the triglav glacier south eastern alps slovenia volume estimation internal characterization and 2000 2013 temporal evolution by means of ground penetrating radar measurements it is well known that small glaciers of mid latitudes and especially those located at low altitude respond suddenly to climate changes both on local and global scale for this reason their monitoring as well as evaluation of their extension and volume is essential we present a ground penetrating radar gpr dataset acquired on september 23 and 24 2013 on the triglav glacier to identify layers with different characteristics snow firn ice debris within the glacier and to define the extension and volume of the actual ice computing integrated and interpolated 3d using the whole gpr dataset we estimate that at the moment of data acquisition the ice area was 3800 m2 and the ice volume 7400 m3 its average thickness was 1 95 m while its maximum thickness was slightly more than 5 m here we compare the results with a previous gpr survey acquired in 2000 a critical review of the historical data to find the general trend and to forecast a possible evolution is also presented between 2000 and 2013 we observed relevant changes in the internal distribution of the different units snow firn ice and the ice volume reduced from about 35 000 m3 to about 7400 m3 such result can be achieved only using multiple gpr surveys which allow not only to assess the volume occupied by a glacial body but also to image its internal structure and the actual ice volume in fact by applying one of the widely used empirical volume area relations to infer the geometrical parameters of the glacier a relevant underestimation of ice loss would be achieved

dansgaard oeschger and heinrich event imprints in alboran sea paleotemperatures past sea surface temperature sst evolution in the alboran sea western mediterranean during the last 50 000 years has been inferred from the study of c37 alkenones in international marine global change studies md952043 core this record has a time resolution of 200 years allowing the study of millennial scale and even shorter climatic changes the observed sst curve displays characteristic sequences of extremely rapid warming and cooling events along the glacial period comparison of this alboran record with 18o from greenland ice greenland ice sheet project 2 core shows a strong parallelism between these sst oscillations and the dansgaard oeschger events five prominent cooling episodes standing out in the sst profile are accompanied by an anomalous high abundance of neogloboquadrina pachyderma sinistral which is confined to the duration of these cold intervals these features and the isotopic record reflect drastic changes in the surface hydrography of the alboran sea in association with heinrich events hl 5

holocene sea level changes along the mediterranean coast of israel based on archaeological observations and numerical model local sea level curves reflect global eustatic changes regional isostatic adjustments of the crust to changing ice and ocean volumes and tectonically controlled crustal movements in this study we evaluate the relative contribution of each of these factors to the holocene sea level curve of the mediterranean coast of israel we use archaeological data as constraints on palaeo sea levels and we then compare the observational limits with isostatic models for sea level change across the region the isostatic model includes the contribution arising from the relative minor increase in ocean volumes for the past 6000 years due to residual melting of ice sheets the effect of the changing shape of the ocean basin the time dependence of shorelines as sealevel changes and the changing surface area occupied by ice sheets differences if significant between the observed and predicted change are interpreted as being of tectonic origin the archaeological observations and the model sea level curve along the mediterranean coast of israel were found to be generally consistent and any discrepancies lie within the uncertainties of both values our model predicted that 8000 years ago sea level at the israel coast was at about 213 5 2 m whereas the archaeological data place it at 216 5 1 m by 7000 bp the predicted level has risen to about 27 1 m consistent with the archaeological evidences according to both observations and predictions sea level was still lower than 2 3t o24 5 m at 6000 bp and remained below its present level until about 3000 2000 bp the comparison between the model sea level curve and the archaeological observations also enable to conclude that the average rate of vertical tectonic movement for the last 8000 years at the carmel coast israel has been less than 0 2 mm year q 2001 elsevier science b v all rights reserved

