46780
2006
2006
eng
189
200
12
1-2
252
article
Elsevier
Amsterdam
1
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Teleseismic tomography reveals no signature of the Dead Sea Transform in the upper mantle structure
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.
Earth and planetary science letters
10.1016/j.epsl.2006.09.039
0012-821X
wos:2006
WOS:000242860200015
Sobolev, SV (reprint author), GeoForschungszentrum Potsdam, Potsdam, Germany., stephan@gfz-potsdam.de
importub
2020-04-21T15:23:14+00:00
filename=package.tar
eab073210d6b47477363c774843a840f
false
true
Ivan Koulakov
Stephan Vladimir Sobolev
Bernd Weber
Sergey Oreshin
Kurt Wylegalla
Rami Hofstetter
eng
uncontrolled
teleseismic tomography
eng
uncontrolled
Dead Sea Transform
eng
uncontrolled
lithosphere
eng
uncontrolled
asthenosphere
eng
uncontrolled
tectonophysics
Geowissenschaften
Institut für Geowissenschaften
Referiert
Import
34525
2013
2013
eng
234
249
16
609
review
ELSEVIER SCIENCE BV
AMSTERDAM
1
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The distribution of Moho depths beneath the Arabian plate and margins
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.
TECTONOPHYSICS
10.1016/j.tecto.2012.11.015
0040-1951
1879-3266
wos:2011-2013
WOS:000330201000011
Mechie, J (reprint author), Deutsch GeoForschungsZentrum GFZ, Sect Geophys Deep Sounding, D-14473 Potsdam, Germany.
, jimmy@gfz-potsdam.de
James Mechie
Zvi Ben-Avraham
Michael H. Weber
Hans-Jürgen Götze
Ivan Koulakov
A. Mohsen
M. Stiller
eng
uncontrolled
Moho depths
eng
uncontrolled
Arabian plate
eng
uncontrolled
Red Sea
eng
uncontrolled
Velocity models
eng
uncontrolled
Receiver functions
eng
uncontrolled
Satellite gravity data
Institut für Geowissenschaften
Referiert
Institut für Erd- und Umweltwissenschaften
31994
2009
2009
eng
article
1
--
--
--
Anatomy of the Dead Sea transform from lithospheric to microscopic scale
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.
http://www.agu.org/journals/rg/
10.1029/2008rg000264
8755-1209
allegro:1991-2014
10108347
Reviews of geophysics. - ISSN 8755-1209. - 47 (2009), Art. RG2002
Michael H. Weber
Khalil Abu-Ayyash
Abdel-Rahman Abueladas
Amotz Agnon
Zuzana Alasonati-Tašárová
Hashim Al-Zubi
Andrey Babeyko
Yuval Bartov
Klaus Bauer
Michael Becken
Paul A. Bedrosian
Zvi Ben-Avraham
Günter Bock
Marco Bohnhoff
Jens Bribach
Peter Dulski
Joerg Ebbing
Radwan J. El-Kelani
Andrea Foerster
Hans-Jürgen Förster
Uri Frieslander
Zvi Garfunkel
Hans-Jürgen Götze
Volker Haak
Christian Haberland
Mohammed Hassouneh
Stefan L. Helwig
Alfons Hofstetter
Arne Hoffmann-Rothe
Karl-Heinz Jaeckel
Christoph Janssen
Darweesh Jaser
Dagmar Kesten
Mohammed Ghiath Khatib
Rainer Kind
Olaf Koch
Ivan Koulakov
Maria Gabi Laske
Nils Maercklin
Institut für Geowissenschaften
Referiert
Institut für Erd- und Umweltwissenschaften