No significant steady state surface creep along the North Anatolian Fault offshore Istanbul: Results of 6 months of seafloor acoustic ranging
|Author(s)||Sakic P.1, 2, Piete Helene3, 4, Ballu V.1, 2, Royer J. -Y.3, 4, Kopp H.5, Lange D.5, Petersen F.5, Ozeren M. S.6, Ergintav S.7, 8, Geli Louis9, Henry P.10, 11, Deschamps Anne3, 4|
|Affiliation(s)||1 : Univ La Rochelle, Lab Littoral Environm & Soc, La Rochelle, France.
2 : CNRS, La Rochelle, France.
3 : Univ Brest, Lab Geosci Ocean, Plouzane, France.
4 : CNRS, Plouzane, France.
5 : GEOMAR Helmholtz Zentrum Ozeanforsch, Dynam Ozeanbodens FB4, Kiel, Germany.
6 : Istanbul Tech Univ, Eurasian Inst Earth Sci, Istanbul, Turkey.
7 : Bogazici Univ, Kandilli Observ, Istanbul, Turkey.
8 : Bogazici Univ, Earthquake Res Inst, Dept Geodesy, Istanbul, Turkey.
9 : Inst Carnot EDROME, Lab Aleas Geol & Dynam Sedimentaire, UR Geosci Marines, IFREMER, Plouzane, France.
10 : Aix Marseille Univ, CEREGE, CNRS, IRD, Aix En Provence, France.
11 : Coll France, Aix En Provence, France.
|Source||Geophysical Research Letters (0094-8276) (Amer Geophysical Union), 2016-07 , Vol. 43 , N. 13 , P. 6817-6825|
|WOS© Times Cited||25|
|Keyword(s)||seafloor geodesy, North Anatolian Fault, Marmara Sea, acoustic ranging|
|Abstract||The submarine Istanbul-Silivri fault segment, within 15 km of Istanbul, is the only portion of the North Anatolian Fault that has not ruptured in the last 250 years. We report first results of a seafloor acoustic ranging experiment to quantify current horizontal deformation along this segment and assess whether the segment is creeping aseismically or accumulating stress to be released in a future event. Ten transponders were installed to monitor length variations along 15 baselines. A joint least squares inversion for across-fault baseline changes, accounting for sound speed drift at each transponder, precludes fault displacement rates larger than a few millimeters per year during the 6 month observation period. Forward modeling shows that the data better fit a locked state or a very moderate surface creep—less than 6 mm/yr compared to a far-field slip rate of over 20 mm/yr—suggesting that the fault segment is currently accumulating stress.|