Open AccessTheoretical Seismograms for the Colombian Earthquake of 1970 July 31
Author(s) -
Luh Peter C.,
Dziewonski Adam M.
Publication year - 1975
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.1975.tb06187.x
Subject(s) - seismogram , moment tensor , seismology , geology , computation , amplitude , moment (physics) , range (aeronautics) , geodesy , earth structure , seismic moment , focal mechanism , kinematics , geophysics , physics , mathematics , fault (geology) , algorithm , classical mechanics , oceanography , deformation (meteorology) , materials science , quantum mechanics , composite material
Summary Using Gilbert & Dziewonski's retrieved structural parameters, Earth model 1066A, their Q μ ( r ) model, and the moment rate tensor for the Colombian earthquake of 1970 July 31, we produce 75 theoretical seismograms in epicentral co‐ordinates by superimposing all the normal modes (1105 modes) within a period range from 100.1 to 963.8 s. The computed seismograms are compared with the respective observed ones. Such a comparison is possible not only because all the modes in the frequency range are taken into account in the computation, but also because we have a realistic kinematic source mechanism at our disposal. A qualitative, though far from exact, reproduction of actual seismograms was successfully effected, indicating the moment rate tensor represents a reasonable source model for the Colombian earthquake. In particular, on the average we are able to reproduce the observed amplitudes to within 30 per cent. Among surface and body‐wave phases identified, multiple S ‐waves can be identified up to 21 S at almost 8 h after the origin time on both the observed and computed co‐latitudinal record sections.