searching for distal ejecta on the craton the sedimentary effects of meteorite impact abstractdistal ejecta from meteorite impacts are rare and hard to spot in the field because of their thinness 5 mm diameter sediments and produce high flow regime bedforms megaripples dunes upper plane beds and possi

identifying soft sediment deformation in rocks abstract the correct identification of sedimentary folds and fabrics created during gravity driven deformation of unlithified successions from those tectonic structures formed during regional deformation is essential when interpreting geological histories preserved within the rock record this topic has become increasingly relevant over the past 40 years as improved seismic resolution and coverage have led to the realisation that significant portions of unlithified sediments along the continental margins undergo gravity driven deformation to create mass transport deposits mtd s the late pleistocene lisan formation exposed in the dead sea basin was chosen as a case study because it remains poorly lithified and structures developed within it are unequivocally related to soft sediment deformation ssd created when the succession underwent downslope directed movement this work tests various assertions previously used to deduce if structures were formed in unlithified sediments or during hard rock deformation hrd associated with subsequent tectonism within the lisan formation we describe veins developed along fractures and cleavage forming axial planar to folds that are structures previously assumed to be restricted to hrd in addition truncated folds incorporation of deformed fragile fragments into overlying sediment and cross cutting clastic dykes are all indicative of ssd the key diagnostic feature in establishing ssd is the sedimentary infill of irregular erosive surfaces that truncate underlying structures although compaction and diagenesis have not played a significant role in the case study caution should be exercised when examining structures preserved in the rock record as folds and fabrics originally created by ssd may be considerably enhanced and altered where significant overburden exists

earthquake induced clastic dikes detected by anisotropy of magnetic susceptibility clastic dikes form either by passive deposition of clastic material into preexisting fissures or by fracturing and injection of clastic material during seismic shaking or passive overpressure because of their similar final geometry the origin of clastic dikes is commonly ambiguous we studied the mechanisms of clastic dike formation within the seismically active dead sea basin where hundreds of clastic dikes crosscut soft rock of the late pleistocene lacustrine lisan formation we analyzed the anisotropy of magnetic susceptibility ams of clastic dikes of known origin and defined characteristic ams signatures of depositional or injection filling we discovered that passively filled dikes which contain brownish silt resembling local surface sediments are characterized by an oblate ams ellipsoid and vertical minimum susceptibility axis v3 dikes that contain green clayey sediment connected to a mineralogically identical detrital layer of the lisan formation are characterized by a triaxial ams ellipsoid well grouped subhorizontal and parallel to the dike walls maximum susceptibility axis v1 and subvertical intermediate susceptibility axis v2 field evidence and ams analysis indicate that most of these dikes were emplaced by injection inferred to be due to seismically triggered fluidization this novel application of the ams provides a petrofabric tool for distinguishing passively filled dikes from injection dikes and where appropriate for identifying the latter as seismites

distribution of dynamic and static stress changes during 2000 tottori japan earthquake brief interpretation of the earthquake sequences foreshocks mainshock and aftershocks 1 the dynamic and static stress changes during the 2000 tottori earthquake have been recovered from the results of waveform inversion we use the dem to solve the elastodynamic equation specifying the slip along the fault obtained by a kinematic fault model the resulting shear stress distribution suggests an explanation of the foreshock and aftershock distributions we conclude that the fault zone heterogeneity is strong and most of the foreshocks and aftershocks were located in the zone of negative stress drop and mainly in the area surrounding the asperity this suggests that the asperity behaved as a barrier during the foreshocks and after the main shock the stress in the area surrounding the asperity increased and triggered most of the aftershocks the foreshock distribution was confined to a finite localized zone in the central part of the fault suggesting that this zone was bordered by barriers

estimates of stress drop of the chi chi taiwan earthquake of 20 september 1999 from near field seismograms the apparent stress and stress drop of the chi chi taiwan earthquake are estimated from near field seismograms the estimated apparent stress and stress drop for the southern part of the fault are about 100 bars lower than those for the northern part the estimated ratio e s m also suggests that there is a higher dynamic stress drop in the northern part than in the southern one this indicates the transformation of a higher percentage of strain energy into the seismic wave energy in the northern part than in the southern part based on a parameter proposed by ramon zuniga 1993 we propose that the stress model of frictional overshoot can interpret the rupture of the chelungpu fault on which the chi chi taiwan earthquake occurred manuscript received 31 july 2000

a coupled fluid fracture approach to propagation of clastic dikes during earthquakes abstract the propagation of clastic dikes was studied in ami az plain where hundreds of clastic dikes cross cut the soft rock of the late pleistocene lacustrine lisan formation within the seismically active dead sea basin two analytic models were established to estimate the dike propagation velocities the dike emplacement duration and the driving pressures that were associated with dike propagation either under laminar or turbulent flow conditions these models depend on the host rock and fluid properties dike width and length based on these properties and field limitations the results indicate that the dikes were propagated under turbulent flow conditions and propagation velocities of 4 65 m s the emplacement duration of the clastic dikes is between 0 8 and 2 s which is similar to the order of the acoustic wave duration that passes through the soft rock during an earthquake event this implies that the propagation of dikes could form during the passing acoustic waves and may thus be considered as an earthquake induced impact structures the calculated driving pressures that were generated during the earthquake events near the surface are 1 2 mpa one order of magnitude larger than the pressure due to the overburden on the source layer

large winds and wind shears caused by the nonlinear interactions between gravity waves and tidal backgrounds in the mesosphere and lower thermosphere a two dimensional nonlinear numerical model was used to simulate large winds 100m s 1 and wind shears 40m s 1 km 1 in the mesosphere and lower thermosphere mlt that are caused by the interaction between gravity waves gws and migrating tidal background by varying the wavelengths of gws and the phases of diurnal and semidiurnal tides 64 numerical experiments were performed our numerical experiments indicate that both migrating diurnal and semidiurnal tides strongly modulate the occurrence of gw breaking and the resulted large winds and wind shears the simulated large winds and wind shears are in good agreement with those from the rocket sounding chemical release measurements moreover the occurrence of large wind shears highly depends on the phases of migrating tides in local time which is in agreement with the reported lidar observations the local time dependence of large wind shears is mainly attributed to the filtering and or hindering effects of diurnal and semidiurnal tidal winds on gws our simulation reveals that the nonlinear interactions between gws breaking and the migrating diurnal and semidiurnal tides may play an important role in driving the large winds and wind shears in the mlt region and their local time dependence

