the present day stress field of australia abstract the unusual present day crustal stress pattern of the australian continent has been the subject of scientific debate for over 25 years the orientation of maximum horizontal present day stress s hmax in continental australia is unlike all other major tectonic plates in that the stress pattern shows regional variability and it is not oriented sub parallel to the direction of absolute plate motion previous studies on the stress pattern of australia revealed that the complex stress pattern of the continent is controlled at a first order by the superposition of plate tectonic forces exerted at the plate boundaries however prior analysis of the contemporary australian crustal stress pattern have been unable to model or explain the stress pattern observed in most of eastern australia and has not extensively addressed the numerous smaller scale variations in stress orientation the recent development of unconventional reservoirs in australia has resulted in a greatly increased amount of new data for stress analysis in previously unstudied or poorly constrained areas in eastern australia in addition stress analysis in conventional hydrocarbon mineral and geothermal exploration in all other parts of the continent provides the opportunity to review and update the australian stress map asm this study presents the new release of the asm with a total of 2150 stress data records in australia increased from 594 data records in 2003 the 2016 asm contains 1359 data records determined from the interpretation of drilling related stress indicators 650 from earthquake focal mechanism solutions 139 from shallow engineering measurements and two from geological indicators the results reveal four distinct regional trends for the s hmax orientation in australia including a nne ssw s hmax trend in northern and northwestern australia which rotates to a prevailing e w orientation in most western and south australia the orientation of s hmax in eastern australia is primarily ene wsw and swings to nw se in southeastern australia a comparison between the new asm database and neotectonic features further confirms the role of contemporary stress in recent deformation of the australian crust the 2016 asm reveals significant discrepancies between newly observed s hmax orientations and predictions by published geomechanical numerical models for the australian continent forces generated at the boundary of indo australian plate remain the major control on the regional crustal stress pattern in continental australia however the increased data density particularly in eastern australia reveals numerous local perturbations of the stress field that were not previously clearly captured hence the key findings of the new release are that local intra plate stress sources are more significant than previously recognized particularly in eastern australian basins and cause substantial local scale rotations of the present day crustal stress pattern that have not been factored into existing australian stress models

stress magnitude and orientation in the potiguar basin brazil implications on faulting style and reactivation 1 we analyzed borehole breakout data and drilling induced tensile fractures derived from resistivity image logs run at 10 oil wells to derive the orientation of the maximum horizontal stress shmax from the potiguar basin in the continental margin of brazil stress magnitudes are derived from density logs for the vertical stress mini frac tests for the minimum horizontal stress shmin and rock strength laboratory analysis to estimate the shmax magnitudes we compared these results with the stress regime and shmax orientation derived from nine earthquake series located in the crystalline basement where seismicity is concentrated and previous breakout data from the basin in the basin the shmax gradient is 20 0 mpa km and the shmax shmin ratio is 1 154 indicating a normal tectonic stress regime from 0 5 to 2 0 km whereas the shmax gradient of 24 5 mpa km and shmax shmin ratio of 1 396 indicate a transition from a normal to strike slip stress regime at 2 5 to 4 0 km the deeper stress regime in the basin is similar to that in the basement at 1 12 km depth this transition of the tectonic stress regime is consistent with an incipient tectonic inversion in the basin we note that the shmax orientation rotates from nw se in the western part of the potiguar basin to e w in its central and eastern parts roughly following the shoreline geometry indicating that local features such as flexural stresses influence the local scale 100 km stress pattern we also conclude that the basement is critically stressed but not the basin

coalbed methane completions a world view abstract cbm wells are cheap because they are usually shallow deeper wells tend to have lower coal permeability and productivity low permeability is the weak point achilles heel for cbm ventures and success will entail finding regions of enhanced permeability utilizing horizontal wells with the option of fracturing these wells and possibly in creating permeability by new paradigm methods such as shear stimulation and branch fracturing this paper discusses the role of permeability in choosing cbm completions as well as examples of those completions from around the world the guidelines offered are new and practical including perm bands and a decision tree and should benefit any cbm completion strategy

present day stress field rotations associated with evaporites in the offshore nile delta evaporitic horizons are routinely interpreted to act as mechanical detachment sequences and thus signifi cantly infl uence the structural evolution of sedimentary basins and fold thrust belts however over 30 years of global in situ stress analysis have provided only poor evidence to support this widespread assumption this study examines present day stress orientations inferred from borehole breakout and drilling induced fractures in 44 boreholes in the offshore nile delta a total of 446 breakouts and 19 drilling induced fractures from 37 wells reveal sharply contrasting present day maximum horizontal stress shmax orientations in sequences above and below the extensive messinian evaporites of the eastern nile delta a typical deltaic margin parallel shmax e w in the central and ese wnw in the eastern nile delta is observed in parts of the nile delta that are below or do not contain evaporites however a scattered but largely margin normal nne ssw shmax is observed in sequences underlain by evaporites the 90 variation in present day shmax orientation above and below the messinian salts provides the fi rst convincing in situ evidence that evaporite sequences can act as major mechanical detachment horizons in addition the margin normal shmax orientation is subperpendicular to the strike of nearby active extensional faults indicating the existence of non andersonian faulting in the suprasalt region furthermore the evidence that the messinian evaporites act as an effective mechanical detachment suggests that suprasalt faulting in the eastern nile delta is not the result of basement related deformation and thus raises doubts about the often postulated extension of the suez fault zone into the eastern mediterranean

global crustal stress pattern based on the world stress map database release 2008 the world stress map wsm project is a global compilation of information on the contemporary crustal stress field from a wide range of stress indicators the wsm database release 2008 contains 21 750 stress data records that are quality ranked using an updated and refined quality ranking scheme almost 17 000 of these data records have a c quality and are considered to record the orientation of maximum horizontal compressional stress sh to within 25 as this is almost a triplication of data records compared with the first wsm database release in 1992 we reinvestigate the spatial wave length of the stress patterns with a statistical analysis on a global 0 5 grid the resulting smoothed global stress map displays both the mean sh orientation that follows from the maximum smoothing radius for which the standard deviation is b25 and a countour map that displays the wave length of the stress pattern this smoothed global map confirms that long wave length stress patterns n2000 km exist for example in north america and ne asia these have been used in earlier analyses to conclude that the global stress pattern is primarily controlled by plate boundary forces that are transmitted into the intraplate region however our analysis reveals that rather short wave length of the stress pattern b200 km are quite frequent too particularly in western europe alaska and the aleutians the southern rocky mountains basin and range province scandinavia caucasus most of the himalayas and indonesia this implies that local stress sources such as density contrasts and active fault systems in some areas have high impact in comparison to plate boundary forces and control the regional stress pattern

long term behaviour of australian stable continental region scr faults abstract australia boasts arguably the richest late neogene to quaternary faulting record in stable continental region scr crust anywhere in the world variation in fault scarp length vertical displacement proximity to other faults and relationship to topography permits division of the continent according to fault character six onshore neotectonic domains are recognised with an additional offshore domain proposed by analogy with the eastern united states each domain relates to a distinct underlying crustal type and architecture broadly considered to represent cratonic non cratonic and extended environments in general greater topographic expression associated with faults occurring in extended crust relative to non extended crust suggests a higher rate of seismic activity in the former setting consistent with observations worldwide using the same reasoning non cratonic crust might be expected to have a higher rate of seismic activity than cratonic crust this distinction together with the variation in fault character between domains should be recognised in attempts to identify analogous systems worldwide a common characteristic of morphogenic earthquake occurrence in australia appears to be temporal clustering periods of earthquake activity comprising a finite number of large events are separated by much longer periods of seismic quiescence at the scale of a single fault and of proximal faults in several instances there is evidence for deformation at scales of several hundred kilometres switching on and off over the last several million years what is not clear from the limited palaeoseismological data available is whether successive active periods are comparable in terms of slip number of events magnitude of events etc regardless this apparent bimodal recurrence behaviour poses challenges for probabilistic seismic hazard assessment psha these rely on the simplifying assumption that large earthquake recurrence for long return periods is not random i e poissonian presently our ability to incorporate such time dependent models is limited by available data

smoothing and extrapolation of crustal stress orientation measurements the theory and mechanics of a statistical smoothing algorithm for estimating stress fields based on observed data are described incorporated into the algorithm are tunable parameters which allow the user to adjust the smoothness and fidelity of the fitted stress field in addition the user has the option of using robustness weights or to weight the predicted stress field by assigning quality ranks to each data point fitted stress fields can be displayed as either a gridded map axes of maximum or minimum horizontal stress are shown as short bars located at each point in an evenly spaced grid or as a stress trajectory map examples of predicted stress fields for southern california and western canada based on borehole elongation data are displayed as stress trajectory maps a predicted paleostress field for the spanish peaks intrusion complex in colorado based on vertical dike orientations is displayed as a gridded map the smoothing algorithm is not limited to the analysis of stress orientation data any data consisting of a set of undirected lines measured at discrete locations are appropriate for input possible candidates include strain data mineral or intersection lineations and lineaments

