structure does fall into the water, then the ensuing tsunami will destroy nearby communities as well as natural areas. One of the vulnerable towns is Whittier, which has around 260 inhabitants.
Several government organizations are regularly observing the shifting structure. Instruments like airborne lidar, remote cameras, airborne lidar and local seismometers are being used for the monitoring. Researchers are hopeful that regular monitoring will aid them in warning nearby communities of any disaster. The pursuit, though, is not easy by any means. "There are very few places to land a helicopter, you can’t hike up to it, there’s a tremendous amount of rockfall off the top, there are these massive tension cracks going across it," Staley says. "[We] installed a seismometer on the landslide itself … and it didn’t even last eight months … it was taken out by an avalanche in April."