Onset of aseismic creep on major strike-slip faults


Çakir, Ziyadin
Ergintav, Semih
Özener, Haluk
Doǧan, Uǧur
Akoglu, Ahmet
Meghraoui, Mustapha
Reilinger, Robert E.

KAUST Department
Physical Science and Engineering (PSE) Division

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Time series analysis of spaceborne synthetic aperture radar (SAR) data, GPS measurements, and field observations reveal that the central section of the Izmit (Turkey) fault that slipped with a supershear rupture velocity in the A.D. 1999, Mw7.4, Izmit earthquake began creeping aseismically following the earthquake. Rapid initial postseismic afterslip decayed logarithmically with time and appears to have reached a steady rate comparable to the pre-earthquake full fault-crossing rate, suggesting that it may continue for decades and possibly until late in the earthquake cycle. If confirmed by future monitoring, these observations identify postseismic afterslip as a mechanism for initiating creep behavior along strike-slip faults. Long-term afterslip and/or creep has significant implications for earthquake cycle models, recurrence intervals of large earthquakes, and accordingly, seismic hazard estimation along mature strike-slip faults, in particular for Istanbul which is believed to lie adjacent to a seismic gap along the North Anatolian fault in the Sea of Marmara.

Cakir, Z., Ergintav, S., Ozener, H., Dogan, U., Akoglu, A. M., Meghraoui, M., & Reilinger, R. (2012). Onset of aseismic creep on major strike-slip faults. Geology, 40(12), 1115–1118. doi:10.1130/g33522.1

InSAR data were provided by European Space Agency under Project AOTR-2436 and by the Geohazard Supersites program, and were processed at the TUBITAK ULAKBIM High Performance and Grid Computing Centre (Turkey). We thank Onur Tan and Aynur Dikbas for their field assistance, and Aral Okay, Roland Burgmann, and an anonymous reviewer for their helpful reviews. Reilinger's participation was supported by U.S. National Science Foundation grant EAR-1045487 to the Massachusetts Institute of Technology. This study is supported by TUBITAK project 107Y281.

Geological Society of America



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