crustal stress determination from boreholes and rock cores fundamental principles abstract obtaining quantitative information on the state of stress in the crust can only be accomplished by accessing the zone of interest by drilling the borehole cavity however disrupts the virgin stress state by concentrating stresses in predictable patterns with a number of consequences at sufficiently low stress magnitudes the concentrated stresses amplify the elastic anisotropy azimuthally around the borehole because the elastic properties of most rocks depend nonlinearly on stress at higher levels the stresses damage then fracture the rock near the wellbore wall or within a growing core stub indeed almost all of the borehole techniques indirectly measure stress through these manifestations of the concentrated stresses this contribution reviews at a fundamental level the concentration of stresses by the borehole the effects on the materials in the borehole s vicinity and how these are used to infer stress states stress concentrations applied to rocks which are generally nonlinear elastic materials induce both radial and azimuthal variations in elastic wave speeds near the borehole that can be used to infer stress directions from advanced acoustic logging methods hydraulic fractures initiate propagate and remain propped open by measured pressures that can be interpreted with knowledge of the stress concentrations to obtain quantitative stress magnitudes at higher stress levels the rock fails producing borehole breakouts or drilling induced tensile fractures both of which are indicative of stress directions and can be used to constrain stress magnitudes similarly the various styles of drilling induced core fractures indicate both stress directions and the faulting environment encountered unfortunately no method currently allows for complete determination of the stress tensor using a number of different but complementary techniques is necessary to best constrain in situ stress states

columbite group minerals and mica of peraluminous granite record the magmatic hydrothermal processes that formed the zhaojinggou tanb deposit in the north china craton abstract the newly discovered zhaojinggou ta nb deposit in the northern margin of the north china craton contains ore reserves of more than 38 mt at an average grade of 0 013 wt ta2o5 and 0 012 wt nb2o5 the ta nb mineralization is mainly hosted in a peraluminous albite granite body which is about 400 m long and 20 to 100 m wide with a surface exposure of 0 05 km2 granitic pegmatites and greisen veins that range from several centimeters to meters in width occur in the margin of the granite body and wolframite quartz veins intrude the wall rocks up to tens of meters away from the granite contact la icp ms u pb dating for columbite of the granite yields the lower intercept ages between 131 8 1 0 ma and 134 6 2 1 ma on the tera wasserburg concordia diagram indicating that the mineralization occurred in the early cretaceous coeval with the peak stage of lithospheric thinning and destruction of the north china craton the columbite grains in the granite are commonly euhedral and are surrounded or penetrated by irregular tantalite patches rims containing ta2o5 as high as 59 5 wt the ta concentrations within single columbite crystals commonly increase slightly from the center outwards consistent with a systematic decrease of nb ta caused by crystallization of columbite from the silicic magma mica in the granite shows disordered bright and dark domains in their bse images bright domains are f rich zinnwaldite crystallized from highly evolved melts that were relatively enriched in fe li rb nb and ta whereas the dark domains are f poor muscovite crystallized from later hydrothermal fluids that were relatively enriched in al mn ba sn and w it is thus likely that the tantalite patches rims around the columbite grains crystallized from a ta and f rich hydrosilicate melt in a magmatic hydrothermal transitional stage the wolframite quartz veins adjacent to the granite body likely formed from a w rich hydrothermal fluid

tracking textural mineralogical and geochemical signatures in soils developed from basalt derived materials covered with loess sediments sw poland abstract this study investigates the scale of inheritance of signatures typical of loess and basalt derived substrates in soils having both components present as parent material due to past periglacial processes based on field description particle size distribution mineralogy heavy minerals and clay minerals as well as geochemistry we track the signal of both materials local basalt derived and loess derived estimate the maximum thickness of loess mantles and mixed zones having both loess and basaltic components and note the presence or absence of basal layers without allochtonous additions the results show that geochemistry and heavy minerals are the most reliable proxies for a verification of aeolian silt contributions and to define individual layers in complex soil parent materials soil formation in the studied landscape depends on the type of slope sediments typical fine grained weathering of basalt without input from aeolian silt would promote rather vertic development however in thick loess deposits as well as in thin silt textured materials superimposed on clay loam beds clay illuviation dominates development of argic horizons however results in decreasing permeability promoting water stagnation and enhanced degradation processes in clay rich subsoil instead of luvisols stagnosols and retisols developed in the study regions basaltic block covers mixed with loess host cambic horizons based on our findings it seems that at the edge of thin loess deposits no soils exist that developed exclusively from basaltic parent materials

rotation of horizontal stresses in the australian north west continental shelf due to the collision of the indo australian and eurasian plates there is a 40 rotation of regional maximum horizontal stress hmax orientation between the western end of the australian north west continental shelf carnarvon basin and its eastern end bonaparte basin a total of 625 borehole breakouts covering a cumulative length of 7 7 km in 42 wells in the carnarvon basin indicates a hmax orientation of 090 100 n a total of 616 borehole breakouts over 6 8 km in 46 wells in the bonaparte basin indicates a hmax orientation of 055 n 060 n together with extant data from the world stress map these results indicate that regional hmax orientation is 050 060 n from new guinea westward through the bonaparte basin to the canning basin central north west shelf between the canning basin and the carnarvon basin hmax rotates to 090 100 n the parallelism of hmax orientation in the bonaparte basin to the australia banda arc collisional zone indicates that this collision is not generating significant net push rather the 050 060 n hmax orientation of much of the northern australian margin is probably controlled by the more mature new guinea orogen to which it is approximately orthogonal the observed rotation of hmax can be explained solely by the focusing of the forces balancing ridge push along collisional segments of the northeastern boundary of the indo australian plate such as the new guinea orogen although not required to account for the observed stress rotation a slab pull force from oceanic indo australian plate being subducted beneath the sunda arc cannot be dismissed

understanding tectonic stress in the oil patch the world stress map project knowledge of the present day tectonic stress is essential for numerous applications in petroleum exploration and production and in civil and mining engineering such as improving the stability of boreholes and tunnels and enhancing petroleum production through natural or induced fractures the world stress map wsm project is a collaborative project between academia industry and government that is building a comprehensive global database of present day stress information to better understand the state and sources of contemporary tectonic stress in the lithosphere figure 1

present day stress field of southeast asia article i nfo it is now well established that ridge push forces provide a major control on the plate scale stress field in most of the earth s tectonic plates however the sunda plate that comprises much of southeast asia is one of only two plates not bounded by a major spreading centre and thus provides an opportunity to evaluate other forces that control the intraplate stress field the cenozoic tectonic evolution of the sunda plate is usually considered to be controlled by escape tectonics associated with india eurasia collision however the sunda plate is bounded by a poorly understood and complex range of convergent and strike slip zones and little is known about the effect of these other plate boundaries on the intraplate stress field in the region we compile the first extensive stress dataset for southeast asia containing 275 a d quality 177 a c horizontal stress orientations consisting of 72 stress indicators from earthquakes located mostly on the periphery of the plate 202 stress indicators from breakouts and drilling induced fractures and one hydraulic fracture test within 14 provinces in the plate interior this data reveals that a variable stress pattern exists throughout southeast asia that is largely inconsistent with the sunda plate s approximately ese absolute motion direction the present day maximum horizontal stress in thailand vietnam and the malay basin is predominately north south consistent with the radiating stress patterns arising from the eastern himalayan syntaxis however the present day maximum horizontal stress is primarily oriented nw se in borneo a direction that may reflect plate boundary forces or topographic stresses exerted by the central borneo highlands furthermore the south and central sumatra basins exhibit a ne sw maximum horizontal stress direction that is perpendicular to the indo australian subduction front hence the plate scale stress field in southeast asia appears to be controlled by a combination of himalayan orogeny related deformation forces related to subduction primarily trench suction and collision and intraplate sources of stress such as topography and basin geometry

reconstruction of late pleistocene paleoenvironments in southern germany using two high resolution loess paleosol records abstract two loess paleosol sequences from the heilbronn basin in southwestern germany frankenbach and talheim have been investigated to gain information about environmental conditions during the last interglacial glacial cycle since paleoenvironmental research on terrestrial archives is crucial for a better understanding of past climatic and environmental conditions the profiles were studied using a multi proxy approach applied methods include the analyses of grain size distribution element contents sediment color rock magnetism micromorphology and black carbon bc via benzene polycarboxylic acids bpca the data reveal that the two profiles show large variations in conservation due to their different geomorphologic positions moreover the results imply a subarctic climate with stable conditions during the middle pleniglacial mis 3 in situ soil formation phase while the lower pleniglacial mis 4 was characterized by erosion and reworking of eemian and early glacial mis 5 material but also by accumulation of aeolian material during the late lower pleniglacial mis 4 in frankenbach the results further suggest that the rhine river floodplain has been a major source for the accumulated material in the two profiles which indicates westerly wind directions during the time of accumulation the low gsi and u ratio of upper pleniglacial mis 2 sediments supported by the overall high content of fine material imply a larger distance to the source area we give an overview of loess in the heilbronn basin and place it in a wider context of loess in western europe

stress field of italy mean stress orientation at different depths and wave length of the stress pattern we have studied the stress pattern of italy using a dataset with 590 data records from the world stress map database release 2008 and 106 new data records to test the hypothesis the mean orientation of maximum horizontal stress sh is different at different depth sections for this we split the dataset into a shallow 0 6 km and a deep 6 40 km depth section for the data analysis we used a new statistical tool that calculates the mean sh orientation on a 0 2 grid the tool takes into account the distance to each grid point number and quality of the data records within the search radius and the radial distribution the result is a smoothed italian stress map that displays both the mean sh orientation and the wave length of the stress pattern the stress pattern does not vary in depth except for two areas sardinia and southern apulia therefore stress data from different depths can be used to estimate the mean sh orientation and the wave length of the stress pattern in italy furthermore the smoothed italian stress map reveals that most of italy has short wave length stress patterns 150 km this indicates that the stress field is not controlled by first order stress sources of plate tectonics i e the convergence of africa with respect to eurasia but that second order stress sources such as topography density strength contrasts and major faults systems are of great importance in four regions western part of the alps northern tuscany northern adriatic sea calabria and eastern part of sicily the wave length is 100 km high values of the circular variance of the mean sh orientation observed here are driven by third order local stress sources such as basins or local neotectonic structures

