late quaternary geological history of the dead sea area israel abstract a 34 5 m borehole which was drilled near the dead sea coast altitude 394 m in the southern part of the fan delta of wadi zeelim reveals the geological history of that area from the latest pleistocene to present the depositional time frame is based on six 14c dates and two u th dates an erosional or nondepositional period is implied by the hiatus between 21 100 yr b p u th age depth 33 m and 11 315 yr b p 14c age depth 32 m a subsequent arid phase is recorded by a 6 5 m thick layer of halite based on 14c dates this phase relates to the abrupt younger dryas cold period reported in temperate to polar regions the fragility of the environment in this region is indicated by the fact that the region experienced such a severe short aridification phase less than 1000 yr evidence of which is found widely in the desert fringes of the middle east and north africa the aragonite found in most of the holocene section indicates that the well site was covered by the lake for most of the holocene exceptions are the intervals at 0 3 and 10 14 m depths which represent low stands of the lake

formation deformation and chertification of systematic clastic dykes in a differentially lithified carbonate multilayer sw iberia algarve basin lower jurassic this work presents original field evidence for tectonically controlled calciclastic dyke injection and subsequent chertification in shelf carbonates during rifting in the south westernmost part of the eurasian continent in the early pliensbachian it is shown by the detailed description of tectonic structures faults and joints stratigraphic discontinuities and by the distribution orientation and morphology of the injected dykes of calciclastic sands into fine grained carbonates that these soft sediment deformation structures were tectonically controlled extensional tectonics developed vertical tensile joints in semi lithified fine grained limestones permitting upward and downward injection of loose calciclastic sands forming clastic dykes the frequency of injection structures along strata was constrained by the thickness of the layer into which the injection was occurring which implies an elastic behaviour however the curvi planar shapes of the dykes and drop like nodules attests the ductile behaviour of the fractured limestones indicating transition from elastic to ductile response to deformation with time the multi layered system consists of just two lithotypes the two display different mechanical behaviours which evolved in time to more brittle conditions as lithification progressed as shown by the cataclastic faulting and jointing of the previously formed soft sediment deformation structures and strata under an analogous stress regime the injection dykes were disrupted by a short lived episode of compression after which tectonic extension resumed still in the lower pliensbachian sometime before the deposition of the upper pliensbachian a pervasive selective event of chertification occurred only the calciclastic sandy layers dykes and nodules were substituted by silica thus enhancing the mechanical contrast between the primary sedimentary structures and the soft sediment deformation structures all the described events occurred during a time interval of approximately 2 myr as constrained by ammonoid stratigraphy

an 8000 year history of landscape climate and copper exploitation in the middle east the wadi faynan and the wadi dana national reserve in southern jordan abstract investigations of geomorphology geoarchaeology pollen palynofacies and charcoal indicate the comparative scales and significance of palaeoenvironmental changes throughout the holocene at the junction between the hyper arid hot wadi arabah desert and the front of the mediterranean belt mountains of edom in southern jordan through a series of climatic changes and episodes of intense mining and smelting of copper ores early holocene alluviation followed the impact of neolithic grazers but climate drove fluvial geomorphic change in the late holocene with a major arid episode corresponding chronologically with the little ice age causing widespread alluviation the harvesting of wood for charcoal may have been sufficiently intense and widespread to affect the capacity of intensively harvested tree species to respond to a period of greater precipitation deduced for the roman byzantine period a property that affects both taphonomic and biogeographical bases for the interpretation of palynological evidence from arid lands with substantial industrial histories studies of palynofacies have provided a record of human and climatic causes of soil erosion and the changing intensity of the use of fire over time the patterns of vegetational climatic change and geomorphic changes are set out for this area for the last 8000 years

the february 11 2004 dead sea earthquake ml 5 2 in jordan and its tectonic implication abstract a moderate sized m w 5 3 earthquake occurred in the dead sea basin on february 11 2004 a rigorous seismological analysis of the main shock and numerous aftershocks suggests that seismogenic structure was a secondary antithetic fault within the dead sea fault system the main shock is well located using all available regional seismic stations and 43 aftershocks were precisely located relative to the main shock using a double difference algorithm the first motion focal mechanism for this earthquake demonstrates nnw sse and ene wsw striking nodal planes and the aftershocks distribution is consistent with the latter indicating a right lateral sense of displacement this orientation and sense of shear are consistent with similarly oriented geological faults around the dead sea basin these structures are likely antithetic faults within the transform system although moderate in size earthquakes that occur very close to the large dead sea fault system warrant consideration in the earthquake hazard assessment of the region for example owing to the proximity to the main fault moderate earthquakes such as this may produce static changes in coulomb stress along the main fault

interpreting soft sediment deformation and mass transport deposits as seismites in the dead sea depocenter we have studied the history of earthquakes over the past 70 kyr by analyzing disturbed sedimentary layers around the margins of the dead sea however we know little about disturbances in the basin depocenter where water depth is 300 m and accessible only by drilling in this study we compare disturbances from the dead sea depocenter with the contemporaneous earthquake record 56 30 ka that was recovered on the western margin of the lake this comparison allows us to discern the characteristics of disturbance in the different subaqueous environments and identify the source and sedimentary process of mass transport deposits our observations indicate that i the long disturbance sequences in the dead sea depocenter are composed of in situ deformation slump and chaotic deposits ii earthquake triggered kelvin helmholtz instability is a plausible mechanism for the in situ deformation in the lake center iii the slump is slope area sourced iv the unit of chaotic deposits is lakeshore sourced and v earthquake triggered slope instability is a viable mechanism for the slump and chaotic deposits we further suggest that long sequences of disturbance in seismically active lake depocenters can be used to infer earthquake clusters

palynology sedimentology and palaeoecology of the late holocene dead sea abstract palynological and sedimentological studies were performed at two holocene profiles in erosion gullies ze elim and ein feshkha which dissect the retreating western shore of the dead sea the aim of the project was to analyse possible links between climate lithology and vegetation development the section in ze elim shows both lacustrine and fluvial sediments whereas sedimentation at ein feshkha is predominantly lacustrine the ze elim profile previously used for paleo lake reconstruction provides an opportunity to compare climate triggered lake levels as paleo hydrological indicators and vegetation history by use of palynology the vegetation development in ze elim and ein feshkha is influenced by both climate and human impact the pollen record of ze elim begins in the pottery neolithic the section of ein feshkha in the late bronze age both records end in the middle ages the ze elim section is characterized by sedimentary hiati between the beginning of the chalcolithic period until the middle bronze age and within the late bronze age settlement periods during the middle bronze age iron age and hellenistic roman byzantine period are indicated by high values of anthropogenic indicators and or mediterranean trees collapses of agriculture which can be related to climate effects are evident during the late bronze age during the iron age and at the end of the byzantine period when the lake level curve indicates arid conditions a comparison of the two pollen records from different environments illustrates a more prominent influence of mediterranean vegetation and cultivated plants in the pollen diagram of ein feshkha the southern dead sea region at the desert fringe is more vulnerable to regional climate change

modeling of seismic guided waves at the dead sea transform 1 on several recordings of linear seismometer arrays crossing the arava fault af in the middle east we see prominent wave trains emerging from in fault explosions which we interpret as waves being guided by a fault zone related low velocity layer the af is located in the arava valley and is considered the principal active fault of the mainly n s striking dead sea transform system in this section observations of these wave trains are confined to certain segments of the receiver lines and occur only for particular shot locations they exhibit large amplitudes and are almost monochromatic we model them by a two dimensional 2 d analytical solution for the scalar wave field in models with a vertical waveguide embedded in two quarter spaces a hybrid search scheme combining genetic algorithm and a local random search is employed to explore the multimodal parameter space resolution is investigated by synthetic tests the observations are adequately fit by models with a narrow only 3 12 m wide waveguide with s wave velocity reduced by 10 60 of the surrounding rock we relate this vertical low velocity layer with the damage zone of the af since the location of receivers observing and of shots generating the guided waves respectively match with the surface trace of the fault the thickness of the damage zone of the af at least at shallow depths seems to be much smaller than in other major fault zones this could be due to less total slip on this fault

earthquake magnitude frequency epicentral distance and soft sediment deformation in sedimentary basins abstract empirical equations available for earthquake magnitude frequency and the maximum epicentral distance of liquefied sites versus magnitude are combined with the characteristic instantaneous sediment deposition rate at a station in a sedimentary basin to form a model for the local stratigraphic frequency of earthquake induced soft sediment deformation structures both the style of sedimentation and the characteristics of the earthquake source combine to determine the pattern of incidence of the structures in a basin the model is probably most directly applicable to the geodynamic interpretation of fluvial basins in which substantial volumes of readily liquefied sands accumulate at high local short term rates

