seismic potential of the dead sea fault in the northern gulf of aqaba elat new evidence from liquefaction seismic reflection and paleoseismic data abstract the cities of elat israel and neighboring aqaba jordan are major economic cultural and seaport centers they are located on the northern shore of the gulf of aqaba elat gae directly on the dead sea transform yet the precise location of the fault trace and its tectonic activity are lacking the interpretation of seismic reflection profiles across the gae beach and paleoseismic trench data located 2 2 km north of the shoreline provide evidence that the active offshore mapped avrona fault extends onland along the eastern side of the elat sabkha mudflat where three prominent fault strands crosscut the sedimentary fill mismatch of reflector geometry across the faults and flower structures indicate strike slip faulting with a normal slip component subsurface data from two trenching sites provide evidence for a minimum of two surface ruptures and two paleoliquefaction events faulting is constrained by radiocarbon dating for an event 1 between 897 and 992 ce and event 2 after 1294 ce we suggest that the historically documented 1068 ce and at least one later earthquake in 1458 or 1588 ce ruptured the elat sabkha site based on fault mapping we suggest a minimum value of m 6 6 for the 1068 ce earthquake whereas no surface rupture was observed for the 1212 ce historical earthquake fluidized strata radiocarbon dated to before 1269 1389 ce identified as paleoliquefaction may be attributed to it two liquefaction sand blows mapped in the trench likely formed after 1337 ce and before 1550 ce which possibly occurred at the same time as in the second faulting event our data suggest that no large event occurred along the avrona segment in the past 430 550 years given a 5 mm yr slip rate we conclude that a significant period of time passed since the last surface rupturing on the avrona fault increasing its seismic potential

morphological analysis of the lake lahontan shoreline and beachfront fault scarps pershing county nevada abstract with the diffusion equation representation of landform evolution providing reference calculations quantitative comparisons between profiles of the high stand of lake lahontan presented here and profiles of the lake bonneville shoreline scarps analyzed elsewhere reveal that the two sets of scarps are nearly identical morphologically when care is exercised in the selection of profiles the lahontan high stand scarps are remarkably reproducible from one profile to the next highly suggestive evidence that the processes that have shaped and changed the shape of these landforms are correspondingly regular slope angle differences of only 2 are both discernible and interpretable features of these late quaternary landforms cut in weakly consolidated alluvium at a level of uncertainty of no more than 50 per cent the mass diffusivity of the lahontan high stand is the same as the lake bonneville shoreline 1 1 gkg 1 gkg 1 m 2 ka this result suggests that much can be learned about the ages of late quaternary fault scarps cut in weakly consolidated alluvium throughout the basin and range province from their morphology alone the beachfront fault scarps themselves truncated by lake lahontan in our study area are morphologically only slightly older 15 to 18 ka bp than the lahontan high stand 12 ka bp

drainage system reorganization and late quaternary tectonic deformation along the southern dead sea transform the dead sea transform dst accounts for 105 km of left lateral slip between the arabian plate and the sinai subplate since the miocene paleoseismic studies along the arava valley segment of the dst suggest that late quaternary deformation has been primarily concentrated along the axis of the transform valley here we examine late quaternary changes in drainage system characteristics and attribute them to recent tectonic deformation in this region field based geomorphic mapping topographic cross sections and optically stimulated luminescence osl dating of fluvial deposits were used to map and date recent changes in the fluvial characteristics of catchments along the western margin of the southern arava our results reveal coeval migration of channels consistent with tectonically induced surface tilting caused by north south compressional deformation along the western margin of the transform valley osl dating indicates this tilting was initiated in the late pleistocene and continued at least into the mid holocene the late quaternary tectonic deformation along the southern arava segment of the dst is distributed across a wider zone than previously considered and extends out to the margins of the transform valley we associate the inferred wider deformation zone to possible changes in the geometry of motion along the dst

