43466
2019
2019
eng
785
807
23
737
postprint
1
2019-09-11
2019-09-11
--
3-D crustal density model of the Sea of Marmara
Abstract. 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 kgm⁻³) and an intermediate to mafic lower crystalline crust (average density of 2890 kgm⁻³) appear to be cross-cut by two large, dome-shaped mafic highdensity bodies (density of 2890 to 3150 kgm⁻³) of considerable thickness above a rather uniform lithospheric mantle (3300 kgm⁻³). The spatial correlation between two major bends of the main Marmara fault and the location of the highdensity 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.
Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
10.25932/publishup-43466
urn:nbn:de:kobv:517-opus4-434661
1866-8372
Solid Earth 10 (2019) S. 785–807 DOI: 10.5194/se-10-785-2019
<a href="http://publishup.uni-potsdam.de/opus4-ubp/frontdoor/index/index/docId/43465">Bibliographieeintrag der Originalveröffentlichung/Quelle</a>
CC-BY - Namensnennung 4.0 International
Ershad Gholamrezaie
Magdalena Scheck-Wenderoth
Judith Bott
Oliver Heidbach
Manfred Strecker
Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
737
eng
uncontrolled
North Anatolian Fault
eng
uncontrolled
Shear Zone
eng
uncontrolled
Northwestern Anatolia
eng
uncontrolled
Geomechanical Model
eng
uncontrolled
Tectonic Evolution
eng
uncontrolled
Slip Distribution
eng
uncontrolled
Middle Strand
eng
uncontrolled
Pull-Apart
eng
uncontrolled
Long-Term
eng
uncontrolled
NW Turkey
Geowissenschaften
open_access
Institut für Geowissenschaften
Referiert
Open Access
Universität Potsdam
https://publishup.uni-potsdam.de/files/43466/pmnr737.pdf
43465
2019
2019
eng
785
807
23
10
article
Copernicus Publ.
Göttingen
1
2019-06-13
2019-06-13
--
3-D crustal density model of the Sea of Marmara
Abstract. 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 kgm⁻³) and an intermediate to mafic lower crystalline crust (average density of 2890 kgm⁻³) appear to be cross-cut by two large, dome-shaped mafic highdensity bodies (density of 2890 to 3150 kgm⁻³) of considerable thickness above a rather uniform lithospheric mantle (3300 kgm⁻³). The spatial correlation between two major bends of the main Marmara fault and the location of the highdensity 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.
Solid Earth
10.5194/se-10-785-2019
1869-9510
1869-9529
Universität Potsdam
PA 2019_92
1992.06
<a href="http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434661">Zweitveröffentlichung in der Schriftenreihe Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe ; 737</a>
CC-BY - Namensnennung 4.0 International
Ershad Gholamrezaie
Magdalena Scheck-Wenderoth
Judith Bott
Oliver Heidbach
Manfred Strecker
eng
uncontrolled
North Anatolian Fault
eng
uncontrolled
Shear Zone
eng
uncontrolled
Northwestern Anatolia
eng
uncontrolled
Geomechanical Model
eng
uncontrolled
Tectonic Evolution
eng
uncontrolled
Slip Distribution
eng
uncontrolled
Middle Strand
eng
uncontrolled
Pull-Apart
eng
uncontrolled
Long-Term
eng
uncontrolled
NW Turkey
Geowissenschaften
open_access
Institut für Geowissenschaften
Referiert
Publikationsfonds der Universität Potsdam
Open Access