earthquake triggered soft sediment deformation structures seismites in travertine deposits abstract earthquakes related soft sediment deformations seismites are relevant structures to help reconstructing the palaeoseismicity in a region nevertheless although seismites have been described for a large variety of palaeo environments and stratigraphic settings they are rare and in some cases ambiguous structures in this paper we document for the first time impressive seismites affecting a latest quaternary travertine deposit located in southern tuscany serre di rapolano italy these structures are extremely relevant as seismites have been never described for this kind of terrestrial deposits the seismites developed within a 2 5 m thick stratigraphic succession made of alternating terrigenous and carbonate sediments embedded within the travertine deposits earthquake produced liquefaction and fluidization of some terrigenous levels and the injection of fluidized silty sediments dykes and sills into carbonate and terrigenous levels slumped levels and associated decollement surfaces produced highly non cylindrical folds overall induced by the loss of brittle shear strength along the basin slopes the occurrence of these soft sediment deformations implies an important seismic event that took place in a time spam encompassed between 84 8 and 48 92 5 08 ka in an area characterized by low seismicity and scarce knowledge of its seismotectonic setting their spectacular exposition and preservation in saw cuts of an abandoned quarry cava oliviera quarry highlights their relevance and importance

abrupt environmental changes within a late holocene lacustrine sequence south of the marmara sea lake manyas n w turkey possible links with seismic events abstract a coring campaign in lake manyas kus golu on the southern coast of the sea of marmara turkey has provided insights into basin infilling processes during the upper 11 metres of the sedimentary record combined sedimentary features between 5 and 4 m depth have been explained by a seismite a brittle mixed layer uniquely rich in seeds and ostracod valves was widely detected at 4 m downcore this has been interpreted as being the result of a seiche either through a salt inundation linked to a tsunami in the sea of marmara the large scale scenario or a local hydrothermal fluid discharge the small scale scenario ostracod valves which are usually not preserved in lake manyas sediment are either incorporated here as tsunami debris providing a spatially averaged snapshot of the regional assemblage or are locally preserved following a temporary geochemical hydrochemical change of the water of unknown duration but probably several decades the brittle mixed layer overlies cracks resulting from the direct effects of the seismic shock wave on slightly compacted sediment at around 964 cm depth palynological and particle size analyses indicate a change from backswamp to open lacustrine conditions the end of the backswamp has been correlated with a decrease in the level of the sea of marmara from 4000 to 3000 2800 yr ago uncal caused by regional tectonic movements an age depth model is presented based on two ams radiocarbon dates on the palynological detection of the end of the beysehir occupation phase 130 cm above the event and on maximal sedimentation accumulation rates obtained by radionuclide analyses the entire study sequence covers the last 4300 yr the paper examines the possibility of an early byzantine age for the seismic event this may have been the historical event at ad 460 that destroyed cyzicus the ancient erdek 20 km north of the lake and various villages in the interior and was felt widely in the then known world other possibilities include various local and regional events in that same period the early byzantine tectonic paroxysm and the large earthquake in ad 447 that affected the entire sea of marmara region

accuracy of post bomb 137cs and 14c in dating fluvial deposits abstract the accuracy and precision of 137cs and 14c for dating post 1950 alluvial deposits were evaluated for deposits from known floods on two rivers in arizona the presence of 137cs reliably indicates that deposition occurred after intensive above ground nuclear testing was initiated around 1950 there was a positive correlation between the measured level of 137cs activity and the clay content of the sediments although 137cs was detected even in sandy flood sediments with low clay content 137cs is a valuable dating tool in arid environments where organic materials for 14c or tree ring dating are scarce and observational records are limited the 14c activity measured in different types of fine organic detritus yielded dates within 1 to 8 yr of a 1980 flood deposit and the accuracy was species dependent however undifferentiated mixtures of fine organic materials from several post bomb deposits of various ages repeatedly yielded dates between 1958 and 1962 and detrital charcoal yielded a date range of 1676 1939 in semiarid environments the residence time of most types of organic debris precludes accurate annual resolution of post bomb 14c dates

holocene faulting and earthquake recurrence along the serghaya branch of the dead sea fault system in syria and lebanon an edited version of this paper was published in geophysical journal international by blackwell publishing blackwell publishing retains the copyright copyright 2003 blackwell publishing see also http www blackwell synergy com doi abs 10 1046 j 1365 246x 2003 01933 x http atlas geo cornell edu deadsea publications gomez2003 gji htm

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

the structure of the dead sea basin abstract the dead sea basin is located along the left lateral transform boundary between the arabian and sinai plates its structure and history are known from surface geology drilling seismic reflection and other geophysical data the basin comprises a large pull apart almost 150 km long and mostly 8 10 km wide which is flanked by a few kilometres wide zones of normal faulting the basin formed at about 15 ma or earlier close to the beginning of the transform motion and it reached about half its present length before the end of the miocene a strong negative gravity anomaly records a thick sediment basin fill 5 km under half its length reaching a maximum of 10 km the fill includes a few km of salt ca 6 4 ma which forms several diapirs at any one time large parts of the basin subsided simultaneously but the site of fastest subsidence seems to have shifted northward sedimentation rates reached at least hundreds of metres per million years or more in the miocene and 1 km myr in later periods the basin structure is dominated by longitudinal faults intrabasinal faults which delimit the pull apart and which are the extensions of the major strike slip faults north and south of the basin and normal faults which extend along the basin margins the latter faults express a small component of extension across the basin whereas the pull apart resulted from the much larger lateral motion along the basin in addition transverse faults divide the pull apart into several segments with somewhat different histories the pull apart grew by becoming longer parallel to the transform motion at shallow levels this was probably achieved by normal slip on transverse listric faults while the fill between them was little deformed the crust under the basin was stretched and thinned during basin lengthening which caused its subsidence basin formation was accompanied by uplifting of its flanks by 1 km sparse igneous activity occurred along the basin and its flanks its presence suggests a thermal anomaly in the lower lithosphere beneath the basin and adjacent parts of the transform

soft sediment deformation within seismogenic slumps of the dead sea basin abstract the late pleistocene lisan formation preserved next to the dead sea provides exceptional 3 d exposures of folds and faults generated during soft sediment slumping and deformation it is possible to generate a range of four different scenarios associated with overprinting in a single slump event the progressive evolution of slump systems may be broadly categorised into initiation translation cessation relaxation and compaction phases thrust packages typically define piggyback sequences during slump translation with back steepening of imbricate faults leading to collapse of folds back up the regional palaeoslope detailed evaluation of slumped horizons may also permit structures to be traced across apparently separate and distinct slumped units the recognition that slumps may be reworked by younger seismically triggered events suggests that in some cases the seismic recurrence interval may be shorter than previously anticipated

distributed fault slip model for the 2011 tohoku oki earthquake from gnss and grace goce satellite gravimetry the gravity recovery and climate experiment grace mission launched 2002 and the gravity field and steady state ocean circulation explorer goce mission march 2009 to november 2013 collected spaceborne gravity data for the preseismic and postseismic periods of the 2011 tohoku oki earthquake in addition the dense japan geonet global navigation satellite systems gnss network measured with approximately 1050 stations the coseismic and postseismic surface displacements we use a novel combination of gnss grace and goce observations for a distributed fault slip model addressing the issues with gravimetric and geometric change over consistent time windows our model integrates the coseismic and postseismic effects as we include goce observations averaged over a 2 year interval but their inclusion reveals the gravity change with unprecedented spatial accuracy the gravity gradient grid evaluated at goce orbit height of 265 km has an estimated formal error of 0 20 me which provides sensitivity to the mainly coseismic and integrated postseismic induced gravity gradient signal of 1 03 me we show that an increased resolution of the gravity change provides valuable information with goce gravity gradient observations sensitive to a more focused slip distribution in contrast to the filtered grace equivalent the 2 year averaging window of the observations makes it important to incorporate estimates of the variance covariance of unmodeled processes in the inversion the gnss and grace goce combined model shows a slip pattern with 20 m peak slip at the trench the total gravity change 200 gal and the spatial mapping accuracy would have been considerably lower by omitting the goce derived fine scale gravity field information

internal structure of the dead sea leaky transform rift in relation to plate kinematics abstract the structures along the dead sea transform rift are related to the motions of the sinai and arabia plates which border it and to the irregularities of their boundaries the total slip was 105 km left lateral but the present structures were formed mainly during the last 40 km of slip which probably occurred in the plio pleistocene along the southern half of the transform the strike slip motion takes place on en echelon faults this produces rhomb shaped grabens or pull aparts which are sometimes composite and in which there is local crustal separation thus much of the transform is leaky these structures occur in a morpho tectonic rift valley delimited by normal faults which express a small component of transverse extension along a few segments the shape of the transform is such that lateral motion produces local transverse compression the geometric relations of the structures along the transform define an eulerian pole of relative plate motions at 32 8 n 22 6 e 0 5 the older motion was somewhat different and is described by a pole located about 5 west of the above then the component of transverse extension and crustal separation was much smaller than now while local transverse compression was more important the northern half of the dead sea transform has an irregular shape and the bordering plates did not remain rigid as lateral motion continued here transverse compression is often important

using palynology to re assess the dead sea laminated sediments indeed varves lacustrine laminated sediments are often varves representing annual rhythmic deposition the dead sea high stand laminated sections consist of mm scale alternating detrital and authigenic aragonite laminae previous studies assumed these laminae were varves deposited seasonally however this assumption has never been robustly validated here we report an examination of the seasonal deposition of detrital aragonite couplets from two well known late holocene laminated sections at the ze elim fan delta using palynology and grain size distribution analyses these analyses are complemented by the study of contemporary flash flood samples and multivariate statistical analysis because transport affects the pollen preservation state well preserved mostly air borne transported pollen was analysed separately from badly preserved pollen and fungal spores which are more indicative of water transport and reworking from soils our results indicate that i both detrital and aragonite laminae were deposited during the rainy season ii aragonite laminae have significantly lower reworked and fungal spore concentrations than detrital and flash flood samples and iii detrital laminae are composed of recycling of local and distal sources with coarser particles that were initially deposited in the dead sea watershed and later transported via run off to the lake this is in line with previous carbon balance studies that showed that aragonite precipitation occurs after the massive input of tco2 associated with run off episodes consequently at least for the holocene ze elim formation laminated sediments cannot be considered as varves older quaternary laminated sequences should be re evaluated