middle and late holocene sea levels along the israel mediterranean coast evidence from ancient water wells during the course of a study of historical water wells along the israeli shore which has been in progress since 1984 an innovative method for investigating sea level fluctuations was developed eighteen ancient water wells were re dug 14 by the author and four by archaeologists most of the re dug wells are found at archaeological sites located a very short distance inland from the present shoreline evidence of ancient ground water levels found in the wells directly reflects on historic eustatic sea level changes and the rate at which the end of the post glacial transgression advanced a critical question concerns the durability and life span of these wells as the true age is very important for the accurate reconstruction of a sea level curve the pre pottery neolithic well of atlit yam which is the oldest known well in the world ca 8000 yr old enabled the most accurate sea level reconstruction for early holocene times sea level rise during that period of the atlit yam site was of the order of 20 mm yr 1 at the beginning slowing to 6 8 mm yr 1 at the abandonment of this site at ca 7 5 ka bp when it was flooded by the advancing and rising sea after reaching its present level sea level fluctuations for the past 2 5 millennia were not greater than 1 5 to 2 m 1997 john wiley sons ltd

lacustrine flow divers side scan sonar hydrogeology water penetrating radar used to understand the location of a drowned person an unusual application of hydrological understanding to a police search is described the lacustrine search for a missing person provided reports of bottom water currents in the lake and contradictory indications from cadaver dogs a hydrological model of the area was developed using pre existing information from side scan sonar a desktop hydrogeological study and deployment of water penetrating radar wpr these provided a hydrological theory for the initial search involving subaqueous groundwater flow focused on an area of bedrock surrounded by sediment on the lake floor the work shows the value a hydrological explanation has to a police search operation equally to search and rescue with hindsight the desktop study should have preceded the search allowing better understanding of water conditions the ultimate reason for lacustrine flow in this location is still not proven but the hydrological model explained the problems encountered in the initial search

high resolution of glacial ice stratigraphy a ground penetrating radar study of pegasus runway mcmurdo station antarctica ground penetrating radar gpr has been used to detect areas of present or potential structural weakness beneath a 3 2 km snow covered ice runway on the ross ice shelf antarctica the bandwidths of the transmitted wavelets were centred near 500 mhz the data show many horizons up to tens of metres long and occurring to about a 9 m depth below which a brine intrusion limits penetration the horizons are interpreted as discrete scatterers because of their diffraction nature and loss of higher frequencies with depth the presence of porous ice or dispersed water is interpreted from wavelet phase the water may be associated with apparent deepening and fading of the brine horizon if the above interpretation is correct water occurs at depths to 3 5m and extends as much as 40 m horizontally which is greater and deeper than known previously at 3 5 m depth the water may be adsorbed on mineral particles rather than remain free migration of the diffractions with a single layer migration scheme shows all horizons above the brine layer to be small dielectric perturbations within the ice stacking and hilbert transformation of the data reveal slight folding along the length of the runway loss of high frequency amplitude in the wavelets suggests that higher frequency radar might improve resolution only in the top few metres

global climate instability reflected by eastern mediterranean marine records during the late holocene abstract extremely high sediment accumulation rates in the southeastern se mediterranean off israel make this region ideal for high resolution paleoceanographic reconstructions two cores were examined and foraminiferal oxygen and carbon isotope composition as well as physical and geochemical properties of the sediments were used to reconstruct the climatic and environmental changes of the se mediterranean basin during the late holocene 3 6 ka the 18o values of globigerinoides ruber suggest that the freshwater balance changed several times during this time interval humid phases took place between 3 5 3 0 ka bp and 1 7 1 0 ka bp the later was accompanied by enhanced preservation of terrestrial organic matter within the sediment ors event relatively more arid conditions prevailed in this area between 3 0 and 1 7 ka bp during the last millennia at ca 0 8 and 0 27 ka two climatic events occurred which are probably correlative to both the medieval warm period and the cooling global event known as the little ice age respectively a long term slight increase in planktonic foraminiferal 18o values occurs together with a gradual decrease in the 13c values of both g ruber and the benthic foraminifera uvigerina mediterranea this trend is associated with an increase in sedimentation rates ti al ratio magnetic susceptibility and color index of the sediments we suggest that this trend shown by various independent proxies seems to be related to the aridification process that started ca 7 0 ka in the mid low latitude desert belt and the se mediterranean region and continuous until the present the long term 13c decrease shown by surface and bottom water foraminifera reflects a gradual change in the 13c of the dissolved co2 of the entire se mediterranean water column this follows the global co2 rise in the late holocene as a result of the terrestrial biomass destruction during the aridification process moreover the gradual reduction of the vegetation cover in east africa led to an increased erratic flood related sediment flux via the nile river up to the present this is reflected by the general change in the local sediment composition at 3 6 ka the saharan eolian input reached 65 whereas at about 0 3 ka 70 of the se mediterranean sediment was composed of nile particulate matter

