gis analysis to assess landslide susceptibility in a fluvial basin of nw sicily italy abstract landslide hazard assessment effected by means of geostatistical methods is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors frequently such analyses are based on landslide inventories in which each record represents the entire unstable area and is managed as a single instability landform in this research landslide susceptibility is evaluated through the study of a variety of instability landforms landslides scarps and areas uphill from crown the instability factors selected were bedrock lithology steepness topographic wetness index and stream power index the instability landform densities computed for all the factors which were arranged in unique condition unit allowed us to derive a total of three prediction images for each landslide typology the role of the instability factors and the effects generated by the use of different landforms were analyzed by means of a bivariate analysis of the relationships between factors and landslide density b predictive power validations of the prediction images based on a random partition strategy the test area was the iato river basin north western sicily whose slopes are moderately involved in flow and rotational slide landslides 219 and 28 respectively the area is mainly made up of the following complexes numidian flysch clays 19 1 terravecchia sandy clays 5 1 terravecchia clayey sands 3 0 3 and san cipirello marly clays 9 0 the steepness parameter shows the highest landslide density in the 11 19 class for both the typologies 8 1 even if the density distributions for rotational slides are right asymmetric and right shifted we obtained significant differences in shape when we used different instability landforms unlike scarps and areas uphill from crowns landslide areas produce left asymmetric and left shifted density distributions for both the typologies as far as the topographic wetness index is concerned much more pronounced differences were detected among the instability landforms of rotational slides in contrast the flow landslides produce normal like density distributions the latter and the rotational slide landslide areas produce the highest density values in the class 5 5 6 7 despite an abrupt decreasing trend starting from the first class 3 2 4 4 which is generated by the density values of the rotational slide scarps and areas uphill from crowns the stream power index at the foot of the slopes which was automatically derived using a gis procedure shows a positive correlation with the landslide densities marked by the maximum classes 4 8 6 0 for flows and 6 0 7 2 for rotational slides the validation procedure results confirmed that the choice of instability landform influences the results of the susceptibility analysis furthermore the validation procedure indicates that a the predictive models are generally satisfactory b scarps and zones uphill from crown areas are the most diagnostically unstable landforms for flow and rotational slide landslides respectively

interstitial water studies of late quaternary eastern mediterranean sediments with emphasis on early diagenetic reactions and evaporitic salt influences interstitial waters of five piston cores from the eastern mediterranean were recovered by shipboard squeezing and analyzed for their major elements additionally organic carbon caco3 and hcl extractable mg were determined in the sediments from these cores three cores contain sapropels which are considered to be the sedimentary expression of anoxic periods during the quaternary the ph in the interstitial waters extracted from the sapropels is significantly lower than the ph of the interstitial waters from the surrounding sediment it is suggested that the low ph in sapropel interstitial waters is induced by bacterial activity other dissolved elements are not influenced by these sapropel layers core t83 46 taken in the hypersaline anoxic tyro basin shows a strong downward so4 decrease accompanied by a strong nh4 increase the interstitial water chemistry of the tyro basin sediment is attributed to selective leaching of evaporitic salt first halite dissolution later followed by gypsum dissolution the interstitial water chemistry of core t83 45 taken in the adjacent kretheus basin is dominated by diffusive processes which became important after oxic conditions returned in this formerly anoxic hypersaline basin

the chemical composition and origin of the tyro brine eastern mediterranean a tentative model abstract the tyro basin located within the strabo trench eastern mediterranean is an anoxic brine filled depression at a depth of 3300 m the chemical composition of the brine is similar to that of the orca basin although it is somewhat more concentrated and has a higher so 4 content its composition is most likely determined by an outcropping messinian evaporitic sequence from gypsum up to soluble salts the br content of the halite is estimated from the brine composition and the result 200 ppm is in fair agreement with the data from dsdp site 374 from the ionian basin 118 218 ppm

