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

rapid entrenchment of stream profiles in the salt caves of mount sedom israel rock salt is approximately 1000 times more soluble than limestone and thus displays high rates of geomorphic evolution cave stream channel profiles and downcutting rates were studied in the mount sedom salt diapir dead sea rift valley israel although the area is very arid mean annual rainfall 50 mm the diapir contains extensive karst systems of holocene age in the standard cave profile a vertical shaft at the upstream end diverts water from a surface channel in anhydrite or clastic cap rocks into the subsurface route in the salt mass balance calculations in a sample cave passage yielded downcutting rates of 0 2 mm s 1 during peak flood conditions or about eight orders of magnitude higher than reported rates in any limestone cave streams however in the arid climate of mount sedom floods have a low recurrence interval with the consequence that long term mean downcutting rates are lower an average rate of 8 8 mm a 1 was measured for the period 1986 1991 in the same sample passage quite independently long term mean rates of 6 2mm a 1 are deduced from 14c ages of driftwood found in upper levels of 12 cave passages these are at least three orders of magnitude higher than rates established for limestone caves salt cave passages develop in two main stages 1 an early stage characterized by high downcutting rates into the rock salt bed and steep passage gradients 2 a mature stage characterized by lower downcutting rates with establishment of a subhorizontal stream bed armoured with alluvial detritus in this mature stage downcutting rates are controlled by the uplift rate of the mount sedom diapir and changes of the level of the dead sea passages may also aggrade these fast developing salt stream channels may serve as full scale models for slower developing systems such as limestone canyons

petrography and reservoir physics ii relating thin section porosity to capillary pressure the association between pore types and throat size porosity in reservoir rocks is configured into a few types of pores whose size and shape are controlled by depositional fabric and postdepositional processes the size shape and abundance of each pore type can be objectively determined from thin section using image analysis and pattern recognition procedures each pore type tends to be associated with a limited range of throat sizes the association between pore type and throat size can be determined using regression procedures linking pore type data obtained from thin section with capillary pressure data to do so a set of samples is required wherein the association between pore type and throat size is fixed but where pore type proportions vary between samples this condition is met by a sample suite representing res rvoir facies from a single core or in many cases from a single field the relationship between pore type and throat size is an effective means to relate reservoirs in terms of the efficiency of the porous microstructure to multiphase flow parameters derived from the relationship can be used to construct accurate physical models that subdivide physical response in terms of the contributions of each pore type

late pleistocene rise of the sedom diapir on the backdrop of water level fluctuations of lake lisan dead sea basin abstract during the last glacial between 70 and 15 kyr b p large parts of the dead sea rift were inundated by lake lisan we use the established history of lake lisan water level fluctuations as a tool for determining the rates and styles of the salt tectonic uplift of the sedom salt diapir our reconstruction is based on new accurate mc icpms u th ages of lake lisan deposits overlying the top of mount sedom the surface expression of the sedom diapir these sediments range in age between 46 4 and 15 5 kyr b p comparison of the present elevations of the studied lisan sediments to the lake lisan level curve indicates that these sediments were uplifted to their present elevations due to the diapiric rise of mount sedom during the late pleistocene lisan sediments older than 46 4 kyr b p were not found yet on mount sedom suggesting that it was exposed prior to that time we correlate the exposure phase of mount sedom with the lowest stand of lake lisan between 48 and 43 kyr b p during which previously deposited sediments were eroded the age of the top of the lisan formation on mount sedom is 15 5 kyr b p and it has been uplifted by 75 m since then

a new methodological approach to assess the stability of discontinuous rocky cliffs using in situ surveys supported by uav based techniques and 3 d finite element model a case study abstract this paper aims to present a new methodological approach for the stability assessment of coastal cliffs constituted of discontinuous rock masses the method entails in situ specific geostructural and geomechanical surveys three dimensional uav based photogrammetric structural models laboratory geotechnical tests and two and three dimensional finite element analysis fem the application of the method to a case study is then presented and discussed it regards a 600 m long sea rocky cliff located at sant andrea melendugno south of apulia se italy and faced to the southern adriatic sea here the cliff is made up of an about 15 m thick sequence of laminate calcisiltites alternate with bioturbated calcarenites belonging to the uggiano la chiesa fm middle upper pliocene the structural discontinuities detected with photogrammetry techniques were compared and validated with those derived from conventional in situ survey methods later on the paper discusses assumptions and results of two and three dimensional finite element models developed to investigate the potential failure mechanisms of the sea cliff accounting for pre existing weak planes or discontinuities with unfavourable orientation the failure mechanisms obtained by both fem analysis agree well with those typically observed in the study area

orthogonal microscopy image acquisition analysis technique for rock sections in polarizer angle domain abstract the microscopic identification of rock sections is one of the most basic research methods of petromineralogy which is important to the research of mineral composition pore throat characteristics interstitial filling etc the traditional manual identification method was time consuming and also burdened with errors due to the subjective nature of human judgment which can bring some uncertainties to the further results therefore this paper proposes a technique for image acquisition and analysis of rock sections based on sequential images of rock sections in angle domain under polarizing microscope the analysis includes the following three steps firstly based on the multi angles extinction feature of rock section the direction adaptive correlation coefficient method was used to characterize the edge of the rock sections and segment the rock grains a series of parameters including grain size roundness convexity flatness and roughness were also extracted to characterize the morphological features of rock grains quantitatively secondly the variation characteristics of multi channel parameters rgb and gray channel with angle domain were analyzed for different minerals and then the mineral composition was accurately identified on the basis of grain segmentation the pore structures including intergranular pores dissolved pores and throat were extracted and the parameters of pore structure were also obtained finally the distribution of the interstitials was characterized based on the change of the extinction characteristics of the interstitials in the pores image analysis technique based on rock sections with polarizing microscope provides an effective and convenient method for grain segmentation mineral composition classification pore identification and interstitial analysis

