FN Archimer Export Format PT J TI How far did the surface rupture of the 1999 Izmit earthquake reach in Sea of Marmara? BT AF GASPERINI, Luca POLONIA, Alina BORTOLUZZI, Giovanni HENRY, Pierre LE PICHON, Xavier TRYON, Michael CAGATAY, Namik GELI, Louis AS 1:1;2:1;3:1;4:2;5:2;6:3;7:4;8:5; FF 1:;2:;3:;4:;5:;6:;7:;8:PDG-REM-GM; C1 CNR, ISMAR, I-40129 Bologna, Italy. CEREGE, F-13545 Aix En Provence, France. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. ITU, Fac Min, EMCOL, TR-34469 Istanbul, Turkey. Ifremer, F-29280 Plouzane, France. C2 CNR, ITALY CEREGE, FRANCE UNIV CALIF SAN DIEGO, USA ITU, TURKEY IFREMER, FRANCE SI BREST SE PDG-REM-GM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-europe copubli-int-hors-europe copubli-sud IF 2.867 TC 19 TU CNRS COLLEGE DE FRANCE IFREMER IRD UNIVERSITE AIX-MARSEILLE UR https://archimer.ifremer.fr/doc/00031/14256/12205.pdf LA English DT Article CR MARMARA MARMARASCARPS MARNAUT BO Le SuroƮt L'Atalante AB An open problem concerning the Mw 7.4, 1999 Izmit earthquake along the North Anatolian Fault (NAF) system is the apparent conflict between estimates of strike-slip deformation based on field and remote sensing data. This is due to the fact that the main strand of the NAF west of the epicenter lies below the Sea of Marmara. Seismological evidence and models based on synthetic aperture radar interferometry suggest that coseismic and early postseismic displacement accumulated after the earthquake could have reached the western end of the Izmit Gulf and possibly the southern edge of the Cinarcik Basin, tapering off along the northern coast of the Armutlu Peninsula, more than 60 km from the epicenter. This scenario is not confirmed by onshore field observations that point toward a termination of the surface rupture around 30 km to the east. These discrepancies convey high uncertainties in the estimate of the tectonic load produced by the Izmit earthquake on the adjacent fault segment toward Istanbul. We analyzed data from different sources, including high-resolution marine geophysical surveys and two Nautile dives along the fault-controlled canyon that connects Izmit Cinarcik basins. Our observations suggest that the surface rupture of the 1999 Izmit earthquake propagated through the shallow Gulf but did not reach the deep Marmara basins. In fact, along the slope between Cinarcik and the western end of the Izmit Gulf, we do not observe fault-related ruptures affecting the sea-floor but rather a series of active gas seeps and "black patches" that mark the presence of known active faults. Our findings have implications for seismic risk assessment in the highly populated region of Istanbul, both for the estimate of tectonic load transferred to the next fault segments and the location of the next earthquake. Citation: Gasperini, L., A. Polonia, G. Bortoluzzi, P. Henry, X. Le Pichon, M. Tryon, N. Cagatay, and L. Geli (2011), How far did the surface rupture of the 1999 Izmit earthquake reach in Sea of Marmara?, Tectonics, 30, TC1010, doi: 10.1029/2010TC002726. PY 2011 PD FEB SO Tectonics SN 0278-7407 PU Amer Geophysical Union VL 30 UT 000287818800001 DI 10.1029/2010TC002726 ID 14256 ER EF