ground penetrating radar for assessing winter roads abstractsince its inception ground penetrating radar gpr has been a very effective method for examining ice structure the vast majority of early gpr use was focused on answering questions related to glaciology and ice sheets more recently as more and more activity occurs in arctic areas managing ice structures for a variety of applications has created new uses for gpr for the past 30 40 years gpr use for assessing transportation routes over lakes rivers and sea ice has been reported but only in the last decade has routine application occurred we have focused on the application of gpr for winter road safety explained the operational requirements discussed the current state of practice and illustrated modern gpr instrumentation based on widespread field observations we have provided information on the ice layer thickness variation and the variability on gpr ice bottom reflection combining extensive gpr and ice auger data provided insight into the variability of electromagnetic wave veloc

what can a sessile mollusk tell about neotectonics article i nfo dendropoma petraeum are fixed vermitids mollusk that colonize and construct abrasion platform rims along rocky shorelines these endemic mollusks are considered good relative sea level indicators in the eastern and the southern mediterranean due to their narrow habitat below the sea surface about 10 cm the observed relative sea level values recorded submerged uplifted or at present mean sea level reflect a superposition of eustatic isostatic tectonic and possibly local sedimentary instabilities the present study examines fossil dendropoma samples gathered along the levant coast from northern israel to eastern turkey conventional radiocarbon dates from turkey syria and partly in lebanon and 14 c accelerator mass spectrometer ams from lebanon and israel yields dendropoma ages ranging through late holocene a numerical model is used for calculating the change in sea level through the holocene as a function of glacio hydrology and isostasy of the eastern mediterranean space time dependent subtractions of the model values are used to eliminate the eustatic component of the relative sea level in order to obtain the tectonic component results show a general northward increase in tectonic uplift of the levantine coast with different rates in different tectonic segments this differential uplift corresponds well to the major tectonic segments comprising the levantine continental margin since the pleistocene from the carmel fault to the east anatolian fault hence these segments were still active during the last thousands years and even during the last hundreds years the general trend of northward increase in vertical displacement is predominantly dictated by the convergence between the sinai and arabian plates with anatolia and eurasia across the cyprus arc and zagros belt and the secondarily dictated by the northward increase in convergence component across the sinistral dead sea fault plate boundary

neotectonic activity in caesarea the mediterranean coast of central israel abstract evidence for neotectonic activity along the coast of the southern levant exists in the ancient harbor of caesarea in central israel where large herodian breakwaters are presently submerged 5 8 m below sealevel whereas other contemporary coastal installations in the same area remain at sealevel high resolution seismic reflection surveys on the very shallow continental shelf encountered a series of coast parallel faults that displace both the eolianite which crops out along the coastal zone and the submerged breakwaters the faults have 1 3 m of offsets downthrowing their seaward flank and leaving their landward flank stable we suggest that the subsidence of the ancient breakwaters was caused by neotectonic displacements on these faults and enhanced by solifluction records of historical earthquakes in the coastal levant region and archaeological evidence of faulting are compatible with the geophysical findings the neotectonic activity of the mediterranean coast of israel which is a consequence of the plio quaternary subsidence of the southeastern mediterranean basin has shaped the coast of the southern levant even during the past 2000 years