use of soils and colluvial deposits in analyzing tectonic events the southern arava rift israel abstract buried soils in colluvium units developed on downthrown fault blocks have been presumed to form during periods of tectonic quiescence this assumes however that all colluvial units on a fault scarp are tectonically induced particularly for a multiple event fault scarp to test this hypothesis we compared the colluvial stratigraphy and pattern of soil development on two non tectonic scarps terrace risers and a nearby multiple event fault scarp on the same alluvial fan surface both slopes developed under extremely and climatic conditions the colluvial stratigraphy and soil catenary relationship developed on terrace risers were found to be substantially different from those on the multiple event fault scarp the fault scarp colluvium contained several colluvial units separated by soils whereas only two colluvial units without buried soils were found on the terrace risers the colluvial units on the fault scarp were triangular in shape while those on the terrace riser were concave and overlapped up the slope cumulic soils indicating a continuous and low rate of deposition during pedogenesis were formed along the terrace riser in contrast buried soils indicating episodic deposition occurred on the downthrown block of the multiple event fault scarp accordingly the colluvial stratigraphy developed on the fault scarp can be viewed as a record of distinct tectonic events with no climatically controlled deposition the data indicate that soils and sedimentary stratigraphy can serve as useful indicators to distinguish terrace risers and single event fault scarps from multiple event fault scarps these indicators can be helpful in distinguishing phases of tectonic activity and in evaluating recurrence intervals on a multiple fault scarp

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

modification of wave cut and faulting controlled landforms from a casual observation that the form of degraded fault scarps resembles the error function this investigation proceeds through an elementary diffusion equation representation of landform evolution to the application of the resulting equations to the modern topography of scarplike landforms the morphologic observations can be analyzed either in the form of one or more cross strike elevation profiles or in the form of the slope offset plot a point plot of maximum scarp slope versus scarp offset working with either or both of these data representations for nine geologic structures which range in age from 3 to 400 ka b p and in offset from 1 to 50 m we apply analytical solutions for the vertical initial value scarp the vertical continuous offset scarp and the finite slope initial value scarp the model calculations are intrinsically ambiguous yielding as the final answer only the product t in the case of the initial value problem or the product a 1 in the case of the repeated faulting problem here t is the age of a single scarp forming event 2a is the vertical slip rate and is the mass diffusivity a single profile across three sea cliffs along the santa cruz california coast is analyzed as three separate initial value problems a reasonably constrained age for the sea cliff standing above the highway 1 platform returns 11 gkg 1 gkg 1 m2 ka with this we can date the two older sea cliffs in fact we do the converse age estimates for these two older sea cliffs based on a uniform rate of uplift both yield the same as for the lower sea cliff we treat a single profile of the raymond fault in pasadena san marino in terms of the repeated faulting problem for it the uplift rate of r crook and others yields 16 gkg the very substantial preexisting offset across the raymond fault must have been buried leveled some 230 ka b p when the modern topography began to form our analysis of the lake bonneville shoreline scarps reveals a dependence of t on 2a suggestive of nonlinear modification processes this appearance is treated with the finite slope initial value scarp model to determine 1 1 gkg for the lake bonneville shoreline scarps the suggestion of m n machette that approximately 100 000 year old meter high scarps are unobservable in weakly consolidated alluvial terranes of the basin and range and rio grande rift valley provinces can be formulated as 1 gkg the coincidence between this inequality and the lake bonneville shoreline is striking and it suggests that the value of 1 gkg may be generally applicable as a good first approximation to the modification of alluvial terranes within the semiarid regions of the western united states the lake bonneville shoreline is the basis for dating four sets of fault scarps in west central utah the drum mountains fault scarps can be modeled in several different circumstances but the most likely interpretation is that these fault scarps formed as the result of a single episode of normal faulting 3 6 to 5 7 ka b p the younger age is associated with quite low initial slope angles 25 the other three sets of fault scarps show no evidence for finite initial value slopes fault scarps along the eastern base of the fish springs range are very young 3 ka b p we estimate the age of fault scarps along the western flank of the oquirrh mountains to be 32 ka b p which meets the weak geologic constraint that they be older than the lake bonneville shoreline fault scarps along the northeastern margin of the sheeprock mountains are even older 53 ka b p an intriguing consequence of our single event analysis of these scarps is that an 11 5 m offset occurred in a single earthquake

