TY  - JOUR
A1  - Durand, Virginie
A1  - Bentz, Stephan
A1  - Kwiatek, Grzegorz
A1  - Dresen, Georg
A1  - Wollin, Christopher
A1  - Heidbach, Oliver
A1  - Martinez-Garzon, Patricia
A1  - Cotton, Fabrice
A1  - Nurlu, Murat
A1  - Bohnhoff, Marco
T1  - A two-scale preparation phase preceded an M-w 5.8 earthquake in the sea of marmara offshore Istanbul, Turkey
T2  - Seismological research letters
N2  - We analyze the spatiotemporal evolution of seismicity during a sequence of moderate (an M-w 4.7 foreshock and M-w 5.8 mainshock) earthquakes occurring in September 2019 at the transition between a creeping and a locked segment of the North Anatolian fault in the central Sea of Marmara, northwest Turkey. To investigate in detail the seismicity evolution, we apply a matched-filter technique to continuous waveforms, thus reducing the magnitude threshold for detection. Sequences of foreshocks preceding the two largest events are clearly seen, exhibiting two different behaviors: a long-term activation of the seismicity along the entire fault segment and a short-term concentration around the epicenters of the large events. We suggest a two-scale preparation phase, with aseismic slip preparing the mainshock final rupture a few days before, and a cascade mechanism leading to the nucleation of the mainshock. Thus, our study shows a combination of seismic and aseismic slip during the foreshock sequence changing the strength of the fault, bringing it closer to failure.
Y1  - 2020
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/61488
SN  - 0895-0695
SN  - 1938-2057
VL  - 91
IS  - 6
SP  - 3139
EP  - 3147
CY  - Boulder
ER  -