PROJECT: SKAGWAY DOCK SUBMARINE LANDSLIDE, Skagway, Alaska

Skagway Dock Submarine Landslide
Skagway Dock Following Failure

A massive submarine landslide destroyed a timber dock on the east shore of Skagway harbor. At the time, the dock was undergoing a $3.5 million reconstruction for large cruise ships. The landslide failed along the narrow shoreline, pulled 600 feet of the dock under water and scoured the harbor sediments to depths of 70 feet. A resultant wave damaged boats and docks in the harbor, requiring $2 million to repair the state's ferry terminal. One fatality occurred as a dock reconstruction worker was trapped and pulled below water.

Landslide Technology was retained by the Alaska Department of Transportation and Public Facilities to investigate the cause of the landslide. There was extensive review of reports, surveys and historic photographs. Five overwater borings were drilled in winter conditions, in water depths ranging from 80 to 210 feet with extreme tidal fluctuations of up to 20 feet, to collect samples and perform in-situ strength tests. The fieldwork, along with laboratory work and analyses of slope stability, provided information essential to ascertain what caused the slide. Expert testimony was provided to help determine liability.