interplay between subduction retreat and lateral extrusion tectonics of the western carpathians 1 analysis of brittle microstructures reveals three tertiary deformation events in the western carpathians 1 late paleogene bedding parallel extension 2 oligocene to middle miocene nne ssw compression and ese wnw extension 3 post mid miocene nw se extension these regional deformations applied to crustal blocks in the intra carpathian region resulted from forces which were induced by the coupled plate tectonic processes of subduction retreat beneath the carpathian arc and lateral extrusion from the eastern alps toward the carpathian region material flow from the alps spread toward east and ne guided by sinistral strike slip zones along the ne trending continental margin subduction retreat was terminated by mid miocene soft collision of the inner western carpathians with the european foreland ongoing subduction retreat beneath the eastern carpathians caused post mid miocene back arc extension forming the pannonian basin extension spread into the western carpathians by reactivating the extrusion related strike slip faults as normal faults

landslide recognition and mapping in a mixed forest environment from airborne lidar data abstract a precise accurate and complete landslide inventory is indispensable for the establishment of reliable landslide susceptibility and hazard maps in the preparation of landslide inventories dense vegetation cover is the major obstacle that confounds the topographic signature of landslides today the growing usage of light detection and ranging lidar technology in the field of geoscience illuminates the mystery of the landscapes cloaked in dense vegetation by providing a new visual acuity to researchers turkey similar to many mid latitude mountainous countries suffering from landslides is still continuing landslide inventory mapping with conventional methods such as aerial photo interpretations api although 68 of landslide events occurred under dense forest cover in the north of the country despite the country wide medium scaled landslide catalogs the number and the abundance of landslides covered by forests remain largely unknown regardless of the increasing availability of high resolution remote sensing data from these motivating insights and drawbacks the study s focus is to evaluate the capability of mapping landslides by visually analyzing airborne lidar dtm derivatives and compare the results with the 1 25 000 scaled api based inventory to understand the potential contribution of lidar technology in europe s deadliest country turkey in terms of landslides the landslide mapping results for a test area located in the densely forested ulus basin western black sea region reveal that the extent and the number of the mapped landslides n 902 from the airborne lidar data are much higher than those of the available api based landslide inventory which includes 67 landslides comparative analysis on topographic signatures of landslides is also underpinned on a distinct discrepancy of slope failure diagnostic indicators captured by the two available dems derived from lidar and 1 25 000 scaled topographic maps emphasizing the success rate of lidar derived dem in recognition and mapping landslides with higher precision and accuracy together with all analysis results the landslide recognizability degree assessment based on the forest cover percentage and slope height differences of landslides highlights that the lidar data enable landslides to be defined up to 100 m2 while this value is 20 times lower than that of estimated values from api based landslides in addition to underlining the contribution of lidar technology to the recognition of landslides hidden under dense vegetation these findings stress the importance of lidar data on complete and accurate landslide inventories for production of reliable susceptibility and hazard maps and further a better understanding of the landslide processes and reducing related losses

the 2001 adana landslide and its destructive effects turkey the current study deals with a catastrophic landslide that occurred due to heavy rainfall in adana southern turkey in 2001 the research area which is one of the largest populated districts in adana and one of the most tropical places between the middle east and southern europe has about 25 000 people on the basis of geological and geotechnical surveys the landslide phenomena and the effects of landslide are examined to understand the slide mechanism of the landslide ground reconnaissance laboratory and in situ tests are conducted it is observed that the clayey and silty layers of the site are heavily saturated due to extreme rainfall in winter and consequently sheared the landslide consists of a block sliding in the upper portions and a debris flow soil flow component around the margins of the sliding blocks in the middle parts and at the toe although there was no loss of human life it has caused significant economic losses besides it is determined that if precautions are not taken around the landslide area larger landslides could definitely occur in the future

evaluation of different machine learning models for predicting and mapping the susceptibility of gully erosion abstract gully erosion constitutes a serious problem for land degradation in a wide range of environments the main objective of this research was to compare the performance of seven state of the art machine learning models svm with four kernel types bp ann rf and brt to model the occurrence of gully erosion in the kashkan poldokhtar watershed iran in the first step a gully inventory map consisting of 65 gully polygons was prepared through field surveys three different sample data sets s1 s2 and s3 including both positive and negative cells 70 for training and 30 for validation were randomly prepared to evaluate the robustness of the models to model the gully erosion susceptibility 12 geo environmental factors were selected as predictors finally the goodness of fit and prediction skill of the models were evaluated by different criteria including efficiency percent kappa coefficient and the area under the roc curves auc in terms of accuracy the rf rbf svm brt and p svm models performed excellently both in the degree of fitting and in predictive performance auc values well above 0 9 which resulted in accurate predictions therefore these models can be used in other gully erosion studies as they are capable of rapidly producing accurate and robust gully erosion susceptibility maps gesms for decision making and soil and water management practices furthermore it was found that performance of rf and rbf svm for modelling gully erosion occurrence is quite stable when the learning and validation samples are changed

the 17 march 2005 kuzulu landslide sivas turkey and landslide susceptibility map of its near vicinity landslides are common natural hazards in the seismically active north anatolian fault zone of turkey although seismic activity heavy rainfall channel incisions and anthropogenic effects are commonly the main triggers of landslides on march 17 2005 a catastrophic large landslide in sivas northeastern of turkey the kuzulu landslide was triggered by snowmelt without any other precursor the initial failure of the kuzulu landslide was rotational following the rotational failure the earth material in the zone of accumulation exhibited an extremely rapid flow caused by steep gradient and high water content the agnus creek valley where kuzulu village is located was filled by the earth flow material and a landslide dam was formed on the upper part of agnus creek the distance from the toe of the rotational failure down to the toe of the earth flow measured more than 1800 m with about 12 5 million m3 of displaced earth material the velocity of the kuzulu landslide was extremely fast approximately 6 m s the main purposes of this study are to describe the mechanism and the factors conditioning the kuzulu landslide to present its environmental impacts and to produce landslide susceptibility maps of the kuzulu landslide area and its near vicinity for this purpose a detailed landslide inventory map was prepared and geology slope aspect elevation topographic wetness index and stream power index were considered as conditioning factors during the susceptibility analyses the conditional probability approach was used and a landslide susceptibility map was produced the landslide susceptibility map will help decision makers in site selection and the site planning process the map may also be accepted as a basis for landslide risk management studies to be applied in the study area

multiarchive paleoseismic record of late pleistocene and holocene strong earthquakes in switzerland a multiarchive approach has been applied to the investigation of the late pleistocene and holocene record of strong earthquakes in switzerland the geological archives used for this study include active faults lake deposits slope instabilities and caves in the basle area eight trenches were opened across the basle reinach fault nearby rockfall deposits were systematically investigated sediment cores were taken from two lakes and nine caves were studied in central switzerland five lakes were investigated by means of high resolution seismic lines and sediment cores furthermore three caves were studied in central switzerland altogether the investigations are based on more than 350 km of high resolution reflection seismic lines 450 m of core samples 260 m of trenches and 245 radiocarbon age determinations the measured co seismic displacements along the basle reinach fault supply independent information for the magnitude of the ad 1356 basle earthquake exclusively based on geological evidence deformation features related to three well documented strong historic earthquake shocks were identified deformation features of the ad 1774 altdorf and ad 1601 unterwalden earthquakes can be used to calibrate paleoseismic evidence in central switzerland altogether traces of 13 earthquakes could be found in the two study areas all of them with magnitudes mw 6 or greater for the first time the earthquake catalogue for switzerland can be extended back beyond historic records into the late pleistocene spanning 15 000 years d 2005 elsevier b v all rights reserved

exhumation of the ultrahigh pressure continental crust in east central china cretaceous and cenozoic unroofing and the tan lu fault the orogenic architecture of the world s largest ultrahigh pressure exposure the hong an dabie mountains of the triassic qinling dabie orogenic belt is dominated by cretaceous and cenozoic structures that contributed to its exhumation from 30 km depth cretaceous magmatic crustal recycling 50 for the entire dabie and heating 250 to 700 c were most prominent in dabie and exhumation magmatism and cooling were all controlled by cretaceous transtension exhumation was accomplished principally by an asymmetric cordilleran type extensional complex in the northern dabie northern orthogneiss unit between 140 and 120 ma at rates as fast as 2 mm yr and average horizontal stretching rates of up to 6 mm yr cretaceous reactivation occurred within a regional transtensional strain field as a result of far field collisions and pacific subduction the onset of crustal extension was preceded and possibly facilitated by a reheating of the hong an dabie crust 140 ma coeval with the onset of voluminous magmatism in eastern china 145 ma which resulted from a change in pacific subduction from highly oblique to orthogonal the tan lu continental scale fault was a normal fault zone in the mid cretaceous 110 90 ma and underwent 5 4 km dip slip and 4 km throw in the cenozoic during the india asia collision the qinling dabie belt acted as the structural discontinuity between the strike slip dominated escape tectonics south of the qilian qinling dabie belt and the rifting dominated tectonism north of it the most prominent cretaceous and cenozoic structures of the hong an dabie the xiaotian mozitang and the jinzhai fault zones respectively reactivated major lithospheric structures of the triassic orogen i e the huwan detachment zone and the suture

geological evolution of the late mesozoic continental margin of northwestern anatolia abstract the armutlu peninsula is a composite tectonic entity made up of sections of the sakarya continent the rhodope pontide fragment and an ophiolite these were assembled following a continental collision between gondwanaland and laurasia during the late cretaceous the northern margin of the sakarya continent underwent progressively increasing deformation prior to and during the advancing collision due to continued convergence between the two continents initially the leading edge of the continent subsided under the load of an approaching ophiolitic slab following this a north directed thrusting and folding occurred during the turonian progressive elimination and eventual closure of the ocean preceded the thrusting of northerly situated collisiondashinduced nappe packages over the leading edge of the sakarya continent the nappe laden edge of the continental margin then collapsed and steadily subsided under the heavy load of the ophiolitic slab and the northern continental fragment consequently the nappe packages and the ophiolite were collectively metamorphosed during the coniaciandashsantonian interval during the subsidence the main body of the sakarya continent partially detached from its collapsed edge along a fault zone and thus suffered an independent but less severe deformation which lasted until the uplift of the collapsed edge in the campanian from the late campanian onward throughout later orogenic stages the metamorphic and nondashmetamorphic units amalgamated into a single tectonic entity forming a basement for younger cover rocks

