seismic study of pull apart induced sedimentation and deformation in the northern gulf of aqaba elat abstract new multichannel seismic and bathymetric data are presented which clarify the plio quaternary evolution of the northern gulf of aqaba elat and the dead sea transform dst the seismic data reveal two main seismic sequences a lower pretectonic and an upper syntectonic unit separated by a prominent unconformity these units are each linked to a distinct tectonic phase in the history of the dst parallel horizons and an undisturbed internal structure point to a tectonic quite time or pure strike slip without extension or compression during the first pretectonic phase the second syntectonic phase which begins in the early pliocene is characterized by a major change in the activity of the dst the pretectonic sedimentary unit subsided and consequently dips southward with a supplementary inclination to the east the coeval sedimentation of the syntectonic unit is recorded by the divergent reflection pattern and onlap terminations on the unconformity the apparent fault system seems to be rearranged in the second phase the stepover of the main strand of the dst from the eastern side of the elat deep to the western side of the northern gulf of aqaba was mapped in detail for the first time the very smooth shape of the stepover and the apparent lack of extensional tectonics do not fit with the classical pull apart basin model for the elat deep and point to a decoupling of the crystalline basement from the sedimentary overburden comparisons of the new geophysical findings with analog models support this assertion

ekman transport along the galician coast northwest spain calculated from forecasted winds 1 ekman transport is studied close to the galician coast by means of forecasted winds provided by meteogalicia from november 2001 to october 2004 three different coastal zones are identified western coast from mino river to cape finisterre middle coast from cape finisterre to cape ortegal and northern coast from cape ortegal to cape penas in addition to existence of long term variations the periodicity of the transport signal is characterized by an annual component 365 days a seasonal fluctuation 50 to 80 days and a timescale related to passing storms 15 20 days although the periodicity of the signal is similar at the three zones owing to external meteorological forcing the ekman transport is modulated by the presence of the coast in such a way that seasonal patterns vary in intensity and direction along the coast thus the autumn winter pattern is characterized by high transport at the northern and middle coast pointing landward perpendicular to the shoreline and moderate values at the western coast pointing landward and oblique to the shoreline on the other hand the spring summer pattern is characterized by high transport at the western coast pointing seaward perpendicular to the shoreline the same orientation is observed at the middle coast although with a lower magnitude finally ekman transport at the northern coast points landward and oblique to the shoreline the different transport orientations are shown to be responsible for the upwelling probability variation along the coast

palaeoceanography tropical ties changes in dust flux export productivity and bottom water oxygenation in the equatorial pacific ocean have been tightly linked with variations in north atlantic climate over the past 100 000 years according to analyses of marine sediments

sedimentary and tectonic features in the northwestern gulf of elat israel abstract sedimentary phenomena and tectonic features in the northern gulf of elat were studied at water depths of 50 to 300 m the study includes bathymetric mapping to a depth of 300 m and diving with a small submersible to 215 m the bathymetric map displays two sedimentary terraces at depths of 50 to 90 m and 120 to 140 m a few submarine canyons a large fault called here the elat fault and several small faults and slides the dives with the submersible reveal the nature of the sedimentary cover and the character of the sedimentary terraces they also permit direct observations of fossil reefs submarine canyons the elat fault and other small fractures and faults we suggest that the sedimentary terraces represent late pleistocene sea level stands the 50 to 90 m deep terrace probably was formed during stage 3 of the isotopic curve of shackelton and opdyke about 50 000 to 70 000 years b p whereas the fossil reef at 120 to 140 m depth is correlated with the climax of the last glacial period about 18 000 years b p the submarine canyons and deltas also developed during the last glacial period the elat fault has been active after the development of the 50 to 90 m depth terrace and probably displaced in a left lateral movement some submarine features by 600 to 800 m

the seismicity along the dead sea fault during the last 60 000 years abstract evidence for unchanging slip rate and a gutenberg richter relation for earthquake distribution along the dead sea fault during the past 60 000 yr are presented the evidence comes from three different segments approximately 100 km apart and from three different timescales prehistoric paleoseismic historical and modern instrumental records the paleoseismic data are based on two different methods in the southern arava valley and the northern jordan valley segments the amount of normal displacement along several faults is used while in the dead sea basin the appearance of brecciated beds which are considered as seismites is used we found that for the southern arava valley segment a constant dip slip rate of 0 5 mm yr can explain the cumulative normal slip during the past 45 000 yr this suggests that normal faulting is only 10 of the total left lateral strike slip motion we also found that for all three segments the paleoseismic and historical records of strong earthquakes lie on the linear extrapolation of the frequency magnitude relation of the instrumental record the calculated b values for all three segments are between 0 85 and 1 similar to other major strike slip faults in the world it is concluded that the gutenberg richter distribution is a stable mode in the tectonic setting of the dead sea fault during the past 60 000 yr

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

s wave velocity images of the dead sea basin provided by ambient seismic noise abstract based on passive seismic interferometry applied to ambient seismic noise recordings between station pairs belonging to a small scale array we have obtained shear wave velocity images of the uppermost materials that make up the dead sea basin we extracted empirical green s functions from cross correlations of long term recordings of continuous data and measured inter station rayleigh wave group velocities from the daily correlation functions for positive and negative correlation time lags in the 0 1 0 5 hz bandwidth a tomographic inversion of the travel times estimated for each frequency is performed allowing the laterally varying 3 d surface wave velocity structure below the array to be retrieved subsequently the velocity frequency curves are inverted to obtain s wave velocity images of the study area as horizontal depth sections and longitude and latitude depth sections the results which are consistent with other previous ones provide clear images of the local seismic velocity structure of the basin low shear velocities are dominant at shallow depths above 3 5 km but even so a spit of land with a depth that does not exceed 4 km is identified as a salt diapir separating the low velocities associated with sedimentary infill on both sides of the lisan peninsula the lack of low speeds at the sampling depth of 11 5 km implies that there are no sediments and therefore that the basement is near 10 11 km depth but gradually decreasing from south to north the results also highlight the bowl shaped basin with poorly consolidated sedimentary materials accumulated in the central part of the basin the structure of the western margin of the basin evidences a certain asymmetry both whether it is compared to the eastern margin and it is observed in north south direction infill materials down to 8 km depth are observed in the hollow of the basin unlike what happens in the north and south where they are spread beyond the western dead sea shore