earthquakes as beacons of stress change aftershocks occurring on faults in the far field of a large earthquake rupture can generally be accounted for by changes in static stress on these faults caused by the rupture1 2 this implies that faults interact and that the timing of an earthquake can be affected by previous nearby ruptures3 4 5 6 here we explore the potential of small earthquakes to act as beacons for the mechanical state of the crust we investigate the static stress changes resulting from the 1992 landers earthquake in southern california which occurred in an area of high seismic activity stemming from many faults we first gauge the response of the regional seismicity to the landers event with a new technique and then apply the same method to the inverse problem of determining the slip distribution on the main rupture from the seismicity assuming justifiable parameters we derive credible matches to slip profiles obtained directly from the landers mainshock7 8 our results provide a way to monitor mechanical conditions in the upper crust and to investigate processes leading to fault failure

isrm suggested methods for rock stress estimation part 3 hydraulic fracturing hf and or hydraulic testing of pre existing fractures htpf contents1 introduction 10112 summaryoftestmethods 10123 assumptionsandlimitations 10123 1 hydraulicfracturing hf 10123 2 hydraulictestsonpre existingfractures htpf 10124 apparatus 10134 1 fractureorientationdetectiondevices 10145 personnelquali cation 10146 equipmentperformance 10147 hydraulicfracturingtestprocedure 10148 hydraulic fracturedelineation 10168 1 impressionpackertechnique 10168 2 geophysicalimagingtechnique 10179 obtainingcriticalpressureparametersfromthepressure timerecords 101710 stresscalculations 101810 1 hydraulicfracturing hf 101810 2 hydraulictestsonpre existingfractures 101911 reportingofresults 1019references 1020

nw australian intraplate seismicity and stress regime 1 the interrelations between stress orientation regional deformation and seismic activity in the context of intraplate seismicity continue to pose difficult questions stress models of the australian continent are largely based on nonseismic information our study of 26 microearthquakes in nw australia shows that they are good indicators of the seismogenic stress field by inverting focal mechanisms calculated from the events we obtained deviatoric stress tensors in full agreement with the known in situ stress field the stress tensors corroborate the elastic modeling of the continent the methods used here have widespread applicability in determining crustal stress field parameters in regions where in situ stress data are sparse or absent

paleostress field evolution of the australian continent since the eocene 1 although the low order present stress field of most continents is fairly well established information on paleostress fields is generally sparse knowledge of paleostresses is crucial for understanding brittle tectonic reactivation through time the indian australian plate lends itself well to a reconstruction of paleostresses as it has undergone enormous changes in plate driving forces through the tertiary and there is a rich record of fault reactivation from sedimentary basins we reconstruct the plate boundary configuration and age area distribution of ocean crust around australia through time to obtain estimates for ridge push slab pull and collisional forces acting on the indian australian plate since the eocene other model parameters we explore are the effects of the australian antarctic discordance and the mechanical strength of the australian continental margin we apply these constraints to model the orientation of the maximum horizontal compressive stress shmax regime for the present early miocene and early eocene using the commercial software abaqus along with the optimization software nimrod o we use an elastic two dimensional plane stress finite element model with a resolution of 0 2 in both longitude and latitude realistic elastic parameters representing different rock types and geologic provinces for the australian continent have been included to model the stress field of a heterogeneous plate we show that spatially significant rotations of shmax directions can be modeled as a consequence of perturbations of shmax in areas of juxtaposed rigid and compliant rheologies the absence of the collisional papua new guinea boundary in the miocene and reduced ridge push force from the south result in stress directions considerably different from the present stress directions over the northern australian continent in the early miocene in particular show large disparity with present stress directions stress orientations for the australian plate during the early eocene are controlled predominantly by ridge push forces arising from spreading in the wharton basin in the indian ocean and vary substantially with stress directions in the early miocene and the present because of the drastically different plate geometry and boundary configurations fault reactivation histories observed on the northwest shelf of australia and in the bass strait region are consistent with modeled changes in stress directions through time

undrained poroelastic response of sandstones to deviatoric stress change deformation of porous crustal rock through diagenesis tectonic loading or other processes can change pore volume and affect fluid pressure the largest stress induced pore pressure changes occur when fluid is trapped in pores in an undrained condition we have measured the undrained poroelastic response of two sandstones to changes in mean and deviatoric stress pore pressure was found to respond to mean stress m in the usual manner p b m b ranging from 0 4 to 0 7 nearly independent of the ambient deviatoric stress state however variations in deviatoric stress d 1 3 2 at constant mean stress were also found to induce a reversible elastic pore pressure response to stress levels up to and exceeding 80 percent failure stress i e p d m const the coefficient became more negative with increasing deviatoric stress level in sandstone and ottawa sand samples that is represents a dilatant response where increased deviatoric stress causes a decrease in pore pressure the poroelastic response to deviatoric stress is explained in terms of anisotropic matrix stiffening due to closure of crack like pore space or flattening of grain contacts at high ambient stress levels and can be important in calculations of earthquake stress transfer

flash vaporization during earthquakes evidenced by gold deposits fluids flowing through cavities in earth s crust can deposit gold thermo mechanical modelling of a fluid filled cavity that expands suddenly during an earthquake shows that the drop in pressure would cause the fluid to vaporize and deposit the gold almost instantaneously

plate boundary forces are not enough second and third order stress patterns highlighted in the world stress map database 1 the world stress map project compiles a global database of contemporary tectonic stress information of the earth s crust early releases of the world stress map project demonstrated the existence of first order plate scale stress fields controlled by plate boundary forces and second order regional stress fields controlled by major intraplate stress sources such as mountain belts and zones of widespread glacial rebound the 2005 release of the world stress map project database provides for some areas high data density that enables us to investigate third order local stress field variations and the forces controlling them such as active faults local inclusions detachment horizons and density contrasts these forces act as major controls on the stress field orientations when the magnitudes of the horizontal stresses are close to isotropic we present and discuss examples for venezuela australia romania brunei western europe and southern italy where a substantial increase of data records demonstrates some of the additional factors controlling regional and local stress patterns

stress induced borehole elongation a comparison between the four arm dipmeter and the borehole televiewer in the auburn geothermal well the nature and origin of borehole elongation recorded by the four arm dipmeter calipers is studied utilizing information obtained from hydraulic fracturing stress measurements and borehole televiewer data taken in a well located in auburn new york a preferred orientation n10 w s10 e 10 and a less prominant e w orientation of borehole elongation was observed on two runs of the dipmeter comparisons of borehole geometry determined using the televiewer and the dipmeter show that both tools give the same orientation of borehole elongtion provided that the zone of elongation is longer than 30 cm comparisons of dipmeter caliper data with orientation of in situ stress and natural fractures obtained from hydrofracturing tests and televiewer data show that the n10 w s10 e borehole elongations 1 are axisymmetric 2 are aligned with the minimum horizontal stress sh and 3 are not associated with natural fractures intersecting the well these elongations are interpreted as stress induced well bore breakouts the e w elongation direction is characterized by an asymmetric borehole cross section in thinly bedded rocks and is not caused by breakouts this asymmetric geometry can be discriminated from breakouts using the oriented electric measurements provided by the dipmeter this study demonstrates that the dipmeter can be used to determine the orientation of sh by mapping breakouts confirming the results of earlier less detailed studies and provides a firm basis for mapping regional stress patterns using existing dipmeter data

attached or not attached evidence from crustal stress observations for a weak coupling of the vrancea slab in romania abstract the crustal stress pattern of romania provides key insights into whether the vrancea slab with its seismogenic volume between 70 and 175 km depth is still coupled to the crust and thus acts as a stress guide or whether it is already in a state of detachment from the crust knowledge of the state of the slab under vrancea is particularly critical because the slab attached to the crust can result in future strong earthquake occurrence in the crust and even in the currently aseismic zone between 40 km and 70 km depth potentially causing severe damage our analysis of the contemporary tectonic stress observations in the context of potential stress sources and the comparison with numerical modelling shows that the crustal stress pattern in romania is heterogeneous and does not contain a long wave length stress pattern that would be expected if there is a strong present day coupling between the subducted slab and the upper plate or if lateral plate boundary forces would control the regional stress pattern therefore we conclude that the crustal stress pattern of romania is characterised by small differential horizontal stresses where local stress sources third order effects are responsible for the observed heterogeneity of stress orientations and that the subducted slab under vrancea is only weakly coupled to the crust