a multistory gigantic subaerial debris flow in an active fault scarp in nw anatolia turkey anatomy mechanism and timing mass instability in the uplifting footwall blocks of normal faults involves a range of regional and local factors including among others climatic setting topography lithology and particularly ground shaking during earthquakes morphological and sedimentological investigations backed by 14c dating on a huge debris flow and its zone of depreciation provided favorable insights for dynamics and causative factors of this mass wasting our observations showed that ismetpasa debris flow with a volume of 96 km 3 involves three individual flows of decreasing significance in the late pleistocene holocene period the primary flow occurred in relation to a huge landslide developed on highly fractured and altered basaltic lavas near the crest of fault scarp c 18 7 ka bp and probably conditioned by high precipitation rates in the early interglacial although most of the blocky debris flow transferred into the neighboring graben to form a 2 km wide debris fan some remnant blocks and flow induced valley side slick

determination of stress from slip data faults and folds a new technique is derived to invert slickenside data for the stress field that caused the faulting episode this inversion is simplified by the assumption that the magnitude of the tangential traction on the various fault planes at the time of rupture is similar study of three normal faulting regimes shows that the inversion derived with this assumption yields results that closely match older inversions that did not include the assumption hence the assumption may be valid and is shown to be justified by analyzing a simple fracture criterion application of slip data inversions is extended from faulting regimes to the slip on bedding plane faults in folding regimes comparison of the inversion results with the geometry of the folds shows this application to be successful greatly increasing the number of data sets that can be used to find the paleostress field

kinematic history of the narragansett basin massachusetts and rhode island constraints on late paleozoic plate reconstructions the formation of the narragansett basin of rhode island and massachusetts and the polyphase deformation geometry of the pennsylvanian age basin sediments can be explained by collision and strike slip interactions between an avalonian microcontinent the european north american plate and the african plate during the late paleozoic sinistral movement between an avalonian microcontinent and the european north american plate resulted in formation of pull apart basins subsequently africa moved toward north america along an east west trending dextral megashear zone and collided with the eastern margin of southern north america the narragansett basin is located on the avalonian microcontinent near the suture with the north american continent and in the transition zone between the megashear and the collision tectonic regimes the basin shape stratigraphy and sedimentary relationships can be explained by the coalescence of two composite grabens which formed at different times the thicker northern graben is only affected by one deformation whereas the southern graben shows evidence of four distinct phases of postrifting deformation the first two coaxial folding deformations of the basin sediments are attributed to the closure of the basin complex during collision of africa and north america the third and fourth deformations are interpreted as sinistral r riedal and dextral shears respectively associated with the east west trending megashear system a prograde barrovian metamorphic front started in the western portion of the southern graben slightly after the first deformation and migrated northward and eastward where it is synchronous with the second deformation

the pieniny klippen belt in the western carpathians of northeastern slovakia structural evidence for transpression abstract the pieniny klippen belt represents a 600 km long but only a few kilometers wide suture zone in the carpathian orogenic belt based on a quantitative analysis along a part of its nw trending segment in northeastern slovakia we present structural data supporting transpression the continuous interaction of strike slip shearing horizontal shortening and vertical lengthening as a major deformation style in its polyphase deformation history dextral transpression is expressed in the map scale and outcrop fault pattern the oblique orientation of fold axes to the faults bounding the klippen belt and extension parallel to the fold axes the transpression related strain field is described and quantified by the analysis of 1 orientation of rotated fold axes displaying an acute angle to the margins of the klippen belt 2 orientation and geometry of paleostress derived from mesoscale fault striae analysis e trend of 3 trajectories and flattening geometry and 3 the deformation history indicated by extension veins non coaxial regime different techniques using fault striae data quantify paleostress and subdivide heterogeneous data sets mathematically into homogeneous subsets the observed deformation history is modelled as a homogeneous transpression deformation the best fitting model requires a nw trending present day orientation external contraction direction e g plate slip vector and predicts 16 fold axes parallel extension and 23 axial plane normal shortening

possible paleostress tensor configurations derived from fault slip data in eastern vermont and western new hampshire the configuration of six possible paleostress tensors have been derived from 152 faults measured in eastern vermont and western new hampshire populations of potentially genetically related faults were separated using two techniques tensor configurations for each population were derived using a linear least squares inversion method based in part on the work of reches 1987 and a grid search inversion method which tests over 100 000 possible tensors for compatibility with all or portions of the data faults belonging to the oldest population set r n 24 occur primarily in high grade rocks this set is composed of semiductile northeast trending reverse and west northwest trending left lateral faults fault fabrics of quartz rods and thin mylonite layers suggest that the host rocks were at crustal levels of 8 10 km during faulting the derived tensor indicates a roughly east west 1 and near vertical 3 set r faults are offset by normal faults sets n1 and n2 and are interpreted to be pre mesozoic in age perhaps related to late paleozoic alleghanian compression normal and normal oblique faults mineralized with chlorite calcite and strained quartz n 73 have been separated into two populations sets n1 n 49 and n2 n 24 even though these faults are likely of similar age host rocks were probably at moderate crustal depths of perhaps 5 km during faulting faults of both sets are most likely related to mesozoic rifting tensor configurations indicate that 1 plunges steeply northwest n1 and southeast n2 and 3 plunges gently roughly east west these faults cut presumably mesozoic age dikes and are themselves offset by normal oblique faults set t and right lateral faults set rl strongly deviatoric near vertical 1 suggests a thermally driven tectonic regime during the development of normal faulting in new england set t n 25 is composed of normal oblique slip faults mineralized similarly as sets n1 and n2 the plunge of 1 is 50 n and 3 plunges gently east field relations indicate set t faults document the transition from normal sets n1 and n2 to strike slip faulting regimes set rl a compatible sequence of mesozoic stress fields is suggested de boer et al 1988 north northeast trending right lateral faults of set rl n 7 are mineralized with quartz limonite calcite chlorite calcite twins are bent and fractured and quartz grains show minor internal strain suggesting that these faults developed while host rocks were at relatively shallow crustal levels the plunge of 1 is gently northeast and 3 plunges gently east southeast seven distinctly mineralized feldspar siderite quartzoalcite 1imonite chlorite gently northwest dipping thrust faults of set f define the sixth tensor these faults are cut by essentially vertical east side up faults and are assumed to be mesozoic in age by analogy with similar faults in western massachusetts

morphology displacement and slip rates along the north anatolian fault turkey 1 geological and geomorphological offsets at different scales are used to constrain the localization of deformation total displacement and slip rates over various timescales along the central and eastern north anatolian fault naf in turkey the naf total displacement is reevaluated using large rivers valleys 80 15 km and structural markers pontide suture 85 25 km tosya vezirkopru basins 80 10 km these suggest a neogene slip rate of 6 5 mm yr over 13 myr the river network morphology shows offsets at a range of scales 20 m to 14 km across the main fault trace and is also used to estimate the degree to which deformation is localized at a smaller scale the morphology associated with small rivers is offset by 200 m along the naf the age of these features can be correlated with the holocene deglaciation and a slip rate of 18 3 5 mm yr is determined this is consistent with a rate of 18 5 mm yr deduced independently from the 14c dating of stream terrace offsets over the short term gps data gives a similar rate of 22 3 mm yr all our results tend to show that most of the deformation between the anatolian and eurasian lithospheric plates has been accommodated along or very close to the active trace of the naf the difference between the neogene and the holocene slip rate may be due to the recent establishment of the current plate geometry after the creation of the naf

stress and timing relationships of a fault related paleohydrothermal system in central new hampshire record of a mesozoic stress change in new england a mineral assemblage comprised of chalcedony drusy quartz and very fine grained iron hydroxide limonite with or without blocky calcite qfc coats joint surfaces fills fractures and commonly occurs as pressure shadow encrustations on brittle fault surfaces in central new hampshire but only occurs sporadically in other areas of new england locally qfc includes silicified breccias of highly altered host and euhedral quartz crystal fragments suspended in a matrix of chalcedony and limonite one hundred and four brittle faults from central new hampshire mineralized with qfc can be separated into two families set n is composed of primarily north northeast to northeast trending steeply dipping normal faults n 61 and set s is composed of north northwest to north northeast trending steeply dipping primarily right lateral strike to normal oblique slip faults n 43 these two sets of faults are thought to record two paleostress conditions the extension direction for both tensors plunges gently east southeast but the compression direction is near vertical for set n and trends roughly northeast plunging 30 for set s fault slip inversion suggests that set n faults are best fit with 1 most deviatoric 2 3 set s is best fit with 3 most deviatoric 1 2 and low values for fault plane coefficient of friction and or high fluid pressure qfc occurs in the 158 ma belknap mountain complex of the white mountain magma series and is thought to have developed at relatively shallow crustal levels based on the assemblage nature of fluid inclusions and association of qfc as brittle fault and fracture filling mineralization occurrence of qfc in the 158 ma belknap mountain complex paleostress implications of qfc mineralized brittle faults and range and character of fault fabrics in the belknap units suggests that qfc developed around the time of belknap intrusion and cooling and that late jurassic to early cretaceous is the approximate time at which a regional change in paleostress conditions occurred in new england this age and nature of the paleostress change is in accord with a change postulated by de boer et al 1988

late cretaceous deformation of the pieniny klippen belt west carpathians abstract the late cretaceous position and dynamics of the pieniny klippen belt of the west carpathians which lies behind the palaeogene flysch accretionary prism are reconstructed as shown by the reconstruction based on structural sedimentological and palaeomagnetic data the pieniny klippen belt occupied a wnw ese to nw se trending zone during the late cretaceous which acted as an oblique convergent boundary between the ancestral west carpathians and the oceanic lithosphere attached to the north european platform sediments of the pieniny klippen belt were part of both the mountain belt and foredeep at that time known change from pelagic micritic limestone to a flysch sequence is progressively younger seawards in the thrust slice stack forming the pieniny klippen belt the syn sedimentary record includes flysch olistostrome and wildflysch sediments both the nw se thrusting along the ne sw striking faults and dextral strike slip faulting along the wnw ese to nw se striking faults were active in the late cretaceous in the area of the current pieniny klippen belt