large wind shears and stabilities in the mesopause region observed by na wind temperature lidar at midlatitude 1 unexpected large horizontal winds and wind shears in the lower thermosphere have been observed by rocket soundings and lidars for decades from 4 years of the colorado state university sodium wind temperature lidar data set 2002 2005 total of 1600 nocturnal h we observed an altitude distribution of high wind velocity and wind shears between 80 and 105 km similar to the results of chemical release experiments our lidar data show conclusively that when the observed wind shears are plotted as a function of the squared brunt vaisala frequency n2 they are below the value corresponding to the richardson number of 1 4 which is a necessary condition of the onset of dynamic instability this suggests that large wind shears can be sustained in the region of high static stability for example in the lower thermosphere where large wind shears are often observed by rocket sounding the full diurnal cycle lidar data enable the extraction of tidal wave components with periods of 24 12 8 and 6 h therefore allowing us to reveal the strong correlation of 60 between large wind shears 50 m s 1 km 1 and tidal waves the lidar measured seasonal variation in n2 and tidal amplitudes in the mesosphere and lower thermosphere are found to be consistent with the difference in altitude distribution of strong wind shears between winter and summer

verification of large scale rapid transport in the lower thermosphere tracking the exhaust plume of sts 107 from launch to the antarctic 1 new analysis of the doppler shift of o2 airglow spectra recorded by the timed doppler interferometer tidi and the high resolution doppler imager hrdi have provided conclusive evidence that the shuttle main engine exhaust plume generated in the lower thermosphere by the launch of sts 107 and imaged by the global ultraviolet imager guvi instrument on timed was transported to the antarctic in 80 h supporting a key inference from the initial study by stevens et al 2005 these new results were aided by improved knowledge of the effects of instrumental and satellite artifacts imposed on the doppler spectra sts 107 launched on 16 january 2003 and the neutral wind near its launch trajectory and nearby volume was sampled within minutes by tidi these initial observations suggested that the northernmost end of the shuttle s exhaust plume would move northeast and that the southern end would move southeast motions that were identified in imagery acquired during the next orbit of timed the direction and magnitude of plume motion inferred from guvi images obtained 12 26 and 50 h after launch were again confirmed by tidi and hrdi the appearance of the plume over the antarctic 80 h after launch inferred from earlier work by the appearance of iron ablated from the shuttle s main engines was consistent with neutral winds measured by the satellite doppler instruments over the antarctic the transport of the plume from the coast of florida to the antarctic was aided by the favorable phase and strong amplitude of a 2 day planetary wave of wave number three in the southern hemisphere on 18 january 2003 the existence of the 2 day wave was deduced from zonally averaged and combined tidi and hrdi neutral wind observations we conclude that the existence of strong and sustained winds in the mlt significantly greater than expected from empirical and theoretical models is indisputable and provides compelling evidence supporting the global scale nature of thermospheric winds with magnitude greater than 100 m s observed by larsen 2002 from 40 years of sounding rocket chemical release experiments

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

on steady homogeneous sand water flows in a vertical conduit in this paper an idealized model of the steady state phase of the flow in a vertical conduit leading to a sand volcano eruption is developed from first principles the model assumes that a sand water mixture flows upwards driven by an overpressure at the base of a vertical cylindrical conduit or a two dimensional fracture and opposed by gravity viscous resistance and turbulent drag the conditions for flow are analysed in detail and the mechanisms controlling the eruption rates are studied quantitatively the flow predictions are in accordance with our observations of analogous vigorous sand eruptions at deepwater oil fields for sufficiently high flow velocities u 10ut and small sand fractions s 0 2 the flow may be well mixed and homogeneous if these conditions are not met the flow may either become two phase or does not develop combining geological considerations with the steady homogeneous model it is possible to predict the behaviour of the vigorous quasi steady stage of a sand volcano eruption it is shown that based on the average density of the overlying sediments there are a range of overpressures for which sand volcanoes may develop

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

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

sedimentary and structural controls on seismogenic slumping within mass transport deposits from the dead sea basin abstract comparatively little work has been undertaken on how sedimentary environments and facies changes can influence detailed structural development in slump sheets associated with mass transport deposits mtds the nature of downslope deformation at the leading edge of mtds is currently debated in terms of frontally emergent frontally confined and open toed models an opportunity to study and address these issues occurs within the dead sea basin where six individual slump sheets s1 s6 form mtds in the late pleistocene lisan formation all six slumps which are separated from one another by undeformed beds are traced towards the ne for up to 1 km and each shows a change in sedimentary facies from detrital rich in the sw to more aragonite rich in the ne the detrital rich facies is sourced predominantly from the rift margin 1 5 km further sw while the aragonite rich facies represents evaporitic precipitation in the hyper saline lake lisan the stacked system of mtds translates downslope towards the ne and follows a pre determined sequence controlled by the sedimentary facies each individual slump roots downwards into underlying detrital rich layers and displays a greater detrital content towards the sw which is marked by increasing folding while increasing aragonite content towards the ne is associated with more discrete thrusts the mtds thin downslope towards the ne until they pass laterally into undeformed beds at the toe the amount of contraction also reduces downslope from a maximum of 50 to

an empirical model of the earth s horizontal wind fields hwm07 1 the new horizontal wind model hwm07 provides a statistical representation of the horizontal wind fields of the earth s atmosphere from the ground to the exosphere 0 500 km it represents over 50 years of satellite rocket and ground based wind measurements via a compact fortran 90 subroutine the computer model is a function of geographic location altitude day of the year solar local time and geomagnetic activity it includes representations of the zonal mean circulation stationary planetary waves migrating tides and the seasonal modulation thereof hwm07 is composed of two components a quiet time component for the background state described in this paper and a geomagnetic storm time component dwm07 described in a companion paper

simulation of seismic wave propagation through geometrically complex basins the dead sea basin abstract the dead sea transform dst is the source for some of the largest earthquakes in the eastern mediterranean the seismic hazard presented by the dst threatens the israeli palestinian and jordanian populations alike several deep and structurally complex sedimentary basins are associated with the dst these basins are up to 10 km deep and typically bounded by active fault zones the low seismicity of the dst the sparse seismic network and limited coverage of sedimentary basins result in a critical knowledge gap therefore it is necessary to complement the limited instrumental data with synthetic data based on computational modeling in order to study the effects of earthquake ground motion in these sedimentary basins in this research we performed a 2d ground motion analysis in the dead sea basin dsb using a finite difference code cross sections transecting the dsb were compiled for wave propagation simulations results indicate a complex pattern of ground motion amplification affected by the geometric features in the basin to distinguish between the individual contributions of each geometrical feature in the basin we developed a semiquantitative decomposition approach this approach enabled us to interpret the dsb results as follows 1 ground motion amplification as a result of resonance occurs basin wide due to a high impedance contrast at the base of the uppermost layer 2 steep faults generate a strong edge effect that further amplifies ground motions 3 sub basins cause geometrical focusing that may significantly amplify ground motions and 4 salt diapirs diverge seismic energy and cause a decrease in ground motion amplitude