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

exhumation of messinian evaporites in the deep sea and creation of deep anoxic brine filled collapsed basins abstract the first part of the paper summarizes some basic concepts concerning a the distribution of messinian evaporites in the deepest parts of the mediterranean sea and b the mediterranean ridge accretionary wedge and its peculiar characteristics deriving from the presence of a substantial evaporitic body in the deforming sedimentary prism then five brine filled anoxic collapsed basins tyro bannock urania atalante and discovery discovered from 1983 to 1994 are presented and discussed in their physiographic geologic hydrologic and geochemical characters high density brines deriving from submarine dissolution of outcropping or subcropping evaporites accumulate at the bottom of collapsed basins if they are not swept away by submarine currents the interface separating normal sea water from high density brines is sharp with a density contrast of about 20 and lies at 3200 3500 m below sea level strong bacterial activity is developing at the interface and living bacteria have been recovered from the anoxic salty brines thickness of the brines may be up to 500 m thermal stratification has been observed in three brine lakes exhumation and dissolution of messinian evaporites in the mediterranean ridge occur in different tectonic settings pull apart basin tyro subducting seamount close to the outer deformation front bannock basin top of a backstop urania atalante and discovery basins chemistry of the brines is strongly variable and suggests dissolution of different layers or levels of the messinian suite discovery brines are the saltiest ever recorded in natural environment their saturation in mg chloride bischofite the end product of sea water evaporation suggests that the deepest parts of the eastern mediterranean were close to dryness at the end of the salinity crisis strongly supporting the deep basin desiccation model

new findings of bronze age homogenites in the ionian sea geodynamic implications for the mediterranean abstract holocene homogenites similar in character and stratigraphic position to those previously recorded in the ionian basin and related to the gigantic tsunami originating from santorini bronze age eruption are described from a core transect crossing the deformation front of the mediterranean ridge east of victor hensen seahill investigations on grain sizes and carbonate content carried out on three cores from three different areas of the ionian basin encompassing the bronze age homogenite revealed important similarities and some differences the most obvious difference concerns the carbonate content which is minimum at the base of the unit in a core close to the messina abyssal plain whereas it is maximum in cores from the western mediterranean and calabrian ridges characterized by the typical cobblestone topography a terrigenous versus pelagic nature of the components is documented and a distal versus local provenance is inferred homogenites are critically compared with unifites a type of re sediment recently described from the eastern mediterranean comparison includes in particular a source and sediment transport and b triggering mechanism a substantial difference exists between the sedimentation patterns of the ionian and levantine basins seaward of the calabrian and hellenic arcs in the latest quaternary and the difference contains a clear geodynamic message sedimentation rates increase from the late pleistocene to the holocene in the ionian basin whereas they decrease in the levantine basin the glacio eustatic signal is well expressed in the levantine basin where the source areas are situated consistently in the south or on a passive type aseismic continental margin north african margin in the ionian basin on the contrary the glacioeustatic signal is totally obscured by the strong tectonic signal from the active northern continental margin of the mediterranean

discovery of an anoxic basin within the strabo trench eastern mediterranean we report here the discovery of a basin which we call the tyro basin in the eastern mediterranean in which anoxic conditions exist and organic rich sediments are accumulating bottom water samples show extremely high salt concentrations a horizontal midwater sound reflector about 70 m above the basin floor was observed in a seismic reflection profile across the basin from shipboard observations we conclude that dissolution of messinian evaporites exposed by faulting in the sides of the basin causes stagnant bottom conditions this basin provides an opportunity to test some of the hypotheses concerning the formation of sapropels present in cores collected from the same area cores taken in an adjacent similar basin for which we propose the name kretheus basin indicate a recent change from anoxic to oxygenated conditions which was probably caused by tectonic activity associated with the strabo trench

late quaternary sedimentation in the tyro and kretheus basins southeast of crete abstract this paper summarizes micropaleontologic foraminifera calcareous nannoplankton radiolaria pteropods and pollen grains and sedimentologic piston core data from the eastern mediterranean tyro and kretheus basins 14 c datings indicate a holocene age for the tyro basin cores the latter show anoxic bottom conditions throughout while the kretheus basin core indicates anoxic conditions prior to 3000 years ago and oxic conditions after that time resedimentation through slumps turbidity currents and from suspension resulted in high sediment accumulation rates in both basins reworking in the tyro basin predominantly originated from the basin flanks while the presence of common to abundant metamorphic clastics in the kretheus basin points to a more distant source the minoan eruption of santorini ca 3350 yrs b p which is supposed to have caused a gigantic tsunami is linked to the presence of turbidites and a thick homogenite in the tyro basin the same event may be responsible for the initiation of oxic conditions in the kretheus basin

