Publication Date:
2015-05-07
Description:
Pre-existing networks of seismometers and continuous GPS in Northern Chile successfully captured surface motions and seismicity leading up to the April 1 st Mw 8.1. Here, we compare cGPS with predictions of seismic dislocations for the final foreshock swarm, beginning with the March 16 th Mw 6.7. Results show that the cumulative cGPS motion can be largely explained by seismic slip because evolutions of cGPS positions for most stations stay within the ranges of seismic predictions (given sensible ranges of assumed source errors). However, cGPS motions between 18 th -21st and 25 th- 31 st March outpace seismic predictions, supporting the existence of aseismic transients that were most probably the afterslip from preceding bursts of seismicity. A parameter search reveals that the March 16th Mw 6.7 cGPS displacements can be recreated with a fault plane significantly rotated anticlockwise from the strike of the plate interface, suggesting that failure was on a structure other than the plate interface.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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