in situ stress from breakouts in the danish sector of the north sea abstract borehole breakouts from 26 wells situated in the danish central graben and one well situated in the northwestern section of the ringkobing fyn high have been studied the data provide information on the orientation of the contemporary principal horizontal stresses down to depths of 4 7 km statistics were used to obtain a mean azimuth of breakouts for each well and each individual breakout was weighted by its length data quality of breakouts is assigned according to the world stress map quality ranking scheme the breakout data reveal that s h orientations in the danish central graben are extremely scattered no regional trend in mean s h orientation can be identified as a result of the large standard deviation 77 similar scatterings of s h orientations have been reported from adjacent regions of the north sea the results indicate that the state of stress in the sedimentary cover of the danish central graben is influenced by a local stress generating mechanism rather than platewide stress transmissions mechanisms three units with different states of stress have been identified and found to correspond somewhat with the lithostratigraphic divisions of the post chalk group chalk group and pre chalk group

on the modified mercalli intensities and magnitudes of the 1811 1812 new madrid earthquakes we reexamine original felt reports from the 1811 1812 new madrid earthquakes and determine revised isoseismal maps for the three principal mainshocks in many cases we interpret lower values than those assigned by earlier studies in some cases the revisions result from an interpretation of original felt reports with an appreciation for site response issues additionally earlier studies had assigned modified mercalli intensity mmi values of v vii to a substantial number of reports that we conclude do not describe damage commensurate with intensities this high we investigate several approaches to contouring the mmi values using both analytical and subjective methods for the first mainshock on 02 15 lt december 16 1811 our preferred contouring yields m 7 2 7 3 using the area moment regressions of johnston 1996 for the 08 00 lt on january 23 1812 and 03 45 lt on february 7 1812 mainshocks we obtain m 7 0 and m 7 4 7 5 respectively our magnitude for the february mainshock is consistent with the established geometry of the reelfoot fault which all evidence suggests to have been the causative structure for this event we note that the inference of lower magnitudes for the new madrid events implies that site response plays a significant role in controlling seismic hazard at alluvial sites in the central and eastern united states we also note that our results suggest that thrusting may have been the dominant mechanism of faulting associated with the 1811 1812 sequence

triggering of the lusi mud eruption earthquake versus drilling initiation abstractthe lusi mud volcano in east java has erupted unabated for almost 2 yr ooding an area of 7 km 2 and displacing more than 25 000 people despite its disastrous impact the mechanism for triggering the lusi eruption remains highly controversial two distinct mechanisms have been proposed one hypothesis suggests that the eruption was triggered by the m w 6 3 earth quake that struck yogyakarta 250 km from lusi two days before the eruption however an examination of static and dynamic stress changes and stress transfer mechanisms indicates that the yogyakarta earthquake was at least an order of magnitude too small to reactivate faults and open uid ow pathways under lusi an alternate theory suggests that lusi was triggered by a blowout following drilling problems in the nearby banjar panji 1 well blowouts result from an inability to control pore uid intakes into the borehole and typically occur when the drilling win dow fracture pressure minus pore pressure is approximately zero and when there is insuf cient protective casing of the well bore pore and fracture pressure data from banjar panji 1 indicate that the well had a narrow drilling window of only 0 2 3 mpa furthermore two planned casing points were skipped during drilling resulting in 1742 m of unprotected borehole the combina tion of hazardously narrow drilling window and long uncased borehole would have made drill ing problems in banjar panji 1 dif cult to control placing the well at high risk of blowing out furthermore well bore pressures following drilling problems in banjar panji 1 reached magni tudes in excess of the fracture pressure and thus were suf cient to create uid ow pathways in the subsurface therefore we suggest that no viable method is known by which the yogyakarta earthquake could have triggered the mud ow and that a blowout in the banjar panji 1 well was the most likely mechanism for triggering the lusi eruption keywords

present day stress and neotectonic provinces of the baram delta and deep water fold thrust belt abstract we present the first present day stress orientation measurements across a delta and deep water delta toe fold thrust belt stress and neotectonic data for nw borneo reveal three discrete neotectonic provinces an inverted inner shelf province where present day maximum horizontal stress h is oriented margin normal an extensional delta top province h is margin parallel and a compressional delta toe province h is margin normal we interpret the delta top and delta toe data to reflect that compression in the fold thrust belt is coupled to delta top extension and that the inverted inner shelf province reflects the location of this system on an active margin

in situ stresses in the southern bonaparte basin australia implications for first and second order controls on stress orientation four arm dipmeter logs from six wells and a formation microscanner fms image log from one well in the southern bonaparte basin were interpreted for in situ stress indicators results of the analysis reveal a consistent ne sw in situ maximum horizontal stress hmax orientation 055 n this orientation is parallel to the average hmax determined in the northern bonaparte basin the onshore canning basin and in new guinea the data support the interpretation that the ne sw hmax orientation in the area reflects a first order stress pattern controlled by plate boundary forces along the northeastern margin of the indo australian plate iap and contradict the suggestion that ne sw hmax in the northern bonaparte basin is a second order effect associated with boundary induced flexural stresses numerical modeling suggests that the divergence of hmax from an orientation parallel to plate motion can be explained by the heterogeneous nature of the northeastern boundary of the iap

the influence of pleistocene landforms on soil forming processes and soil distribution in a loess landscape of baden wurttemberg south west germany abstract geomorphodynamic and pedogenetic processes were studied in a dry valley the borten valley within a typical loess region near heilbronn land use in this area is very intensive and causes serious soil erosion problems soil mapping showed the degree of erosion of luvisols and the resulting mosaic of different erosion and accumulation patterns soil profiles on slopes have been eroded and soils with relict properties in valley bottoms and on lower slope positions gleyic chernozems and intergrades to luvisols have been covered by colluvial sediments these paleosols provide evidence for holocene soil evolution the transformation of gleyic chernozems to luvisols depended mainly on geomorphology and hydrological conditions the preservation of paleosols also allows the landscape before anthropogenic deforestation to be reconstructed

stress in the indo australian plate cloetingh s and wortel r 1986 stress in the ind austr ian plate in b johnson and a w bally editors intraplate deformation characteristics processes and causes tectonophysics 132 49 67 we modelled the state of stress in the indo australian plate in order to investigate quantitatively variations observed in tectonic style the numerical procedure incorporates the dependence of slab pull and ridge push on the age of the oceanic lithosphere estimates are presented for the average net resistive forces at the himalayan collision zone the suction force acting on the overriding indo australian plate segment at the tonga kermadec trench and the drag at the base of the lithosphere our modelhng shows a concen ation of compressive stresses of the order of 3 5 lcbar in the ninetyeast ridge area the effects of the compressive resistance associated with himalayan collision and subduction of young lithosphere off the northern part of the sunda arc are focused in this region the stress field as calculated gives a consistent explanation for the observed concentration of seismic activity stein and okal 1978 and significant deformation in the oceanic crust weissel et al 1980 mcadoo and sandwell 1985 in the area the calculated stress field in the area adjacent to the southeast and central india ridges is characterized by tension parallel to the spreading axis this explains the concentration of near ridge normal faulting seismicity with t axes subparaile1 to the spreading ridge in the indian ocean as recently observed by bergman et al 1984 and wiens and stein 1984 the regional stress field along the strike of the sunda arc varies from compression seaward of and parallel to the sumatra trench segment to tension perpendicular to the java flores segment this explains the selective occurrence of well developed grabens seaward off the java flores segment of the trench observed by hilde 1983 our modelling shows that the observed rotation of the stress field denham et al 1979 in the australian continent is mainly the consequence of its geographic position relative to the surrounding trench segments and the variations of the forces acting on the down going slab in each of these the state of compression in west and central australia is induced by the action of resistive forces at the himalayan and banda arc collision zones the joint occurrence of high levels of compression in the plate s interior and normal faulting seismicity in the near ridge areas is a transient feature unique to the present dynamic situation of the indo australian plate

modification of the lithospheric stress field by lateral variations in plate mantle coupling 1 the presence of deeply penetrating continental roots may locally increase the magnitude of basal shear tractions by up to a factor of 4 compared to a layered viscosity structure here we examine how these increases in mantle lithosphere coupling influence stress patterns in the overlying elastic lithosphere by coupling a mantle flow model to a model for the elastic lithosphere we show that the amplification of mantle tractions beneath cratons increases elastic stress magnitudes by at most a factor of only 1 5 in a pattern not correlated to local basal traction changes this disconnect is explained by the transmission of elastic stresses across large distances which makes them sensitive to regionally averaged changes in basal tractions but not local variations our results highlight the importance of regional variations in lithospheric strength which could allow stress patterns to more closely match regional changes in basal shear

ridge forces absolute plate motions and the intraplate stress field torque poles are calculated for a variety of possible forces acting on the plates including ridge push slab pull and collisional resistance these torque poles are then compared to the directions of absolute plate motions there is a strong correlation between ridge torque poles and the azimuth of absolute plate motions for the north american south american pacific cocos and eurasian plates simple slab pull torques correlate well with absolute motion azimuths for the pacific nazca and cocos plates and moderately well with the absolute motion azimuth of the indoaustralian plate collisional resistance torque poles correlate with the absolute motion azimuth of the eurasian plate only the correlations are presented as further evidence that the absolute reference frame for plate motion is determined by the surface plates themselves torque poles for various forces are also compared with several long wavelength features of the global intraplate stress field that also tend to be aligned with absolute motion directions in general ridge torque directions agree well with the orientations of maximum horizontal stresses for stable north america western europe and south america and provide an alternative explanation for the alignment in terms of ridge push forces rather than basal drag collisional resistance forces can also explain the alignment of stresses in western europe for the indoaustralian plate the torque pole for collisional resistance forces is consistent with the general pattern of stresses in at least the western half of the plate but is not a good predictor of the entire data set for the plate other processes in addition to collisional resistance must be important for the indo australian plate ridge push forces may account for a significant portion of the long wavelength features of the intraplate stress field especially away from continental collisions such a conclusion is consistent with negative buoyancy of the slab being an important component of the driving mechanism as previously suggested slab forces may be largely balanced within the subducted slab itself and thus have limited effect on deformation of the surface plates

