HR: 1330h
AN: OS22B-1158    [PDF]
TI: Modeling and Experimental Validation for Tsunamis Generated by Submarine Mass Failure
AU: * Enet, F
EM: enet@oce.uri.edu
AF: Department of Ocean Engineering, University of Rhode Island, Narragansett, RI 02882 United States
AU: Grilli, S T
EM: grilli@oce.uri.edu
AF: Department of Ocean Engineering, University of Rhode Island, Narragansett, RI 02882 United States
AU: Watts, P
EM: phil.watts@appliedfluids.com
AF: Applied FLuids Engineering Inc., PMB \#237, 5710 E 7th Street, Long Beach, CA 90803 United States
AU: Kirby, J T
EM: kirby@udel.edu
AF: Center for Applied Coastal Research, University of Delaware, Newark, DE 19716 United States
AB: Numerical models of tsunamis generation by Submarine Mass Failure (SMF) were developed in earlier work by the authors. More recently, this included a three-dimensional (3D) SMF tsunami source model, based on Fully Nonlinear Potential Flow equations (FNPF) (Grilli et al., 2002), and the integration of this model into a Boussinesq wave propagation and runup model (Watts et al., 2003a). The combined model for SMF tsunami generation, propagation, and runup, referred to as GEOWAVE, was successfully applied to a number of case studies, including PNG 1998, Skagway 1994, and Unimak 1946 (e.g., Watts et al., 2003ab). In the present work, we first describe recent improvements made to the model components of GEOWAVE, and their application to historical case studies. One recent addition to the Boussinesq propagation model, in particular, is its implementation in spherical coordinates, which allows using it over larger scale tsunami propagation areas. This is useful to study both transoceanic SMF tsunami near- and far-field propagation within the same dispersive long wave model. Second, we report results of recent large scale three-dimensional experiments performed at the University of Rhode Island, to investigate tsunami generation by underwater landslides. Each experiment consists of a solid landslide of idealized smooth shape sliding over a plane slope. Surface elevations are measured using capacitance gages placed at strategic locations. Gage calibration is performed using a newly developed automated system. Runup at the shoreline is measured using a remotely operated digital camera. Landslide acceleration is measured with a micro-accelerometer embedded at the landslide center of mass and an optical system also measures landslide displacement, as a way of cross-validation. The repeatability of experiments is first investigated, and then by varying the initial depth of the landslide, different conditions of wave non-linearity and dispersion are generated and compared. Third, we present the comparison of these recent experiments with results of the 3D-FNPF model mentioned above. The agreement of computations with experiments is quite good for surface elevation. Model results can thus be analyzed to gain insight into the physics of SMF tsunami generation. For instance, in the model, horizontal velocities are found to be quite non-uniform over depth above the moving landslide. Further away from the landslide, however, horizontal velocities become quite uniform over depth, as would be expected for a long wave. {\bf References:} Grilli, S.T., Vogelmann, S. and Watts, P. 2002 Development of a 3D Numerical Wave Tank for modeling tsunami generation by underwater landslides. {\it Engineering Analysis with Boundary Element}, {\bf 26}(4), 301-313. Watts, S. T. Grilli, J. T. Kirby, G. J. Fryer, and Tappin, D. R. 2003a. Landslide tsunami case studies using a Boussinesq model and a fully nonlinear tsunami generation model. {\it Natural Hazards and Earth System Sciences, EGS}, {\bf 3}, 1-12. Watts, S. T. Grilli and J. T. Kirby 2003b. Tsunami warning opportunities at Skagway, Alaska based on water wave records. {\it J. Science Tsunami Hazards} (accepted).
UR: http://www.oce.uri.edu/~grilli
DE: 4255 Numerical modeling
DE: 4564 Tsunamis and storm surges
DE: 7223 Seismic hazard assessment and prediction
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting