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| Titel |
Segmentation of Seismicity in the Mejillones Region, Northern Chile |
| VerfasserIn |
Joern Kummerow, Wasja Bloch, Pablo Salazar, Peter Wigger, Serge A. Shapiro |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250131647
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| Publikation (Nr.) |
 EGU/EGU2016-12076.pdf |
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| Zusammenfassung |
| The Mejillones Peninsula constitutes a widely accepted seismic barrier which separates two
major segments of the Andean subduction zone. There is no evidence that past earthquake
ruptures have traversed the barrier.
We recently deployed a dense seismic monitoring system on Mejillones to study the local
structure and seismicity distribution in greater detail. Between June 2013 and October 2015
we detected about 3000 micro seismic events with magnitudes down to Ml = 0.5 and
determined P- and S- arrival times. Precise event location was performed using a regionally
updated velocity model and waveform similarity- based improved arrival time picks.
This provides a detailed seismicity image of the Mejillones region. Despite clear
evidence for young active faults on Mejillones, upper crustal seismicity is only
minor. Earthquakes along the interface occur continuously from 25 to 40km depth.
Activity is also observed within the oceanic crust and is particularly high on the
near-vertical rupture fault of a Mw6.8 intra-slab earthquake which followed only
weeks after the 2007 Mw7.7 Tocopilla earthquake. Slab-related seismicity partly
correlates with the coastline and is higher offshore. We also observe a North-South
segmentation with a high level of seismicity at the northern and southern borders of the
Mejillones Peninsula and less seismicity in its central part, both onshore and offshore. |
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