a procedure for landslide susceptibility zonation by the conditional analysis method numerous methods have been proposed for landslide probability zonation of the landscape by means of a geographic information system gis among the multivariate methods i e those methods which simultaneously take into account all the factors contributing to instability the conditional analysis method applied to a subdivision of the territory into unique condition units is particularly straightforward from a conceptual point of view and particularly suited to the use of a gis in fact working on the principle that future landslides are more likely to occur under those conditions which led to past instability landslide susceptibility is defined by computing the landslide density in correspondence with different combinations of instability factors the conceptual simplicity of this method however does not necessarily imply that it is simple to implement especially as it requires rather complex operations and a high number of gis commands moreover there is the possibility that in order to achieve satisfactory results the procedure has to be repeated a few times changing the factors or modifying the class subdivision to solve this problem we created a shell program which by combining the shell commands the gis geographical research analysis support system grass commands and the gawk language commands carries out the whole procedure automatically this makes the construction of a landslide susceptibility map easy and fast for large areas too and even when a high spatial resolution is adopted as shown by application of the procedure to the parma river basin in the italian northern apennines

equatorial undercurrents associated with indian ocean dipole events during contrasting summer monsoons 1 positive indian ocean dipole iod events generally tend to be accompanied by intensified summer monsoon flows and above normal precipitation over the sub continent although strong monsoons have not always coincided with positive iod events numerical simulation experiments and supplementary data diagnostics are performed to understand the iod sub surface dynamics in relation to the monsoon strength the model experiments when forced by iod winds during strong monsoon periods generated a strong subsurface zonal pressure gradient along the equator and an eastward equatorial undercurrent euc leading to supply of cold subsurface waters to the upwelling regions in the eastern equatorial indian ocean however the simulations when forced with iod winds during weak monsoon periods were unable to set up the subsurface pressure gradients and the euc thus resulting in weak sst cooling in the east these results raise the possibility that iod monsoon interactions during strong monsoon years might favor intensification of the iod

a country wide spatial assessment of landslide susceptibility in romania abstract this paper proposes a brief spatial analysis of landslides in romania completed by a landslide susceptibility model landslides constitute a very common geomorphic hazard in this country mainly in the hilly regions which occupy around 30 of romania s territory the landslide susceptibility assessment at national level was accomplished using a landslide susceptibility index lsi computed in gis which considers and weights the main factors that control landslide activity lithology slope gradient maximum rainfall in 24 h land use seismicity and local relief each factor was classified into 7 18 classes which were rated from 1 to 10 by means of expert judgement a formula was devised to compute the landslide susceptibility index over each 100 m 100 m pixel and the resulting values were ranked into 5 landslide susceptibility classes this synthetic method of landslide susceptibility assessment applied to the whole country is a useful tool to evaluate the distribution of landslide prone areas as well as to validate and to enhance some results obtained in previous studies based on field research and map interpretation the most landslide prone areas correspond to the subcarpathians an outer fringe of hilly terrain accompanying the carpathians as well as to the moldavian plateau in the east the semi quantitative approach has been validated with satisfactory results in a particular sector using independent cartographic landslide inventories

gis based evaluation of diagnostic areas in landslide susceptibility analysis of bahluieț river basin moldavian plateau ne romania are neolithic sites in danger abstract the aim of this study is to compare the predictive strenghtness of different diagnostic areas in determining landslide susceptibility using frequency ratio fr statistical index si and analytic hierarchy process ahp models in a catchment from the northeastern part of romania scarps point landslide areas polygon and middle of the landslide point have been tested and checked in regards to their performance the three statistical models have been employed to assess the landslide susceptibility using eleven conditioning factors slope angle elevation curvature lithology precipitations land use topographic wetness index twi landforms aspect plan curvature and distance to river the three models were validated using the receiver operating characteristic roc curves and the seed cell area index scai methods the predictive capability of each model was established from the area under the curve auc for fr si and ahp the values are 0 75 0 81 and 0 78 using polygon as diagnostic area respectively among the three methods used si had a better predictability when it comes to the predictability values regarding the diagnostic areas the landslide area polygon proves to have the highest values this results from the entire surface of the landslide being taken into account when validating the data approximately 70 of the neolithic sites are located in areas with high and very high susceptibility to landslides meaning that they are in danger of being destroyed in the future the final susceptibility maps are useful in hazard mitigation risk reduction a sustainable land use planning evaluation of cultural heritage integrity and to highlight the most endangered sites that are likely to be destroyed in the future

linking landslide susceptibility to sediment yield at regional scale application to romania abstract it is generally accepted that catchment sediment yield sy t km 2 y 1 can be strongly influenced by landsliding nevertheless due to data requirements only few studies investigated this effect at a regional scale the objective of this study is therefore to explore the potential of a landslide susceptibility map for explaining the spatial variation of sy in romania we selected 133 catchments in romania for which sy was measured during a period of at least 10 years for each catchment we derived a variety of proxies that potentially explain sy including several indicators of landslide occurrence the latter were derived from a published landslide susceptibility map results show that sy is significantly correlated with mean landslide susceptibility r 2 0 30 estimates of average sheet and rill erosion rates showed a much weaker correlation with sy r 2 0 06 further analyses showed that the strong correlation between sy and landslide susceptibility is mainly attributed to regional variations in lithology and seismicity especially the latter may play a crucial role in understanding denudation rates at regional scales e g by facilitating the occurrence of landslides using landslide proxies that also account for sediment connectivity did not result in stronger correlations overall our results show that landslide susceptibility maps can be a highly useful tool to predict sy at regional scales provided that they incorporate all relevant factors

understanding the origins of interannual thermocline variations in the tropical indian ocean 1 based on the data analysis of the 1000 hpa wind sst and ssh anomalies it is revealed that the atmospheric variations associated with indian ocean dipole iod or referred as indian ocean zonal dipole mode iozdm consist of a pair of anticyclones closely north and south of the equator with accompanying intense equatorial easterly anomalies while the atmospheric variations related to el nino southern oscillation enso include a strong anticyclone in the southeastern tropical indian ocean tio at higher latitudes with strong along shore wind anomalies near java sumatra coast the different atmospheric forcing patterns lead to the fact that oceanic thermocline variations associated with iod iozdm are more closely confined to the region north of 10 s while enso induced thermocline variations are dominant south of 10 s

