on late miocene to recent vertical motions in the cretan segment of the hellenic arc abstract high resolution foraminiferal and calcareous nannoplankton biostratigraphy and reliable paleobathymetry estimates based on plankton benthos ratios in foraminifera make it possible to reconstruct in detail late neogene vertical motions along the central cretan segment of the hellenic arc these motions are considered to express the surficial effect of the roll back process of the hellenic subduction zone which started about 12 ma ago in contrast to earlier views there is no sustained uplift since the late middle miocene successive paleotopographic profiles for central crete show a predominance of subsidence coupled with an increase of differential reliefs from the latest serravallian until the messinian subsidence was most pronounced between the tortonian messinian boundary interval and the early part of the early pliocene locally up to a magnitude of more than 1000 m a two phased uplift history coupled with tilting to the north or northeast can be inferred from the late early pliocene recent record separated by a short early late pliocene episode of subsidence rates of uplift were highest in the early pliocene up to about 125 cm ka the central cretan late neogene to recent paleotopographic profiles are compared with those reconstructed from seismic interpretations and drilling data from the cretan sea the combined results show that paleotopographic configurations between the cyclades and crete were fairly similar to those on central crete until messinian time foundering of the cretan basin started in the course of the early pliocene but subsidence rates were less than the contemporaneous uplift rates of crete the timing and magnitude of the vertical motions along the cretan sea central cretan transect put detailed geological constraints on tectonophysical modelling of the surficial effects of the roll back process these vertical motions are discussed in view of the model of southward translation of a large supracrustal slab resulting in the origin of the cretan sea and in thrusting and uplift in the frontal parts of the slab where it thrusted over the northern limb of the subducted ionian plate

on the hellenic subduction zone and the geodynamic evolution of crete since the late middle miocene abstract in recent syntheses of the geodynamic evolution of the aegean area the hellenic subduction zone and in particular its initiation plays a central role two basic aspects of the recent comprehensive model put forward by le pichon angelier and co workers are a initiation of subduction along the hellenic arc is inferred to have taken place approximately 13 ma ago whereas several others have suggested approximately 5 ma and b migration of the trench system to the south southwest giving rise to an extensional regime in the back arc region which led to general subsidence and formation of the present day aegean sea new data on the structure of the upper mantle underneath the aegean area indicate that the former aspect requires modification the seismic velocity structure indicating a northward dipping slab down to a depth of at least 600 km and the depth distribution of earthquake hypocenters can not be reconciled with straightforward initiation of subduction approximately 13 ma ago estimates of about 5 ma for the time of initiation of the present subduction zone are even more difficult to reconcile assuming 400 km as an upper bound for the effect of stretching of the aegean sea and of other processes contributing to the separation of crete from the eurasian mainland we arrive at an age for the hellenic subduction zone of at least 26 ma as to aspect b geological data of crete lend strong support to the idea that on crete compressional tectonics is of much greater importance than current models imply combining geophysical and geological data we propose a modification of the tectonic evolution for the cretan segment of the hellenic arc whereas the basic process of extension caused by a migrating trench system roll back in a land locked basin remains a very useful and sound concept the tectonics of the margins of a region subject to stretching in this case crete may be more complicated than hitherto thought in our model the documented fragmentation of crete into several basins which started about 12 ma ago is not attributed to initiation of subduction but to inception of the roll back process compressional tectonics on crete is taken to be associated with deformation of the crust resulting from the overall tensional stress regime

fabric analysis using the intercept method abstract the intercept method is a convenient yet powerful method for the numerical analysis of fabrics for geological applications it can be used when a set of objects e g pores grains or aggregates of a specific mineral lineaments etc with unique characteristics can be identified in an image the intercept method analyses boundaries of objects as a population of lines how intercepts are definined is therefore important in order to establish the significance of the intercept counts when the method is applied to digital images the subdivision of the information into square pixels must also be considered we apply a linear filter which minimizes the effects of grid anisotropy on the counting of intercepts analysis of the resulting rose of intercept counts by a fourier series considerably facilitates the interpretation of the data a rose of directions can readily be derived for the phase boundaries if a population of objects can be assumed to have started with an originally isotropic orientation and to have been deformed passively the fourier components of the rose of intercepts also give the sectional strain the fourier components also permit an objective test of the validity of describing a fabric as resulting from a homogeneous strain on an initially isotropic section two computer programs for the counting and analysis of intercepts on digital images are presented and applied in four examples which illustrate the usefulness of the intercept method for magmatic fabric measurement strain analysis and lineament analysis we also illustrate the importance of fourier series decomposition of rose of intercept counts for fabric interpretations intercept results are also shown to be compatible with those derived by other methods eigenvector surfor inertia tensor autocorrelation methods

characterizing the mesozoic extension direction in the northern iberian plate margin by anisotropy of magnetic susceptibility ams we present the results of anisotropy of magnetic susceptibility ams analyses carried out on weakly deformed triassic red beds jurassic and lower cretaceous limestones sandstones and shales from several northern iberian mesozoic basins located near the northern iberian plate margin santander cabuerniga and polientes basins in the western part of the basque cantabrian basin and bilbao and aralar basins in the central eastern part cameros basin in the northernmost part of the iberian chain a well defined magnetic lineation of tectonic origin is found at most of the sampled sites and is interpreted as the stretching direction resulting from the extensional deformation characterizing this period during the mesozoic the northern margin of the iberian plate underwent two rifting stages the triassic and late jurassic early cretaceous kimmeridgian albian rifting events both the triassic and the period of the late jurassic early cretaceous rifting event with maximum subsidence rates i e until the barremian are characterized by a ne sw extensional direction in the main subsidence areas this indicates that nw se master faults controlled basin subsidence and sedimentation through these periods in the northern iberia plate margin basins conversely during jurassic and aptian times a lower activity of nw se faults together with more important extension along a nw se direction can be inferred from ams analysis this study indicates the power of ams analysis in basin analysis and geodynamic reconstructions even in subsequently inverted basins

geometry kinematics and deformation rates along the active normal fault system in the southern apennines implications for fault growth throw rates throws and kinematic data have been collected from a localised system of active normal faults in the southern apennines italy to assess how its growth history differs from that for a distributed fault system in the central apennines both show evidence for fault interaction in that 1 faults located centrally along strike have higher throws and throw rates than distal faults and 2 cumulative throw and throw rate profiles summed across strike show central maxima with values decreasing to zero at fault system tips however although throw rates increased through time in the central apennines we are unable to resolve such changes if they exist for the southern apennines specifically throw rates derived from offsets of 18 ka geomorphic surfaces are consistent with total throws in the southern apennines when extrapolated back through time but overestimate total throws in the central apennines by a factor of 2 4 suggesting an increase in throw rate through time for the latter we discuss why some fault systems appear to have throw rates that are constant through time whilst others accelerate during growth interaction

slickenside and fault surface kinematic indicators on active normal faults of the alpine betic cordilleras granada southern spain abstract twenty four mesoscopic slickenside kinematic indicators are described here for the pliocene quaternary active normal faults of the alpine betic cordilleras granada southern spain the indicators are classified into twelve groups depending on the down or up slope asymmetric orientation of features such as concavities damaged versus sharp grain borders or step edges v shaped markings fractures and trailed material seventeen of the indicators were not previously described in the literature the new kinematic indicators include two types of asymmetric grains a carrot shaped marking six substructures of congruous and incongruous steps trailed fault material a drop shaped figure a v shaped marking three types of synthetic hybrid fractures with congruous steps and two varieties of pluck holes we think that some of these kinematic indicators provide information on the amount of displacement aseismic versus seismic slip rates cataclastic flow frictional wear or surface polishing