structural framework of the gulf of elat aqaba northern red sea the gulf of elat aqaba occupies the southern part of the dead sea rift the rift is considered to be a plate boundary of the transform type partially leaky which connects seafloor spreading in the red sea with the sagros taurus zone of continental collision the deep water in the gulf of elat up to 1850 m provides a rare opportunity to examine the process of continental rifting by marine geophysical techniques the bathymetry alone provides much information about fault patterns in this area the fragmentation of the once continuous arabian african platform is a complicated process it shapes the structure of the gulf which has developed through continuing tectonism primarily consisting of faulting recent geophysical and geological studies of the gulf of elat including bathymetry bottom photographs continuous seismic profiles seismic refraction gravity magnetics heat flow and coring provide new information about the shallow and deep crustal structure of this important segment of the world rift system the shallow structure of the gulf is dominated by three elongated en echelon basins which strike n20 25 e undulations in the floors of the basins produce several distinct deeps these basins are interpreted as pullaparts the new data from the gulf suggest that classical models for the formation of these structures should be modified only one of the longitudinal faults of each depression is a strike slip fault while the other is predominantly a normal fault the situation with the other two sides of the basin which are supposed to be composed of normal faults may also be more complex than previously thought at least in one case one such boundary is composed of a strike slip fault while the other has no significant fault crustal models of the gulf of elat based on gravity data indicate that the basins are rather shallow and do not extend into the lower crust the fill of the basins extends to about 5 km below the seafloor in the northern and southern basins and less in the central basin most significant magnetic anomalies in the gulf of elat extend from land into the sea none of them however extends from one coast to another across the gulf this supports the geological evidence for a shear between the arabia and sinai plates the magnetic field over the southern third of the gulf is rather smooth and markedly different from that of the other parts the nature of the magnetics the crustal structure of the western margin and the heat flow values indicate a thinner crust and different tectonic processes in the southern part of the gulf overall it seems that within the southern gulf of elat a transition occurs between crustal spreading that takes place in the red sea to a rifting without spreading that takes place along the dead sea transform spreading activity propagates from south to north the most active place is the central basin which is being propagated northward into the shallow northern basin

compiling an earthquake catalogue for the arabian plate western asia abstract the arabian plate is surrounded by regions of relatively high seismicity accounting for this seismicity is of great importance for seismic hazard and risk assessments seismic zoning and land use in this study a homogenous earthquake catalogue of moment magnitude mw for the arabian plate is provided the comprehensive and homogenous earthquake catalogue provided in the current study spatially involves the entire arabian peninsula and neighboring areas covering all earthquake sources that can generate substantial hazard for the arabian plate mainland the catalogue extends in time from 19 to 2015 with a total number of 13 156 events of which 497 are historical events four polygons covering the entire arabian plate were delineated and different data sources including special studies local regional and international catalogues were used to prepare the earthquake catalogue moment magnitudes mw that provided by original sources were given the highest magnitude type priority and introduced to the catalogues with their references earthquakes with magnitude differ from mw were converted into this scale applying empirical relationships derived in the current or in previous studies the four polygons catalogues were included in two comprehensive earthquake catalogues constituting the historical and instrumental periods duplicate events were identified and discarded from the current catalogue the present earthquake catalogue was declustered in order to contain only independent events and investigated for the completeness with time of different magnitude spans

the somalia plate and the east african rift system present day kinematics summary the motion of the somalia plate relative to the nubia africa arabia and antarctica platcs is re evaluated using a new inversion method based on a monte carlo technique and a least absolute value misfit criterion a subset of the nuvel 1 data set with additional data along the levant fault and in the red sea is used the results confirm that the motion of arabia with respect to africa is significantly different from the motion relative to somalia it is further shown that the data along the sw indian ridge are compatible with a pole of relative motion between africa and somalia located close to the hypothetical diffuse triple junction between the ridge and thc east african rift the resulting africa somalia motion is then compatible with the geological structures and seismological data along the east african rift system assuming a separate somalia plate thus solves kinematic and geological problems around the afar triple junction and along the east african rift

new aspects of rhomb structures abstract the acute angles of 48 rhombic trapezoidal and triangular grabens horsts and upthrusts throughout the world were determined the results indicate an angular spread of 7 73 in most structures the two acute angles differ considerably most rhomb structures are grabens which show affinities to seismic faults and only a few are horsts and upthrusts in this connection modes of static crustal fracture propagation are compared to dynamic propagation rhomb structures occur along strike slip faults and in rifts these results question the universality of the pull apart model as a mechanism for rhomb structure development the two mechanisms that can lead to the formation of rhomb structures are 1 interaction of en echelon or non coplanar fractures by shear and extensional modes and 2 fracture bifurcation in an extensional mode the two mechanisms may result in faults of different shapes characterized by curved and straight boundaries respectively the grabens and horsts in extensional regions are the consequence of early fracture and later vertical displacements

translocated plio pleistocene drainage systems along the arava fault of the dead sea transform abstract geomorphic and sedimentologic field studies and analyses of landsat 5 images and topographic maps indicate 15 km of left lateral displacement of a pliocene large stream and alluvial fans along the dead sea transform in southern israel and jordan in the central arava valley a rift valley located along the transform there is a notable discrepancy between the number and location of the feeding drainage basins within the eastern margins of the arava valley and those of the alluvial fans and the cross rift large stream a few of these large alluvial fans lack any feeding drainage basin furthermore east of the large stream there is no drainage basin that could have fed it these discrepancies between the physiography locations sizes and lithological compositions of the feeding drainage basins and of the alluvial fans can be explained by 15 km of left lateral movement since the late pliocene or the early pleistocene along the arava dead sea segment of the transform this is one of the largest displacements of a landform and surficial alluvial deposit in the world however the resulting average long term rate of movement is relatively small 0 3 0 75 cm year

active tectonics along the wadi araba jordan valley transform fault a geological study has been carried out along the 200 km long wadi araba following the transform fault that separates the arabian and sinai african plates recent movements along this structure affect upper pleistocene holocene deposits and archaeological sites kinematic indicators show sinistral strike slip and oblique movements in agreement with the relative motion between the two plates other evidence of recent horizontal displacement exists along the jordan valley fault both on the dead sea lake tiberias segment and on the segment north of lake tiberias a minimum horizontal slip rate of 1 cm yr 1 has been estimated for both the southern segment of the wadi araba fault and for the southern jordan river fault the two faults can be roughly subdivided into at least four segments two in the wadi araba 80 km long each one from the dead sea to lake tiberias 130 km and one from lake tiberias to the hula graben 30 km faulting may also occur along shorter subsegments as shown by bends in the wadi araba jordan river fault and by the growth of local compression and extension features instrument recorded seismicity appears to be mainly concentrated along some of these subsegments a comparison between the observed seismic and field determined slip rates across the fault indicates possible strain accumulation during the last 2000 years

a dipole like sst trend in the somalia region during the monsoon season sst trends measured in the somalia region during the southwest monsoon season over the period 1982 2013 have shown the existence of a warming cooling dipole the positive spot with a warming trend on the order of 0 37 c dec 1 is centered around 5 1 n 50 3 e and the negative one with a trend on the order of 0 43 c dec 1 around 11 1 n 52 2 e the migration of the great whirl gw over the last three decades at a speed of 0 3 c dec 1 in longitude and 0 6 c dec 1 in latitude was considered as the possible origin of the sst dipole the displacement of the gw produces changes in the geostrophic currents which in turn generate changes in the amount of advected water from and to coast

satellite measurements reveal persistent small scale features in ocean winds four year averages of 25 kilometer resolution measurements of near surface wind speed and direction over the global ocean from the quikscat satellite radar scatterometer reveal the existence of surprisingly persistent small scale features in the dynamically and thermodynamically important curl and divergence of the wind stress air sea interaction over sea surface temperature fronts throughout the world ocean is evident in both the curl and divergence fields as are the influences of islands and coastal mountains ocean currents such as the gulf stream generate distinctive patterns in the curl field these previously unresolved features have important implications for oceanographic and air sea interaction research