true amplitude migration of 2d synthetic data true amplitude ta migration which is a kirchhoff type modified weighted diffraction stack recovers possibly complex angle dependent reflection coefficients which are important for amplitude versus offset avo inversion the method can be implemented using existing prestack or post stack kirchhoff migration and fast green s function computation programs here it is applied to synthetic single shot and constant offset seismic data that include post critical reflections complex reflection coefficients and caustics comparisons of the amplitudes of the ta migration image with theoretical reflection coefficients show that the possibly complex angle dependent reflection coefficients are correctly estimated

morphologic dating of fluvial terrace scarps and fault scarps near west yellowstone montana analysis of fault and fluvial terrace scarps in the west yellowstone basin south of hebgen lake montana indicates that during degradation the gradient of the scarp face and the curvatures of the basal concavity and crestal convexity of the scarp face decrease become more rounded with time the pattern of degradation is identical with that predicted by a simple analytical model for degradation by creep in which the change in elevation at a point on a hillslope is proportional to the curvature of the profile at that point the model therefore provides the basis for morphologic dating a technique for determining the age of a scarp by the extent to which its initial morphology has been degraded in order to date a scarp the coefficient of proportionality c must be known the technique is probably not suitable for use on hillslopes degraded by processes other than creep both the potential and the limitations of morphologic dating are demonstrated via measurements of a sequence of terrace scarps along the madison river the calculated relative ages are in agreement with the known relative ages despite the fact that the gradient of the youngest scarp is significantly less than that of the older scarps to calculate an absolute morphologic age c must be derived from analysis of a scarp of known age having the same aspect must be underlain by the same material and must be within the same climatic zone as the scarp to be dated in the west yellowstone basin a value of c 2 00 0 38 10 3 m 2 yr was calculated from a minimum date of 7100 50 yr b p determined by radiocarbon dating for one of the terrace scarps scarps formed by normal faulting in the west yellowstone basin are much more difficult to date than are terrace scarps because of the possible complexity of their initial morphology fault scarps formed during the 1959 yellowstone earthquake commonly consist of an assemblage of two or more smaller scarps or are superimposed on preexisting scarps formed by one or more previous faulting events by using a selective sampling procedure however one can screen out these fault scarps in this way it was possible to determine an age of 2 800 1 100 yr for a pre 1959 fault scarp in the west yellowstone basin because the fault and terrace scarps in the west yellowstone area do not vary significantly in height the morphologic dating technique proposed earlier by nash 1980a cannot be applied to them the substantially modified procedure developed for the present study does not require a wide range of heights for each scarp to be dated it can be performed using a relatively small number of scarp profiles if c is known it is easy to use and when used with considerable care it is reasonably accurate 36 59 in this study it is potentially applicable to scarps in other areas

ages estimated from a diffusion equation model for scarp degradation the diffusion equation derived from the continuity equation for hillslopes is applied to scarp erosion in unconsolidated materials solutions to this equation allow direct calculation of the product of the rate coefficient and the age of the scarp from measurements of scarp morphology where the rate coefficient can be estimated or can be derived from scarps of known age this method allows direct calculation of unknown ages of scarps