ancient wells and their geoarchaeological significance in detecting tectonics of the israel mediterranean coastline region eight ancient water wells representing the late bronze age to the crusades period ca 3100 700 b p have recently been excavated six by the authors and reopened at archaeological sites tels along the southern and central mediterranean coast of israel evidence of ancient freshwater levels directly reflects on possible neotectonics of the region and on eustatic changes of sea level there is substantial disagreement about the tectonic stability of the israel mediterranean coastal region during the past 3500 yr whether there was a large magnitude tectonic event one of the largest known for recent times during the period in discussion or whether the region was tectonically quiet we tested the instability hypothesis by using geoarchaeological data from the wells and found no evidence for significant tectonic deformation of the central and southern israel coast in the past 3100 yr the ancient water well method can with appropriate modifications be used all around the mediterranean and other coasts elsewhere in the world where ground water sea level relations are alike

the submerged pre pottery neolithic water well of atlit yam northern israel and its palaeoenvironmental implications the recent discovery of a vertical open shaft identified as a well of the pre pottery neolithic period was found in a large submerged village off the atlit promontory northern israel this well indicates that the exploitation of groundwater through wells commenced at the beginning of the eighth millennium bp or possibly earlier the well lies some 10 m below present sea level a few hundred metres off the carmel coast it is almost 1 5 m in diameter and some 5 7 m in depth which proves that the top of the well has been around 5 m above the contemporaneous sea level i e that sea level of the carmel coast was some 16 m below present sea level at c 7900 bp its fill provides evidence of the surrounding fauna and flora and the material culture of coastal neolithic communities the prevailing hydrological conditions provide important information on ancient sea levels at the end of the post last glaciation transgression rates of sea level rise at the period of the village occupation is estimated to

recent evolution of marmolada glacier dolomites italy by means of ground and airborne gpr surveys abstract a 10 year long evolution of ice thickness and volume of the marmolada glacier is presented quantitative measurements have been performed by using two different ground penetrating radar gpr datasets a ground based survey using two different ground coupled systems equipped with 100 mhz and 35 mhz antennas was performed in 2004 in 2015 the dataset was collected by using a helicopter borne step frequency gpr equipped with a 100 mhz antenna through a critical discussion of the two different methodologies we show how both approaches are useful to estimate the ice volume within a glacier as well as its morphological characteristics and changes with time even if datasets are acquired in different periods of the year the observed 2004 2014 ice volume reduction of the marmolada glacier is equal to about 30 while the area covered by ice decreased by about 22 the glacier is now splitted in several separated units it is very likely that the fragmentation of the marmolada glacier observed in the period 2004 2014 was accelerated due to irregular karst topography by applying the observed 2004 2014 ice melting trend for the future although the marmolada glacier might behave slightly differently compared to glaciers on non karstic terrains owing to dominant vertical subglacial drainage it will likely disappear by the year 2050 only few isolated very small and thin ice patches will eventually survive due to avalanche feeding and shading at the foot of the north facing cliffs

estimating winter ebullition bubble volume in lake ice using ground penetrating radar freshwater lakes are an important source of atmospheric methane ch4 however uncertainties associated with quantifying fluxes limit the accuracy of climate warming projections among emission pathways ebullition bubbling is the principal and most challenging to account for given its spatial and temporal patchiness when lakes freeze many methane rich bubbles escaping from lake bottom sediments are temporarily trapped by downward growing lake ice as bubble position is then seasonally fixed we postulate that it should be possible to locate bubbles using a geophysical approach sensitive to perturbations in the ice water interface and ice sheet structure generated by bubbles this study utilizes ground penetrating radar gpr to non invasively quantify the amount of ebullition gas present in lake ice to do this requires an appropriate petrophysical transformation that relates radar wave velocity and volumetric gas content we utilized laboratory experiments to show that electromagnetic models and vo