bimodal porosity in oolitic reservoir effect on productivity and log response rodessa limestone lower cretaceous east texas basin running duke field houston county texas is on a small domal structure in the east texas basin the field currently consists of five gas wells producing from the lower cretaceous rodessa limestone seven additional gas completions have been plugged the rodessa yields water free gas production from zones with water saturations in excess of 60 porosity ranges from 7 to 14 the depositional model depicted for the rodessa in this field starts with the development of an active organic buildup this was successively overlain by ooid skeletal peloid lime sands lagoonal lime muds and subsequently by anhydrite and shale six lithofacies based on core study were recognized for the rodessa each facies has a uniform diagenetic history in the field making porosity development predictable for each facies the one grainstone facies forms the reservoir in the field and has two distinct diagenetic sequences one consists of a marine isopachous cement followed by a later partial infilling of pore space by sparry calcite the resulting intergranular porosity has a unimodal pore size distribution in the other sequence a discontinuous meteoric phreatic cement is followed by sporadic patches of sparry cement the resulting pore size distribution is bimodal with intergranular macropores and intercrystalline micropores within peloids and micritized ooids water free gas production is limited to the rock with the bimodal pore system macropores hold movable gas and micropores hold bound water within grains where core data are not available cross plotting techniques using geophysical logs are suggested as methods for separating the productive from the nonproductive grainstone

physico mechanical properties and durability performance of natural building and decorative carbonate stones from cyprus natural stone was the primary building material in cyprus in the past nowadays its use is mostly confined to decorative purposes and restoration projects this study represents the first thorough and systematic investigation of the characteristics of local carbonate stone the variety of the results recorded highlights the complexity of this natural geomaterial and hence the particular attention needed before selecting the appropriate lithotype in construction practice stones coming from the same geological formation exhibit significant variations in their physico mechanical properties the materials durability against salt crystallization is explained with reference to their pore structure and flexural strength revealing that in many cases small differences may have a significant impact on stone performance the study also investigates the use of novel microdestructive techniques in the prediction of the mechanical properties of the stones under study these techniques can be especially useful in the characterization of monumental stone where sampling is limited or when in situ characterization of stone is required natural stone has been extensively used throughout the history of mankind both for building and decorative purposes even though it is considered one of the most durable traditional geomaterials existing stone structures and monuments often show evidence of weathering and decay stress inflicted during use and by local climate are the major contributing factors to the degradation of building stone the precise response of individual stone samples is highly variable this is attributed to the complex nature and physico mechanical behaviour of natural stone understanding the materials performance under loading or different environmental conditions is therefore considered of crucial importance in ensuring the sustainable use of stone in construction practice

a new type of active margin the convergent extensional margin as exemplified by the middle america trench off guatemala the results of dsdp legs 67 and 84 during which a transect of holes was drilled across the middle america trench off guatemala show no accretion at the front of that subduction zone since early eocene time the tectonic evolution of the trench includes extensional structure on the landward as well as the seaward trench slopes the guatemalan margin is proposed as the model of a new type of active margin the convergent extensional active margin ce margin

empirical prediction of porosity and permeability in sandstones current efforts to predict porosity and permeability in sandstones prior to drilling are focused on empirical and process oriented models empirical predictions are based on the correlation between porosity and permeability and a limited number of parameters obtained from calibration data sets or estimated from appropriate geologic models of these parameters the most important are detrital composition grain size sorting and temperature history or pressure history or both despite its limitations the empirical approach provides accurate predrill predictions of reservoir quality in many sandstones containing not only primary but also secondary porosity and permeability predictions of the average porosity and permeability of target sandstones are arbitrarily defined h re as accurate if they fall within 2 porosity of the mean measured porosity and within the same order of magnitude as the mean measured permeability in a sample population representing the interval of interest the effectiveness of the empirical predictive approach is illustrated by case studies from the taranaki basin new zealand and yacheng field people s republic of china these studies indicate that empirical predictions are basin specific or even play specific and require at least some understanding of fundamental processes affecting reservoir quality of a given sandstone target process oriented approaches attempting to model the effect of diagenesis on reservoir quality are hampered by inadequate quantitative understanding of the processes responsible for preserving primary porosity and generating secondary porosity and permeability until adequate quantification of the sandstone diagenesis processes is achieved empirical models have a distinct advantage over process oriented models in providing reliable predictions of reservoir quality in many sandstone intervals

the cave of the letters sediments indication of an early phase of the dead sea depression abstract the highest aquatic sediments along the shoulders of the dead sea depression have been found in the cave of the letters nahal hever israel the cave has acted as a sediment trap preserving autogenic dolomite and detritic deposits the dolomitic sediment may correlate with late miocene dolomites within the rift valley the morphostratigraphic setting of the sediment implies deposition within an early topographic low that existed in the dead sea region since 10 to 7 ma

formation and dating of a salt pillar in mount sedom diapir israel the formation of a 20 m high salt pillar in mount sedom dead sea area was analyzed and dated and these results were complemented by measurement of present uplift rate because the pillar is a part of the actively rising sedom diapir contrary to earlier assumptions which stated that the salt pillar was formed by direct rainfall the observed solutional notches and morphology of the neighboring chasm indicate that the salt pillar is due to a karstic cave that collapsed the uppermost part of the cave still carried an underground ephemeral stream 4000 yr ago as indicated by six 14c dates of wood washed into the highest cave level the sudden collapse that left the isolated salt pillar was probably triggered by a catastrophic earthquake the measured uplift rate 9 3 3 5 mm yr shows that when the pillar formed it was much closer to the base of mount sedom