surface deformation related to the 2008 wenchuan earthquake and mountain building of the longmen shan eastern tibetan plateau abstract the 12 may 2008 ms 8 0 wenchuan earthquake china was one of largest continental thrusting events worldwide based on interpretations of post earthquake high resolution remote sensing images and field surveys we investigated the geometry geomorphology and kinematics of co seismic surface ruptures as well as seismic and geologic hazards along the longmen shan fold and thrust belt our results indicate that the wenchuan earthquake occurred along the ne sw trending yingxiu beichuan and guanxian anxian faults in the longmen shan fold and thrust belt the main surface rupture zones along the yingxiu beichuan and guanxian anxian fault zones are approximately 235 and 72 km in length respectively these sub parallel ruptures may merge at depth the yingxiu donghekou surface rupture zone can be divided into four segments separated by discontinuities that appear as step overs or bends in map view surface deformation is characterized by oblique reverse faulting with a maximum vertical displacement of approximately 10 m in areas around beichuan county earthquake related disasters e g landslides are linearly distributed along the surface rupture zones and associated river valleys the wenchuan earthquake provides new insights into the nature of mountain building within the longmen shan eastern tibetan plateau the total crustal shortening accommodated by this great earthquake was as much as 8 5 m with a maximum vertical uplift of approximately 10 m the present results suggest that ongoing mountain building of the longmen shan is driven mainly by crustal shortening and uplift related to repeated large seismic events such as the 2008 wenchuan earthquake furthermore rapid erosion within the longmen shan fold and thrust belt occurs along deep valleys and rupture zones following the occurrence of large scale landslides triggered by earthquakes consequently we suggest that crustal shortening related to repeated great seismic events together with isostatic rebound induced by rapid erosion related unloading is a key component of the geodynamics that drive ongoing mountain building on the eastern tibetan plateau

seismotectonics of the armutlu peninsula marmara sea nw turkey from geological field observation and regional moment tensor inversion abstract the armutlu peninsula located in the eastern marmara sea coincides with the western end of the rupture of the 17 august 1999 izmit mw 7 6 earthquake which is the penultimate event of an apparently westward migrating series of strong and disastrous earthquakes along the nafz during the past century we present new seismotectonic data of this key region in order to evaluate previous seismotectonic models and their implications for seismic hazard assessment in the eastern marmara sea long term kinematics were investigated by performing paleo strain reconstruction from geological field investigations by morphotectonic and kinematic analysis of exposed brittle faults short term kinematics were investigated by inverting for the moment tensor of 13 small to moderate recent earthquakes using surface wave amplitude spectra our results confirm previous models interpreting the eastern marmara sea region as an active transtensional pull apart environment associated with significant nne ssw extension and vertical displacement at the northern peninsula long term deformation pattern did not change significantly since pliocene times contradicting regional tectonic models which postulate a newly formed single dextral strike slip fault in the marmara sea region this area is interpreted as a horsetail splay fault structure associated with a major normal fault segment that we call the waterfall fault apart from the waterfall fault the stress strain relation appears complex associated with a complicated internal fault geometry strain partitioning and reactivation of pre existing plane structures at the southern peninsula recent deformation indicates active pull apart tectonics constituted by ne sw trending dextral strike slip faults earthquakes generated by stress release along large rupture zones seem to be less probable at the northern but more probable at the southern peninsula additionally regional seismicity appears predominantly driven by plate boundary stresses as transtensional faulting is consistent with the southwest directed far field deformation of the anatolian plate

structural model of the central longmen shan thrusts using seismic reflection profiles implications for the sediments and deformations since the mesozoic abstract the structural setting and deformation history are very important aspects of understanding the frequent earthquakes and assessing the hazards in this paper we interpret two new seismic profiles that were collected after the wenchuan mw7 9 earthquakes occurred on may 2008 our interpretation has integrated four wells three seismic profiles and the surface geology to reveal structural characteristics of the central longmen shan thrust the drilled wells reveal that there are two detachments within the upper triassic and the lower triassic at the longmen shan thrusts the shallow detachment fault transferred its slip to the basin and made another deformation inner the sichuan basin between the shallow detachments many faults developed and the major structures at the thrust front have formed as structural wedges both the drilled wells and seismic interpretation show the upper triassic repeated in the depth the shortening at the central longmen shan thrust is approximately 30 37 according to geological survey and the seismic interpretation the foreland basin was developed during the late triassic and the angular unconformity between the lower jurassic and the upper triassic at the longmen shan front several different tectonic events can be identified since the mesozoic which indicated that the longmen shan has a complex evolution history in our model the major beichuan fault f2 and the pengguan fault f3 at the central longmen shan dip steeply near the surface but are more gentle dipping at depth both of the shallow thrusting and the basement shortening made contribution to the rapid uplift of the longmen shan during the cenozoic the co seismic ruptured fault is like a branchy fault that developed on the major fault system the wenchuan mw7 9 earthquake and the lushan mw6 7 earthquake may be related to the reaction of the basement structures

fault slip inversions their importance in terms of strain heterogeneity and kinematics of brittle deformation abstract heterogeneous deformation is intrinsic in natural deformation but often underestimated in the analysis and interpretation of mesoscopic brittle shear faults based on the analysis of 11 222 faults from two distinct tectonic settings the central andes in argentina and the sudbury area in canada interpolation of principal strain directions and scaled analogue modelling we revisit controversial issues of fault slip inversions collectively adhering to heterogeneous deformation these issues include the significance of inversion solutions in terms of 1 strain or paleo stress 2 displacement notably plate convergence 3 local versus far field deformation 4 strain perturbations and 5 spacing between stations of fault slip data acquisition furthermore we highlight the value of inversions for identifying the kinematics of master fault zones in the absence of displaced geological markers a key result of our assessment is that fault slip inversions relate to local strain not paleo stress and thus can aid in inferring the kinematics of master faults moreover strain perturbations caused by mechanical anomalies of the deforming upper crust significantly influence local principal strain directions thus differently oriented principal strain axes inferred from fault slip inversions in a given region may not point to regional deformation caused by successive and distinct deformation regimes this outcome calls into question the common practice of separating heterogeneous fault slip data sets into apparently homogeneous subsets finally the fact that displacement vectors and principal strains are rarely co linear defies the use of brittle fault data as proxy for estimating directions of plate scale motions

an inverse problem in microtectonics for the determination of stress tensors from fault striation analysis abstract a method is proposed to compute some characteristics of a possible stress tensor related to striations measured in a given faulted area if several tectonic phases are responsible for the striations the method separates and determines the successive stress tensors the iterative algorithm consists of alternatively a sorting the data attributed to a tectonic phase and b computing the characteristics of the stress tensor of this phase the method is tested using an application to synthetic and actual data

stress transmission across an active plate boundary an example from southern mexico abstract paleostress tensors calculated from inversion of fault slip data at 60 stations between zihuatanejo and tehuantepec in southern mexico were separated into four distinct groups and assigned to time intervals between 150 ma and recent the change in orientation of the maximum horizontal stress closely traces the change in direction of convergence between the north american and the farallon cocos plates for the same time interval depending on the angle between the convergence direction and the plate margin both thrust fault and strike slip stress regimes were active based on this comparison we infer that the stress distribution in the continental crust of southern mexico has been controlled by interplate stress transmission latest cretaceous early tertiary mylonites at the northern edge of the xolapa complex portray left lateral oblique crustal extension and oceanward migration of the upper plate the orientation of extension at mid crustal level grossly correspond to the orientation of the minimum compressive stress at upper crustal level during the last 20 ma a tensional stress regime as a response to surface uplift has been dominant in southern mexico

favoured states of palaeostress in the earth s crust evidence from fault slip data abstract in a major survey of published palaeostress estimates obtained by the use of fault slip data over 2000 stress tensors from shallow crustal levels have been compiled the results are derived from regions where deformation is dominated by brittle processes and consist of incomplete stress tensors in which the orientations of the principal stresses 1 2 3 are known together with the stress ratio 2 3 1 3 the orientations of the stress axes display a preferred orientation with a tendency for one of the axes to be vertical this accords with anderson s assumed standard state stress configuration near to the earth s free surface although the tendency is strong there are frequent deviations from the arrangement in 25 of cases the steepest stress axis deviates by more than 25 from the vertical in undertaking studies of palaeostress it would be therefore unwise to use methods that assume a priori one vertical stress axis unless previous local results indicate this to be the case normal strike slip and thrust stress arrangements with 1 2 and 3 as the steepest stress respectively occur in the database with frequencies approximately in the ratio 2 2 1 in the compiled results the raw stress ratios which have a theoretical range from 0 to 1 show a lack of very high values and to a lesser extent very low values this suggests that triaxial stress states are more common than axial compression deviatoric stress and axial tension deviatoric stress however this relative abundance of triaxial stress states is considered to be a natural feature of a uniform distribution of stress tensors in addition there is a marked bias in the collated ratios towards values less than 0 5 and this is expressed by an overall mean of 0 39 several possible explanations for the distribution of stress ratios are discussed these explanations are related to the tendency for tectonic deformation to be of plane strain type coupled with volume change and to the fact that gravitational loading makes an important contribution to the state of stress in the crust

susceptibility assessments of shallow earthflows triggered by heavy rainfall at three catchments by logistic regression analyses abstract sometimes regional meteorological anomalies trigger different types of mass movements in may 1998 the western black sea region of turkey experienced such a meteorological anomaly numerous residential and agricultural areas and engineering lifelines were buried under the flood waters besides the reactivation of many previously delineated landslides thousands of small scale landslides mostly the earthflow type occurred all over the region the earthflows were mainly developed in flysch type units which have already presented high landslide concentrations in this study three different catchments namely agustu egerci and kelemen were selected because they have the most landslide prone geological units of the region the purposes of the present study are to put forward the spatial distributions of the shallow earthflows triggered to describe the possible factors conditioning the earthflows and to produce the shallow earthflow susceptibility maps of the three catchments the unique condition units ucu were employed during the production of susceptibility maps and during statistical analyses the unique condition units numbered 4052 for the agustu catchment 13 241 for the egerci catchment and 12 314 for the kelemen catchment the earthflow intensity is the highest in the agustu catchment 0 038 flow ucu and lowest in the egerci catchment 0 0035 flow ucu logistic regression analyses were also employed however during the analyses some difficulties were encountered to overcome the difficulties a series of sensitivity analyses were performed based on some decision rules introduced in the present study considering the decision rules the proper ratios of ucu free from earthflow 0 ucu including the earthflow 1 for the agustu egerci and kelemen catchments were obtained as 3 6 and 5 respectively also a chart for the proper ratio selection was developed the regression equations from the selected ratios were then applied to the entire catchment and the earthflow susceptibility maps were produced the landslide susceptibility maps revealed that 15 of the agustu catchment 8 of the egerci catchment and 7 of the kelemen catchment have very high earthflow susceptibility and most of the earthflows triggered by the may 1998 meteorological event were found in the very high susceptibility zones