stages and rate of the gravel shattering process by salts in desert reg soils abstract gravel shattering by salts is a common process in gravelly young to mature desert reg soils the shattered gravel is found on the surface and in the b and c horizons down to a maximum depth of 50 cm field studies on the process of salt weathering in deserts are scarce therefore the objectives of this study are to present the stages of development of the gravel shattering process by salts in desert reg soils and to discuss factors influencing the rate of development under natural conditions prevailing in the negev desert the studied reg soils were developed on two alluvial fan chronosequences in the negev desert the fan of nahal ze elim and the fan of nahal shehoret the development of the shattering process can be divided into five stages a e based on chemical physical and micromorphological features of the reg soils stages a d very young yo young reg soils represent the early holocene to the present some 14 000 years salinity values are between 0 27 16 mmho cm and the percentage of the shattered gravel is between 20 and 70 the shattered gravel however still maintains its original shape stage e mature reg soil represents the middle pleistocene to early holocene or 500 000 years salinity values at this stage reach 62 mmho cm although part of the gravel does not keep its original shape and starts to disperse in the profile the percentage of shattered gravel is only 75 80 it was found that the process of salt shattering in reg soils does not depend on concentrations or mineralogy of the salts but on the micro environmental conditions of the soil profile the process requires extreme and rapid variations of temperatures and moisture conditions such as found close to the soil surface to cause salt crystallization in a confined system with time the sealing of the soil surface through the development of desert pavement and a gravel free b horizon results in a change in the soil micro environment this change impedes the process irrespective of the amounts concentrations and types of salt minerals which exist in the profile the fact that in extreme arid regions the gravel shattering process develops primarily close to the reg soil surface suggests that it can be used to identify buried reg soils and to reconstruct climatic and micro environmental conditions of paleosols

estimating the ages of fault scarps in the arava israel abstract systematic age estimations for the numerous fault scarps that rupture the alluvial fans in the southern arava valley israel are rare or nonexistent here we estimate the morphologic ages of several of these faults by the fault scarp degradation method and show that the ages agree well with ages estimated by the independent earlier soil geomorphic studies the values we use for the coefficient of diffusion for the fault scarp degradation process are calibrated by a few numerical ages these ages were determined by the infrared stimulated luminescence irsl method on one of the fault scarps and are the only numerical ages in the region the morphologic ages are all in a correct stratigraphic order and in agreement with field stratigraphic relationships determined by earlier studies they indicate that the studied fault scarps range in age from the latest pleistocene to very recent times the most recent fault scarps which were analyzed are less than 2000 years old and perhaps much younger they indicate that at least two earthquakes with magnitude 6 5 have affected southern israel and jordan during that period it is emphasized that so far we have studied only a limited number of fault scarps and therefore the number of large earthquakes during the last one to two millennia is a minimum

dating quaternary fault scarps formed in alluvium using morphologic parameters abstract ages of fault scarps as well as those other types of transport limited slopes can be estimated by comparing their morphology with the morphology of scarps of known age age estimates are derived by fitting the scarp profiles to synthetic profiles generated using a diffusion equation or alternatively by classification using a linear discriminant function the usefulness of morphology derived age estimates depends on the relative importance of non age related morphologic variation data from more than 200 scarp profiles demonstrate that morphologic variation not related to scarp age can introduce significant uncertainties into morphology derived age estimates

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

late glacial mountain glacier culmination in arctic norway prior to the younger dryas abstract climate changes during the late glacial period lg 15 11 ka as recorded in greenland and antarctic ice cores show a bipolar pattern between 14 5 ka and 13 ka ago the northern latitudes experienced the bolling allerod ba warm period while southern records feature the antarctic cold reversal acr between 12 9 ka and 11 7 ka ago the north was under the younger dryas yd cold spell while southern latitude temperature rose in parallel to atmospheric co2 concentrations while the southern hemisphere pattern is well documented in mountain glacier moraine records from new zealand and patagonia in northern mid latitudes and the arctic the lg glacier culmination has been connected to the yd stadial apparently confirming the bipolar pattern we present a geomorphic map of mountain glaciers in arctic norway a cosmogenic nuclide chronology from 71 moraine boulders from the lg and the holocene and first order glacier modeling experiments the model and dating results show that the studied mountain glaciers are most sensitive to summer temperature change that their response to those changes is highly correlated to a wider region and that these mountain glaciers in arctic norway reached their maximum lg extent about 14 ka ago prior to the yd following considerable retreat through the first part of the yd glaciers re stabilized in the mid yd and showed slower oscillatory retreat through the latter part of the yd we compare this glacier pattern to updated earlier glacier records in the wider arctic and north atlantic region and propose a pattern of coherent glacier response to climate changes during this interval the lg results from arctic glaciers show consistency to the glacier record from new zealand and patagonia this first order interhemispheric coherency of lg mountain glacier fluctuations driven mainly by summer temperature would support the view that the bipolar seesaw was primarily a northern winter phenomenon during the lg period and the yd in particular more similar experiments need to be performed to further test this scenario

