Title

The effects of basal resistance and hydroplaning on the initial kinematics of seismically induced tsunamigenic landslides

Document Type

Conference Proceeding

Date of Original Version

12-1-2008

Abstract

According to current landslide tsunami generation models, the initial acceleration time history of a submarine mass failure is an important factor influencing the source characteristics of tsunami waves. Translational models developed thus far typically simulate rigid or deforming bodies sliding down an inclined plane, assuming either negligible basal resistance or an idealized basal resistance, with or without the inclusion of hydrodynamic forces. However no known models incorporate realistic basal resistance, hydrodynamic forces, and hydroplaning together to quantify their effects on the initial kinematics of submarine failures. In all current models it is assumed that the maximum initial acceleration occurs nearly instantaneously after the moment of failure. Here, we propose a new rigid body model that incorporates hydrodynamic drag, with realistic basal resistance and hydroplaning effects. Utilizing the post failure shear strength of the sediment, this new model investigates the initial kinematics and time histories of the slide event in relation to tsunami generation over varying slope angles and idealized hydroplaning conditions. The current work is restricted to seismically induced submarine landslides in normally consolidated clay. The modeling results indicate a decrease in the magnitude of the peak slide acceleration by 27% to 47% and significant delays in the acceleration time histories of the sliding mass. The results also show an exponential increase in the delay of the acceleration time histories as the slope angle decreases, suggesting a greater influence of basal resistance and hydroplaning effects on typical submarine failures, for slopes of less than 5°. Further research is necessary to determine the influence of using the refined basal resistance models on predicted initial landslide tsunamis wave heights, lengths, and subsequent costal run-up elevations. Copyright ASCE 2008.

Publication Title

Geotechnical Special Publication

Issue

178

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