climatic warming of atlantic intermediate waters abstract interdecadal temperature variability of the atlantic ocean is investigated by differencing hydrographic sections taken from the 1920s through the 1990s a comprehensive reanalysis of north atlantic sections and the inclusion of south atlantic sections show that warming seen previously in the north atlantic extends to the south atlantic the largest statistically significant changes occur on pressure surfaces between 1000 and 2000 decibars db over this pressure range and for latitudes between 32 s and 36 n temperatures have warmed by 0 5 c century 1 at 48 n a cooling of 3 c century 1 occurred between the 1950s and 1980s these isobaric temperature trends are decomposed into ones along surfaces of constant neutral density and ones due to the vertical movement of neutral surfaces the two components are associated with different processes in the southern north atlantic 8 36 n the subthermocline warming between the 1950s and 1980s appears to be due primarily to downward displacements of n

glacial interglacial co2 change the iron hypothesis several explanations for the 200 to 280 ppm glacial interglacial change in atmospheric co2 concentrations deal with variations in southern ocean phytoplankton productivity and the related use or nonuse of major plant nutrients an hypothesis is presented herein in which arguments are made that new productivity in today s southern ocean 7 4 1013g yr 1 is limited by iron deficiency and hence the phytoplankton are unable to take advantage of the excess surface nitrate phosphate that if used could result in total southern ocean new production of 2 3 1015 g c yr 1 as a consequence of fe limited new productivity holocene interglacial co2 levels preindustrial are as high as they were during the last interglacial 280 ppm in contrast atmospheric dust fe supplies were 50 times higher during the last glacial maximum lgm because of this fe enrichment phytoplankton growth may have been greatly enhanced larger amounts of upwelled nutrients may have been used and the resulting stimulation of new productivity may have contributed to the lgm drawdown of atmospheric co2 to levels of less than 200 ppm background information and arguments in support of this hypothesis are presented

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

earthquake fault superhighways abstract motivated by the observation that the rare earthquakes which propagated for significant distances at supershear speeds occurred on very long straight segments of faults we examine every known major active strike slip fault system on land worldwide and identify those with long 100 km straight portions capable not only of sustained supershear rupture speeds but having the potential to reach compressional wave speeds over significant distances and call them fault superhighways the criteria used for identifying these are discussed these superhighways include portions of the 1000 km long red river fault in china and vietnam passing through hanoi the 1050 km long san andreas fault in california passing close to los angeles santa barbara and san francisco the 1100 km long chaman fault system in pakistan north of karachi the 700 km long sagaing fault connecting the first and second cities of burma rangoon and mandalay the 1600 km great sumatra fault and the 1000 km dead sea fault of the 11 faults so classified nine are in asia and two in north america with seven located near areas of very dense populations based on the current population distribution within 50 km of each fault superhighway we find that more than 60 million people today have increased seismic hazards due to them

the northern edge of the gulf of elat abstract the gulf of elat aqaba is located at the southern portion of the dead sea transform three large sedimentary basins exist within the gulf the northern edge of the gulf of elat the gulf s head forms the divide between the northern sedimentary basin of the gulf the elat deep basin and the on land sedimentary basins of the southern arava valley at this location the gulf of elat narrows considerably a transverse fault zone separates the elat deep basin from the gulf s head this fault zone is highly deformed and consists of numerous distinct faults and subbottom structures several structural elements within this zone extend westward into a graben on the sinai peninsula which is older than the gulf of elat the transverse fault zone connects two large strike slip faults segments of the dead sea transform the southern segment borders the elat deep on the east and the northern segment borders the gulfs head on the west some left lateral displacement is also occurring along the transverse fault zone the transverse fault zone is thus part of the main dead sea transform and not a secondary fault as is found at the southern end of the elat deep it is associated with a magnetic anomaly which is one of the largest recorded in the gulf of elat the existence of such an anomaly possibly indicates basaltic intrusion along this zone other instances where transverse faults extend away from the basinal areas like at the northern boundary of the elat deep can be recognized along the dead sea rift these structures may suggest that the longitudinal dimension of several of the basins is determined during early stages of their formation

the use of acoustic imaging to reveal fossil fluvial systems a case study from the southwestern sea of galilee abstract the analysis of reflected high resolution seismic data shows a distinct separation of regions with good and poor seismic penetration additional analysis of core data revealed good correlation between grain size and seismic penetration as a case study a shallow geophysical survey using a chirp profiler was conducted in the southwestern part of the sea of galilee by correlating the seismic and core data we found that areas with good seismic penetration represent coarse clastics while poor seismic penetration is related to fine clays new detailed bathymetric mapping and bottom morphology images combined with the penetration characteristics of the chirp signal reveal a large alluvial fan consisting mainly of coarse material sand to pebbles a fine grained band of mostly clay size material associated with an asymmetric bathymetric channel continues the trend of the old entrance of the yavniel creek into the sea of galilee we interpret the fine clay stripe to be a low energy streambed of the yavniel creek the clear relations between the reflected chirp signal and the grain size of the water bottom sediments suggests that this type of survey can be used to characterize depositional environments

intense warming and salinity modification of intermediate water masses in the southeastern corner of the bay of biscay for the period 1992 2003 1 the evolution of the intermediate water masses within the southeastern corner of the bay of biscay is studied from the shelf edge and slope stations of a hydrographic standard section northward from santander 43 30 43 54 n 3 47 w the section was sampled monthly from 1991 to autumn 2003 with some gaps more frequent in the early stages due to weather conditions data were systematically collected up to a 1000 m depth or to the maximum depth at the shallower stations showing a detailed picture of the variability in water masses below the mixing layer eastern north atlantic central water has warmed as a consequence of continuous deepening of the isopycnal levels changes in water properties at fixed isopycnal levels are less relevant and highly biased by a 1998 positive peak in temperature and salinity the warming trend found is 0 032 c per year on average on the other hand the mediterranean water has been modified along isopycnals variations 10 times greater than those due to isopycnal displacement increasing progressively both temperature and salinity for the period 1994 2001 the values found are around 0 020 c per year for temperature and 0 005 for salinity as a final picture all water masses below the mixing layer and down to a 1000 m depth in the southern bay of biscay have warmed up during the last decade at rates from two to six times greater than the those accepted for the north atlantic during the last half century

submerged reef terraces in the maldivian archipelago indian ocean abstract sea level changes have shaped the world s carbonate platform margins and continental shelves leaving typical geomorphic imprints such as drowned reef terraces in this paper we present the results of 112 scuba diving transects across seven different maldivian atolls and one multibeam survey around male island the capital of maldives we report on the occurrence of drowned reef terraces down to 120 m depth in total we identified six levels of submerged terraces that we consider as indicative of periods of time with stable or slowly rising sea level that can be attributed either to deceleration of the last deglacial sea level rise or to late quaternary sea level highstands we compare our dataset to the depth of reef terraces reported globally and we discuss the reasons why common global submerged terrace levels are difficult to identify in the field record