velocity analysis from common offset gpr data inversion theory and application to synthetic and real data we implemented a procedure to estimate the electromagnetic em velocity using common offset ground penetrating radar gpr data the technique is based on the inversion of reflection amplitudes to compute the series of reflection coefficients used to estimate the velocity in each interpreted layer the proposed method recursively calculates the incident angles at any interface taking into account the offset between antennas and needs as input in addition to the picked amplitudes values a reference amplitude for each analysed gpr trace and a velocity value for the first shallowest layer the latter two parameters can be estimated directly from the available data or can be better constrained by further dedicated gpr acquisitions or by additional direct measurements we critically evaluated the performances for both synthetic and real data acquired with different antenna frequencies and we demonstrated that the new method can be applied in several real situations despite the necessary approximations and simplifying hypotheses the velocity values calculated for each layer are consistent with direct information and with cross validations obtained considering profiles acquired using different antennas and various path directions tests of the method on synthetic and real data sets show that the errors in the calculated velocity fields are quite low and comparable with more demanding velocity analysis techniques the obtained em velocity field is crucial in many processing steps such as for example true amplitude recovery depth conversion and imaging and provide essential information to characterize the subsurface materials

sea level change and vertical land movements since the last two millennia along the coasts of southwestern turkey and israel abstract this paper provides new relative sea level data inferred from coastal archaeological sites located along the turkish coasts of the gulf of fethye 8 sites and israel between akziv and caesarea 5 sites the structures selected are those that for effective functioning can be accurately related to sea level at the time of their construction thus their positions with respect to present sea level provide a measure of the relative sea level change since their time of construction useful information was obtained from the investigated sites spanning an age range of 2 3 1 6 ka bp the inferred changes in relative sea level for the two areas are distinctly different from a rise of 2 41 to 4 50 m in turkey and from 0 to 0 18 m in israel sea level change is the combination of several processes including vertical tectonics glacio hydro isostatic signals associated with the last glacial cycle and changes in ocean volume for the israel section the present elevations of the mis 5 5 tyrrhenian terraces occur at a few meters above present sea level and vertical tectonic displacements are small data from gps and tide gauge measurements also indicate that any recent vertical movements are small the mis 5 5 shorelines are absent from the investigated section of the turkish coast consistent with crustal subsidence associated with the hellenic arc the isostatic signals for the israel section of the coast are also small ranging from 0 11 mm yr to 0 14 mm yr depending on site and earth model and the observed eustatic average sea level change corrected for this contribution is a rise of 13 5 2 6 cm during the past 2 ka this is attributed to the time integrated contribution to sea level from a combination of thermal expansion and other increases in ocean volume the observed sea levels from the turkish sites in contrast indicate a much greater rise of up to 2 2 mm yr since 2 3 ka bp occurring in a wide area between knidos and kekova the isostatic signal here is also one of a rising sea level of up to 1 mm yr and site and earth model dependent and the corrected tectonic rate of land subsidence is 1 48 mm yr this is the primary cause of dramatic relative sea level rise for this part of the coast

gpr study of pore water content and salinity in sand high resolution studies of hydrological problems of the near surface zone can be better accomplished by applying ground probing radar gpr and geoelectrical techniques the authors report on gpr measurements 500 and 900 mhz antennae which were carried out on a sorted clean sand both in the laboratory and at outdoor experimental sites the outdoor sites include a full scale model measuring 5 x 3 x 2 4 m sup 3 with three buried sand bodies saturated with water of various salinities studies investigate the capability of gpr to determine the pore water content and to estimate the salinity these parameters are important for quantifying and evaluating the water quality of vadose zones and aquifers the radar technique is increasingly applied in quantifying soil moisture but is still rarely used in studying the problems of water salinity and quality the reflection coefficient at interfaces is obtained from the amplitude spectrum in the frequency and time domains and is confirmed by 1d wavelet modelling in addition the gpr velocity to a target at a known depth is determined using techniques of two way traveltime cmp semblance analysis and fitting an asymptotic diffraction curve the results demonstrate that the reflection coefficient increases with increasing salinity of the moisture thesemore results may open up a new approach for applications in environmental problems and groundwater prospecting e g mapping and monitoring of contamination and evaluation of aquifer salinity especially in coastal areas with a time varying fresh water lens less

