A Two-Scale Preparation Phase Preceded an Mw 5.8 Earthquake in the Sea of Marmara Offshore Istanbul, Turkey - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Seismological Research Letters Année : 2020

A Two-Scale Preparation Phase Preceded an Mw 5.8 Earthquake in the Sea of Marmara Offshore Istanbul, Turkey

Stephan Bentz
  • Fonction : Auteur
Grzegorz Kwiatek
  • Fonction : Auteur
Georg Dresen
  • Fonction : Auteur
Christopher Wollin
  • Fonction : Auteur
Oliver Heidbach
  • Fonction : Auteur
Patricia Martínez-Garzòn
  • Fonction : Auteur
Fabrice Cotton
  • Fonction : Auteur
Murat Nurlu
  • Fonction : Auteur
Marco Bohnhoff
  • Fonction : Auteur

Résumé

Abstract We analyze the spatiotemporal evolution of seismicity during a sequence of moderate (an Mw 4.7 foreshock and Mw 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.
Fichier non déposé

Dates et versions

hal-04360082 , version 1 (21-12-2023)

Identifiants

Citer

Virginie Durand, Stephan Bentz, Grzegorz Kwiatek, Georg Dresen, Christopher Wollin, et al.. A Two-Scale Preparation Phase Preceded an Mw 5.8 Earthquake in the Sea of Marmara Offshore Istanbul, Turkey. Seismological Research Letters, 2020, 91 (6), pp.3139-3147. ⟨10.1785/0220200110⟩. ⟨hal-04360082⟩
11 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More