fold and thrust systems in mass transport deposits abstract improvements in seismic reflection data from gravity driven fold and thrust systems developed in offshore mass transport deposits mtds reveal a number of significant features relating to displacement along thrusts however the data are still limited by the resolution of the seismic method and are unable to provide detail of local fold and thrust processes investigation of exceptional gravity driven contractional structures forming part of mtds in lacustrine deposits of the dead sea basin enables us to present the first detailed outcrop analysis of fold and thrust systems cutting unlithified soft sediments we employ a range of established geometric techniques to our case study including dip isogons fault propagation fold charts and displacement distance diagrams previously developed for investigation of thrusts and folds in lithified rocks fault propagation folds in unlithified sediments display tighter interlimb angles compared to models developed for lithified sequences values of stretch which compares the relative thickness of equivalent hangingwall and footwall sequences measured along the fault plane may be as low as only 0 3 which is significantly less than the minimum 0 5 values reported from thrusts cutting lithified rocks and reflects the extreme variation in stratigraphic thickness around thrust related folds we suggest that the simple shear component of deformation in unlithified sediments may modify the forelimb thickness and interlimb angles to a greater extent than in lithified rocks the average spacing of thrust ramps and the thickness of the thrust sequence display an approximate 5 1 ratio across a range of scales in mtds in general thicker hangingwall and footwall sequences occur with larger thrust displacements although displacement patterns on thrusts cutting unlithified yet cohesive sediments are more variable than those in lithified rocks line length restoration of thrust systems in mtds reveals 42 shortening which reduces to 35 in overlying beds a 23 reduction in shortening by folding and thrusting along individual thrusts suggests that heterogeneous lateral compaction may increase by 10 towards the sediment surface thrust systems cutting unlithified sediments display distinct steps in cumulative displacement distance plots representing increased rates of slip along the floor thrust while displacement distance plots along individual thrusts also reveal horizontal steps relating to lithological variation competent units cut by thrust ramps may display the greatest displacement which then progressively reduces both upward and sometimes downward along the ramp this relationship demonstrates that ramps do not necessarily propagate upwards from the underlying flat as in some traditional models but rather initiate by offset of competent horizons in the hangingwall of the detachment critical taper angles in mtds may be an order of magnitude less than in accretionary complexes or lithified rocks overall thrusts cutting unlithified sediments in mtds display more variable displacement and more pronounced displacement gradients toward fault tips compared to thrusts cutting lithified sequences

source parameters of the 15 november 1995 border town nevada earthquake sequence abstract the november 1995 border town nevada earthquake sequence occurred near the california nevada border approximately 20 km northwest of reno nevada the largest earthquake of the sequence m w 4 5 was widely felt throughout the reno sparks truckee region this event occurred on a west dipping high angle fault at a depth of 14 km and shows dip slip motion on a preferred fault plane orientation of strike n10 e dip 70 w and rake 75 we have relocated 27 aftershocks and one foreshock of the event using records from the local network and two portable digital instruments the largest aftershocks also align along a n10 e trend and define the preferred fault plane all of the aftershocks occur within a small volume with a 2 by 2 km horizontal extent and between depths of 10 and 14 km simultaneous determination of m 0 f c and is made by fitting spectra using various starting models i e initial s and based on an f 2 spectral shape m 0 ranges from 10 18 to 10 23 dyne cm for 14 events and hypocentral distances were less than 15 km we fit s wave spectra with different starting models to test the stability of s the results show that s and converged to different values depending on the starting model and the magnitude because of an attenuation source dimension trade off for example a model starting with a stress drop of 10 bars produced an average s of 27 bars and an apparent scaling breakdown below m w 3 starting the search at 50 bars produced an average s of 69 bars and no magnitude dependence we cannot resolve any breakdown in self similarity because we find plausible spectral models for all magnitudes where s is nearly constant at 60 bars seismograms of the four largest aftershocks m w 3 0 to 3 4 were deconvolved using smaller aftershocks as empirical green9s functions event radii estimated from the pulse widths yield stress drop averaging 34 bars within the range of the frequency domain results

intense winds and shears in the equatorial lower thermosphere measured by high resolution nonspecular meteor radar large horizontal winds and wind shears have been measured in the lower thermosphere by rockets lidars and nonspecular meteor radars this paper describes a detailed analysis of three multihour nonspecular meteor radar data sets collected at the jicamarca radio observatory this provides some of the highest resolution sustained measurements in this part of the atmosphere these show 1 intense wind speeds maintaining 180 m s for half an hour and 160 m s for another half an hour 2 winds structured in layers that move up or more commonly down in the predawn hours at rates of a few kilometers per hour 3 intense wind shears that typically persist at around 50 m s km but in one instance sustains values approaching 100 m s km for a few hours

enigmatic earthquake generated large scale clastic dyke in the biberach area sw germany abstract we discovered and describe a large scale exposed dimensions 17 m in lateral and 15 m in vertical extension and up to 10 cm in width clastic dyke in the middle miocene between 17 1 and 14 5 ma sandy deposits fluviatile untere serie of the north alpine foreland basin close to biberach an der ris in sw germany the dyke appears to be of sedimentary tectonic origin it formed by liquefaction and injection of clastic material that occurred simultaneously with fracture opening and propagation in sandy deposits presumably as a result of strong seismic shaking triggered by an intense earthquake we therefore interpret the dyke as a seismite and a useful palaeoseismic indicator the clastic dyke cuts through a layer of distal ries ejecta brockhorizont and thus postdates the ries impact the age of the ries event in combination with other stratigraphic constraints defines a relatively narrow time frame of 14 8 to 14 5 ma for the formation of the clastic dyke the source of the strong earthquake responsible for dyke formation might be seismicity related to the alpine orogeny and tectonism seismic activity in one of the volcanic fields of the paleogene to quaternary european volcanic province or seismicity induced by a miocene impact event in southern germany we suggest the relatively strong earthquake in question may have been triggered by a large phreatomagmatic explosion in the urach kirchheim volcanic field or perhaps more likely the steinheim impact event on the eastern swabian alb plateau

hydrocode simulations of chicxulub crater collapse and peak ring formation we use hydrocode modeling to investigate dynamic models for the collapse of the chicxulub impact crater our aim is to integrate the results from numerical simulations with kinematic models derived from seismic reflection and wide angle velocity data to further our understanding of the formation of large impact craters in our simulations we model the collapse of a 100 km diameter bowlshaped cavity formed in comprehensively fractured crustal material to facilitate wholesale collapse we require that the strength of the target be significantly weakened in the present model we achieve this using acoustic fluidization where strong vibrations produced by the expanding shock wave cause extreme pressure fluctuations in the target at times and positions where the overburden pressure is sufficiently counteracted the frictional resistance is reduced enabling the rock debris to flow our simulations produce a collapsed crater that contains most of the features that we observe in the seismic data at chicxulub in particular we observe a topographic peak ring formed as material that is originally part of the central uplift collapses outward and is thrust over the inwardly collapsing transient crater rim this model for peak ring generation has not been previously demonstrated by numerical simulations and predicts that the peak ring is composed of deeply derived material and that the stratigraphy within the peak ring is overturned c 2002 elsevier science usa