paleovan international continental scientific drilling program icdp site survey results and perspectives lake van is the fourth largest terminal lake in the world volume 607 km 3 area 3570 km 2 maximum depth 460 m extending for 130 km wsw ene on the eastern anatolian high plateau turkey the sedimentary record of lake van partly laminated has the potential to obtain a long and continuous continental sequence that covers several glacial interglacial cycles ca 500 kyr therefore lake van is a key site within the international continental scientific drilling program icdp for the investigation of the quaternary climate evolution in the near east paleovan as preparation for an icdp drilling campaign a site survey was carried out during the past years we collected 50 seismic profiles with a total length of similar to 850 km to identify continuous undisturbed sedimentary sequences for potential icdp locations based on the seismic results we cored 10 different locations to water depths of up to 420 m multidisciplinary scientific work at positions of a proposed icdp drill site included measurements of magnetic susceptibility physical properties stable isotopes xrf scans and pollen and spores this core extends back to the last glacial maximum lgm a more extended record than all the other lake van cores obtained to date both coring and seismic data do not show any indication that the deepest part of the lake tatvan basin ahlat ridge was dry or almost dry during past times these results show potential for obtaining a continuous undisturbed long continental palaeoclimate record in addition this paper discusses the potential of paleovan to establish new results on the dynamics of lake level fluctuations noble gas concentration in pore water of the lake sediment history of volcanism and volcanic activities based on tephrostratigraphy and paleoseismic and earthquake activities c 2009 elsevier ltd all rights reserved

injection mechanism of clay rich sediments into dikes during earthquakes 1 clastic dikes may form by simultaneous fracture propagation in rocks and injection of clastic material into the fractures resulting from strong seismic shaking we studied the mechanisms of clastic dike formation within the seismically active dead sea basin where hundreds of clastic dikes cross cut the soft rock of the late pleistocene lacustrine lisan formation we analyzed the anisotropy of magnetic susceptibility ams of dikes with known formation mechanisms and defined the characteristic ams signatures mainly of dikes developed by injection process most of the dikes were emplaced due to fluidization of clay rich sediment and are characterized by triaxial ams ellipsoids the dominant triaxial ams ellipsoids along the dike widths suggest that the fluidization mechanism of clay rich sediment is different from the known liquefaction process of sand the ams analysis supported by field evidence indicates that the injection of clay rich sediment is characterized by two main regimes 1 vertical flow characterized by subvertical v2 axes and subhorizontal v1 and v3 axes the v2 axes may indicate the flow directions during fast flow 2 horizontal slow flow characterized by subvertical v3 axes and subhorizontal v1 and v2 axes a streaked ams pattern mainly composed of v2 and v3 axes represents a turbulent flow that generated local eddies simultaneously with the clastic transport the ams parameters along the dikes and possible grain imbrications along dike walls support organization of grains under high strain rates this application of the ams method provides a petrofabric tool for identifying seismites and inferring their flow kinematics in complex geologic areas

seismically triggered soft sediment deformation structures close to a major strike slip fault system in the eastern alps hirlatz cave austria abstract we investigate episodic soft sediment deformation structures cross cut by normal faults preserved in unlithified finely laminated calcite rich sediments in the hirlatz cave in the northern calcareous alps austria these sediments comprise varve like alternations of brighter carbonate quartz rich layers and darker clay mineral rich layers the deformed sediments contain abundant millimeter to centimeter scale soft sediment structures load casts ball and pillow structures sheet slumps thrust faults and folds erosive channels filled with slides and chaotic slumps after deposition and soft sediment deformation normal faults developed within the entire sedimentary succession an event that probably correlates with an offset of c 10 cm of the passage wall above the outcrop our major conclusions are i the sediments have a glacial origin and were deposited in the hirlatz cave under phreatic fluvio lacustrine conditions the deposition and the soft sediment deformation occurred most likely during the last glaciation i e around 25 ka ago ii the liquefaction and formation of the soft sediment structures in water saturated stratified layers was triggered by episodic seismic events iii the internally deformed sediments were later displaced by normal faults iv a possible source for the seismic events is the active sinistral salzach ennstal mariazeller puchberger semp strike slip fault which is located about 10 km south of the outcrop and plays a major role in accommodating the extrusion of the eastern alps towards the pannonian basin to our knowledge the described structures are the first report of liquefaction and seismically induced soft sediment deformations in quaternary sediments in the eastern alps

episodic behavior of the jordan valley section of the dead sea fault inferred from a 14 ka long integrated catalog of large earthquakes 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 120 km 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

high resolution geological record of historic earthquakes in the dead sea basin a 2000 year paleoseismic record of the dead sea area was recovered from a lacustrine sedimentary section the section is being exposed at the ze elim terrace on the shores of the dead sea due to the fast retreat of the lake the section consists of laminated detrital and chemical mainly aragonite sediments that were deposited in the holocene paleo dead sea eight layers in the section show deformed sedimentary structures and are identified as seismites their chronology was determined by radiocarbon dating on organic remains the seismite ages are well correlated with the historically documented earthquakes of 64 and 31 b c and 33 363 1212 1293 1834 and 1927 a d the few historically documented earthquakes that have no correlatives in the ze elim seismite record occurred in times of sedimentary hiatuses at this site e g 749 a d based on modern analogues and the association of similar disturbed layers with syndepositional faults the ze elim terrace seismites indicate m 5 5 earthquakes the average recurrence interval is estimated as 100 300 years and represents slip events on different faults in the dead sea area the ze elim section provides a unique opportunity to correlate two independent and extensive data sets the historical and sedimentary records this study opens the way for better understanding of spatial and temporal distribution of earthquakes along the dead sea transform and elsewhere

seismic behaviour of the dead sea fault along araba valley jordan the dead sea fault zone is a major left lateral strike slip fault south of the dead sea basin the wadi araba fault extends over 160 km to the gulf of aqaba the dead sea fault zone is known to have produced several relatively large historical earthquakes however the historical events are unequally distributed along the fault and only four events have been reported in the araba valley over the last few thousands of years magnitudes estimated from the historical record are probably slightly smaller than that of the m w 7 3 earthquake that struck the gulf of aqaba in 1995 the fault cuts straight across pleistocene to holocene alluvium and shows morphologic evidence for essentially pure strike slip motion regional seismic monitoring reveals little microseismicity along the fault except around the dead sea and gulf of aqaba where the fault splays into complex pull apart basin fault systems we have investigated the fault zone at several sites selected from spot images and the study of aerial photography at the site of the now destroyed tilah castle a well preserved wall dated to be about 1200 yr bp 14 c age on charcoal is cut by the fault and offset by 2 2 m comparison with offset gullies at a nearby site 3 km to the north and at three other sites respectively 25 50 and 65 km to the south reveals that this specific fault displacement is probably related to the last seismic event that ruptured that fault segment possibly in ad 1458 moreover the offset gullies suggest a characteristic slip behaviour with recurring slip of about 1 5 m on average given the 4 2 mm yr 1 slip rate derived for this fault segment we infer that the fault should produce m w 7 earthquakes along some segment in the araba valley about every 200 years the historical period with only four well documented large earthquakes in ad 1068 ad 1212 ad 1293 and ad 1458 thus appears to have been relatively quiescent with a 20 per cent deficit of m w 7 earthquakes however our data do not exclude the possibility of larger m w 7 6 earthquakes or time clustering of earthquakes over longer timespans an alternative seismic behaviour involves m w 7 6 earthquakes about every 6000 years and m w 7 earthquakes about every 250 years the historical catalogue would then appear to be complete for m w 7 earthquakes

micropaleontological and taphonomic characteristics of mass transport deposits in the northern gulf of eilat aqaba red sea abstract submarine mass transport deposits mtds are a well known phenomenon in tectonically active regions evidence for such deposits is commonly found in the continental slope sedimentary records as distinct units with coarser grain size compared to the usual and continuous pelagic sedimentation the gulf of eilat aqaba is located between the southernmost end of the dead sea transform and the spreading center of the red sea and is considered as an active tectonic region in this study an innovative approach using symbiont bearing larger benthic foraminifera lbf to identify mtds in the gulf of eilat aqaba gea sedimentary record is presented the abundance size and preservation state of lbf shells were analyzed in two radiocarbon dated sediment cores collected at different deposition environments at water depth of 532 m and 316 m the microfaunal and taphonomic results show that the coarse units are characterized by a generally higher numerical abundance of lbf dominated by operculina ammonoides amphistegina papillosa and amphistegina bicirculata these benthic assemblages are found in deeper depths than their original habitat ranging between 50 and 120 m in accordance with their symbionts light requirements in the coarse units lbf 1 mm appear in high frequency up to 161 specimens per g sediment and poorly preserved shells are also abundant containing up to 247 specimens per g sediment in addition these units also contain high numbers of yellowish and blackish colored lbf shells as opposed to null in the non disturbed units and unlike their natural white color the large shell size indicates that high energy is involved in the displacement of the sediments the poor state of preservation also suggests a turbulent flow during transportation which requires a high energy triggering mechanism the color alteration is probably associated with a diagenetic process related to increasing burial time depth also supported by the stratigraphic older ages of the mtds suggesting a long burial before the sediments were displaced in addition according to the dating of the record some units correlate with historical and pre historical earthquakes reinforcing lbf species as a reliable proxy for mass transport events