coastal neo tectonics of the mediterranean from tide gauge records abstract records from tide gauges in israel and egypt supplement the many geological and archeological investigations that have contributed information about relative sea level changes in the mediterranean region seven such records reveal changes during the past few decades that accord with prior inferences about land movements in this region emergence along the coast of israel and at alexandria and subsidence at the nile delta and the head of the gulf of suez twenty four other tide gauge records for the rest of the mediterranean region indicate more uniformity submergence of land or rise of sea level in the west but with greater movements of the land attributed to probable plate underthrusting in turkey and greece to volcanism near mount etna to deltaic compaction at izmir and to deltaic compaction coupled with water pumping at the po delta

cold based debris covered glaciers evaluating their potential as climate archives through studies of ground penetrating radar and surface morphology we describe the morphology and internal structure of mullins and friedman glaciers two cold based debris covered alpine glaciers that occur in neighboring valleys in the mcmurdo dry valleys antarctica both glaciers are overlain by a single dry supraglacial debris layer 8 75 cm thick each mantling debris layer is marked with near identical patterns of arcuate ridges and steps as well as corresponding changes in bulk grain size meter scale surface topography and thermal contraction crack polygons results from 24 km of ground penetrating radar data show that the ice within the uppermost 1 2 km of mullins and friedman glaciers is essentially free of englacial debris 1 by volume but thereafter is interspersed with bands of englacial debris each 3 m thick and dipping up glacier that intersect the ice surface at all major surface ridges and steps the similarity in number and pattern of englacial debris bands and corresponding surface ridges and steps across both glaciers along with model results and observations that call for negligible basal entrainment is best explained by episodic environmental change at valley headwalls our working hypothesis is that layers of englacial debris originate as supraglacial lags that form in ice accumulation areas during times of reduced net ice accumulation following renewed net ice accumulation these lags are subsequently buried by snow and ice flow englacially and intersect the ice surface to impart distinctive changes in the texture of supraglacial debris and topographic relief the implication is that the englacial structure and surface morphology of these cold based debris covered glaciers preserves a consistent record of climate and environmental change

1 4 ghz radar penetration and evidence of drainage structures in temperate ice black rapids glacier alaska u s a we have tested the ability of a 1 12 1 76 ghz bandwidth airborne frequency modulation continuous wave fm cw radar with an effective pulse duration of 3 ns to penetrate temperate ice of the ablation zone of black rapids glacier central alaska u s a we used high gain horn antennas to suppress clutter and tested over cold and nearly ideal surface conditions englacial horizons dipping to at least 60 m depth were found along three sections of one axial profile more narrow band 1 21 1 29 ghz low resolution 24 ns pulse duration profiles from a fourth section detected events at about 100 150 m depth comparative profiles recorded with a 100 mhz short pulse type radar reproduce the horizons of two of the sections and verify the penetration in all cases all horizons are composed of diffractions we interpret voids from the phase of the 100 mhz diffractions within one of the horizons the diffraction nature of the horizons the void interpretation and the proximity to a nearby and up glacier pothole field lead us to conclude that the horizons within two of the sections are meandering drainage channels a more complex branching structure with near surface horizons profiled within the third section much farther down glacier may also be a complex drainage system fed by near surface melting the fm cw signal to clutter noise ratios of some of the targets predict that they could be detected at 200 m depth in the 1 2 ghz range significant performance improvements at maximum vertical resolution could be achieved with higher gain antennas