climate physiographically differentiated pan european landslide susceptibility assessment using spatial multi criteria evaluation and transnational landslide information abstract with the adoption of the eu thematic strategy for soil protection in 2006 small scale 1 1 m assessments of threats affecting soils over europe received increasing attention as landslides have been recognized as one of eight threats requiring a pan european evaluation we present an approach for landslide susceptibility evaluation at the continental scale over europe unlike previous continental and global scale landslide susceptibility studies not utilizing spatial information on the events we collected more than 102 000 landslide locations in 22 european countries these landslides are heterogeneously distributed over europe but are indispensable for the evaluation and classification of pan european datasets used as spatial predictors and the validation of the resulting assessments for the analysis we subdivided the european territory into seven different climate physiographical zones by combining morphometric and climatic data for terrain differentiation and adding a coastal zone defined as a 1 km strip inland from the coastline landslide susceptibility modeling was performed for each zone using heuristic spatial multicriteria evaluations supported by analytical hierarchy processes and validated with the inventory data using the receiver operating characteristics in contrast to purely data driven statistical modeling techniques our semi quantitative approach is capable to introduce expert knowledge into the analysis which is indispensable considering quality and resolution of the input data and incompleteness and bias in the inventory information the reliability of the resulting susceptibility map elsus 1000 version 1 1 km resolution was examined on an administrative terrain unit level in areas with landslide information and through the comparison with available national susceptibility zonations these evaluations suggest that although the elsus 1000 is capable for a correct synoptic prediction of landslide susceptibility in the majority of the area it needs further improvement in terms of data used

the assessment of landslide susceptibility mapping using random forest and decision tree methods in the three gorges reservoir area china landslide susceptibility mapping is an indispensable prerequisite for landslide prevention and reduction at present research into landslide susceptibility mapping has begun to combine machine learning with remote sensing and geographic information system gis techniques the random forest model is a new integrated classification method but its application to landslide susceptibility mapping remains limited landslides represent a serious threat to the lives and property of people living in the zigui badong area in the three gorges region of china as well as to the operation of the three gorges reservoir however the geological structure of this region is complex involving steep mountains and deep valleys the purpose of the current study is to produce a landslide susceptibility map of the zigui badong area using a random forest model multisource data gis and remote sensing data in total 300 pre existing landslide locations were obtained from a landslide inventory map these landslides were identified using visual interpretation of high resolution remote sensing images topographic and geologic data and extensive field surveys the occurrence of landslides is closely related to a series of environmental parameters topographic geologic landsat 8 image raining data and seismic data were used as the primary data sources to extract the geo environmental factors influencing landslides thirty four layers of causative factors were prepared as predictor variables which can mainly be categorized as topographic geological hydrological land cover and environmental trigger parameters the random forest method is an ensemble classification technique that extends diversity among the classification trees by resampling the data with replacement and randomly changing the predictive variable sets during the different tree induction processes a random forest model was adopted to calculate the quantitative relationships between the landslide conditioning factors and the landslide inventory map and then generate a landslide susceptibility map the analytical results were compared with known landslide locations in terms of area under the receiver operating characteristic curve the random forest model has an area ratio of 86 10 in contrast to the random forest whole factors wf random forest 12 major factors 12f decision tree wf decision tree 12f the final result shows that random forest 12f has a higher prediction accuracy meanwhile the random forest models have higher prediction accuracy than the decision tree model subsequently the landslide susceptibility map was classified into five classes very low low moderate high and very high the results demonstrate that the random forest model achieved a reasonable accuracy in landslide susceptibility mapping the landslide hazard zone information will be useful for general development planning and landslide risk management

subsurface equatorial zonal current in the eastern indian ocean 1 variations of subsurface zonal current in the eastern equatorial indian ocean are investigated by examining 6 year data december 2000 november 2006 from acoustic doppler current profiler adcp mooring at 0 s 90 e the analysis indicates the presence of an eastward equatorial subsurface current between 90 and 170 m depths during both boreal winter and summer during boreal winter the generation of eastward pressure gradient which drives an eastward flow in the thermocline is caused primarily by upwelling equatorial kelvin waves excited by prevailing easterly winds on the other hand the downwelling rossby waves generated by the reflection of the spring downwelling kelvin waves in the eastern boundary as well as the upwelling equatorial kelvin waves triggered by easterlies create an oceanic state that favors the generation of the eastward pressure gradient during boreal summer the subsurface current reveals a distinct seasonal asymmetry the maximum eastward speed of 63 cm s 1 is observed in april and secondary maximum of 49 cm s 1 is seen in october the zonal transport per unit width within depth of the subsurface current exhibits similar variations reaching maximum eastward transport of 35 m2 s 1 in april and secondary maximum of 29 m2 s 1 in october moreover the subsurface current during boreal summer undergoes significant interannual variations it was absent in 2003 but it was anomalously strong during 2006

intraseasonal variability of the equatorial undercurrent in the indian ocean by analyzing in situ observations and conducting a series of ocean general circulation model experiments this study investigates the physical processes controlling intraseasonal variability isv of the equatorial undercurrent euc of the indian ocean isv of the euc leads to time varying water exchanges between the western and eastern equatorial indian ocean for the 2001 14 period standard deviations of the euc transport variability are 1 92 and 1 77 sv 1 sv 10 6 m 3 s 1 in the eastern and western basins respectively the isv of the euc is predominantly caused by the wind forcing effect of atmospheric intraseasonal oscillations isos but through dramatically different ocean dynamical processes in the eastern and western basins the stronger isv in the eastern basin is dominated by the reflected rossby waves associated with intraseasonal equatorial zonal wind forcing it takes 20 30 days to set up an intraseasonal euc anomaly through the kelvin and rossby waves associated with the first and second baroclinic modes in the western basin the peak intraseasonal euc anomaly is generated by the zonal pressure gradient force which is set up by radiating equatorial kelvin and rossby waves induced by the equatorial wind stress directly forced and reflected rossby waves from the eastern basin propagate westward contributing to intraseasonal zonal current near the surface but having weak impact on the peak isv of the euc

impacts of the iod associated temperature and salinity anomalies on the intermittent equatorial undercurrent anomalies the study of equatorial undercurrent euc has attracted a broad attention in recent years due to its strong response and feedback to the indian ocean dipole in this paper we first produce a high quality simulation of three dimensional temperature salinity and zonal current simulation from 1982 to 2014 using a high resolution ocean general circulation model on this basis with two sensitivity experiments we investigate the role of temperature and salinity anomalies in driving and enhancing the euc during the positive iod events by examining the variation of the euc seasonal cycle and diagnosing the zonal momentum budget along the equatorial indian ocean our results show that during january march the euc can appear along the entire equatorial indian ocean in all years but during august november the euc can appear and reach the eastern indian ocean only during the positive iod events the zonal momentum budget analysis indicates that the pressure gradient force contributes most to the variation of the eastward acceleration of zonal currents in the subsurface during the positive iod events strong negative subsurface temperature anomalies exist in the eastern indian ocean with negative surface salinity anomalies in the central and eastern indian ocean resulting in a large pressure gradient force to drive euc during the august november further the results of two sensitivity experiments indicate that the temperature anomalies significantly impact the pressure gradient force playing a leading role in driving the euc while the surface salinity anomalies can secondarily help to intensify the eastward euc through increasing the zonal density gradient in the eastern indian ocean and impacting the vertical momentum advection in the subsurface

