The Tectonic Geomorphology and the Archeoseismicity of the Dead Sea Transform in Jordan Valley (original) (raw)
Related papers
Active tectonics along the Wadi Araba-Jordan Valley transform fault
Journal of Geophysical Research, 1999
A geological study has been carried out along the 200 km long Wadi Araba following the transform fault that separates the Arabian and Sinai-African Plates. Recent movements along this structure affect upper Pleistocene-Holocene deposits and archaeological sites. Kinematic indicators show sinistral strike-slip and oblique movements, in agreement with the relative motion between the two plates. Other evidence of recent horizontal displacement exists along the Jordan Valley Fault, both on the Dead Sea-Lake Tiberias segment and on the segment north of Lake Tiberias. A minimum horizontal slip rate of 1 cm yr-• has been estimated for both the southern segment of the Wadi Araba Fault and for the southern Jordan River Fault. The two faults can be roughly subdivided into at least four segments: two in the Wadi Araba (80 km long each), one from the Dead Sea to Lake Tiberias (130 km), and one from Lake Tiberias to the Hula graben (>30 km). Faulting may also occur along shorter subsegments, as shown by bends in the Wadi Araba-Jordan River Fault and by the growth of local compression and extension features. Instrument-recorded seismicity appears to be mainly concentrated along some of these subsegments. A comparison between the observed seismic and field-determined slip rates across the fault indicates possible strain accumulation during the last 2000 years.
Historical seismicity of the Jordan Dead Sea Transform region and seismotectonic implications
Arabian Journal of Geosciences, 2014
Based on all available files, catalogs, and previous compilations, it is found that 96 historical earthquakes (M≥6.0) were felt along the Jordan Dead Sea Transform region during the last 2,000 years. More than 50 % of these occurred in the form of sequences and swarms that lasted for different periods, some of which were volcanic related. The largest assigned magnitude is 7.6 with 667 years recurrence period, while the maximum possible future magnitude is 7.8±0.2 with 1,000± 80 years recurrence period. Quiescent periods, with a duration of up to 200 and 400 years and characterized by reduced levels of seismicity, are punctuated by active periods of tens of years when a few large earthquakes occurred. The historical seismicity indicates that all tectonic elements of the study region are presently active. Our results indicate that previous studies overestimate the level of seismicity in this region. Not less than 25 earthquakes, most of which had M≥7.0, are erroneously related to the transform. It is probable that most of these are located within the East Mediterranean region and/or along intraplate faults, rather than the Jordan Dead Sea Transform. This is evidenced by (i) frequency-magnitude results, (ii) moderatelarge East Mediterranean tsunamis, (iii) an apparent higher seismicity of the northernmost three segments compared with the southern three, (iv) relatively high annual seismic slip rate as calculated from the compiled historical seismicity, and (v) overdependence of some previous compilations on secondary rather than primary sources. The revised historical seismicity implies an annual seismic slip rate of about 0.68 cm/year, which indicates that not less than 30 % of the tectonic movements along the regional structures of the study region are aseismic. This is in agreement with results obtained from prehistoric and instrumental data.
Tectonics, 2012
1] The Dead Sea strike-slip fault accommodates the northward motion of Arabia relative to Sinai at a rate of 5mm/yr.Thesouthernsegmentofthefault,theWadiArabafault,runsalongavalleyblanketedinQuaternarysediments.Wefirstfocusedonunderstandingtherelativeandabsolutetimingofemplacementofthealluvialsurfaces.WethendeterminedtheprobablesourceofthesedimentsbeforeassessingtheirlateraloffsettoconstrainthelatePleistocenefaultsliprate.Sevensuccessivemorphostratigraphiclevelswereidentified.Attwosites,werecognizedanalluvialsequenceoffivetosevensuccessivelevelswithagesgettingyoungernorthward,apatternconsistentwiththewesternblockmovingsouthwardrelativetotwofixedfeedingchannelslocatedtotheeast.Surfacesampleswerecollectedfor10Becosmogenicradionuclidedating.FansF3andF5werefoundtobesynchronousfromsitetosite,at102AE26kaand324AE22ka,respectively,whileF4couldbedatedat163AE19kaatonesiteonly.Theseareminimumages,assumingnoerosionofthealluvialsurfaces.Atleasttwooftheseperiodsarecorrelatedwithwetperiodsthatareregionallywelldocumented.Furtheranalysesoftectonicoffsetsareaffectedinmostcasesbylargeuncertaintiesduetotheconfigurationofthesites.Theyindicatemaximumoffsetsof5 mm/yr. The southern segment of the fault, the Wadi Araba fault, runs along a valley blanketed in Quaternary sediments. We