a three dimensional back analysis of the collapse of an underground cavity in soft rocks abstract the assessment of stability of man made underground caves excavated in the past and later on abandoned represents a serious challenge for land and urban planning operations especially for the areas of possible interaction of the caves with overlying structures and infrastructures several areas of southern italy are characterized by the presence of abandoned underground quarries for the extraction of soft calcarenite rocks which now threatens the overlying environment due to the risk of collapse and the consequent generation of sinkholes this work presents a back analysis of a sinkhole occurred in 2011 in the town of marsala caused by the collapse of an underground quarry as a representative case study of these phenomena based on the available geometrical and geological dataset as well as the field observations of the phenomenon in this article the assumptions and the results about the genesis of the 2011 sinkhole as derived from a three dimensional finite element back analysis aimed at reconstructing the stress strain evolution that brought to the ground failure collapse is discussed in particular the 3 d numerical analyses have been performed in order to identify the factors responsible of the genetic mechanism of the sinkhole the finite element analysis has been carried out by accounting for the geotechnical characterization of the marsala calcarenites derived from both specific laboratory tests performed on samples taken from the site and literature data available on the same rock material the numerical results have been then validated by means of the comparison with field observations and also compared with those achieved through a 2 d model of the same case study

diagenetic processes influencing porosity in sandstones from the triassic buntsandstein of the iberian range spain abstract sandstones of the triassic buntsandstein of spain were studied in an attempt to quantify effects of diagenetic processes such as compaction cementation and leaching on reservoir properties samples were taken from shell well siguenza 44 3 some 110 km northeast of madrid drilled on the siguenza high in the iberian range the sandstones are arkoses to sublitharenites of a typical triassic redbed facies characteristic of the whole region the present day depth of the base buntsandstein is 538 m whilst a maximum burial depth of ca 2600 m was estimated from vitrinite reflectance 0 94 to 1 14 kaolinite temperature 76 c and illite crystallinity kuebler index 4 9 from an estimated average initial porosity of 38 porosity was reduced to the present value of 13 the strongest process to reduce porosity was found to be mechanical compaction causing a loss of 15 followed by chemical compaction pressure solution with a loss of about 6 the cement 11 4 r v apparently reduced the initial porosity by about only 5 early carbonate and sulphate cements are interpreted to have stabili sed the rock framework working against mechanical compaction and pressure solution this is supported by an increase in sutured grain contacts where early cements are absent or rare the later quartz cement interpreted to be largely the product from pressure solution has reduced porosity in a ratio of 0 5 1 this suggests that compaction continued after the formation of the late quartz cement although leaching was observed especially in feldspar grains clay and k feldspar neomorphosis is interpreted to have counteracted the formation of substantial secondary porosity permeability in the buntsandstein is generally low average 17 4 md and has been strongly affected by the alteration of feldspars to clay causing a wide range of permeability from 0 11 to 73 0 md

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

petrographic quantification of brecciated rocks by image analysis application to the interpretation of elastic wave velocities abstract this paper presents a new procedure to quantify the petrology of materials with complex and heterogenic rock fabric features the classical methodologies for petrographic quantification by image analysis are not appropriate for this kind of rock due to both the high chromatic complexity of these materials and the scale with which the samples are studied the proposed process is particularly interesting for materials with complex chromatic characteristics such as highly fractured rocks concrete etc two commercial varieties of highly fractured brecciated dolostones were selected for this study in order to test the designed methodology this new procedure is based on the analysis process of colour images obtained from mesoscopic sample scanning six petrographic parameters and diagrams have been designed in order to quantify the most influential aspects in compressional v p and shear v s ultrasonic wave propagation these petrographic parameters and diagrams are brecciation density brecciation density map clast size distribution fine grained matrix content shape preferred orientation and rose diagrams the results demonstrate that the proposed methodology is suitable for quantifying the petrography of these kinds of materials furthermore the variations measured in v p and v s are fully explained by the values measured for the following parameters brecciation density fine grained matrix content clast size distribution and preferred orientation of clasts

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

salt diapirs in the dead sea basin and their relationship to quaternary extensional tectonics abstract regional extension of a brittle overburden and underlying salt causes differential loading that is thought to initiate the rise of reactive diapirs below and through regions of thin overburden we present a modern example of a large salt diapir in the dead sea pull apart basin the lisan diapir which we believe was formed during the quaternary due to basin transtension and subsidence using newly released seismic data that are correlated to several deep wells we determine the size of the diapir to be 13 10 km its maximum depth 7 2 km and its roof 125 m below the surface from seismic stratigraphy we infer that the diapir started rising during the early to middle pleistocene as this section of the basin underwent rapid subsidence and significant extension of the overburden during the middle to late pleistocene the diapir pierced through the extensionally thinned overburden as indicated by rim synclines which attest to rapid salt withdrawal from the surrounding regions slight positive topography above the diapir and shallow folded horizons indicate that it is still rising intermittently the smaller sedom diapir exposed along the western bounding fault of the basin is presently rising and forms a 200 m high ridge its initiation is explained by localized e w extension due monoclinal draping over the edge of a rapidly subsiding basin during the early to middle pleistocene and its continued rise by lateral squeezing due to continued rotation of the amazyahu diagonal fault