observed interannual variability of zonal currents in the equatorial indian ocean thermocline and their relation to indian ocean dipole interannual variability of zonal currents in the eastern equatorial indian ocean thermocline is significantly correlated with sea surface temperature sst in the eastern pole of the indian ocean dipole iod this relationship is more significant than for zonal currents and the dipole mode index the latter of which measures zonal sst anomaly gradient the variability of zonal currents in the thermocline is consistent with the variations of eastward pressure gradient force in the thermocline and the equatorward geostrophic thermocline flows associated with the shallow meridional overturning circulations in the eastern tropical indian ocean our analysis suggests a positive feedback between zonal currents in the thermocline and sst in the eastern pole of iod the combination of equatorial wind and off equatorial wind stress curls associated with sst anomalies in the eastern pole of the iod drives interannual variability in equatorial zonal thermocline flows and its covariability with the shallow meridional overturning cells

observations of warm water volume changes in the equatorial pacific and their relationship to el nino and la nina abstract this paper describes observed changes in surface winds sea surface temperature sst and the volume of water warmer than 20 c wwv in the equatorial pacific ocean for the period 1980 99 the purpose is to test recent hypotheses about the relationship between variations in wwv and the el nino southern oscillation enso cycle the results confirm inferences based on theory models and previous empirical analyses using proxy data namely sea level that enso involves a recharge and discharge of wwv along the equator and that the cyclic nature of enso results from a disequilibrium between zonal winds and zonal mean thermocline depth the authors also find that the magnitude of enso sst anomalies is directly related to the magnitude of zonal mean wwv anomalies furthermore for a given change in equatorial wwv the corresponding warm el nino sst anomalies are larger than the corresponding cold la nina anomalies this asymmetry between the warm and cold phases of the enso cycle implies differences

volume transports of the wyrtki jets and their relationship to the indian ocean dipole the equatorial indian ocean is characterized by strong eastward flows in the upper 80 100 m during boreal spring and fall referred to as the wyrtki jets these jets are driven by westerly winds during the transition seasons between the southwest and northeast monsoons and represent a major conduit for mass and heat transfer between the eastern and western sides of the basin since their discovery over 40 years ago there have been very few estimates from direct observations of the volume transports associated with these currents in this paper we describe seasonal to interannual time scale variations in volume transports based on 5 years of unique measurements from an array of acoustic doppler current profilers in the central equatorial indian ocean the array was centered at 0 80 5 e and spanned latitudes between 2 5 n and 4 s from august 2008 to december 2013 analysis of these data indicates that the spring jet peaks in may at 14 9 2 9 sv and the fall jet peaks in november at 19 7 2 4 sv around which there are year to year transport variations of 5 10 sv the relationship of the interannual transport variations to zonal wind stress forcing sea surface temperature sea surface height and surface current variations associated with the indian ocean dipole iod are further highlighted we also illustrate the role of wind forced equatorial waves in affecting transport variations of the fall wyrtki jet during the peak season of the iod

assessment of landslide triggering factors and occurrence using morphometric parameters in geyraz basin tokat northern turkey the geyraz stream is one of the tributaries of the yesilirmak river located within the southern of middle black sea section and enters the main river at tokat city centre geyraz is a basin that has experienced numerous landslide events in this study morphometric parameters of areas prone to landslide occurrence were investigated and computed in gis these parameters included the dissection index hypsometric integral drainage density stream power index and compound topographic index first and second orders in addition rocks slopes and frequencies of first and second order streams in subbasins were considered and their correlations were examined the moderate 15 20 and high slope 20 25 values with primarily clayey rocks schist and flysch correspond to high di and hi values a maximum number of first and second order streams and high landslide occurrence while very steep slopes lead to low di values and a low density of landslides results show that former landslides occurred in areas with di values of 0 1 0 15 moderately steep and steep slopes a maximum number of first and second order streams high stream frequency on clayey rocks schist and flysch cti values of 60 100 and spi values of 75 85 in other words landslide events are triggered by higher drainage frequency on primarily clayey rocks intense fluvial incision and medium high steep slopes the location of agricultural land in the landslide area reflecting lack of vegetation cover is another landslide triggering factor thus the study area was ranked in six different classes and risk was rated as very low low medium medium to high high and very high determination of areas prone to landslide occurrence and their triggering factors is important for regional planning with respect to basin management and hazard prevention

landslide susceptibility assessment by bivariate methods at large scales application to a complex mountainous environment statistical assessment of landslide susceptibility has become a major topic of research in the last decade most progress has been accomplished on producing susceptibility maps at meso scales 1 50 000 1 25 000 at 1 10 000 scale which is the scale of production of most regulatory landslide hazard and risk maps in europe few tests on the performance of these methods have been performed this paper presents a procedure to identify the best variables for landslide susceptibility assessment through a bivariate technique weights of evidence woe and discusses the best way to minimize conditional independence ci between the predictive variables indeed violating ci can severely bias the simulated maps by over or under estimating landslide probabilities the proposed strategy includes four steps i identification of the best response variable rv to represent landslide events ii identification of the best combination of predictive variables pvs and neo predictive variables npvs to increase the performance of the statistical model iii evaluation of the performance of the simulations by appropriate tests and iv evaluation of the statistical model by expert judgment the study site is the north facing hillslope of the barcelonnette basin france affected by several types of landslides and characterized by a complex morphology results indicate that bivariate methods are powerful to assess landslide susceptibility at 1 10 000 scale however the method is limited from a geomorphological viewpoint when rvs and pvs are complex or poorly informative it is demonstrated that expert knowledge has still to be introduced in statistical models to produce reliable landslide susceptibility maps