stromatolites in caves of the dead sea fault escarpment implications to latest pleistocene lake levels and tectonic subsidence abstract a varied assemblage of algal stromatolites was encountered in caves along the northern section of the dead sea fault escarpment the caves are situated at the lower part of the escarpment at altitudes 310 to 188 m relative to mean sea level m s l i e ca 110 230 m above the present dead sea level the cave stromatolites are mainly composed of aragonite yielding u th ages of 75 17 ka the altitude mineralogy and ages as well as comparison with previously documented stromatolite outcrops in the area ascribe the cave stromatolites to the aragonite precipitating hypersaline lake lisan the late pleistocene predecessor of the dead sea the stromatolites are used as a lake level gauge based on the algae being reliant upon the light of the upper water layer preservation of the original structure and aragonite mineralogy of the stromatolites suggests a closed system regarding the radioactive elements enabling reliable u th dating a curve of lake lisan levels is constructed based on the stromatolite ages and cave elevations the following points are noted 1 lake levels of 247 m relative to m s l are recorded at 75 72 5 ka 2 relatively high lake levels above 220 m relative to m s l are achieved at 41 5 ka and are still recorded at 17 ka 3 the peak level is 188 m relative to m s l at 35 5 29 5 ka these results indicate lake stands up to 80 m higher than previously accepted for large parts of the lake lisan time span this difference is explained by tectonic subsidence of up to 2 2 m ka within the dead sea depression since the latest pleistocene this subsidence rate is in the same order of magnitude with previously calculated subsidence rates for the dead sea depression begin z b zilberman e 1997 main stages and rate of the relief development in israel geological survey of israel report jerusalem unlike previous lake lisan level estimations the new curve is measured at the relatively stable shoulders of the dead sea depression

el nino southern oscillation like variability during glacial terminations and interlatitudinal teleconnections interannual decadal variability in the equatorial pacific el nino southern oscillation enso induces climate changes at global scale but its potential influence during past global climate change is not yet well constrained new high resolution eastern equatorial pacific proxy records of thermocline conditions present new evidence of strong orbital control in enso like variability over the last 275 000 years recurrent intervals of saltier thermocline waters are associated with the dominance of la nina like conditions during glacial terminations coinciding with periods of low precession and high obliquity the parallel dominance of 13c depleted waters supports the advection of antarctic origin waters toward the tropical thermocline this oceanic tunneling is proposed to have reinforced orbitally induced changes in enso like variability composing a complex high and low latitude feedback during glacial terminations

quaternary tectonic evolution of the northern gulf of elat aqaba along the dead sea transform the northern gulf of elat aqaba is located in the transition between the deep marine basins of the gulf and the shallow onland basins of the arava valley interpretation of 500 km of high resolution seismic reflection data collected across the northern shelf reveals the tectonic structure and evolution of this transition six nne trending faults and one e w trending transverse fault are mapped slip rates are calculated based on measured offsets and age determination based on a radiocarbon calibrated sedimentation rate and a quaternary age model the most active fault is the evrona fault that absorbs most of the left lateral slip within the basin with an average sinistral slip rate of 0 7 0 3 mm yr through the late pleistocene and 2 3 3 4 mm yr during the holocene two intrabasin faults east of the evrona fault that have been inactive for the last several tens of thousands of years were mapped and motion from these faults has likely transferred to the evrona fault the basin is flanked on the west by the elat fault and on the east by the aqaba fault both faults are marked by large bathymetric escarpments based on displaced seismic reflectors we calculate a holocene vertical slip rate of 1 0 0 2 and 0 4 0 1 mm yr for the elat and aqaba faults respectively the geometry slip rates and slip history of the northern gulf of elat aqaba faults show that during the late pleistocene several intrabasin faults became dominant across the basin but that during the holocene the evrona fault accommodates most of the strike slip

geological events in the bible the books of the bible contain numerous frequently very exact descriptions of geological events some of these are discussed here earthquakes and their accompanying landslides the crossing of the river jordan seiches and tsunamis the flood flooding sodom and gomorrah faulting burning gas seepages the burning bush and volcanism mount sinai these geological events appear in the biblical text mainly for artistic reasons they serve as a suitable background to dramatize the biblical account they create a supernatural atmosphere for the main stories but the time and place at which they occurred are of no importance to the narrator and might be shifted freely

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

holocene tectonic deformation along the western margins of the dead sea abstract to assess the young tectonic activity along the western margins of the dead sea and north of the lake faults were studied within sediments which are up to 60 000 years old the western margins of the dead sea are dominated by normal step faults which are exposed up to 2 km east of the morphological escarpment of the basin the rate of subsidence accommodated by these normal faults is estimated to be about 0 85 mm y the distribution of the faults suggests that holocene fault activity was most intense in the northwestern corner of the dead sea north of the lake left lateral slip along the jordan fault produced both local compression and extension small reverse faults and folds exposed along this fault indicate a minimum left lateral slip rate of 0 7 mm y

geological structure of the eastern side of the lower jordan valley dead sea rift reflection seismic evidence abstract interpretation of recently released seismic reflection lines from the shuna eastern jericho basin combined with re analysis of the lithologic logs of the deep jv 1 and jv 2 boreholes provide new insights into the structure of the sedimentary basin that formed along the dead sea transform fault north of the dead sea in jordan we identified four major seismic boundaries in the reflection profiles the upper two were correlated with borehole stratigraphy these reflection boundaries include the top of the pan african basement r4 the base of the mesozoic r3 the base of the cretaceous r2 and the base of the post eocene section r1 the latter records sedimentation during the dead sea transform tectonic regime the total thickness attained by the older sedimentary units late cretaceous through cambrian is apparently less than 2 km we identified a subsurface structure a faulted monocline with a n s trend sub parallel to the strike of the dead sea transform that is named here al kharrar monocline the al kharrar structural ensemble is buried by syntectonic lacustrine and fluviatile sediments of the jordan valley group the structure formed as part of the dead sea transform deformation overprinting the late cretaceous syrian arc folds continued tectonic deformation is evident from the prominent unconformity at the base of post eocene syntectonic deposits that dip nw w and s away from the structural high along the nw flank of the al kharrar monocline syntectonic sediment thickness is generally less than 0 5 km while along the sw flank it thickens rapidly to nearly 1 km at the southern end of the interpreted seismic lines this rapid southern subsidence probably continues into the north end of the dead sea basin the lake s shoreline being located less than 3 km to the south young bifurcating faults with reverse slip components cutting the eastern part of the al kharrar monocline are attributed to a positive flower structure this pattern suggests strike slip with localized active compression northeast of the dead sea it may result from local transpression between fault strands that appear to be a northward continuation of the eastern boundary fault of the dead sea basin

