a limited area model of the gulf stream design initial experiments and model data intercomparison abstract a primitive equation n layer eddy resolving creation model has been applied to the gulf stream system from cape hatteras to cast of the grand banks 78 45 w 30 48 n within the limitations of the model realistic coastlines bottom topography and forcing functions have been used a two layer version of the model was driven by observed mean climatological wind forcing and mass transport prescribed at inflow outflow was determined by a radiation boundary condition and an integral constraint on the mass field in each layer specification of a deep western boundary current dwbc was included in some model runs six numerical experiments from a series of over fifty integrated to statistical equilibrium were selected for detailed description and intercomparison with observations the basic case consisted of a flat bottom regime driven by wind forcing only realistic inflow transport in the upper layer was then prescribed and two different outflow specifications at the eastern boundary were s

sedimentological characteristics and application of machine learning techniques for landslide susceptibility modelling along the highway corridor nahan to rajgarh himachal pradesh india abstract the aim of this study is to investigate the causes of landslides in the himalayan region and analysis of their sedimentary characteristics the himalayan region is unique to topographic as well as geological formations each range has different litho tectonic setting such as the siwalik the lesser andthe great himalayan ranges particularly the lesser himalayan ranges are highly susceptible to landslide during the monsoon season in this study a highway corridor is selected passing through the siwalik and the lesser himalayan range the study comprises of two parts a investigates landslide sedimentary characteristics such as particle size plasticity limit slope geometry and land cover b comparative analysis of four machine learning methods to find out a best suitable model for landslide susceptibility analysis in order to achieve the objectives detailed landslide inventory of the area is prepared based on repeated field visits and multi dated satellite imageries the field investigation reveals that debris fall and debris flow mostly confined a along the road in proximity to the streams particularly in scrubs and wasteland and b along the streams due to river undercutting process sedimentological characteristics are examined to understand the grain size plasticity limit rock mass strength and its relationship to slope failure mechanism landslide susceptibility is analyzed using boosted regression tree brt generalized linear model glm random forest rf and support vector machine svm for the study area these model results are validated using landslide test dataset with the area under curve auc method the auc values of brt 0 85 glm 0 786 rf 0 904 and svm 0 865 reveals the high prediction rate for spatial modelling of landslide in the area the validation results show satisfactory agreement between the computed landslide susceptibility maps and the existing landslides occurred along the highway corridor

on the spatial relationship between landslides and causative factors on lantau island hong kong abstract this paper presents a statistical approach to study the spatial relationship between landslides and their causative factors at the regional level the approach is based on digital databases and incorporates such methods as statistics spatial pattern analysis and interactive mapping firstly the authors propose an object oriented conceptual model for describing a landslide event and a combined database of landslides and environmental factors is constructed by integrating the various databases within such a conceptual framework the statistical histogram spatial overlay and dynamic mapping methods are linked together to interactively evaluate the spatial pattern of the relationship between landslides and their causative factors a case study of an extreme event in 1993 on lantau island indicates that rainfall intensity and the migration of the center of the rainstorm greatly influence the occurrence of landslides on lantau island a regional difference in the relationship between landslides and topography is identified most of the landslides in the middle and western parts of the island occurred on slopes with slope angles of 25 35 while in the eastern part the corresponding range is 30 35 overlaying landslide data with land cover reveals that a large number of landslides occurred in the bareland and shrub covered area and in the transition zones between different vegetation types the proposed approach can be used not only to analyze the general characteristics of such a relationship but also to depict its spatial distribution and variation thereby providing a sound basis for regional landslide prediction

using multiple logistic regression and gis technology to predict landslide hazard in northeast kansas usa abstract landslides in the hilly terrain along the kansas and missouri rivers in northeastern kansas have caused millions of dollars in property damage during the last decade to address this problem a statistical method called multiple logistic regression has been used to create a landslide hazard map for atchison kansas and surrounding areas data included digitized geology slopes and landslides manipulated using arcview gis logistic regression relates predictor variables to the occurrence or nonoccurrence of landslides within geographic cells and uses the relationship to produce a map showing the probability of future landslides given local slopes and geologic units results indicated that slope is the most important variable for estimating landslide hazard in the study area geologic units consisting mostly of shale siltstone and sandstone were most susceptible to landslides soil type and aspect ratio were considered but excluded from the final analysis because these variables did not significantly add to the predictive power of the logistic regression soil types were highly correlated with the geologic units and no significant relationships existed between landslides and slope aspect

single quartz grain electron spin resonance esr dating of a contemporary desert surface deposit eastern desert egypt abstract signal resetting by sunlight prior to burial is a crucial assumption in electron spin resonance esr dating of sediments this resetting process is expected to be completed to a greater extent in arid than in fluvial environments the present paper investigates the natural and artificially irradiated signal intensity of ti related centres in single quartz grains collected from the desert surface eastern desert egypt in order to test this hypothesis the results suggest that in most grains both the ti li and ti h signal are completely reset to zero additive dose curves based on the sum of both ti centres show an anomaly in the low dose region possible causes for this behaviour are briefly discussed three fitting procedures are conducted and each of them shows a different palaeodose distribution with a rather large spread in d e values it is concluded that similar fossil deposits would be datable by single grain esr using q band measurements of the ti li or ti h signals in quartz

a hybrid fuzzy weight of evidence method in landslide susceptibility analysis on the wuyuan area china abstract the present study proposed a hybrid fuzzy weight of evidence model for constructing a landslide susceptibility map in the wuyuan area china where disastrous landslide events have occurred the model combines the knowledge of experts obtained through a fuzzy logic approach and a hybrid weight of evidence method the estimated knowledge based fuzzy membership value of each environmental variable is combined with data based conditional probabilities to derive fuzzy posterior probabilities and landslide susceptibility the developed model was compared with a landslide susceptibility map produced using the data driven weight of evidence method based on 510 landslide and non landslide sites the sites were identified by analyzing airborne imagery field investigation and previous studies landside susceptibility for these sites was analyzed using 10 geo environmental variables slope aspect lithology soil rainfall plan curvature the normalized difference vegetation index distance to roads distance to rivers and distance to faults the resultant hybrid fuzzy weight of evidence method showed high predictive power with the area under the success and predictive curves being 0 770 and 0 746 respectively additional analyses showed that the developed model could work effectively even with limited data

landslide susceptibility analysis using gis and artificial neural network the purpose of this study is to develop landslide susceptibility analysis techniques using an arti cial neural network and to apply the newly developed techniques to the study area of yongin in korea landslide locations were identi ed in the study area from interpretation of aerial photographs eld survey data and a spatial database of the topography soil type and timber cover the landslide related factors slope curvature soil texture soil drainage soil effective thickness timber age and timber diameter were extracted from the spatial database using those factors landslide susceptibility was analysed by arti cial neural network methods the landslide susceptibility index was calculated by the back propagation method which is a type of arti cial neural network method and the susceptibility map was made with a geographic information system gis program the results of the landslide susceptibility analysis were veri ed using landslide location data the validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide location a gis was used to ef ciently analyse the vast amount of data and an arti cial neural network to be an effective tool to maintain precision and accuracy the results can be used to reduce hazards associated with landslides and to plan land use and construction copyright 2003 john wiley sons ltd