geomorphological response of the lower jordan river basin to active tectonics of the dead sea transform abstract the lower jordan river ljr basin has been shaped on an active tectonic segment of the dead sea transform dst the jordan valley fault jvf which remains relatively unexplored due to its rough terrain conditions hyper arid climate and location along a political border where minefields are common the ability to detect the morphology of the valley surface by remote sensing methods provides an opportunity to follow the complex tectonic structure of the ljr basin and the spatial and temporal geomorphic processes that have shaped the basin since its exposure in the early holocene after the desiccation of lake lisan 14 5 ky bp in this study we use gis analyses and image processing to explore the relation between the geomorphology of the ljr basin and the active tectonics of the jvf the morphometric fluvial parameters of the basin are interpreted in relation to mapped faults geophysical gravity interpolation and seismic data we introduce morphometric gravity relations that show an increasing trend of the morphometric parameters standard deviation std as a function of the gravity anomaly increase which are consistent with stream power formulation studies and seismic measurements our results show that the active tectonics of the jvf is concentrated towards the basin s center and the dead sea fault location and that at the borders of the gravity highs sinuosity slope and width changes together with recent seismic activity all suggest on tectonic uplifting and active faulting in those areas

chronology of relict lake deposits around the suwalong paleolandslide in the upper jinsha river se tibetan plateau implications to holocene tectonic perturbations abstract the suwalong paleolandslide is located in the batang zhongza reach of the upper jinsha river at the southeast margin of the tibetan plateau where tectonic activity is very strong and has formed a great deal of large paleolandslides or their relicts the relict deposits that have been exposed around the suwalong paleolandslide provide an opportunity to understand the formation process and potential origin of a former landslide dammed lake in the active belt region two level platforms of ancient dammed lake deposits were found on both the upstream and downstream sides of the relict landslide dam the chronology of the landslide and its surrounding relict lake deposits were studied by using 14 c dating and osl dating the minimum age of the suwalong landslide blocking the jinsha river was shown to be about 1355 yr bp and those of its surrounding two platforms of lacustrine sediments were shown as 1 8 and 1 3 ka bp the recordings of the soft sediment deformations induced by seismic liquefaction were found in the dammed lake sediments thus providing substantial evidence for the existence of the paleoseismic events we can infer that the suwalong landslide may have been triggered by a paleoearthquake or combination of paleoearthquake and rainfall events the chronology of the landslide dammed lake deposits around the relict suwalong landslide dam reveals that the large scale landslides in the batang zhongza reach of the upper jinsha river were formed during numerous periods namely the large scale landslides may have been triggered by several paleoearthquake events occurring at around 1900 1355 and 1115 yr bp indicating that the jinsha river faults in the area may have been quite active since the late holocene

soft sediment deformation structures from the diexi paleo dammed lakes in the upper reaches of the minjiang river east tibet abstract the north south trending upper reaches of the minjiang river run along the longmen shan min shan fault zone a zone of abrupt topographic change along the eastern margin of the tibetan plateau multiple levels of well preserved soft sediment deformation structures seismites occur in sediments deposited in paleo dammed lakes in the upper part of the minjiang river valley these deformation structures include liquefied convolute deformation water escape structures flame structures pseudonodules ball and pillow structures sedimentary dykes mud lenses and large scale folds several kilometers from the barrier bar of the diexi paleo dammed lakes seven deformed structural layers were identified at different heights in late quaternary stratigraphic sequences near shawan village maoxian county analyses of the deformation structures landforms and the structural environment indicate that these deformation structures were caused by earthquakes slumps and landslides osl optical stimulated luminescence and 14c dating of soft sediment layers from the shawan site indicate that intense earthquakes occurred during the period 25 20 ka b p therefore accurate geological dating of deformed features in dammed lake deposits in high mountains and canyons enables the record of moderate to large magnitude earthquakes to be extended to the late pleistocene holocene upon the eastern tibetan plateau

four thousand years of seismicity along the dead sea rift a study of major earthquake occurrence along the dead sea transform 35 5 36 5 e 27 2 37 5 n during the past four millenia has been attempted geological archaeological biblical historical and seismological evidence were integrated in an effort to quantify the space time distribution of seismicity in the said province the overall earthquake activity in the conterminous near east indicates a stable pattern and appeared to have been stationary over the examined time window about 110 earthquakes in the magnitude range 6 7 ml 8 3 affected the area during the past 2500 years of these 42 originated along the dead sea fault system itself while 68 were imported from the helenic cyprian arcs and the anatolian elburz zagros fault systems these events were responsible for the repeated destruction of many cultural centers in the dead sea region proper the major seismic activity since 2100 b c e before christian era has been confined to the vicinity of its eastern shore with extremal seismicity at its southern tip near the prehistorical site of bab a dara a 31 15 n 35 32 e this may constitute the first solid evidence that the biblical cities of the plain sodom gommorah etc were located there recent studies of earthquake deformations in the lisan deposits near bab a dara a agree with our findings at the present time a magnitude 6 earthquake is pending at the northern edge of the levant rift with its average recurrence interval 83 years exceeded by one standard deviation 32 years

soft sediment deformation by kelvin helmholtz instability a case from dead sea earthquakes abstract the standard explanation for soft sediment deformation is associated with overturn of inverted density gradients however in many cases observations do not support this interpretation here we suggest an alternative in which stably stratified layers undergo a shear instability during relative sliding via the kelvin helmholtz instability khi mechanism triggered by earthquake shaking dead sea sediments have long stood out as a classical and photogenic example for recumbent folding of soft sediment these billow like folds are strikingly similar to khi structures and have been convincingly tied to earthquakes our analysis suggests a threshold for ground acceleration increasing with the thickness of the folded layers the maximum thickness of folded layers order of decimeters corresponds to ground accelerations of up to 1 g such an acceleration occurs during large earthquakes recurring in the dead sea

prehistoric earthquake deformations near masada dead sea graben earthquake inducedfluidizations and suspensions of lake sediments associated with syndepositionalfaults formapaleoseismicrecordinthedeadseagraben theassociation offluidized beds with surface faulting supports the recognition of mixed layers as reliable earthquake indicators and provides a tool for the study of very long term 70 kar seismicity along the dead sea transform the faults compose a fault zone that offsets laminated sediments of the late pleistocene lake lisan they exhibit displacements of as much as 2 m layers of massive mixtures of laminated fragments are interpreted as disturbed beds each formed by an earthquake the undisturbed laminated layers between these mixed layers represent the interseismic interval a typical vertical slip of about 0 5 m per event is separated by several hundred years of quiescence the fault zone lies within the dead sea graben 2 km east of masada where archaeology and historical accounts indicate repeated strong earthquake damage the distribution of strikes in the fault zone resembles that of the faults exposed in and around the graben including the seismogenic ones the excellent exposures over hundreds of metres allow an unprecedented temporal and spatial resolution of slip events on faults

effects of strong seismic shaking in lake sediments and earthquake recurrence interval temiscaming quebec the magnitude 6 3 timiskaming earthquake of 1935 resulted in discoloration in small lakes in the epicentral region sonar profiles for lac tee have shown that organic rich gyttja has been removed from the sides and redeposited in the deep parts of the lake lake sediment cores from deep basins contain a 2 3 cm uppermost layer which is interpreted as the normal accumulation of sediment since 1935 this is followed by a 20 cm chaotic zone of black gyttja mixed with partly tabular fragments of a previously formed silt layer underlain by a dense 1 2 cm thick silt horizon the latter is interpreted as having formed by rapid settling of the denser silicate portion of the resuspended sediment this 20 cm zone is insufficient to account for the abnormal thickness of gyttja in the basins so events of this kind would have had to have occurred repeatedly since deglaciation the only major prehistoric event revealed by these 100 cm cores is at a depth equivalent to about 1500 years ago based on the amount of sed

holocene earthquakes inferred from a fan delta sequence in the dead sea graben abstract the holocene sequence of the fan delta of nahal darga in israel records deformation associated with earthquakes related to the dead sea transform in general and to the jericho fault in particular the fan delta sequence is well exposed and 20 radiocarbon ages help to date the earthquakes that are inferred from a displacement along faults b liquefaction features associated with 11 separate sandy and silty layers and c slumped allocthonous bodies of sediments located directly above one of the main splays of the jericho fault on average an earthquake larger than m 5 5 has occurred approximately every 600 years this estimate is based on the earthquake record of the complete stratigraphic sequence with erosional hiatuses omitted from the calculations the most recently deformed layer is related to the 1927 jericho m l 6 2 earthquake this layer provides a modern analog for the style of soft sediment deformation associated with earthquakes in the late pleistocene and holocene silty sand beds of the fan delta complexes of the dead sea and its predecessor lake lisan