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

stress tensor and focal mechanisms along the dead sea fault and related structural elements based on seismological data the dead sea fault is among the largest active strike slip fault of the world this study is focused on the southern part of this fault from the sea of galilee to the gulf of aqaba as monitored mainly by the jordanian and israeli seismic networks the data of arrival times and polarities allowed relocation of earthquakes with a better azimuthal coverage and computation of focal mechanisms this last step has been realized by inverting the polarities to determine a unique stress tensor for the region and the compatible focal mechanisms inversion with different subsets of the data set based on tectonic regionalization has also been performed to evaluate the impact of each cluster of earthquakes on the global solution the population of focal mechanisms is clearly dominated by strike slip events with the notable exception of a cluster of earthquakes south of the dead sea which displays several normal focal mechanisms this last cluster forces 1 to be vertical and 2 to be horizontal a large number of fault planes however are close to the vertical inhibiting the action of the vertical component of the stress tensor and acting like under strike slip stress regime we observed a good agreement between the location of the earthquakes and the active faults based on geological data in addition there is a good agreement between the fault plane solutions and the orientation of the active faults

distinct relict fringing reefs in the northern shelf of the gulf of elat aqaba markers of quaternary eustatic and climatic episodes quaternary reef development and demise have been shown to correspond to worldwide sea level fluctuations and related environmental changes yet the mechanisms and rates affecting this relationship are not well resolved a set of high resolution seismic reflection and multibeam bathymetric data were interpreted six distinct systems of relict fringing reefs embedded within the sedimentary cover of the northern shelf of the gulf of elat aqaba were identified the two uppermost relict fringing reefs are also exposed on the sea floor in water depths of ca 20 m and ca 60 m along the north western corner of the northern gulf of elat aqaba and sub parallel to the current northern coast respectively two other relict fringing reefs are laterally correlated to each of the last two transgressive cycles and are inferred to have formed during decelerations in sea level rise during the last two deglaciations these reefs and the units to which they are laterally correlated portray a repeating stratigraphic pattern of reef development during deposition of seismically homogeneous sediment and an ensuing demise during deposition of heterogeneous sediment correlation of the reef stratigraphy with rates of late quaternary sea level rise and a sediment accumulation rate from one shelf core provide age estimations for the seismic stratigraphy two phases of fringing reef generation occurred during the last deglaciation since ca 18 ka the older reef probably developed between 12 8 ka and 11 5 ka at ca 60 m below present sea level and the younger reef after 8 4 to 8 0 ka at ca 20 m below present sea level these last two phases of reef generation are separated by a lobate seismic unit that is interpreted as fluvial deltaic deposits that backstepped across the shelf during the early holocene transgression results suggest that fringing reefs evolved along the northern shelf of the gulf of elat aqaba only during relative decelerations in sea level rise contemporaneous with low input of terrigenous sediment and probably during a period of aridity at present no fringing reef grows along the northern coast of the gulf of elat aqaba suggesting that these relatively arid periods may have been drier than recent the pattern of slowdown in sea level rise contemporaneous with conditions of increased aridity seems to have repeated during the last two sea level rises approximately at the same sea levels suggesting a common mechanism of short millennium scale phases of eustatic and climatic alteration during deglaciations

desert flash floods form hyperpycnal flows in the coral rich gulf of aqaba red sea abstract running rivers are very scarce in globally distributed hyperarid and arid coastlines 28 000 km worldwide and it is ephemeral rivers that carry most terrestrial sediment into the sea in these regions however there is very little information regarding the contribution of terrestrial sediment and dynamics of transport of sediment that enter marine basins from these rivers one hyperarid region the gulf of aqaba received an exceptional number of flashflood events during the winter of 2012 2013 the results illustrate for the first time how the high volume of flashflood sediment influences the distribution of coral reefs dwarfs the contribution of airborne dust elevates floodwater densities to produce hyperpycnal flows despite highest ocean salinities and is subsequently transported to the deep basin where it may be preserved as a climate archive

glacial interglacial variability in the delivery of dust to the central equatorial pacific ocean abstract fluxes of continental mineral aerosols dust were greater during glacial periods than during interglacials throughout most regions of the earth the equatorial pacific ocean was a possible exception to this pattern in that previous studies have reported either greater dust fluxes during interglacials or no consistent glacial interglacial pattern of dust flux we have applied the 230th normalization technique to derive five new records of dust flux from central equatorial pacific ocean sediments in contrast to previous studies which relied on stratigraphic accumulation rates the 230th normalization technique produces internally consistent results revealing fluxes to this region of continental lithogenic material that were positively correlated with global ice volume throughout the past 300 000 yr maximum glacial fluxes of continental mineral aerosols exceed minimum interglacial fluxes by about a factor of 2 similar to changes found elsewhere at low and mid latitudes this amplitude of variability is substantially smaller than that seen in some recent models and these observations provide a calibration point for future model development

sea level and shoreline reconstructions for the red sea isostatic and tectonic considerations and implications for hominin migration out of africa the history of sea level within the red sea basin impinges on several areas of research for archaeology and prehistory past sea levels of the southern sector define possible pathways of human dispersal out of africa for tectonics the interglacial sea levels provide estimates of rates for vertical tectonics for global sea level studies the red sea sediments contain a significant record of changing water chemistry with implications on the mass exchange between oceans and ice sheets during glacial cycles and because of its geometry and location the red sea provides a test laboratory for models of glacio hydro isostasy the red sea margins contain incomplete records of sea level for the late holocene for the last glacial maximum for the last interglacial and for earlier interglacials these are usually interpreted in terms of tectonics and ocean volume changes but it is shown here that the glacio hydro isostatic process is an additional important component with characteristic spatial variability through an iterative analysis of the holocene and interglacial evidence a separation of the tectonic isostatic and eustatic contributions is possible and we present a predictive model for palaeo shorelines and water depths for a time interval encompassing the period proposed for migrations of modern humans out of africa principal conclusions include the following i late holocene sea level signals evolve along the length of the red sea with characteristic mid holocene highstands not developing in the central part ii last interglacial sea level signals are also location dependent and in the absence of tectonics are not predicted to occur more than 1 2 m above present sea level iii for both periods red sea levels at expected far field elevations are not necessarily indicative of tectonic stability and the evidence points to a long wavelength tectonic uplift component along both the african and arabian northern and central sides of the red sea iv the observational evidence is consistent with tectonic and isostatic processes both operating over the past 300 000 years without requiring changes in the time averaged over a few thousand years tectonic rates v recent bathymetric data for the bab al mandab region have been compiled to confirm the location and depth of the sill controlling flow in and out of the red sea throughout the last 400 000 years the red sea has remained open to the gulf of aden with cross sectional areas at times of glacial maxima about 2 of that today vi the minimum channel widths connecting the red sea to the gulf of aden at times of lowstand occur south of the hanish sill the channels are less than 4 km wide and remain narrow for as long as local sea levels are below 50 m this occurs for a number of sustained periods during the last two glacial cycles and earlier vii periods suitable for crossing between africa and arabia without requiring seaworthy boats or seafaring skills occurred periodically throughout the pleistocene particularly at times of favourable environmental climatic conditions that occurred during times of sea level lowstand

constraints on the magnitude of the deglacial migration of the itcz in the central equatorial pacific ocean abstract accurate paleo latitudinal reconstructions of the intertropical convergence zone itcz are necessary for understanding tropical hydroclimate and atmospheric circulation paleoclimate models and records suggest that as global temperatures increase the itcz should migrate towards the warmer hemisphere many uncertainties remain regarding the magnitude of this migration and few studies have focused on the central equatorial pacific cep here we use eolian dust records recovered from three locations in the cep to address changes in dust provenance across the paleo itcz since the last glacial maximum lgm radiogenic isotope compositions of nd and pb show that dust delivered to the cep was sourced mainly from two regions east asia and south america from these data we deduced that since marine oxygen isotope stage 2 mis2 the itcz has migrated north to its modern position being displaced by as much as 7 to as little as 2 5 we find that the itcz migrated further north during the early holocene 9 kyr reaching its position furthest north during the mid holocene warm interval 7 kyr based on an increase in south american dust at the northernmost sites

