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| Titel |
Search for repeating events at the plate interface in the seismic sequence of the 2014 Mw8.1 Iquique earthquake, Chile |
| VerfasserIn |
Joern Kummerow, Günter Asch, Christoph Sens-Schönfelder, Bernd Schurr, Frederik Tilmann, Serge A. Shapiro |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250149591
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| Publikation (Nr.) |
 EGU/EGU2017-13953.pdf |
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| Zusammenfassung |
| The 2014 Mw8.1 Iquique earthquake occurred along a segment of the northern Chile-
southern Peru seismic gap which had not ruptured for more than 100 years. A specific feature
of this event is the observation of prominent foreshock clusters with successively increasing
seismic moment releases starting several months before the main shock (e.g., Schurr et al.,
2014). The entire seismic sequence, including also the aftershock seismicity, was
monitored exceptionally well by the Integrated Plate Boundary Observatory Chile
(IPOC).
Here, we present results from a systematic, long-term search for repeating seismic
events along the plate interface in the source region of the 1 April 2014 (Mw8.1)
Iquique main shock. Repeating earthquakes are widely assumed to indicate recurrent
ruptures on the same fault patch and to accommodate aseismic slip in the creeping
portions around the seismic patch. According to this concept, the analysis of repeating
events and of their temporal behaviour provides a tool to estimate the amount of
creep.
We use the IPOC and two additional local seismic networks and select recorded waveforms
of several hundreds of located earthquakes within the foreshock and aftershock series as
template events. Waveforms are windowed around the P and S phases and bandpass-filtered
for different frequency bands. Window starts are defined by manually revised P onset times.
We then run a newly implemented correlation detector on the resampled, continuous
seismic data to find highly similar waveforms for each template event. Repeating
earthquakes are finally identified by a combination of estimated source dimensions, high
waveform similarity and precise relative relocations of the events within each multiplet
group.
The analysis of the spatial and temporal patterns of the detected repeating earthquake
sequences allows to test the proposed idea of progressive unlocking of the plate boundary
before the Iquique main shock. |
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