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Inversion of regional Pn1 and surface‐wave data for source parameters of a Borah Peak aftershock
Author(s) -
Patton Howard J.,
Doser Diane I.
Publication year - 1988
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/gl015i005p00459
Subject(s) - seismology , geology , aftershock , inversion (geology) , surface wave , seismic moment , seismic wave , magnitude (astronomy) , earth structure , dispersion (optics) , source model , epicenter , geodesy , fault (geology) , physics , computational physics , optics , astronomy , tectonics
We present results of a comparative source study on one of the largest aftershocks of the Borah Peak, Idaho, earthquake series. The mechanism of this event had been previously studied using first motions and teleseismic p‐wave data, and we report here our results from analysis of regional Pn1 and surface waves. The Pn1 waves gave an estimate of the source duration near 5 sec, in agreement with the teleseismic p‐waves. Both the source duration and the effect of surface‐wave dispersion through laterally heterogeneous crustal structures must be accounted for in the moment‐tensor inversions of intermediate period surface waves. All data sources, both long period and short, gave consistent source mechanisms, and the long periods also yield three independent and consistent estimates of the seismic moment. The results demonstrate the promise of formal source‐parameter retrieval techniques applied to regional data for the study of earthquakes with magnitudes below the magnitude threshold of teleseismic source determinations.