relief inversion in the avrona playa as evidence of large magnitude historical earthquakes southern arava valley dead sea rift the arava valley section of the dead sea transform dst in southern israel is characterized by the absence of seismic activity in recent times however paleoseismic analysis of sediments in the avrona playa a pull apart basin along the dst reveals that at least six m 6 tectonic events have affected the avrona playa in the last 14 000 yr the recurrence interval of the events is approximately 2000 yr trenched normal faults and push up ridges in the playa show that the upper 2 m of the deformed sedimentary sequence consists of playa deposits with uniform soil development the deformed sediments and the soil are typical of basins with an endoreic fluvial system based on the limiting age of the sequence and the extent of soil development faulting in the playa followed by compression and uplift occurred in the last 1000 yr this most recent tectonic event displaced the surface by at least 1 m consistent with a m 6 5 earthquake this earthquake changed the morphology of the avrona playa from a closed system with internal drainage to an open basin resulting in relief inversion the seismic quiescence in the arava may indicate a seismic gap in this segment of the dst

mechanical aspects of pull apart basins and push up swells with applications to the dead sea transform abstract pull apart basins and push up swells are common features at steps along strike slip faults the structure of these features is examined here for two types of rheology perfect brittle and perfect ductile the stress fields derived for the step area predict that fault patterns mode of deformation and vertical displacement are different for the two rheologies these predictions are illustrated for basins and swells developed in laboratory experiments with modelling materials the structure of basins and swells along the dead sea transform is discussed here the pull apart basins display an intensively faulted southern end and a gently dipping flexure at the northern end a consistent dissimilarity appears between the structures of the eastern and western boundary faults of the basins according to the present interpretation these dissimilarities reflect a relatively ductile crust in arabia and a relatively brittle crust in sinai israel

three dimensional elastic earthquake modelling based on integrated seismological and insar data the mw 7 2 nuweiba earthquake gulf of elat aqaba 1995 november summary the nuweiba earthquake 1995 november 22 m w 7 2 the largest seismic event along the dead sea transform dst in at least 160 yr ruptured 45 50 km along the aragonese segment of the left stepping strike slip fault system occupying the gulf of elat aqaba southern segment of the dst the rupture initiated in a partly normal low slip first subevent near the southern end of the fault and propagated unilaterally north northeastward as a high slip nearly pure sinistral second subevent which was responsible for over 90 per cent of the total seismic moment the source mechanism and slip distribution derived from inversion of teleseismic broad band waveforms are used to construct a 3 d elastic model of the earthquake based on the boundary elements method resulting in the full 3 d displacement and stress fields induced by the earthquake in the absence of sufficient global positioning system data the only other constraints on the geometry and slip distribution of the rupture are provided by interferometric synthetic aperture radar insar measurements spanning the coseismic and early post seismic period we calculate simulated interferograms by transforming the calculated surface displacement field into the satellite coordinate system and comparing them with the observed interferograms the model parameters are then iteratively modified until a best fitting model is obtained providing a refined set of static source parameters for the mainshock this model is then used to calculate the static coulomb stress changes induced by the mainshock on the step over faults suggesting that the major m w 5 aftershocks in the first eight post seismic months were triggered by small changes 1 bar in the left lateral coulomb stress with effective friction coefficient not higher than 0 2 aftershock distribution and mechanisms indicate that the available coulomb stress dropped below the frictional strength of the fault but was not complete

processes controlling the mean tropical pacific precipitation pattern part i the andes and the eastern pacific itcz abstract the question of why the intertropical convergence zone itcz is generally north of the equator in the tropical pacific is addressed experiments with an atmospheric general circulation model coupled to idealized representations of the ocean show that the presence of the andes is enough to lower sea surface temperature sst off the west coast of south america through evaporation thus promoting a north south asymmetry with the itcz north of the equator which is amplified by interactions between the ocean and the atmosphere the evaporative cooling results mainly from the subsidence of low specific humidity air which is due in turn to the mechanical effect of the andes on the zonal mean flow the positive feedback from low level clouds on sst is an important factor for the efficiency of the mechanism described west of 120 w the presence of the rockies and himalayas produces a comparable forcing to that of the andes but this is not enough to reverse or neutralize the north south asymmetry se

magnetic character of a large continental transform an aeromagnetic survey of the dead sea fault new high resolution airborne magnetic hram data along a 120 km long section of the dead sea transform in southern jordan and israel shed light on the shallow structure of the fault zone and on the kinematics of the plate boundary despite infrequent seismic activity and only intermittent surface exposure the fault is delineated clearly on a map of the first vertical derivative of the magnetic intensity indicating that the source of the magnetic anomaly is shallow the fault is manifested by a 10 20 nt negative anomaly in areas where the fault cuts through magnetic basement and by a 5 nt positive anomaly in other areas modeling suggests that the shallow fault is several hundred meters wide in agreement with other geophysical and geological observations a magnetic expression is observed only along the active trace of the fault and may reflect alteration of magnetic minerals due to fault zone processes or groundwater flow the general lack of surface expression of the fault may reflect the absence of surface rupture during earthquakes the magnetic data also indicate that unlike the san andreas fault the location of this part of the plate boundary was stable throughout its history magnetic anomalies also support a total left lateral offset of 105 110 km along the plate boundary as suggested by others finally despite previous suggestions of transtensional motion along the dead sea transform we did not identify any igneous intrusions related to the activity of this fault segment

tectonic evolution of the qumran basin from high resolution 3 5 khz seismic profiles and its implication for the evolution of the northern dead sea basin abstract the dead sea basin is a morphotectonic depression along the dead sea transform its structure can be described as a deep rhomb graben pull apart flanked by two block faulted marginal zones we have studied the recent tectonic structure of the northwestern margin of the dead sea basin in the area where the northern strike slip master fault enters the basin and approaches the western marginal zone western boundary fault for this purpose we have analyzed 3 5 khz seismic reflection profiles obtained from the northwestern corner of the dead sea the seismic profiles give insight into the recent tectonic deformation of the northwestern margin of the dead sea basin a series of 11 seismic profiles are presented and described although several deformation features can be explained in terms of gravity tectonics it is suggested that the occurrence of strike slip in this part of the dead sea basin is most likely seismic sections reveal a narrow zone of intensely deformed strata this zone gradually merges into a zone marked by a newly discovered tectonic depression the qumran basin it is speculated that both structural zones originate from strike slip along right bending faults that splay off from the jordan fault the strike slip master fault that delimits the active dead sea rhomb graben on the west fault interaction between the strike slip master fault and the normal faults bounding the transform valley seems the most plausible explanation for the origin of the right bending splays we suggest that the observed southward widening of the dead sea basin possibly results from the successive formation of secondary right bending splays to the north as the active depocenter of the dead sea basin migrates northward with time

millennial scale iron fertilization of the eastern equatorial pacific over the past 100 000 years productivity in the eastern equatorial pacific is limited by the availability of iron geochemical analyses of a 100 000 year long sediment core suggest that pulses of dust deposition during heinrich stadials fuelled primary productivity