thrust faults and extensional detachment faults in cretan tectono stratigraphy implications for middle miocene extension abstract the revised tectono stratigraphy of crete and especially of the phyllites quartzites complex demonstrated the distinction of the probable paleozoic low medium grade metamorphic rocks of the arna unit from the underlying permo triassic phyllites and associated carbonate sediments trypali facies of western crete unit as well as the overlying permo triassic phyllites and associated sediments of the tyros ravdoucha beds at the base of the tripolis unit the pre existing mixture of the above tectono stratigaphic units in a single complex created a number of misinterpretations as far as stratigraphy metamorphism and interpretation of low angle faults as thrusts or detachments especially in cases where the inferred tectonic contact concerns the transition between the tyros beds and the base of the tripolis carbonate platform there is no structural omission and therefore the contact represents a minor disharmonic sliding surface and not a detachment based on the revised tectono stratigraphic analysis the determination of the structural omission for each tectonic contact was possible and several detachments were described for the first time footwall rocks of the detachments comprised several tectonic units usually from the lower nappes and hanging wall rocks comprised several tectonic units usually from the upper nappes the detachment may separate not only metamorphosed units in the footwall mani western crete arna from non metamorphosed units in the hanging wall tripolis pindos and higher nappes but also all other possible combinations from the cretan nappe pile extension in crete started in the middle late miocene with the formation of extensional detachment faults the reported extensional structures of oligocene to early miocene age do not correspond to crustal extension of crete but to localized shear zones related to nappe stacking and the exhumation of metamorphic rocks extensional detachments in crete form a tectonic horst through two oppositely dipping e w trending zones one dipping north related to the opening of the cretan basin and the other dipping south related to the formation of the messara supra detachment basin the deformation history of units within crete can be summarized as i compressional deformation producing arc parallel east west trending south directed thrust faults in oligocene to early miocene time ii extensional deformation along arc parallel east west trending detachment faults in middle miocene time with hanging wall motion to the north and south and iii late miocene quaternary transtensional deformation along high angle normal and oblique normal faults that disrupt the older arc parallel structures

slickenside kinematic indicators abstract a new classification of slickenside kinematic indicators is presented based on 61 criteria these slickensides have been subdivided into eleven major groups v or crescentic markings steps fractures trains of inclined planar structures trailed material asymmetric elevations deformed elements mineralogical crystallographic orientations asymmetric plan view features asymmetric cavities and asymmetric folds this classification constitutes a useful tool for geologists interested in the determination of the shear sense in fault surfaces bearing slickensides examples of application of this classification to natural fault surfaces at different scales are presented

characterization of the magnetic fabric of rocks abstract an inextensive system of magnetic susceptibility anisotropy factors is suggested which is sufficient in the majority of practical applications for characterizing the magnetic fabric of rocks the system involves three newly devised factors the corrected anisotropy degree the shape factor and the difference shape factor the first of these characterizes the quantity of anisotropy somewhat better than the commonly used anisotropy degree the shape factor characterizes the quality of anisotropy i e the shape of the susceptibility ellipsoid in a convenient way its definition is based on a certain analogy between the anisotropy ellipsoid and the strain ellipsoid the difference shape factor can replace the shape factor when only the differences between the principal susceptibilities are given while the mean susceptibility is unknown

phyllosilicate fabric characterization by low temperature anisotropy of magnetic susceptibility lt ams 1 this paper examines the use and applicability of anisotropy of magnetic susceptibility at low temperature 77 k called lt ams paramagnetic susceptibility increases significantly with low temperature which permits high precision determination of the anisotropy of paramagnetic susceptibility of a rock from measurements at liquid nitrogen temperature we describe a new procedure that measures directional susceptibility in an oriented rock specimen while immersed in liquid nitrogen our procedure overcomes the problem of temperature heterogeneity within a rock sample while its susceptibility is being measured offering the opportunity to measure low temperature susceptibility in multiple orientations this non destructive method provides a way of characterizing the principal paramagnetic minerals present in a rock based on temperature induced changes of the anisotropy degree moreover the method offers a better resolved relationship between anisotropy degree and grain alignment which is used to quantify rock fabrics

multidisciplinary approach to constrain kinematics of fault zones at shallow depths a case study from the cameros demanda thrust north spain thrusting at shallow depths often precludes analysis by means of structural indicators effective in other geological contexts e g mylonites sheath folds shear bands in this paper a combination of techniques including structural analysis magnetic methods as anisotropy of magnetic susceptibility and paleomagnetism and paleothermometry is used to define thrusting conditions deformation and transport directions in the cameros demanda thrust north spain three outcrops were analyzed along this intraplate large scale major structure having 150 km of outcropping length 30 km of maximum horizontal displacement and 5 km of vertical throw results obtained by means of the different techniques are compared with data derived from cross sections and stratigraphic analysis mixed layer illite smectite and vitrinite reflectance indicating deep diagenetic conditions and mature stage of hydrocarbon generation suggests shallow depths during deformation thus confirming that the protolith for most of the fault rocks is the footwall of the main thrust kinematic indicators foliation s c structures and slickenside striations indicate altogether a dominant nnw movement of the hanging wall in the western zone and ne in the eastern zone of the thrust thus implying strain partitioning between different branches of the main thrust the study of ams in fault rocks nearly 400 samples of fault gouge breccia and microbreccia indicates that the strike of magnetic foliation is oblique to the transport direction and that the magnetic lineation parallelizes the projection of the transport direction onto the k max k int plane in sites with strong shear deformation paleomagnetism applied to fault rocks indicates the existence of remagnetizations linked to thrusting in spite of the shallow depth for deformation and a strong deformation or scattering of the magnetic remanence vectors in the fault zone the application of the described techniques and consistency of results indicate that the proposed multidisciplinary approach is useful when dealing with thrusts at shallow crustal levels

tsunami deposits on the coastline of west crete greece abstract the eastern mediterranean and the aegean sea in particular are the most active seismic regions in europe historically numerous earthquakes have occurred in this part of the world and comprehensive tsunami recordings exist nevertheless field evidence of tsunamis is rare although many neotectonic movements certainly must have triggered very strong tsunami waves along the coastlines of western crete we found evidence for tsunami impacts such as 1 bimodal deposits large clasts floating in sands comprised of shell fragments 2 dislocation of large boulders with tilting of biogenous notches and 3 boulders with lithophaga or cliona borings weighing up to 75 tons thrown onshore and imbedded in strata of marine shells this paper documents these deposits and discusses whether they originated from the sudden uplift that occurred in 365 ad moreover numerical radiocarbon ages reveal the occurrence of two tsunamis dated to 5660 yrs bp and 500 yrs bp evidence for other tsunami impacts is discussed but not supported by numerical dating due to the lack of suitable material

extensional subsidence contractional folding and thrust inversion of the eastern cameros basin northern spain tectonic analysis of the cameros massif northern spain demonstrates the need to integrate detailed structural analysis with stratigraphic studies in order to understand the development of inverted basins the cameros massif underwent three major tectonic events each characterized by different mechanisms of deformation the first event tithonian early albian manifested as continental rifting and formation of the cameros basin and was attended by normal faulting and related folding of pre and syn rift sedimentary sequences up to 9 km thick it corresponded to the beginning of rifting and opening of the bay of biscay to the north of the massif the second event occurred at the end of the early cretaceous the basin underwent contraction manifested as gentle folds containing axial plane cleavage this contraction was due to the migration of the center of rifting away from the basin and toward the northeast and correlates with the onset of oceanic spreading in the bay of biscay deformation happened during a low grade metamorphism period that reached its thermal peak after folding and cleavage formation 90 100 ma the final stage of deformation eocene miocene following a structurally quiescent period of approximately 40 ma occurred during the convergence collision between iberia and europe it formed contractional folds related to large e w striking overthrusts the mesozoic basin was inverted and transported 25 km toward the north during this stage both unfolding and tightening of the former folds occurred as determined from analysis of cleavage orientation associated with the previous shortening