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

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

debris flow susceptibility mapping using frequency ratio and seed cells in a portion of a mountain international route dry central andes of argentina abstract debris flow and floods represent one of the main natural hazards that impact transport infrastructure causing serious damage economic losses and hinder regional economic development these processes are eventually associated with massive traffic cuts and direct damage to road structures to enable the prevention of such consequences this paper employs statistical modeling techniques various instability factors and geomorphological mapping to generate debris flow susceptibility maps in a portion of an important route on the dry andes of san juan in the agua negra river basin argentina a debris flows inventory map was prepared using satellite images and field checks the debris flows inventory was randomly divided into a model dataset 80 47 debris flows and remaining 20 12 debris flows data was used for validation purpose the instability factors chosen that influence debris flows occurrence were elevation slope angle slope aspect solar radiation topographic wetness index stream power index topographic position index melton ruggedness number terrain ruggedness index sediment transport capacity index plan curvature profile curvature lithology distance to road and proximity to stream using these factors six different models of debris flow susceptibility were calculated by frequency ratio fr lithology igneous complex was found to be important debris flows related factor in the study area the precision of the results was evaluated by receiver operating characteristic roc analysis according to the area under the curve auc the models of all flow track and natural breaks and all flow track and geometrical interval were 0 83 and 0 84 respectively showing a practically identical predictive capacity

little ice age nivation activity in northeast greenland during the little ice age lia the periglacial landscape in northeast greenland responded rela tively quickly to the climatic deterioration with increased nivation activity resulting nivation landforms and associated sediment basins are used as palaeoclimatic archives documenting the significant geomorphological effect of nivation during the lia period in the zackenberg area a nival basin studied in detail showed the onset and dominance of niveo fluvial sedimentation in the period ad 1250 1420 followed by increasing niveo aeolian sedimentation between ad 1420 1500 1580 finally very rapid niveo aeolian sedimentation prevailed during the period ad 1500 1580 1690 in the same period some large nival fans accumulated in the zackenberg lowland as a result of increased niveo fluvial activity and niveo fluvial sediments were also deposited in pre existing fluvial valleys demonstrating the large areal extension of the nivation activity the chronology is based on nine ams 14c determinations the inte

frequency ratio model based landslide susceptibility mapping in lower mae chaem watershed northern thailand the purpose of this study is to produce a landslide susceptibility map for the lower mae chaem watershed northern thailand using a geographic information system gis and remotely sensed images for this purpose past landslide locations were identified from satellite images and aerial photographs accompanied by the field surveys to create a landslide inventory map ten landslide inducing factors were used in the susceptibility analysis elevation slope angle slope aspect lithology distance from lineament distance from drainage precipitation soil texture land use land cover lulc and ndvi the first eight factors were prepared from their associated database while lulc and ndvi maps were generated from landsat 5 tm images landslide susceptibility was analyzed and mapped using the frequency ratio fr model that determines the level of correlation between locations of past landslides and the chosen factors and describes it in terms of frequency ratio index finally the output map was validated using the area under the curve auc method where the success rate of 80 06 and the prediction rate of 84 82 were achieved the obtained map can be used to reduce landslide hazard and assist with proper planning of lulc in the future

gis based logistic regression for landslide susceptibility mapping of the zhongxian segment in the three gorges area china abstract a detailed landslide susceptibility map was produced using a logistic regression method with datasets developed for a geographic information system gis known as one of the most landslide prone areas in china the zhongxian shizhu segment in the three gorges reservoir region of china was selected as a suitable case to evaluate the frequency and distribution of landslides the site covered an area of 260 9 km 2 with a landslide area of 5 3 km 2 four data domains were used in this study remote sensing products thematic maps geological maps and topographical maps all with 25 25 m 2 pixels or cells statistical relationships for landslide susceptibility were developed using landslide and landslide causative factor databases we extended the application of logistic regression approaches to use all continuous variables as they are and the landslide density is used to transform these nominal variables to numeric variable according to the map 2 8 of the study area was identified as an area with very high susceptibility whereas very low low medium and high susceptibility zones covered 18 2 36 2 26 7 and 16 1 of the area respectively the quality of susceptibility mapping was validated and the correct classification percentage and root mean square error rmse values for the validation data were 81 4 and 0 392 respectively

use of an artificial neural network for analysis of the susceptibility to landslides at boun korea the purpose of this study was to develop landslide susceptibility analysis techniques using artificial neural networks and to apply the resulting techniques to the study area of boun in korea landslide locations were identified in the study area from interpretation of aerial photographs and field survey data a spatial database of the topography soil type timber cover geology and land cover was constructed and the landslide related factors were extracted from the spatial database using these factors the susceptibility to landslides was analyzed by artificial neural network methods the results of the landslide susceptibility maps were compared and verified using known landslide locations at another area yongin in korea a geographic information system gis was used to analyze efficiently the vast amount of data and an artificial neural network turned out to be an effective tool to analyze the landslide susceptibility

gis based weights of evidence modelling of rainfall induced landslides in small catchments for landslide susceptibility mapping landslide susceptibility mapping is a vital tool for disaster management and planning development activ ities in mountainous terrains of tropical and subtropical environments in this paper the weights of evidence modelling was applied within a geographical information system gis to derive landslide susceptibility map of two small catchments of shikoku japan the objective of this paper is to evaluate the importance of weights of evidence modelling in the generation of landslide susceptibility maps in relatively small catchments having an area less than 4 sq km for the study area in moriyuki and monnyu catchments northeast shikoku island in west japan a data set was generated at scale 1 5 000 relevant thematic maps representing various factors e g slope aspect relief flow accumulation soil depth soil type land use and distance to road that are related to landslide activity were generated using field data and gis techniques both catchments have homogeneous geology and only consist of cretaceous granitic rock thus bedrock geology was not considered in data layering during gis analysis success rates were also estimated to evaluate the accuracy of landslide suscepti bility maps and the weights of evidence modelling was found useful in landslide susceptibility mapping of small catchments

sedimentology of cold climate aeolian sandsheet deposits in the askja region of northeast iceland active aeolian sandsheets cover an area of 270 km2 in the askja region of ne iceland the sandsheet is divided into i a deflationary upwind part that is characterised by deflation lags ventifacted boulder fields and restricted aeolian sand patches in the lee of obstacles ii an accumulating central part that is characterised by continuous aeolian sand cover up to 10 m thick where three scales of aeolian ripples are evident along with larger scale forms including longitudinal zibars and iii a downwind part that is currently subject to aeolian bypass with only localised accumulation occurring in topographic hollows between basaltic lava fields trains of aeolian granule megaripples are a characteristic landform of the downwind part of the sandsheet these sinuous crested oblique bedforms attain heights of 0 35 m and downwind spacings of 6 m they are composed principally of low density pebble grade pumice clasts and other reworked volcaniclastic detritus derived from the nearby askja volcanic centre the distribution of landforms across the sandsheet reflects a regional aeolian sediment budget that is controlled by dynamic interactions between glacial ice margin fluvial aeolian and volcaniclastic processes under the influence of a distinctive climatic regime sediment supply at the upwind sandsheet margin adjacent to the dyngjujokull glacier increases during summer periods when rates of glacial ablation are at a maximum longer term controls on sediment supply rate are determined by episodes of glacier surging and retreat and by periodic eruptions of volcaniclastic debris from the askja volcanic centre the availability of sediment for aeolian transport is controlled by the level of the groundwater table the depth and continuity of the permafrost layer in the proglacial area the degree of development of armoured pebble lags and freezing of the sandsheet surface during winter months the transport capacity of the wind varies on a seasonal basis with mean wind velocities and wind gustiness reaching a maximum during winter periods both winter and summer mean wind velocities have been steadily increasing since formal records began in 1969 the suite of aeolian landforms developed within the askja region as defined by sediment texture and composition and bedform scale morphology and spatial distribution reflects a special set of controlling circumstances which mean that the askja sandsheet deposits differ significantly from those described from elsewhere