transition from convergence to escape field evidence from the west carpathians abstract the tertiary deformation of the west carpathians occurred during northeast directed convergence of the european and apulian plates and was complicated by space constraints imposed by orogen advance palaeostress fields computed from fault slip data and structural interpretation of known gravimetric magnetic seismic palaeomagnetic lithostratigraphic sedimentological fission track and borehole data indicate that during deformation the orogen consisted of both frontal thrust stacking zones and internal extensional trans tensional zones synthesis of available data indicates that the episodes of tectonism in litho tectonic units were both time and plate position related and were caused by conditions which varied in different areas ranging from the foreland to back arc region in each time period discrete deformation phases record the transition from convergent to tectonic escape tectonisrn principal horizontal stress trajectories were approximately co linear with the plate convergence vectors prior to escape the onset of escape conditions is indicated by 1 clockwise rotation of palaeostress orientations during the time of known escape in the eastern alps and 2 the cessation of thrusting of the flysch belt nappes onto the neogene foredeep in the westernmost part of the west carpathians tectonic escape along strike slip faults subparallel to the collision suture zone began in early badenian time in the west carpathians various regions along the orogenic belt were affected by escape that became progressively younger towards the east this agrees with the observations of various authors that the final phase of thrusting towards the european platform became younger to the east along the west carpathian arc in addition palaeostress trajectory patterns for various periods are similar to those modelled by a rigid block indenting a viscous half space an attempt is made to complete the mosaic of information on the cenozoic evolution of the alpine carpathian pannonian area which in the models given by ratschbacher royden horvath bergerat and others is based on extrapolated data the object is to detail the timing and complexity of the local time and plate position related mechanisms in the context of the entire orogen in order to update previous rather simplified models

near surface in situ stress 3 correlation with microcrack fabric within the new hampshire granites we studied the correlation between near surface in situ stress and the preferred orientation of microcracks at two quarries in the milford granite and one quarry in the conway granite new hampshire the orientation of in situ stress was determined by overcoring doorstoppers and from the strike of induced borehole fractures produced by a pressurized packer the preferred orientation of vertical microcracks was determined using ultrasonic measurements to determine p wave velocity vp on core and in situ and from thin section analyses in situ vp anisotropy was determined from interborehole travel time data at all three sites directions of maximum compressive stress 1 and induced borehole fractures are aligned with the preferred orientation of open microcracks determined from core vp and thin section data an analysis of the microcracking sequence within each pluton suggests 1 that the quarry grain resulted from cooling induced thermal stresses and 2 a method of distinguishing the paleostress axes at the time of cooling from contemporary stress

a stress inversion procedure for polyphase fault slip data sets palaeostress estimation from striated fault data is frequently frustrated by the fact that natural fault data are heterogeneous in the sense that they cannot satisfactorily be explained by reactivation brought about by a single stress tensor in many instances there is clear evidence to show that striation data can record the effects of multiple stress events any attempt to find the tensor which best fits or explains such dynamically mixed data sets risks determining a spurious stress state which is some form of compromise between the real stress states corresponding to different tectonic phases to avoid this problem a strategy is proposed here which involves an initial separation of the raw data into coherent sub sets prior to formal stress inversion this separation is performed by assigning attributes to each fault which describe the fault s compatibility with trial stress tensors using these attributes faults can be grouped into dynamically homogeneous families using the statistical techniques of cluster analysis

appalachian carboniferous dextral strike slip faults an example from brookneal virginia the northern appalachian dextral fault system of late paleozoic age is also present in the central and southern appalachians an example of a dextral strike slip fault is the 4 km wide brookneal shear zone in the southwest virginia piedmont the shear zone is in part superimposed on the melrose granite where an s c mylonite was produced by dynamic recrystallization of all constituent minerals the arvonia metasedimentary and charlotte belt metavolcanic rocks contain spaced dextral shear bands at a consistent 24 3 to the shear zone boundary a minimum displacement estimate of 17 km was obtained from rotated foliation measurements in the melrose granite the age of movement on the brookneal shear zone has been constrained by isotopic dating to between 324 and 300 ma other faults in the southern appalachians including the nutbush creek and modoc zones show similar ages and relative offsets possible plate tectonic models that could account for the late paleozoic dextral fault system throughout the appalachians include 1 tectonic escape resulting from the collision of a plate with north america to the north of the canadian appalachians 2 postcollision interplate readjustments involving counterclockwise rotation of africa relative to north america and 3 oblique convergence of eastern north america with an oceanic plate moving west

back analysis of a seismically induced highway embankment failure during the 1999 duzce earthquake an earthquake of magnitude 7 2 on the richter scale occurred on 12 november 1999 in the duzce bolu region of turkey the region was also hit approximately 3 months before during the devastating kocaeli earthquake of 17 august 1999 besides high casualties and damage to various engineering structures and buildings slope and embankment failures on the highway and the country roads occurred in this study the authors are concerned with the back analysis of an embankment failure that occurred on the four lanes e 5 highway connecting ankara to istanbul at bakacak in the bolu province during the 1999 duzce earthquake both pseudo dynamic and dynamic limiting equilibrium methods are used to back analyse the conditions for the initiation of failure and also displacement responses of the embankment during the earthquake shaking after having given a brief summary of the investigations on the post failure state the geology and geotechnical characteristics of the site and the dynamic limiting equilibrium method developed and used for analyses are described the results of the back analysis based on a pseudo dynamic approach revealed that the maximum ground acceleration to initiate the failure of the embankment was probably about 0 125 g on the other hand the application of a method for computing the displacement and velocity responses of the failed embankment showed that the failure was possible when the embankment was subjected to ground accelerations similar to that recorded at the duzce station in addition the computations also revealed that the time history of accelerations could be very important for the failure of slopes and embankments

landslide susceptibility mapping using frequency ratio analytic hierarchy process logistic regression and artificial neural network methods at the inje area korea every year the republic of korea experiences numerous landslides resulting in property damage and casualties this study compared the abilities of frequency ratio fr analytic hierarchy process ahp logistic regression lr and artificial neural network ann models to produce landslide susceptibility index lsi maps for use in predicting possible landslide occurrence and limiting damage the areas under the relative operating characteristic roc curves for the fr ahp lr and ann lsi maps were 0 794 0 789 0 794 and 0 806 respectively thus the lsi maps developed by all the models had similar accuracy a cross tabulation analysis of landslide occurrence against non occurrence areas showed generally similar overall accuracies of 65 27 64 35 65 51 and 68 47 for the fr ahp lr and ann models respectively a correlation analysis between the models demonstrated that the lr and ann models had the highest correlation 0 829 whereas the fr and ahp models had the lowest correlation 0 619

landslide inventory maps new tools for an old problem landslides are present in all continents and play an important role in the evolution of landscapes they also represent a serious hazard in many areas of the world despite their importance we estimate that landslide maps cover less than 1 of the slopes in the landmasses and systematic information on the type abundance and distribution of landslides is lacking preparing landslide maps is important to document the extent of landslide phenomena in a region to investigate the distribution types pattern recurrence and statistics of slope failures to determine landslide susceptibility hazard vulnerability and risk and to study the evolution of landscapes dominated by mass wasting processes conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography aided by field surveys these methods are time consuming and resource intensive new and emerging techniques based on satellite airborne and terrestrial remote sensing technologies promise to facilitate the production of landslide maps reducing the time and resources required for their compilation and systematic update in this work we first outline the principles for landslide mapping and we review the conventional methods for the preparation of landslide maps including geomorphological event seasonal and multi temporal inventories next we examine recent and new technologies for landslide mapping considering i the exploitation of very high resolution digital elevation models to analyze surface morphology ii the visual interpretation and semi automatic analysis of different types of satellite images including panchromatic multispectral and synthetic aperture radar images and iii tools that facilitate landslide field mapping next we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological event seasonal and multi temporal inventory maps we conclude by arguing that the new tools will help to improve the quality of landslide maps with positive effects on all derivative products and analyses including erosion studies and landscape modeling susceptibility and hazard assessments and risk evaluations

space time landslide predictive modelling abstract landslides are nearly ubiquitous phenomena and pose severe threats to people properties and the environment in many areas investigators have for long attempted to estimate landslide hazard in an effort to determine where when or how frequently and how large or how destructive landslides are expected to be in an area this information may prove useful to design landslide mitigation strategies and to reduce landslide risk and societal and economic losses in the geomorphology literature most of the attempts at predicting the occurrence of populations of landslides by adopting statistical approaches are based on the empirical observation that landslides occur as a result of multiple interacting conditioning and triggering factors based on this observation and under the assumption that at the spatial and temporal scales of our investigation individual landslides are discrete point events in the landscape we propose a bayesian modelling framework for the prediction of the spatio temporal occurrence of landslides of the slide type caused by weather triggers we build our modelling effort on a log gaussian cox process lgcp by assuming that individual landslides in an area are the result of a point process described by an unknown intensity function the modelling framework has two stochastic components i a poisson component which models the observed random landslide count in each terrain subdivision for a given landslide intensity i e the expected number of landslides per terrain subdivision which may be transformed into a corresponding landslide susceptibility and ii a gaussian component used to account for the spatial distribution of the local environmental conditions that influence landslide occurrence and for the spatio temporal distribution of unobserved latent environmental controls on landslide occurrence we tested our prediction framework in the collazzone area umbria central italy for which a detailed multi temporal landslide inventory covering the period from before 1941 to 2014 is available together with lithological and bedding data we subdivided the 79 km2 area into 889 slope units sus in each su we computed the mean and standard deviation of 16 morphometric covariates derived from a 10 m 10 m digital elevation model for 13 lithological and bedding attitude covariates obtained from a 1 10 000 scale geological map we computed the proportion of each thematic class intersecting the given su we further counted how many of the 3 379 landslides in the multi temporal inventory affect each su and grouped them into six periods we used this complex space time information to prepare five models of increasing complexity our baseline model mod1 carries the spatial information only through the covariates mentioned above it does not include any additional information about the spatial and temporal structure of the data and it is therefore equivalent to the predominantly used landslide susceptibility model in the literature the second model mod2 is analogous but it allows for time interval specific regression constants our next two models are more complex in particular our third model mod3 also accounts for latent spatial dependencies among neighboring sus these are inferred for each of the six time intervals to explain variations in the landslide intensity and susceptibility not explained by the thematic covariates by contrast our fourth model mod4 accounts for the latent temporal dependence separately for each su disregarding neighboring influences ultimately our most complex model mod5 contextually features all these relations it contains the information carried by morphometric and thematic covariates six time interval specific regression constants and it also accounts for the latent temporal effects between consecutive slope instabilities at specific sus as well as the latent spatial effects between adjacent sus we also show that the intensity is strongly related to the aggregated landslide area per su because of this our most complex model largely fulfills the definition of landslide hazard commonly accepted in the literature at least for this study area we quantified the spatial predictive performance of each of the five models using a 10 fold cross validation procedure and the temporal predictive performance using a leave one out cross validation procedure we found that mod5 performed better than the others we then used it to test a novel strategy to classify the model results in terms of both landslide intensity and susceptibility which provides more information than traditional susceptibility zonations for land planning and management hereafter we use the term traditional simply to refer to the majority of modelling procedures in the literature we discuss the advantages and limitations of the new modelling framework and its potential application in other areas making specific and general hazard and geomorphological considerations we also give a perspective on possible developments in landslide prediction modelling and zoning we expect our novel approach to the spatio temporal prediction of landslides to enhance the currently limited ability to evaluate landslide hazard and its temporal and spatial variations we further expect it to lead to better projections of future landslides and to improve our collective understanding of the evolution of complex landscapes dominated by mass wasting processes under multiple geophysical and weather triggers