cycles of passive versus active diapirism recorded along an exposed salt wall abstract although it has long been recognised that passive salt diapirism may encompass sub ordinate cycles of active diapirism where sedimentary overburden is periodically shed off the roof of the rising salt there has been very little study of this process around exposed salt halite diapirs however the late miocene pliocene sedom salt wall on the western side of the dead sea basin presents an opportunity for detailed outcrop analysis of diapiric salt and the associated depositional and deformational record of its movement during both passive and active phases of diapirism the sub seismic scale record of diapirism includes sedimentary breccia horizons interpreted to reflect sediments being shed off the crest of the growing salt wall together with exceptional preservation of rotated unconformities and growth faults areas of more pronounced dips directed towards the salt wall are capped by unconformities and interpreted to represent withdrawal basins within the overburden that extend for at least 1500 m from the salt margin elsewhere broad areas of upturn directed away from the salt extend for up to 1250 m and are marked by a sequence of rotated unconformities which are interpreted to bound halokinetic sequences the margins of the salt wall are defined by steep extensional boundary faults that cut upturned strata and have enabled rapid and active uplift of the salt since the holocene the sedom salt wall therefore charts the transition from passive growth marked by withdrawal basins growth faults and unconformities to more active intrusion associated with major boundary faults that enable the rapid uplift of overburden deposited on top of the salt to 100 m above regional elevations in the past 43 ka individual cycles of passive and active diapirism occur over timescales of

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

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

the episodic rise net growing rate and kinematics of radial faults of the salinas de oro diapir using paleoseismological techniques ne spain salt upwelling versus karstic subsidence abstract this paper explores the use of trenching and paleoseismological techniques to determine salt flow rates into a salt diapir for the first time in the literature the salinas de oro diapir located in the northern spanish pyrenees is an oval shaped triassic salt stock that extends vertically for 7 km down to the paleozoic basement salt dissolution subsidence and diapir growth are coeval active processes karstification is responsible for the development of large sinkholes a thick caprock and the monocline folding and ring faulting of the cretaceous and early tertiary limestone rim the evaporite karstic aquifer discharges high concentration water of up to 137 g l of total dissolved solids and a conductivity over 200 ms cm into the salado creek which drains the diapir top the salinity monitoring of this drainage provides a maximum karstic surface lowering rate of around 2 8 mm yr salt upwelling has caused the 150 m uplift of the annular limestone escarpment and the development of 3000 m long radial grabens with up to 90 m of vertical offset that disrupt drainages displace quaternary deposits and overprint concentric faults the 260 cm drag folding of lacustrine facies exposed in a 42 m long and 6 5 m deep trench due to the creep motion of the western radial fault of azanza graben yielded a minimum short term uplift slip rate of 1 75 mm yr for the last 1485 years and provides a minimum salt supply rate of over 5 mm yr considering karstification lowering this value that is several hundred times higher than average evidence the discontinuous growth of salinas de oro diapir

dynamic response of a rocky cliff under the sea wave pulse a study along the adriatic coast of polignano apulia italy the dynamic behavior of a rocky cliff under severe sea waves has been analyzed in the location of polignano facing on the adriatic coast of apulia southern italy in this area the classical and at the same time complex problem of the stability of a cliff in calcareous rocks is burdened by the presence on the top of the cliff of the ancient town to analyze the behavior of the cliff under the impulsive transfer of energy generated by the sea waves two types of measures were carried out on the rocky mass 1 ambient noise and 2 strong motion records the first type of measures which may be executed in a short time with a high spatial density has provided a recognition of the intrinsic and anisotropic dynamic behavior of the coastal cliff the accelerometric records carried out during heavy storms in december 2009 and january 2010 allowed to evaluate the energy transfer from waves to cliff in terms of maximum values and temporal and directional distribution to facilitate a correct interpretation of the measures also a geomechanical characterization of the rocky mass has been carried out through the rock mass rating system bieniawski the geomechanics classification in rock engineering applications proceedings of the 4th isrm cong montreux pp 51 58 1979 bieniawski engineering rock mass classifications wiley new york p 251 1989 and the markland s test a useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected pp 10 1972 the first allowed to classify the rocky masses in terms of quality the second one to individuate the potential failure mechanisms of the cliff

petrographic features influencing basic geotechnical parameters of carbonate soft rocks from apulia southern italy abstract a multidisciplinary petrographic and geotechnical approach aimed at understanding the conditioning by rock fabric on the mechanical properties of carbonate soft rocks is shown in this paper the analysed rocks extensively crop out in the apulia region and can be referred to three geological units pietra leccese late burdigalian early messinian calcarenite di gravina middle pliocene early pleistocene and salentino supersynthem midde late pleistocene 69 specimens of carbonate soft rocks belonging to all these units were selected from different sectors of apulia region and characterized according to petrographic physical and mechanical properties petrographic data allowed us to group all specimens in the following six classes i wackestone ii mud dominated packstone iii packstone iv grainstone v floatstone vi rudstone differently uniaxial compression strength ucs values classify the most part of specimens in very low and low strength revealing a dominant weak resistance and high deformability particular attention has been given to the relationships between petrographic features and physical and mechanical parameters of the apulian soft rocks by means of statistical tests based on the univariate analysis of variance one way anova and on the principal component analysis pca at first statistical analysis revealed that the rock geotechnical values are strictly dependent from the geological units particularly the samples of pietra leccese show significantly higher means of ucs young s modulus et and dry unit weight than samples of the calcarenite di gravina fm conversely samples of this latter unit have significantly higher means of porosity imbibition coefficient and permeability coefficient than those ones of the pietra leccese fm moreover statistical analysis was applied to estimate if geotechnical values differ according to the petrographic classes of the calcarenite di gravina fm and to verify the covariance between the geotechnical parameters of this unit the following results have been remarked i floatstone and rudstone have significantly higher means of ucs and dry unit weight and lower means of porosity than finer grained classes ii mud dominated packstone has significantly lower means of ucs dry unit weight et and permeability coefficient and higher means of porosity and imbibition coefficient than other petrographic classes iii grain dominated matrix free rudstone and grainstone have significantly higher values of permeability coefficient than mud dominated classes iv the occurrence of carbonate lithoclasts and of different dominant couples of sparry cement in pore spaces are two of the most important controlling factors of the rock strength and can also explains much of the intraformational variability observed in geotechnical data total porosity has not a clear correlation with permeability this means that the contribution of isolated pore spaces to the total porosity is relevant in apulian soft rocks as also suggested by the relatively low values of permeability compared to the relatively high percentages of total porosity a multidisciplinary characterization of carbonate soft rocks based on petrographic analysis and geotechnical determination of physical and mechanical properties is here recommended for future studies since this approach can give useful information to understand the peculiar behaviour of carbonate soft rocks and to drive the subsequent geotechnical investigations