landslide hazard evaluation a review of current techniques and their application in a multi scale study central italy in recent years growing population and expansion of settlements and life lines over hazardous areas have largely increased the impact of natural disasters both in industrialized and developing countries third world countries have difficulty meeting the high costs of controlling natural hazards through major engineering works and rational land use planning industrialized societies are increasingly reluctant to invest money in structural measures that can reduce natural risks hence the new issue is to implement warning systems and land utilization regulations aimed at minimizing the loss of lives and property without investing in long term costly projects of ground stabilization government and research institutions worldwide have long attempted to assess landslide hazard and risks and to portray its spatial distribution in maps several different methods for assessing landslide hazard were proposed or implemented the reliability of these maps and the criteria behind these hazard evaluations are ill formalized or poorly documented geomorphological information remains largely descriptive and subjective it is hence somewhat unsuitable to engineers policy makers or developers when planning land resources and mitigating the effects of geological hazards in the umbria and marche regions of central italy attempts at testing the proficiency and limitations of multivariate statistical techniques and of different methodologies for dividing the territory into suitable areas for landslide hazard assessment have been completed or are in progress at various scales these experiments showed that despite the operational and conceptual limitations landslide hazard assessment may indeed constitute a suitable cost effective aid to land use planning within this framework engineering geomorphology may play a renewed role in assessing areas at high landslide hazard and helping mitigate the associated risk

anomalous surface currents in the tropical indian ocean an anomalous climate event occurred in 1997 in the indian ocean with severe consequences for the surrounding continental areas in response to an intensification of the trade winds a westward gradient of sst and an anomalous reversal of the eastward surface currents with peak velocity anomalies exceeding 1 m s were evident in boreal autumn a similar but weaker event took place in 1994 in this study we examine the observational record during the 1990s including surface drifter velocities sst and altimeter sea level to confirm these dramatic changes we examine the key momentum balance between wind induced momentum flux and the pressure gradient force as well as the important role of horizontal temperature advection in the mixed layer heat response

national level landslide susceptibility assessment of turkey utilizing public domain dataset landslide studies have been integrated into geographic information systems with the help of technological developments using several methods like inventory heuristic statistic and deterministic methods in the recent years however since a nationwide landslide susceptibility zoning map has not been produced for the entire territory of turkey this study aims to produce a landslide susceptibility map of turkey at a national scale by utilizing publicly available datasets in order to develop a landslide susceptibility map of turkey at the scale of 1 2 000 000 an index based calculation which considers six factors slope lithology local relief rainfall land use seismicity that covers the entire territory of turkey and controls the occurrence of landslides was applied in a 500 500 m pixel resolution each layer factor having various effects on landslide susceptibility has been merged into the model with assigned weights four different weight groups were assigned to the layer sets through expert judgement in order to capture the layer variability for landslide susceptibility in turkey the performances of four different weight groups were compared and evaluated by using a receiver operator characteristics curve for minimizing the uncertainty of expert judgement procedure it was observed that the w3 group was superior to the other weight groups in prediction skills the susceptibility map of w3 has been classified into five groups no low moderate high and very high susceptibility the no susceptibility class represents 4 2 of the turkish territory plains and low hills low susceptibility class 36 4 medium susceptibility 8 3 high susceptibility 47 5 and very high susceptibility class 3 6 mostly in the western and middle black sea regions respectively

probabilistic landslide susceptibility and factor effect analysis the susceptibility of landslides and the effect of landslide related factors at penang in malaysia using the geographic information system gis and remote sensing data have been evaluated landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys topographical and geological data and satellite images were collected processed and constructed into a spatial database using gis and image processing the factors chosen that influence landslide occurrence were topographic slope topographic aspect topographic curvature and distance from drainage all from the topographic database lithology and distance from lineament taken from the geologic database land use from landsat thermatic mapper tm satellite images and the vegetation index value from spot hrv high resolution visible satellite images landslide hazardous areas were analyzed and mapped using the landslide occurrence factors employing the probability frequency ratio method using the all factors to assess the effect of these factors each factor was excluded from the analysis and its effect verified using the landslide location data as a result all factors had relatively positive effects except lithology on the landslide susceptibility maps in the study area

behavior of the wyrtki jet observed with surface drifting buoys and satellite altimeter 1 analyses of up to date data from satellite tracked surface drifters indicate that the wyrtki jets wj of the equatorial indian ocean eio are developed firstly in the central eio between 75 e and 80 e and then propagate westward along the equator at speeds of about 0 7 m s 1 climatologically the fall jet is both stronger and wider than its spring counterpart this westward propagation phenomenon is supported by altimetry observation it is suggested that the westward propagation of the jets in the western eio 55 75 e is primarily forced directly by the westward propagating zonal winds whereas in the eastern eio east to 80 e propagation of the jet signals is ambiguous although the zonal wind pattern is observed moving east it is also evident that the wjs are subject to strong interannual variability which may associate with el nino southern oscillation enso and indian ocean dipole iod

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

impact of indian ocean dipole and el nino southern oscillation wind forcing on the wyrtki jets 1 interannual variability of the wyrtki jets is studied in the context of indian ocean dipole iod and el nino and southern oscillation enso wind forcing using a three dimensional numerical ocean model and observations the boreal fall october november wyrtki jet is more significantly affected than the boreal spring april may wyrtki jet since both the iod and enso tend to peak toward the end of the calendar year various statistical methods are used in an attempt to separate the impacts of the iod and enso on these jets with emphasis on the fall jet the first two modes of an empirical orthogonal function eof decomposition account for about 90 and 85 of variability in zonal currents and wind stress respectively along the equator in the indian ocean but eof analysis does not cleanly separate out iod and enso forcing and response partial correlation analysis reveals that iod wind forcing and zonal equatorial current response are stronger on average than for enso and extend further west across the basin composite analysis of iod only enso only and combined iod and enso years provides a complementary definition of the relative contributions of these two phenomena on wyrtki jet variability and in general is consistent with the results of the partial correlation analysis

deep structures of slopes connected with sandstone crags in the upland area of the świetokrzyskie holy cross mountains central poland abstract deep seated gravitational deformations of slopes are commonly observed and described in mountains but faintly manifested and thus neglected in upland areas thanks to the geophysical methods e g ert as well as detailed surface surveys and studies in caves such deformations have been discovered and described in the region of the wietokrzyskie holy cross mountains central poland which is an upland area of usually gentle slopes of a height of several tens of metres the deformations which have been studied on 20 30 m high slopes formed of sandstone series alternating with claystone siltstone and heterolithe series represent various movements from slight rotational and translational ca 1 m movements through horizontal and vertical shifts of several metres to significant dislocations of sandstone corestones embedded within the regolith forming the slopes the last mentioned structures are currently relics completely masked by subsequent slope processes and their origin should be related to specific periglacial and even sub glacial conditions of the pleistocene on the other hand as confirmed by radiocarbon dating and other mapping slight movements of relatively low slopes can even be active nowadays these deformations that occur in regions of a relatively low relief and have so far been neglected or considered to be unique are possibly even more frequent and should be studied using modern geophysical and other methods