andersonian wrench faulting in a regional stress field during the 2010 2011 canterbury new zealand earthquake sequence the initial mw7 1 darfield earthquake sequence was centred west of christchurch city in the south island of new zealand but aftershocks including a highly destructive mw6 3 event eventually extended eastwards across the city to the coast the mainshock gave rise to right lateral strike slip of up to 5 m along the segmented rupture trace of a subvertical fault trending 085 58 across the canterbury plains for c 30 km in agreement with teleseismic focal mechan isms near field data however suggest that the mainshock was composite initiating with reverse slip north of the surface rupture stress determinations for the central south island show maximum compressive stress s1 to be horizontal and oriented 115 58 the principal dextral rupture there fore lies at c 3 08 to regional s1 the classic andersonian orientation for a low displacement wrench fault an aftershock lineament trending c 1458 possibly represents a conjugate left lateral strike slip structure this stress field is also consistent with predominantly reverse slip reactivation of nne ne faults along the southern alps range front the main strike slip fault appears to have a low cumulative displacement and may represent either a fairly newly formed fault in the regional stress field or an existing subvertical fault that happens to be optimally oriented for frictional reactivation

present and past soil erosion rates in catchments of the kraichgau area sw germany abstract in four catchments of the kraichgau area sw germany all covered with loess and distinguished by different combinations of natural and manmade erosion risks total and recent soil losses from the hills were examined the total loss was calculated as difference of quantities of soil material of the mapped soil units compared with a profile under erosion protection the recent loss on the basis of young sediments in the depression using contents of cadmium and lead to distinguish between old and young soil deposits in the depressions in two of the catchments total soil loss from the hills came up to about 90 of the formerly existing luvisol material total soil loss did not correlate with the natural erosion risks inclination slope length but recent soil loss correlated with the manmade erosion risks land utilisation type this recent soil loss ranged from less than 14 t ha 1 yr 1 in the catchment with terraced slopes to 84 t ha 1 yr 1 in a catchment with a high percentage of corn and sugar beet on the cultivated area and with large fields cultivated downslope in a similarly endowed catchment but with transversally cultivated fields a recent soil erosion of 39 t ha 1 yr 1 was calculated methodical problems are discussed

historical soil erosion by water in germany scales and archives chronology research perspectives abstract the published record of historical soil erosion by water in germany as deduced from dated slope deposits n 306 alluvial sediments n 120 and lake sediments is summarized in this paper the number of sediments investigated reflects the state of knowledge chronology of historical soil erosion and to a certain degree the intensity of the human impact on german landscapes during the holocene even though few data of calculated historical soil erosion intensities exist an estimation of historical soil erosion in germany combining the available data has been calculated soil erosion in germany occurred first locally during the early holocene probably triggered by climatic variability from the neolithic onward the record reflects the human impact according to agricultural land use the observed variability indicates phases of weaker and regained intensity of agricultural land use in germany few records characterise the early and middle bronze age ca 2000 1600 bc and the migration period and the early medieval times ca 400 1000 ad surprisingly for the roman emperor times ca 1 400 ad a decreasing number of soil sediments is recorded even when the data from southern germany is examined separately phases characterised by an increase in soil erosion were the late bronze age and pre roman iron age ca 1600 bc 1 ad the high and late medieval times ca 1000 1350 ad and the modern times ca 1500 ad until today some extraordinary heavy precipitation events late 18th early 19th first half of 14th century pre roman iron age topped the even high soil erosion intensities research gaps as well as potential for future research as derived from the available data are outlined

present day stress orientation in brunei a snapshot of prograding tectonics in a tertiary delta the baram delta province of nw borneo is unusual when compared with most other tertiary deltas as it has built up upon an active margin hence structures observed in the baram delta province are the result of both margin parallel gravity driven deltaic tectonics and approximately margin normal transpressive tectonics associated with the active margin image and dipmeter logs have been examined for breakouts and drilling induced tensile fractures ditfs in 47 wells throughout brunei breakouts and ditfs observed in 19 wells suggest that the maximum horizontal stress is oriented margin normal nw se in the proximal parts of the basin and margin parallel ne sw in the outer shelf region the margin parallel outer shelf stress field is interpreted as a local deltaic stress field caused by the shape of the clastic wedge the margin normal maximum horizontal stress in the inner shelf is interpreted to reflect basement stresses associated with the active margin however the maximum horizontal stress in the inner shelf is approximately perpendicular to the strike of miocene pliocene normal growth faults suggesting that maximum horizontal stress in the inner shelf has rotated from margin parallel deltaic to margin normal basement associated over time hence approximately the same stress rotation has occurred over time in the inner shelf as is currently observed spatially from the outer to inner shelf the spatial and temporal stress rotations in brunei are thus interpreted to be the result of deltaic and basement associated tectonic regimes that are prograding basin wards the proximity of the active margin has resulted in progressive uplift and inversion of the hinterland that has forced the delta system to prograde rapidly the zone of active deltaic growth faulting and margin parallel maximum horizontal stress has shifted basin wards prograded as the delta system has rapidly prograded across the shelf after uplift and delta progradation the old growth faults of the inner shelf ceased being active and have then been successively reactivated by a similarly prograding margin normal inversion front

joint modeling of lithosphere and mantle dynamics elucidating lithosphere mantle coupling 1 we provide new insights into the lithosphere mantle coupling problem through a joint modeling of lithosphere dynamics and mantle convection and through comparison of model results with the high resolution velocity gradient tensor model along the earth s plate boundary zones using a laterally variable effective viscosity lithosphere model we compute depth integrated deviatoric stresses associated with both gravitational potential energy gpe differences and deeper mantle density buoyancy driven convection when deviatoric stresses from horizontal basal tractions associated with deeper density buoyancy driven convective circulation of the mantle are added to those from gpe differences the fit between the model deviatoric stress field and the deformation indicators improves dramatically in most areas of continental deformation we find that the stresses induced by the horizontal tractions arising from deep mantle convection contribute approximately 50 of the magnitude of the earth s deviatoric lithospheric stress field we also demonstrate that lithosphere asthenosphere viscosity contrasts and lateral variations within the lithospheric plate boundary zones play an important role in generating the right direction and magnitude of tractions that yield an optimal match between deviatoric stress tensor patterns and the deformation indicators

teleseismic investigation of the january 22 1988 tennant creek australia earthquakes the three january 22 1988 earthquakes are the largest to occur within the australian continent in 20 years and produced two colinear but discontinuous wnw trending scarps enclosing a shorter ene trending scarp teleseismic long period p and sh and short period p waves are used to constrain the locations and source parameters for the three events the third earthquake has a seismic moment 1019nm equal to that of the 1968 meckering event and most likely ruptured the southern of the wnw trending faults relative relocations suggest that the two smaller earthquakes initiated north or nw of the third event centroid depths are less than 6 km but most likely 3 to 4 km and source durations are 4 to 6s so it is probable that each event broke the surface all three earthquakes have predominantly thrust mechanisms and nodal planes that strike west to wnw consistent with faults dipping southward at 30 to 40 only the first has a nodal plane that could support a north dip for the ene trending fault as proposed by other researchers on the basis of ground deformation and preliminary aftershock locations however source directivity evident in the short period p waves and relocations are interpreted better if this event like the others ruptured a sw dipping fault plane the ene trending scarp is interpreted to be a tear fault in the hanging wall that may have acted as a barrier to slip on a single continuous sw dipping fault resulting in this unusual at least for australia sequence of three large similar earthquakes

effects of density contrasts on the orientation of stresses in the lithosphere relation to principal stress directions in the transverse ranges california the influence of stresses arising from horizontal density contrasts on the orientation and relative magnitudes of principal stresses in an otherwise uniform lithospheric stress field is investigated a simple model is constructed in which a local deviatoric stress due to a density anomaly embedded within or just below the lithosphere and a regionally constant deviatoric stress field are each approximated by biaxial tensors the net stress field is obtained from the sum of the two both the relative magnitudes of principal stresses and the magnitude of the angular difference in principal stress direction of the summed tensor compared with that obtained in the absence of buoyancy forces depend on two parameters the first is the ratio where is a measure of the magnitude of the regional deviatoric stress and is the magnitude of the stress arising from buoyancy forces associated with the density anomaly the second parameter is the angle between the trend of the density anomaly and the direction of maximum compressional stress that obtains in the absence of any perturbation by the local buoyancy forces the directions of the principal axes of the total stress field are found to differ by up to 90 from those of the reference stress field the model is applied to the transverse ranges california where the observed 23 difference in orientation of principal horizontal compressive stress compared with the principal compressive stress direction in central california constrains the predicted value of to be approximately 0 4 this is consistent with an independently calculated range of in which is inferred from seismological constraints on the magnitude of density variations underneath the transverse ranges and is inferred from observations of heat flow along the san andreas fault in central california the agreement between the two estimates of supports the hypothesis that the observed differences in horizontal principal stress orientation in california can be explained by the combined influence of a local negative buoyancy force under the transverse ranges and a regional stress field associated with transcurrent deformation within the pacific north american plate boundary zone the observed counterclockwise angular difference in principal horizontal stress direction in the transverse ranges compared with central california implies that the plane of maximum right lateral shear stress is also rotated counterclockwise relative to that in central california this supports the possibility that the big bend in the san andreas fault may be a consequence of the negative buoyancy forces acting in the transverse ranges and not the cause of transverse ranges formation as has often been assumed

