Holocene tectonic deformation along the western margins of the Dead Sea (original) (raw)
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Holocene seismic and tectonic activity in the Dead Sea area
Tectonophysics, 1981
. Holocene seismic and tectonic activity in the Dead Sea area. In: R. Freund and Z. Garfunkel (Editors), The Dead Sea Rift. Tectonophysics, 80: 235-254. The Dead Sea is a large, active graben within the Dead Sea rift, which is bounded by two major strike-slip faults, the Jericho and the Arava faults. We investigated the young tectonic activity along the Jericho fault by excavating trenches, up to 3.5 m deep, across its trace. The trenches penetrate through Late Pleistocene and Holocene sediments. We found that a zone, up to 15 m wide, of disturbed sediments exists along the fault. These disturbed sediments provide evidence for two periods of intensive activity or more likely, for two major earthquakes, that occurred during the last 2000 years. The earthquakes are evident in small faults, vertical throw of a few layers, cracks, unconformities and wide fissures. We further documented evidence for recent sinistral shear along the Jericho fault in deformed sediments and damage to an 8th Century palace on a subsidiary fault. We suggest that the two earthquakes may be correlated with the 31 B.C. earthquake and the 748 A.D. earthquake, reported by the ancients. * Present address: Woodward-Clyde Consultants, Three Embarcadero Center, San Fransisco, Calif. 94111 (U.S.A.).
The Tectonic Geomorphology and the Archeoseismicity of the Dead Sea Transform in Jordan Valley
2007
The continuous record of large surface-rupturing earthquakes along the Dead Sea fault brings unprecedented insights for paleoseismic and archaeoseismic research. In most recent studies, paleoseismic trenching documents the late Holocene faulting activity, while tectonic geomorphology addresses the long-term behavior (> 10 ka), with a tendency to smooth the effect of individual earthquake rupture events (M w > 7). Here, we combine historical, archaeological, and paleoseismic investigations to build a consolidated catalog of destructive surface-rupturing earthquakes for the last 14 ka along the left-lateral Jordan Valley fault segment. The 120km-long fault segment limited to the north and the south by major pull-apart basins (the Hula and the Dead Sea, respectively) is mapped in detail and shows five subsegments with narrow stepovers (width < 3 km). We conducted quantitative geomorphology along the fault, measured more than 20 offset drainages, excavated four trenches at two sites, and investigated archaeological sites with seismic damage in the Jordan Valley. Our results in paleoseismic trenching with 28 radiocarbon datings and the archaeoseismology at Tell Saydiyeh, supplemented with a rich historical seismic record, document 12 surface-rupturing events along the fault segment with a mean interval of ∼1160 yr and an average 5 mm=yr slip rate for the last 25 ka. The most complete part of the catalog indicates recurrence intervals that vary from 280 yr to 1500 yr, with a median value of 790 yr, and suggests an episodic behavior for the Jordan Valley fault. Our study allows a better constraint of the seismic cycle and related short-term variations (late Holocene) versus long-term behavior (Holocene and late Pleistocene) of a major continental transform fault.
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.