paleostress states at the south western margin of the central european basin system application of fault slip analysis to unravel a polyphase deformation pattern abstract we analyse the deformation pattern along the south western margin of the central european basin system cebs where upper carboniferous mesozoic rocks are uplifted due to the late cretaceous basin inversion the geometry of mesoscale faults and associated striae are used to calculate the stress state s responsible for the observed deformation each reduced stress tensor obtained comprises i the directions of the principal stress axes 1 2 and 3 1 2 3 and ii the ratio of principal stress differences r 2 3 1 3 we present a stress inversion technique that allows each stress state inherent in a heterogeneous fault population to be identified by integrating the results of the pbt method turner f j 1953 nature and dynamic interpretation of deformation lamellae in calcite of three marbles american journal of sciences 251 4 276 298 sperner b ratschbacher l and ott r 1993 fault striae analysis a turbo pascal program package for graphical presentation and reduced stress tensor calculation computers geosciences 19 1361 1388 and the multiple inverse method yamaji a 2000 the multiple inverse method a new technique to separate stresses from heterogeneous fault slip data journal of structural geology 22 4 441 452 this comprehensive approach not only facilitates the separation of complex data sets into homogeneous subsets but also guarantees that each stress state derived fulfils both the criteria of low misfit angles wallace bott hypothesis and high shear to normal stress ratios mohr coulomb criterion the reliability of our technique is confirmed by the fact that irrespective of i the number of fault slip data from an outcrop ii the number of subsets they represent and iii the proportion of newly formed and reactivated faults we obtain consistent results from outcrops of variously aged rocks this consistency concerns both calculated stress states as well as locally observed deformation sequences such local chronologies are derived from cross cutting relationships and superimposition of different fault slip data which individually are assigned to a consistent stress state a synthesis of results from different locations of the study area argues for the superposition of two main deformation events most prominently the area was affected by a stress state with a horizontal n s to ne sw directed maximum compression 1 and a low stress ratio which induced reverse and strike slip faulting a pure strike slip regime of e w to nw se directed compression with moderate stress ratios is less prevalent and probably younger the age of the youngest rocks documenting these two phases proves the stress fields to correspond to the polyphase late cretaceous tertiary basin inversion of the cebs during post cenomanian times the youngest tectonic imprints detected in the study area correspond to locally appearing extensional stress states with varying directions of 3 at many sites the youngest derived paleostress state coincides with the present day stress field in terms of the direction of the maximum horizontal stress axis s hmax the only stress state detected which pre dates the basin inversion corresponds to an extensional regime with an wnw ese to nw se directed 3 axis observed only locally in the n s striking leine graben and its prolongation to the north the fact that the majority of variously aged rocks exhibit only the traces of the latest deformation phases indicates a high degree of fault plane reactivation in the study area

a reconciled estimate of ice sheet mass balance we combined an ensemble of satellite altimetry interferometry and gravimetry data sets using common geographical regions time intervals and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of earth s polar ice sheets we find that there is good agreement between different satellite methods especially in greenland and west antarctica and that combining satellite data sets leads to greater certainty between 1992 and 2011 the ice sheets of greenland east antarctica west antarctica and the antarctic peninsula changed in mass by 142 49 14 43 65 26 and 20 14 gigatonnes year 1 respectively since 1992 the polar ice sheets have contributed on average 0 59 0 20 millimeter year 1 to the rate of global sea level rise

slip vector analysis with high resolution t lidar scanning abstract a palaeostress analysis of an active bedrock normal fault scarp based on kinematic indicators is reconstructed using terrestrial laser scanning tls for this purpose three key elements are necessary for a defined region i the orientation of the fault plane ii the orientation of the slickenside lineation or other kinematic indicators and iii the sense of motion of the hanging wall the paper specifies a workflow in order to obtain stress data from point cloud data using terrestrial laser scanning tls in an active tectonic environment the entire analysis was performed on a continuous limestone bedrock normal fault scarp on the island of crete greece at four different locations along the wnw ese striking spili fault at each location we collected data with the terrestrial light detection and ranging system t lidar we then validated the calculated three dimensional stress results at three of the locations by comparison with conventional methods using data obtained manually with a compass clinometer numerous kinematic indicators for normal faulting were discovered on the fault plane surface using t lidar data when comparing all reconstructed stress data obtained from t lidar to that obtained through manual compass measurements the degree of fault plane orientation divergence is 005 03 for dip direction and dip the degree of slickenside lineation divergence is 003 03 for dip direction and dip therefore the percentage threshold error of the individual vector angle at each investigation site is lower than 3 for the dip direction and dip for planes and lower than 6 for the strike the maximum mean variation of the complete calculated stress tensors is 005 03

antarctica greenland and gulf of alaska land ice evolution from an iterated grace global mascon solution we have determined the ice mass evolution of the antarctica and greenland ice sheets ais and gis and gulf of alaska goa glaciers from a new grace global solution of equal area surface mass concentration parcels mascons in equivalent height of water the mascons were estimated directly from the reduction of the inter satellite k band range rate kbrr observations taking into account the full noise covariance and formally iterating the solution the new solution increases signal recovery while reducing the grace kbrr observation residuals the mascons were estimated with 10 day and 1 arc degree equal area sampling applying anisotropic constraints an ensemble empirical mode decomposition adaptive filter was applied to the mascon time series to compute annual mass balances the details and causes of the spatial and temporal variability of the land ice regions studied are discussed the estimated mass trend over the total gis ais and goa glaciers for the time period 1 december 2003 to 1 december 2010 is 380 plus or minus 31 gt a exp 1 equivalent to 1 05 plus or minus 0 09 mma exp 1 sea level rise over the same time period we estimate the mass acceleration to be 41 plus or minus 27 gt a exp 2 equivalent to a 0 11 plus or minus 0 08 mm a exp 2 rate of change in sea level the trends and accelerations are dependent on significant seasonal and annual balance anomalies

tertiary compressional overprint on aptian albian extensional magnetic fabrics north pyrenean zone abstract the mauleon basin constitutes part of the north pyrenean mesozoic extensional basins inverted during pyrenean late cretaceous tertiary orogeny a structural and magnetic fabric study of the aptian albian black marls of the mauleon basin north pyrenean zone provides new data indicating that when there is an intense deformation associated with the compressional stage formation of a pervasive foliation the magnetic lineation is strongly controlled by the latter tectonic deformation recorded in the basin however some areas of the sedimentary basin can still preserve the primary extensional event depending on its position with respect to basin margin faults and heterogeneous deformation areas structural and ams data define a fabric transition from extensional fabrics indicating an approximate n s extension in the central inner domain of the basin where compressional deformation was moderate to ne sw compressional fabrics in boundary domains close to the inverted faults where compressional deformation was more important k max becomes nearly parallel to the main pyrenean direction nw se consequently fabrics in the mauleon basin can be interpreted as the result of the overprint of compressional deformation onto a primary extensional fabric which in turn endures in the central domain of the basin in spite of its complicated pattern ams is revealed useful when considering the long term history of sedimentary basins undergoing several deformation events

postnappe stacking extension and exhumation of high pressure low temperature rocks in the island of crete greece the island of crete consists largely of nappes of contrasting lithologies and metamorphism that were stacked southward during an oligocene early miocene n s compression with the lower nappes undergoing a high pressure low temperature hp lt metamorphism this was followed by a n s miocene crustal extension that caused thinning of the nappes and uplift of the hp lt metamorphic rocks ductile conditions took place in the lower nappes associated with a retrograde greenschist metamorphism while semiductile to brittle conditions took place in the upper nappes a major normal detachment fault separates the lower and the upper nappes the quartz texture analyses and the symmetry of structures indicate bulk coaxial deformation while the results of strain analysis suggest both constrictional and flattening strains a younger ne sw compression affected both the thinned nappe pile and the late miocene pliocene sedimentary basins finally a pliocene ne sw extension led to further uplift and exhumation of the hp lt metamorphic rocks this cyclic tectonometamorphic process of alternate compression and extension took place during the migration of the hellenic orogenic belt toward the most external units including successive tectonic events