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

dynamical weakening of faults by acoustic fluidization when a fault slips seismically some of the energy released may excite strong short wavelength vibrations near the fault core such vibrations can temporarily reduce the normal stress on the fault allowing it to slip at lower shear stresses than predicted by laboratory coefficients of friction this phenomenon of acoustic fluidization provides an alternative to theories that invoke pressurized fluids as an explanation for why some faults appear to be so weak

magnetic fabric anisotropy of magnetic susceptibility constraints on emplacement mechanism of clastic dikes clastic dikes are generally classified into neptunian and injected dikes using the magnetic fabrics ams anisotropy of magnetic susceptibility we attempt to classify the clastic dikes in the late cretaceous dadaepo basin se korea and interpret their emplacement mechanisms the neptunian dikes exhibit a typical oblate sedimentary fabric which makes a sharp contrast with the injected dikes the fabrics of the injected dikes are greatly influenced by current conditions and transportation types of filling materials based on the ams fabrics they are classified into four types 1 vp vertical flow parallel type is formed by imbrication of long axis of grains in low to moderate energy vertical flow of a newtonian fluid and characterized by a bilateral symmetry of fabrics across the dike 2 vt vertical flow transverse fabric type results from grain rolling in vertical high energy flow and is characterized by subvertical k2 and subhorizontal k1 axes on the dike plane 3 hp horizontal flow parallel type is formed by imbrication of long axis of grains in horizontal low to moderate energy flow resulting in subvertical k3 and subhorizontal k1 and k2 axes 4 ht horizontal flow transverse type is formed by grain rolling in horizontal high energy flow resulting in streaked k2 k3 on the dike plane and horizontally clustered k1 axes the ams fabrics of each type can be a significant indicator for flow direction based on abundant ams fabrics formed by high energy current coexistence of paleoseismic structures and tectonic setting of the basin earthquake induced liquefaction is the most plausible trigger for the dike formation

mechanisms and controls on the formation of sand intrusions sandstone intrusions are found in all sedimentary environments but have been reported most commonly from deep water settings they also appear to be more frequently developed in tectonically active settings where applied tectonic stresses facilitate development of high fluid pressures within the sediments a variety of mechanisms have been cited as triggers for clastic intrusions these include seismicity induced liquefaction application of tectonic stresses excess pore fluid pressures generated by deposition related processes and the influx of an overpressured fluid from deeper within the basin into a shallow sand body the formation of sandstone dykes and sills is investigated here by considering them as natural hydraulic fractures when the seal on an unconsolidated overpressured sand body fails the resulting steep hydraulic gradient may cause the sand to fluidize the fluidized slurry can then inject along pre existing or new fractures to form clastic intrusions the scale and the geometry of an intrusive complex is governed by the stress state depth and pre existing joints or faults within the sedimentary succession as well as the nature of the host sediments for the simplest tectonic setting where the maximum stress in a basin is vertical gravitational loading small irregular intrusions commonly result in the formation of sills at shallow depths within a few metres of the surface whereas at greater depth dykes and sills forming clastic intrusion networks are more typical a simple relationship is derived to calculate the maximum burial depth at which a dyke sill complex forms as a function of the source bed to sill height the bulk density of the surrounding sediments and the ratio of the vertical to horizontal effective stresses k 0 when applied to three examples of large scale dyke sill complexes developed within paleocene and eocene deep water reservoir sand bodies of the north sea maximum burial depths in a range of 375 to c 500 m 450 700 m and 550 850 m are estimated for intrusion of each of the three complexes

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

upslope verging back thrusts developed during downslope directed slumping of mass transport deposits acknowledgements sm acknowledges the israel science foundation isf grant no 1436 14 and the ministry of national infrastructures energy and water resources grant 214 17 027 rw was supported by the israel science foundation isf grant no 1245 11

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

distinguishing coeval patterns of contraction and collapse around flow lobes in mass transport deposits abstract gravity driven mass transport deposits mtds form by the downslope directed movement of sediment associated with slope failure simple models suggest that extension forms at the upslope head area contraction is focussed in the downslope toe of the slump while differential shear associated with strike slip is restricted to the lateral margins of the slump although the head and toe are considered to be dominated by layer parallel shear lps differential layer normal shear lns may be generated around the lateral margins of slumps and potentially also within mtds where flow has been separated into different lobes despite this realisation that lns must form there has been little work into the geometries and spatial relationships of resulting structures using the late pleistocene lisan formation exposed around the dead sea basin as our case study we examine detailed

soft sediment deformation structures interpreted as seismites in middle late pleistocene aeolian deposits apulian foreland southern italy abstract soft sediment deformation structures in middle late pleistocene deposits of torre san gennaro brindisi southern italy have been analysed from a morphologic point of view the deformational structures are represented by deformed cross bedding and large injection structures they are restricted to aeolian sediments and the mechanism of deformation is related to liquefaction and or fluidization processes the liquefaction and or fluidization processes have been interpreted as seismic induced after consideration of all other possible trigger agents the discussion about the possible source areas of the palaeoseismic event was carried out through the analysis both of the general magnitude distance relations and the main structural features of the study zone in conclusion we consider the key criteria for trigger mechanism interpretation of soft sediment deformation structures in aeolian deposits and the actual feasibility of using aeolian sediments for the palaeoseismic studies

large wind shears and their implications for diffusion in regions with enhanced static stability the mesopause and the tropopause the ncar whole atmosphere community climate model waccm with a quasi uniform horizontal resolution of 25km and a vertical resolution of 0 1 scale height produces large vertical shear of horizontal wind with peaks around the mesopause and the tropical and midlatitude tropopause in these regions the static stability also reaches peak values and therefore allows large vertical shears before the onset of dynamical instability the wind shear peaks near the mesopause and the tropopause from the simulation compare well with those identified in observations including the magnitude latitudinal dependence and large shear statistics by analyzing the probability density functions of the wind shears and their dependence on the zonal scales it is found that smaller scale processes likely gravity waves contribute significantly to the large shears and may play a dominant role in producing the largest shears climatological tidal waves have secondary contribution to the large winds and shears but spectral analysis suggests that they can modulate wind shear perturbations by gravity waves in the mesosphere and lower thermosphere implications for tracer transport and mixing in these regions are explored by estimating diffusion coefficients based on the root mean square winds shears and corresponding spatial scales from model results