geology and evolution of the southern dead sea fault with emphasis on subsurface structure the dead sea fault is an active transform fault linking opening in the red sea with collision in the taurus zagros mountains motion is left lateral and estimated at approximately 5 7 mm year 1 the fault is seismically active and can be divided into two distinct structural segments this study focuses on the southern segment based mainly on the wealth of geophysical data owing to transtention caused by oblique slip and the overlapping of en echelon fault strands a series of pull apart basins were formed along the fault s length these basins are long and deep reaching in places more than 10 km deep they are characterized by extensional compressional and asymmetrical structures varying in size from large scale defining the general structure of the dead sea fault valley to small scale defining the internal structure this study examines the internal structure of these basins from south to north and summarizes the state of knowledge to date

coastal sea surface temperature warming trend along the continental part of the atlantic arc 1985 2005 1 coastal warming was analyzed by means of satellite derived sea surface temperature sst along the continental part of the atlantic arc extending from 37 n to 48 n for the period 1985 2005 interannual sst variability calculated from anomalies shows an inhomogeneous warming trend in coastal sst sst coastal warming trend ranges from 3 5 c 100 a 1 at latitudes close to 48 n to 1 2 c 100 a 1 at latitudes close to 37 n this warming is observed to reflect oceanic sst which increases northward in the atlantic area in addition a westward increase was also observed across the north atlantic coastal warming is not constant all year long it only occurs during spring and summer in the entire area under scope following a trend similar to the annual one the mean spring sst values are 5 1 c 100 a 1 in the french coast 4 4 c 100 a 1 in the cantabrian coast and 3 8 c 100 a 1 in the western iberian peninsula coast similar values 5 0 c 100 a 1 3 7 c 100 a 1 and 2 7 c 100 a 1 are observed in summer

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

quaternary transform kinematics constrained by sequence stratigraphy and submerged coastline features the gulf of aqaba abstract the dead sea fault system dsfs steps over at the northern head of the gulf of aqaba goa crossing the evolving continental shelf we report detailed processing and interpretation of high resolution sub bottom profiles of the north western tip of the goa down to a depth of about 120 m our data reveal stepping seafloor morphology comprising a series of relict coastline features primarily fossil reefs whose present depth results from the combined effect of sea level rise and tectonic displacements on the northern slope the fossil reefs are embedded in a predominantly single phase 30 m thick retrograde sedimentary stack that evolved presumably during sea level rise since the last glacial maximum about 20 ka large variations in character within this sedimentary stack bear evidence for large episodic changes in the rates of sea level rise and ensuing environmental conditions during the holocene a prominent terrace and face a suggested relict coastline feature accommodated on the order of 10 m down to the east vertical offsets across the surveyed area at the north western goa since submergence presumably late pleistocene to early holocene the trace of an active strike strike slip fault crossing the northern slope is defined by a ne striking bathymetric features b discontinuities offsetting the sedimentary layering from just below the sea floor to the deepest layers imaged c a 30 10 m sinistral and 10 1 m down to the west offset of a fossil reef at a depth of about 65 m global sea level curves constrain the age of the 65 m deep reef to 11 5 2 ka yielding an estimated average holocene sinistral slip rate of 2 7 1 5 mm yr about half the regional slip of the dsfs we conclude that the submarine fault defined here is a principal strand of the dsfs a southward left stepping echelon of the avrona fault such secondary echelon segmentation may be typical for the accommodation of strike slip at tips of transform basins

young faults in the hula pull apart basin central dead sea transform abstract the geometry and nature of structural features inside the hula pull apart basin at the central dead sea transform are presented here two systems of n s left lateral strike slip faults are located on the east and west sides of the hula basin both fault systems are composed of several segments arranged in a right stepping en echelon pattern the northern end of each segment is bent northeastward and usually merges with the next segment elevated regions and small hills appear on the northern side of each bend the strike slip faults are oblique with both vertical and horizontal components the vertical component may be normal or reverse although the hula valley is subjected to general extension the studied structures indicate local compression inside the basin normal faults striking e w comprise the northern border of the hula basin age determination of displaced travertines and basalts along the faults indicates sub recent tectonic activity and suggests migration of normal faulting towards the inner part of the basin the youngest fault displaces travertine dated at 25 300 years

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

temporal variation in the geometry of a strike slip fault zone examples from the dead sea transform abstract the location of the active fault strands along the dead sea transform fault zone dst changed through time in the western margins of dead sea basin the early activity began a few kilometers west of the preset shores and moved toward the center of the basin in four stages similar centerward migration of faulting is apparent in the hula valley north of the sea of galilee as well as in the negev and the sinai peninsula in the arava valley seismic surveys reveal a series of buried inactive basins whereas the current active strand is on their eastern margins in the central arava the centerward migration of activity was followed by outward migration with pleistocene faulting along nne trending faults nearly 50 km west of the center largely the faulting along the dst which began in the early middle miocene over a wide zone of up to 50 km became localized by the end of the miocene the subsidence of fault controlled basins which were active in the early stage stopped at the end of the miocene later during the plio pleistocene new faults were formed in the negev west of the main transform they indicate that another cycle has begun with the widening of the fault zone it is suggested that the localization of faulting goes on as long as there is no change in the stress field the stresses change because the geometry of the plates must change as they move and consequently the localization stage ends the fault zone is rearranged becomes wide and a new localization stage begins as slip accumulates it is hypothesized that alternating periods of widening and narrowing correlate to changes of the plate boundaries manifest in different euler poles

changes in global surface temperature from 1880 to 1977 derived from historical records of sea surface temperature abstract a preliminary analysis based primarily on historical records of sea surface temperature sst gives estimates of the change since 1880 of global hemispheric and zonal average surface temperatures the global change with time is roughly similar in shape and magnitude to that derived by mitchell from land station data alone but lags the mitchell curve by 10 20 years that is the present data show a minimumof temperature somewhere between 1900 and 1925 and a maximum somewhere between 1945 and 1970 comparing the means of these 25 year periods the rise from minimum to maximum was roughly 0 6 k for the northern hemisphere and 0 9 k for the southern hemisphere comparing the means of the 50 years before 1930 and the 48 years from 1930 to 1977 the rise was 0 3 k for the northern hemisphere and 0 6 k for the southern hemisphere the figures do not take into account the polar regions which on linear extrapolation from lower latitudes may have risen in temperature by twice the hemispheric averages