slip distributions on active normal faults measured from lidar and field mapping of geomorphic offsets an example from l aquila italy and implications for modelling seismic moment release surface slip distributions for an active normal fault in central italy have been measured using terrestrial laser scanning tls in order to assess the impact of changes in fault orientation and kinematics when modelling subsurface slip distributions that control seismic moment release the southeastern segment of the surface trace of the campo felice active normal fault near the city of l aquila was mapped and surveyed using techniques from structural geology and using tls to define the vertical and horizontal offsets of geomorphic slopes since the last glacial maximum 15 3 ka the fault geometry and kinematics measured from 43 sites and throw heave measurements from geomorphic offsets seen on 250 scarp profiles were analysed using a modification of the kostrov equations to calculate the magnitudes and directions of horizontal principal strain rates the map trace of the studied fault is linear except where a prominent bend has formed to link across a former left stepping relay zone the dip of the fault and slip direction are constant across the bend throw rates since 15 3 ka decrease linearly from the fault centre to the tip except in the location of the prominent bend where higher throw rates are recorded vertical coseismic offsets for two palaeo earthquake ruptures seen as fresh strips of rock at the base of the bedrock scarp also increase within the prominent bend the principal strain rate calculated by combining strike dip slip direction and post 15 3 ka throw rate decreases linearly from the fault centre towards the tip the strain rate does not increase across the prominent fault bend the above shows that changes in fault strike whilst having no effect on the principal horizontal strain rate can produce local maxima in throw rates during single earthquakes that persist over the timescale of multiple earthquakes 15 3 ka detailed geomorphological and structural characterisation of active faults is therefore a critical requirement in order to properly define fault activity for the purpose of accurate seismic hazard assessment we discuss the implications of modelling subsurface slip distributions for earthquake ruptures through inversion of gps insar and strong motion data using planar fault approximations referring to recent examples on the nearby paganica fault that ruptured in the mw 6 3 2009 l aquila earthquake

ice flow of the antarctic ice sheet we present a reference comprehensive high resolution digital mosaic of ice motion in antarctica assembled from multiple satellite interferometric synthetic aperture radar data acquired during the international polar year 2007 to 2009 the data reveal widespread patterned enhanced flow with tributary glaciers reaching hundreds to thousands of kilometers inland over the entire continent this view of ice sheet motion emphasizes the importance of basal slip dominated tributary flow over deformation dominated ice sheet flow redefines our understanding of ice sheet dynamics and has far reaching implications for the reconstruction and prediction of ice sheet evolution

estimation of icesat intercampaign elevation biases from comparison of lidar data in east antarctica 1 the ice cloud and land elevation satellite icesat laser campaign elevation biases are estimated from an analysis of icesat and airborne land vegetation and ice sensor lidar intrasensor and intersensor elevation differences from two regions of the antarctic ice sheet that experienced minimal surface elevation change elevation observations are corrected for a combination of accumulation melting and firn densification processes and glacial isostatic adjustment icesat elevations are adjusted for the saturation and gaussian centroid corrections relative to laser campaign l3i biases are found to be less than 8 cm except for campaign l2e at 14 72 cm corresponding to the time of a significant accumulation anomaly in east antarctica the intercampaign bias trend estimated from intersensor elevation differences computed over campaigns l2a to l2f september 2003 to october 2009 excluding l2e is 1 04 0 48 cm yr the intercampaign bias trend represents a correction to icesat derived antarctica mass balance of 117 53 gt yr

review of earth science research using terrestrial laser scanning abstract the application of advanced remote sensing technologies including terrestrial laser scanning tls to the earth sciences has increased rapidly in the last two decades improving the spatial and temporal resolution of data terrestrial laser scanning units have evolved into a common tool in studies of spectral and structural geology seismology natural hazards geomorphology and glaciology special consideration of the advantages and limitations of tls in each of these fields is discussed in depth in the context of important work published in each field the workflow used in a tls survey is crucial to the success of the survey and field specific earth science workflows are therefore also discussed products based on tls data such as triangulated irregular networks tin and digital surface models dsm are commonplace tools throughout the earth sciences and the use of these tools to measure slip distributions fault geometries aeolian transport river bed morphologies and flows and other research problems is expanded on where appropriate the review concludes with a discussion of recent trends in tls instrument development and their potential impact on the use of tls in the earth sciences in the future

greenland ice sheet mass balance distribution of increased mass loss with climate warming 2003 07 versus 1992 2002 we derive mass changes of the greenland ice sheet gis for 2003 07 from icesat laser altimetry and compare them with results for 1992 2002 from ers radar and airborne laser altimetry the gis continued to grow inland and thin at the margins during 2003 07 but surface melting and accelerated flow significantly increased the marginal thinning compared with the 1990s the net balance changed from a small loss of 7 3g t a 1 in the 1990s to 171 4g t a 1 for 2003 07 contributing 0 5 mm a 1 to recent global sea level rise we divide the derived mass changes into two components 1 from changes in melting and ice dynamics and 2 from changes in precipitation and accumulation rate we use our firn compaction model to calculate the elevation changes driven by changes in both temperature and accumulation rate and to calculate the appropriate density to convert the accumulation driven changes to mass changes increased losses from melting and ice dynamics 17 206 gt a 1 are over seven times larger than increased gains from precipitation 10 35 gt a 1 during a warming period of 2 k 10 a 1 over the gis above 2000 m elevation the rate of gain decreased from 44 to 28 gt a 1 while below 2000 m the rate of loss increased from 51 to 198 gt a 1 enhanced thinning below the equilibrium line on outlet glaciers indicates that increased melting has a significant impact on outlet glaciers as well as accelerating ice flow increased thinning at higher elevations appears to be induced by dynamic coupling to thinning at the margins on decadal timescales

assessing the performance of 20 25 m footprint waveform lidar data collected in icesat data corridors in greenland 1 the precision and accuracy of surface elevation measurements of the greenland ice sheet provided by 20 25 m footprint waveform laser altimetry is assessed using data collected by nasa s lvis airborne lidar in september 2007 repeated data acquisitions from two 850 km long transects over the ice sheet and a 30 km long transect in the summit area are evaluated for consistency and compared to in situ data for validation comparisons to data collected by nasa s icesat system reveal good agreement in the summit area differences are better than 0 07 m 1 except for l3c where it is 0 13 m with mean offsets of 0 09 to 0 16 m depending on the campaign within the feeder zone to jakobshavn glacier ice elevation decreases of up to 12 m 2004 2008 are observed the results suggest that 25 m waveform lidar can measure ice sheet elevation precisely and accurately and that the measurement scheme could be used to complement the legacy icesat measurements

height changes over subglacial lake vostok east antarctica insights from gnss observations height changes of the ice surface above subglacial lake vostok east antarctica reflect the integral effect of different processes within the subglacial environment and the ice sheet repeated gnss global navigation satellite systems observations on 56 surface markers in the lake vostok region spanning 11 years and continuous gnss observations at vostok station over 5 years are used to determine the vertical firn particle movement vertical marker velocities are derived with an accuracy of 1 cm yr or better repeated measurements of surface height profiles around vostok station using kinematic gnss observations on a snowmobile allow the quantification of surface height changes at 308 crossover points the height change rate was determined at 1 5 mm yr thus indicating a stable ice surface height over the last decade it is concluded that both the local mass balance of the ice and the lake level of the entire lake have been stable throughout the observation period the continuous gnss observations demonstrate that the particle heights vary linearly with time nonlinear height changes do not exceed 1 cm at vostok station and constrain the magnitude of spatiotemporal lake level variations icesat laser altimetry data confirm that the amplitude of the surface deformations over the lake is restricted to a few centimeters assuming the ice sheet to be in steady state over the entire lake estimates for the surface accumulation on basal accretion melt rates and on flux divergence are derived