national scale landslide susceptibility map of romania in a european methodological framework abstract landslide susceptibility maps are useful tools for risk analysis and assessment with practical implications because they provide relevant information for territorial planning land use sustainable management or even forecast and early warning systems achievement of accurate assessments of landslide susceptibility for large regions i e including national territories is still a challenge mainly because of the lack of proper landslide inventory and monitoring data romania represents one of the most landslide affected countries in europe the current study presents an approach for drawing the landslide susceptibility map at a national scale for the romanian territory in agreement with the european methodological framework promoted for small scale evaluations of landslide susceptibility the methodological approach was adapted to the specific mophostructural climatic and landuse conditions of the country as well as to the quantity and quality of the available data in order to achieve a susceptibility zonation for slides and flows for the national territory it follows a mixed statistical heuristic approach based on a spatial multi criteria evaluation smce procedure integrating both landslide information and expert knowledge the national landslide susceptibility map outlines large areas ranked as having high and very high susceptibility throughout the subcarpathian chain the moldavian and transylvanian plateaux and the getic piedmont the prediction performance was examined quantitatively and qualitatively by making use of regional geomorphical knowledge the evaluations suggest that despite uncertainties inherent at this analysis scale spatially differentiated models are able to better capture landslide conditioning frameworks and reproduce inter and especially intraregional variability of landslide distribution as compared to a previous version of the national susceptibility map the study proves that combining statistical and heuristic approaches calibrated and later on validated for distinct homogeneous morpho litho structural units allows to increase the prediction capacity of the national scale model the results are useful to public authorities at national regional county and municipality levels providing knowledge for the enhancement of disaster prevention and response plans

probabilistic sinkhole modelling for hazard assessment a method for quantitatively assessing sinkhole susceptibility spatial probability and hazard spatio temporal probability has been developed and independently tested in a 50 km2 sector of the ebro valley evaporite karst three genetic types of sinkholes have been mapped in the floodplain and a terrace surface 947 small cover collapse sinkholes type 1 terrace large collapse sinkholes type 2 floodplain and large subsidence depressions type 3 floodplain the type 1 sinkhole inventory includes two temporal populations 447 sinkholes formed before 24 november 2005 and 500 between that date and 2 november 2006 sinkhole susceptibility models have been elaborated analysing the statistical relationships between the sinkholes of the 2005 inventory and a set of potential conditioning factors the independent evaluation validation of the susceptibility models by means of several strategies random sequentially excluded and temporal has allowed us to select the most significant variables for each sinkhole type and assess quantitatively the quality of models which are reasonable for the three sinkhole types validation has also provided information on the contribution of specific variables and the effect of changing their accuracy to the prediction capability of models susceptibility models for type 3 sinkholes have been validated satisfactorily with the 2006 sinkhole inventory temporal validation the best susceptibility model has been transformed into a hazard map considering the frequency of sinkholes that occurred in each susceptibility class between 2005 and 2006 as well as their average size the susceptibility and hazard models obtained could be used as an objective basis for the application of mitigation measures either of preventive or corrective nature copyright 2008 john wiley sons ltd

the dynamics of zonal current variations in the central equatorial indian ocean 1 this paper examines the depth integrated zonal momentum balance in the central equatorial indian ocean 0 80 5 e for two periods in 1993 1994 and 2004 2006 using a combination of in situ and satellite observations one to two year record length mean balances are approximately linear and steady state monthly to seasonal time scale variations are also governed by linear dynamics with imbalances between the pressure gradient force and surface wind stress leading to zonal mass transport variations along the equator interannual variations in zonal transports along the equator associated with indian ocean dipole events in 1994 and 2006 are likewise consistent with linear dynamics these results provide a valuable benchmark for evaluating models of equatorial indian ocean circulation on seasonal time scales

intraseasonal vertical velocity variation caused by the equatorial wave in the central equatorial indian ocean intraseasonal vertical velocity variation in the central equatorial indian ocean was investigated using observations from the field experiment mirai indian ocean cruise for the study of the mjo convection onset mismo and from the research moored array for african asian australian monsoon analysis and prediction rama in october november 2006 using an array of four subsurface moored acoustic doppler current profilers adcps we estimated vertical velocity by applying the continuity equation results indicated alternating downwelling and upwelling episodes at around thermocline depth with maximum amplitudes larger than 8 0 10 5 m s 1 or about 7 m per day the vertical velocity variation was mainly produced by the divergence convergence of meridional currents with a quasi biweekly period of 11 16 days the temporal changes in temperature around thermocline depth were consistent with variations in vertical velocity whereas upwelling had less impact on the surface layer temperature intraseasonal variations in the ocean may be a part of biweekly fluctuations by remotely forced mixed rossby gravity waves which have a meridional current maximum at the equator accompanied by divergence convergence in the surface layer a few degrees from the equator

a data based landslide susceptibility map of africa abstract our understanding of the spatial patterns of landslides in africa is limited with available landslide studies typically focusing on only one or a few study areas moreover africa is clearly underrepresented in terms of available landslide inventories this study aims to produce a first continent wide landslide susceptibility map for africa calibrated with a well distributed landslide dataset we reviewed the literature on landslides in africa and compiled all available landslide inventories ca 10 800 landslides supplemented by additional landslide mapping using google earth imagery in underrepresented regions ca 7250 landslides this resulted in a dataset of approximately 18 050 landslides various environmental variables were investigated for their significance in explaining the observed spatial patterns of landslides to account for potential mapping biases in the dataset we used monte carlo simulations that selected different subsets of mapped landslides to test the significance of the considered environmental variables based on these analyses we constructed two landslide susceptibility maps for africa one for all landslide types and one excluding the known rockfalls in both maps topography is by far the most significant variable we evaluated the performance of the fitted multiple logistic regression models using independent subsets of landslides selected from the total dataset overall both maps perform very well in predicting intra continental patterns of landslides in africa and explain about 80 of the observed variance in landslide occurrence to further test the robustness and sensitivity to mapping biases we also modelled landslide susceptibility while excluding regions with arid climates as landslides in these environments are expected to be better preserved over time and therefore likely relatively overrepresented despite this potential bias the effect on the landslide susceptibility model is limited based on the constructed database and our analyses we further discuss potential research gaps for landslide prediction in africa and at continental scales for example analysis of the african countries mean landslide susceptibility shows a lack of landslide research in various countries prone to landsliding e g guinea gabon lesotho madagascar apart from the intrinsic value of this landslide susceptibility map as a natural hazard risk management tool the map and compiled database are highly promising for other applications for example we explored the potential significance of landslides as a geomorphic process by confronting our landslide susceptibility map with an available database of measured catchment sediment yield for 500 rivers in africa overall a significant positive but relatively weak relation between landslide susceptibility and sediment yield is observed