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

threshold behavior of karst aquifers the example of the lurbach karst system austria threshold behavior in hydrological systems generally involves a qualitative change of a single process the system response or the functioning of the system different types of thresholds and their underlying controls are examined using the example of the lurbach karst system austria this karst system receives allogenic recharge from the sinking stream lurbach which under low flow conditions only resurges at the hammerbach spring yet under medium to high flow conditions an overflow toward another spring the schmelzbach outlet occurs thresholds in physicochemical spring responses and their underlying controls are identified from the analysis of heat and solute transport processes in karst conduits applying this concept to the hammerbach spring suggests that the threshold controlling the response of the spring water temperature was changed in the time period from 2006 to 2009 relative to the years before at the same time changes are observed in the behavior of the spring hydrograph and the discharge threshold at which the overflow to the schmelzbach system is activated all of these observations can be consistently explained by a decreased diameter of the conduit pathways within the indicated time period presumably caused by the redistribution of sediments due to a flood event in 2005 thus thresholds in the physicochemical spring response were successfully employed to support the identification of a change in the functioning of the lurbach karst system which occurred possibly because a threshold related to the sediment transport within the karst conduits was crossed

morphometric analysis of three dimensional networks of karst conduits the main idiosyncrasy of a typical karst system is the presence of a three dimensional network of conduits behaving as drains in the system and being responsible of both the quick response of karst springs to rainfall events and the complex distribution of solutes in the system a morphometric analysis of the three dimensional geometry of conduits provides quantitative measures that can be used in a range of applications these morphometric parameters can be used as descriptors of the underground geomorphology they provide information on speleogenesis processes they can be correlated with karst denudation ratios they can be used to control the simulation of realistic stochastic karst networks of conduits and they can be correlated with hydrogeologic behaviour of the karst system the main purpose of this paper is to define describe and illustrate a range of morphometric indexes and morphometric functions that can be calculated nowadays because the availability of three dimensional topographies provided by speleological work and the availability of the computational and graphical power provided by modern computers some of the morphometric parameters describe the existence of preferential directions of karstification others describe the kartification along the vertical and the possible presence of inception horizons other indexes describe the shape complexity of the karstic network whilst other indexes describe spatial variability of the conduit geometry and other parameters give account of the connectivity of the three dimensional network the morphometric analysis is illustrated with a three dimensional karstic network in southern france

the water on a small karst island the island of korcula croatia as an example the island of korcula which has an area of 271 47 km2 is located along the north eastern coast of the adriatic sea due to the mediterranean climate size and karst geology its water resources are very scarce this paper describes the natural features of the island air temperature precipitation geology hydrogeology and groundwater which are important for the water appearance and its distribution in time and space the water supply of the island has been managed in the following ways through a pipeline from the mainland by drawing groundwater and by rain harvesting tourism causes high seasonal water needs which are barely met by the existing water supply system therefore present water resource management on the island must be improved the paper also presents mathematical programming scheme to get optimal costs and benefits of water exploitation on the island besides economic aspect linear programming is applied to social and ecological objectives as well this study suggests that island s water management should be primarily based on wisely using its proper water resources

modelling karst geomorphology on different time scales abstract the evolution and flow in a karst aquifer is studied with numerical simulations based on the karst model karst aquifer simulation tool the aquifer consists of a three dimensional interconnected network of conduits representing fractures in the rock and a porous rock matrix representing the finer fissured system in the rock flow through the aquifer can be driven by both diffuse recharge from precipitation and localised sinking streams and the aquifer drains towards a large karst resurgence representing the base level superimposed onto the karst aquifer is a landscape which can evolve with time by small scale diffusive processes large scale river erosion and karst denudation fractures in the aquifer are enlarged with time by chemical dissolution enhancing the secondary porosity of the karst aquifer the enlargement of fractures results in a dramatic increase of the aquifer conductivity over several orders of magnitude and a change of flow patterns from an initially pore controlled to a heterogeneous fracture controlled aquifer during the evolution the water table is falling from an initially high position close to the land surface to a lower level coinciding with the actual base level two model scenarios are studied to elucidate the karst aquifer evolution in three dimensions the evolution models are then complemented by event type spring discharge modelling which can be used as a predictive tool for karst spring discharge and contaminant transport