high resolution ground based gps measurements show intercampaign bias in icesat elevation data near summit greenland the geoscience laser altimeter system glas aboard the national aeronautics and space administration s ice cloud and land elevation satellite icesat collected data from early 2003 to late 2009 with the specific goal of measuring ice surface elevation changes while the precision of glas instrumentation has been studied over its intended target ice its accuracy has only been robustly estimated using independent terrestrial nonlaser methods over salt flats here we perform repeat high precision global positioning system gps surveys under four passes of icesat track 0412 campaigns l3i l3j l2d and l2e to compare directly glas elevation data footprints to a coincident gps ground truth near summit greenland analysis and comparison of glas data with gps data show a campaign dependent elevation bias ranging from 0 112 0 030 m l3j to 0 121 0 071 m l2e although uncorrected reflectance values and field observations both indicate that forward scattering of the laser signal through the atmosphere accounts for the anomalously negative l3j bias the biases of all campaigns studied are within the instrument s goal accuracy of 0 15 m however our analysis shows a campaign dependence in the bias which may propagate through estimates of mass balance the error introduced from intercampaign biases illustrates the importance of long term independent validation experiments of satellite altimetry data over ice sheets

two and three dimensional shape fabric analysis by the intercept method in grey levels the count intercept is a robust method for the numerical analysis of fabrics launeau and robin 1996 it counts the number of intersections between a set of parallel scan lines and a mineral phase which must be identified on a digital image however the method is only sensitive to boundaries and therefore supposes the user has some knowledge about their significance the aim of this paper is to show that a proper grey level detection of boundaries along scan lines is sufficient to calculate the two dimensional anisotropy of grain or crystal distributions without any particular image processing populations of grains and crystals usually display elliptical anisotropies in rocks when confirmed by the intercept analysis a combination of a minimum of 3 mean length intercept roses taken on 3 more or less perpendicular sections allows the calculation of 3 dimensional ellipsoids and the determination of their standard deviation with direction and intensity in 3 dimensions as well the feasibility of this quick method is attested by numerous examples on theoretical objects deformed by active and passive deformation on bse images of synthetic magma flow on drawing or direct analysis of thin section pictures of sandstones and on digital images of granites directly taken and measured in the field

scales of structural heterogeneity within neotectonic normal fault zones in the aegean region abstract structural heterogeneities within neotectonic normal fault zones in the aegean region are important controls on the geomorphic expression of their uplifted footwall blocks contrasting fault rocks and slip plane phenomena corrugations comb fractures slip parallel fractures and pluck holes are responsible for mesoscopic inhomogeneities within fault scarps along strike disruptions in the continuity of fault scarps step over zones step up zones step down zones footwall cross faults and hangingwall cross faults are products of perturbations in slip plane geometry or intersections with transverse faults large scale variations in range front morphology reflect contrasting patterns of deformation within fault zones some major fault zones and many minor fault zones are characterized by a migration of the active slip plane towards the hangingwall resulting in a distributed network of high angle faults and a range front which is stepped in profile the presence of a localized mass of uneroded bedrock hangingwall salients protruding from the hangingwall of some major fault zones results in intense deformation along a principal slip plane and a range front which is ramp like in profile as a consequence of structural heterogeneities within neotectonic normal fault zones fault scarps and range fronts in the aegean region are subject to a temporally and spatially variable pattern of degradation

reprint of bedrock fault scarp history insight from t lidar backscatter behaviour and analysis of structure changes abstract this paper provides a research approach and develops a methodology that helps natural weathered bedrock fault scarps to be understood in terms of their structural changes and backscatter behaviour when using terrestrial laser scanning t lidar we tested our approach on the pisia fault in greece that ruptured during the 1981 alkyonides earthquake sequence in corinth gulf the method describes how to correlate fault geometry and structural variations with the backscatter signal of t lidar data from naturally exhumed bedrock fault scarps using this method we are able to reconstruct the past slip history we used t lidar for the analysis of the monochromatic laser beam s backscattered signal to define unsupervised classes of unknown objects on fault surface seven classes were created based on the dendrogram technique using the maximum likelihood method these were used to determine their spatial distribution throughout the scarp height and to calculate the terrain ruggedness index tri in the defined classes the combination of these results shows that i the ruggedness increases with the scarp height and ii the ruggedness and backscattering describe different fault plane conditions we found evidence for past earthquakes on the pisia fault at our study site with average displacements in the range of 30 60 cm with corresponding magnitudes of 6 4 6 6 0 1 ms these results help to reconstruct the recent fault history and potential palaeo events and can also be used i to detect appropriate sample sites on the fault plane for absolute dating and ii as an independent constraint on tracing slip events assisting absolute dating techniques this method can significantly reduce the sampling requirements and costs of cosmogenic absolute dating techniques overall it might be a valuable tool for extracting data regarding the faulting history and slip events for defining seismic hazard parameters

coseismic and postseismic subsurface displacements and strains for a dip slip normal fault in a three layer elastic gravitational medium a three layer elastic gravitational fault displacement model has been developed using elastic dislocation and employed to examine the effects of rigidity layering gravity and stress relaxation on surface and subsurface displacements fields for a dip slip normal fault within our three layer model layer 1 represents the upper crust layer 2 the lower crust and layer 3 the upper mantle the fault is embedded in the upper crust horizontal as well as vertical displacement components have been determined displacement field changes due to postseismic stress relaxation have been calculated using both the correspondence principle and relaxed rigidity moduli and results are in close agreement the relaxed rigidity method provides an accurate and computationally efficient method of examining postseismic relaxation postseismic relaxation within the lower two layers only gives surface uplift increasing footwall uplift and decreasing hangingwall subsidence and also increases the wavelength of surface vertical displacement postseismic stress relaxation within all three layers i e uniform half space produces a shorter wavelength of surface vertical deformation with respect to the coseismic response moho topography created during coseismic deformation is initially amplified during postseismic relaxation the relaxed moho topography is dependent on the strength of the upper crust as well as the strength of the lower crust and mantle gravity has a significant influence on displacements only at the postseismic stage when the effective rigidity of the lower layers is small coseismic and postseismic normal strains associated with dip slip normal faulting have been examined for a large normal basement fault intersecting the free surface the coseismic horizontal surface strain perpendicular to fault strike is compressive adjacent to the fault and in the footwall and tensile in the hangingwall away from the fault coseismic stress redistribution may generate significant tensile brittle failure of the upper crust adjacent to large basement faults

strain indicators and magnetic fabric in intraplate fault zones case study of daroca thrust iberian chain spain abstract anisotropy of magnetic susceptibility ams has been applied to the study of shallow fault zones although interpretation of the results requires establishing clear relationships between petrofabric and magnetic features magnetic behaviour of fault rocks and an extensive knowledge of p t conditions in this work we demonstrate that magnetic methods can be applied to the study of heterogeneous fault zones provided that a series of requisites are met a major fault zone within the iberian plate daroca thrust showing transpressional movements during cenozoic time was chosen for this purpose because of the exceptional outcrops of fault gouge and microbreccia and its relevance within the context of the northeastern iberian plate magnetic fabrics were analysed and the results were compared with foliation and s c structures measured within the fault zone clay mineral assemblages suggest maximum burial depths shallower than 2 km