slope vulnerability to earthquakes at subregional scale using probabilistic techniques and geographic information systems abstract the susceptibility of slopes to failure during earthquakes is calculated in terms of critical horizontal acceleration on a subregional scale for the upper part of the serchio river basin tuscany italy according to the working scale 1 10 000 and to the availability and accuracy of the input data the infinite slope analysis was judged to be the most appropriate method but particular attention was devoted to the error evaluation due to spatial variability of the geotechnic geometric and hydrologic parameters a geologic geomorphologic and hydrologic survey of the area was therefore performed and the geotechnic parameters were collected at local administrations all the data were stored in a gis used as a tool to build the spatial and attribute data base and to prepare the input data layers for the stability analysis in order to assess the variability of geotechnic parameters a statistical analysis was performed to assign the best fitting probability distribution to cohesion angle of internal friction and unit weight of the soil as hydrogeologic data were not available for the area only surface hydrology information could be used a map of probability of spring occurrences was derived by a bayesian method the weight of evidence modelling and was used as groundwater indicator a monte carlo procedure and a first order second moment method were applied and compared as error estimators in assessing the slope susceptibility to failure the differences between the two methods are discussed and two maps showing respectively the critical horizontal acceleration and the probability of failure associated with each slope are presented together with the curve plotting the reliability index against the probability of failure

assessment of shallow landslide susceptibility by means of multivariate statistical techniques several multivariate statistical analyses have been performed to identify the most influential geological and geomorphological parameters on shallow landsliding and to quantify their relative contribution a data set was first prepared including more than 30 attributes of 230 failed and unfailed slopes the performance of principal component analysis t test and one way test allowed a preliminary selection of the most significant variables which were used as input variables for the discriminant analysis the function obtained has classified successfully 88 5 per cent of the overall slope population and 95 6 per cent of the failed slopes slope gradient watershed area and land use appeared as the most powerful discriminant factors a landslide susceptibility map based on the scores of the discriminant function has been prepared for ensija range in the eastern pyrenees an index of relative landslide density shows that the results of the map are consistent copyright 2001 john wiley sons ltd language en

seismically induced landslide displacements a predictive model newmark s model for predicting earthquake induced landslide displacements provides a simple way to predict the coseismic displacements affecting a sliding mass subject to earthquake loading in this model seismic slope stability is measured in terms of critical acceleration which depends on the mechanical soil properties pore pressure distribution and slope geometry the triggering seismic forces are investigated in terms of energy radiation from the source propagation and site effects based on 190 accelerometric recordings from 17 italian earthquakes with magnitudes between 4 5 and 6 8 the method is based on the calibration of relations having the general form of an attenuation law that relates the energy of the seismic forces to the dynamic shear resistances of the sliding mass to propagate the expected landslide displacements as an inverse function of the distance from the fault rupture the amount of displacement computed through these relations provides a criterion to predict the occurrence of slope failures finally maps showing in a deterministic and a probabilistic way the potential of seismically induced landslide displacements are displayed as a tool to provide seismic landslide scenarios and earthquake induced landslide hazard maps respectively

an objective method to rank the importance of the factors predisposing to landslides with the gis methodology application to an area of the apennines valnerina perugia italy the present work aims at contributing to further our knowledge on the predisposing factors to landslides as well as proposing a method that allows us to weigh up as objectively as possible the influence that the various factors have on landslides in order to construct a realistic map of potential landslide hazards in order to assess the differential incidence of very predisposing factor to landslides maps of the various factors considered were drawn up with the aid of idrisi software 1997 the factors were as follows the distance from faults parallelism between the fractures and the landslide scarps land use lithology distance from the streams orientation and steepness of slopes orientation of layers compared to the slope the global analysis of the different incidence of the factors analyzed on the landslides present in the study area was carried out by comparing the respective maps with that of the scarps in this way the number of pixels forming the scarps which fell into the various classes of the maps was calculated the result thus obtained can form the basis of an objective assignation of the different ratings to be attributed to the various factors under consideration in fact the analysis carried out in this study has shown that the factors act differently and for every factor only some of the classes considered have marked importance

improving landslide susceptibility mapping using morphometric features in the mawat area kurdistan region ne iraq comparison of different statistical models abstract susceptibility mapping provides information about vulnerable locations and thus helps to potentially decrease infrastructure damage due to mass wasting during the past decades expansion of settlements into areas prone to landslides in iraq has highlighted the importance of accurate landslide susceptibility studies the main goal of this research is to implement selected morphometric parameters to improve prediction of landslide susceptibility in the zagros mountain region we used the mawat area in the kurdistan region ne iraq to test the added value of morphometric indicators sixteen morphometric factors mainly derived from a digital elevation model dem extracted using the stereo ability of the advanced spaceborne thermal emission and reflection radiometer aster satellite as well as geological and environmental predictive factors were appraised we evaluated and compared frequency ratio fr weight of evidence woe logistic regression lr and probit regression pr approaches in combination with morphometric indices to determine the landslide susceptibility ls the areas under the curve auc of the prediction rate curve prc relative landslide density index r index and true positive percentage tpp for the four models show that all models perform similarly and the focus should be on careful selection of the predictive factors which is far more important than the methods used results indicate that lithology and slope aspects are the more dominant factors that lead to detect possible occurrence of landslides furthermore this work demonstrates that the hypsometric integral performs better than the commonly used slope curvature as a predictor and thus increases the prediction accuracy of the susceptibility map we argue that the use of adequate morphometric parameters can increase the efficiency of the ls mapping in other regions of the world

quaternary sandstones northeast jordan age depositional environments and climatic implications abstract osl dating of weakly consolidated root bound non calcareous quartz arenites in northeast jordan currently assigned to the plio pleistocene azraq formation suggests a middle pleistocene 652 47 ka age the sandstones are up to 15 5 m thick and overlain by a 2 5 m thick holocene gypcrete caprock facies and textural analyses suggest that the sandstones are predominantly aeolian in origin mainly derived from tertiary sediments exposed close to the depositional site the sands were transported by the prevailing nw winds and deposited in a broad relatively flat sand sheet environment rhizoliths occur throughout the sandstones mainly as long downward tapering vertical tap roots rarely branched and with few laterals microscopic examination of root cores replaced by carbonate reveals the presence of alveolar fabrics possible needle fibre calcite calcified organic filaments of fungal root vessel and root hair origins characteristic of low magnesium beta calcretes typical of humid climates morphologically the roots resemble modern shrub like species typical of desert environments where water availability at the surface and in the subsurface was sufficient to support an effective vegetation cover plots of stratigraphic variations in root length root spacing and root frequency reflect temporal variations in the water table level and precipitation during sand deposition all three parameters show a similar crude cyclicity consistent with fluctuations in the level of the water table with the most moist phase beneath the predominantly waterlain holocene gypcrete when trees appeared for the first time the gypcrete signifies a change to temporary wetter conditions and may mark the boundary between the pleistocene and holocene in this area although pedogenic horizonation is poorly developed especially in desert sands the beta calcretes and rhizocretions typically form within active soil zones soils do not form where rainfall is