a comparison of lower thermospheric winds derived from range spread and specular meteor trail echoes 1 interferometry measurements of range spread meteor trail echoes rstes also known as nonspecular echoes have provided new insights into both the irregularity structures in meteor trails and lower thermospheric winds ltws in this study we used trail echoes observed with the newly installed sanya 18 4 n 109 6 e 47 5 mhz vhf coherent radar and the sanya all sky meteor radar to estimate instantaneous zonal and hourly averaged meridional winds from rstes and hourly averaged zonal and meridional winds from large numbers of specular meteor echoes the mean height variations in both the zonal and meridional winds estimated from the rstes were generally consistent with those estimated from specular meteor echoes below 96 km this gives validity to the technique proposed recently by oppenheim et al 2009 and suggests that rste measurements made with a small radar can be used to investigate ltws whereas this had previously been limited to larger radars such as the jicamarca radar however some observations show significant differences in wind magnitude at individual heights at times the results of rste measurements show the presence of an intense westward wind with a speed near 100 ms 1 in contrast the specular meteor zonal winds were generally less than 50 ms 1 on the other hand the meridional drift of rstes derived from the meridional doppler velocity at higher altitudes shows a very poor correlation with the specular meteor meridional wind potential causes for the discrepancy in wind estimates obtained from rste and specular meteor trail echoes are discussed

structural evolution of long duration meteor trail irregularities driven by neutral wind an experiment on spatial domain interferometry observations of meteor trail irregularities at a low latitude location in china was conducted during august 2013 using the sanya vhf coherent radar 18 4 degrees n 109 6 degrees e more than 3 thousand range spread meteor trail echoes rstes were observed among the trail echoes the spatial structure of meteor trail irregularities responsible for a single long duration rste event persisting for similar to 4min was reconstructed this rste was found to be initially generated at 90 115 km altitudes and aligned along the radar beam boresight after about the first minute of the trail lifetime the trail echo appeared only in a narrow altitude range of 94 98 km an analysis on the spatial pattern of the long duration rste showed that the trail irregularities at lower range gates moved away from the region perpendicular to the geomagnetic field the eastward drifts of the rste irregularities were found to decrease with increasing altitude e g from 80 ms 1 at similar to 94 km to 20 ms 1 at similar to 100 km simultaneous horizontal neutral wind measurements made with the fuke all skymeteor radar located north of sanya recorded a similar velocity profile we suggest that the neutral wind could drive the spatial structural evolution of the rste irregularities and help to determine the altitudes where the longest portion of the rste was located

influence of trench width on subduction hinge retreat rates in 3 d models of slab rollback subduction of tectonic plates limited in lateral extent and with a free trailing tail i e free subduction is modeled in a three dimensional 3 d geometry the models use a nonlinear viscoplastic rheology for the subducting plate and exhibit a wide range of behaviors depending on such plate characteristics as strength width and thickness we investigate the time evolution of this progressive rollback subduction measure the accompanying return flow in the upper mantle and quantify the plate kinematics due to the 3 d geometry flow is allowed to accompany slab rollback around the lateral edges of the slab the toroidal component as opposed to 2 d geometry where material is forced to flow underneath the slab tip the poloidal component a simple force balance is provided which relates the speed of backward trench migration to the resistive forces of generating flow and weakening the plate our results indicate most of the gravitational energy of the system i e the negative buoyancy of the subducting slab is converted into a toroidal flow 69 a much smaller amount goes into weakening the plate 18 and the remaining amount goes into driving flow parallel to displacement of the slab 13 for the trench widths w we investigate 1500 km a maximum trench retreat rate occurs for trenches 600 km wide which is attributed to the interaction between a plate of finite width and the induced flow which has a lengthscale in the horizontal direction these numerical results quantitatively agree with comparable 3 d laboratory experiments using analogue models with a purely viscous plate material schellart 2004a 2004b including correlations between increasing retreat rate with increasing plate thickness trench width for maximum retreat rate 500 km and estimated amount of slab buoyancy used to drive rollback induced flow 70 several implications for plate tectonics on earth result from these models such as rollback subduction providing a physical mechanism for ephemeral slab graveyards situated above the more viscous lower mantle and endothermic phase transition prior to a flushing event into the lower mantle mantle avalanche

on the large wind shear and fast meridional transport above the mesopause 1 unexpectedly strong winds shears and fast meridional transport above the mesopause have been revealed from previous rocket and satellite observations using richardson number criteria for dynamic stability we estimate the maximum wind shears allowable by the background static stability which peaks above the mesopause these maximum shears are in general agreement with the large wind shears inferred from the rocket measurements at low and mid latitudes indicating the close relationship between the latter and the stability constraint set by the background atmosphere diagnostic calculations also indicate that the meridional transport in this region may not be well understood solely by examining the mean meridional circulation and large amplitude tides planetary waves can play an important role in the bulk transport of tracers strong stochastic winds presumably due to gravity waves do not seem to significantly change the large scale pattern of the transport but may extend the range of the tracer movement

sandstone dykes as evidence of localized transtension in a transpressive regime bir zreir area eastern sinai the bir zreir area ne sinai is part of the 40 km wide eastern sinai shear zone stretching along the western margin of the gulf of elat sinistral movement along faults comprising this shear zone is consistent with the regional nnw sse compression in which the dead sea transform fault was formed in the bir zreir area sandstone dykes within ne striking fault breccias were developed within the precambrian crystalline basement these breccias up to 200 m in width resulted from transpression along the ne striking faults in response to sinistral movement along the nne striking major faults paradoxically the sandstone dykes developed by infilling of transtensional open fissures which share the ne trend of the breccia zones the source rock for the dykes is nubian sandstone unconformably overlying the basement the depth beneath the unconformity to which the sandstone collapsed is 500 600 m local nw se transtension along parts of the ne striking faults enabled the formation of fissures and their infilling by sand and sandstone blocks of various sizes as dykes the infilling occurred despite the regional nnw sse compression which prevailed in the study area a kinematic model is developed which combines sinistral movement and clockwise rotation of rigid blocks between the faults with resultant local nw se transtension along the northern segment of the ne trending strike slip faults

