Open AccessThe tsunami mode of a flat earth and its excitation by earthquake sources
Author(s) -
Comer Robert P.
Publication year - 1984
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1984.tb01923.x
Subject(s) - geology , isotropy , tsunami earthquake , moment (physics) , excitation , mode (computer interface) , boundary value problem , geophysics , eigenfunction , point source , normal mode , moment tensor , seismology , mechanics , eigenvalues and eigenvectors , physics , classical mechanics , deformation (meteorology) , mathematical analysis , mathematics , vibration , oceanography , quantum mechanics , computer science , optics , operating system
Summary. Tsunami generation by earthquakes in a flat, isotropic, elastic, vertically stratified earth underlying a uniform‐depth, incompressible ocean can be studied in terms of the tsunami normal mode of the combined ocean‐solid earth system. We derive, in a way that demonstrates their natural extension from traditional approaches to tsunami theory, the equations and boundary conditions governing the tsunami mode displacement and stress eigenfunctions, then solve the excitation problem by a variational method. This leads to a straightforward expression for the far‐field tsunami displacements due to a point moment tensor source in the solid earth. Numerically computed spectra and waveforms reveal clearly the dependence of the far‐field tsunami on the source depth, duration, moment and mechanism.