co seismic thrusting rupture and slip distribution produced by the 2008 mw 7 9 wenchuan earthquake china field investigations reveal that the mw 7 9 wenchuan china earthquake of 12 may 2008 produced a 285 km long surface rupture zone with dominantly thrusting slip accompanied by a right lateral component along the central northern segments of the zone and left lateral component along the southern segment along the longmen shan thrust belt eastern margin of the tibetan plateau the co seismic ruptures mainly occurred along the pre existing yingxiu beichuan guanxian anxian and qingchuan faults which are the main faults of the longmen shan thrust belt the displacements measured in the field are approximately 0 5 6 5 m in the vertical typically 1 3 m accompanied by an average left lateral component of 2 m along the 50 km long southernmost segment of the rupture zone and an average right lateral component of 1 m along the 150 km long central northern segments the maximum thrust slip amount is estimated to be 10 m accompanied by 9 m of shortening across the rupture zone this finding is consistent with estimates based on seismic data the rupture length and maximum vertical displacement are the largest among all intracontinental thrust type earthquakes reported to date our findings demonstrate that i the wenchuan earthquake occurred upon pre existing active faults of the longmen shan thrust belt thereby controlling the spatial distribution of co seismic surface rupture and displacement and the rupture processes of the earthquake ii the long rupture length and large thrusting slip resulted from compressive stress associated with eastward extrusion of the tibet plateau as it accommodates the ongoing penetration of the indian plate into the eurasian plate and iii present day shortening strain upon the eastern margin of the tibetan plateau is mostly released by seismic slip along thrust faults within the longmen shan thrust belt

fault slip analysis along the northern margin of the eastern alps molasse helvetic nappes north and south penninic flysch and the northern calcareous alps fault slip data are analyzed and paleostress tensors computed from 84 stations along the northern margin of the eastern alps between liechtenstein and vienna most fault sets resulted from more than one deformation heterogenous sets are divided into homogenous subsets by cross cutting relationships observed in the field and stress tensors are calculated separately for each subset the deviatoric stress tensors fall into six distinct groups that are regionally consistent in orientation stress ratio and relative age throughout the northern margin of the eastern alps from oldest to youngest the tensor groups are as follows 1 1 subhorizontal e w 3 subvertical thrusting related e w compression this group is only encountered in the south penninic flysch and the northern calcareous alps 2 1 subhorizontal n s 3 subvertical thrusting related n s directed compression 3 1 subhorizontal n s 3 subhorizonal e w strike slip faulting conjugate to n s compression 4 1 subvertical 3 subhorizontal e w e w directed subhorizontal extension 5 1 subhorizontal e w 3 subhorizontal n s strike slip faulting during e w compression and 6 1 subvertical 3 subhorizontal about n s 3 trajectories are oriented perpendicular to the general strike of the eastern alps and parallel topographic gradients the six trensor groups correlate with distinct steps in the cretaceous and the post eocene tectonic evolution of the northern units of the eastern alps 1 1 thrusting related e w compressional structures in the south penninic flysch and the northern calcareous alps are correlated to cretaceous top to w directed thrusting in the south penninic and austroalpine domains 2 2 thrusting related n s compressional structures encompass large scale folds with e w trending axes rare e w oriented thrust branch lines and cut off lines and s dipping ramps in the rhenodanubian flysch tensors reflect the stresses during northward thrusting in the late eocene early miocene 3 3 4 strike slip faults and extensional structures depicting n s compression and e w extension formed during the eastward lateral extrusion of the eastern alps prominent reactivations of strike slip faults during subhorizontal extension in the east and permutation between 1 and 2 reflecting periodic superposition of strike slip and normal faulting in the western eastern alps during overall e w extension suggest a close relationship of both tensor groups deformation resulted in the eastward lateral motion of the northern units of the eastern alps that started during the miocene 4 5 the significance of late miocene e w directed compression reactivating pre existing fractures and faults is presently not well understood we tentatively relate this event to a major change of boundary conditions within the miocene 5 6 the youngest deformation recorded is caused by surface uplift and gravitational collapse of the eastern alps

active fault kinematics and crustal stresses along the ionian margin of southeastern sicily since the late cretaceous onset of plate convergence between africa and europe the malta escarpment has been converted from a mesozoic passive margin into a mega hinge fault system with an additional sinistral strike slip component the modern tectonic stress regime with nw se directed maximum horizontal stresses has been established since late messinian times since the pleistocene sinistral strike slip deformation and contemporaneous normal faulting along the malta escarpment have induced the opening of oblique trending onshore grabens at the eastern margin of the hyblean plateau in this study we focus on the kinematics the controlling state of stress and the temporal variation of the neotectonic to active strike slip and normal fault structures the stress tensor calculations reveals that the widespread map scaled to meso scaled normal fault structures are governed by the long term extensional state of stress during the quaternary this long term stress tensor is predominantly controlled by gravitational induced stresses due to vertical load 1 sv and lateral extension due to the topographic gradient of the malta escarpment 3 sh ne sw in this case the average tectonic stresses 2 sh nw se transmitted by the regional to plate tectonic stress field are significantly smaller than the gravitational induced stresses in contrast the clear localization of conjugate sets of meso scaled strike slip fault structures and shear zones without accompanying normal fault structures give strong indications for episodic seismotectonic strike slip faulting under critical stress conditions in this state tectonically induced maximum horizontal stresses are successively increased by ongoing plate convergence from low level stress magnitudes 1 sv 2 sh nw se up to critical stress magnitudes 1 sh nw se 2 sv which are significantly larger than gravitational stresses at the critical state seismotectonic stress release occurs by active strike slip faulting as recently indicated in mid crustal levels by the moderate 1990 augusta earthquake and re establishes the long term extensional state of stress because the strike slip faults and shear zones in the study area were formed as surface ruptures they additionally give indications of episodic large earthquakes in this region with magnitudes greater than 6 0 as reported by several large earthquakes devastating e and se sicily in historical times

les contraintes phanerozoiques dans la plate forme du saint laurent region de montreal quebec the tectonic evolution of the appalachian platform is still not well understood the montreal area however shows evidence of major fracturing events some of which cut the cretaceous intrusions the history of the different stress events recorded in the platform was studied by the analysis of brittle faults and dykes followed by the calculation by way inversion of tensors of the corresponding stresses the tectonics represented is polyphased and its analysis allows a historical reconstitution of the carbonate and flyschoid platform since the lower paleozoic five tectonic stages are recognized corresponding to the major geodynamic events characteristics of northeast north america i early north south distensional events ii appalachian compression in a west northwest east southeast direction iii terminal appalachian compression oriented north northeast south southwest iv cretaceous north south distension v a cenozoic to recent compression in a northwest southeast direction journal tra

speleothems in gypsum caves and their paleoclimatological significance this article highlights the relationship between speleothems growing inside gypsum caves and the particular climate that existed during their development speleothems in gypsum caves normally consist of calcium carbonate calcite or calcium sulphate gypsum and the abundance of such deposits greatly differs from zone to zone observations carried out over the last 20 years in gypsum caves subjected to very different climates italy spain new mexico northern russia cuba argentina highlight wide variation in their cave deposits in arid or semi arid climates the speleothems are mainly composed of gypsum whilst in temperate humid or tropical regions carbonate formations are largely predominant in polar zones no speleothems develop these mineralogical details could be useful paleoclimatic indicators of climate change the interpretation proposed is based on the fact that in gypsum karst the kind of speleothems deposited is determined by competition between the two principal mechanisms that cause precipitation of calcite and gypsum these mechanisms are completely different calcite speleothem evolution is mainly controlled by co2 diffusion while gypsum deposits develop mostly due to evaporation therefore the prevalence of one kind of speleothem over the other and the relationship between the solution precipitation processes of calcite and gypsum may provide evidence of a specific paleoclimate additionally other non common deposits in gypsum caves like moonmilk cave rafts and dolomite speleothems can be used as markers for the prevalence of long dry periods in humid areas seasonal changes in climate or rainfall trends in some gypsum areas moreover the dating of gypsum speleothems could contribute paleoclimatic data relating to dry periods when calcite speleothems are not deposited in contrast the dating of calcite speleothems in gypsum caves could identify former wet periods in arid zones

quaternary rock uplift rates and their implications for the western flank of the north anatolian fault restraining bend inferences from fluvial terrace ages

strike slip fault bridge fluid pumping mechanism insights from field based palaeostress analysis and numerical modelling abstract we present a finite element study of stress perturbation in evolving compressive and extensional strike slip fault bridges the results are compared with a fracture study of a compressive bridge at st donats uk horizontally interbedded calcareous mudstone and bioclastic calcilutite at st donats have a distinct vertical permeability anisotropy this sedimentary sequence behaves as a set of horizontal aquifers the fluid flow in these aquifers is sensitive to mean stress gradients paleostress analysis of field fracture data verified by finite element modelling indicates a rotation of 1 towards parallelism with boundary faults inside the growing compressive bridge boundary faults and bridge faults recorded numerous fluid flow events the modelled mean stress pattern shows a regional maximum within the bridge and local maxima minima pairs at boundary fault tips finite element modelling of an extensional bridge indicates that 3 rotates towards parallelism with boundary faults the mean stress pattern is similar to the pattern in compressive bridge but with maxima and minima locations interchanged the stress patterns are reestablished by each stress build up preceding the rupturation of the boundary faults throughout the development stages of strike slip fault bridges mean stress gradients developed pre failure control the fluid flow in fractures of the strike slip fault system at and after the end of each stress build up and the fluid flow in boundary faults post failure fracture reactivation and new fracture generation within an evolving bridge is a process consisting of multiple successive events that retain the storage capacity of the bridge rupture and sealing of the main bounding faults is a step wise process that opens and closes fluid conduits between areas with different pressures