flow dynamics in mid jurassic dikes and sills of the ferrar large igneous province and implications for long distance magma transport abstract magma flow paths in sill fed dikes of the ferrar large igneous province lip contrast with those predicted by classic models of dike transport in lips and magmatic rift settings we examine anisotropy of magnetic susceptibility ams flow paths in dike networks at terra cotta mountain and mt gran which intruded at paleodepths of 2 5 and 1 5 km these intrusions up to 30 m thick exhibit irregular interconnected dike sill geometries and adjoin larger sills 200 300 m thick at different stratigraphic levels both shallowly dipping and sub vertical magma flow components are interpreted from ams measurements across individual intrusions and often match macroscopic flow indicators and variations in dike attitudes flow paths suggest that intrusive patterns and magma flow directions depended on varying stress concentrations and rotations during dike and sill propagation whereas a regional extensional tectonic control was negligible or absent unlike giant dike swarms in lips elsewhere e g 1270 ma mackenzie lip dikes of the ferrar lip show no regionally consistent vertical or lateral flow patterns suggesting these intrusion were not responsible for long distance transport in the province in the absence of regionally significant colinear dike swarms or observed intrusions at crustal depths 4 km we suggest that long distance magma transport occurred in sills within beacon supergroup sedimentary rocks this interpretation is consistent with existing geochemical data and thermal constraints which support lateral magma flow for 3 500 km across the gondwana supercontinent before freezing

geophysical signature of a world war i tunnel like anomaly in the forni glacier punta linke italian alps global warming and the associated glacier retreat recently revealed the entrance to an ice rock tunnel at an altitude of 3600 m a s l in the uppermost portion of the forni glacier in the central italian alps the tunnel served as an entrance to an austro hungarian cableway station excavated in the rocks during the great war just behind the frontline a comprehensive geophysical survey based on seismic and ground penetrating radar profiling was then undertaken to map other possible world war i wwi remains still embedded in the ice the ice rock interface was reconstructed over the entire saddle and in the uppermost portion of the glacier a prominent linear reflector was surprisingly similar to the common response of buried pipes the reflector orientation almost longitudinal to the slope does not seem to be compatible with a glacial conduit or with other natural features numerical simulations of a series of possible targets constrained interpretation to a partly water filled rounded shape cavity the presence of a preserved wwi tunnel connecting mount vioz and punta linke could be considered a realistic hypothesis the forni glacier could be still considered polythermal and comprised of cold ice without basal sliding in its top portion

an imaging hf gpr using stationary antennas experimental validation over the antarctic ice sheet terrestrial and planetary imaging radar tapir is an innovative high frequency ground penetrating radar gpr developed in the frame of the martian netlander mission to probe the subsurface down to kilometric depths unlike most gprs tapir is able to image underground reflectors with stationary antennas in this paper after a brief presentation of the instrument we describe the method developed to interpret data collected during the radar of netlander in terre ade acutelie raneta field survey in antarctica this method consists of retrieving the direction of arrival of each detected echo through the measurement of five components of the electromagnetic field the three magnetic components and the horizontal components of the electric field thus both the range and the direction of each individual reflection or diffraction due to the ice bedrock interface are resolved we validated this method on finite difference time domain numerically simulated data for different subsurface configurations before applying it to raneta observations in particular the irregular topography of the bedrock in two sounding sites was revealed we discuss the accuracy of our results