using gpr for assessing the volume of sediments from the largest natural dam lake of the eastern carpathians cuejdel lake romania cuejdel lake in the eastern carpathians romania formed in 1991 following the damming of the cuejdiu brook from torrential rainfall causing a massive landslide of natural deposits in 2011 using a bathy 500df dual frequency hydrographic echo sounder the first detailed bathymetric model of the lacustrine cuvette was produced using more than 45 000 depth readings this was the first ever use of a ground penetrating radar gpr a mala ramac x3m gpr with a 100 mhz antenna in romania for evaluating the rate of clogging of a dam lake the thickness of the alluvial deposits and the rate of clogging were determined on the basis of the measurements taken in wintertime when the ice cover was 30 45 cm the data concerning the clogging were correlated with the solid transport from the level of the catchment basin developed in the flysch area and with the sedimentation conditions of the lake the analysis of the annual non glacial varve in situ biodegradation the morphologic evolution of the lacustrine cuvette determined on the basis of three dems revealed a significant quantitative dynamics of the alluvial deposits sediment accumulation rate 1 16 cm year volume of sediments across bathymetric levels 33 6 440 4 m3 an total volume accumulated in 22 years 103 988 87 m3 which represents 8 5 of the initial volume 1 223 001 33 m3 average annual clogging rate 4521 26 m3 year or 0 36 year in 2004 cuejdel lake was declared a protected natural area accordingly no hydrotechnical works can be carried out in order to stop the erosion and implicitly the clogging

dynamics of wind forced intraseasonal zonal current variations in the equatorial indian ocean 1 this study examines the structure and dynamics of wind forced intraseasonal zonal current variability in the equatorial indian ocean we take advantage of a variety of satellite and in situ data sets including unprecedented 4 8 year long velocity time series records from the research moored array for african asian australian monsoon analysis and prediction rama program spectral analysis reveals prominent intraseasonal zonal currents variations along the equator with periods of 30 70 days these oscillations are vertically in phase above the thermocline and propagate eastward with the local zonal winds in the thermocline intraseasonal zonal velocity variations also propagate eastward across a broad range of phase speeds expected for low baroclinic equatorial kelvin waves amplitudes decrease with depth with deeper levels leading those near surface collectively these results suggest that the near surface layer responds directly to intraseasonal zonal wind stress forcing and that subsequently energy radiates downward and eastward in the thermocline in the form of wind forced equatorial kelvin waves in addition intraseasonal zonal current variability on the equator is coherent with off equatorial sea surface height fluctuations in the eastern and central of the basin this coherence is primarily due to the fact that equatorial zonal wind variations are associated with off equatorial wind stress curls that can generate local ekman pumping and westward propagating rossby waves

seismic controls on contemporary sediment export in the siret river catchment romania abstract while differences in catchment sediment yield sy t km 2 y 1 are generally attributed to topography lithology climate and land use recent studies have highlighted that also seismic activity may have an important impact on sy nonetheless relatively little is known about the importance of this factor and the processes and mechanisms explaining its influence therefore this study explores the role of seismic activity in explaining spatial and temporal variation in sediment export within the siret basin romania 45 000 km 2 a catchment with a large variability in seismic activity based on previously unpublished long term 30 years sy measurements for 38 subcatchments of the siret we analyze the correlation between average sy seismic activity and various other catchment characteristics our results showed that spatial variation in average sy was indeed strongly correlated with the degree of seismic activity in each catchment r 2 0 74 also catchment lithology explained an important part of the differences in sy r 2 0 67 the combination of these two factors accounted for about 80 of the observed variation in sy while other factors e g topography land use climate and runoff did not significantly contribute to the explained variance in average sy to explore the impact of a specific earthquake event on sediment export we analyzed daily variations in suspended sediment concentrations of 10 subcatchments five years before and after an earthquake of mw 7 4 that affected the vrancea region in 1977 and triggered a substantial number of landslides only one catchment showed a clear 3 fold increase in sediment concentrations at unit discharge for the other nine catchments no consistent increase could be observed this indicates that the impact of seismic activity on average sy is mainly indirect and not associated with sudden pulses of sediments caused by earthquake triggered landslides potential mechanisms that could explain such indirect responses are discussed

tracking natural and anthropic risks from historical maps as a tool for cultural heritage assessment a case study in this study historical maps and orthophotos were used as a baseline to establish the vulnerability of cultural heritage ch sites to natural and anthropic elements as a tool for cultural heritage management in valea oii river basin north eastern romania starting from the nineteenth century a series of natural hazards begun to have a frequent occurrence and with a higher degree of destruction as a consequence of anthropic pressure village extension connecting the human settlements by a network of roads and building ponds to save water resources the main indicators used were derived from cartographic digitisation landslides gullies villages roads and ponds gis integration and mapping allowed the creation of maps with both natural and anthropic factors following the gis analysis of ch sites located within a 50 m distance from the roads landslides and gullies 5 m for ponds and inside villages results that the highest number of ch sites 26 was affected by the development of road networks in 2012 while in 1894 only a number of three sites were affected the creation of vulnerability maps divided into three classes low moderate and high was undertaken by overlaying the cultural heritage data with the information collected from the historical maps these maps will then provide a comprehensive database to help local stakeholders policy makers and local authorities to adopt proper protection and mitigation measures

equatorial currents in the pacific ocean 1992 1997 a medium resolution ocean general circulation model of the tropical pacific ocean is used to explore current structure and variability on the equator for the period from 1992 to 1997 the model assimilates surface and subsurface temperature data from expendable bathythermographs and the tropical ocean global atmosphere tropical atmosphere ocean toga tao moorings and altimetry data from the topex poseidon satellite currents from the model are compared with current observations from the toga tao moorings at 110 w 140 w and 165 e since current data are not assimilated these data provide an independent verification of the model results the comparison shows that the model produces accurate currents over a wide range of spatial and temporal scales in particular the model correctly resolves temporal variability from instability waves with periods of less than a month to interannual changes with periods of several years the model results are used to explore zonal velocity changes associated with the onset of the 1997 1998 el nino southern oscillation enso event the event began with a series of equatorial kelvin waves which were excited by westerly wind bursts in the western pacific and propagated to the eastern pacific the passage of these waves is associated with an initial strengthening of the equatorial undercurrent euc followed by a rapid shutdown of the euc the weakening of the undercurrent during enso is consistent with previous descriptions and results from the collapse of the easterly trade winds in the western pacific