first focused on understanding the relative and absolute timing of emplacement of the alluvial surfaces. We then determined the probable source of the sediments before assessing their lateral offset to constrain the late Pleistocene fault slip rate. Seven successive morphostratigraphic levels were identified. At two sites, we recognized an alluvial sequence of five to seven successive levels with ages getting younger northward, a pattern consistent with the western block moving southward relative to two fixed feeding channels located to the east. Surface samples were collected for 10 Be cosmogenic radionuclide dating. Fans F3 and F5 were found to be synchronous from site to site, at 102 AE 26 ka and 324 AE 22 ka, respectively, while F4 could be dated at 163 AE 19 ka at one site only. These are minimum ages, assuming no erosion of the alluvial surfaces. At least two of these periods are correlated with wet periods that are regionally well documented. Further analyses of tectonic offsets are affected in most cases by large uncertainties due to the configuration of the sites. They indicate maximum offsets of 5mm/yr.Thesouthernsegmentofthefault,theWadiArabafault,runsalongavalleyblanketedinQuaternarysediments.Wefirstfocusedonunderstandingtherelativeandabsolutetimingofemplacementofthealluvialsurfaces.WethendeterminedtheprobablesourceofthesedimentsbeforeassessingtheirlateraloffsettoconstrainthelatePleistocenefaultsliprate.Sevensuccessivemorphostratigraphiclevelswereidentified.Attwosites,werecognizedanalluvialsequenceoffivetosevensuccessivelevelswithagesgettingyoungernorthward,apatternconsistentwiththewesternblockmovingsouthwardrelativetotwofixedfeedingchannelslocatedtotheeast.Surfacesampleswerecollectedfor10Becosmogenicradionuclidedating.FansF3andF5werefoundtobesynchronousfromsitetosite,at102AE26kaand324AE22ka,respectively,whileF4couldbedatedat163AE19kaatonesiteonly.Theseareminimumages,assumingnoerosionofthealluvialsurfaces.Atleasttwooftheseperiodsarecorrelatedwithwetperiodsthatareregionallywelldocumented.Furtheranalysesoftectonicoffsetsareaffectedinmostcasesbylargeuncertaintiesduetotheconfigurationofthesites.Theyindicatemaximumoffsetsof5.5 km for the oldest, possibly $1 Ma old, surfaces. They lead to bracketing of the fault slip rate between 5 and 12 mm/yr, with preferred values of 5-7 mm/yr, for the last 300 ka. Citation: Le Béon, M., Y. Klinger, A.-S. Mériaux, M. Al-Qaryouti, R. C. Finkel, O. Mayyas, and P. Tapponnier (2012), Quaternary morphotectonic mapping of the Wadi Araba and implications for the tectonic activity of the southern Dead Sea fault, Tectonics, 31, TC5003,
Tectonic evolution in the Wadi Araba Segment of the Dead Sea Rift, South-West Jordan
Stephan Mueller Special Publication Series, 2001
This work presents the first palaeostress results obtained from fault-slip data along the eastern margins of the Dead Sea Rift (also named Dead Sea Transform) in South-western Jordan. Stress inversion of the fault-slip data was performed using an improved Right-Dieder method, followed by rotational optimisation. Fault-slip data (totalling 2773) include fault planes, striations and sense of movements, obtained from outcrops ranging in age from Neoproterozoic crystalline basement to Holocene sediments. The data were inverted to determine 88 different palaeostress tensors. Eight palaeostress tensor groups (stages) have been identified, ranging from the Late Neoproterozoic to the Holocene period, and have been correlated with the tectonic evolution of the Dead Sea Rift.
Slip rate on the Dead Sea transform fault in northern Araba valley (Jordan
Geophysical Journal International, 2000
The Araba valley lies between the southern tip of the Dead Sea and the Gulf of Aqaba. This depression, blanketed with alluvial and lacustrine deposits, is cut along its entire length by the Dead Sea fault. In many places the fault is well defined by scarps, and evidence for left-lateral strike-slip faulting is abundant. The slip rate on the fault can be constrained from dated geomorphic features displaced by the fault. A large fan at the mouth of Wadi Dahal has been displaced by about 500m since the bulk of the fanglomerates were deposited 77-140kyr ago, as dated from cosmogenic isotope analysis (10Be in chert) of pebbles collected on the fan surface and from the age of transgressive lacustrine sediments capping the fan. Holocene alluvial surfaces are also clearly offset. By correlation with similar surfaces along the Dead Sea lake margin, we propose a chronology for their emplacement. Taken together, our observations suggest an average slip rate over the Late Pleistocene of between 2 and 6mmyr-1, with a preferred value of 4mmyr-1. This slip rate is shown to be consistent with other constraints on the kinematics of the Arabian plate, assuming a rotation rate of about 0.396°Myr-1 around a pole at 31.1°N, 26.7°E relative to Africa.
