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Karabacak V.,Eskiehir Osmangazi University | Altunel E.,Eskiehir Osmangazi University | Meghraoui M.,Institute Of Physique Du Globe | Akyuz H.S.,Technical University of Istanbul
Tectonophysics | Year: 2010

The left-lateral strike-slip Dead Sea Fault Zone (DSFZ) extends from the Red Sea in the south to the East Anatolian Fault Zone (EAFZ) in the north. This study examines the northern part of the DSFZ around Amik Basin and presents surface and subsurface geological evidence for the Quaternary activity and initiation age of the northernmost DSFZ. The DSFZ extends N-S in the south of the Amik Basin where clear geological and morphological evidence exists for faulting. Geological observations around Amik Basin, analyses of borehole data and electrical resistivity profiles within the Amik Basin indicate that the activity of the northern DSFZ started after Pliocene in the Amik Basin. Subsurface data in the basin suggest that the DSFZ offsets a pre-Quaternary basin sinistrally by about 7.9 km. The offset pre-Quaternary basin suggests at least 4.94 ± 0.13 mm/year slip rate for the northern part of the DSFZ. The Karasu Fault Zone (KFZ) extends in an en-echelon pattern along the western margin of the Karasu Valley and it transfers the significant amount of slip from DSFZ to the EAFZ. © 2009 Elsevier B.V. All rights reserved.

De Michele M.,Bureau de Recherches Geologiques et Minieres | Raucoules D.,Bureau de Recherches Geologiques et Minieres | Lasserre C.,Joseph Fourier University | Pathier E.,Joseph Fourier University | And 4 more authors.
Earth, Planets and Space | Year: 2010

L-band spaceborne Synthetic Aperture Radar (SAR) amplitude images are used to map the Sichuan earthquake rupture (China, Aw 7.9, 12 May 2008) and to identify the faults activated by the earthquake. A sub-pixel correlation method is used to retrieve the coseismic displacement field projected into the line of sight of the satellite and the horizontal along-track direction, and to map the surface rupture. The earthquake broke ~270 km of the Beichuan fault and ~70 km of the Guanxian fault, with a complex thrust-dextral slip mechanism. Along the southwestern part of the rupture, slip seems to be partitioned into a dextral-dominant component on the Beichuan fault and a thrust-dominant component on the Guanxian fault. Dextral slip may also be dominant at the northeastern tip of the Beichuan ruptured fault. Coseismic surface displacements reach on average 3 to 4 m in both measured directions. The SAR rupture mapping has proven complementary to field studies extending the zone of co-seismic displacements and identifying other possible co-seismic rupture strands. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS).

Meghraoui M.,Institute Of Physique Du Globe
Journal of Seismology | Year: 2010

New historical data from primary sources, allow us to revisit the Djidjelli earthquakes of 21 and 22 August 1856 (I0 VIII, IX respectively). These two large seismic events are among the most significant events that have affected the North African coast. They have caused extensive damage and generated a tsunami that propagated at several harbours of the western Mediterranean Sea. The effects of each earthquake are analysed from all documentary source materials, emphasising the confrontation of observations and data for an accurate reconstruction of the macroseismic field of both events. The method used provides a more precise way to determine the characteristics of the Djidjelli earthquakes. © 2010 Springer Science+Business Media B.V.

Salomon E.,University of Munster | Salomon E.,Johannes Gutenberg University Mainz | Schmidt S.,University of Munster | Schmidt S.,Institute Of Physique Du Globe | And 3 more authors.
Bulletin of the Seismological Society of America | Year: 2013

In 1861, one of the most destructive earthquakes in the history of Argentina destroyed the city of Mendoza (currently 1 million inhabitants). The magnitudeMS ~7.0 earthquake is inferred to have occurred on the 31-km-long La Cal thrust fault, which extends from Mendoza to the north, where it offsets an alluvial fan and small inset terraces along a well-preserved fault scarp. A trench excavated on a terrace that is vertically offset by ~2.5 m exposes two main stratigraphic units separated by an erosional unconformity. The coarse-grained upper unit is deformed by three eastvergent folds (F1-F3). Retrodeformation of these folds yields total displacements of ~2.0 m,~2.4 m, and~0.5 mon the underlying fault splays, respectively. The displacement of ~2.0 m recorded by fold F1 is interpreted as the result of the fault rupture that caused the 1861 earthquake. F2 and F3 were presumably generated during the penultimate event with an inferred magnitude of Mw ~7.0, although formation during two distinct ruptures cannot be excluded. Finite-element modeling shows that coseismic folding above the tip of a blind thrust fault is a physically plausible mechanism to generate these folds.Apublished luminescence age of 770 ± 76 years, which is interpreted to date the formation of the deformed terrace, indicates that the two (or possibly three) scarp-forming events occurred during the last ~800 years. The fine-grained sediments below the erosional unconformity-that contain evidence for at least one older earthquake- are dated at ~12 kyr. Our results indicate that elastic strain energy, which is accumulating at the front of the Precordillera today as shown by Global Positioning System (GPS) data, was repeatedly released during earthquakes on the La Cal fault in the past. Hence, the La Cal thrust fault poses a serious threat to the city of Mendoza.

Demeter F.,CNRS Eco-anthropology and Ethnobiology | Patole-Edoumba E.,Museum dHistoire Naturelle de La Rochelle | Duringer P.,University of Strasbourg | Bacon A.,French National Center for Scientific Research | And 5 more authors.
Geoarchaeology | Year: 2010

In 1963, E. Saurin and J.-P. Carbonnel discovered the Sre Sbov site on an alluvial terrace of the Mekong River in central Cambodia. Saurin described a lithic typology dating to the Lower/Middle Pleistocene from this site. Although the original lithic assemblage has been lost, this typology has been used continuously as a reference by Southeast Asian prehistorians. In 2007, a Khmer-French team conducted excavations at Sre Sbov that yielded numerous pebbles and cobbles showing apparently convincing handmade removals, as Saurin had previously described. However, an in-depth study of this assemblage, combined with a geological survey of the area, led to the conclusion that the stones were, in fact, of natural origin, and that for this reason their typology should be disregarded. Using satellite imagery and geological surveys, we explain how such a misinterpretation may have occurred and define a "buffer zone," corresponding to the maximal extent of the proto-Mekong River, where fluvially reworked pebbles and cobbles resembling artifacts may be recovered. © 2009 Wiley Periodicals, Inc.

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