indicators of faulting events and periods of quiescence in desert alluvial fans the main objective of the present paper is to present an integrated approach to the study of faulting stages in coarse alluvial deposits the study site is the alluvial fan of nahal shehoret presently under an extremely arid regime the exposure of fault scarps on the fan surfaces enables the identification of several geomorphic indicators employed in analysing and separating faulting events and periods of quiescence a the nature of fault scarp topography b soil catenary development on fault scarps c buried paleosols in alluvial deposits d colluvial bodies e rotated clasts along fault planes these indicators enable us to determine at all sites studied the total amount of displacement to separate faulting events and the amount of their displacement per event and to evaluate scarp stability and the duration of periods of tectonic quiescence

the evolution of holocene reg gravelly soils in deserts abstract reg soil is an aridisol developed upon a stable alluvial surface composed of sand to coarse gravel the objectives of the present study were 1 to examine the initial evolution of reg soil properties with time 2 to assess and explain the rates of development of different properties 3 to establish the suitability of different soil properties for relative age dating the time dependent soil properties examined were 1 mechanical weathering of surficial rocks and desert pavement evolution 2 chemical and biological weathering of surficial rocks 3 the thickness of soil profiles and soil horizons 4 soil texture in the different horizons 5 salts and gypsum distribution and concentration in different soil horizons 6 degree of mechanical weathering of gravel in c horizons fifteen successive surfaces of the nahal wadi ze elim sequence of alluvial fans were selected for study dead sea region israel under an extremely arid climate the sequence is of holocene age 14 000 years b p to recent the main conclusions are 1 reg soils develop rather fast in several 10 3 years since their initiation however the various soil properties developed at different rates 2 the rates of change of three soil properties decrease with time these are the texture in different horizons change in added airborne and rain washed dust salinity within the soil profile change in added salts and gypsum and the amount of mechanically shattered rocks 3 soil thickness is established rather rapidly young and older holocene soil have practically the same depth surficial weathering rates appear to remain fairly constant with time 4 in coarse gravel the evolution of reg soils is dependent on added fines and salts of airborne origin and the resultant changing hydrologic regime in the soil profile the run off infiltration ratio changes as more fines and salts are added to the soil profile and as desert pavement develops 5 surficial features and fine clay in the soil profile may be used for approximate dating of otherwise undatable holocene alluvial surfaces salts and gypsum content should be cautiously used in a rather general way