integration of the statistical index method and the analytic hierarchy process technique for the assessment of landslide susceptibility in huizhou china abstract a landslide susceptibility assessment was accomplished in huizhou guangdong province by adopting the statistical index method and the analytic hierarchy process eight landslide causing factors were considered including elevation slope aspect lithology land cover distance to a fault distance to a road distance to a river and precipitation the statistical index method was used to determine the weighted value si for classes of every landslide causing factor the analytic hierarchy process was utilized to determine the weighted value wi for every factor and the summation of the product of si by wi represent the landslide susceptibility index lsi value for every pixels based on the derived lsi the study area was grouped into five susceptibility classes in the study area the densities of landslide for five susceptibility classes from very high to very low show a linear increasing trend implying there is a satisfactory agreement between the susceptibility map and the actual landslide data the roc curves for training and prediction datasets suggest that the model could have a reasonably good predictive capability the landslide susceptibility map derived in this study shows the settlement and sparse forest area with lithology of unit ii red layered moderate soft mixture of clastic rocks unit iii layered moderate hard to hard mixture of clastic rocks and unit v massive moderate hard to hard mixture at the elevation of 0 200 m are the most susceptible to slope failure the result could be very useful in identification of the most problematic areas which is very critical for investigating landslide hazard and risk management and community regional planning

equatorial indian ocean subsurface current variability in an ocean general circulation model the variability of subsurface currents in the equatorial indian ocean is studied using high resolution ocean general circulation model ogcm simulations during 1958 2009 february march eastward equatorial subsurface current esc shows weak variability whereas strong variability is observed in northern summer and fall esc an eastward subsurface current with maximum amplitude in the pycnocline is prominent right from summer to winter during strong indian ocean dipole iod years when air sea coupling is significant on the other hand during weak iod years both the air sea coupling and the esc are weak this strongly suggests the role of esc on the strength of iod the extension of the esc to the summer months during the strong iod years strengthens the oceanic response and supports intensification and maintenance of iods through modulation of air sea coupling although the esc is triggered by equatorial winds the coupled air sea interaction associated with iods strengthens the esc to persist for several seasons thereby establishing a positive feedback cycle with the surface this suggests that the esc plays a significant role in the coupled processes associated with the evolution and intensification of iod events by cooling the eastern basin and strengthening thermocline sst sea surface temperature interaction as the impact of iod events on indian summer monsoon is significant only during strong iod years understanding and monitoring the evolution of esc during these years is important for summer monsoon forecasting purposes there is a westward phase propagation of anomalous subsurface currents which persists for a year during strong iod years whereas such persistence or phase propagation is not seen during weak iod years supporting the close association between esc and strength of air sea coupling during strong iod years in this study we report the processes which strengthen the iod events and the air sea coupling associated with iod it also unravels the connection between equatorial indian ocean circulation and evolution and strengthening of iod

receiver function studies in the trans hudson orogen saskatchewan teleseismic events were recorded on an array of three component broadband and short period seismographs in the trans hudson orogen over a period of almost 3 years receiver functions calculated from these data were used in a forward modelling study to derive the local shear wave velocity structure beneath 20 stations station ffc flin flon located within the flin flon belt was one of two stations situated on bedrock and produced the highest quality receiver functions the ffc velocity model correlates well with an interpretation of nearby reflection data and features a distinct lower crust interpreted as archean basement which cores the entire reindeer zone both radial and tangential receiver functions at ffc show strong evidence for a northeasterly dipping shallow boundary within rocks of the flin flon belt with a dip angle of 20 total crustal thickness is 37 km eighteen stations are situated on phanerozoic sedimentary cover ranging in thickness from 0 4 km to greater than 2 km receiver function

interpretation of a seismic refraction survey across the arabian shield in western saudi arabia abstract in february 1978 seismic refraction profiles were recorded by the u s geological survey along a 1000 km line across the arabian shield in western saudi arabia this report presents a traveltime and relative amplitude study in the form of velocity depth functions for each individual profile assuming horizontally flat layering the corresponding cross section of the lithosphere showing lines of equal velocity reaches to a depth of 60 80 km the crust thickens abruptly from 15 km beneath the red sea rift to about 40 km beneath the arabian shield the upper crust of the western arabian shield yields relatively high velocity material at about 10 km depth underlain by velocity inversions while the upper crust of the eastern shield is relatively uniform the lower crust with a velocity of about 7 km s is underlain by a transitional crust mantle boundary for the lower lithosphere beneath 40 km depth the data indicate the existence of a laterally discontinuous lamellar structure where high velocity zones are intermixed with zones of lower velocities beneath the crust mantle boundary of the red sea rift most probably strong velocity inversions exist here the data do not allow a detailed modelling velocities as low as 6 0 km s seem to be encountered between 25 and 44 km depth

seasonal to interannual time scale dynamics of the equatorial undercurrent in the indian ocean abstractthis paper investigates the structure and dynamics of the equatorial undercurrent euc of the indian ocean by analyzing in situ observations and reanalysis data and performing ocean model experiments using an ocean general circulation model and a linear continuously stratified ocean model the results show that the euc regularly occurs in each boreal winter and spring particularly during february and april consistent with existing studies the euc generally has a core depth near the 20 c isotherm and can be present across the equatorial basin the euc reappears during summer fall of most years with core depth located at different longitudes and depths in the western basin the euc results primarily from equatorial kelvin and rossby waves directly forced by equatorial easterly winds in the central and eastern basin however reflected rossby waves from the eastern boundary play a crucial role while the first two baroclinic modes make the largest contribution intermediate modes 3 8 are also