characterization of fault roughness at various scales implications of three dimensional high resolution topography measurements accurate description of the topography of active fault surfaces represents an important geophysical issue because this topography is strongly related to the stress distribution along fault planes and therefore to processes implicated in earthquake nucleation propagation and arrest to date due to technical limitations studies of natural fault roughness either performed using laboratory of field profilometers were obtained mainly from 1 d profiles with the recent development of light detection and ranging lidar apparatus it is now possible to measure accurately the 3 d topography of rough surfaces with a comparable resolution in all directions both at field and laboratory scales in the present study we have investigated the scaling properties including possible anisotropy properties of several outcrops of two natural fault surfaces vuache strike slip fault france and magnola normal fault italy in limestones at the field scale digital elevation models of the fault roughness were obtained over surfaces of 0 25 m2 to 600 m2 with a height resolution ranging from 0 5 mm to 20 mm at the laboratory scale the 3 d geometry was measured on two slip planes using a laser profilometer with a spatial resolution of 20 m and a height resolution less than 1 m

non planarity scale dependent roughness and kinematic properties of the pidima active normal fault scarp messinia greece using high resolution terrestrial lidar data abstract terrestrial lidar tls photogrammetric and field data were collected during the years 2014 2015 and 2017 at a 20 m long limestone scarp locality along the n s striking 70 west dipping active pidima fault messinia sw peloponnese greece this locality presents an artificially exhumed portion of an active fault plane thus providing a unique opportunity to study kinematics and limestone scarp morphology including its curvature and roughness the survey of 2015 offered a high density point cloud of the fault scarp with 6 mm working resolution creating a very close to real life representation 3d model we found that scarp geometry is non planar with increasing convexity up dip and increasing northwesterly dip directions from north towards south along strike non planarity is also recorded from the morphological data along strike with the appearance of several slip parallel troughs and ridges with a mean distance half wavelength of 0 75 m the fault plane roughness absolute values is scale dependent the roughness configuration attains a slip parallel pattern for observation scales above 1 cm at observations scales less than 1 cm a slip normal pattern is weakly visible the obtained tls results agree with field data manual compass measurements and macroscopic observations we infer an earthquake magnitude of 6 2 0 2 for the last event along the pidima fault based on the measured thickness of the smooth stripe that was imaged by t lidar along the non exhumed surface of the scarp

kinematic indicators on active normal faults in western turkey quaternary normal fault zones in western turkey comprise multiple slip planes and zone parallel layers of fault breccia they also contain several little known kinematic indicators that are probably typical of many formed at shallow levels in extending terrains the recent exhumation by contractors of about 2000 m2 of slip planes in a sse dipping fault zone separating quaternary colluvium from bedrock carbonates at yavansu 7 km se of kusadasi permits an unusually complete inventory of the indicators to be compiled the most spectacular indicators are metre scale 69 w pitching corrugations in slip planes and recemented breccia sheets underlying them corrugations characterized by sinusoidal profiles normal to their long axes and less commonly culminations and depression along their axes possibly developed as a result of upwards propagating slip planes seeking undemanding pathways through heterogeneous fault precursor breccias that formed in advance of tip lines parallel to corrugation long axes are those of gutters flat floored sleep sided channels a few centimetres wide probably related to the abrasion of subslip plane breccia sheets centimetre scale tool tracks scored in the uppermost subslip plane breccia sheet by resistant colluvial clasts are irregular at their proximal ends but distally they swing into alignment with corrugation axes frictional wear striae centimetres long but only a few millimetres wide and pitching 78 w are superimposed on the other slip parallel lineations comb fractures nearly perpendicular to slip planes define an intersection lineation which is normal to corrugation axes fault plane solutions of earthquakes on sse dipping active faults in the west anatolian extensional province indicate that mainly normal combined with minor dextral slip is the dominant mode a conclusion in accord with the sense of slip inferred from the indicators exposed on the yavansu slip planes

magnetic anisotropy rock fabrics and finite strain in deformed sediments of sw sardinia italy abstract although some empirical relationships have been established between the anisotropy of magnetic susceptibility ams and the state of finite strain in studies from specific geologic areas the mechanisms governing correlations are not well understood a comparative study has been made in order to elucidate the ams strain relationship by investigating mineral preferred orientations and the responsible microstructural deformation processes detailed analyses are presented from low grade metamorphic slates of a palaeozoic sequence exposed in the variscan of sw sardinia rock magnetic experiments suggest that paramagnetic minerals dominate the ams in these rocks excellent agreement was found between magnetic fabrics and lattice preferred orientations 001 of mica and chlorite determined from x ray texture goniometry measurements depending on the oblate or prolate ellipsoidal shape of anisotropy the minimum principal axes of ams and x ray textures can coincide with the poles to slaty cleavage or the maximum principal axes can coincide with the bedding cleavage intersection respectively the measured ams and x ray textures only partially reflect the finite strain determined from deformed micro pebbles and reduction spots axial orientations of magnetic fabrics mica and chlorite preferred orientations and finite strain ellipsoids are generally in good agreement depending on development of oblate or prolate fabric ellipsoidal shapes linear correlations can be established for magnitudes of minimum and intermediate axes of the ams and finite strain ellipsoids but shape comparisons are complex microstructural studies by scanning electron microscopy sem indicate that the preferred orientation of the phyllosilicates is caused by different grain scale deformation mechanisms such as kinking micro folding and preferential growth thus magnetic fabrics and mineral preferred orientations evidently result from different deformation mechanisms than the finite strain they reflect the heterogeneous deformation due to micro mechanical reorientation processes of mineral grains while finite strain reflects the homogeneous deformation accommodated cumulatively by the strain markers

faulting and effects of earthquakes on minoan archaeological sites in crete greece abstract examination of damages affecting the buildings of the archaeological sites of phaistos and agia triada southern crete suggests that these minoan settlements were probably destroyed by two major seismic events characterized by mks intensities of ix x and occurred at the end of the protopalatial 1700 bc and the neopalatial 1450 bc periods geological and morphological studies carried out in the neighbouring areas show the occurrence of e w trending quaternary normal fault segments spili and agia galini faults that control the present topography and morphology and exhibit steep young scarps mostly holocene in age these fault segments are related to a nw se extension direction which is consistent with that indicated by the available focal mechanisms of the earthquakes occurring in this area in the last 50 years combining structural and seismic data we can infer that the spili and agia galini fault segments could represent good candidates to be considered active faults generating large earthquakes m 6 5 that were responsible for the damages of phaistos and agia triada this hypothesis suggests that the minoan palatial centres were destroyed by several large earthquakes related to ruptures along distinct fault segments rather than by a single catastrophic event that caused the abrupt destruction of the minoan civilisation in the eastern mediterranean

along strike variations of the slip direction on normal faults insights from three dimensional finite element models normal faults in nature exhibit a systematic variation of the slip direction along strike with pure dip slip at their centres that changes gradually to oblique slip near their tips here we evaluate the variation of the slip direction along normal faults by three dimensional finite element modelling the model results reveal a nearly linear increase of the strike slip component over two thirds of the distance from the fault centre to its tips which results in an increasing obliqueness of the slip vector along strike excluding the fault tips the relationship between lateral slip and fault length can be approximated by a power law function which shows that the strike slip component is proportional to the dip slip and to the fault dip the development of the sinistral and dextral slip components is caused by the orientation of the minimum principal stress which is deflected toward the fault centre in both footwall and hanging wall a comparison with two faults in the central apennines italy shows good agreement between modelled and measured slip vectors the occurrence of converging slip patterns implies that caution is advised when inferring oblique extension regional stress trajectories and palaeostress fields from slip vectors measured away from the fault centre