upper cretaceous campanian phosphorites in jordan implications for the formation of a south tethyan phosphorite giant a record of sedimentary authigenic and biological processes are preserved within the upper cretaceous campanian alhisa phosphorite formation ap in central and northern jordan the ap formed near the eastern extremity of the south tethyan phosphorite province stpp a carbonate dominated upper cretaceous to eocene phosphorite giant that extends from colombia north africa to the middle east multidisciplinary research of the ap and associated cherts chalks and oyster buildups indicate that phosphatic strata formed on a highly productive storm dominated east west trending epeiric platform along the south tethyan margin the onset of phosphogenesis and the accumulation of economic phosphorite coincided with a rise in relative sea level that onlapped peritidal carbonates of the ajlun group pristine phosphates are associated with well developed micrite concretionary horizons and contain abundant non keeled spiral planktic foraminifera and a low diversity benthic assemblage of buliminacean foraminifera suggesting that pristine phosphates are a condensed facies and phosphogenesis was stimulated by the effects of a highly productive surface ocean and the suboxic diagenesis of sedimentary organic matter the bulk sediment composition and absence of fe bearing authigenic phases such as glauconite pyrite including pyrite molds siderite and goethite within pristine phosphates suggests that deposition and authigenesis occurred under conditions of detrital starvation and that iron pumping played a minimal role in phosphogenesis authigenic precipitation of phosphate occurred in a broad array of sedimentary environments herein termed a phosphorite nursery that spanned the entire platform this is a non uniformitarian phenomenon reflecting precipitation of sedimentary apatite across a wide depositional spectrum in a variety of depositional settings wherever the conditions were suitable for phosphogenesis sedimentologic data indicate that pristine phosphates were concentrated into phosphatic grainstones through storm wave winnowing and storm generated shelf parallel geostrophic currents economic phosphorites formed through the amalgamation of storm induced event beds stratigraphic packaging of phosphatic strata indicates that temporal variations in storm frequency were a prerequisite for the formation of economic phosphorite syndepositional phosphogenesis reworking and amalgamation to form phosphorites contrasts sharply with the principles of baturin cycling a transgressive systems tract coupled with high surface productivity created detritally starved settings favourable for phosphogenesis storm reworking of pristine

continuum calculations of continental deformation in transcurrent environments a thin viscous sheet approximation is used to investigate continental deformation near a strike slip boundary the vertically averaged velocity field is calculated for a medium characterized by a power law rheology with stress exponent n driving stresses include those applied along boundaries of the sheet and those arising from buoyancy forces related to lateral differences in crustal thickness calculations are performed with either velocity or stress prescribed on the transcurrent boundary exact and approximate analytic solutions for a region with a sinusoidal strike slip boundary condition are compared with solutions for more geologically relevant boundary conditions obtained using a finite element technique the across strike length scale of the deformation is approximately 1 4 n 1 2 times the dominant wavelength of the imposed strike slip boundary condition for both the analytic and the numerical solutions this result is consistent with length scales observed in continental regions of large scale transcurrent faulting an approximate linear relationship between displacement and rotation is found that depends only on the deformation length scale and the rheology calculated displacements finite rotations and distribution of crustal thicknesses are consistent with those observed in the region of the pacific north america plate boundary in california

the palaeoecology of the callovian and oxfordian strata of majdal shams syria and its implications for levantine palaeogeography and tectonics abstract palaeoecological study of fossils from jurassic strata of majdal shams syria reveals a deepening and shallowing sequence of water conditions from callovian to tithonian time maximum water depth apparently occurred in the lower oxfordian where both fossils and lithology are typical of the deeper water parts of the tethys the contrast with very shallow facies nearby in lebanon is very marked the only acceptable palaeogeographic reconstruction of this region is obtained by accepting the widely proposed post jurassic 110 km sinistral strike slip movement on the dead sea fault on this reconstruction the majdal shams region becomes an extension of the basinal tethys along the nw se trending kishon jezreel graben this is strong evidence for tensional ne sw movements in the levantine area long before the miocene opening of the red sea

ground penetrating radar investigation of active faults along the dead sea transform and implications for seismic hazards within the city of aqaba jordan abstract ground penetrating radar gpr was used in an effort to locate a major active fault that traverses aqaba city jordan measurements over an exposed trenched cross fault outside of the city identify a radar signature consisting of linear events and horizontal offset flexured reflectors both showing a geometric correlation with two known faults at a control site the asymmetric linear events are consistent with dipping planar reflectors matching the known direction of dip of the faults however other observations regarding this radar signature render the mechanism generating these events more complex and uncertain gpr measurements in aqaba city were limited to vacant lots seven gpr profiles were conducted approximately perpendicular to the assumed strike of the fault zone based on regional geological evidence a radar response very similar to that obtained over the cross fault was observed on five of the profiles in aqaba city although the response is weaker than that obtained at the control site the positions of the identified responses form a near straight line with a strike of 45 although subsurface verification of the fault by trenching within the city is needed the geophysical evidence for fault zone location is strong the location of the interpreted fault zone relative to emergency services military bases commercial properties and residential areas is defined to within a few meters this study has significant implications for seismic hazard analysis in this tectonically active and heavily populated region

heinrich events massive late pleistocene detritus layers of the north atlantic and their global climate imprint 1 millennial climate oscillations of the glacial interval are interrupted by extreme events the so called heinrich events of the north atlantic their near global footprint is a testament to coherent interactions among earth s atmosphere oceans and cryosphere on millennial timescales heinrich detritus appears to have been derived from the region around hudson strait it was deposited over approximately 500 250 years several mechanisms have been proposed for the origin of the layers binge purge cycle of the laurentide ice sheet jokulhlaup activity from a hudson bay lake and an ice shelf buildup collapse fed by hudson strait to determine the origin of the heinrich events i recommend 1 further studies of the timing and duration of the events 2 further sedimentology study near the hudson strait and 3 greater spatial and temporal resolution studies of the layers as well as their precursory intervals studies of previous glacial intervals may also provide important constraints

sources of the large a d 1202 and 1759 near east earthquakes the sources of the may 1202 and november 1759 m 7 5 near east earthquakes remain controversial because their macroseismal areas coincide straddling subparallel active faults in the lebanese restraining bend paleoseismic trenching in the yammouneh basin yields unambiguous evidence both for slip on the yammou neh fault in the twelfth thirteenth centuries and for the lack of a posterior event this conclusion is supported by comparing the freshest visible fault scarps which imply more recent slip on the r chaiya serghaya system than on the yammouneh fault our results suggest that the recurrence of an a d 1202 type earthquake might be due this century as part of a sequence similar to that of a d 1033 1202 possibly heralded by the occurrence of the 1995 mw 7 3 aqaba earthquake the seismic behavior of the levant fault might thus be characterized by millennial periods of quiescence separated by clusters of large earthquakes

active tectonics of the yizre el valley israel using high resolution seismic reflection data abstract we present a series of high resolution seismic reflection lines across the yizre el valley which is the largest active depression in israel off the main trend of the dead sea rift the new seismic reflection data is of excellent quality and shows that the valley is dissected into numerous small blocks separated by active faults the yizre el valley is found to consist of a series of half grabens rather than a single half graben or a symmetrical graben the faults are generally vertical and appear to have a dominant strike slip component but some dip slip is also evident a marked zone of compression near megido is associated with the intersection of the two largest faults in the valley the carmel fault and the gideon fault variable trend of the faults reflects the complexity of the local geology along the boundary between the wide nw se trending farah carmel fault zone and the e w trending basins and ranges in the lower galilee this tectonic complexity is likely to result from a highly variable stress pattern modified by the structures inside it normal faulting in the valley occurred at an early stage of its development as a tectonic depression however strike slip motion on the carmel fault and possibly also on some of the other faults appears to have started together with the onset of normal faulting earthquake hazard in the area appears to be uniform as faults are distributed throughout the yizre el valley