Earth and Planetary Science Letters, Volume 438, 15 March 2016, Pages 112–121
By Daniel S. Brothers, Peter J. Haeussler, Lee Liberty, David Finlayson, Eric Geist, Keith Labay, and Mike Byerly
“Highlights:
- New geophysical evidence for a large landslide complex offshore Chenega Island.
- Pervasive failure of glacimarine sediment along a perched sedimentary basin.
- Earthquake-triggered submarine landslides are likely cause of tsunami in 1964.
- Landslides display complex flow evolution from source area to deposition.
“During the 1964 Great Alaska earthquake (MwMw 9.2), several fjords, straits, and bays throughout southern Alaska experienced significant tsunami runup of localized, but unexplained origin. Dangerous Passage is a glacimarine fjord in western Prince William Sound, which experienced a tsunami that devastated the village of Chenega where 23 of 75 inhabitants were lost – the highest relative loss of any community during the earthquake. Previous studies suggested the source of the devastating tsunami was either from a local submarine landslide of unknown origin or from coseismic tectonic displacement. Here we present new observations from high-resolution multibeam bathymetry and seismic reflection surveys conducted in the waters adjacent to the village of Chenega. The seabed morphology and substrate architecture reveal a large submarine landslide complex in water depths of 120–360 m.
7.3-D perspective view of shaded relief bathymetry offshore Chenega village.
“Analysis of bathymetric change between 1957 and 2014 indicates the upper 20–50 m (
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