predicting the lithospheric stress field and plate motions by joint modeling of lithosphere and mantle dynamics the way in which basal tractions associated with mantle convection couples with the lithosphere is a fundamental problem in geodynamics a successful lithosphere mantle coupling model for the earth will satisfy observations of plate motions intraplate stresses and the plate boundary zone deformation we solve the depth integrated three dimensional force balance equations in a global finite element model that takes into account effects of both topography and shallow lithosphere structure as well as tractions originating from deeper mantle convection the contribution from topography and lithosphere structure is estimated by calculating gravitational potential energy differences the basal tractions are derived from a fully dynamic flow model with both radial and lateral viscosity variations we simultaneously fit stresses and plate motions in order to delineate a best fit lithosphere mantle coupling model we use both the world stress map and the global strain rate model to constrain the models we find that a strongly coupled model with a stiff lithosphere and 3 4 orders of lateral viscosity variations in the lithosphere are best able to match the observational constraints our predicted deviatoric stresses which are dominated by contribution from mantle tractions range between 20 70 mpa the best fitting coupled models predict strain rates that are consistent with observations that is the intraplate areas are nearly rigid whereas plate boundaries and some other continental deformation zones display high strain rates comparison of mantle tractions and surface velocities indicate that in most areas tractions are driving although in a few regions including western north america tractions are resistive citation ghosh a w e holt and l m wen 2013 predicting the lithospheric stress field and plate motions by joint modeling of lithosphere and mantle dynamics

influence of basement structures on in situ stresses over the surat basin southeast queensland the jurassic to cretaceous sedimentary rocks of the surat basin in southeast queensland host a significant volume of coal seam gas resources consequently knowledge of the in situ stress is important for coal permeability enhancement and wellbore stability using wireline log data and direct stress measurements we have calculated stress orientations from 36 wells and stress magnitudes from 7 wells across the surat basin our results reveal a relationship between high tectonic stress and proximity to structures within the underlying basement rocks the influence of tectonic stresses is diminished with depth in areas with thicker sedimentary cover that are relatively far from the basement structures we suggest that this relationship is due to the redistribution of in situ stresses around areas where basement is shallower and where basement structures such as the leichhardt burunga fault system are present this behavior is explained by a lower rigidity in the thickest basin cover which reduces the ability to maintain higher tectonic stress over the entire surat basin a significant amount of variability in in situ stress orientation is observed the authors attribute this stress variability to complex plate boundary interactions on the northern and eastern margins of the indo australian plate

pedosedimentary and geoarcheological archives from clay dominated sinkhole infillings in middle franconia germany abstract sinkholes in the karstified middle keuper gypsum of middle franconia germany reveal numerous archeological findings and contain unique pedosedimentary records of landscape development and human environment interaction during the holocene mudstone derived high clay contents result in a unique set of sedimentary and pedogenic properties of these archives in that all units exhibit vertic properties since the horizons have a polygenic history detailed field and micromorphological observations together with laboratory analyses grain size color iron pedochemistry are the basis for a classification of the pedosediments 14c dating provides a chronological framework for geomorphological stability phases and thus identified soil forming processes the first anthropogenic colluvial sediments of the studied archive date to the early bronze age and accumulated in an initial karst depression water saturation caused iron reduction of these early infillings in the pedosediments above oxidation and iron release are largely related to changes in the parent material here the soil material contains coarse silt indicating an admixture of nearby periglacial slope deposits furthermore fossil root traces point to a longer time with stable conditions which we interpret as absence of humans or at least an extended period of fallow land the superimposed sediments from the urnfield period are more inhomogeneous and consist of material from the eroded agricultural soils of the surrounding the characteristics of these pedosediments point to intensified human land use pedogenic processes such as iron release reduction of iron swelling shrinking and short distance translocation of clay intensively overprinted all soil sediments in this context micromorphology proved to be an essential tool for the characterization of polygenesis in terms of soil forming as well as redepositional processes that lead to the formation of these complex archives the present study reflects a multi methodological approach to a rather disregarded type of polygenic terrestrial records it constitutes an example for the investigation of clayey pedosediments in karstic environments under moderate climate in the frame of a prehistoric geoarcheological setting

spatial delineation of organic carbon rich colluvial soils in chernozem regions by terrain analysis and fuzzy classification abstract colluvial soils are considered to be the direct result of accelerated soil erosion resulting in accumulation of humus rich soil material in terrain depressions and base parts of slopes the organic carbon concentration in these soils and their depth make them an important organic carbon storage mapping the colluvial soils therefore represents an important contribution in total carbon stock estimation a method of delineating colluvial soils is proposed by applying a combination of high resolution digital elevation model analysis and detailed field survey two models based on fuzzy classification of soil units were created using different topographic derivatives as the only input parameters to predict the colluvial soil area on a morphologically diverse study site in the southern moravia czech republic the model that considers only the derivatives with a strong relationship to colluvial soil occurrence reached 71 accuracy in colluvial area delineation while the model combining six commonly used derivatives showed less favorable results the main advantage of the method lies in a low demand of input soil data and its relatively high accuracy

subsurface fracture analysis and determination of in situ stress direction using fmi logs an example from the santonian carbonates ilam formation in the abadan plain iran abstract the relationship between the present day stress field and natural fractures can have significant implications for subsurface fluid flow in particular fractures that are aligned in orientations favourable for reactivation by either shear or tensile failure in the in situ stress field often exhibit higher hydraulic conductivities the ilam formation of southwestern iran is an important hydrocarbon reservoir containing numerous natural fractures however little is known about the state of stress in this region or any of iran s petroleum provinces we conducted analysis of the present day maximum horizontal stress orientation and the density orientation and hydraulic conductivity of natural fractures in the ilam carbonates using high resolution formation micro imager resistivity logs in two wells a total of 51 breakouts with an overall length of 215 m were observed in the two wells indicating a maximum horizontal stress orientation of 68 n 7 6 in well a and 58 n 6 3 in well b furthermore the wellbore derived stress orientations determined herein are consistent with those inferred from nearby earthquake focal mechanism solutions indicating that stresses in the sedimentary cover are linked to the resistance forces generated by arabia eurasia collision furthermore the correlation between stress orientations estimated from earthquake focal mechanism solutions and breakouts indicates that focal mechanism solution data which is often considered to be unreliable for stress field analysis near transform margins may provide reliable information on the stress orientation near continental collision zones the image log data also reveals three sets of open and presumably hydraulically conductive fractures with strikes of i 160 170 n ii 110 140 n and iii 070 080 n fracture set iii is consistent with being formed and open in the present day stress field however fracture sets i and ii strike at a high angle to the present day maximum horizontal stress and are interpreted herein to be the result of either pre or syn folding related forces the observation that different sets of open fractures in the field can be either sensitive or insensitive to the present day stress is critical for improving hydrocarbon recovery

the in situ stress field of the perth basin australia a total of 17 wells in the perth basin were interpreted to have 114 breakouts covering a combined length of 3 2 km and a mean hmax orientation of 108 n the inferred mean orientation of hmax in the perth basin is broadly consistent with that in the adjacent basement yilgarn block the new data confirm that hmax orientation in the region is consistent with other stress indicators different depths and different geological provinces the new data also confirm that the orientation of hmax does not parallel the nne direction of absolute plate velocity anomalous north south hmax orientations identified in a number of wells in the perth basin can be attributed to local structural effects

global azimuthal seismic anisotropy and the unique plate motion deformation of australia differences in the thickness of the high velocity lid underlying continents as imaged by seismic tomography have fuelled a long debate on the origin of the roots of continents1 2 3 4 5 some of these differences may be reconciled by observations of radial anisotropy between 250 and 300 km depth with horizontally polarized shear waves travelling faster than vertically polarized ones2 this azimuthally averaged anisotropy could arise from present day deformation at the base of the plate as has been found for shallower depths beneath ocean basins6 such deformation would also produce significant azimuthal variation owing to the preferred alignment of highly anisotropic minerals7 here we report global observations of surface wave azimuthal anisotropy which indicate that only the continental portion of the australian plate displays significant azimuthal anisotropy and strong correlation with present day plate motion in the depth range 175 300 km beneath other continents azimuthal anisotropy is only weakly correlated with plate motion and its depth location is similar to that found beneath oceans we infer that the fast moving australian plate contains the only continental region with a sufficiently large deformation at its base to be transformed into azimuthal anisotropy simple shear leading to anisotropy with a plunging axis of symmetry may explain the smaller azimuthal anisotropy beneath other continents