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

improving sinkhole hazard models incorporating magnitude frequency relationships and nearest neighbor analysis abstract this work presents a methodology for elaborating sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process the proposed approach has been tested in a sector of the ebro valley mantled evaporite karst where sinkholes largely induced by irrigation practices have a very high occurrence rate 50 sinkholes km 2 yr in this area covering 10 km 2 a total of 943 new cover collapse sinkholes were inventoried in 2005 and 2006 multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 sinkholes and different sets of variables including the nearest sinkhole distance the quantitative evaluation of the prediction capability of these models using the 2006 sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions the incorporation of the indirect variable nearest sinkhole distance has contributed significantly to increase the quality of the models despite simplifying the modeling process by using categorical rather than continuous variables the best susceptibility model generated with the total sinkhole population and the selected method and variables has been transformed into a hazard model that provides minimum estimates of the spatial temporal probability of each pixel to be affected by sinkholes of different diameter ranges this transformation has been carried out combining two equations derived from the more complete 2006 sinkhole population one of them expressing the expected spatial temporal probability of sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces which control the strength of the surface layer and the size of the sinkholes the presented method could be applied to predict the spatial temporal probability of events with different magnitudes related to other geomorphic processes e g landslides

gis based landslide susceptibility mapping for a problematic segment of the natural gas pipeline hendek turkey a segment of natural gas pipeline was damaged due to landsliding near hendek re routing of the pipeline is planned but it requires the preparation of a landslide susceptibility map in this study the statistical index wi and weighting factor wf methods have been used with gis to prepare a landslide susceptibility map of the problematic segment of the pipeline for this purpose thematic layers including landslide inventory lithology slope aspect elevation land use land cover distance to stream and drainage density were used in the study area landslides occur in the unconsolidated to semi consolidated clayey unit and regolith the wf method gives better results than the wi method lithology is found to be the most important aspect in the study area based on the findings obtained in this study the unconsolidated to semi consolidated clayey unit and alluvium should be avoided during re routing agricultural activities should not be allowed in the close vicinity of the pipeline

a new nested boundary condition for a primitive equation ocean model nested boundary techniques are developed based on the results of perkins 1993 and blake 1991 we focus on the numerical and physical consistency needs across the nested boundary these techniques replace the transition zone used by other researchers with a numerically and a physically based correction step we demonstrate our method using a nested reduced gravity version of the naval research laboratory nrl primitive equation ocean model and a two layer hydrodynamic finite depth version of the same model numerical experiments are performed using integrations of both an idealized double gyre and a realistic greenland iceland norwegian gin sea configuration to illustrate the need for improved boundary treatment we present a numerical study of boundary errors the study illustrates the fragile nature of nested boundary conditions with even small errors a dramatic impact is observed on the formation or lack thereof of the atlantic norwegian current which is responsible for transporting north atlantic water to the arctic ocean in the gin sea configuration

open boundary conditions for tidally and subtidally forced circulation in a limited area coastal model using the regional ocean modeling system roms in limited area ocean models open boundary conditions obcs often create dynamic inconsistencies and perform poorly in resolving tidal or subtidal flow when both forces exist orlanski type radiation obcs are reasonably efficient at treating the subtidally forced flow and flather type obcs are commonly adapted for the tidally forced flow however neither of them performs well when tidal and subtidal forces simultaneously drive the flows we have developed a novel obc that integrates the active obc in gan and allen 2005 and a flather type obc this new obc accommodates the concurrent tidal and subtidal tst forcing and the respective tidal or subtidal forcing at the open boundary of a limited area model this new tst obc treats the tidal component with a flather type obc and it separates subtidal barotropic and baroclinic components into local forced and global unforced components then an unforced orlanski type obc can be applied to the global part we applied the tst obc to all model variables to reduce dynamic inconsistence using the regional ocean modeling system we applied the tst obc to the shallow east china sea shelf where strong tidal and subtidal forces over complex topography govern the circulation our numerical experiments and analyses suggest that the tst obc was robust for both concurrent tidal subtidal forcing and solely tidal or subtidal forcing at the open boundary it reduced spurious energy reflection and overall it performed better than an orlanski type or flather type obc in reproducing realistic tidal and subtidal shelf circulation

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

the application of predictive modeling techniques to landslides induced by earthquakes the case study of the 26 september 1997 umbria marche earthquake italy abstract during september and october 1997 an earthquake sequence of moderate magnitude struck the umbria and marche regions central italy as a consequence of the most severe shocks several landslides were triggered on bedrock calcareous debris and sandy clay deposits the landslide inventory collected in the field and by aerial photo interpretation provided an opportunity to test the accuracy of existing predictive relations for landslide hazard zoning and to formulate new ones shallow soil slides and debris slides were selected to verify the prediction performance of the methods which are based on a simplified model geotechnique 15 1965 139 that calculate landslide displacements during cyclic seismic loading rock falls were modeled using a different approach to produce an empirical predictive rule for determining the probability of detachment of blocks when landslides occur along pre existing or newly formed failure surfaces the arias intensity and destructiveness potential are the strong ground motion parameters that best relate to displacements the predictive relation proposed for rock falls evaluates the probability of occurrence as a function of the slope angle and the peak ground acceleration pga

on the temporal variability of the transport through drake passage a recently obtained series of bottom pressure measurements from various positions in the drake passage dp has been used to estimate the transport variability of the antarctic circumpolar current acc under the assumption that the variability is predominantly barotropic and thus proportional to the north minus south pressure difference the standard deviations in derived transport range from 5 3 sv in 1993 to 8 9 sv in 1990 10 day filter 1 sv 106 m3 s 1 all values are less than the 10 sv 10 day filter obtained during the international southern ocean studies isos program at dp between the mid 1970s and early 1980s whitworth and peterson 1985 although some of this discrepancy is due to differences in procedure in dealing with gaps in the data our data suggest that the acc transport can be persistently less variable over several years than was previously thought in particular the isos data set contains two large amplitude changes in pressure difference over timescales less than 2 weeks while no similar events were observed in the more recent data although the more recent pressure gauges were deployed at different positions to those used in isos their reliability as indicators of acc transport changes has been established by examination of simultaneous pressure measurements within dp

gis modelling of slope stability in phewa tal watershed nepal abstract hazards are an inherent but dangerous and costly element of mountainous environments conventional maps of mountain hazards provide useful inventories of hazardous sites but provide little insight into the operation of the hazards furthermore this approach tends to rely heavily on subjective interpretation of the landscape which means that the results can not be replicated or transferred to other areas thus alternative approaches employing the quantitative capabilities of geographic information systems gis to model and predict slope stability are receiving increasing attention this paper reports on the use of a diverse gis database compiled primarily from existing maps and aerial photographs to construct a regional model of slope stability in phewa tal watershed nepal an integral part of the research was to explore an alternative approach to the commonly used grid cell approach by employing geomorphometrically significant terrain units the terrain units employed were created by generating line networks representing local maxima and minima extracted from elevation and curvature surfaces one of the chief benefits of applying gis technology in this research was the ability to georeference all of the attribute data to these terrain units in doing so it allowed the database to be exported into an external statistical package where the terrain units could be statistically explored as the basic analytical unit the application of a variety of statistical techniques resulted in logistic regression being selected as the most useful logistic regression successfully predicted terrain units as being either stable or unstable at a rate of approximately 90 concordance with a conventionally produced map of slope stability the statistical probabilities of terrain unit stability were imported back into the gis to produce a map of predicted slope stability that compared well with the conventional map of slope stability the findings of this research suggest that the use of geomorphometrically significant terrain units extracted from a digital elevation model dem are an efficient alternative to approaches using regular grid cells in particular the terrain units facilitated the use of logistic regression and significantly decreased the amount of computing costs finally this research also suggests that important information can be gathered from existing information sources such as maps aerial photographs and written documents thereby limiting the need for costly and time consuming field work at the reconnaissance level based on this latter finding other information sources such as satellite imagery should be examined