coseismic horizontal slip revealed by sheared clastic dikes in the dead sea basin despite the hazard caused by near surface destructive horizontal displacements during earthquakes field evidence for coseismic slip along horizontal discontinuities is exceptionally rare mainly due to the lack of adequate exposure and markers however within the seismically active dead sea basin the late pleistocene lisan formation contains vertical clastic dikes that are sheared laterally at maximum depths of 15 m and thereby provide unique profiles of such horizontal displacement in order to investigate how coseismic horizontal shearing is distributed near the surface we document an 1 m thick brittle shear zone consisting of up to 11 slip surfaces that can be traced for tens of meters in the lisan formation displacements along individual slip surfaces are up to 0 6 m and the total displacement across the shear zone is up to 2 0 m displacement profiles and gradients indicate that the brittle shear zone formed by simple shear and deformation was associated with slip partitioning and transfer between primary and secondary slip surfaces evidence for concurrent displacement along slip surfaces during a single event indicates that the brittle shear zone was formed during a coseismic event subsequent to 30 ka we consider the mechanical effect of seismic wave related transient stress which when added to the initial static effective stress may result in concurrent horizontal shear failure along detrital rich layers in the lisan formation the exceptional quality of exposures and markers enables us to document for the first time the details of near surface horizontal shearing and indicates that displacement along horizontal bedding planes is a viable mechanism to absorb coseismic deformation in well bedded near surface strata

a numerical model to simulate snow cover stratigraphy for operational avalanche forecasting laws of snow metamorphism have been introduced in a numerical model which simulates the evolution of temperature density and liquid water profiles of snow cover as a function of weather conditions to establish these laws the authors have summarized previous studies on temperature gradient and on wet snow metamorphism and they have also conducted metamorphism experiments on dry or wet fresh snow samples an original formalism was developed to allow a description of snow with parameters evolving continuously throughout time the introduction of laws of metamorphism has improved significantly the derivation of the settlement of internal layers and of snow covered albedo which depend on the simulated stratigraphy i e the type and size of snow grains of different layers of the snow cover the model was tested during a whole winter season without any re initialization comparison between the simulated characteristics of the snow cover and the observations made in the field are described in detail the model proved itself to be very efficient in simulating accurately the evolution of the snow cover stratigraphy throughout the whole winter season

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

seismically induced soft sediment deformation structures seismites around sumdo in the lower spiti valley tethys himalaya abstract soft sediment deformation structures were observed in 120 m thick fluvio lacustrine sediments exposed in the sumdo area in the lower spiti valley tethys himalaya himachal pradesh india these structures vary in their morphology and pattern and occur at eight stratigraphic levels s1 s8 spaced at irregular intervals the deformation structures include over steepened stratification diapiric flame like intrusions of clayey material or complex type recumbent folding of flame like nature pseudonodules large scale soft sediment folding faulting small scale associated with folding and sand dykes these structures are restricted to single stratigraphic layers separated by undeformed beds and can be correlated over a large distance the deformation of the soft sediments is attributed to the combined effects of fluidization liquefaction and shear stress and can be related to past seismic activity in the area recently on 19 january 1975 a major earthquake kinnaur earthquake of magnitude 6 8 caused extensive damage including ground rupturing in the sumdo kaurik area this earthquake has been related to the activation of the kaurik chango fault the deformed layers seismites reported here lie adjacent to this fault zone and can be related with episodic seismicity along this fault it is evident from this study that the kaurik chango fault has been re activated a number of times and that the area suffered at least nine major earthquakes with a magnitude of more than 6 during late pleistocene holocene time including the 1975 kinnaur earthquake

velocities and driving pressures of clay rich sediments injected into clastic dykes during earthquakes summary we studied the velocities and driving pressures associated with clastic dyke formation in the ami az plain where hundreds of clastic dykes cross cut the soft rock of the late pleistocene lacustrine lisan formation within the seismically active dead sea basin flow of clastic material into fractures and opening of the fractures are two mechanisms that occur during earthquake induced clastic dyke emplacement two analytic models were established based on field observations and experimental viscosity tests to estimate the velocities and driving pressures that were associated with dyke emplacement a a channel flow for upward injection of a clay water mixture and b a profile of fracture dilation based on the elastic theory analysis the two models predict that pressures between 1 and 10 mpa are generated in the source layer and dykes in the last stage of the injection process in addition the channel flow model predicts that the injection velocity reaches metres to tens of metres per second and the emplacement time of the clastic dykes is on a scale of seconds it is suggested that the high pressure values represent the static stress drop during earthquake events or represent dynamic stresses resulting from the seismic waves which passed through the soft lacustrine rocks in both cases the predicted high pressure values indicate that the clastic dyke was emplaced in close proximity of an active segment of the dead sea fault during the late pleistocene holocene

seismic observations of the 22 11 1995 gulf of aqaba earthquake sequence abstract we analyzed the aftershock sequence of the gulf of aqaba earthquake recorded by short period and broad band stations between november 1995 and december 1996 the seismicity pattern reveals significant activity often confined to known surface traces of active faults or within local grabens most of the aftershock activity is concentrated north of the main shock in the aragonese and eilat basins while the activity is diffused south of the main shock in the dakar and tiran basins most of the moderate to strong aftershocks of the whole aftershock sequence occurred in the aragonese basin mainly in the first 100 days following the main shock the eilat basin is characterized by a larger number of aftershocks composed mainly of small magnitude implying a slower decay rate assuming a detection level of ml 3 2 we obtain b values of 1 01 1 15 and 0 89 for the whole gulf of aqaba and eilat and aragonese basins respectively in good agreement with recent studies of the dead sea fault following omori s law we obtained a decay parameter of 0 94 0 88 and 0 96 for the aftershock sequences in the whole gulf of aqaba and the eilat and aragonese basins respectively correlative with regions of low heat flow for 1630 events in the local magnitude range of 0 6 ml 6 2 we found seismic moment estimates m0 of 5 1018 m0 7 7 1026 dyn cm and brune stress drop estimates between 1 and 200 bars with a characteristic value of 90 bars in the eilat and aragonese basins for m0 5 1021 dyn cm these characteristics are comparable to those for events occurring on the main dead sea jordan fault most of the moment release in the basins occurred shortly after the occurrence of the main shock the total moment release in the eilat and aragonese basins is only a fraction of the moment release of the main shock suggesting an almost complete stress release