active faulting in the dead sea rift abstract manifestations of late quaternary and holocene faulting were studied in a 500 km long segment of the dead sea transform rift most prominent are left slip faults whose characteristic physiographic features are recognizable along most of the studied segment where these faults bend or are stepped to the left rhomb shaped grabens or pull aparts are produced forming depressions in the reverse situation compressional features such as pressure ridges domes and folds form positive topographic features such structures are combined on a variety of scales ranging from a few hundred meters long to tens of kilometers normal faults sub parallel to the left slip faults produce a trough like valley along much of the dead sea transform but are most prominent along the margins of the large rhomb grabens e g the dead sea trough they apparently record a small component of transverse extension generally their motion is slow young slip did not occur along some segments during the last few 10 4 y elsewhere throws of 10 20 m at least occurred in this period the dead sea transform is seismically active the instrumental and historic records indicate a seismic slip rate of 0 15 0 35 cm y during the last 1000 1500 y while estimates of the average pliocene pleistocene rate are 0 7 1 0 cm y either much creep takes place or the slip rate varies over periods of a few 10 3 y

quantitative analysis of seismogenic shear induced turbulence in lake sediments spectacular deformations observed in lake sediments in an earthquake prone region lisan formation pre dead sea lake appear in phases of laminar moderate folds billow like asymmetric folds coherent vortices and turbulent chaotic structures power spectral analysis of the deformation indicates that the geometry robustly obeys a power law of 1 89 similar to the measured value of kelvin helmholtz kh turbulence in other environments numerical simulations are performed using properties of the layer materials based on measurements of the modern dead sea sediments which are a reasonable analogue of lake lisan the simulations show that for a given induced shear the smaller the thickness of the layers the greater is the turbulent deformation this is due to the fact that although the effective viscosity increases the reynolds number decreases the bulk richardson number becomes smaller with decrease in the layer thickness the latter represents the ratio between the gravitational potential energy of the stably stratified sediments and the shear energy generated by the earthquake therefore for thin layers the shear energy density is larger and the kh instability mechanism becomes more efficient the peak ground acceleration pga is related to the seismogenic shear established during the earthquake hence a link is made between the observed thickness and geometry of a deformed layer with its causative earthquake9s pga

pollen analysis of core ds7 1sc dead sea showing intertwined effects of climatic change and human activities in the late holocene the dead sea sediment holds the archives of a complex relationship between ever changing nature and ancient civilisations here the detailed pollen analyses of core ds7 1sc off ein gedi are presented for the first time the record covers the last 2500 years the facies changes from halite when no freshwater flows in the dead sea to laminites when rainfall provides sufficient inflow for the jordan and subsidiary rivers a couple of times through the record the pollen diagram supported by the facies change shows a wetter roman byzantine period which allowed intensive arboriculture and a wetter period at the end of the xixth and beginning of the xxth centuries the latter in good relation with historical and instrumental data based on radiocarbon chronologies on several pollen diagrams along the western dead sea shore the transition to drier climates and the transition to pastoralism are suggested to take place between a few decades before the islamic period and close to this transition a high resolution palynological study of the individual laminae forming the laminites aragonite and gypsum in the summer versus detritics in winter confirms the seasonal character of the laminae but throws a note of caution as for their regular annual character

sedimentary earthquake records in the izmit gulf sea of marmara turkey abstract sedimentary earthquake records of the last 2400 a including that of the devastating 17 august 1999 izmit earthquake mw 7 4 were studied in cores from the 210 m deep central karamursel basin of the izmit gulf in the eastern sea of marmara using laser grain size physical properties stable o and c isotopes and xrf core scanner analyses and dated by radionuclide and radiocarbon methods the earthquake records are represented by turbidite homogenite mass flow units thu that commonly contain a basal coarse layer a middle laminated silt layer and an overlying homogeneous mud layer the coarse basal part has a sharp and sometimes scoured lower boundary and includes multiple coarse sand silt layers or laminae showing normal size grading multiple coarse layers and occasional bi directional cross bedding suggest deposition from a bed load during water column oscillations or seiche effect the grain size characteristics of the overlaying laminated silt and the homogeneous mud units indicate deposition from weak oscillating currents and homogeneous suspension respectively high mn value just below the base of thus suggests diagenetic enrichment at oxic anoxic redox boundary before the mass flow event sharp decrease in mn with very low values within the thus suggests transient redox conditions following the mass flow variable geochemical compositions of the basal coarse layers indicate different sediment sources for different thus eight sedimentary earthquake records observed in the last 2400 a in the izmit gulf can be confidently correlated with the historical earthquakes of 1999 1509 ad ms 7 2 1296 ad i vii 865 ad i viii 740 ad i viii 268 ad i viii 358 ad i ix and 427 bc this gives an earthquake recurrence time of ca 300 a with the interval between consecutive events ranging from 90 to 695 a

historic dead sea level fluctuations calibrated with geological and archaeological evidence abstract the dead sea the holocene terminal lake of the jordan river catchment has fluctuated during its history in response to climatic change biblical records calibrated by radiocarbon dated geological and archaeological evidence reinforce and add detail to the chronology of the lake level fluctuations there are three historically documented phases of the dead sea in the biblical record low lake levels ca 2000 1500 b c e before common era high lake levels ca 1500 1200 b c e and low lake levels between ca 1000 and 700 b c e the biblical evidence indicates that during the dry periods the southern basin of the dead sea was completely dry a fact that was not clear from the geological and archaeological data alone

continental transforms a view from the alpine fault abstract continental transform faults are dominantly highly localized strike slip shear zones hundreds of kilometers long that accumulate tens to hundreds of kilometers of displacement from work on the alpine fault we pose the questions what is the deep structure of a continental transform and how does the displacement become localized we review research on the alpine fault and propose a model in which the fault partitions at depth into a steep zone extending into the mantle with largely fault parallel motion and a flat ductile decollement in the lower crust the fault localizes around two thirds of the plate motion within a 100 km wide zone of distributed deformation a review of other active continental fault systems suggests that variation between them may reflect their tectonic origins the nature of the crust in which they develop the presence of a significant oblique component of motion and the displacement rate all however have evidence for the development of a single principal fault zone that carries 50 of the total displacement and extends as a localized zone of shear into the upper mantle we review mechanisms of strain weakening and suggest that localization of a principal fault may be initiated in the seismogenic crust and through a series of positive feedbacks eventually extend through the lower crust into the upper mantle

zones of inelastic deformation around surface ruptures detected by magnetic fabrics abstract characterizing the inelastic strain field around co seismic faults is a key to understanding earthquake rupture processes we aim to detect zones of inelastic deformation around surface ruptures using anisotropy of magnetic susceptibility ams analyses to characterize the paleo seismic setting we measured 29 normal faults which cut the late pleistocene lacustrine lisan formation and were associated with shallow

characterization of land degradation along the receding dead sea coastal zone using airborne laser scanning abstract the dead sea the lowest place on the earth s continents was at its highest level in 1896 reaching an elevation of 388 4 m below mean sea level m b m s l and 390 m in the early 1920s since then it has almost constantly been dropping reaching the level of 426 m b m s l in 2013 since the late 1990s its level has been decreasing by approximately 1 my 1 the rapid lake retreat accelerates large scale environmental deterioration including soil erosion land degradation rapid headcut migration and widespread development of collapse sinkhole fields these geomorphic elements threaten the natural environment and anthropogenic infrastructure we provide an overview of the geomorphic processes in the form of soil erosion channel incision land degradation and the development of collapse sinkholes we take advantage of the high resolution airborne laser scanning technology for three dimensional detection of surficial changes quantification of their volumes and documentation of the present state of the terrain with utmost accuracy and precision this type of information and the identification of future trends are vital for proper planning of any rapidly changing environment

strontium isotopic chemical and sedimentological evidence for the evolution of lake lisan and the dead sea precise strontium isotope ratios combined with chemical analyses and sedimentological information are used to monitor the water sources and the evolution of the dead sea and its late pleistocene precursor lake lisan 70 18 kyr b p the materials analyzed include bulk aragonite water leached soluble salts and residual aragonite and gypsum from the lisan formation in the perazim valley near the sw shore of the dead sea the residual aragonite and the associated soluble salts display systematic fluctuations in 17sr86sr ratios between 0 70803 and 0 70806 and from 0 70805 to 0 70807 respectively in individual soluble salt residual aragonite pairs the soluble salt displays a higher 87sr86sr ratio gypsum samples yield 17sr86sr ratios similar to the soluble salts from adjacent layers in the section this shows that in individual samples the source of sr in aragonite was distinct from that in soluble salts and the gypsum the sterility of the lisan sediments their strictly nonbioturbated fine lamination and their high content of chloride salts indicate that lake lisan was a saline or even hypersaline water body in the absence of alternative sources of hco3 and s042 the abundance of primary aragonite and gypsum in the lisan column reflects an import of very large volumes of freshwater into the otherwise saline lake resulting in a density stratification of this water body the history of the upper water layer and that of the lower brine is reflected in the chemical and strontium isotope composition of the aragonite and in that of the associated soluble salts and in the gypsum samples respectively whereas the bicarbonate and much of the ca2 required for aragonite crystallization were supplied by the freshwater the complementary ca2 and sr 2 were added by the lower brine the upper water layer of lake lisan acted as a so42 capacitor during the lake s rise periods it was removed therefrom as prominent gypsum beds upon climatic induced drier period mixing or even complete overturn of the lake the evolution of lake lisan took place between two distinct modes the first was characterized by an extensive supply of freshwater and resulted in a rise of the lake s level a density layered structure and precipitation of aragonite the second mode was marked by a diminishing freshwater input resulting in mixing or complete overturn of its water and precipitation of gypsum these two modes reflect the climatic evolution of the region in the late pleistocene which fluctuated between drier and wetter periods the transition to the holocene is accompanied by the dry up of lake lisan and its contraction to the present dead sea

