TY - JOUR A1 - Koulakov, Ivan A1 - Sobolev, Stephan Vladimir A1 - Weber, Bernd A1 - Oreshin, Sergey A1 - Wylegalla, Kurt A1 - Hofstetter, Rami T1 - Teleseismic tomography reveals no signature of the Dead Sea Transform in the upper mantle structure JF - Earth and planetary science letters N2 - We present results of a tomographic inversion of teleseismic data recorded at 48 stations of a temporary network which was installed in the area of the Dead Sea Transform (DST) and operated for 1 yr in the framework of the multidisciplinary DESERT Project. The 3366 teleseismic P and PKP phases from 135 events were hand picked and corrected for surface topography and crustal thickness. The inversion shows pronounced low-velocity anomalies in the crust, beneath the DST, which are consistent with recent results from local-source tomography. These anomalies are likely related to the young sediments and fractured rocks in the fault zone. The deeper the retrieved anomalies are quite weak. Most prominent is the high-velocity strip-like anomaly striking SE-NW. We attribute this anomaly to the inherited heterogeneity of lithospheric structure, with a possible contribution by the shallow Precambrian basement east of the DST and to lower crustal heterogeneity reported in this region by other seismic studies. We do not observe reliable signature of the DST in the upper mantle structure. Some weak indications of low-velocity anomalies in the upper mantle beneath the DST may well result from the down-smearing of the strong upper crustal anomalies. We also see very little topography of the lithosphere-asthenosphere boundary beneath the DST, which would generate significant horizontal velocity variations. These results are consistent with predictions from a recent thereto-mechanical model of the DST. Our tomographic model provides some indication of hot mantle flow from the deeper upper mantle rooted in the region of the Red Sea. However, resolution tests show that this anomaly may well be beyond resolution of the model. (c) 2006 Elsevier B.V. All rights reserved. KW - teleseismic tomography KW - Dead Sea Transform KW - lithosphere KW - asthenosphere KW - tectonophysics Y1 - 2006 U6 - https://doi.org/10.1016/j.epsl.2006.09.039 SN - 0012-821X VL - 252 IS - 1-2 SP - 189 EP - 200 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mechie, James A1 - Ben-Avraham, Zvi A1 - Weber, Michael H. A1 - Götze, Hans-Jürgen A1 - Koulakov, Ivan A1 - Mohsen, A. A1 - Stiller, M. T1 - The distribution of Moho depths beneath the Arabian plate and margins JF - TECTONOPHYSICS N2 - In this study three new maps of Moho depths beneath the Arabian plate and margins are presented. The first map is based on the combined gravity model, EIGEN 06C, which includes data from satellite missions and ground-based studies, and thus covers the whole region between 31 degrees E and 60 inverted perpendicular E and between 12 degrees N and 36 degrees N. The second map is based on seismological and ground-based gravity data while the third map is based only on seismological data. Both these maps show gaps due to lack of data coverage especially in the interior of the Arabian plate. Beneath the interior of the Arabian plate the Moho lies between 32 and 45 km depth below sea level. There is a tendency for higher Pn and Sn velocities beneath the northeastern parts of the plate interior with respect to the southwestern parts of the plate interior. Across the northern, destructive margin with the Eurasian plate, the Moho depths increase to over 50 km beneath the Zagros mountains. Across the conservative western margin, the Dead Sea Transform (DST). Moho depths decrease from almost 40 km beneath the highlands east of the DST to about 21-23 km under the southeastern Mediterranean Sea. This decrease seems to be modulated by a slight depression in the Moho beneath the southern DST. The constructive southwestern and southeastern margins of the Arabian plate also show the Moho shallowing from the plate interior towards the plate boundaries. A comparison of the abruptness of the Moho shallowing between the margins of the Arabian plate, the conjugate African margin at 26 degrees N and several Atlantic margins shows a complex picture and suggests that the abruptness of the Moho shallowing