TY - JOUR A1 - Maercklin, Nils A1 - Haberland, Christian A1 - Ryberg, Trond A1 - Weber, Michael H. A1 - Bartov, Yosef T1 - Imaging the Dead Sea Transform with scattered seismic waves N2 - With controlled seismic sources and specifically designed receiver arrays, we image a subvertical boundary between two lithological blocks at the Arava Fault (AF) in the Middle East. The AF is the main strike-slip fault of the Dead Sea Transform (DST) in the segment between the Dead Sea and the Red Sea. Our imaging (migration) method is based on array beamforming and coherence analysis of P to P scattered seismic phases. We use a 1-D background velocity model and the direct P arrival as a reference phase. Careful resolution testing is necessary, because the target volume is irregularly sampled by rays. A spread function describing energy dispersion at localized point scatterers and synthetic calculations for large planar structures provides estimates of the resolution of the images. We resolve a 7 km long steeply dipping reflector offset roughly 1 km from the surface trace of the AF. The reflector can be imaged from about 1 km down to 4 km depth. Previous and ongoing studies in this region have shown a strong contrast across the fault: low seismic velocities and electrical resistivities to the west and high velocities and resistivities to the east of it. We therefore suggest that the imaged reflector marks the contrast between young sedimentary fill in the west and Precambrian rocks in the east. If correct, the boundary between the two blocks is offset about 1 km east of the current surface trace of the AF Y1 - 2004 SN - 0956-540X ER - TY - JOUR A1 - Weber, Michael H. A1 - Abu-Ayyash, Khalil A1 - Abueladas, Abdel-Rahman A1 - Agnon, Amotz A1 - Al-Amoush, H. A1 - Babeyko, Andrey A1 - Bartov, Yosef A1 - Baumann, M. A1 - Ben-Avraham, Zvi A1 - Bock, Günter A1 - Bribach, Jens A1 - El-Kelani, R. A1 - Forster, A. A1 - Förster, Hans-Jürgen A1 - Frieslander, U. A1 - Garfunkel, Zvi A1 - Grunewald, Steffen A1 - Gotze, Hans-Jürgen A1 - Haak, Volker A1 - Haberland, Christian A1 - Hassouneh, Mohammed A1 - Helwig, S. A1 - Hofstetter, Alfons A1 - Jackel, K. H. A1 - Kesten, Dagmar A1 - Kind, Rainer A1 - Maercklin, Nils A1 - Mechie, James A1 - Mohsen, Amjad A1 - Neubauer, F. M. A1 - Oberhänsli, Roland A1 - Qabbani, I. A1 - Ritter, O. A1 - Rumpker, G. A1 - Rybakov, M. A1 - Ryberg, Trond A1 - Scherbaum, Frank A1 - Schmidt, J. A1 - Schulze, A. A1 - Sobolev, Stephan Vladimir A1 - Stiller, M. A1 - Th, T1 - The crustal structure of the Dead Sea Transform N2 - To address one of the central questions of plate tectonics-How do large transform systems work and what are their typical features?-seismic investigations across the Dead Sea Transform (DST), the boundary between the African and Arabian plates in the Middle East, were conducted for the first time. A major component of these investigations was a combined reflection/ refraction survey across the territories of Palestine, Israel and Jordan. The main results of this study are: (1) The seismic basement is offset by 3-5 km under the DST, (2) The DST cuts through the entire crust, broadening in the lower crust, (3) Strong lower crustal reflectors are imaged only on one side of the DST, (4) The seismic velocity sections show a steady increase in the depth of the crust-mantle transition (Moho) from 26 km at the Mediterranean to 39 km under the Jordan highlands, with only a small but visible, asymmetric topography of the Moho under the DST. These observations can be linked to the left-lateral movement of 105 km of the two plates in the last 17 Myr, accompanied by strong deformation within a narrow zone cutting through the entire crust. Comparing the DST and the San Andreas Fault (SAF) system, a strong asymmetry in subhorizontal lower crustal reflectors and a deep reaching deformation zone both occur around the DST and the SAF. The fact that such lower crustal reflectors and deep deformation zones are observed in such different transform systems suggests that these structures are possibly fundamental features of large transform plate boundaries Y1 - 2004 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 - TY - JOUR A1 - Maercklin, Nils A1 - Bedrosian, Paul A. A1 - Haberland, Christian A1 - Ritter, O. A1 - Ryberg, Trond A1 - Weber, Michael H. A1 - Weckmann, Ute T1 - Characterizing a large shear-zone with seismic and magnetotelluric methods : the case of the Dead Sea Transform N2 - Seismic tomography, imaging of seismic scatterers, and magnetotelluric soundings reveal a sharp lithologic contrast along a similar to 10 km long segment of the Arava Fault (AF), a prominent fault of the southern Dead Sea Transform (DST) in the Middle East. Low seismic velocities and resistivities occur on its western side and higher values east of it, and the boundary between the two units coincides partly with a seismic scattering image. At 1 - 4 km depth the boundary is offset to the east of the AF surface trace, suggesting that at least two fault strands exist, and that slip occurred on multiple strands throughout the margin's history. A westward fault jump, possibly associated with straightening of a fault bend, explains both our observations and the narrow fault zone observed by others Y1 - 2005 SN - 0094-8276 ER -