landscape development in an hyperarid sandstone environment along the margins of the dead sea fault implications from dated rock falls in this study we explored the spatial and temporal relations between boulders and their original in situ locations on sandstone bedrock cliffs thiswas accomplished bycombining field observations withdating methods using cosmogenicisotopes 10 be and 14 c and optically stimulated luminescence osl our conclusions bear both on the landscape evolution and cliff retreat process in the hyperarid region of timna and on the methodology of estimating exposure ages using cosmogenic isotopes we recognize three discrete rock fall events at 31 ka 15 ka and 4 ka in this hyperarid region the most plausible triggering mechanism for rock fall events is strong ground acceleration caused by earthquakes generated by the nearby dead sea fault dsf our record however under represents the regional earthquake record implying that ongoing development of detachment cracks prior to the triggering event might be slower than the earthquake cycle cliff retreat rates calculated using the timing of rock fall events and estimated thickness of rock removed in each event range between 0 14 m ky 1 and 2 m ky 1 when only full cycles are considered we derive a more realistic range of 0 4 m ky 1 to 0 7 mk y 1 these rates are an order of magnitude faster than the calculated rate of surface lowering in the area we conclude that sandstone cliffs at timna retreat through episodic rock fall events that preserve the sharp imposing landscape characteristic to this region and that ongoing weathering of the cliff faces is minor a 10 20 difference in the 10 be concentrations in samples from matching boulder and cliff faces that have identical exposure histories and are located only a few meters apart indicates that cosmogenic nuclide production rates are sensitive to

a seismite in triassic gypsum deposits grabfeld formation ladinian southwestern germany an approximately 1 m thick gypsum bed and its underlying 45 cm dolomite bed with variable soft sediment deformation structures are described from the grundgips member of the grabfeld formation middle keuper ladinian in southwestern germany the deformation structures are mainly convolutions folds cusps domes and off shooting dykes and less common brecciation or faulting these deformation structures are interpreted to be caused by liquefaction and or fluidization of the semiconsolidated sediments by a seismic shock of approximately magnitude 6 7 palaeoseismicity is thought to be related with a nearby wrench fault system associated with a major suture zone of the variscan basement

calibration of the 14c time scale to 40 ka by 234u 230th dating of lake lisan sediments last glacial dead sea a new comparison of 14c dates with 234u 230th ages is presented of aragonites from lake lisan the last glacial dead sea between 20 52 cal ka bp the lisan data are coincident with the coral based 14c calendar age calibration through the continuous portion of the curve to 23 5 cal ka bp and with the additional checkpoints at 30 and 40 cal ka bp the agreement with the corals provides evidence for the accuracy of the u th and 14c ages and indicates that lisan aragonites can potentially be used to generate a nearly continuous record of the atmospheric 14c variations through this crucial time interval the lisan data are compared with other records older than 25 cal ka bp from lake suigetsu japan north atlantic foraminifera south african cave deposits and tufa from spain over some age intervals the records show broad agreement over other intervals they diverge all agree that 14c ages were 2 5 0 5 ka younger than calendar ages between 20 32 cal ka bp for ages 32 cal ka bp the lake suigetsu data indicate small differences between 14c ages and calendar ages of less than 1 5 ka the other records broadly agree that 14c ages are too young by 3 1 ka from 32 39 cal ka bp at 40 cal ka bp the foraminifera show equal 14c and calendar ages while the corals lisan aragonites and the spanish tufa indicate a large age difference of 4 5 ka a recent paleomagnetic study of the lisan formation indicates that the high calendar 14c age difference at 40 cal ka bp may be associated with the laschamp paleomagnetic excursion

lake levels and sequence stratigraphy of lake lisan the late pleistocene precursor of the dead sea lake lisan the late pleistocene precursor of the dead sea existed from 70 000 to 15 000 yr b p it evolved through frequent water level fluctuations which reflected the regional hydrological and climatic conditions we determined the water level of the lake for the time interval 55 000 15 000 cal yr b p by mapping offshore nearshore and fan delta sediments by application of sequence stratigraphy methods and by dating with radiocarbon and u series methods during the studied time interval the lake level fluctuated between 340 and 160 m below mean sea level msl between 55 000 and 30 000 cal yr b p the lake evolved through short term fluctuations around 280 290 m below msl punctuated at 48 000 43 000 cal yr b p by a drop event to at least 340 m below msl at 27 000 cal yr b p the lake began to rise sharply reaching its maximum elevation of about 164 m below msl between 26 000 and 23 000 cal yr b p then it began dropping and reached 300 m below msl at 15 000 cal yr b p during the holocene the lake corresponding to the present dead sea stabilized at ca 400 m below msl with minor fluctuations the hypsometric curve of the basin indicates that large changes in lake area are expected at above 403 and 385 m below msl at these elevations the lake level is buffered lake lisan was always higher than 380 m below msl indicating a significantly large water contribution to the basin the long and repetitious periods of stabilization at 280 290 m below msl during lake lisan time indicate hydrological control combined with the existence of a physical sill at this elevation crossing this sill could not have been achieved without a dramatic increase in the total water input to the lake as occurred during the fast and intense lake rise from 280 to 160 m below msl at 27 000 cal yr b p

collapse sinkholes and radar interferometry reveal neotectonics concealed within the dead sea basin 1 the dead sea ds pull apart basin is one of the more seismically active segments of the ds transform plate boundary in the last decade hundreds of collapse sinkholes have been formed along the ds coastlines in israel and jordan causing severe damage to the regional infrastructure the formation of these sinkholes is attributed to the dissolution of a buried salt layer by fresh groundwater due to the drop of the ds and the associated groundwater levels here we show that the sinkhole distribution combined with gradual land subsidence measured by radar interferometry insar track young fault systems suspected as active concealed within the fill of the ds rift this notion is supported by 1 sinkholes clustering along discrete lineaments with a striking trend similarity to that of the exposed rift margin faults 2 prominent discontinuities in seismic reflection profiles offsetting young sediments several kyrs old below sinkhole lines and 3 straight boundaries of gradual subsidence features that coincide with or parallel sinkhole lines combined the sinkhole lineaments and the insar measurements reveal a zigzag pattern of buried faults within the ds rift fill

a 40 000 year unchanging seismic regime in the dead sea rift we studied breccia beds in lacustrine sediments within the active dead sea basin the beds were deformed by m 5 5 earthquakes during the past 60 k y our new analysis considers both the thickness of breccia beds and the lithology of beds directly overlying them in order to identify 11 m 7 earthquakes that originated within the dead sea pull apart between 54 and 16 ka the resulting time series is a unique long record of earthquakes in a well constrained segment of a fault system in which the time interval between consecutive earthquakes increased from hundreds of years to a background recurrence interval of 11 k y since ca 40 ka since this recurrence interval is similar to the m 7 2 recurrence interval in the dead sea basin as extrapolated from present seismicity we suggest that the present seismic regime in the dead sea basin as reflected in its magnitude frequency relation as well as in its deficiency in seismic moment has been stationary for the past 40 k y since the increasing interval between consecutive earthquakes in the studied segment of the dead sea fault is time logarithmic it may be a result of healing of the brittle crust as well as a diminishing strain rate following the first strong earthquake in the sequence

are slump folds reliable indicators of downslope flow in recent mass transport deposits abstract despite the widespread use of slump folds as indicators of palaeoslope orientation there is a lack of detailed analysis of variations in fold geometries and orientations down the length of individual slump profiles within mass transport deposits mtds to address this gap in knowledge we have systematically recorded more than 500 structural measurements of fold hinges and axial planes along a 25 m section through a mesoscopic slump profile our case study is performed in wet unconsolidated late holocene sediments which are only recently exposed due to falling water levels in the dead sea in this situation the modern slope is exposed and directly visible slumping having occurred in the past few centuries fold hinges define broad arcs at high angles to flow in the downslope toe of the slump and progressively swing to become sub parallel to flow in the upslope region greatest amounts of shortening 35 are recorded at the toe suggesting that the swing in trends of fold hinges and axial planes is a consequence of differential layer normal shear rather than downslope strain gradients significant variations of 90 occur in the orientation and vergence of slump folds on either side of a 10 m wide gully which cuts the slump sheet in some instances folds have nucleated around longer 10 cm wooden sticks that were incorporated into the slump whereas shorter wooden fragments align parallel to the flow direction the differences in orientations of wooden sticks and wooden fragments are consistent with differential layer normal shear on each side of a flow cell evaporite concretions grew within the sediments during slumping and influenced the geometry and kinematics of slump folds suggesting that slope failure may have been a slow creep event generated by slope instability rather than a result of catastrophic failure associated with large earthquakes our work illustrates the problems associated with using partial datasets where classical structural analysis of transects