the control of mineral constituents and textural characteristics on the petrophysical mechanical pm properties of different rocks of the himalaya abstract petrophysical and mechanical pm properties of a rock are primarily controlled by its mineral constituents and various textural parameters similar rock types in different tectonic setups may be characterized by different mineralogical compositions and textural properties because they might have suffered different deformational processes this paper presents a study on the mineralogical and textural control on various pm properties in quartzites granitoids gneisses metabasics and dolomite collected from different tectonic set ups the inter relationships among mineral constituents various textural parameters unconfined compressive strength ucs schmidt hammer rebound r value seismic wave both p and s waves velocity and their attenuation characteristics were obtained using regression analyses it has been concluded that there exists no relation between ucs and seismic wave velocity in quartzite granitoids and gneisses moderate positive relationship in metabasics and strong negative relationship in dolomite it has further been noted that in quartzite and dolomite monominerelic rocks grain size dominantly control the seismic wave velocity as the relatively coarser grained samples have higher seismic wave velocity whereas ucs is strongly controlled by grain size as well as the quantity and the orientation of the weak minerals like muscovite biotite calcite etc in gneisses and granitic gneisses preferred orientation of minerals especially the mica minerals although in present small quantity is the main factor controlling ucs and seismic velocity both these properties increase with the increase in intensity of preferred alignment of minerals whereas in metabasics it is the presence of amphibole pyroxene minerals feldspar that dominantly controls the seismic wave velocity

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

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

sinkholes collapse structures and large landslides in an active salt dome submerged by a reservoir the unique case of the ambal ridge in the karun river zagros mountains iran abstract ambal ridge covering 4 km2 is a salt pillow of gachsaran formation with significant salt exposures in direct contact with the karun river zagros mountains the highly cavernous salt dome is currently being flooded by the gotvand reservoir second largest in iran geomorphic evidence including the sharp deflection of the karun river and defeated streams indicate that ambal is an active halokinetic structure probably driven by erosional unloading around 30 of the salt dome is affected by large landslides up to ca 50 106 m3 in volume slope oversteepening related to fluvial erosion and halokinetic rise seems to be the main controlling factor a total of 693 sinkholes have been inventoried 170 sinkholes km2 for which a scaling relationship has been produced the depressions occur preferentially along a belt with a high degree of clustering this spatial distribution is controlled by the proximity to the river slope gradient and halite content in the bedrock a large compound depression whose bottom lies below the normal maximum level of the reservoir will likely be flooded by water table rise forming a lake the impoundment of the reservoir has induced peculiar collapse structures 220 280 m across expressed by systems of arcuate fissures and scarps rapid subsurface salt dissolution is expected to generate and reactivate a large number of sinkholes and may reactivate landslides with a significant vertical component due to lack of basal support

rock fabric heterogeneity and its influence on the petrophysical properties of a building limestone lede stone belgium as an example lede stone is an important historical stone in belgium with many ceased and disappeared historical quarries owing to its geological nature this stone exhibits considerable variation in petrophysical properties three macroscopical different facies from the solely remaining quarry area in balegem belgium were profoundly characterized for their pore network properties and petrophysical properties the pore network was exhaustively studied combining water imbibition under vacuum mercury intrusion porosimetry and x ray computed microtomography the three facies not only have a strong difference in total porosity but also differ in terms of pore connectivity and pore size distribution linked to the variability in microfacies this has profound implications on the water transfer properties such as atmospheric water absorption capillary water absorption om nidirectional drying and water vapor resistance the petrophysical behavior is illustrated with a salt ageing test the results can be used for restoration and conservation of lede stone in the built cultural heritage

interpretation of subsurface hydrocarbon shows hydrocarbons occur in the subsurface in four modes 1 continuous phase oil or gas 2 isolated droplets of oil or gas 3 dissolved hydrocarbons and 4 associated with kerogenous rocks all of these modes of occurrence can result in what is described as a subsurface hydrocarbon show each show type has markedly different implications to exploration and must be differentiated as the first step in show interpretation only continuous phase occurrences of oil and gas indicate that a trapped and potentially producible accumulation of hydrocarbons has been discovered free oil or gas recovery from the formation or subsurface hydrocarbon saturations of greater than 55 indicates a continuous phase occurrence continuous phase shows can be interpreted quantitatively the static hydrocarbon column downdip from a continuous phase occurrence can be calculated from one well bore if the subsurface oil or gas saturation capillary properties hydrocarbon water interfacial tension oil density and water density of the reservoir are known producing wells are by definition continuous phase oil or gas and estimates of oil water or gas water contacts from normally available exploration data are practical and reasonably accurate based on a documented field study continuous phase oil or gas can extend either updip or downdip from a commercial reservoir these continuous phase shows can also be interpreted quantitatively to determine how large an oil or gas column is required downdip to explain the show by this method it can be determined whether an exploratory well penetrated the updip waste zone or downdip transition zone of an oil or gas field field studies illustrate that quantitative show interpretation of noncommercial shows can provide reliable estimates of the downdip hydrocarbon column this type of data can be used in a systematic manner to explore for subtle stratigraphic and combination traps