landslide susceptibility analysis and verification using the bayesian probability model the bayesian probability model using the weight of evidence method was applied to the task of evaluating landslide susceptibility using gis data the location chosen for the study was the janghung area in korea which suffered substantial landslide damage following heavy rain in 1998 using the location of the landslides as well as topographic factors such as soil forest and land use the weight of evidence method was used to calculate each factor s rating tests of conditional independence were performed for the selection of the factors allowing the large number of combinations of factors to be analyzed for each factor rating the contrast values w and w were overlaid for landslide susceptibility mapping the results of the analysis were verified using the observed landslide locations and among the combinations the slope aspect curvature soil material and wood types show the best results

a nested grid ocean model with application to the simulation of meanders and eddies in the norwegian coastal current oceanic flow phenomena vary in such large ranges of time and spatial scales that even with the fastest and largest computer to date one cannot at reasonable costs compute large scale circulation and at the same time resolve mesoscale features like fronts and or eddies yet these features are dynamically important and their inclusion may determine how well we can model the mean flow including the deep ocean circulation a two way interactive nested grid primitive equation model is developed here for coastal ocean applications notable features of the model are 1 nesting can be specified on any subregion of a coarse grid large domain and there can be more than one nest if required 2 the nested region can be hot started from earlier calculation results of the coarse grid region that is the code automatically by a change of an input flag generates topography wind forcing climatology currents density and other prognostic variables in the nest and steps forward in time 3 a time splitting integration with small timesteps in the nest and large timesteps in the coarse grid domain is used and 4 nested variables are driven by coarse grid solutions around the nest s boundaries where a flow relaxation scheme may be used and at the same time drive the coarse grid evolution through its averaged action in the overlapped region to demonstrate its robustness the model is applied in a february march 1988 real time simulation of meanders and eddies in the norwegian coastal current initialized from a 585 days quasi equilibrium calculation the simulation includes meteorological forcings inflows outflows across the open boundaries inflow of the north atlantic warm water in particular tides coastal and baltic discharges and wintertime hydrography for depths 500 m from march 20 to 31 the development of a meander between the froya and the halten banks is simulated the timing and location of the meander agree well with observed hydrography

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

spatial prediction of landslide susceptibility using an adaptive neuro fuzzy inference system combined with frequency ratio generalized additive model and support vector machine techniques abstract the spatial prediction of landslide susceptibility is an important prerequisite for the analysis of landslide hazards and risks in any area this research uses three data mining techniques such as an adaptive neuro fuzzy inference system combined with frequency ratio anfis fr a generalized additive model gam and a support vector machine svm for landslide susceptibility mapping in hanyuan county china in the first step in accordance with a review of the previous literature twelve conditioning factors including slope aspect altitude slope angle topographic wetness index twi plan curvature profile curvature distance to rivers distance to faults distance to roads land use normalized difference vegetation index ndvi and lithology were selected in the second step a collinearity test and correlation analysis between the conditioning factors and landslides were applied in the third step we used three advanced methods namely anfis fr gam and svm for landslide susceptibility modeling subsequently the results of their accuracy were validated using a receiver operating characteristic curve the results showed that all three models have good prediction capabilities while the svm model has the highest prediction rate of 0 875 followed by the anfis fr and gam models with prediction rates of 0 851 and 0 846 respectively thus the landslide susceptibility maps produced in the study area can be applied for management of hazards and risks in landslide prone hanyuan county

a method for producing digital probabilistic seismic landslide hazard maps abstract the 1994 northridge california earthquake is the first earthquake for which we have all of the data sets needed to conduct a rigorous regional analysis of seismic slope instability these data sets include 1 a comprehensive inventory of triggered landslides 2 about 200 strong motion records of the mainshock 3 1 24 000 scale geologic mapping of the region 4 extensive data on engineering properties of geologic units and 5 high resolution digital elevation models of the topography all of these data sets have been digitized and rasterized at 10 m grid spacing using arc info gis software on a unix computer combining these data sets in a dynamic model based on newmark s permanent deformation sliding block analysis yields estimates of coseismic landslide displacement in each grid cell from the northridge earthquake the modeled displacements are then compared with the digital inventory of landslides triggered by the northridge earthquake to construct a probability curve relating predicted displacement to probability of failure this probability function can be applied to predict and map the spatial variability in failure probability in any ground shaking conditions of interest we anticipate that this mapping procedure will be used to construct seismic landslide hazard maps that will assist in emergency preparedness planning and in making rational decisions regarding development and construction in areas susceptible to seismic slope failure

application of time series analysis and pso svm model in predicting the bazimen landslide in the three gorges reservoir china abstract the landslide displacement in the three gorges reservoir china experiences step like deformation that is influenced by rainfall and the periodic scheduling of the reservoir in view of the step like characteristic the particle swarm optimization and support vector machine pso svm coupling model based on the response of the induced factors was proposed to predict the landslide displacement the moving average method was adopted to divide the total displacement into trend term and periodic term the trend displacement was controlled by the geological conditions and predicted by polynomial function while the periodic displacement was under the combined control of the triggers and the evolution state of the landslide therefore the pso svm model based on the factors of the precipitation the variation range of the reservoir and the displacements of the prior periods was proposed to predict the periodic displacement the typical step like landslide in the three gorges reservoir which is known as the bazimen landslide was taken as a case study to verify the prediction results the values of the root mean square error and the mean absolute percentage error were 13 28 and 25 95 respectively the results showed that rainfall and reservoir water level were the dominant factors for the step like landslide deformation the evolution state of the landslide was also significant in reflecting the response relationship between the displacement and inducing factors in conclusion the proposed pso svm model can better represent the response relationship between the factors and the periodic displacement which made the predicted values of the total displacement fit with the measured values greatly

analysis of the chiufengershan landslide triggered by the 1999 chi chi earthquake in taiwan abstract a disastrous earthquake rocked taiwan on september 21 1999 with magnitude m l 7 3 and an epicenter near the small town of chi chi in central taiwan the chi chi earthquake triggered landslide on the dip slope at the chiufengershan in this study a review of the topography and geology of this area was followed by field investigations laboratory testing was applied to understand the geomaterial composing the slope then based on a series of limit equilibrium analyses the failure mechanism of this landslide and the risk of the residual slope were studied according to the stability analyses the pre quake slope is quite stable with factor of safety of 1 77 dry to 1 35 full groundwater level explaining why there is no written record of a landslide here for the past 100 years in contrast a back analysis shows that the chi chi earthquake induced dynamic loading is far more than the dip slope can sustain due in part to the short distance to the epicenter a monte carlo type probability analysis suggests that the residual slope is more dangerous than the pre quake slope and needs more attention

a comparative study of frequency ratio weights of evidence and logistic regression methods for landslide susceptibility mapping sultan mountains sw turkey abstract this study evaluated and compared landslide susceptibility maps produced with three different methods frequency ratio weights of evidence and logistic regression by using validation datasets the field surveys performed as part of this investigation mapped the locations of 90 landslides that had been identified in the sultan mountains of south western turkey the landslide influence parameters used for this study are geology relative permeability land use land cover precipitation elevation slope aspect total curvature plan curvature profile curvature wetness index stream power index sediment transportation capacity index distance to drainage distance to fault drainage density fault density and spring density maps the relationships between landslide distributions and these parameters were analysed using the three methods and the results of these methods were then used to calculate the landslide susceptibility of the entire study area the accuracy of the final landslide susceptibility maps was evaluated based on the landslides observed during the fieldwork and the accuracy of the models was evaluated by calculating each model s relative operating characteristic curve the predictive capability of each model was determined from the area under the relative operating characteristic curve and the areas under the curves obtained using the frequency ratio logistic regression and weights of evidence methods are 0 976 0 952 and 0 937 respectively these results indicate that the frequency ratio and weights of evidence models are relatively good estimators of landslide susceptibility in the study area specifically the results of the correlation analysis show a high correlation between the frequency ratio and weights of evidence results and the frequency ratio and logistic regression methods exhibit correlation coefficients of 0 771 and 0 727 respectively the frequency ratio model is simple and its input calculation and output processes are easily understood the interpretations of the susceptibility map reveal that geology slope steepness slope aspect and elevation played major roles in landslide occurrence and distribution in the sultan mountains the landslide susceptibility maps produced from this study could therefore assist planners and engineers during development and land use planning