palaeolimnology of lake sapanca and identification of historic earthquake signals northern anatolian fault zone turkey abstract lake sapanca is located on a strand of the northern anatolian fault zone nafz turkey where a series of strong earthquakes ms 6 0 have occurred over the past hundred years identifying prehistoric earthquakes in and around lake sapanca is key to a better understanding of plate movements along the nafz this study contributes to the development of palaeolimnological tools to identify past earthquakes in lake sapanca to this end several promising proxies were investigated specifically lithology magnetic susceptibility grain size thin section and laser analysis geochemistry pollen concentration diatom assemblages 137cs and 210pb sedimentological indicators provided evidence for reworked turbidite like or homogeneous facies event layers in several short cores

distribution of holocene sediments and neotectonics in the deep north basin of the dead sea abstract the distribution of holocene sediments and active faults in the central portion of the northern dead sea basin was analyzed from high resolution seismic reflection data the seismic reflection profiles reveal that sediments buried at a shallow depth are flat lying continuous and unfaulted within the central basin floor four prominent subsurface seismic reflectors were identified that based on limited core data represent the contact between rock salt and marl layers isopach and structural maps of recent sediments indicate an asymmetry of active subsidence with thick accumulations located closer to the east margin of the basin sediment thickness increases within a rhomb shaped depression whose long axis is oriented approximately 20 30 counterclockwise to the regional basin bounding faults the morphology and trend of the locus of maximum subsidence suggests tectonic control of the depression however the proximity of the depocenter of recent sediments to the ein gedi diapir and rim depression suggests that local sub basinal subsidence may also be related to movement of rock salt at depth the basinal strata are deformed along the faults that form a bathymetric escarpment along the west east and south margins of the north basin of the dead sea thinning of recent sediments toward the faults indicates syntectonic deposition

long term earthquake clustering a 50 000 year paleoseismic record in the dead sea graben the temporal distribution of earthquakes in the dead sea graben is studied through a 50 000 year paleoseismic record recovered in laminated sediments of the late pleistocene lake lisan paleo dead sea the lisan represents more than 10 times the 4000 years of historical earthquake records it is the longest and most complete paleoseismic record along the dead sea transform and possibly the longest continuous record on earth it includes unique exposures of seismite beds earthquake induced structures associated with slip events on syndepositional faults the seismites are layers consisting of mixtures of fragmented and pulverized laminae the places where the seismites abut syndepositional faults are interpreted as evidence for their formation at the sediment water interface during slip events on these faults thicker sediment accumulation above the seismites in the downthrown blocks indicates that a seismite formed at the water sediment interface on both sides of the fault scarps modern analogs and the association with surface ruptures suggest that each seismite formed during a m l 5 5 earthquake the 230 th 234 u ages of a columnar section obtained by thermal ionization mass spectrometry give a mean recurrence time of 1600 years of m l 5 5 earthquakes in the dead sea graben the earthquakes cluster in 10 000 year periods separated by quiet periods of similar length this distribution implies that a long term behavior of the dead sea transform should be represented by a mean recurrence of at least 20 000 year record this observation has ramifications for seismic hazard assessment based on shorter records

geochemistry of the lisan and damya formations in jordan and implications for palaeoclimate abstract geochemical mineralogical and sedimentological investigations carried out on the lacustrine lisan and damya formations of the jordan rift valley reveal three major and several minor transgressive depositional cycles all terminating with massive gypsum precipitation the highest level of lake lisan is reported in the literature at 130 m below mean sea level b s l from 70 45 calibrated ka bp the lisan formation is characterised by a high gypsum aragonite ratio and a low lithogenic content implying a regression of an initially high water level caused by reduced water input in the following interval ca 45 36 cal ka bp two low water stands are marked by higher salt concentrations after recovery and a period of higher water level the lake lisan era ends with a strong regression at around 16 cal ka bp this date coincides with the period when lake van eastern turkey also fell dry thus marking a strong drought signal in the entire near east the overlying damya formation containing more lithogenics records lake level fluctuations at around 300 m b s l the existence of a north south precipitation gradient as present today is indicated by increasing sr ca ratios in aragonite and a decreasing lithogenic content in a n s direction secondary gypsum formed diagenetically and aragonite and low mg calcite was transformed into high mg fe calcite

reevaluation of the lake sediment chronology in the dead sea basin israel based on new 230th u dates the dead sea is surrounded by chemical and detrital sediments that were deposited in its larger precursor lakes lake samra and lake lisan the sedimentary history of these lakes was recon structed by means of 230th234u ages of 30 samples mostly of argonite laminae from 8 columnar sections up to 110 km apart the general validity of the ages was demonstrated by subjecting them to tests of internal isotopic consistency agreement with stratigraphic order and concordance with 14c ages in the south only the part of the samra formation older than 170 000 yr is exposed while the aragonite detritus rhythmites found in the central and northern region are generally younger than 120 000 yr the lisan formation started accumulating about 63 000 yr b p with the clay and aragonite beds in the south central area reflecting a rise in water level to at least 280 m the upper part of the lisan formation the aragonite rich white cliff member started accumulating about 36 000 yr b p the lake probably reached its highest level sometime after this based on the ages of lisan sediments preserved in the southernmost reaches of the basin

apatite and monazite an effective duo to unravel superimposed fluid flow and deformation events in reactivated shear zones abstract mylonitic shear zones crosscutting homogenous granitoids can retain evidence of fluid driven metasomatic retrogression and reactivation however the relationships between fluid rock interaction retrogression deformation and mylonitisation and the timing thereof are often cryptically recorded this study focuses on the granulite facies boothby orthogneiss from the reynolds range central australia which contains a large scale mylonitic shear zone with an apparent record of structural inheritance fluid infiltration and reactivation the chosen site provides an ideal natural laboratory in which to investigate the timing of deformation associated fluid flow and mass transport u pb isotope analyses of monazite indicate an average pb recrystallization age of c 1560 ma demonstrating that the orthogneiss fabric developed during the mesoproterozoic chewings orogeny 1590 1550 ma structural mapping suggests that this shear zone represents a riedel branch of larger structures that were subsequently reactivated during the paleozoic alice springs orogeny 450 300 ma the timing of reactivation and fluid flow is constrained by u pb dating of apatite which is present as a stable u bearing mineral in both orthogneiss and mylonite modelling of apatite radiogenic pb retention ages accounting for a wide potential range in common pb compositions demonstrates at least some growth and or recrystallization at c 1500 ma and c 400 ma confirming apatite precipitation during alice springs shearing and the reactivation of chewings age structures in addition alice springs aged apatite is found along pre existing fabrics in the orthogneiss in the vicinity of the shear zone indicating pre kinematic fluid flow across the shear zone boundary and into country rock that was otherwise largely unaffected the combined datasets demonstrates that integrated apatite and monazite u pb geochronology is an effective method to unravel the record of superimposed fluid flow and deformation events this includes the detection of an inverse younging relationship where younger ages are preferentially recorded in the wall rock as rather than in the reactivated shear zone such effects are potentially common where deformation is driven by pre kinematic fluid rock interaction with subsequent deformation enhancing the removal of replacement assemblages in more deformed rocks and favouring their preservation in less deformed rocks

tsunami and seiche triggered deformation within offshore sediments abstract most studies of tsunami and seiche related deposits have focussed on coastal and near coastal zones which are most readily accessible with few investigations of deeper water settings and the potential soft sediment deformation effects of such waves the late pleistocene lisan formation outcropping to the west of the dead sea contains superb examples of sedimentary slump folds formed in water depths of

abrupt aridities and salt deposition in the post glacial dead sea and their north atlantic connection abstract abrupt arid events in the post glacial 17 4 10 kyr bp dead sea basin dsb were recorded by significant lake level declines in lake lisan and massive deposition of gypsum and salt between 17 4 and 16 kyr cal bp the lake level dropped from its late mis2 stand of 260 m below mean sea level m bmsl to 330 m bmsl depositing a thick sequence of gypsum between 16 and 15 kyr cal bp the lake level recovered but dropped abruptly again at 14 kyr cal bp to below 465 m bmsl probably the lowest late pleistocene stand then between 13 and 11 kyr cal bp the younger dryas time interval the lake rose above 400 m bmsl and declined at 11 10 kyr cal bp depositing a thick sequence of salt the abrupt lake level drops and salt deposition coincided with times of ice and meltwater discharges into the north atlantic na heinrich event h1 and meltwater pulse mwp1a similar coincidence between ice and meltwater discharges in the na e g h events and arid episodes at the levant was recorded during the colder last glacial period demonstrating a persistent effect of the north atlantic hydrology and sea ice advances on the levant climate the climatically turmoil post glacial period was accompanied by significant developments in human culture the collapse of the natufian culture during the bolling allerod and the rise of the pre pottery neolithic cultures ppn a and b around the 11 10 kyr cal bp salt deposition interval marking the initiation of the neolithic revolution in the region