Stephan Mueller Special Publication Series, 2001
Detailed stratigraphic and structural study of the southeast Dead Sea basin along the Dead Sea Transform in Jordan was carried out in order to determine the deformation history and processes of pullapart basin formation. Fieldwork focused on mapping and collecting structural orientation data in the area of the intersection of the NE-trending, strike-slip Wadi Araba fault (WAF) and the NW-trending, dip-slip Khunayzira fault. The recent movement on the WAF shows spectacular polished fault planes, slickensides, and Riedel and conjugate Riedel shears. During the Late Quaternary the position of the WAF shifted west toward the basin. This is evident from a series of pressure ridges and exposed positive flower structures that do not deform the lacustrine deposits of the Lisan formation (63-15 ka). The Khunayzira fault makes a prominent, curvilinear 50 m-high scarp that trends SE-NW. In the study area, the scarp is highly eroded and sinuous. Slip on the Khunayzira fault branches onto four fault traces near the junction with the WAF. No cross-cutting relationship is observed between the Khunayzira and WAF. These data contradict the idea that strike-slip motion on the WAF terminates and is transferred to dip slip along the Khunayzira fault. Our data agree with the more complex model of the Dead Sea pull-apart basin, that explain the activity of the transverse faults as younger than the formation of the basin. Paleostress calculations based on fault-slip data of the WAF and the faults of the Upper Cretaceous rock show two stress fields. The first is characterized by WNW compression and NNE tension, which represent the Syrian Arc stress field. The second is characterized by NNW compression and ENE tension, which represents the Dead Sea stress field. Study Area Tertiary Eocene-Paleocene limestone Oligocene-Pliocene? oolitic limestone, nonmarine conglomerate Quaternary Alluvium, lacustrine, aeolian, mudflat (sabkha) deposits Cretaceous Lower Cretaceous sandstone Upper Cretaceous limestone, marl, chert, shale, phosphorite Paleozoic Cambrian-Silurian limestone, dolomite, shale, and sandstone Late Precambrian Granite, monzogranite granodiorite, quartz diorite; minor metamorphic roof pendants KEY Dahal Mtn.
Marine and Petroleum Geology, 2006
Interpretation of recently released seismic reflection lines from the Shuna (Eastern Jericho) Basin combined with re-analysis of the lithologic logs of the deep JV-1 and JV-2 boreholes provide new insights into the structure of the sedimentary basin that formed along the Dead Sea Transform fault north of the Dead Sea in Jordan. We identified four major seismic boundaries in the reflection profiles. The upper two were correlated with borehole stratigraphy. These reflection boundaries include the top of the pan-African basement (R4), the base of the Mesozoic (R3), the base of the Cretaceous (R2), and the base of the post-Eocene section (R1). The latter records sedimentation during the Dead Sea Transform tectonic regime. The total thickness attained by the older sedimentary units (Late Cretaceous through Cambrian) is apparently less than 2 km. We identified a subsurface structure, a faulted monocline, with a N-S trend, sub-parallel to the strike of the Dead Sea Transform, that is named here Al Kharrar monocline. The Al Kharrar structural ensemble is buried by syntectonic lacustrine and fluviatile sediments of the Jordan Valley Group. The structure formed as part of the Dead Sea Transform deformation overprinting the Late Cretaceous Syrian arc folds. Continued tectonic deformation is evident from the prominent unconformity at the base of post-Eocene syntectonic deposits that dip NW, W and S away from the structural high. Along the NW-flank of the Al Kharrar monocline syntectonic sediment thickness is generally less than 0.5 km while along the SW-flank it thickens rapidly to nearly 1 km at the southern end of the interpreted seismic lines. This rapid southern subsidence probably continues into the north end of the Dead Sea Basin the lake's shoreline being located less than 3 km to the south. Young bifurcating faults with reverse slip components cutting the eastern part of the Al-Kharrar monocline are attributed to a positive flower structure. This pattern suggests strike slip with localized active compression northeast of the Dead Sea. It may result from local transpression between fault strands that appear to be a northward continuation of the eastern boundary fault of the Dead Sea Basin.