statistical trends in the intraplate stress field the world stress map wsm database contains thousands of intraplate stress indicators with the potential to provide important constraint for arguments about the relationship between tectonic stresses and both the kinematics and dynamics of plate motion previous studies which relied almost exclusively on visual inspection of the data established the existence of broad regions of uniform maximum horizontal compressive stress orientation shmax and stress regimes on a regional scale in the present study we present a statistical analysis of the wsm stress indicators with the aim of quantifying trends in both the shmax orientations and stress regimes the analysis was carried out within 5 5 bins which provide a resolution of several hundred kilometers only the 4537 high quality wsm indicators with rating of a to c were used in the analysis we present results for two types of analysis on the information contained within the bins first we evaluate the spatial distribution of the average stress regime normal strike slip or thrust second we apply the rayleigh test a standard statistical method in the analysis of directional data to the distribution of shmax orientations to test the null hypothesis that the orientations are random an important aspect of our study is the quantification of the conclusions drawn from visual inspection of the world stress map our results indicate that broad regions of uniform shmax orientations exist in most continental regions at high confidence levels 90 and 95 and are less robust in the slowest moving continental plates we also quantify the predominance of strike slip and compressional stress regimes in continental regions importantly our analysis provides information about trends in the shmax orientations in regions where large amounts of scatter in the directional data prevented conclusions being drawn from visual inspection of the data for example in western north america and continental australia furthermore we find a strong correlation between average shmax orientations and both the ridge push torque and the absolute plate velocity azimuths our observation that a greater number of shmax orientations correlate with the ridge push torque directions is further evidence that the intraplate stress field is strongly influenced by the ridge push force

a record of stable continental region earthquakes from western australia spanning the late pleistocene insights for contemporary seismicity abstract in plate boundary regions moderate to large earthquakes are often sufficiently frequent that fundamental seismic parameters such as the recurrence intervals of large earthquakes and maximum credible earthquake mmax can be estimated with some degree of confidence the same is not true for the stable continental regions scrs of the world large earthquakes are so infrequent that the data distributions upon which recurrence and mmax estimates are based are heavily skewed towards magnitudes below m w 5 0 and so require significant extrapolation up to magnitudes for which the most damaging ground shaking might be expected the rarity of validating evidence from surface rupturing palaeo earthquakes typically limits the confidence with which these extrapolated statistical parameters may be applied herein we present a new earthquake catalogue containing in addition to the historic record of seismicity 150 palaeo earthquakes derived from 60 palaeo earthquake features spanning the last 100 ka of the history of the precambrian shield and fringing extended margin of southwest western australia from this combined dataset we show that mmax in non extended scr is m7 25 0 1 and in extended scr is m7 65 0 1 we also demonstrate that in the 230 000 km 2 area of non extended scr crust the rate of seismic activity required to build these scarps is one tenth of the contemporary seismicity in the area consistent with episodic or clustered models describing scr earthquake recurrence a dominance in the landscape of earthquake scarps reflecting multiple events suggests that the largest earthquakes are likely to occur on pre existing faults we expect these results might apply to most areas of non extended scr worldwide

topography boundary forces and the indo australian intraplate stress field the relative contribution of topographic e g ridge push continental margins and elevated continental crust and plate boundary e g subduction and collisional forces to the intraplate stress field in the indo australian plate iap is evaluated through a finite element analysis two important aspects of the iap intraplate stress field are highlighted in the present study 1 if substantial focusing of the ridge push torque occurs along the collisional boundaries i e himalaya new guinea and new zealand many of the first order features of the observed stress field can be explained without appealing to either subduction or basal drag forces and 2 it is possible to fit the observed shmax maximum horizontal stress orientation and stress regime information with a set of boundary conditions that results in low tectonic stress magnitudes e g tens of megapascals averaged over the thickness of the lithosphere throughout the plate this study therefore presents a plausible alternative to previous studies of the iap intraplate stress field which predicted very large tectonic stress magnitudes hundreds of megapascals in some parts of the plate in addition topographic forces due to continental margins and elevated continental material were found to play an important role in the predicted stress fields of continental india and australia and the inclusion of these forces in the modeling produced a significant improvement in the fit of the predicted intraplate stresses to the available observed stress information in these continental regions a central focus of this study is the relative importance of the boundary conditions used to represent forces acting along the northern plate margin we note that a wide range of boundary conditions can be configured to match the large portion of the observed intraplate stress field and this nonuniqueness continues to make modeling the iap stress field problematic while our study is an important step forward in understanding the sources of the iap intraplate stress field a more complete understanding awaits a better understanding of the relative magnitude of the boundary forces acting along the northern plate margin

sv wave azimuthal anisotropy in the australian upper mantle preliminary results from automated rayleigh waveform inversion summary the pattern of azimuthal anisotropy for sv waves in the upper mantle beneath australia has been determined using a two stage tomographic procedure for rayleigh waves the inversion exploits an automated procedure based on the waveform inversion method of cara leve que 1987 to allow the analysis of 668 vertical component seismograms within a few weeks the automated procedure provides an eiective choice of the secondary observables used in the waveform inversion for both fundamental and higher modes allowing the construction of a set of radially strati ed upper mantle models which represent the average structures on paths criss crossing the australian continent the 668 path average models are then combined in a 3 d velocity model which describes the lateral variation of the sv velocity and its azimuthal anisotropy the lateral variations in wave speed show a good overall agreement with previous results for shear wave speed variations in australia but are accompanied by signi cant azimuthal anisotropy at 150 km depth the anisotropy displays a simple pattern with most of the directions of fast sv velocities dominated by a north south component close to the present day absolute plate motion nevertheless in the regions with the highest shear wave speed anisotropy is not aligned with the current plate motion suggesting a local resistance to mantle ow

a revised crustal stress orientation database for canada abstract the canadian database on contemporary crustal stress has not been revised systematically in the past two decades here we present the results of our new compilation that contains 514 new data records for the orientation data of maximum compressive horizontal stress and 188 data records that were re assessed in total the canadian stress database has now 1667 data records which is an increase of about 45 from these data a new canadian stress map as well as one for the province of alberta is presented to analyse the stress pattern we use the quasi median on the circle as a smoothing algorithm that generates a smoothed stress map of the maximum compressive horizontal stress orientation on a regular grid the newly introduced quasi interquartile range on the circle estimates the spreading of the data and is used as a measure for the wave length of the stress pattern the result of the hybrid wavelength analysis confirms that long spatial wavelength stress patterns 1000 km exist in large areas in canada the observed stress pattern is transmitted through the intra plate regions the results reveal that shorter spatial wave length variation of the maximum compressive horizontal stress orientation of less than 200 km prevails particularly in south eastern and western canada regional stress sources such as density contrasts active fault systems crustal structures etc might have a significant impact in these regions in contrast to these variations the observed stress pattern in the alberta basin is very homogeneous and mainly controlled by plate boundary forces and body forces the influence of curvature of the rocky mountains salient in southern alberta is minimal the present day horizontal stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the alberta basin

plate motions and stresses from global dynamic models delineating the driving forces behind plate motions is important for understanding the processes that have shaped earth throughout its history however the accurate prediction of plate motions boundary zone deformation rigidity and stresses remains a difficult frontier in numerical modeling we present a global dynamic model that produces a good fit to such parameters by accounting for lateral viscosity variations in the top 200 kilometers of earth together with forces associated with topography and lithosphere structure as well as coupling with mantle flow the relative importance of shallow structure versus deeper mantle flow varies over earth s surface our model reveals where mantle flow contributes toward driving or resisting plate motions furthermore subducted slabs need not act as strong stress guides to satisfy global observations of plate motions and stress

slip rate variability and distributed deformation in the marmara sea fault system the slip rate along a fault controls the accumulation of strain that is eventually released during an earthquake estimates from a three dimensional geomechanical model of the slip rate on the main marmara fault near istanbul turkey reconcile geodetic and geological observations and indicate smaller values and higher variability than previously thought the slip rate along a fault controls the accumulation of strain that is eventually released during an earthquake1 along a 150 km long stretch of the north anatolian fault near istanbul turkey strain has been building up2 since the last large earthquake in 1766 estimates of the geodetic slip rates along the main marmara fault vary widely ranging between 17 and 27 9 mm yr 1 refs 2 3 4 5 this slip rate is difficult to quantify because of the lack of satellite observations offshore and the complexity of the submarine fault system that includes the main marmara fault2 6 7 here we estimate the right lateral slip rate on the main marmara fault using a three dimensional geomechanical model that incorporates these structural complexities from our simulations we infer slip rates between 12 8 and 17 8 mm yr 1 our estimates are smaller and more variable than previous results primarily because of slip partitioning and internal deformation our model results reconcile geodetic observations and geological fault slip rates8 9 10 which had been considered conflicting previously we suggest that the inferred variability in slip rate on the main marmara fault favours segmented release of seismic moment during consecutive events over the failure of the whole seismic gap in one large earthquake

buried paleosols in balks of kalmykiya as a record of late holocene nature and society interaction abstract modern and buried soils under valley sediments have been compared on the southern russian plain kalmykiya in the arid zone the buried soil contains more humus and less carbonates and ph values are lower the humus content in this soil is comparable with that of modern haplic kastanozems and gleyic phaeozems the comparison of differences in properties of buried soil at specific times and historical data on cultures functioning in these periods has allowed us to reveal the interrelation of nature and society processes development in south kalmykia since the middle holocene three stages of landscape development are recognized 1 stable stage at least 3000 years long from the 2nd millennium bc until the 1st millennium ad characterized by the formation of meadow steppe soils 2 dynamic stage likely short when deposits were accumulated and soils were buried and 3 modern stable stage at least 500 years long up to the present time characterized by the formation of meadow saline soils molli endogleyic solonetz on deposits in valleys a strong ecological crisis was evident in the territory of modern kalmykia about 1000 years ago resulting from the collapse of the khazar state as a result meadow steppe soils were buried and saline molli endogleyic soils were formed

