FN Archimer Export Format PT J TI 3-D crustal density model of the Sea of Marmara BT AF Gholamrezaie, Ershad Scheck-Wenderoth, Magdalena Bott, Judith Heidbach, Oliver Strecker, Manfred R. AS 1:1,2;2:1,3;3:1;4:1;5:2; FF 1:;2:;3:;4:;5:; C1 GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany Faculty of Georesources and Materials Engineering, RWTH Aachen, Aachen, Germany C2 GFZ, GERMANY UNIV POSTDAM, GERMANY UNIV RWTH AACHEN, GERMANY IF 2.921 TC 4 UR https://archimer.ifremer.fr/doc/00502/61386/65056.pdf https://archimer.ifremer.fr/doc/00502/61386/65057.pdf https://archimer.ifremer.fr/doc/00502/61386/65058.pdf LA English DT Article CR MARSITECRUISE SEISMARMARA BO Pourquoi pas ? Le Nadir AB The Sea of Marmara, in northwestern Turkey, is a transition zone where the dextral North Anatolian Fault zone (NAFZ) propagates westward from the Anatolian Plate to the Aegean Sea Plate. The area is of interest in the context of seismic hazard of Istanbul, a metropolitan area with about 15 million inhabitants. Geophysical observations indicate that the crust is heterogeneous beneath the Marmara basin, but a detailed characterization of the crustal heterogeneities is still missing. To assess if and how crustal heterogeneities are related to the NAFZ segmentation below the Sea of Marmara, we develop new crustal-scale 3-D density models which integrate geological and seismological data and that are additionally constrained by 3-D gravity modeling. For the latter, we use two different gravity datasets including global satellite data and local marine gravity observation. Considering the two different datasets and the general non-uniqueness in potential field modeling, we suggest three possible “end-member” solutions that are all consistent with the observed gravity field and illustrate the spectrum of possible solutions. These models indicate that the observed gravitational anomalies originate from significant density heterogeneities within the crust. Two layers of sediments, one syn-kinematic and one pre-kinematic with respect to the Sea of Marmara formation are underlain by a heterogeneous crystalline crust. A felsic upper crystalline crust (average density of 2720 kg m−3) and an intermediate to mafic lower crystalline crust (average density of 2890 kg m−3) appear to be cross-cut by two large, dome-shaped mafic high-density bodies (density of 2890 to 3150 kg m−3) of considerable thickness above a rather uniform lithospheric mantle (3300 kg m−3). The spatial correlation between two major bends of the main Marmara fault and the location of the high-density bodies suggests that the distribution of lithological heterogeneities within the crust controls the rheological behavior along the NAFZ and, consequently, maybe influences fault segmentation and thus the seismic hazard assessment in the region. PY 2019 PD JUL SO Solid Earth SN 1869-9510 PU Copernicus GmbH VL 10 IS 3 UT 000471599500001 BP 785 EP 807 DI 10.5194/se-10-785-2019 ID 61386 ER EF