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Effect of variable bathymetry on the amplitude of teleseismic tsunamis: A ray‐tracing experiment
Author(s) -
Woods Mark T.,
Okal Emile A.
Publication year - 1987
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl014i007p00765
Subject(s) - bathymetry , geology , ray tracing (physics) , seismology , amplitude , geodesy , shore , magnitude (astronomy) , tsunami earthquake , tsunami wave , waves and shallow water , geophysics , oceanography , optics , physics , astronomy
We apply surface wave ray‐tracing techniques to tsunami propagation in an ocean of variable depth. Because tsunami velocities are proportional to the square root of the depth of the water column, the juxtaposition of oceanic plateaux and basins generates strong lateral velocity gradients, and bathymetric features can act as lenses focusing or defocusing the tsunami waves. We present a reconstruction of the tsunami wave field from the great Chilean earthquake of 1960: an order‐of‐magnitude computation based on the concept of ray‐density provides qualitative agreement with observations at several sites in the Pacific Ocean. We also demonstrate the possibility of using “reciprocal” maps to identify tsunamigenic zones that present particular danger for a given receiving shore.