internal deformation and uplift rate of salt walls detected by a displaced dissolution surface dead sea basin abstract despite numerous studies examining salt tectonics relatively little is known regarding the internal movements of salt units that build diapirs such as the mount sedom salt wall in this study we focus on the recent deformation processes of southern mount sedom we choose a fossilized dissolution surface known as the salt mirror of mount sedom as a structural datum in order to understand and resolve the deformation processes during the last 14 ka surveying the salt mirror surface from outcrops and natural dissolution chimney caves sets constraints for the structural map our results indicate that the salt wall rises as a telescopic antenna with the internal salt units sliding across each other along bedding plane slip faults influenced by the subsiding dead sea basin the flow of the rising salt forms an elongated ridge distinctly asymmetric across its short dimension the uplift rate of the southern part of mount sedom throughout the last 14 ka is at least 11 mm yr this result is somewhat higher but in a fair agreement with the results of previous studies that assessed the rates in a variety of methods the telescopic behavior of the salt wall represents a mode of internal deformation that might be applicable to other salt diapirs worldwide

sandstone degradation an experimental study of accelerated weathering the investigated rock material belongs to the group of upper cretaceous quader sandstones which are very important construction stones in poland and germany the mineral composition of the rocks is relatively uniform they are quartzose sandstones the most important feature is their good workability and comparatively high weathering resistance still regardless of the apparent resemblance the observations carried on buildings and monuments show differences in weathering processes the undertaken test was an attempt to verify the proposed before rock classification performed on the basis of parameterization of porosimetric cumulative intrusion volume curves the aim of the experiment was the evaluation of the sandstone petrography including the structure texture and porosity of the rock influence on the weathering process the modelling of accelerated weathering was conducted in chamber for ageing acceleration where some weather circumstances were simulated insolation rain and frost as the result of the weathering experiment it could be stated that the dominant mechanism of the sandstones deterioration was granular disintegration and weight loss as a consequence of sample destruction the most important factor influencing rock deterioration is rock texture especially the character of grain contacts the effective porosity is a requisite of potential for the stone to take in and hold water and hence of resistance to weathering in case of silica cemented sandstones the deciding criterion influencing weathering resistance is pore structure in case of sandstones with clay cement the most important is mineral composition of the rock

susceptibility mapping of instability related to shallow mining cavities in a built up environment anthropogenic activities and urbanization frequently spread over areas underlain by unstable karst ground or man made cavities leading to potential risk situations for buildings infrastructure and population the roof of the cavities may rapidly propagate upwards eventually resulting in progressive ground settlement and or sudden collapse these processes are frequently accelerated or triggered by various human activities e g overloading water recharge water table decline in this paper the susceptibility to instability of artificial cavity networks under an urban area in apulia region southern italy was assessed and evaluated here there is dense network of underground quarries excavated for the extraction of massive calcarenite for building and ornamental stone that are currently affected by severe instability problems identifying the zones of the cavities most prone to instability is of great practical importance susceptibility models have been developed analyzing the statistical relationships between the cavity sections with evidence of instability and a number of predisposing factors mainly related to the 3d geometry of the voids roof thickness and the presence of overloads the models produced by the discriminant analysis and the logistic regression approaches were independently and quantitatively evaluated through the construction of roc curves although the two models are characterized by different input data treatment as the logistic regression allows using continuous and discrete variables or any combination of both types even if they do not have a normal distribution the roc curves highlighted for both methods a satisfactory congruence between the model results and the observed data consequently from the model performance analysis the two models were evaluated comparable in terms of result reliability the methodology should be considered as a general first level analysis for near surface underground cavities aimed at identifying critical cave sectors that can be the focus of more detailed analyses especially those associated with sensitive zone related to the presence of buildings roads and frequent presence of human activity

crustal structure of the dead sea basin from local earthquake tomography summary new findings of the velocity structure of the crust across the dead sea basin are obtained by applying tomography based method to local earthquakes we use p wave traveltime of 614 earthquakes that occurred in the dead sea basin in 1983 2009 at all depths the dead sea basin is characterized by lower velocities relative to both the eastern and western sides of the basin there is significant seismic activity at a depth of about 20 km mainly in the centre and the northern part of the basin at shallow depths 15 km there is more seismic activity on the eastern side of the basin than on the western side and the northern basin is generally more active than the southern basin asymmetry is also observed in the faults that border the dead sea basin the arava fault on the eastern side with nearly vertical dip faulting appears to be a clear boundary at all depths down to about 20 km the depth extension of the jericho fault on the western side of the basin is definitely limited to less than 15 km at greater depths of 20 km or more the western side is only partially bounded by a fault the concentration of earthquakes in the central part of the basin at depths larger than 15 km suggests that the dead sea fault at those depths acts as one single fault that is located in or near the central axis of the basin the existence of a number of clusters of earthquakes that spread from shallow depths of a few kilometres up to a depth of about 22 km points to several defined faults that traverse the dead sea basin one such example is the aftershock sequence of the 2004 earthquake that occurred in the northern dead sea basin seismic activity near mt sodom is relatively low and occurs at shallow depths down to 10 km whereas at larger depths 15 km it ceases this implies that the whole structure is relatively shallow with no wide and deeper extension seismic activity near and within the lisan peninsula extends to somewhat larger depths 15 km and then it ceases the occurrence of earthquakes at large depths suggests that the upper and the lower crust are relatively cool as was also suggested by earlier studies pointing to the fact that the heat flow is significantly below the global average value

