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Radial modes from the great 1994 Bolivian earthquake: No evidence for an isotropic component to the source
Author(s) -
Okal Emile A.
Publication year - 1996
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 - 10.1029/96gl00375
Subject(s) - isotropy , physics , deep focus earthquake , excited state , seismology , excitation , geology , component (thermodynamics) , optics , atomic physics , subduction , quantum mechanics , tectonics , thermodynamics
We investigate a possible isotropic component in the source of the Bolivian earthquake of 09 June 1994 through a study of the radial modes p S 0 (p = 0, 1) excited by the event. Our study departs from previous similar attempts by making use of a time series of sufficient duration (over 116 days) to sample the shape of the spectral line of the fundamental radial mode 0 S 0 , and by combining measurements of two radial modes, thereby lifting the trade‐off between deviatoric and isotropic sources of excitation. Our result (an isotropic component of 0.5±1.3% of the main double‐couple) fails to identify a significant change in volume in the source of this, the largest deep earthquake ever recorded.