Gas and seismicity within the Istanbul seismic gap

L. Géli*, P. Henry, C. Grall, J. B. Tary, A. Lomax, E. Batsi, V. Riboulot, E. Cros, C. Gürbüz, S. E. Işlk, A. M.C. Sengör, X. Le Pichon, L. Ruffine, S. Dupré, Y. Thomas, D. Kalafat, G. Bayrakci, Q. Coutellier, T. Regnier, G. WestbrookH. Saritas, G. Çifçi, M. N. Çaǧatay, M. S. Özeren, N. Görür, M. Tryon, M. Bohnhoff, L. Gasperini, F. Klingelhoefer, C. Scalabrin, J. M. Augustin, D. Embriaco, G. Marinaro, F. Frugoni, S. Monna, G. Etiope, P. Favali, A. Bécel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the "Istanbul seismic gap") has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5-5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain.

Original languageEnglish
Article number6819
JournalScientific Reports
Volume8
Issue number1
DOIs
Publication statusPublished - 1 Dec 2018

Bibliographical note

Publisher Copyright:
© 2018 The Author(s).

Funding

This work is based on the results of 15 years of continuous, marine investigations in the Sea of Marmara, conducted within both bi-lateral collaborations (France-Turkey; Italy-Turkey) and EU-funded Research Programmes, e.g. the ESONET Network of Excellence (contract N° 036851) and the MARSITE Integrated Project (contract N° 308417). Jean-François Rolin and Roland Person, coordinators of ESONET, as well as Nurcan Özel and Meral Agualdis, respectively coordinator and project manager of MARSITE are warmly acknowledged. Acknowledgements are also addressed to the Turkish Navy and to the Turkish Hydrographic Service (SHOD) for supporting the operations at sea, particularly our correspondent, Captain Erhan Gezgin; to the personnel of the French Embassy in Ankara, particularly Mrs Bonnafous-Boucher; to CNR and to Ifremer for funding operations at sea of R/V Le Suroit, R/V Pourquoi pas? and R/V Urania, respectively; to the Institute of Marine Science and Technology of the University of Izmir for support with R/V Piri Reis; to Pascal Pelleau, Mikaël Roudaut and Ronan Apprioual for their technical support; to professor Oguz Özel, for his support for using R/V Yunuz of Istanbul University; to the personnel of Ineris -Armand Lizeur, Emmanuel Klein and Pascal Bigarré-for their support in using the SYTMIS software; to Jean Schmittbuhl, Hayrullah Karabulut and Michel Bouchon for fruitful discussions and for providing unpublished manuscript; to Miraille Laigle and Alfred Hirn for providing the deep-seismic data from the Seismarmara Cruise; to COST action FLOWS for support to collaboration between EU and Turkey on transform-type plate boundary studies. Anthony Lomax worked as a MARSITE sub-contractor, under CNRS-Contract N° MA201301A; Estelle Cros worked under a grant from Institut Carnot Ifremer-Edrome, Contract reference number 06/11/2013. Intense use was made of Global Mapping Tools (GMT)57. Data available on http://doi.org/10.17882/49764.

FundersFunder number
Institut Carnot Ifremer-Edrome06/11/2013
Seventh Framework Programme308417
Natural Environment Research Councilnoc010011
Consiglio Nazionale delle RicercheMA201301A

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