gis based landslide susceptibility mapping using analytical hierarchy process and bivariate statistics in ardesen turkey comparisons of results and confirmations abstract the ardesen area is prone to landslides because of the climate conditions geologic and geomorphologic characteristics of the region as in previous years in 2001 due to heavy rainfall there were many landslides resulting in damage and human casualties there is still a great danger of further landslides in the region therefore it is vitally important to prepare a landslide susceptibility map of the region in this study the analytical hierarchy process ahp the statistical index wi and weighting factor wf methods were used to produce and later compare three susceptibility maps for this purpose thematic layers including landslide inventory lithology weathering slope aspect land cover distance to stream drainage density and distance to road were used in this study area 98 of landslides occurred in highly or completely weathered units lithology weathering land cover and slope data layers were found to be important factors in the study area to confirm the practicality of the three susceptibility maps were compared with a landslide activity map containing 16 active landslide zones the outcome was that the active landslide zones do not completely fit into the high and very high susceptibility classes but 81 3 of these landslide zones fall into the high and very high susceptibility zones of the ahp method while this is 62 5 in the case of wi method and 68 8 with the wf method in spite of the results obtained in this study the development of a susceptibility map is usually determined by the needs and available resources the results showed that the ahp method gave a more realistic picture of the actual distribution of landslide susceptibility than the wi and wf methods

karstic uvala revisited toward a redefinition of the term abstract uvalas are a particular type of karst closed depression while other types of closed depression dolines and poljes are regularly listed and relatively well defined in overviews of karst surface morphology uvalas are either excluded or their vague identification is stressed the leading idea of this paper is to obtain a clearer meaning of the term uvala and prevent its abandonment from karstology and general geomorphology within the study 43 examples of uvalas have been selected the studied uvalas are located in the dinaric karst and karst of the carpatho balkanides all the case examples have been digitally processed in the same way creation of high resolution digital elevation models enabled quantification of morphometric parameters generation of inclination maps and cross sections as well as application of statistical analyses formation of the geographical information system of the studied uvalas was done using raster based and vector based gis software packages in 12 studied uvalas detailed structural geological mapping has been carried out which revealed dominant development of uvalas along regional scale tectonically broken zones a revised definition of the term uvala is suggested leaving the opportunity for further discussion

artificial neural networks applied to landslide susceptibility assessment abstract landslide hazard mapping is often performed through the identification and analysis of hillslope instability factors usually managed as thematic data within geographic information systems gis in heuristic approaches these factors are rated by the attribution of scores based on the assumed role played by each of them in controlling the development of a sliding process other more refined methods based on the principle that the present and the past are keys to the future have also been developed thus allowing less subjective analyses in which landslide susceptibility is assessed by statistical relationships between past landslide events and hillslope instability factors the objective of this research is to define a method with the ability to forecast landslide susceptibility through the application of artificial neural networks anns the riomaggiore catchment a subwatershed of the reno river basin located in the northern apennines italy was chosen as an ideal test site as it is representative of many of the geomorphological settings within this region in the present application two different anns used in classification problems were set up and applied one belonging to the category of multi layered perceptron mlp and the other to the probabilistic neural network pnn family the hillslope factors that have been taken into account in the analysis were the following a lithology b slope angle c profile curvature d land cover and e upslope contributing area these factors have been classified on nominal scales and their intersection allowed 3342 homogeneous domains unique condition unit ucu to be singled out which correspond to the terrain units utilized in this analysis the model vector used to train the anns is a subset of that derived from the production of unique condition units and consists of 3342 records organized in input and output variable vectors in particular the hillslope factors once classified on nominal scales as binary numbers represent the 19 input variables while the presence absence of a landslide in a given terrain unit is assumed to be the output variable the comparison between the most up to date landslide inventory of the riomaggiore catchment and the hazardous areas as predicted by the anns showed satisfactory results with a slight preference for the mlp for this reason this is an encouraging preliminary approach towards a systematic introduction of ann based statistical methods in landslide hazard assessment and mapping

gis based regional landslide susceptibility mapping a case study in southern california landslides threaten lives and property throughout the united states causing in excess of 2 billion in damages and 25 50 deaths annually in regions subjected to urban expansion caused by population growth and or increased storm intensities caused by changing climate patterns the economic and society costs of landslides will continue to rise using a geographic information system gis this paper develops and implements a multivariate statistical approach for mapping landslide susceptibility the presented susceptibility maps are intended to help in the design of hazard mitigation and land development policies at regional scales the paper presents a a gis based multivariate statistical approach for mapping landslide susceptibility b several dimensionless landslide susceptibility indexes developed to quantify and weight the influence of individual categories for given potential risk factors on landslides and c a case study in southern california which uses 11 111 seismic landslide scars collected from previous efforts and 5389 landslide scars newly digitized from local geologic maps in the case study seven potential risk factors were selected to map landslide susceptibility ground slope and event precipitation were the most important factors followed by land cover surface curvature proximity to fault elevation and proximity to coastline the developed landslide susceptibility maps show that areas classified as having high or very high susceptibilities contained 71 of the digitized landslide scars and 90 of the seismic landslide scars while only occupying 26 of the total study area these areas mostly have ground slopes higher than 46 and 2 year 6 hour precipitation greater than 51 mm only 12 of digitized landslides and less than 1 of recorded seismic landslides were located in areas classified as low or very low susceptibility while occupying 42 of the total study region these areas mostly have slopes less than 27 and 2 year 6 hour precipitation less than 41 mm copyright 2007 john wiley sons ltd