focused modern denudation of the longmen shan margin eastern tibetan plateau we use river sediment load data to map the pattern of modern denudation across the longmen shan margin of the tibetan plateau suspended sediment load with corrections of bed load and solute load contributions is used to calculate watershed averaged denudation rates decadal erosion is spatially heterogeneous and seasonally modulated by monsoon flows which account for 80 90 of the sediment load enhanced denudation occurs in a 50 km wide band on the hanging wall of the longmen shan and huya fault zones reaching 0 5 0 8 mm yr these rates are similar to kyr scale rates deduced from cosmogenic 10be and to myr scale rates from low temperature thermochronology the sediment flux derived erosion rates decrease with increasing distance plateauward to less than 0 05 mm yr at a distance 200 km northwest of the foot of the longmen shan the gradient in precipitation across this margin alone cannot explain the one order of magnitude spatial difference in erosion rather the river sediment load data delineates a zone of relatively rapid denudation around active faults that carry the longmen shan in their hanging wall from the similarity of denudation rates measured over myr kyr and decadal time scales we propose that erosion of the longmen shan margin has approached a flux steady state the erosional efflux is balanced by advection of rock toward the longmen margin above the 20 nw dipping ramp of the margin bounding fault our results suggest that high amounts of landslide material mobilized by earthquakes such as the mw 7 9 2008 wenchuan event are gradually removed by rivers smoothing sediment flux over time our results also suggest that caution should be exercised when interpreting young cooling ages as evidence of the initiation of plateau uplift advection of an already high plateau into the belt of higher erosion rate at the longmen shan could also give rise to an abrupt cooling history

kinematic and structural development of the cankiri basin central anatolia turkey a paleostress inversion study three different deformation phases have been recognized in the southern part of the cankiri basin from 1 the major structures and 2 through using paleostress inversion techniques for fault slip data the deformation phases recognized from the paleostress data are correlated with those recognized from the major structures and dated accordingly the first phase occurred in the late paleocene to pre burdigalian and is characterized by an oblique r2 and nne ssw to ne sw trending subhorizontal r1 and wnw ese to nw se trending r3 patterns which indicate transcurrent deformation associated with a combination of thrusting and strike slip faulting transpression possibly due to indentation of the kirsehir block to the sakarya continent the second phase occurred from the burdigalian to the serravallian and is characterized by a subvertical r1 and oblique r2 and r3 which indicate oblique extension associated with normal faulting possibly due to a post orogenic collapse the third deformation phase is characterized by a vertical r2 while the other stresses were horizontal which indicate regional transcurrent tectonics which is correlated with the current transcurrent tectonics controlled by the north anatolian fault zone d 2003 elsevier science b v all rights reserved

on the state of stress in new england as determined from earthquake focal mechanisms assuming only that slip occurs in the direction of resolved shear stress on fault planes we have found a wide range of uniform stress tensors each of which is consistent with ten diverse focal mechanisms for recent moderate size earthquakes in new england and vicinity thus it is possible that the variations in focal mechanisms are due to the occurrence of specific pre existing zones of weakness rather than to inhomogeneous stresses acceptable stresses are broadly consistent with those established for other parts of the eastern united states namely northeast or east northeast directed maximum compression and nearly vertical minimum compression

the use of stress tensor discriminator faults in separating heterogeneous fault slip data with best fit stress inversion methods abstract a widely accepted best fit stress inversion method is applied on synthetic extensional heterogeneous fault slip data generated by two driving andersonian stress tensors having similar stress ratios and 3 axes with different trends in order to examine whether the misfit angle ma minimization criterion can be used for separating heterogeneous fault slip data the examination shows that the resolved best fit stress tensors have 3 axes that tend to the bisector of the 3 axes of the driving stress tensors and stress ratios smaller than those of the latter moreover there is a tendency towards determining radial extension stress regimes although such regimes are rare in the earth s crust more importantly the best fit stress inversion methods that use solely the ma minimization criterion cannot be used for the separation of heterogeneous fault slip data especially when the extensional driving stress tensors have stress ratios smaller than r 0 5 i e as are the favored paleostresses in the earth s crust in contrast the percentage of the stress tensor discriminator faults stdf can be a very useful discriminator tool for the establishment and comparison between two resolved stress tensors as the latter have been determined by a best fit stress inversion method moreover the existence of fault slip data that can been considered as possible stdfs during the recording stage advocate for the heterogeneous origin of the fault slip dataset

paleostress analysis of atlantic crustal extension in the quebec appalachians abstract a paleostress analysis using normal fault slip data and jurassic dike trends has been conducted in the quebec and new england appalachians stress tensor analysis of fault slip by a numerical inversion method has distinguished homogeneous and directionally consistent e w and nw se oriented extensional stress regimes in the quebec appalachians and st lawrence lowlands the directions of extension compare well with the mean direction of extensional stress inferred from the jurassic dolerite dike trend in new england both extensions are interpreted as the result of rift related stress associated with the separation of north america and africa early in the late triassic early jurassic fragmentation of pangea the paleostress field configuration is assumed to be related to the direction of divergent plate motion the n s and ne sw late proterozoic faults that bordered the quebec reentrant and taconian acadian structures of the quebec appalachians appear to have played a significant role in the dis

paleostress inversion of fault slip data using the shear stress solution of means 1989 abstract means 1989 presented a graphical solution for shear and normal stress orientations on any generally oriented plane this solution can be used to solve for paleostress orientations for a population of faults where slip direction and slip sense are known a grid search method is used which tests a range of stress orientations and stress ratios attempting to find the tensor which minimizes the angle between measured and predicted slip directions minimizes resolved normal stresses and maximizes resolved shear stresses comparison with previously published tensor search algorithms indicates that computation speed is increased with no loss of accuracy test analysis of data from the yuli aftershock sequence indicates that this method produces results similar to previously published solutions analysis of geologic faults from the piedmont of south carolina indicates a pre jurassic period of normal faulting and extensional deformation dominated by a northwest trending 3

observation and interpretation of fault activity in the rochefort cave belgium abstract very recent fault movements have left their imprint on the karstic morphology in caves of the belgian ardenne western europe to quantify these movements and to understand their possible causes they have been measured since 1997 in the rochefort cave where this recent geological activity is clearly visible specific extensometers adapted to the underground conditions have been developed to measure very slow fault movements in the rochefort cave the movements correspond to a normal mechanism along n070 e striking faults with a small sinistral strike slip component ten years of measurements at the fontaine bagdad fault which shows the most significant displacement in the order of 0 3 m evidences continuous relative movements of 0 04 mm year and 0 01 mm year in the fault dip and strike direction respectively if the geological displacement has been continuous the total displacement could have occurred since the end of the last glacial period microtectonic analysis from the recent striated faults suggests that the maximal principal horizontal stress is oriented n030 e this direction is similar to that of the post last glacial period compressive stress resulting from the glacial isostatic adjustment in this part of europe but is perpendicular to the direction derived in western europe from earthquake fault plane solutions we provide evidence that the fault movements cannot be caused by gravity due to the surface topography or the vacuum in the cave we propose that these fault slips are an expression of the deformation of the lithosphere due to the compressive strain acting since the end of the last glacial period in the peripheral bulge of the flexure resulting from the unloading of the large ice sheet in fennoscandia

surface ruptures on the transverse xiaoyudong fault a significant segment boundary breached during the 2008 wenchuan earthquake china abstract the 220 km long rupture of the 2008 mw 7 9 wenchuan earthquake breached several km scale geometric discontinuities along strike including the previously un mapped nw trending xiaoyudong fault connecting between the two major ne trending rupture planes on the beichuan and pengguan faults in this paper we present high resolution mapping of the 8 km long surface breaks and sinistral oblique thrusting coseismic slip on the xiaoyudong fault scarp height is the largest at the nw end reaching 3 5 m and decreases southward in steps to less than 0 2 m with an average slip gradient of 6 10 3 at a few tens of meters length scale but up to 50 10 3 locally left lateral offsets co vary with the vertical component the largest sinistral slip vector we observed is 2 2 m geological and geophysical evidence suggests that the xiaoyudong fault is likely a 30 sw dipping lateral ramp that soles into the pengguan fault and at its northwestern end intersects with the beichuan fault where the latter has a step in the fault plane kinematically the xiaoyudong fault functions as a tear and conjugate fault and coincides with significant coseismic slip rake rotations on both the beichuan and pengguan faults similar correlation of fault bends with sharp changes in faulting style occurs at other steps along the wenchuan rupture the xiaoyudong fault may have played a positive role in linking coseismic slip partitioning between parallel reverse fault planes facilitating the growth of a longer and more destructive rupture this highlights the role of tear faults in bridging ruptures between segments such that reverse type ruptures can breach steps wider than anticipated from strike slip fault examples transfer faults are common and perhaps poorly documented features in reverse fault systems and their roles in ruptures may increase the maximum potential earthquake magnitude for fold and thrust belts

carboniferous u pb age of the sebago batholith southwestern maine metamorphic and tectonic implications two phases pink and white granite of the sebago batholith of southwestern maine have been dated by the u pb zircon method identical upper concordia intercepts of both rocks indicate an intrusive age of 325 3 m y for the batholith the lower intercept of the pink phase sample 114 13 m y is inferred to represent episodic lead loss due to the intrusion of the nearby cretaceous pleasant mountain stock the lower intercept of the white phase sample 18 21 m y suggests only modern dilatancy lead loss monazites have ages of 272 m y pink and 282 m y white which are thought to be cooling ages rb sr whole rock data have low initial 87 sr 86 sr ratios of 0 7031 pink and 0 7053 white these data in conjunction with published 40 ar 39 ar rb sr k ar and fission track ages suggest that little or no uplift occurred in this part of new england until the permian and that the uplift rate from 275 m y to 225 m y was 3 times as rapid as was the rate for 225 m y to the present the carboniferous age of the sebago batholith suggests that currently accepted metamorphic and tectonic interpretations for southwestern maine and for east central new hampshire require revision

landslide susceptibility mapping for a part of tectonic kelkit valley eastern black sea region of turkey considering damage to man made structures by natural hazards in turkey landslides are the second most important hazard after earthquakes for this reason a large scale study titled turkish landslide inventory project has been carried out since 1998 during this project some special susceptibility hazard and risk assessments have been performed in this study a landslide susceptibility map of a part of tectonic kelkit valley in the north of central turkey was produced employing binary logistic regression analyses to achieve the most appropriate results some sensitivity analyses were also carried out for this purpose four different data sets were constructed considering conditioning factors used and sampling strategies applied for the training data sets in this study as a consequence of the analyses the most proper outcomes were obtained by using the data set in which continuous topographical parameters and lithological dummy variables were implemented together and 50 of training data set was taken from seed cells at random correct classification percentage and root mean square error rmse values for the validation data for that case were estimated as 84 16 and 0 36 respectively this prediction capability shows that the landslide susceptibility map produced in this research paper can be used for the planning of protective and mitigation measures in the region

