On January 15, 1997, a landslide of approximately 100,000-m3 from a coastal bluff swept five cars of a freight train into Puget Sound at Woodway, Washington, USA, 25 km north of downtown Seattle. The landslide resulted from failure of a sequence of dense sands and hard silts of glacial and non-glacial origin, including the Lawton Clay, a hard, jointed clayey silt that rarely fails in natural slopes. Joints controlled ground-water seepage through the silt and break-up of the landslide mass. During September of 1997, the US Geological Survey began measuring rainfall, ground-water pressures, and slope movement at the bluff where the landslide occurred. Data are collected every 15 minutes and updated hourly on the World-Wide-Web. Pore pressures observed from September 1997 to February 1998 generally were low and pressures near the bluff face, in the upper few meters of the hard clayey silt, increased gradually.
Additional Publication Details
Real-time monitoring of bluff stability at Woodway, Washington, USA
Larger Work Title:
The geotechnics of hard soils - soft rocks. Proceedings of the second international symopsium on hard soils-soft rocks, Naples, October 1998. (Two volumes).
Number of Pages:
Proceedings of the second international symposium on hard soils-soft rocks 1998.