Migration and localization of faulting near the intersection of the Dead Sea Fault and the Carmel−Gilboa−Faria Fault System (original) (raw)
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Journal of Geophysical Research, 2012
Large-scale crustal deformation in the Levant is mainly related to the DST and the CFS. The former is an active left lateral transform, bounding the Arabian plate and the Sinai sub-plate, and the latter branches out of the former and separates the Sinai sub-plate into two tectonic domains. In this study we obtain the velocities of 33 permanent GPS stations and 145 survey stations that were surveyed in three campaigns between 1996 and 2008. We use a simple 1-D elastic dislocation model to infer the slip rate and locking depth along various segments of the DST. We infer a 3.1-4.5 mm/yr slip rate and a 7.8-16.5 km locking depth along the DST north of the CFS, and a slip rate of 4.6-5.9 mm/yr and locking depth of 11.8-24 km along the Jericho Valley, south of the CFS. Further south, along the Arava Valley we obtain a slip rate of 4.7-5.4 mm/yr and a locking depth of 12.1-23 km. We identify an oblique motion along the Carmel Fault with 0.7mm/yrleft−lateraland0.7 mm/yr left-lateral and 0.7mm/yrleft−lateraland0.6 mm/yr extension rates, resulting in N-S extension across the Carmel Fault. This result, together with the decrease in DST slip velocity from the Jericho Valley to the segment north of the CFS, confirms previous suggestions, according to which part of the slip between Arabia and Sinai is being transferred from the DST to the CFS.
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,
Tectonophysics, 2020
The cities of Elat, Israel and neighboring Aqaba, Jordan are major economic, cultural, and seaport centers. They are located on the northern shore of the Gulf of Aqaba/Elat (GAE) directly on the Dead Sea Transform. Yet the precise location of the fault trace and its tectonic activity are lacking. The interpretation of seismic reflection profiles across the GAE beach and paleoseismic trench data located 2.2 km north of the shoreline provide evidence that the active offshore mapped Avrona Fault extends onland along the eastern side of the Elat Sabkha (mudflat), where three prominent fault strands crosscut the sedimentary fill. Mismatch of reflector geometry across the faults and flower structures indicate strike-slip faulting with a normal-slip component. Subsurface data from two trenching sites provide evidence for a minimum of two surface ruptures and two paleoliquefaction events. Faulting is constrained by radiocarbon dating for an Event 1 between 897 and 992 CE and Event 2 after 1294 CE. We suggest that the historically documented 1068 CE, and at least one later earthquake in 1458 or 1588 CE, ruptured the Elat Sabkha site. Based on fault mapping, we suggest a minimum value of M 6.6 for the 1068 CE earthquake. Whereas no surface rupture was observed for the 1212 CE historical earthquake, fluidized strata radiocarbon dated to before 1269-1389 CE identified as paleoliquefaction may be attributed to it. Two liquefaction sand-blows mapped in the trench likely formed after 1337 CE and before 1550 CE, which possibly occurred at the same time as in the second faulting event. Our data suggest that no large event occurred along the Avrona segment in the past ~430-550 years. Given a ~ 5 mm/yr slip rate, we conclude that a significant period of time passed since the last surface rupturing on the Avrona Fault, increasing its seismic potential.
Introduction. The Dead Sea Fault System (DSFS) represents the left-lateral transform boundary between the Arabian and Sinai plates (e.g. Jackson and McKenzie, 1988), stretching from the Red Sea mid-oceanic ridge to the south, to the Bitlis-Zagros (southern Turkey) continental collision zone to the north, where the DSFS joins with the East Anatolian fault (EAF; Fig. 1a). The DSFS is generally subdivided into three sections (Fig. 1b). The southern section, extending from the Gulf of Aqaba (Red Sea) through the Jordan Valley, is characterized by the presence of predominantly leftlateral strike-slip faults striking between N12°E and N20°E, having a small component of extension in the south (Gulf of Aqaba) and increasing compression toward the north (
Geophysical Journal International, 2010
New Global Positioning System (GPS) measurements in NW Syria provide the first direct observations of near-field deformation associated with the northern Dead Sea fault system (DSFS) and demonstrate that the kinematics of the northern section of this transform plate boundary between the Arabian and Sinai plates deviate significantly from plate model predictions. Velocity estimates based on GPS survey campaigns in 2000, 2007 and 2008, demonstrate left-lateral shear along the northern DSFS with 1σ uncertainties less than 0.7 mm yr−1. These velocities are consistent with an elastic dislocation model with a slip rate of 1.8–3.3 mm yr−1 and a locking depth of 5–16 km. This geodetically determined slip rate is about half of that reported farther south along the central section (Lebanese restraining bend) and the southern section (Jordan Valley and Wadi Araba) of the transform and consequently requires some deformation to occur away from the transform along other geological structures. The factor of two difference in slip rates along the transform is also consistent with differing estimates of total fault slip that have occurred since the mid Miocene: 20–25 km along the northern DSFS (in NW Syria) versus about 45 km along the southern DSFS segment. Some of the strain deficit may be accommodated by north–south shortening within the southwestern segment of the Palmyride fold belt of central Syria. Additionally, a distinct change in velocity occurs within the Sinai plate itself. These new GPS measurements, when viewed alongside the palaeoseismic record and the modest level of present-day seismicity, suggest that the reported estimates of recurrence time of large earthquakes (M > 7) along the northern section of the DSFS may be underestimated owing to temporal clustering of such large historical earthquakes. Hence, a revised estimate of the earthquake hazard may be needed for NW Syria.
Geophysical Journal International, 2003
The Serghaya fault, located approximately along the Syrian–Lebanese border, is a prominent structure within the 200 km restraining bend in the left-lateral Dead Sea fault system. This study documents palaeoseismic and geomorphic expressions of Holocene movements on the Serghaya fault based on trench excavations and radiocarbon dates. Trenches were excavated across and parallel to a 4.5 m fault scarp where Late Pleistocene sediments are faulted against Holocene alluvium and colluvium. Locally oblique slip on the Serghaya fault has produced a sequence of fault-derived colluvial wedges that distinguishes individual palaeoseismic events. In addition, the trench excavations also depict a sequence of buried and displaced channels. Our palaeoseismic study reveals evidence for five surface-rupturing events within the past ∼6500 yr. The last event involved 2–2.5 m of primarily left-lateral displacement and may correspond to one of two historically documented earthquakes during the 18th century (in 1705 and 1759). The displaced channels provide an estimated slip rate of approximately 1.4 ± 0.2 mm yr− 1 during the Holocene. The chronological relationships between the colluvial wedges and faulted channels demonstrate an average left-lateral displacement of about 2 m per event, suggesting that such events correspond to earthquakes of M≳ 7 with a mean return time of about 1300 yr. These results demonstrate that the Serghaya fault may present a previously overlooked earthquake hazard for populations in the vicinity of the AntiLebanon Mountains, including the cities of Damascus and Beirut. In a regional context, the inferred slip rate along the Serghaya fault accounts for about 25 per cent of the total expected motion of Arabia relative to Africa along the Dead Sea fault system. The fact that the Serghaya fault accounts for only a fraction of the expected plate motion implies that the remaining strike-slip and shortening must be accommodated by other active fault branches within the large restraining bend of the Dead Sea fault system. These results contradict suggestions that the northern Dead Sea fault system in Lebanon and Syria is presently inactive as a result of an evolving regional stress field in the eastern Mediterranean region.