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Varieties of submarine failure morphologies of seismically-induced landslides in Alaskan fjords

January 1, 2006

The Great Alaska Earthquake of 1964 caused major damage and 43 deaths in the coastal communities of Seward and Valdez. Most of these losses were caused by tsunamis that occurred immediately after the earthquake and were most likely induced by local submarine landslides. Recent NOAA multibcam bathymetric surveys near Seward and Valdez provide detailed information about the morphology of landslide deposits in both areas. High-resolution (chirp) surveys were conducted by the USGS, and sediment samples were taken over apparent landslide debris. Landslide deposits near Seward typically take the form of a series of large and small blocks lying directly off the front of the town, although there are indications of sandy and muddy debris flows occurring off river deltas. Near Valdez, landslide morphologies include at least three forms: a field of large blocks (up to 40 m high), an intricate series of gullies, channels, and talus near the fjord-head delta and a broad debris lobe that apparently flowed half-way down the fjord and stopped. The 1964 landslide tsunamis may have been composites resulting from a number of landslide events.

Publication Year 2006
Title Varieties of submarine failure morphologies of seismically-induced landslides in Alaskan fjords
Authors H. Lee, H. Ryan, R. E. Kayen, Peter J. Haeussler, P. Dartnell, M. A. Hampton
Publication Type Conference Paper
Publication Subtype Conference Paper
Index ID 70028701
Record Source USGS Publications Warehouse
USGS Organization Alaska Science Center