an improved method for determining the regional stress tensor using earthquake focal mechanism data application to the san fernando earthquake sequence the orientations of fault planes and slip directions indicated by a population of earthquake focal mechanisms can be used to determine best fit regional principal stress directions and r 2 1 3 1 a measure of relative stress magnitudes under the assumption of uniform stress in the source region this analysis allows for the possibility that failure occurs on preexisting zones of weakness of any orientation in the inversion we perform a grid search of stress models to find the one which requires the smallest total rotation of all the fault planes that is needed to match the observed and predicted slip directions the method allows for errors in orientations of both the fault planes and slip directions we have an objective means for identifying the more likely of the two possible fault planes from each focal mechanism relative to a given stress model thus we do not face the problem of ambiguity of nodal planes which plagues other analyses of this kind by using a grid search of stress models rather than a linearization scheme we are able to perform a realistic error analysis and thus establish confidence limits for the preferred regional stresses the method can be used to investigate possible stress inhomogeneities during earthquake sequences by analyzing subsets of the data population the technique has been applied to 76 events from the san fernando earthquake sequence for which we have found best fit stresses plunge and azimuth 1 7 187 2 27 281 3 62 84 and r 0 65 the average misfit between this stress model and all the data is about 8 and all but eight of the aftershocks have misfits of less than 20 these values are considerably less than the uncertainty of the focal mechanism determinations therefore significant stress inhomogeneities are not required by the data our analysis does not support the suggestion of a change in stresses during the aftershock sequence as proposed by others on the basis of an apparent change in focal mechanisms

major earthquakes recorded by speleothems in midwestern u s caves historic earthquakes generated by the new madrid seismic zone represent some of the largest recorded in the united states yet prehistoric events are recognized only through deformation in late wisconsin to holocene age near surface sediments liquefaction monoclinal folding and changes in river meanders in this article we show that speleothems in caves of southwestern illinois and southeastern missouri may constitute a previously unrecognized recorder of large earthquakes in the u s midcontinent region the timing of the initiation and regrowth of stalagmites in southwestern illinois and southeastern missouri caves is consistent with the historic and prehistoric record of several known seismic events in the u s midcontinent region we conclude that dating the initiation of original stalagmite growth and later postearthquake rejuvenation constitutes a new paleoseismic method that has the potential for being applied to any region around the world in the vicinity of major seismic zones where caves exist use of this technique could expand the geographical distribution of paleoseimic data document prehistoric earthquakes and help improve interpretations of paleoearthquakes

the inverse problem in microtectonics and the separation of tectonic phases abstract the algorithm of inverse problems is applied to three cases in microtectonics a collection of striations measured on pre existing faults may be processed automatically and interpreted in terms of tectonic stress a comparison is made between two different methods formerly proposed by the authors both methods are tested with field data the theoretical results agree with independent field criteria for a separation of tectonic phases

determination of the tectonic stress tensor from slip along faults that obey the coulomb yield condition a new method to calculate the stress tensor associated with slip along a population of faults is derived here the method incorporates two constraints first the stresses in the slip direction satisfy the coulomb yield criterion and second the slip occurs in the direction of maximum shear stress along the fault the computations provide the complete stress tensor normalized by the vertical stress and evaluation of the mean coefficient of friction and the mean cohesion of the faults during the time of faulting the present method is applied to three field cases dixie valley nevada wadi neqarot israel and yuli microearthquakes taiwan it is shown that the coefficieet of friction of the three cases varies between 0 1 to 0 8 further it is demonstrated that previous stress inversion methods implicitly assume zero friction along the faults

tertiary extension development and extension compression interplay in the west carpathian mountain belt abstract this paper describes palaeostresses calculated from fault striae data the inferred palaeostrain patterns and determines the inter relation of the compression and extension during the tertiary development of the west carpathians the calculated stress and inferred strain patterns for the palaeogene burdigalian indicate that the ancestral west carpathians formed a more or less straight orogenic belt this belt underwent contraction and uplift in its narrow frontal zone stretching along its strike during the paleocene chattian and regional contraction and uplift during the chattian burdigalian the strain stress pattern is similar to the collision related pattern known from the eastern alps for the paleocene burdigalian during the burdigalian tortonian the calculated and inferred west carpathian stress and strain patterns indicate narrow frontal contractional and lateral sinistral transpressional zones in the orogenic front and broad extensional and dextral transtensional zones in the orogenic interior the stress strain pattern is similar to the subduction related pattern known from areas such as the hellenic or sunda banda arcs

landslide inventory of northwestern anatolia turkey turkey is heavily exposed to natural hazards such as earthquakes landslides and floods the total loss caused by landslides in terms of affected buildings in a period of 35 years between 1959 and 1994 constitutes 27 of the entire loss from all natural hazards and is second after earthquakes there are no other available data on either direct or indirect losses due to landslides on a national scale the general directorate of mineral research and exploration mta started the turkish landslide inventory mapping project in 1997 to improve understanding of regional and national landslide processes the purpose of the project is to establish landslide inventory maps at medium 1 25 000 regional 1 100 000 and national 1 500 000 scales existing landslides are mapped on 1 25 000 scale topographic base maps by interpretation of aerial photographs and field investigations the base maps are then digitized and stored in a geographic information system gis database by the geological research department of mta hence regional and national scale landslide maps will be available as well as the work progresses landslides are classified as fall topple slide and flow and are broadly characterized as active or inactive the landslides are also classified according to their relative depths as shallow depth 5 m the present paper will attempt to describe the project standards and its application to the area of 1 500 000 scale zonguldak quadrangle the study area extends to 39 081 km2 and 7 1 of the area was found to be affected by landslides a total 10 007 landslides 392 shallow seated 8020 deep seated active and 1595 deep seated inactive were mapped in the area covering 2768 km2 cretaceous flysch paleocene eocene flysch and paleocene middle miocene volcanics are the most landslide prone units and constitute 27 8 29 9 and 7 2 of the all landslides respectively

landslide susceptibility delineation in the ar rayth area jizan kingdom of saudi arabia using analytical hierarchy process frequency ratio and logistic regression models mountain areas in the southern western corner of the kingdom of saudi arabia ksa frequently suffer from various types of landsides induced by rainstorms and anthropogenic activities to mitigate these problems landslide susceptibility mapping and classification is important to develop quick and safe mitigation or remediation measures and to help the decision making in future planning by identifying the most vulnerable areas this paper summarizes the findings of a landslide susceptibility analysis in the ar rayth area jizan ksa using an analytical hierarchy process ahp frequency ratio fr and logistic regression lr models with the aid of gis tools and remote sensing data the landslide inventory map was prepared according to historical data interpretation of high resolution satellite images geo eye 0 5 m resolution and quickbird 0 6 m resolution topographic maps 1 10 000 and verified by field investigations an inventory map with 253 landslides locations was extracted from many sources the landslide inventory was randomly divided into two datasets 75 for training the models and 25 for validation an enhanced thematic mapper plus 15 m satellite image acquired in 2006 was used for determining the normalized difference vegetation index a contour map 1 10 000 with a 10 m contour interval was converted to digital elevation model 10 m resolution and subsequently converted to slope slope aspect curvature elevation and drainage networks geological data obtained with the help of satellite images were used to prepare lithological units and lineaments roads were digitized from the high resolution image and a rainfall map was prepared from the rainfall gauges distributed throughout the study area all these data were used to construct a spatial database using gis and image processing three landslide susceptibility maps were constructed one on the basis of a heuristic method using an ahp the other two on the basis of landslide inventories and causative factors using fr and lr furthermore each causative factor s weight was determined according to these three models and landslide susceptibility indices were calculated for verification receiver operating characteristic curves were calculated and the areas under the curve auc for success rate are 0 755 0 828 and 0 749 and for prediction rate are 0 708 0 781 and 0 727 for the ahp fr and lr respectively in addition the percentage of existing training landslides data in high and very high zones of the susceptibility maps is of 73 2 85 31 and 88 59 and for the validation landslides data is 73 2 85 31 and 88 59 for the ahp fr and lr respectively the findings indicated that the values of auc are above 0 7 for both success and prediction rate which indicate these three models are suitable for susceptibility analysis also percent of training and validation landslides data of high and very high zones indicate that lr model is more accurate followed by fr model and ahp model

tectonic analysis of fault slip data sets using data that include the direction and the sense of motion on individual fault surfaces determined by slickenside lineations it is possible to reconstruct reduced stress tensors that correspond to the orientation of stress axes and to the ratio 2 3 1 3 between principal stress values 1 2 3 compression being positive no assumption is made concerning the orientation of fault planes relative to stress axes so that reactived faults are taken into account as well as newly created ones qualitative and quantitative methods for analysis of fault slip data were developed during the last 10 years the practical limitation of the methods and the necessity for critical field observations are emphasized these methods can be applied to focal mechanisms of earthquakes a more complex analysis of heterogeneous data sets involving an iterative separation of different stress systems is also discussed this analysis enables one to distinguish successive faulting events careful qualitative study in the field is in all cases essential

landslide susceptibility mapping for ayvalik western turkey and its vicinity by multicriteria decision analysis this paper presents the results of geographical information system gis based landslide susceptibility mapping in ayvalik western turkey using multi criteria decision analysis the methodology followed in the study includes data production standardization and analysis stages a landslide inventory of the study area was compiled from aerial photographs satellite image interpretations and detailed field surveys in total 45 landslides were recorded and mapped the areal extent of the landslides is 1 75 km2 the identified landslides are mostly shallow seated and generally exhibit progressive character they are mainly classified as rotational planar and toppling failures in all 51 45 and 4 of the landslides mapped are rotational planar and toppling types respectively morphological geological and land use data were produced using existing topographical and relevant thematic maps in a gis framework the considered landslide conditioning parameters were slope gradient slope aspect lithology weathering state of the rocks stream power index topographical wetness index distance from drainage lineament density and land cover and vegetation density these landslide parameters were standardized in a common data scale by fuzzy membership functions then the degree to which each parameter contributed to landslides was determined using the analytical hierarchy process method and the weight values of these parameters were calculated the weight values obtained were assigned to the corresponding parameters and then the weighted parameters were combined to produce a landslide susceptibility map the results obtained from the susceptibility map were evaluated with the landslide location data to assess the reliability of the map based on the findings obtained in this study it was found that 5 19 of the total area was prone to landsliding due to the existence of highly and completely weathered lithologic units and due to the adverse effects of topography and improper land use