stress deflection in a tectonic compressional field a model for the northwestern iberian chain spain by means of fault population analysis using the right dihedra y r diagram and etchecopar s methods the states of stress in a number of sites of the cameras massif northwestern iberian chain spain and nearby areas of the ebro basin have been determined these states of stress have been used as a framework in order to infer a model of the actual stress field in that area during the main stage of the alpine compression oligocene lower miocene the three main compression directions obtained nw se nne ne sw can be explained by a single compression field with horizontal 1 trending nne and vertical 2 whose primary trajectories are deflected due to 1 large scale strike slip faults or lateral ramps of thrusts or 2 frontal ramps of thrusts oblique to the main compressive axis the reliability of this scheme has been checked by means of a two dimensional mathematical model based upon the finite element method and applied on a sheet whose rheological properties are similar to those of a standard limestone this model simulates the main features of the regional stress field and it was constructed after determining the average parameters of the possible external or primary field and simulating the major faults that could deflect the stress trajectories

quantification of fabrics in clay gouge from the carboneras fault spain and implications for fault behavior abstract clays in fault rocks have the potential to control fault behavior the formation of frictionally weak clays in fault rocks can lead to fault zone weakening and the development of fabrics through authigenesis and mechanical rotation in clay rich fault rocks can influence fault zone permeability structures the left lateral carboneras fault of southwestern spain is a ca 1 km wide fault zone with anastomosing layers of clay rich gouge up to 50 m thick the gouge derived largely from mica schist is composed of neoformed illite and chlorite anisotropy of magnetic susceptibility 201 measurements and x ray pole figures 144 measurements show comparable oblate clay fabrics with the axis of maximum anisotropy sub parallel to strike this dimensional fabric contrasts with previously published maximum permeability results that are sub vertical this observation coupled with the generally poor clay fabric measured in the samples indicates that the orientation of clays is not likely to be the primary control of the permeability anisotropy of clay rich fault gouge becoming important only when gouge zones are 10s of meters thick which is very unusual even in a fault zone like that of the carboneras fault with thick very clay rich gouge zones with a visible foliations and slip surfaces the degree of clay preferred orientation is low above the millimeter scale showing that any strong clay fabric associated with the foliation are extremely localized phenomena this suggests that processes operating below the millimeter scale may significantly influence fault behavior a result compatible with earlier characterizations of faults in a variety of geologic settings highlighting the importance of understanding how the formation and fabric of fault related authigenic clays influence fault behavior

active faulting on the island of crete greece in order to characterize and quantify the middle late quaternary and ongoing deformation within the southern aegean forearc we analyse the major tectonic structures affecting the island of crete and its offshore the normal faults typically consist of 4 30 km long dipslip segments locally organised in more complex fault zones they separate carbonate and or metamorphic massifs in the footwall block from loose to poorly consolidated alluvial and colluvial materials within the hangingwall all these faults show clear evidences of recent re activations and trend parallel to two principal directions wnw ese and nne ssw based on all available data for both onland and offshore structures morphological and structural mapping satellite imagery and airphotographs remote sensing as well as the analysis of seismic profiles and the investigation of marine terraces and holocene raised notches along the island coasts for each fault we estimate and constrain some of the principal seismotectonic parameters and particularly the fault kinematics the cumulative amount of slip and the slip rate following simple assumptions and empirical relationships maximum expected magnitudes and mean recurrence periods are also suggested summing up the contribution to crustal extension provided by the two major fault sets we calculate both arc normal and arcparallel long term strain rates the occurrence of slightly deeper and more external low angle thrust planes associated with the incipient continental collision occurring in western crete is also analysed although these contractional structures can generate stronger seismic events m 7 5 they are probably much rarer and thus providing a minor contribution to the overall morphotectonic evolution of the island and the forearc a comparison of our geologicallybased results with those obtained from gps measurements show a good agreement therefore suggesting that the present day crustal deformation is probably active since middle quaternary and mainly related to the seismic activity of upper crustal normal faults characterized by frequent shallow 20 km moderate to strong seismic events seldom alternating with stronger earthquakes occurring along blind low angle thrust planes probably ramping from a deeper aseismic detachment ca 25 km this apparently contradicting co existence of juxtaposed upper tensional and lower compressional tectonic regimes is in agreement with the geodynamics of the region characterised by continental collision with nubia and the aegean mantle wedging

evaluating magnetic lineations ams in deformed rocks magnetic lineation in rocks is given by a cluster of the principal axes of maximum susceptibility kmax of the anisotropy of magnetic susceptibility ams tensor in deformed rocks magnetic lineations are generally considered to be the result of either bedding and cleavage intersection or they parallel the tectonic extension direction in high strain zones our ams determinations based on a variety of samples that were taken from mudstones slates and schists from the pyrenees and appalachians show that strain is not the only factor controlling the development of magnetic lineation we find that the development and extent to which the magnetic lineation parallels the tectonic extension direction depends on both the original ams tensor which in turn depends on the lithology and the deformation intensity rocks having a weak pre deformational fabric will develop magnetic lineations that more readily will track the tectonic extension

neotectonic evolution of the central betic cordilleras southern spain abstract paleostress orientations were calculated from fault slip data of 36 sites located along a traverse through the central betic cordilleras southern spain heterogeneous fault sets which are frequent in the area have been divided into homogeneous subsets by cross cutting relationships observed in the field and by a paleostress stratigraphy approach applied on each individual fault population the state of stress was sorted according to main tectonic events and a new chronology is presented of the miocene to recent deformation in the central part of the betic cordilleras the deviatoric stress tensors fall into four distinct groups that are regionally consistent and correlate with three late oligocene aquitanian to recent major tectonic events in the betic cordilleras the new chronology of the neotectonic evolution includes from oldest to youngest the following main tectonic phases 1 late oligocene aquitanian to early tortonian 1 subhorizontal n s partly e w directed 3 subvertical compressional structures thrusting of nappes large scale folding and strike slip faulting in the alboran domain and the external zone of the betic cordilleras 2 early tortonian to pliocene pleistocene 1 subvertical 3 subhorizontal nw se partly n s directed or e w directed radial extension large scale normal faulting in the central betic cordilleras and in the oldest neogene formations of the granada basin related to the gravitational collapse of the betic cordilleras and the exhumation of the intensely metamorphosed rock series of the internal zones at the same time formation of the alboran basin and intramontane basins such as the granada basin 3 pleistocene to recent 3a 1 subvertical 3 subhorizontal ne sw with prominent normal faulting but coevally 3b 1 subhorizontal nw directed 3 ne sw subhorizontal with strike slip faulting extensional structures and strike slip faulting are related to the ongoing convergence of the eurasian and african plates and coeval uplift of the betic cordilleras reactivation of pre existing fractures and faults was frequently observed phase 3 is interpreted as periodic strike slip and normal faulting events due to a permutation of the principal stress axes mainly 1 and 2

distinctive diamagnetic fabrics in dolostones evolved at fault cores the dead sea transform abstract we resolve the anisotropy of magnetic susceptibility ams axes along fault planes cores and damage zones in rocks that crop out next to the dead sea transform dst plate boundary we measured 261 samples of mainly diamagnetic dolostones that were collected from 15 stations to test the possible effect of the iron content on the ams we analyzed the fe concentrations of the samples in different rock phases dolostones with mean magnetic susceptibility value lower than 4 10 6 si and iron content less than 1000 ppm are suitable for diamagnetic ams based strain analysis the dolostones along fault planes display ams fabrics that significantly deviate from the primary sedimentary fabric the characteristics of these fabrics include well grouped sub horizontal minimum principal ams axes k 3 and sub vertical magnetic foliations commonly defined by maximum and intermediate principal ams axes k 1 and k 2 axes respectively these fabrics are distinctive along fault planes located tens of kilometers apart with strikes ranging between nnw sse and nne ssw and different senses of motion the obtained magnetic foliations k 1 k 2 are sub parallel within 20 to the fault planes based on rock magnetic and geochemical analyses we interpret the ams fabrics as the product of both shape and crystallographic anisotropy of the dolostones preferred shape alignment evolves due to mechanical rotation of subordinate particles and rock fragments at the fault core preferred crystallographic orientation results from elevated frictional heating 300 c during faulting which enhances c axes alignment in the cement supported dolomite breccia due to crystal plastic processes the penetrative deformation within fault zones resulted from the local fault related strain field and does not reflect the regional strain field the analyzed ams fabrics together with fault plane kinematics provide valuable information on faulting characteristics in the uppermost crust

