We investigate a possible isotropic component in the source of the Bolivian earthquake of 09 June 1994 through a study of the radial modes pS0 (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 0S0, 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.
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)