may reflect fundamental differences in the original structure of the margins. (C) 2012 Elsevier B.V. All rights reserved. KW - Moho depths KW - Arabian plate KW - Red Sea KW - Velocity models KW - Receiver functions KW - Satellite gravity data Y1 - 2013 U6 - https://doi.org/10.1016/j.tecto.2012.11.015 SN - 0040-1951 SN - 1879-3266 VL - 609 SP - 234 EP - 249 PB - ELSEVIER SCIENCE BV CY - AMSTERDAM ER - TY - JOUR A1 - Weber, Michael H. A1 - Abu-Ayyash, Khalil A1 - Abueladas, Abdel-Rahman A1 - Agnon, Amotz A1 - Alasonati-Tašárová, Zuzana A1 - Al-Zubi, Hashim A1 - Babeyko, Andrey A1 - Bartov, Yuval A1 - Bauer, Klaus A1 - Becken, Michael A1 - Bedrosian, Paul A. A1 - Ben-Avraham, Zvi A1 - Bock, Günter A1 - Bohnhoff, Marco A1 - Bribach, Jens A1 - Dulski, Peter A1 - Ebbing, Joerg A1 - El-Kelani, Radwan J. A1 - Foerster, Andrea A1 - Förster, Hans-Jürgen A1 - Frieslander, Uri A1 - Garfunkel, Zvi A1 - Götze, Hans-Jürgen A1 - Haak, Volker A1 - Haberland, Christian A1 - Hassouneh, Mohammed A1 - Helwig, Stefan L. A1 - Hofstetter, Alfons A1 - Hoffmann-Rothe, Arne A1 - Jaeckel, Karl-Heinz A1 - Janssen, Christoph A1 - Jaser, Darweesh A1 - Kesten, Dagmar A1 - Khatib, Mohammed Ghiath A1 - Kind, Rainer A1 - Koch, Olaf A1 - Koulakov, Ivan A1 - Laske, Maria Gabi A1 - Maercklin, Nils T1 - Anatomy of the Dead Sea transform from lithospheric to microscopic scale N2 - Fault zones are the locations where motion of tectonic plates, often associated with earthquakes, is accommodated. Despite a rapid increase in the understanding of faults in the last decades, our knowledge of their geometry, petrophysical properties, and controlling processes remains incomplete. The central questions addressed here in our study of the Dead Sea Transform (DST) in the Middle East are as follows: (1) What are the structure and kinematics of a large fault zone? (2) What controls its structure and kinematics? (3) How does the DST compare to other plate boundary fault zones? The DST has accommodated a total of 105 km of left-lateral transform motion between the African and Arabian plates since early Miocene (similar to 20 Ma). The DST segment between the Dead Sea and the Red Sea, called the Arava/Araba Fault (AF), is studied here using a multidisciplinary and multiscale approach from the mu m to the plate tectonic scale. We observe that under the DST a narrow, subvertical zone cuts through crust and lithosphere. First, from west to east the crustal thickness increases smoothly from 26 to 39 km, and a subhorizontal lower crustal reflector is detected east of the AF. Second, several faults exist in the upper crust in a 40 km wide zone centered on the AF, but none have kilometer-size zones of decreased seismic velocities or zones of high electrical conductivities in the upper crust expected for large damage zones. Third, the AF is the main branch of the DST system, even though it has accommodated only a part (up to 60 km) of the overall 105 km of sinistral plate motion. Fourth, the AF acts as a barrier to fluids to a depth of 4 km, and the lithology changes abruptly across it. Fifth, in the top few hundred meters of the AF a locally transpressional regime is observed in a 100-300 m wide zone of deformed and displaced material, bordered by subparallel faults forming a positive flower structure. Other segments of the AF have a transtensional character with small pull-aparts along them. The damage zones of the individual faults are only 5-20 m wide at this depth range. Sixth, two areas on the AF show mesoscale to microscale faulting and veining in limestone sequences with faulting depths between 2 and 5 km. Seventh, fluids in the AF are carried downward into the fault zone. Only a minor fraction of fluids is derived from ascending hydrothermal fluids. However, we found that on the kilometer scale the AF does not act as an important fluid conduit. Most of these findings are corroborated using thermomechanical modeling where shear deformation in the upper crust is localized in one or two major faults; at larger depth, shear deformation occurs in a 20-40 km wide zone with a mechanically weak decoupling zone extending subvertically through the entire lithosphere. Y1 - 2009 UR - http://www.agu.org/journals/rg/ U6 - https://doi.org/10.1029/2008rg000264 SN - 8755-1209 ER -