Large landslide strikes Pedersen Lagoon, Alaska generating 17 m (56 feet) high local tsunami, U.S.
Image credit: Lauren Schaefer (USGS)
A large landslide struck the Pedersen Lagoon in Alaska at around 12:55 UTC on August 7, 2024, generating a 17 m (56 feet) high local tsunami. The landslide was confirmed by aerial photos of the region from August 9. Preliminary data suggests a total volume of 2 million m3 (6.5 million feet3).
A large landslide hit Pedersen Lagoon, southwest of Seward, Alaska on August 7 at around 12:55 UTC, generating a tsunami approximately 17 m (56 feet) high in the Upper Pedersen Lagoon which reduced to roughly the height of 1 m (3 feet) in the lower region of the lagoon.
During the tsunami event, seismic signals suggest that a seiche, or an oscillating wave, likely formed.
The landslide took place in a rock unit called the Chugach flysch, which is composed of tectonically deformed and metamorphosed sandstone and siltstone that formed 145 to 66 million years ago.
The tsunami damaged wooden boardwalks at a lodge in the tidal zone and struck the National Park Service Campsite. Witnesses reported 0.6 to 0.9 m ( 2 to 3 feet) high waves flowing up the cabin. The tide reportedly ebbed at approximately 3 m (10 feet) during the incident.
Overflight photos of the location confirmed the occurrence on August 9. The runup heights are still preliminary and haven’t been validated yet. No injuries or fatalities have been reported relating to the incident.
Preliminary volume estimates based on seismic data indicate that the landslide was on the order of 2 million m3 (2.6 million cubic yards).
References:
1 2024 Pedersen Lagoon Landslide-Generated Tsunami – USGS -August 15, 2024
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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