effect of height and orientation microclimate on geomorphic degradation rates and processes late glacial terrace scarps in central idaho terrace scarps can serve as a nearly ideal natural laboratory for the study of the evolution of slopes this paper examines the effects of scarp size height and orientation microclimate by keeping constant variables such as age lithology and regional climate if a scarp degrades as a closed system and downslope movement is directly proportional to surface gradient the evolution of the scarp is modeled by the diffusion equation for a group of scarps of same age and known starting angle the diffusion equation model predicts the relation between maximum scarp angle and scarp height h late pleistocene terrace scarps now as steep as 33 25 as well as measured angles of repose for sand and gravel require a starting angle as steep as 33 5 for latest pleistocene idaho and utah scarps as h increases is gentler more degraded than modeled by the diffusion equation with a constant rate coefficient the degradation rate coefficient c increases tenfold with scarp height it should not change with scarp height if downslope movement is solely determined by surface gradient to the first power soil wash appears to be responsible for this departure from the diffusion equation model for transport rate by soil wash is a function of scarp size height south facing scarps are less vegetated and more degraded than north facing scarps for scarps 2 m high the degradation rate c on s facing scarps is 2 times that on n facing scarps for 10 m scarps it is 5 times the observed dependence of the rate coefficient c on scarp height can be removed by normalizing c to values for west facing scarps of the same height the residual c values calculated by this method correlate well with differences in incident solar radiation resulting from the different scarp orientations and maximum gradients this correlation demonstrates the importance of orientation on slope processes and their rates through the differences in freeze thaw cycles soil moisture and vegetative cover scarp morphology may be used to estimate age if one accounts for the effects of climate and for scarp height orientation and lithology for example using the dated bonneville shoreline scarps for calibration and comparing only scarps of equal height we estimate the drum mountains fault scarps to be 9 000 yr old this age is about twice that produced by previous diffusion equation calculations that have not accounted for the height as we have here but it is the same as independent geologic estimates of their age

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

scarp degraded by linear diffusion inverse solution for age under the assumption that landforms unaffected by drainage channels are degraded according to the linear diffusion equation a procedure is developed to invert a scarp profile to find its diffusion age diffusion age having dimension length 2 is the product of diffusivity times chronological age the second moment of scarp slope grows linearly with age this fact together with an assumption about initial scarp shape allows the inverse determination of diffusion age age found assuming a vertical initial scarp is termed apparent age any nonvertical initial scarp profile has a nonzero initial apparent age true diffusion age differs from apparent age by a fraction of scarp offset squared the inverse procedure applied to synthetic data yields the following rules of thumb evidence of initial scarp shape has been lost when apparent age reaches twice its initial value if a scarp is formed by two events the inversion gives their offset weighted mean age with an error that is a fraction of offset squared a scarp that appears to have been formed by one event may have been formed by two with an interval between them as large as apparent age after scarps of two fault traces have diffused to appear as one the error in inferred age may be as large as half the apparent age variation of apparent age along strike would indicate multiple fault traces the simplicity of scarp profile measurement and this inversion makes profile analysis attractive if linearity of the flow law time for a free face to be reduced to the angle of repose and variation of diffusivity with climate and material could be established profile analysis would become a reliable dating technique

morphology of the latest quaternary surface faulting in the gulf of elat region eastern sinai abstract a variety of morphotectonic features bear evidence of neotectonic activity along the gulf of elat these include stepped topography deflected channels fault line grabens sag pond depressions backtilted fan segments faulted gravel bars and debris flow deposits the age of the fault scarps is estimated on the basis of the extent of dissection the amount of rounding of the crest of the scarps the scarp gradient the stage of clast weathering the intensity of the micro relief and the stage of soil and desert pavement development the field data are interpreted and related to the geomorphic time curves suggested by wallace by bucknam and anderson and by nash and the seismic hazard implications are discussed some criteria suggest a recent age with 10 000 yrs b p as a frequently recurrent estimate from the data it is concluded that the gulf of elat has definitely been tectonically highly active during the holocene

andean growth and monsoon winds drive landscape evolution at sw margin of south america abstract in the atacama desert the driest place on earth located at the subduction margin of the andes the landscape evolves very slowly and changes in tectonic or erosion processes remain for a long time in the memory of topography at latitude 19 30 s a threshold between exoreic and endoreic drainage regimes is clearly associated with the latitudinal gradient imposed by the modern monsoon carrying humidity from the atlantic and disposed obliquely over catchments draining the andes to the pacific we summarize the geomorphic geological and climatic data in the threshold area we then use these data to constrain numerical experiments of drainage evolution data and experimental results are consistent with the development of a flat low energy morphology close to sea level interrupted at 10 ma by tectonic uplift prevailing to the present suggesting trench ward relief growth by incorporation of the coastal atacama region to the andes mountain belt