palaeostress inversion in a multiphase deformed area kinematic and structural evolution of the cankiri basin central turkey part 1 northern area the kinematic and structural evolution of the major structures affecting the cankiri basin central turkey has been deduced from a palaeostress inversion study four palaeostress tensor configurations indicative of four phase structural evolution have been constructed from the fault slip data collected from the cankiri basin the first two phases indicate the dominant role of thrusting and folding and are attributed to the collision between the pontides and the taurides the proposed interface of which is straddled by the cankiri basin phase 1 occurred in the pre late palaeocene and phase 2 in the late palaeocene pre burdigalian the third phase is dominated by extensional deformation in the middle miocene the latest phase has been active since then and is characterized by regional transcurrent tectonics

assessment of geo environmental problems of the zonguldak province nw turkey the zonguldak province is a coastal settlement area that has been suffering from serious natural and human induced environmental problems sourced by its geology and geomorphology since the province locates at the heart of a coal producing basin the geo environmental problems related to mining activities such as esthetic degradation disposal of mining wastes and subsidence of the abandoned coal galleries are badly affecting every day life in zonguldak province disposal of municipal wastes is also a big problem since only one municipality out of 32 has a sanitary disposal area the rest of the municipalities dispose their solid wastes to rivers or to the sea the province has also some health problems which are pointed out in the literature related to coal mining and geologic environment these are cytogenetic damage in peripheral lymphocytes and pheumoconiosis most commonly seen at coal workers goiter and cancer landslides are the most important hazards in the area since 13 of the total surface of the zonguldak is affected by landslides in this study considering the hazard potential special attention is given to deep landslides and using the stepwise forward conditional logistic regression technique the landslide susceptibility map for the zonguldak province is produced the results showed that the most important independent variables governing the landslides are slope gradient volcanic and sedimentary rocks of eocene and clastic and carbonate units of cretaceous the landslide map is used as a base map for the production of geo hazard reconnaissance map on which areas subjected to other important geo hazards flood earthquake and subsidence are also shown to provide guidance for both existing settlement areas to take the necessary preventive measures and for new developing settlement areas to avoid the problematic areas

earthquake related speleothem damages observations from the 2008 mw 7 9 wenchuan china abstract a speleoseismological study has been conducted at over a dozen cave sites along the longmen shan fault zone of the eastern qinghai tibet plateau the aim was to assess the damage inflicted on speleothems by the mw 7 9 wenchuan earthquake results show that the earthquake led to either partial or complete collapse of the caves soda straws are shown to be particularly vulnerable to earthquake damage but statistical analyses indicate that the spindle and slender shapes are also very likely to break cave depth is also shown to play an important role in the fracture development during the earthquake the measured orientations of fallen stalactites are preferentially aligned to the coseismic surface offset peaks and therefore to the direction of earthquake wave propagation several such damaged speleothems resulting from sudden co seismic movements were observed the direction of ceiling hanging wall movement caused by the wenchuan earthquake is nw nnw consistent with block motion on the footwall of the yingxiu beichuan fault we inferred that the faults in the caves were not co seismic structures of the wenchuan earthquake but instead they are likely normal faults as the result of gravity creeping induced by the earthquake

application of logistic regression for landslide susceptibility zoning of cekmece area istanbul turkey as a result of industrialization throughout the world cities have been growing rapidly for the last century one typical example of these growing cities is istanbul the population of which is over 10 million due to rapid urbanization new areas suitable for settlement and engineering structures are necessary the cekmece area located west of the istanbul metropolitan area is studied because the landslide activity is extensive in this area the purpose of this study is to develop a model that can be used to characterize landslide susceptibility in map form using logistic regression analysis of an extensive landslide database a database of landslide activity was constructed using both aerial photography and field studies about 19 2 of the selected study area is covered by deep seated landslides the landslides that occur in the area are primarily located in sandstones with interbedded permeable and impermeable layers such as claystone siltstone and mudstone about 31 95 of the total landslide area is located at this unit to apply logistic regression analyses a data matrix including 37 variables was constructed the variables used in the forwards stepwise analyses are different measures of slope aspect elevation stream power index spi plan curvature profile curvature geology geomorphology and relative permeability of lithological units a total of 25 variables were identified as exerting strong influence on landslide occurrence and included by the logistic regression equation wald statistics values indicate that lithology spi and slope are more important than the other parameters in the equation beta coefficients of the 25 variables included the logistic regression equation provide a model for landslide susceptibility in the cekmece area this model is used to generate a landslide susceptibility map that correctly classified 83 8 of the landslide prone areas

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

producing a landslide inventory map using pixel based and object oriented approaches optimized by taguchi method abstract landslides are considered one of the most important natural hazards mapping landslides and producing landslide inventory maps have received special attention from a wide range of specialists the main objective of this study was to produce landslide inventory maps using advanced pixel based ann and svm and object oriented approaches the most important challenge in this case is to determine the optimum structure of classification methods the taguchi method was to perform optimization of the structure of ann and svm and segmentation process in the object oriented classification method results showed that the taguchi method can be effectively used to cope with this problem it significantly reduces the number of classification tests we also showed that there were no significant differences existed between ann and svm approaches 2 value of 3 33 however we demonstrated that object oriented approaches significantly outperformed the pixel based classification methods z value of 5 70 in producing a landslide inventory map the accurate map produced using an object oriented approach overall accuracy of 0 90 effectively determines the shape of landslides and also efficiently shows the intensifying effects of land use changes in the occurrence of landslides

keys and pitfalls in mesoscale fault analysis and paleostress reconstructions the use of angelier s methods whereas most of the stress inversion methods using fault slip data only minimize the angle between the measured striation and a computed shear stress to find the best fitting reduced stress tensor angelier 1990 proposed an alternative method named invd that also takes into account the relative shear stress magnitude which allows the fault to move using artificial datasets and particular fault geometries we compare this method with one of the classical methods based on the minimization of the shear slip angles r4dt angelier 1984 and we show that in most cases the new method has improved the quality of the results furthermore as proposed by angelier we point out that the quality of the stress inversion primarily depends on the quality of the field data we give advice and warn about some pitfalls concerning determination of sense of slip on fault planes recognition of successive faulting events and their chronology drawer or wedge faults stress permutations faults in vertical bedding we also argue that in case of tilted sequences fault diagrams should not be presented without bedding planes but we show that stress inversions when realized with caution and with the correct method can havemuch more applications than reconstructing stress fields like for determining the paleo horizontal the nature and the sense of motion of large faults the chronology and age of large structures

kinematic and thermal evolution of the haymana basin a fore arc to foreland basin in central anatolia turkey abstract gondwana tauride kirsehir blocks and eurasia pontides derived continental blocks delimit the haymana basin central turkey to the south and the north respectively the boundaries of these blocks define the izmir ankara erzincan and intra tauride suture zones which are straddled by a number of late cretaceous to oligocene marine to continental basins the haymana basin is located at the junction of the iaesz and itsz and comprises upper cretaceous to middle eocene basin infill deposited in response to the interaction of these blocks the basin provides a unique opportunity to unravel spatio temporal relationships related to the timing of late stage subduction history of neo tethys ocean and subsequent collision of the intervening continental blocks we have conducted a multidisciplinary study in the region that includes mapping of major structures combined with fault kinematic analyses e w striking folds dominate the basin cross section balancing of these structures indicates around 25 roughly n s shortening in the region paleostress studies indicate that the basin was initially subjected to n s to nne ssw extension until the middle paleocene phase 1 and then n s directed syn depositional compression and coeval e w directed extension until the middle miocene phase 2 implying strike slip deformation and pure shear shortening in the basin these different deformation phases are attributed to first fore arc subduction basin development then foreland collision stages of the basin apatite u th he dating of 5 samples indicate that exhumation of the se segment of the basin started in early oligocene whereas the nw segment of the basin exhumed in the early miocene the differential uplift is possibly related to progressive north westwards movement of derekoy basin bounding fault at the north we propose that the haymana basin evolved from extensional forearc basin during the late cretaceous to early paleocene and foreland basin after the terminal subduction and subsequent collision of tauride and pontide blocks

a plea for more caution in fault slip analysis abstract the analysis of fault slip data is a widely used tool in structural geology this method consists of three major steps a data acquisition by measurements in outcrops b data separation into homogeneous subsets and calculation of the principal stress or strain axes with one of several available methods and c data interpretation in a regional tectonic context which includes the assignment of ages and the derivation of regional patterns each one of these three steps may introduce artefacts and misinterpretations the major problem during step a is sampling bias due to unfavourable outcrop geometry or due to neglecting faults with subtle slip sense indicators step b contains numerous possibilities to influence the calculation results e g by arbitrary separation of data into subsets choice of the analysis method and uncritical use of software age assignment in step c can in most cases be made only indirectly e g by the assumption that measured outcrop scale faults have the same age as parallel map scale faults or by the inference that subsets from different sites with parallel oriented principal axes are syngenetic neither assumption is necessarily valid with this paper we want to sharpen researchers awareness of the problems related to fault slip analysis

landslide susceptibility mapping for a landslide prone area findikli ne of turkey by likelihood frequency ratio and weighted linear combination models landslides are very common natural problems in the black sea region of turkey due to the steep topography improper use of land cover and adverse climatic conditions for landslides in the western part of region many studies have been carried out especially in the last decade for landslide susceptibility mapping using different evaluation methods such as deterministic approach landslide distribution qualitative statistical and distribution free analyses the purpose of this study is to produce landslide susceptibility maps of a landslide prone area findikli district rize located at the eastern part of the black sea region of turkey by likelihood frequency ratio lrm model and weighted linear combination wlc model and to compare the results obtained for this purpose landslide inventory map of the area were prepared for the years of 1983 and 1995 by detailed field surveys and aerial photography studies slope angle slope aspect lithology distance from drainage lines distance from roads and the land cover of the study area are considered as the landslide conditioning parameters the differences between the susceptibility maps derived by the lrm and the wlc models are relatively minor when broad based classifications are taken into account however the wlc map showed more details but the other map produced by lrm model produced weak results the reason for this result is considered to be the fact that the majority of pixels in the lrm map have high values than the wlc derived susceptibility map in order to validate the two susceptibility maps both of them were compared with the landslide inventory map although the landslides do not exist in the very high susceptibility class of the both maps 79 of the landslides fall into the high and very high susceptibility zones of the wlc map while this is 49 for the lrm map this shows that the wlc model exhibited higher performance than the lrm model