large scale lithospheric stress field and topography induced by global mantle circulation stresses in the lithosphere are one indication of processes in the earth interior here we present a calculation of largescale lithospheric stresses caused by global mantle circulation the mantle flow field is calculated based on density structures inferred from global seismic tomography predicted principal stress directions are compared to interpolations based on observed stresses agreement between predictions and observations is often good in regions where lithospheric stresses and mantle tomography are well constrained predicted magnitudes of scalar stress anomalies vary more strongly than predicted stress directions for various tomographic models hotspots preferentially occur in regions where calculated stress anomalies are tensile or slightly compressive results do not strongly depend on radial mantle viscosity structure lithospheric rheology viscous or elastic or plate motion model the model also predicts the directions of motion well for most plates misfits in the predicted magnitudes can be explained qualitatively stress anomalies due to causes within the lithosphere oceanic cooling with age variations in crustal thickness topography isostatically compensated at subcrustal levels are also computed predicted stress directions in the absence of mantle flow can explain observations almost as well as mantle flow nevertheless current models of mantle flow are largely in accord with interpolations of observed principal stress directions and the observed plate motions fl 2001 elsevier science b v all rights reserved

regional stress field of the indian plate we have calculated the regional stress field in the indian plate implementing dependence of slab pull and ridge push on the age of the oceanic lithosphere in the finite element procedure the high level of the calculated stress field order of a few kbar and the dominance of compression in the plate are consequences of the unique dynamic situation of the present day indian plate the calculated stress field explains the concentration of intraplate deformation in the region of the ninetyeast ridge and yields insight into the variations in stress directions in the australian continent

holocene relief and soil changes in loess covered areas of south western germany the pedosedimentary archives of bretten bauerbach kraichgau based on infrared stimulated luminescence irsl dating of loess borne sediments a chronometry of holocene landscape evolution is established for a representative study site in the early settled kraichgau area in south western germany the results show that the gently rolling relief is due essentially to soil erosion and colluvial deposition triggered by humans cultivating the loess soils since the onset of agriculture in the neolithic period levelling of relief is accompanied by alterations in soil type patterns from haplic luvisols before the impact of humans over variably truncated luvisols with bt horizons prevailing at the slope surfaces in the middle ages to calcaric regosols characterizing both sites of erosion and accumulation since then the tremendous changes show that the effects of human activities have been recorded over thousands of years indicating an early anthropocene in a geomorphological and pedological sense most landscapes are probably more modified by humans than thought at first sight as the results show this recognition requires considering that current geomorphological and soil forming processes might work at different frequencies or magnitudes e g by changes of internal system thresholds such as increased erodibility following the complete erosion of a more resistant bt horizon and or in a different direction e g accumulation instead of erosion or sediment transport due to slope angles decreased by former deposition of colluvium than they would in the absence of a human controlled pre history

localization of intraplate deformation through fluid assisted faulting in the lower crust the flinders ranges south australia abstract in this paper we present a hypothesis for localized intraplate deformation in the continental crust of south central australia that involves fluid assisted reactivation of faults in the mid to lower crust using data from a temporary seismometer deployment in the flinders ranges we show that earthquakes relocated in a 3d velocity model cluster in elongated low vp vs anomalies that extend to depths exceeding 20 km and are aligned with the axis of the flinders ranges in the northern flinders ranges these low vp vs anomalies can be interpreted as fractured neoproterozoic to cambrian sediments that separate two cratonic blocks the gawler craton to the west and the curnamona province in the east previous studies of helium isotopes in springs to the north of the area provide evidence of mantle derived fluids that may influence faulting at depth our focal mechanism and stress inversion results show a regionally compressive stress field that provides no evidence for stress concentration we also argue that mechanisms for localized faulting such as thermal weakening and isostatic rebound also fail to account for the occurrence of earthquakes at mid to lower crustal depth in this area of high heat flow and that the focused seismicity can only be explained by high pore fluid pressure in the lower crust

gravitational potential energy and active deformation in the apennines we use velocity measurements from a network of continuous gps sites spanning the apennines of peninsular italy to test the hypothesis that the active deformation of the region is explained by variations in gravitational potential energy of the lithosphere the simple geometry of the mountain chain allows us to treat the deformation as two dimensional neglecting gradients of velocity along the strike of the chain under this assumption the integral of gravitational potential energy per unit area of the lithosphere gpe in the direction perpendicular to the chain is related by a simple expression to the velocity in the same direction we show that the observed velocities match this expression with an rms misfit of 0 5mm yr this agreement suggests that deformation of the apennines reflects a balance within the mountain chain itself between lateral variations in gpe and the stresses required to deform the lithosphere forces arising from processes external to the belt are not required to explain the observations

australia s large earthquakes and recent fault scarps abstract nineteen large earthquakes up to magnitude ms 6 8 have occurred within continental australia this century and at least seven recent prehistoric fault scarps have been discovered the magnitude of the earthquake causing each of these prehistoric fault scarps has been estimated from the observed fault length and maximum scarp height and none exeeds magnitude 7 0 their occurrence demonstrates that the australian plate is undergoing significant internal deformation but as yet there is no model to explain their cause nor the likely site of the next large earthquake the absence of earthquake epicentres on the current tectonic map of australia is a regrettable omission

inferring stress from faulting from early concepts to inverse methods abstract we review the evolution of concepts on and methods of estimating the state of stress from fault movements theories of failure in isotropic materials suggested a simple geometrical construction of optimal principal stress directions from a fault plane and its associated slip these optimal directions align shear stress and slip directions and maximize the difference between shear stress and frictional resistance on the fault plane optimal stress directions for calcite twinning are obtained by a similar construction with the difference that they maximize shear stress force representation of seismic sources independently introduced pressure p and tension t axes at positions that also maximize shear stress on both nodal planes frictional slip theory and the constraint that slip and shear stress directions be parallel allowed to address reactivation of pre existing faults this suggested that stress could also be inverted from reactivated fault and slip data or earthquake focal mechanisms early methods relied on geometrical constructions as a substitute for calculations whereas later methods relied on software as these calculations became tractable with the help of computers similar methods were developed for the inversion of stress from crystal twin gliding with non optimal geometry with a different criterion that relies on a threshold of the component of shear stress along the gliding line even though these methods seek a common stress tensor compatible with fault and slip data their main use is to separate polyphase data into homogeneous subsets and help deciphering complex tectonic histories fault and slip data can also be analyzed to constrain the strain rather than the stress tensor in most cases this involves a summation and yields an average strain for the considered rock volume stress inversion thus appears better suited for differentiating heterogeneous data whereas strain analysis appears better suited for homogenizing them

regional patterns of tectonic stress in europe nearly 1500 stress orientation determinations are now available for europe the data come from earthquake focal mechanisms overcoring measurements well bore breakouts hydraulic fracturing measurements and young fault slip studies and sample the stress field from the surface to seismogenic depths three distinct regional patterns of maximum compressive horizontal stress shmax orientation can be defined from these data a consistent nw to nnw shmax stress orientation in western europe a wnw ese shmax orientation in scandinavia similar to western europe but with a larger variability of shmax orientations and a consistent e w shmax orientation and n s extension in the aegean sea and western anatolia the different stress fields can be attributed to plate driving forces acting on the boundaries of the eurasian plate locally modified by lithospheric properties in different regions on average the orientation of maximum stress in western europe is subparallel to the direction of relative plate motion between africa and europe and is rotated 17 clockwise from the direction of absolute plate motion the uniformly oriented stress field in western europe coincides with thin to medium lithospheric thickness approximately 50 90 km and high heat flow values 80 m w m2 in western europe a predominance of strike slip focal mechanisms implies that the intermediate principal stress is vertical the more irregular horizontal stress orientations in scandinavia coincide with thick continental lithosphere 110 170 km and low heat flow 50 m w m2 the cold thick lithosphere in this region may result in lower mean stresses associated with far field tectonic forces and allow the stress field to be more easily perturbed by local effects such as deglaciation flexure and topography the stress field of the aegean sea and western anatolia is consistent with n s extension in a back arc setting behind the hellenic trench subduction zone the stress field is influenced in places by regional geologic structures e g in the western alps where shmax directions show a slight tendency toward a radial stress pattern not all major geologic structures however appear to affect the shmax orientation e g in the vicinity of the rhine rift system horizontal stress orientations are continuous

stress orientations found in north east germany differ from the west european trend knowledge about the acting stresses is of crucial importance for understanding the tectonics of a region data about the stress field in north eastern germany used to be very rare in general it was assumed that the orientation of the larger horizontal principal stress sh is similar to that found for western germany and central west europe i e nw se to check this several borehole logs of the late 1980s were analysed for information on the principal horizontal stress orientations they include four arm dipmeter and borehole televiewer data from 15 boreholes the depth range of our stress results reaches from 1500 to 6700 m they were compared to a few other data especially from hydraulic fracturing and to recent findings on the stresses in the northwest german basin in contrast to expectation sh derived from breakout orientations below the salt layers displayed n to ne orientation the latter was found at 10 locations spread over the ne german basin from berlin to the baltic sea from the polish border to the former border between east and west germany moreover this stress rotation in the subsaline formations seems to be the continuation of a trend found in the nw german basin

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