variability of zonal currents in the eastern equatorial indian ocean on seasonal to interannual time scales this study examines equatorial zonal current variations in the upper layers of eastern indian ocean in relation to variations in the indian ocean dipole iod the analysis utilizes data from the research moored array for african asian australian monsoon analysis and prediction rama and the european centre for medium range weather forecasts ocean reanalysis system 4 ecmwf oras4 surface currents are characterized by semiannual eastward flowing wyrtki jets along the equator in boreal spring and fall forced by westerly monsoon transition winds the fall jet intensifies during negative iod niod events when westerlies are anomalously strong but significantly weakens during positive iod piod events when westerlies are anomalously weak as zonal wind stress weakens during piod events sea surface height becomes unusually low in the eastern basin and high in the west setting up an anomalous pressure force that drives increased eastward transport in the thermocline opposite tendencies are evident during niod events in response to intensified equatorial westerlies current transport adjustments to anomalous zonal wind forcing during iod events extend into the following year consistent with the cycling of equatorial wave energy around the basin a surface layer mass budget calculation for the eastern sea surface temperature sst pole of the iod indicates upwelling of 2 9 0 7 sv during normal periods increasing by 40 50 during piod events and reducing effectively to zero during niod events iod related variations in wyrtki jet and thermocline transports are major influences on these upwelling rates and associated water mass transformations which vary consistently with sst changes

application of analytic hierarchy process frequency ratio and statistical index to landslide susceptibility an approach to endangered cultural heritage this paper presents the applicability of the analytic hierarchy process frequency ratio and statistical index in landslide susceptibility mapping for an area from north eastern romania the dependent factor in this case the landslides was determined by combining seven conditioning factors elevation slope angle curvature normalised difference vegetation index roughness distance to rivers and landforms a landslide inventory was prepared using topographic plans and orthophotos and by carrying out field surveys with the total station leica tcr1201 and geodetic gps leica system 1200 in rtk mode the final susceptibility maps were made with the help of gis and validated by carrying out the receiver operating characteristics roc curves roc plots for training data have shown that the susceptibility map generated using the analytic hierarchy process with auc value of 79 46 has a better prediction accuracy compared with frequency ratio method auc 75 24 and statistical index method which had an auc value of 61 46 the prediction rate of the three models is over 50 79 64 for the analytic hierarchy process model 75 65 for the frequency ratio model and 66 36 for the statistical index model more than a half of the cultural heritage sites are located in areas with a very high and high vulnerability to landslides taking into consideration that multi stratified settlements are located in areas with low and medium landslide susceptibility this fact can indicate a possible awareness of prehistoric people from natural hazards the final susceptibility maps can be used for land use planning risk reduction hazard mitigation to evaluate the present state of cultural heritage sites in danger and to predict which of the sites will be in more danger in the future

slow variability in the equatorial west central pacific in relation to enso abstract six years of upper ocean velocity temperature and surface wind data collected in the west central pacific at 0 170 w reveal a slow ocean dynamical mode associated with the el nino southern oscillation enso latent and sensible heat flux calculations using the basin wide tropical atmosphere ocean tao array data show a coincident slow ocean atmosphere thermodynamical mode beginning with the la nina conditions in 1988 through the peak el nino conditions in 1992 the equatorial undercurrent euc speed decreased along with the surface zonal wind stress and the zonal pressure gradient simultaneous with these were increasing trends in the richardson number above the euc core and in sea surface temperature sst after peak warming was achieved the variations in all of these quantities reversed in a movement toward their previous la nina conditions as this evolved within the ocean the sensible and latent heat fluxes increased with large values emanating eastward from the western pacific the

lithospheric structure of the arabian shield from the joint inversion of receiver functions and surface wave group velocities abstract we estimate lithospheric velocity structure for the arabian shield by jointly modeling receiver functions and fundamental mode group velocities from events recorded by the 1995 1997 saudi arabian portable broadband deployment receiver functions are primarily sensitive to shear wave velocity contrasts and vertical travel times and surface wave dispersion measurements are sensitive to vertical shear wave velocity averages so that their combination bridge resolution gaps associated with each individual data set our resulting models correlate well with the observed surface geology the asir terrane to the west consists of a 10 km thick upper crust of 3 3 km s overlying a lower crust of 3 7 3 8 km s in the afif terrane to the east the upper crust is 20 km thick and has an average velocity of 3 6 km s and the lower crust is about 3 8 km s separating the terranes the nabitah mobile belt is made of a gradational upper crust up to 3 6 km s at 15 km overlying an also gradational lower crust up to 4 0 km s the crust mantle transition is found to be sharp in terranes of continental affinity east and gradual in terranes of oceanic affinity west the upper mantle shear velocities range from 4 3 to 4 6 km s temperatures around 1000 c are obtained from our velocity models for a thin upper mantle lid observed beneath station taif and suggest that the lithosphere could be as thin as 50 60 km under this station

magnetic properties of early pliocene sediments from iodp site u1467 maldives platform reveal changes in the monsoon system we report a study of the magnetic stratigraphy and the anisotropy of isothermal remanent magnetization of pliocene sediments from international ocean discovery program iodp site u1467 drilled in the maldives platform indian ocean during exp 359 magnetic stratigraphy gives a precise record of geomagnetic reversals of the early pliocene from approximately 5 3 ma to 3 1 ma providing a detailed age model in an interval where the biostratigraphic record is scarce we use the anisotropy of isothermal remanent magnetization airm to investigate the statistical orientation of fine magnetic particles and provide data on the strength and direction of bottom currents during the early pliocene the strength of bottom currents recorded by the airm shows a prominent increase at the top of chron c3n 1n about 4 2 ma and the current direction ne sw is consistent with that of modern instrumental measurements since bottom currents in the maldives are driven by the monsoon we speculate that the 4 2 ma increase of bottom currents could mark the onset of the present day setting probably related to the coeval uplift phase of the himalayan plateau

comparison of gis based landslide susceptibility models using frequency ratio logistic regression and artificial neural network in a tertiary region of ambon indonesia abstract this study aims to evaluate landslide causative factors in landslide susceptibility assessments and to compare landslide susceptibility models based on the bivariate frequency ratio fr multivariate logistic regression lr and artificial neural network ann the majority of landslide occurrences in ambon indonesia is induced by heavy rainfall events where slope failures occur mostly on steep slopes thereby endangering municipality areas at the base of the hills eight landslide causative factors were considered in the landslide susceptibility assessments the causative factors were elevation slope angle slope aspect proximity to stream network lithology density of geological boundaries proximity to faults and proximity to the road network the output susceptibility maps were reclassified into five classes ranging from very low to very high susceptibility using jenks natural breaks method twenty percent of all mapped landslides were used as the validation of the susceptibility models the validity and the accuracy of each model were tested by calculating areas under receiver operating characteristic curves rocs and the areas under the curve auc for the success rate curves of fr lr and ann were 0 688 0 687 and 0 734 respectively the auc for the prediction rate curve of fr lr and ann were 0 668 0 667 and 0 717 respectively all findings of the models show good results with the accuracy of all models being higher than 66 the ann method proved to be superior in explaining the relationship of landslide with each factor studied