a novel hybrid approach for landslide susceptibility mapping integrating analytical hierarchy process and normalized frequency ratio methods with the cloud model abstract landslides which could cause huge losses of lives or property damages result from several different environmental factors whose influences on landslides are very complex therefore it is essential to understand the relationships between these environmental factors and landslides thus the integration of the analytical hierarchy process ahp with the normalized frequency ratio nfr is evaluated for landslide susceptibility analyses however in addition to these complex relationships the randomness and fuzziness always affect landslide susceptibility mapping this study introduces the cloud model cm to improve the integrated ahp nfr method and proposes a novel hybrid ahp nfr cm method for landslide susceptibility analyses which can better address issues of the randomness and fuzziness firstly ten environmental parameters are selected as landslide impact factors and their values for all the landslides identified in the study area are obtained through the remote sensing rs and geographical information system gis technologies the ahp method is used to obtain the weight of each landslide impact factor and the nfr method is used to obtain the weight of each subclass in each landslide impact factor which can reflect the relationship between the landslide impact factor and landslide occurrence after applying an appropriate compositional operation between the weights of the landslide impact factors and the weights of the subclasses of the impact factors a landslide susceptibility index lsi for each grid divided via the attribution based spatial information multi grid method asimg can be computed to solve the inevitable issues of randomness and fuzziness in landslide susceptibility analyses a cloud model that uses three numerical features expectation entropy and hyper entropy to represent the intension of the concept is adopted to improve the methods of ahp and nfr the relative importance of two landslide impact factors is scaled with the cloud model rather than the saaty criteria pair wise comparison matrixes of landslide impact factors given by each expert are described by the normal cloud model and the floating cloud model is used to aggregate all experts judgments the weight of each landslide impact factor is also expressed with the cloud model rather than a certain value in improving the nfr the weight of each subclass of each landslide impact factor is expressed with the cloud model rather than a certain value in the improvement of the landslide susceptibility results the domain of landslide risk assessment results is also displayed with the cloud model instead of a series of definite intervals as the study area examined is large several grids would need to be divided meaning that it would take a considerable amount time to subject the entire study area to landslide susceptibility mapping thus we propose a new attribute based spatial information multi grid asimg division method and introduce grid computing technology to improve the calculation efficiency during the process finally the proposed hybrid ahp nfr cm asimg approach is validated and applied in the study area it s concluded that the new integration of ahp and nfr methods with the cloud model can consider both randomness and fuzziness and therefore can increase the robustness of landslide susceptibility analyses while the asimg technology can enhance the calculation efficiency in regional landslide susceptibility mapping

comparison of satellite and air photo based landslide susceptibility maps landslide susceptibility maps can be prepared in a variety of ways many geoscientists favour the use of an overlay model approach in which several map layers are combined by some arithmetic rules to determine the potential for sliding in an area or region the resulting susceptibility maps although based on a subjective weighting of relevant factors can often be of high accuracy and utility in order to obtain the relevant input data for this type of analysis remotely sensed data are often used to date susceptibility mapping just as the mapping of historic and individual landslides has tended to require higher resolution imagery this has somewhat limited the application of landslide susceptibility mapping while high resolution air photo or satellite imagery is superior to lower resolution imagery for the purpose of mapping of historic and individual landslides such higher levels of resolution may not be required for the development of landslide susceptibility maps in order to determine if medium resolution satellite imagery such as spot or aster could provide the needed data for landslide susceptibility mapping a comparison was undertaken of landslide susceptibility model output resulting from the use of stereo napp aerial photography versus the use of data obtained from stereo spot imagery the test area selected for this study consisted of two watersheds pena canyon and big rock canyon situated west of santa monica california usa along the pacific coast highway both watersheds have a long and well documented history of landslide activity and sufficient geologic variability and complexity to provide a good test site the specific overlay model used in this evaluation required input data consistent with the needs of many other models of this type the model output derived from the two different data sources and presented here in the form of susceptibility maps were virtually identical statistical and difference analysis confirmed that both methods of obtaining input data provide similar results and successfully identified landslide prone areas these results suggest that satellite imagery in this instance spot images could potentially be used in lieu of conventional air photos to evaluate landslide susceptibility in many situations especially in the case of remote locations and or developing countries this capability should result in substantial savings in terms of time financial resources and overall viability

a seismic landslide susceptibility rating of geologic units based on analysis of characteristics of landslides triggered by the 17 january 1994 northridge california earthquake abstract one of the most significant effects of the 17 january 1994 northridge california earthquake m 6 7 was the triggering of thousands of landslides over a broad area some of these landslides damaged and destroyed homes and other structures blocked roads disrupted pipelines and caused other serious damage analysis of the distribution and characteristics of these landslides is important in understanding what areas may be susceptible to landsliding in future earthquakes we analyzed the frequency distribution and geometries of triggered landslides in the santa susana 7 5 quadrangle an area of intense seismic landslide activity near the earthquake epicenter landslides occurred primarily in young late miocene through pleistocene uncemented or very weakly cemented sediment that has been repeatedly folded faulted and uplifted in the past 1 5 million years the most common types of landslide triggered by the earthquake were highly disrupted shallow falls and slides of rock and debris far less numerous were deeper more coherent slumps and block slides primarily occurring in more cohesive or competent materials the landslides in the santa susana quadrangle were divided into two samples single landslides 1502 and landslide complexes 60 which involved multiple coalescing failures of surficial material we described landslide morphologies by computing simple morphometric parameters area length width aspect ratio slope angle to quantify and rank the relative susceptibility of each geologic unit to seismic landsliding we calculated two indices 1 the susceptibility index which is the ratio given as a percentage of the area covered by landslide sources within a geologic unit to the total outcrop area of that unit and 2 the frequency index given in landslides per square kilometer ls km2 which is the total number of landslides within each geologic unit divided by the outcrop area of that unit susceptibility categories include very high 2 5 landslide area or 30 ls km2 high 1 0 2 5 landslide area or 10 30 ls km2 moderate 0 5 1 0 landslide area or 3 10 ls km2 and low

determination and application of the weights for landslide susceptibility mapping using an artificial neural network the purpose of this study is the development application and assessment of probability and artificial neural network methods for assessing landslide susceptibility in a chosen study area as the basic analysis tool a geographic information system gis was used for spatial data management and manipulation landslide locations and landslide related factors such as slope curvature soil texture soil drainage effective thickness wood type and wood diameter were used for analyzing landslide susceptibility a probability method was used for calculating the rating of the relative importance of each factor class to landslide occurrence for calculating the weight of the relative importance of each factor to landslide occurrence an artificial neural network method was developed using these methods the landslide susceptibility index lsi was calculated using the rating and weight and a landslide susceptibility map was produced using the index the results of the landslide susceptibility analysis with and without weights were confirmed from comparison with the landslide location data the comparison result with weighting was better than the results without weighting the calculated weight and rating can be used to landslide susceptibility mapping