airborne radar stratigraphy and electrical structure of temperate firn bagley ice field alaska u s a helicopter borne 135 mhz short pulse radar profiles of the bagley ice field southern alaska u s a have been analyzed to determine the nature of radio wave propagation through crevassed stratified wet and draining firn diffractions characterize the firn horizons along the trunk and reflections characterize those of overlying snow fields dynamic stacking was used to form and determine firn depths and unstacked diffraction analysis to determine firn layer properties refractive indices range from 4 1 to 4 5 for the near surface from 1 7 to 2 1 at about 13 17 m depth along the main trunk and to 2 6 to 58 m depth within a snowfield average trunk values correspond with volumetric water contents of about 0 09 which agree with values measured for other glaciers the analysis of the airborne recorded diffractions is confirmed by deriving the approximate refractive index of water from a supraglacial lake bottom diffraction the lack of snowfield diffractions suggests that crevassing and not firn structure caused the trunk diffractions the reasonable values of the indices imply that the diffractions originated from single points or edges orthogonal to the profile transect and they predict low interlayer transmission losses the snowfield penetration suggests that several hundred meters might be penetrated in uncrevassed accumulation zones with improved system design

beach deposits of mis 5e high sea stand as indicators for tectonic stability of the carmel coastal plain israel abstract ten beach deposits mainly beachrock on the carmel coastal plain northern israel are discussed six are reported for the first time the deposits are situated within or close to the following seasonal stream locally termed nahal channels nahal ahuza amiram ovadia galim megadim bir ibdawiya me arot and kebara the morphology and lithology of most of the deposits are similar their uppermost altitude varies from 0 to 9 m above the present sea level most of the deposits are composed mainly of fine quartz sand and marine mollusk shells carbonate cemented the dominant mollusk families are glycymerididae cardiidae and donacidae most of the beach deposits are situated between cemented aeolian sandstones locally termed kurkar layers on the carmel coast ridge in the nahal ahuza deposit a marine gastropod lentigo latus an index fossil for the mis 5e high sea stand in the mediterranean area was discovered according to lithology and chronostratigraphy the presence of lentigo latus th u aar and rtl dating and flint artifacts the beach deposits were related to the last interglacial maximum about 125 ka bp i e the mis 5e high sea stand these beach deposits are used to identify the palaeo sea levels and coastlines and to study the tectonics along the carmel coastal plain by comparing the elevations and characteristics of the beach deposits to known mis 5e deposits elsewhere and by analyzing archaeological data it is concluded that during the last 125 ka the maximum possible vertical displacement was less than 48 mm ka and the carmel coastal plain was relatively tectonically stable

phase structure of radar stratigraphic horizons within antarctic firn we have recorded reflection profiles of firn through large areas of west antarctica and part of the east antarctic plateau using 400 mhz short pulse radar the locations show accumulation rates that vary from well above to well below the vertical radar resolution most reflection horizons have extensive lateral continuity and are composed of distinctive wavelets with a consistent phase polarity sequence within their successive half cycles we modeled these waveforms and conclude that they arise from thin double layers of ice over hoar which is consistent with the standard model of firn stratification in addition we conclude that ice hoar layers are extensive throughout west antarctica and also present although more sparsely beneath the antarctic plateau

the role of gpr techniques in determining ice cave properties pena castil ice cave picos de europa the structure and ice content of ice caves are poorly understood ground penetrating radar gpr can provide useful insights but has only rarely been applied to ice caves this paper interprets gpr images radargrams in terms of internal structure stratification compaction thickness and volume of the ice block in the pena castil ice cave central massif of picos de europa northern spain providing the endokarst geometry of the ice cave in gpr data reflections eight radargrams were obtained by applying a shielded ground coupled antenna with a nominal frequency of 400 mhz although the radargrams do not depict the ice basal bedrock interface they suggest that the ice block is at least 54 m deep and similarly thick some curved reflection signatures suggest a potential vertical displacement in the block of ice and thus certain dynamics in the ice body other images show numerous interbedded clasts and thin sediment layers imaged as banded reflections in this particular cave a direct visual inspection of the ice stratigraphy is a difficult task but gpr provides clear reflectivity patterns of some of its internal features making gpr a suitable instrument for this and future studies to achieve a better and broader understanding of the internal behavior of ice caves