the holocene climatic record of the salt caves of mount sedom israel mount sedom is a salt diapir on the southwestern shore of the dead sea which has been rising above the local base level throughout the holocene karst development within the salt body has kept pace with the rise forming subhorizontal cave passages with vertical shafts wood fragments found embedded in flood sediments that were deposited in the cave passages yielded 14c ages ranging from c 7100 to 200 bp a palaeoclimatic sequence was constructed based on parameters that include relative abundance of plant types or floral communities the elevations of the corresponding cave passages and the ratio of their width to present passage width the results were correlated to the holocene sedimentary sequence of the dead sea basin and other features associated with shifting lake levels moister climatic stages are indicated by relatively abundant wood remains by wide cave passages and by elevated outlets indicating high dead sea level arid periods are marked by a scarcity of wood remains by narrow cave pa

recognition of earthquake related damage in archaeological sites examples from the dead sea fault zone abstract archaeological structures that exhibit seismogenic damage expand our knowledge of temporal and spatial distribution of earthquakes afford independent examination of historical accounts provide information on local earthquake intensities and enable the delineation of macroseismic zones they also illustrate what might happen in future earthquakes in order to recover this information we should be able to distinguish earthquake damage from anthropogenic damage and from other natural processes of wear and tear the present paper reviews several types of damage that can be attributed with high certainty to earthquakes and discusses associated caveats in the rare cases where faults intersect with archaeological sites offset structures enable precise determination of sense and size of slip and constrain its time among the characteristic off fault damage types i consider horizontal shifting of large building blocks downward sliding of one or several blocks from masonry arches collapse of heavy stably built walls chipping of corners of building blocks and aligned falling of walls and columns other damage features are less conclusive and require additional evidence e g fractures that cut across several structures leaning walls and columns warps and bulges in walls circumstantial evidence for catastrophic earthquake related destruction includes contemporaneous damage in many sites in the same area absence of weapons or other anthropogenic damage stratigraphic data on collapse of walls and ceilings onto floors and other living horizons and burial of valuable artifacts as well as associated geological palaeoseismic phenomena such as liquefaction land and rock slides and fault ruptures additional support may be found in reliable historical accounts special care must be taken in order to avoid circular reasoning by maintaining the independence of data acquisition methods

earthquake damage history in israel and its close surrounding evaluation of spatial and temporal patterns abstract israel was hit by destructive earthquakes many times in the course of history to properly understand the hazard and support effective preparedness towards future earthquakes we examined the spatial and temporal distribution of the resulted damage we described in detail our systematic approach to searching the available literature collecting the data and screening the authenticity of that information we used gis geographic information system to map and evaluate the distribution of the damage and to search for recurring patterns overall it is found that 186 localities were hit 54 of them at least twice we also found that israel was affected by 4 17 8 and 2 damaging earthquakes that originated respectively from the southern central central northern and northern parts of the dead sea transform dst the temporal appearance of the northern earthquakes is clustered the central earthquakes are more regular in time whereas no damage from the north central and the central quakes with the exception of the year 363 earthquake seems to have occurred south of the dead sea region analyzing the distribution of the damage we realized that the number of the damage reports reflects only half of the incidents that actually happened attesting to incompleteness of the historical catalogue jerusalem is the most reported city with 14 entries followed by akko acre tiberias nablus and tyre with 8 7 7 and 6 reports respectively in general localities in the galilee and north of it suffered more severely than localities in central israel with the exception of nablus and the localities along the coastal plain of israel most probably due to local site effects for the sake of hazard management these observations should be considered for future planning and risk mitigation

rock magnetism of greigite bearing sediments from the dead sea israel summary detailed magnetostratigraphic investigations were carried out on five sediment cores obtained from three sites on the northwestern shore of the dead sea israel the sediments are heterogeneous composed of fine clastic layers alternating with authigenic aragonite the magnetic remanence is carried by ti magnetite and greigite reflecting a detrital as well as an authigenic phase directions of the characteristic remanent magnetization were obtained from stepwise af demagnetization of the natural remanent magnetization and subsequent principle component analysis the acquisition of a gyroremanent magnetization in a noticeable amount of the samples could be linked to core disturbances the depth age models based on ams 14c datings on plant remains yielded an age of 10 04 ka cal bp for the base of the longest profile from site ein gedi a continuous lacustrine sediment sequence the profiles from the two other sites representing near shore sedimentation are interrupted by a hiatus in sedimentation comparison of the inclination and declination records from all dead sea cores and nearby sited lakes suggest that low frequency variations documented in the dead sea sediments are likely of geomagnetic origin

recurrence pattern of holocene earthquakes along the dead sea transform revealed by varve counting and radiocarbon dating of lacustrine sediments abstract a high resolution holocene seismic history of the dead sea transform dst is established from laminated sedimentary cores recovered at the shores of the dead sea radiocarbon dating and annual laminae counting yield excellent agreement between disturbed sedimentary structures identified as seismites and the historical earthquake record all recent and historical strong events of the area were identified including the major earthquakes of a d 1927 1837 1212 1033 749 and 31 b c the total of 53 seismites recognized along the entire holocene profile indicate varying recurrence intervals of seismic activity between a few and 1000 years with a conspicuous minimum rate at 2100 31 b c and a noticeable maximum during the past six to eight centuries most of the epicenters of the correlated earthquakes are situated very close to the dead sea within 150 km or up to 400 km north of it along the dst between 1000 b c and a d 1063 and from a d 1600 to recent time the epicenters are all located on the northern segment of the dst whereas prior to 1000 b c and between a d 1000 and 1600 they appear to scatter along several segments of the dst we establish how the local intensity exerts a control on the formation of seismites at historically estimated intensities greater than vii all well documented earthquakes are correlated whereas at intensities smaller than vi none are matching the periods with enhanced earthquake rate along the dst correlate with those along the north anatolian fault as opposed to the intervening east anatolian fault this may indicate some elastic coupling on plate boundary scale that may also underlie escape and extrusion tectonics typical of continental collision

provenance and earthquake signature of the last deglacial xinmocun lacustrine sediments at diexi east tibet abstract well preserved lacustrine sediments are found in some areas in east tibet this region is characterized by a windy and semi arid climate alpine valleys and frequent earthquakes measurements of rare earth elements observations from a scanning electron microscope and a high resolution record of grain size measurements allowed us to compare fine sediments from the xinmocun section in the diexi lake with loess from the chinese loess plateau and south china results indicate that fine grains of the xinmocun lacustrine sediments were transported by wind and trapped in the lake whereas the 16 m fraction was likely from local sources the grain size changes within the section repeatedly show abrupt coarsening and upward fining probably due to palaeoearthquake events large earthquakes in the study area often caused rockfalls and landslides exposing fine sediments that had accumulated on mountains slopes the fine grains were then retransported by wind to the diexi lake optically stimulated luminescence dating of the xinmocun section indicates continuous deposition from 18 65 to 10 63 ka these results indicate that palaeoearthquakes in the study area had a mean recurrence interval of 0 32 ka therefore we propose that lacustrine sediments in a tectonically active region have the potential to record a continuous history of palaeoearthquakes palaeoearthquakes probably produced numerous rockfalls and landslides in alpine valleys and provided significant sources of regional eolian dust

dating large infrequent earthquakes by damaged cave deposits the long term recurrence patterns of past earthquakes are of considerable consequence for hazard assessments and have implications for earthquake physics we introduce a rigorously dated record of earthquakes from an extensive number of well preserved pre seismic and postseismic precipitates from caves located off the dead sea transform we dated events directly at the paleoseismic contact by means of a novel correlation method with the oxygen isotope record of the speleothems recovered in one of the caves within the 185 k y covered we dated 38 seismite samples these stem from 13 18 earthquakes with a mean recurrence interval of 10 14 k y we show that the deformational events dated in the study caves complement independent near fault paleoseismic records by tem poral correlation with the earthquakes recorded therein this opens up a significant new avenue of earthquake research that will provide precise dating and observational con straints on large infrequent earthquakes

surface ruptures induced by the devastating 1068 ad earthquake in the southern arava valley dead sea rift israel abstract the elat fault a segment of the dead sea transform runs along the southern arava valley part of the dead sea rift israel forming a complex fault zone that displays a time dependent seismic behaviour paleoseismic evidence shows that this fault zone has generated at least 15 earthquakes of magnitude larger than m 6 during the late pleistocene and the holocene however at present the elat fault is one of the quietest segments of the dead sea transform lacking even microsesimicity the last event detected in the southern arava valley occurred in the avrona playa and was strong enough to have deformed the playa and to change it from a closed basin with internal drainage into an open basin draining to the south paleoseismological geophysical and archaeological evidences indicate that this event was the historical devastating earthquake which occurred in 1068 ad in the eastern mediterranean region according to the present study this event was strong enough to rupture the surface reactivate at least two fault branches of the elat fault and vertically displace the surface and an early islamic irrigation system by at least 1 m in addition the playa area was uplifted between 2 5 and 3 m along the eastern part of the elat fault shear zone such values are compatible with an earthquake magnitude ranging between m 6 6 and 7 since the average recurrence interval of strong earthquakes during the holocene along the elat fault is about 1 2 0 3 ky and the last earthquake occurred more about 1000 years ago the possibility of a very strong earthquake in this area in the future should be seriously considered in assessing seismic hazards

holocene seismic and tectonic activity in the dead sea area abstract 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