estimates of source parameters for the 1999 chi chi taiwan earthquake based on brune s source model the general features of the rupture of the 1999 chi chi taiwan earthquake m s 7 6 can be explained by the displacement waveforms derived from the accelerograms recorded at short distances from the fault traces applying brune s model we have determined important source parameters such as rise time stress drop offset and particle velocity generally the earthquake is characterized as having had two distinct fault segments the southern segment dominated by thrust motion started from the focus on a fault plane raking at 78 and extended about 30 km to the north the northern segment dominated by thrust with significant strike slip motion began next to the end of the southern segment on a fault plane raking at 53 and extended northward for 25 km slips in the southern segment were followed by a small dislocation 1 m while those in the northern segment were followed by a much larger dislocation 9 m the average slip velocity was distributed at 34 49 cm sec along the southern segment and an unusual slip velocity exceeding 2 m sec was observed along the northern segment furthermore the southern segment experienced a rise time of 1 8 sec and a stress drop of 65 bars in contrast to a rise time longer than 4 sec and a stress drop larger than 300 bars registered to the north our results also indicate that along the southern segment the rupture propagated northward at an average velocity of 2 84 km sec but along the northern segment the rate declined to less than 2 km sec the difference in the source parameters between these two segments suggests that the rupturing associated with the chi chi earthquake may have encountered a resistive patch and changed course in the middle part of the fault after crushing that resistance the long rise time and high stress drop probably caused substantially slower motion and larger slip along the northern segment manuscript received 10 november 2000

u th dating of lake lisan late pleistocene dead sea aragonite and implications for glacial east mediterranean climate change u series dating can be an effective means to obtain accurate and precise ages on quaternary carbonates however most samples require a correction for u and th in admixed detritus this complication is often addressed through generation of u th isochrons requiring analyses of several coeval samples in addition presence of water derived hydrogenous th in the carbonate can cause inaccuracies in isochron ages this study reports a high resolution u series chronology of sediments deposited by lake lisan the last glacial precursor of the dead sea the strategy employed combines multiple measurements from a few stratigraphic heights and fewer analyses from many heights in a single described and measured section the resulting chronology is based on ages at 22 heights in a 40 m thick section covering the interval of 70 14 calendar ka bp the effects of admixed detritus are evaluated using trace elements nearly pure aragonite samples indicated by very low abundances of insoluble elements such as nb and zr were found to contain hydrogenous th which causes the uncorrected u 230th age of a modern sample to be 2 5 ka nevertheless accurate ages have been obtained by correcting for the detrital and aqueous interferences the resulting ages are in stratigraphic order and their accuracy is evidenced by consistency of lisan formation u series and 14c ages with the coral based calendar radiocarbon age calibration the u th ages provide a context to unravel the limnological history of lake lisan boundaries between the lower middle and upper stratigraphic units correspond to the mis 4 3 and 3 2 transitions respectively during mis 2 and 4 the lake generally showed a stable two layer configuration and a positive fresh water balance reflected by deposition of laminated aragonite detritus dry intervals during mis 2 and 4 are indicated by thick gypsum layers and an inferred depositional hiatus which are temporally associated with heinrich events h1 at 17 ka and h6 at 65 ka respectively during mis 3 the lake level was unstable with intermittent dry periods indicated by abundant clastic layers and a significant hiatus between 43 49 ka clastic layers are associated with dansgaard oeschger events during mis 3 and indicate lake level declines during abrupt northern hemisphere warmings overall the climate of the eastern mediterranean region shows a strong linkage to the northern hemisphere climate with increasing lake size and stability during cold periods and fluctuations and dessication during warmings and heinrich events

mechanical modeling and insar measurements of mount sedom uplift dead sea basin implications for effective viscosity of rock salt we present a mechanical model for the growth of an emerging salt diapir in a tectonically active basin the analytical model is applied to and serves to constrain the effective viscosity of rock salt and strain rates during diapirism of the wall shaped mount sedom rock salt diapir dead sea basin the model is based on one dimensional flow of newtonian viscous fluid salt in a vertical channel that has been driven by the load of the overburden and affected by shear along the channel walls because the poiseuille channel flow profile is parabolic and the couette shear flow profile is linear a one dimensional model provides three sets of predicted profiles topography uplift rate and shear strain the present topography of mount sedom represents the shape of the sedom diapir and hence the effective viscosity of rock salt can be constrained by a model that best fits the present topography of the mountain the resulting sedom rock salt viscosity is determined to be between 2 and 3 1018 pa s and the associated strain rate is between 5 and 6 10 13 s 1 geological structures indicate strain rates of 9 10 13 s 1 and 3 10 14 s 1 during the holocene emerging stage and at the plio pleistocene pre emergent stage of the sedom diapir respectively the uplift history of mount sedom predicted by the model and the current topography are compared to interferometric synthetic aperture radar insar measurements of salt uplift the maximum uplift rates of mount sedom are 8 3 and 5 5 mm yr for its northern and southern parts respectively the insar uplift profiles resemble topographic profiles obtained along the same traverses implying that the uplift history during the last 14 000 years is stable steep uplift gradients observed by insar along the western margin of the diapir are higher than predicted by modeling of newtonian viscous flow this could imply that flow of power law viscous fluid may be more suitable than that of newtonian viscous fluid for the sedom rock salt at high strain rates above 8 10 13 s 1

the rupture process during the 1999 duzce turkey earthquake from joint inversion of teleseismic and strong motion data abstract teleseismic and strong motion data are inverted to determine the rupture process during the november 1999 duzce earthquake in nw turkey the fault geometry rise time and rupture velocity are determined from the aftershock distribution and preliminary inversions of the teleseismic data joint inversion of the teleseismic and strong motion data is then carried out for the slip distribution we obtain the strike 264 dip 64 rake 172 seismic moment 5 0 1019 n m mw 7 1 and average stress drop 7 mpa this earthquake was characterized by bilateral fault rupture and asymmetric slip distribution two asperities areas of large slip are identified the eastern one being 1 5 times larger than the western one the derived slip distribution is consistent with the aftershock distribution surface rupture and damage the point of rupture initiation in this duzce earthquake coincided with the eastern tip of the aftershock distribution of the august 1999 izmit earthquake

bed parallel slip identifying missing displacement in mass transport deposits abstract bed parallel slip bps where neighbouring beds slide past one another along bedding planes is notoriously difficult to identify without reference to pre existing features such as steep faults or dykes that act as markers to record bps offset while bps is intuitively thought to operate during downslope sliding of mass transport deposits mtds in sedimentary basins there is a conspicuous lack of supporting outcrop or seismic data to corroborate this and bps displacement may therefore have remained unaccounted for this study addresses this gap in knowledge by investigating late pleistocene mtds developed around the dead sea basin and provides the first detailed analysis of bps that pervades a gravity driven setting in particular we examine the role of bps that crosscuts earlier normal and reverse faults that act as markers to allow metre scale patterns of horizontal displacement to be identified in mtds the studied bps always forms with a consistent top to the east sense of offset that corresponds with gravity driven downslope movement towards the depo centre of the basin bps frequently develops adjacent to competent detrital rich beds and forms discrete glide planes with little or no visible deformation in sediments on either margin although detachment folds are occasionally developed above the slip plane and confirm directions of easterly movement early downslope dipping normal faults that are cut by later bps planes results in older over younger stratigraphic relationships across the bps surface together with sawtooth patterns where multiple bps planes have developed conversely early upslope dipping normal faults that are cut by bps create younger over older stratigraphic relationships combined with missing section and staircase patterns where multiple bps planes exist as bps in sub horizontal sequences does not have a vertical component of displacement it may be examined in terms of horizontal heave bps increases heave in upslope dipping normal faults whereas it reduces heave in downslope dipping normal faults and may even become negative where sections are repeated across sawtooth profiles in addition bps increases heave in upslope dipping reverse thrust faults and reduces heave across downslope dipping backthrusts although individual bps planes may have limited displacement the net consequence of multiple planes of bps that form in the shallow subsurface is to distort patterns and estimates of extension and contraction across fault zones in mtds