analytic network process model for landslide hazard zonation various controlling factors such as lithology slope angle slope aspect landuse channel proximity etc are generally considered for the landslide hazard assessment although outer dependence of these parameters to a landslide is inevitably taken into account inter dependence among the factors is seldom addressed analytic network process anp is the multi criteria decision making mcdm tool which takes into account such a complex relationship among parameters in this research an anp model for landslide susceptibility is proposed priority weights for each parameter controlling the landslide were determined and a hazard map was prepared of an area in a fragile mountainous terrain in the eastern part of nepal the data used in the example were derived from published sources aerial photographs and a topographic map however the procedures developed can readily incorporate additional information from more detailed investigations

late quaternary planktonic foraminiferal biostratrigraphy strait of sicily mediterranean sea abstract the development of a detailed planktonic foraminiferal biostratigraphy for the late quaternary latest 180 000 years has allowed the dating and correlation of sediments from the strait of sicily principal component analysis of the assemblages has extracted a climatic history similar to that based upon oxygen isotopic oscillations intercore correlations are supported by tephrochronology and sapropel layer stratigraphy identification of termination ia and ib in several high sedimentation rate cores indicates that the mediterranean sea experienced a two stage warming during the last deglaciation cores collected between water depths of 200 and 600 m contain an erosional hiatus near their tops reflecting an increase in the levantine intermediate water flow sometime since 25 000 years b p and as recently as 7000 years b p during deposition of the youngest sapropel layer a distinct and unusual planktonic foraminiferal succession is associated with sapropel layers this begins in a protosapropel layer immediately beneath a sapropel horizon and continues upwards to the immediately overlying oxidized layer

ground water behaviour in karst example of the ombla spring croatia abstract the hydro electric power plant hepp which will exclusively use water from a karst underground storage basin will be built in the vicinity of the abundant karst spring ombla in croatia this paper presents the results obtained by hydrogeologic hydrologic and hydraulic investigations related to the principles of ground water circulation in the karst the analyses included the determination of the effective porosity ne of the karst aquifer and the definition of the volume of large conduits and small fractures in the karst which form the aquifer volume the position and dimensions of large karst conduits have also been defined it was established that in three small springs zaton zavrelje and slavljan water overflows from the ombla spring in periods of high ground water levels it was also discovered that at certain periods the dupuit expression for steady state flow in an unconfined aquifer can be used in accordance with this it was possible to determine the values of hydraulic conductivity k in m s 1 for the ombla aquifer they range from 2 10 3 to 5 10 3 m s 1 and are inversely proportional to the ombla spring discharge continuous measurements of the ground water level by several piezometers located in the karst hinterland of the ombla spring and simultaneous measurement of the discharge made it possible to define discharge curves of the ombla spring dependent upon the ground water levels at various locations characteristic features of the discharge curves made the identification of the position and dimensions of the main karst conduits possible

geomorphological and historical data in assessing landslide hazard traditionally earth scientists assess landslide occurrence on the basis of geomorphological investigations carried out through aerial photograph interpretation and eldwork conversely local administrators primarily evaluate the impact of natural catastrophes such as landsliding on the basis of historical records and data owing to the substantial difference in the structure and spatial density of these two types of information it is dif cult to compare them directly and few investigators have attempted this we compared landslide information derived from geomorphological mapping and historical data in a pilot area the staffora river basin northern italy to do this we generated two multivariate statistical models where the dependent variable was either the mapped landslide deposits geomorphological model or the historical sites affected by landslide induced damage historical model by quantitatively comparing these two model maps we demonstrate that the geomorphological model performs better in terms of percentage of terrain units correctly predicted as stable or unstable the historical model underestimates landslide hazard mainly where human structures are lacking however it highlights slopes where landslide movements take place with a high frequency at the temporal scale of human life hence the joint use of these two models may facilitate the knowledge of the overall instability conditions of a given region and the identi cation of the landslides that are most frequently reactivated copyright 2003 john wiley sons ltd

