@article{KoulakovSobolevWeberetal.2006, author = {Koulakov, Ivan and Sobolev, Stephan Vladimir and Weber, Bernd and Oreshin, Sergey and Wylegalla, Kurt and Hofstetter, Rami}, title = {Teleseismic tomography reveals no signature of the Dead Sea Transform in the upper mantle structure}, series = {Earth and planetary science letters}, volume = {252}, journal = {Earth and planetary science letters}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2006.09.039}, pages = {189 -- 200}, year = {2006}, abstract = {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.}, language = {en} } @misc{MechieBenAvrahamWeberetal.2013, author = {Mechie, James and Ben-Avraham, Zvi and Weber, Michael H. and G{\"o}tze, Hans-J{\"u}rgen and Koulakov, Ivan and Mohsen, A. and Stiller, M.}, title = {The distribution of Moho depths beneath the Arabian plate and margins}, series = {TECTONOPHYSICS}, volume = {609}, journal = {TECTONOPHYSICS}, publisher = {ELSEVIER SCIENCE BV}, address = {AMSTERDAM}, issn = {0040-1951}, doi = {10.1016/j.tecto.2012.11.015}, pages = {234 -- 249}, year = {2013}, abstract = {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.}, language = {en} } @article{WeberAbuAyyashAbueladasetal.2009, author = {Weber, Michael H. and Abu-Ayyash, Khalil and Abueladas, Abdel-Rahman and Agnon, Amotz and Alasonati-Taš{\´a}rov{\´a}, Zuzana and Al-Zubi, Hashim and Babeyko, Andrey and Bartov, Yuval and Bauer, Klaus and Becken, Michael and Bedrosian, Paul A. and Ben-Avraham, Zvi and Bock, G{\"u}nter and Bohnhoff, Marco and Bribach, Jens and Dulski, Peter and Ebbing, Joerg and El-Kelani, Radwan J. and Foerster, Andrea and F{\"o}rster, Hans-J{\"u}rgen and Frieslander, Uri and Garfunkel, Zvi and G{\"o}tze, Hans-J{\"u}rgen and Haak, Volker and Haberland, Christian and Hassouneh, Mohammed and Helwig, Stefan L. and Hofstetter, Alfons and Hoffmann-Rothe, Arne and Jaeckel, Karl-Heinz and Janssen, Christoph and Jaser, Darweesh and Kesten, Dagmar and Khatib, Mohammed Ghiath and Kind, Rainer and Koch, Olaf and Koulakov, Ivan and Laske, Maria Gabi and Maercklin, Nils}, title = {Anatomy of the Dead Sea transform from lithospheric to microscopic scale}, issn = {8755-1209}, doi = {10.1029/2008rg000264}, year = {2009}, abstract = {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.}, language = {en} }