Numerical Computation of Tsunami Response for Island Systems
A numerical procedure has been developed to determine the tsunami response of an island system and the surrounding underwater topography. The main algorithm is based on the Eulerian equations of motion and continuity which correspond to the classical, linear, longwave equation in the absence of friction and rotation. It performs an integration of these equations in terms of an explicit scheme based on centered differences. The computations are carried out on a Cartesian grid network and employ a condition of no normal flow at the island shoreline representation as well as an approximate radiation condition for the scattered portion of the wave field at the outer boundaries. The responses at the island shorelines are determined by introducing a time sequence input with a stipulated spectrum covering the tsunami range (490 min). Computations are continued for a duration sufficient to establish a statistical equilibrium within the system. The shoreline time series of water elevations are then Fourieranalyzed to obtain the spectrum for each point. Each spectrum is normalized by the spectrum of a time series taken of the forcing function, propagating on a grid of constant, deep water depth at a central position in the model. The normalized spectra or energy ratios are averaged for each island and for the entire set of shoreline points to produce the responses. The results are presented as graphs of averaged normalized spectra and as contours of (energy ratio)ﾽ on period vs island perimeter plots. An application of the technique is given for the Hawaiian Islands with a northern (Alaskan) wave approach angle. The results indicate energetic response is possible at ten periods from 12.5 to 73.1 min.
Simple
 Date ( Publication )
 19770101
 Status
 completed Completed
Point of contact
Bernard, Eddie N.
7600 Sand Point Way N.E.
,
Seattle
,
WA
,
98115
,
US
2065266800
 Maintenance and update frequency
 notPlanned Not planned
 Other ( Theme )

 North Pacific Ocean
 Metadata language
 engen
 Description
 Publication Date
N
S
E
W
 File identifier
 12abf5d07cf847109d9acf287d9320ef XML
 Metadata language
 engen
 Hierarchy level
 dataset Dataset
 Date stamp
 20010307
 Metadata standard name
 ISO 19139 Geographic Information  Metadata  Implementation Specification
 Metadata standard version
 2007
Point of contact
Kimberly Bahl
2065266485
NOAA / AFSC / PMEL, 7600 Sand Point Way N.E.
,
Seattle
,
WA
,
98115
,
US
2065264314
2065266485
Overviews
Spatial extent
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S
E
W
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