Seismicity rate increases associated with slow slip episodes prior to the 2012 M-w 7.4 Ometepec earthquake
Por:
Colella, Harmony V., Sit, Stefany M., Brudzinski, Michael R., Graham, Shannon E., DeMets, Charles, Holtkamp, Stephen G., Skoumal, Robert J., Ghouse, Noorulann, Cabral-Cano, Enrique, Kostoglodov, Vladimir, Arciniega-Ceballos, Alejandra
Publicada:
15 abr 2017
Resumen:
The March 20, 2012 M-w 7.4 Ometepec earthquake in the Oaxaca region of
Southern Mexico provides a unique opportunity to examine whether subtle
changes in seismicity, tectonic tremor, or slow slip can be observed
prior to a large earthquake that may illuminate changes in stress or
background slip rate. Continuous Global Positioning System (cGPS) data
reveal a 5-month-long slow slip event (SSE) between similar to 20 and 35
km depth that migrated toward and reached the vicinity of the mainshock
a few weeks prior to the earthquake. Seismicity in Oaxaca is examined
using single station tectonic tremor detection and multi-station
waveform template matching of earthquake families. An increase in
seismic activity, detected with template matching using aftershock
waveforms, is only observed in the weeks prior to the mainshock in the
region between the SSE and mainshock. In contrast, a SSE similar to 15
months earlier occurred at similar to 25-40 km depth and was primarily
associated with an increase in tectonic tremor. Together, these
observations indicate that in the Oaxaca region of Mexico shallower slow
slip promotes elevated seismicity rates, and deeper slow slip promotes
tectonic tremor. Results from this study add to a growing number of
published accounts that indicate slow slip may be a common
pre-earthquake signature. (C) 2017 Elsevier B.V. All rights reserved.
Filiaciones:
Colella, Harmony V.:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ USA
Univ Calif Berkeley, Berkeley, CA 94720 USA
Sit, Stefany M.:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Univ Illinois, Chicago, IL USA
Brudzinski, Michael R.:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Graham, Shannon E.:
Univ Wisconsin Madison, Dept Geosci, Madison, WI USA
Harvard Univ, Cambridge, MA 02138 USA
DeMets, Charles:
Univ Wisconsin Madison, Dept Geosci, Madison, WI USA
Holtkamp, Stephen G.:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Univ Alaska Fairbanks, Fairbanks, AK 99775 USA
Skoumal, Robert J.:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Ghouse, Noorulann:
Miami Univ, Dept Geol & Environm Earth Sci, Oxford, OH 45056 USA
Oklahoma Geol Survey, Norman, OK USA
Cabral-Cano, Enrique:
Univ Wisconsin Madison, Dept Geosci, Madison, WI USA
Kostoglodov, Vladimir:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City, DF, Mexico
Arciniega-Ceballos, Alejandra:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City, DF, Mexico
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