fault and salt tectonics in the southern dead sea basin abstract the sedimentary fill of the southern dead sea basin contains large amounts of salt and halokinetic features in this study the relationship between these halokinetic features and major faults was investigated the basis for the interpretation was seismic reflection profiles from the southern dead sea basin the seismic profiles were used to construct a series of two way time structural maps and two way time isochore maps for the various reflectors and sedimentary sequences in the area such maps are published for the first time in the dead sea basin electrical and geophysical logs from wells in the area were used to relate the mapped reflectors and sequences with geological units the seismic profiles give evidence to the largest subsidence that had occurred during the late pliocene and that the amount of subsidence was much larger in the deeper part of the basin than in the median block this difference in subsidence is partly a result of salt withdrawal there are two ways to explain the present day structures of the southern dead sea basin either 1 basement faulting took place before salt deposition or 2 basement faulting took place during or after salt deposition in this research a combination of the two is favored in particular the influence of the movement on the longitudinal fault separating the deeper part of the basin from the median block sedom fault on salt flow is outlined the much larger offset on the sedom fault in the northern part of the area is thought to be the reason for salt piercing only in this part of the area it is also suggested that the sedom fault has experienced strike slip movements and not only vertical movements a ridge the neot hakikar ridge is shown to divide the southern basin into two sub basins the presence of this ridge and the salt tectonics triggered motion on a listric fault amazyahu fault in the early pleistocene the listric curvature of the amazyahu fault induced antithetic faulting recognized in the pleistocene sediments earlier studies have suggested that the depocenter migrated to the north the isochore maps however show that locally the depocenter shifted to the southeast this shift is probably caused by the movement along the amazyahu fault and the withdrawal of salt a much larger amount of salt than previously thought is identified and it is suggested that salt reaches as far south as the iddan fault

an image analysis technique to measure grain size variation in thin sections of soft clastic sediments this paper presents a simple and fast image analysis technique to measure grain size variation in thin sections of soft elastic sediments optical and backscattered electron microscope photographs are digitised from thin sections cut by freeze drying to avoid disturbing the sediments processing of the 256 grey scale images produces binary black and white images where white pixels represent the clay rich sedimentary matrix and black pixels represent elastic grains data measured include grain surface grain perimeter and centre of gravity two indices are defined to quantify grain size d 0 equivalent disk diameter and p phase percentages the technique is applied to silt and clay laminations attributed to the d division of a distal turbidite from lake baikal the data obtained using image analysis are similar to the conventional descriptions of such deposits indices calculated on very small samples e g on a single lamina allow for greater precision in interpretation of sedimentary processes compared to photomicrographs backscattered electron microscope images have better qualities and allow to quantify variations in the grain size along a sediment core the technique produces objective and quantified grain size observations in less time than conventional petrographic methods c 1998 elsevier science b v all rights reserved

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

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

sea level changes since the middle ages along the coast of the adriatic sea the case of st nicholas basilica bari southern italy abstract during the last decade several papers have been published to estimate the relative sea level change from coastal archaeological indicators of the last 3 4 ka bp in many locations of the italian coasts and the mediterranean sea the use of the archaeological information has been poorly focused for the middle ages due to the few available coastal installations for this period thus not allowing precise sea level estimation for the last 1000 years to complement the instrumental data available for the last 100 120 years this study discusses an archaeological marker of the middle ages used to reconstruct the story of the sea level changes in the last 1000 years at the st nicholas basilica built in 1087 ad along the coast of bari apulia southern italy the elevations of the ancient floor levels of the crypt underwent repeated flooding due to a continuous rising of the groundwater table which required restoration and uplifting of pavements between 1087 and 1956 to keep them dry the palaeo sea levels have been obtained by measuring the position of the groundwater table the elevation of which is mainly driven by sea level since the time of the construction of the basilica the elevation of the archaeological markers and the water table were compared against the latest predicted sea level curve for the holocene along the coast of bari as this coastal area is unaffected by significant vertical tectonic motion over the last 125 ky the data detail the timing of the relative sea level rise since the middle ages and can be used to improve the predicted sea level curve for this region for the last 1000 years

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

physical properties and textural parameters of calcarenitic rocks qualitative and quantitative evaluations abstract petrophysical and mechanical properties of sedimentary rocks are influenced by size shape and packing of grains porosity cement and matrix content all controlled strongly by depositional fabric and postdepositional processes this paper presents a study on the textural characteristics of soft and porous calcarenites and the main methods to determine petrophysical data the examined calcarenites sampled from three quarry districts located in apulia southeastern italy are fine grained and coarse grained grainstones a and d and medium grained packstones b belonging to a plio pleistocenic formation calcarenite di gravina outcropping in the whole region the study involved particularly textural analysis on thin sections using optical petrographic microscopy and evaluation of total and effective porosity by means of standard geotechnical laboratory tests mercury intrusion porosimetry and image analysis grain size frequency distribution was also carried out by traditional sieve and sedimentation analysis on disaggregated materials and image analysis computer analysis of digital images was performed on photomicrographs applying the methods of quantitative stereology to pore size and grain size distributions a comparison between results showed that each technique used has its limitations linked to the textural characteristics primarily geometry and topology of the pore network granulometry grain shape and packing of calcarenites