assessment of landslide susceptibility on the natural terrain of lantau island hong kong steep terrain and the high frequency of tropical rainstorms make landslide occurrence on natural terrain a common phenomenon in hong kong for example more than 800 slope failures were triggered by a rainstorm in november 1993 on lantau island hong kong maps of recent landslides interpreted from aerial photographs in combination with a geographical information system were used to evaluate the frequency and distribution of landslides with particular reference to such physical parameters as lithology slope gradient slope aspect elevation vegetation cover and proximity to drainage line all of which are considered to be influential in the occurrence of landslides a stepwise logistic regression model was obtained between landslide susceptibility and the above mentioned physical parameters the study area has been classified into five classes of relative landslide susceptibility namely very low low moderate high and very high based on this methodology

spatial modelling of gully erosion in mazandaran province northern iran abstract gully erosion is one of the most severe environmental problems in large areas of iran the spatial distribution of gully erosion and its susceptibility zonation was studied using different bivariate statistical models such as frequency ratio fr weights of evidence wofe and index of entropy iofe for this purpose 109 gully erosion locations were identified and divided into training 70 and validating 30 datasets effective factors including elevation slope aspect slope degree slope length ls topographical wetness index twi plan curvature profile curvature land use lithology distance from river drainage density and distance from road were selected to develop maps of gully erosion susceptibility the spatial relationship between gully erosion and each effective factor was calculated by the mentioned models the relative operating characteristic roc curve was implemented for evaluating the accuracy of the applied predictive models results indicated that frequency ratio model had better performance 80 4 than the weight of evidence 79 5 and index of entropy 79 models the produced gully erosion susceptibility maps can be helpful to make decisions for soil and water planning and management and finally sustainable development in the valasht watershed

validation of an artificial neural network model for landslide susceptibility mapping the aim of this study was to validate an artificial neural network model at youngin janghung and boeun korea using the geographic information system gis the factors that influence landslide occurrence such as the slope aspect curvature and geomorphology of topography the type material drainage and effective thickness of soil the type diameter age and density of forest distance from lineament and land cover were either calculated or extracted from the spatial database and landsat tm satellite images landslide susceptibility was analyzed using the landslide occurrence factors provided by the artificial neural network model the landslide susceptibility analysis results were validated and cross validated using the landslide locations as study areas for this purpose weights for each study area were calculated by the artificial neural network model among the nine cases the best accuracy 81 36 was obtained in the case of the boeun based janghung weight whereas the janghung based youngin weight showed the worst accuracy 71 72

gis based landslide susceptibility mapping for a part of the north anatolian fault zone between resadiye and koyulhisar turkey abstract in the present study landslide susceptibility assessment for a part of the north anatolian fault zone between resadiye and koyulhisar townships has been determined using index of entropy ioe and frequency ratio fr models within geographical information system the landslide inventory map has been created in the study area altogether 91 landslides were mapped and 63 69 were randomly selected for modelling with the remainder 28 31 used for validating the models the landslide conditioning factors including slope degree aspect elevation distance to faults distance to streams distance to road were selected subsequently landslide susceptibility maps were produced using frequency ratio and index of entropy models for verification the receiver operating characteristic roc curves were drawn and the areas under the curve auc were calculated the verification results showed that fr model auc 75 71 provided slightly better predictions than the ioe auc 75 43 model according to the fr about 32 54 of the study area is located within high to very high susceptibility classes of landslides the interpretation of the susceptibility map indicates that distance to streams distance to road and distance to fault play major roles in landslide occurrence and distribution in the study area the landslide susceptibility maps like the one produced in this study should provide a valuable tool for the use of planners and engineers for reorganizing or planning new road and domestic constructions

the use of predictive modeling techniques for optimal exploitation of spatial databases a case study in landslide hazard mapping with expert system like methods a case study is presented in which different probabilistic prediction models bayesian probability fuzzy logic and or sum product gamma operations and certainty factors are used to produce landslide hazard maps for a hilly and mountainous region in the northern apennines italy seven data layers are exploited to detect most vulnerable areas lithology distance from the geological lineaments annual rainfall amount land cover type topographic slope and aspect and the distance from hydrographic network segments the results of the different predictions are compared using the prediction rate index and critically discussed to evaluate the possibility of using readily available databases for land planning

modeling landslide susceptibility in data scarce environments using optimized data mining and statistical methods abstract this study evaluated the generalizability of five models to select a suitable approach for landslide susceptibility modeling in data scarce environments in total 418 landslide inventories and 18 landslide conditioning factors were analyzed multicollinearity and factor optimization were investigated before data modeling and two experiments were then conducted in each experiment five susceptibility maps were produced based on support vector machine svm random forest rf weight of evidence woe ridge regression rid r and robust regression rr models the highest accuracy auc 0 85 was achieved with the svm model when either the full or limited landslide inventories were used furthermore the rf and woe models were severely affected when less landslide samples were used for training the other models were affected slightly when the training samples were limited

landslide susceptibility mapping at central zab basin iran a comparison between analytical hierarchy process frequency ratio and logistic regression models abstract the purpose of this study is to compare the landslide susceptibility mapping models of logistic regression lr analytical hierarchy process ahp and frequency ratio fr applied in the central zab basin west azerbaijan iran eight factors were used for landslide susceptibility mapping including slope aspect land cover precipitation lithology and the distance to roads drainage and faults that affect the occurrence of landslides to get more precision speed and facility in our analysis all descriptive and spatial information was entered into gis system satellite images landsat etm and spot 5 are also used to prepare for land use and landslide inventory mapping respectively landslide events as used as dependant variable and data layers as independent variable making use of the correlation between these two variables in landslide susceptibility the three models are validated using the relative landslide density index r index and the receiver operating characteristic roc curves the predictive capability of each model was determined from the area under the relative operating characteristic curve and the areas under the curves obtained using the lr ahp and fr methods are 0 8941 0 8115 and 0 8634 respectively these results indicate that the lr and fr models are relatively good estimators of landslide susceptibility in the study area the interpretations of the susceptibility map reveal that precipitation lithology and slope played major roles in landslide occurrence and distribution in the central zab basin in general all three models were reasonably accurate the resultant maps would be useful for regional spatial planning as well as for land cover planning

entropy theory integrated information model for the assessment of geothermal potential a case study of tengchong county southwest china geothermal energy remains a largely undeveloped natural resource because of the high risk associated with its development an accurate prediction model for easy identification of potential regions can help to lower the risk and cost associated with development in this study geothermal potential regions were identified through the relationship between geothermal emergencies and their controlling factors in tengchong county china publicly available databases for this analysis including epicenters active faults bouguer gravity landsat7 enhanced thematic mapper plus images the magnetic data and digital elevation model data were extracted as the b value map distance to faults map distance to main grabens map land surface temperature map magnetic anomaly map and distance to rivers map respectively based on the platforms within geographic information system an entropy theory integrated information model was established to evaluate the geothermal potential sites within the region moreover factor analysis method was applied to test the conditional independence between the map pairs before modeling application the results of the weighted information model show that the model shows perfect performance in discovering potential geothermal regions in the final maps undeveloped or unexploited geothermal regions can be observed along the mingguang river and nu river undeniably these models will help to find undiscovered geothermal regions with limited geological information publically available

landslide databases for climate change detection and attribution abstract a systematic inventory of landslide events over regional spatial scales and through time is required for investigating changes in landslide frequency along side changes in landslide triggers this paper describes the methods used to compile a european wide landslide inventory and some of the methodological and practical obstacles that inhibit better use and development of such inventories we argue that these methods can be used more widely to provide a comprehensive picture of landslide populations and to further enrich our understanding of the impact of climate change and other drivers on landslide frequency and magnitude