deformation within an exposed salt wall recumbent folding and extrusion of evaporites in the dead sea basin abstract despite the enormous global interest in salt tectonics which is largely driven by its importance to hydrocarbon exploration direct field based studies of salt exposed at the earth s surface are rare however mount sedom located at the western side of the dead sea basin presents one such opportunity for detailed analysis of salt and the associated sedimentary and structural record of its movement the sedom salt wall is a 10 km 1 5 km n s trending ridge comprising a range of late miocene pliocene evaporites and clastics which have penetrated the overlying pleistocene clastic sequence the salt wall displays a moderate steep west dipping western margin and an overturned west dipping eastern flank the sedimentary record of passive wall growth includes sedimentary breccia horizons that locally truncate underlying beds and are interpreted to reflect sediments having been shed off the crest of the growing salt wall structurally the overturned eastern flank is marked by upturn within the overburden extending for 300 m from the salt wall deformation within the evaporites is characterised by ductile folding and boudinage while a 200 m thick clastic unit within the salt wall forms a tight recumbent fold traceable for 5 km along strike and associated with a 500 m wide inverted limb this overturned gently dipping limb is marked by ne directed folding and thrusting sedimentary injections and a remarkable attenuation of the underlying salt from 380 m to

bedding parallel lenticular soft sediment deformation structures a type of seismite in extensional settings abstract soft sediment deformation structures ssdss with bedding parallel lenticular morphology have been occasionally reported and called different names such as loop bedding or pillow bed however there is no understanding of the formative conditions that give rise to them versus other ssdss similar bedding parallel lenticular dolomite bodies tens of centimeters thick with quite variable lengths 30 cm 30 m occur across a large area 3000 km2 exclusively in the st louis member late vasean mississippian of the slade formation in east central kentucky usa field investigations indicate that the lenticular structures along with other associated ssdss represent a persistent deformed horizon that is correlative with and occurs symmetrically around the more intensely deformed big sinking bed which was previously interpreted as earthquake induced ssdss based on multiple lines of evidence the lenticular structures are interpreted to represent distal expressions of the same seismic event that generated the proximal big sinking bed the lenticular structures were subsequently dolomitized and their selective dolomitization is attributable to their brittle deformation during the earthquake which resulted in preferentially developed fracture porosity that allowed more efficient circulation of mg2 fluids throughout the lenticular structures petrographic and stable isotopic evidence also suggests that the selective dolomitization postdates the deformation probably related to a brine reflux system developed during the first marine transgression following subaerial exposure of the st louis carbonates based on comparative analysis with other global cases the bedding parallel lenticular structures are interpreted to represent a distinct type of ssds comparable to boudinage in tectonic deformation their formation reflects a situation in which seismically elevated pore fluid pressure is lower than vertical confining stress but higher than horizontal confining stress a prominent occurrence of lenticular type ssds is a potential indicator of syndepositional extensional stress regime which is testified by tectonic settings of all known cases including the kentucky dolomite bodies

soft sediment deformation structures interpreted as seismites in lacustrine sediments of the prebetic zone se spain and their potential use as indicators of earthquake magnitudes during the late miocene lacustrine formations of late miocene age in the prebetic area se spain show several types of deformational structures that are interpreted as seismites they are present in both marginal and deep lacustrine facies seismites formed in marginal lake environments comprise sand dikes pillows and intruded and fractured gravels in deep lacustrine facies the seismites are represented by pseudonodules mushroom like silts protruding into laminites mixed layers disturbed varved lamination and loop bedding the measured orientations of these structures are consistent with the orientations of the main faults limiting the basins showing that their origin is clearly related to the tectonic stress field that prevailed in the region during the late miocene the magnitudes of the earthquakes that deformed the sediments have been estimated after published data from both ancient and recent lake deposits accumulated in tectonic active regions elsewhere a rank of earthquake magnitudes with two end members i e the lowest magnitudes recorded by loop bedding in laminites and the highest magnitudes represented by intruded and fractured gravels is proposed

remote sensing lower thermosphere wind profiles using non specular meteor echoes 1 this article describes a new method of measuring wind velocity profiles between 93 km and 110 km altitude by tracking non specular meteor echoes as neutral winds transport the plasma trails this requires a large vhf radar with interferometric capability able to point nearly perpendicular to the geomagnetic field a small data sample from the jicamarca radio observatory allows the measurement of horizontal wind speeds and directions with a range resolution of a few hundred meters these observations show speeds reaching 150 m s and sometimes changing by as much as 100 m s over a 6 km altitude range at the best times these measurements can be made with only a few minutes of data with some refinement of the data collection and analysis techniques this technique should produce high resolution images of lower thermospheric winds as they change in both altitude and time

regional modeling of surface mass balance on the cook ice cap kerguelen islands 49 circ mathrm s 49 s 69 circ mathrm e 69 e we assess the ability of the regional circulation model mar to represent the recent negative surface mass balance smb observed over the kerguelen islands 49 circ hbox s 69 circ hbox e and evaluate the uncertainties in smb projections until the end of the century the mar model forced by era interim reanalysis shows a good agreement with meteorological observations at kerguelen particularly after slight adjustment of the forcing fields 10 humidity 0 8 circ hbox c all year round to improve precipitation occurrence and intensity the modeled smb and surface energy balance seb are also successfully evaluated with observations and spatial distributions are explained as being largely driven by the elevation gradient and by the strong west to east foehn effect occurring on the ice cap we select five general circulation models gcms from the coupled model intercomparison project phase 5 cmip5 by evaluating their ability to represent temperature and humidity in the southern mid latitudes over 1980 1999 with respect to era interim and use them to force the mar model these simulations fail to replicate smb observations even when outputs from the best cmip5 model access1 3 are used as forcing because all gcms fail in accurately reproducing the circulation changes observed at kerguelen since the mid 1970s global models chosen to represent extreme values of smb drivers also fail in producing extreme values of smb suggesting that more rigorous modeling of present and future circulation changes with gcms is still needed to accurately assess future changes of the cryosphere in this area