petrography and reservoir physics i objective classification of reservoir porosity porosity observed in thin section can be objectively classified using a combination of digital acquisition procedures and pattern recognition algorithms pore types are derived from the frequency distributions of sizes and shapes of patches of porosity exposed in thin section each pore type is represented by a characteristic distribution of sizes and shapes found in thin section most sandstone reservoirs contain fewer than six pore types much of the intersample variability in reservoir physics is associated with changes in pore type abundance the advantages of this approach to porosity classification are 1 the criteria for classification are objectively defined 2 classification procedure is rapid accurate and precise 3 pore types are understood easily in ter s of conventional genetic classification schemes and 4 pore type data are related strongly to petrophysical properties

the pore system of sedimentary rocks as a key factor in the durability of building materials abstract we studied the pore system of six different types of sedimentary stone two limestones two sandstones one dolostone and one travertine techniques based on the direct observation of the pore system optical and scanning electron microscopes digital image analysis were combined with others used for indirect characterization mercury intrusion porosimetry n 2 adsorption hydric tests and vapour permeability in addition we performed accelerated decay tests to determine the durability of the stones and to check the consistency of the results obtained in the pore system study digital image analysis allowed us to calculate the pore size distribution and the total porosity digital image analysis always gave higher values for total porosity than those determined by porosimetry and hydric tests which only measure open porosity the density values were congruent with the mineralogy of the stones the stone that obtained the best results in the various tests in terms of its petrophysical parameters was dolostone while the worst performance was by one of the two limestones these results were confirmed by the decay tests the combined use of these different techniques gave us an accurate interpretation of the pore systems of the six different stones and also enabled us to correct misleading interpretations caused by the limitations of using one single technique our findings also provide useful information to help prevent the decay of these stones

a visual determination method for uniaxial compressive strength estimation based on croatian carbonate rock materials abstract to identify visually detectable elements that influence carbonate rock strength a detailed inspection of 231 samples mainly from the adriatic carbonate platform in croatia was conducted prior to laboratory testing anova was used to detect statistically significant carbonate rock material parameters that influence ucs lithology fabric defects and porosity lfdp and their optimal classes anova was also used to find a statistically significant model that contains four major effects on the strength of carbonate rock lfdp with three two way interactions lithology fabric fabric defects and defects porosity according to four basic influential parameters the new procedure is coined lfdp determination and is described in detail the presented results indicate that the lfdp determination method is reliable enough for use in engineering geological practice on croatian carbonate rocks but also for use in other regions while the presented method may be applied to other regions worldwide its suitability to local conditions should be tested the lfdp determination method is simple efficient inexpensive and versatile it can be applied to outcrops cuts quarries tunnels borehole cores and similar however it is important to note that this method cannot replace laboratory testing and should be only used to collect preliminary information on carbonate rock material properties and possible ranges in ucs values

unraveling rift margin evolution and escarpment development ages along the dead sea fault using cosmogenic burial ages abstract the dead sea fault dsf is one of the most active plate boundaries in the world understanding the quaternary history and sediments of the dsf requires investigation into the neogene development of this plate boundary dsf lateral motion preceded significant extension and rift morphology by 10 ma sediments of the sedom formation dated here between 5 0 0 5 ma and 6 2 2 1 inf ma yielded extremely low 10be concentrations and 26al is absent these reflect the antiquity of the sediments deposited in the sedom lagoon which evolved in a subdued landscape and was connected to the mediterranean sea the base of the overlying amora formation deposited in the terminal amora lake which developed under increasing relief that promoted escarpment incision was dated at 3 3 0 8 0 9 ma burial ages of fluvial sediments within caves 3 4 0 2 ma and 3 6 0 4 ma represent the timing of initial incision initial dsf topography coincides with the earliest red sea morb s and the east anatolian fault initiation these suggest a change in the relative arabian african plate motion this change introduced the rifting component to the dsf followed by a significant subsidence margin uplift and a reorganization of relief and drainage pattern in the region resulting in the topographic framework observed today

stress evolution and seismic hazard of the dead sea fault system abstract we calculated the stress evolution for the central part of the dead sea fault system 30 5 n 34 5 n from 551 to 2005 through modelling the static stress changes due to 14 historical earthquakes with m s 6 0 superimposed by tectonic loading from relative plate motion from the results of our numerical models we identified two segments with high positive changes in coulomb failure stress cfs exceeding 4 mpa a 90 km long segment of the jordan fault south of the sea of galilee and a 30 km long segment east of the dead sea these segments could result in m s 7 4 and m s 6 8 earthquakes respectively in contrast to similar stress evolution models of other continental transform faults our results support only partly the hypothesis that coseismically induced static stress changes control the spatial succession of earthquakes we calculated on each rupture plane the mean of cfs and the maximum cfs due to the stress changes of all preceding earthquakes the results of the calculated mean cfs values reveal that only 6 out of 13 earthquakes could have been triggered the subsequent earthquake from the analysis of the maximum cfs values we find that 8 out of 13 earthquakes could have triggered the subsequent earthquake since our model results are sensitive to location and magnitude of historical earthquakes and the tectonic loading rates of the fault segments we emphasize the need for further paleoseismological studies and current slip rate estimation from continuously observing gps arrays and geological investigations taking into account that six large cities beirut damascus haifa tel aviv amman and jerusalem are in close proximity with distances between 30 and 150 km to the jordan segment the seismic risk is probably higher than accounted before