two way interactive nesting of primitive equation ocean models with topography abstract two way interactive nesting of primitive equation ocean models is investigated with special attention to the problems encountered when oceanic features for example fronts intersect the boundaries between the models and also when topography is present the model has two interacting components the coarse and fine grid regions the fine grid region can have a finer resolution both in the horizontal and in the vertical than the coarse grid model allowing refinement of topographic features in the vertical as well as the horizontal although a model with nesting only in the horizontal is considered first to clarify the effects of the lateral boundaries an adaptation of the method of spall and holland is used the interaction is two way the coarse grid fields are interpolated to provide boundary conditions for the fine grid region and the variables on the fine grid are suitably averaged onto the coarse grid in order to drive the coarse grid model nested calculations with 3 1 grid ratios are p

assessment of landslide susceptibility for a landslide prone area north of yenice nw turkey by fuzzy approach regional landslide susceptibility assessments pose complex problems to solve these problems numerous approaches such as statistical analysis geotechnical engineering approach geomorphologic approach and fuzzy logic have been employed however all the available methods for regional landslide susceptibility assessments have some uncertainties due to a lack of knowledge and variability minimizing these uncertainties provides realistic approaches use of the fuzzy logic approach to produce a landslide susceptibility map of a landslide prone area in nw turkey is the main purpose of the present study for this purpose the study includes five main stages these being the preparation of a landslide inventory of the study area the application of factor analysis the extraction of fuzzy if then rules the use of a geographical information system and the control of the reliability of the resulting landslide susceptibility map slope angle slope aspect land use weathering depth water conditions and topographical elevation were considered as landslide conditioning factors for the study area a total of 23 if then rules was extracted from the field data employing these rules fuzzified index maps representing each parameter were obtained finally combining these maps the landslide susceptibility map of the area was prepared when compared with the landslide susceptibility map the landslides identified in the area were found to be located in the very high and high susceptibility zones as far as the performance of the fuzzy approach for processing is concerned the images appear to be quite satisfactory the zones determined on the map being zones of relative susceptibility

landslide susceptibility mapping by correlation between topography and geological structure the janghung area korea the purpose of this study is to develop and apply the technique for landslide susceptibility analysis using geological structure in a geographic information system gis in the study area the janghung area of korea landslide locations were detected from indian remote sensing irs satellite images by change detection where the geological structure of foliation was surveyed and analysed the landslide occurrence factors location of landslide geological structure and topography were constructed into a spatial database then strike and dip of the foliation and the aspect and slope of the topography were compared and the results which were verified using landslide location data show that foliation of gneiss has a geometrical relation to the joint or fault that leads to a landslide using the geometrical relations the landslide susceptibility was assessed and verified the verification results showed satisfactory agreement between the susceptibility map and the landslide location data

luminescence dating of holocene geomorphic activity on ammassalik island se greenland abstract a geomorphological investigation of nival aeolian and littoral landforms based on sedimentological and stratigraphical analyses combined with eight optically stimulated luminescence osl and two 14 c accelerator mass spectrometry ams dates are presented from the mittivakkat area western ammassalik island se greenland as the sediments are liable to annual freezing the modern average annual water content has been modelled and used in the calculation of the luminescence ages the osl technique gaves ages as young as 500 years and is considered useful for dating the relatively young sediments of this arctic environment by combining the results of the investigations of the individual landforms a first attempt towards a reconstruction of the geoenvironment primarily during the late holocene becomes possible enhanced geomorphological activity during the little ice age is evidenced by increased snowdrift and aeolian activity from about 900 years ago the prevalent wind direction has been from n and ne since at least about 2800 300 years ago as nivation activity has taken place at least since then and avalanche slopes have been active since about 3900 560 years ago sediments in the mittivakkat delta have been deposited at least since 1300 400 years ago indicating sea level to have been close to the present level by that time an aeolian sand sheet started to accumulate around 500 40 years ago on the beach south of the mittivakkat delta providing further evidence for a sea level close to the present two dates for sediment from raised littoral terraces at 10 and 40 m asl clearly postdate general sea level activity at these levels average late holocene terrestrial sedimentation rates from 0 06 to 1 69 mm y 1 have been determined for the different landforms

statistical analysis of landslide susceptibility at yongin korea the aim of this study is to evaluate the susceptibility of landslides at yongin korea using a geographic information system gis landslide locations were identified in the yongin area from interpretation of aerial photographs field surveys and maps of the topography soil type timber cover and geology these data were collected and constructed into a spatial database using gis the factors that influence landslide occurrence such as slope aspect and curvature of topography were calculated from the topographic database texture material drainage and effective soil thickness were extracted from the soil database and type age diameter and density of timber were extracted from the forest database lithology was extracted from the geological database and land use was classified from the landsat tm satellite image landslide susceptibility was analyzed using the landslide occurrence factors by probability and logistic regression methods the results of the analysis were verified using the landslide location data the validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide location the gis was used to analyze the vast amount of data efficiently and statistical programs were used to maintain specificity and accuracy the results can be used to reduce associated hazards and to plan land use and construction

discontinuity controlled probabilistic slope failure risk maps of the altindag settlement region in turkey the evaluation of potential rock slope problems using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in jointed rock media in conventional stereoprojection techniques for the assessment of possible rock slope failures the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used other possible joint orientations which may be encountered in the rock media are ignored although they belong to the group of joint peak orientations in this study nearly vertical jointed andesites cropped out at the altindag settlement region in ankara were studied in order to evaluate the relevance of this ignored discontinuity orientation data on slope stability as a result probabilistic risk maps for planar toppling and wedge failures were produced using the kinematic rules and digital elevation model of the study area the comparison of the distribution of the actual failures in the area and the probabilistic risk maps prepared for the study area revealed that all of the identified failures are found to be located in the higher risk zones on the probabilistic risk maps

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

spatial probabilistic modeling of slope failure using an integrated gis monte carlo simulation approach spatial probabilistic modeling of slope failure using a combined geographic information system gis infinite slope stability model and monte carlo simulation approach is proposed and applied in the landslide prone area of sasebo city southern japan a digital elevation model dem for the study area has been created at a scale of 1 2500 calculated results of slope angle and slope aspect derived from the dem are discussed through the spatial interpolation of the identified stream network the thickness distribution of the colluvium above tertiary strata is determined with precision finally by integrating an infinite slope stability model and monte carlo simulation with gis and applying spatial processing a slope failure probability distribution map is obtained for the case of both low and high water levels

landslide characteristics and slope instability modeling using gis lantau island hong kong steep terrain and high a frequency of tropical rainstorms make landslide occurrence on natural terrain a common phenomenon in hong kong this paper reports on the use of a geographical information systems gis database compiled primarily from existing digital maps and aerial photographs to describe the physical characteristics of landslides and the statistical relations of landslide frequency with the physical parameters contributing to the initiation of landslides on lantau island in hong kong the horizontal travel length and the angle of reach defined as the angle of the line connecting the head of the landslide source to the distal margin of the displaced mass are used to describe runout behavior of landslide mass for all landslides studied the horizontal travel length of landslide mass ranges from 5 to 785 m with a mean value of 43 m and the average angle of reach is 27 7 this gis database is then used to obtain a logistic multiple regression model for predicting slope instability it is indicated that slope gradient lithology elevation slope aspect and land use are statistically significant in predicting slope instability while slope morphology and proximity to drainage lines are not important and thus excluded from the model this model is then imported back into the gis to produce a map of predicted slope instability the results of this study demonstrate that slope instability can be effectively modeled by using gis technology and logistic multiple regression analysis