Late Pleistocene and Holocene slip rate of the northern Wadi Araba fault, Dead Sea transform, Jordan
Journal of seismology, 2001
The Wadi Araba Valley is a morphotectonic depression along part of the Dead Sea Transform (DST) plate boundary that separates the Arabian plate on the east from the Sinai subplate on the west. The Wadi Araba fault (WAF) is one of the main strike-slip faults between the Gulf of Aqaba and the E-W trending Khunayzira (Amatzayahu) fault that bounds the southern end of the Dead Sea. Just south of the Dead Sea, the WAF cuts across several generations of alluvial fans that formed on tributaries to the Wadi Dahal after the regression of Late Pleistocene Lake Lisan ca. 15 ka. Geomorphic and stratigraphic evidence of active faulting, including left-laterally offset stream channels and alluvial-fan surfaces, yielded fault slip-rate data for the northern segment of WAF. Typical cumulative displacements of 54 m, 39 m, and 22.5 m of stream channels and alluvial-fan surfaces across the fault were measured from detailed geologic and topographic mapping. The 54 m offset of the oldest alluvial-fan surface (Q f 1) occurred after the final lowering of Lake Lisan (16-15 ka) and before 11 ka yielding a slip-rate range of 3.4 mm/yr to 4.9 mm/yr. Based on radiocarbon ages of charcoal and landsnail shell samples from the buried Q f 2 alluvial-fan deposits exposed in trenches excavated across the fault, the 39 m and 22.5 m offsets occurred after 9 ka and 5.8 ka, respectively. These data yield a slip-rate range between 3.9 mm/yr and 6.0 mm/yr. The small variability in these slip-rate estimates for different time periods suggests that the northern Wadi Araba fault has maintained a relatively constant slip rate in the past 15 ka. We calculate an average slip rate of 4.7 ± 1.3 mm/yr since 15 ka based on the three separate displacements and age estimates. Five separate offsets of 3 m were measured from gully bends and the offset of small fault-scarp alluvial fans. These displacement data suggest a coseismic slip of 3 m in the last earthquake, or a cumulative slip of 3 m in the past few earthquakes. A maximum slip of 3 m correspond to a Mw 7 earthquake that ruptures about 49 km of fault length. Using an average slip rate of 4.7 ± 1.3 mm/yr together with a 3-m slipper event suggests a maximum earthquake recurrence interval of this fault segment of 500 to 885 years. Table 1. Geologic estimates of lateral slip rates on the Dead Sea transform fault system Fault segment Evidence Amount of Age of Slip rate Authors offset datum DST offset Miocene 40-45 km 7-12 Ma 3.5-6 mm/yr Freund et al., 1968 fault system rocks 7-10 Ma 4-6 mm/yr Freund et al., 1970 3.1-3.7 Ma 9-15 mm/yr Steinitz et al., 1978 Pliocene-7-10 mm/yr Garfunkel Pleistocene et al., 1981 (4-5 Ma) Last 1,000-1.5-3.5 mm/yr Garfunkel 1,500 years (seismic slip rate) et al., 1981 Yammuneh offset Homs basalts 8 km Miocene-5-10 mm/yr Garfunkel fault Pliocene et al., 1981 offset Litani river 5 km 1-2 Ma 5-10 mm/yr South-Central Methodo offset channels 100-150 m post-Lisan 10 mm/yr Garfunkel Jordan fault et al., 1981 Central Wadi offset alluvial fans 3 km 0.3-0.6 Ma 5-10 mm/yr Garfunkel Araba fault et al., 1981 DST fault offset of E-W 2.1 mm 817 years ∼ 2.5 mm/yr Marco et al., (Hula area) trending walls in the 1997 Crusader Ateret Fortress Southern Wadi offset alluvial fans 150 m 20-23 ka 7.5 mm/yr Zak and Freund, Araba fault 1966 Arava fault offsets in 15 km Late Pliocene 3-7.5 mm/yr Ginat et al., drainage basins and or early 1998 alluvial fans Pleistocene Northern Wadi slumps 6.4 mm/yr El-Isa and Mustafa, Araba fault in Lisan deposits (seismic slip rate) 1986 Northern Wadi offset of the late 500 m 77-140 ka 2-6 mm/yr Klinger et al., Araba fault Pleistocene Dahal preferred rate 2000a alluvial fan of 4 mm/yr Northern Wadi offset gullies and 54 m 16-11 ka 3.4-4.9 mm/yr Niemi et al., Araba fault fan surfaces on 39 m 9-6.5 ka 4.3-6.0 mm/yr this paper tributaries to Wadi 22.5 m 5.8 ka 3.9 mm/yr Dahal avg. 4.7±1.3 mm/yr
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.
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.