identifying past earthquakes on carbonate faults advances and limitations of the rare earth element method based on analysis of the spili fault crete greece abstract recent work carcaillet et al 2008 manighetti et al 2010 has utilised a well established earthquake record on a normal fault in italy the magnola fault to successfully test a new method for identifying paleoearthquakes on carbonate rocks that of chemical analysis of their exhumed fault planes here we take the next natural step applying this novel method on a notionally active normal fault in greece the spili fault for which no paleoearthquake record exists despite the blind sampling data reveal an outstanding record of systematic fluctuations in the concentrations of rare earth elements ree and yttrium y upscarp which closely resemble those recorded on the magnola fault chemical analysis of 35 core samples extracted from a 10 m high section of the exhumed spili fault plane records upscarp depletion in the ree y concentrations at an average rate of ca 9 3 m depletion is overprinted by locally increased ree y concentrations upscarp a minimum of four such concentration fluctuations with wavelengths ranging from 0 5 to 3 m are recorded each fluctuation is interpreted to be generated by at least one paleoearthquake that episodically exhumed a zone of the fault plane each zone consists of an upper domain that is enriched in ree y and a lower un enriched domain ree y enrichment is due to the prolonged at least few 100 s of years contact of the limestone with the soil whereas the un enriched domain reflects instantaneous uplift from depths greater than the base of the soil during the same earthquake the ree y analytical method cannot resolve individual small sized earthquakes with slip less than the thickness of the soil cover and or individual large and small sized earthquakes which are clustered in time repeat time

geomorphology of active faulting and seismic hazard assessment new tools and future challenges by witold zuchiewicz and jerzy zasadni 2012 intended for this volume young tectonics of the outer western carpathians in the light of some morphometric indices in this paper we test the applicability of some morphometric indices commonly used in tectonic geomorphological studies to the area of the outer western carpathians representing an alpine fold and thrust belt this belt was shaped largely in miocene times and shows traces of pliocene quaternary tectonic activity consisting mainly in some remnant folding and faulting this is indicated by scarce examples of faulting within quaternary strata numerous cases of clast fracturing owing to palaeoearthquakes of relatively large magnitudes as well as warping and tilting of pleistocene and holocene strath terraces analysis of selected morphometric indices valley floor width valley height ratio riverbed gradients stream length gradient index basin elongation ratios and others conducted for the entire region and some chosen test areas in the westernmost part of the outer western ac c ep te d m an u sc r ip t accepted manuscript 24 carpathians proved their usefulness in detecting zones showing tendencies to young surface uplift however in the case of the stream length gradient index sl hack s index a word of caution should be added since the index is extremely sensitive to lithologic contrasts in the bedrock and its applicability to young tectonic analysis of fold and thrust belts appears to be strongly limited dr andrzej piotrowski apiot pgi gov pl szczecinie panstwowy instytut geologiczny szczecin poland and dr klaus reicherter rwth aachen university germany

strain variations in a seismogenic normal fault baza sub basin betic chain insights from magnetic fabrics ams abstract ams and structural analysis are here applied to study the deformed zone associated with a large scale active normal fault in the central betic cordillera spain namely the baza fault system to determine i the kinematics of structures and their relation with fault zone architecture and segmentation degree ii the correlation between deformational structures and the different types of magnetic fabrics and iii the evolution of magnetic fabrics patterns from sedimentary to shear related associated with normal faults five outcrops 969 samples were analysed along the fault trace which shows different degrees of segmentation along strike and strong localization of deformation along narrow fault zones a first main set of magnetic fabric data corroborates the normal kinematics of the baza fault showing magnetic lineations parallel to the dip slip transport direction a second secondary set of magnetic lineations is parallel to the intersection lineation and can be related to less intense deformation in the fault rocks furthermore a detailed study 523 samples of a trench excavated across the fault zone where two fault splays tend to coalesce in a linkage relay zone indicates that i lithology and distance to fault planes are two factors that control the development of extension related magnetic fabrics in weakly deformed sediments ii the development of shear related fabrics in fault zones entails the mechanical rotation of minerals iii different orientation of magnetic lineations are related to different intensity of bulk deformation and iv magnetic lineation is useful to define local deviations of deformation axes produced by changes in the local extension direction from fault perpendicular to fault parallel extension in the linkage zone between adjacent fault splays

ice loss processes in the seal nunataks ice shelf region from satellite altimetry and imagery the seal nunataks ice shelf snis 743 km 2 in 2013 is an unofficial name for a remnant area between the former larsen a and larsen b ice shelves off the northeastern antarctic peninsula analyses using landsat 7 etm and terra aster images from 2001 to 13 and icesat altimetry from 2003 to 09 show it has retreated and thinned following the larsen a 1995 and larsen b 2002 disintegrations despite some regional cooling and more fast ice since 2008 snis continues to lose ice along its margins and may be losing contact with some nunataks detailed analysis of data from four icesat tracks indicates that ice shelf thinning rates range between 1 9 and 2 7 m a 1 and generally increase from west to east an icesat repeat track crossing the adjacent robertson island shows a mean elevation loss of 1 8 m a 1 two tracks crossing the snis s remaining tributary rogosh glacier show sub meter elevation losses comparing shelf remnant and grounded ice thinning rates implies that basal ocean melting augments snis thinning by 1 m a 1 a rate that is consistent with other estimates of ocean driven shelf thinning in the region

the ad 365 crete earthquake and possible seismic clustering during the fourth to sixth centuries ad in the eastern mediterranean a review of historical and archaeological data abstract historical and archaeological data are used to test geological claims that in the fourth to sixth centuries ad the eastern mediterranean experienced an unusual clustering of destructive earthquakes the early byzantine tectonic paroxsym a review of historical accounts of a notable earthquake at this time that of 21 july ad 365 indicates that this event destroyed nearly all the towns in crete and was followed by a tsunami which devastated the nile delta the ad 365 event was also probably responsible for reported or observed destruction in ancient towns of west cyprus and libya this earthquake is most likely to be identified with a hellenic arc subduction zone event of great m 8 magnitude as testified by up to 9 m of uplift in western crete dated by previous geological studies to around this time historical and archaeological data also support the hypothesis that the fourth to sixth centuries ad was a period of abnormally high seismicity in the eastern mediterranean the high seismicity rates of this period may reflect a reactivation of all plate boundaries in the region dead sea transform east anatolian fault north anatolian fault hellenic arc cyprus arc fault

spatial and temporal variations in growth rates along active normal fault systems an example from the lazio abruzzo apennines central italy abstract the geometry kinematics and rates of active extension in lazio abruzzo italian apennines have been measured in order to gain a better understanding of the spatial and temporal variations in fault growth rates and seismic hazards associated with active normal fault systems we present fault map traces throws throw rates and slip directions for 17 parallel en echelon or end on active normal faults whose 20 40 km lengths combine to form a soft linked fault array ca 155 km in length and ca 55 km across strike throw rates derived from observations of faulted late glacial features and holocene soils show that both maximum throw rates and throw rate gradients are greater on centrally located faults along the strike of the array total throws and throw gradients show similar spatial variations but with weaker relationships with distance along strike when summed across strike throw rates are increasingly high towards the centre of the array relative to summed throws we interpret the above to suggest that throw rates have changed in the recent past ca 0 7 ma from spatially random fault growth rates initiating at 2 5 3 3 ma to growth rates that are greater on centrally located faults we interpret this as evidence for fault interaction producing throw rate variations that drive throw profile readjustment on these crustal scale soft linked faults the results are used to discuss seismic hazards in the region which are quantified in a second paper in this issue