hydrogeological properties of a complex dinaric karst catchment miljacka spring case study miljacka is a karst spring situated in dalmatia croatia the interpretation of the miljacka spring catchment area boundary has repeatedly changed in the past and the main conclusions of previous studies were that the spring which is located in the krka river canyon receives all of its water from another karst river zrmanja here we review a new hypothesis that the miljacka spring receives some of its water from the krka river it was not possible to verify the hypothesis by solely studying the geological composition structural tectonic relations and tracer test results therefore a hydrochemical study was performed to confirm the hypothesis by studying the geological composition it was found that part of the catchment area of the krka river is built of evaporites gypsum and anhydrite which are different in their mineral composition than carbonates the usual rock mass of the dinaric karst the hydrochemical model was made using the netpath win and phreeqc software packages the mixing model results confirmed the hypothesis that the miljacka spring waters come from both the zrmanja including smaller proportion of precipitation infiltrated directly in the karst aquifer and krka rivers this case study shows the great importance of the application of hydrochemical investigations in karst hydrogeology where research is often difficult due to the complexity of the groundwater system

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

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

karst hydrogeology hydrology of dinaric chain and isles this paper gives a comprehensive explanation of the hydrogeological and hydrological characteristics of different water occurrence which exists in the extremely complex dinaric karst system the area and boundaries of the dinaric karst have never been precisely determined it covers about 60 000 km2 stretching the length of the eastern coast of the adriatic sea from the bay of trieste in the north to the drim river basin in the south and the western morava river valley in the east due to very high infiltration rates overland and surface flows are rare in comparison with non karst terrains the dinaric karst is an extremely heterogeneous medium which can be explained only by the use of a great number of measurements points and by continuously monitoring and measuring different parameters the hydrogeological and hydrological regime of all water phenomena in the dinaric karst depends mostly upon the interaction between groundwater and surface water the dominant flow of the groundwater contained in the dinaric karst is towards the adriatic sea through rivers and many permanent and intermittent coastal and submarine springs the paper presents many examples of karst water phenomena from the dinaric karst 1 springs jadro ombla and crnojevica springs 2 open streamflows ljubljanica pazincica dobra lika gacka krka zrmanja and cetina rivers 3 lakes and wetlands cerknica vrana plitvice vransko red and blue lakes and 4 coastal and island karst brac island

tsunami induced sediment transport in the abyssal mediterranean sea an unusual stratigraphic unit nicknamed homogenite fills topographic lows in the complex ridge and trough bathymetry at two survey sites on the western mediterranean ridge and the calabrian ridge on near bottom 4 khz seismic reflection profiles this unit us an acoustically transparent near surface flat lying layer whereas in cores it is a homogeneous gray marl as much as 7 m thick grain size decreases upcore within the unit implying that it was deposited in a single event controlled by gravitational settling the stratigraphic position of the homogenite relative to a firmly dated sapropel bed suggests emplacement between 4400 and 3100 yr b p the source of the homogenite is inferred to be the nearby basin walls farther east two other sites with similar rugged topography lack homogenite entirely a triggering mechanism is required which is capable of initiating massive sediment transport simultaneously in many separate basins at the western two survey sites but which is not effective at the eastern sites a large archeologically recorded earthquake of the correct age is considered and rejected because its epicenter is closer to the nonhomogenite bearing sites than to the sites where this sediment type was observed and because several other earthquakes of comparable magnitude have since been recorded in the area whereas the homogenite is unique the 3 500 yr b p collapse of the caldera of the volcano of santorini caused a huge tsunami which is recorded archeologically and geologically around the eastern mediterranean because of refraction of the tsunami by the bathymetry and because the caldera collapsed in its southwest corner a disproportionate amount of tsunami energy was directed toward the western area where homogenite is observed in contrast the homogenite free sites were relatively sheltered an order of magnitude calculation shows that the near bottom oscillating currents accompanying the santorini tsunami were at or above the threshold erosion velocity at the homogenite bearing sites in addition the near bottom pressure pulse under the tsunami at the homogenite bearing sites was sufficient to cause liquefaction of sediments neither mechanism was adequate to cause sediment transport or slope failure at the homogenite free sites

landslide susceptibility certainty mapping by a multi method approach a case study in the tertiary basin of puy en velay massif central france the present study discusses the use of integrated variables along with a combination of multi method forecasts for landslide susceptibility mapping the study area is located in the south eastern french massif central a volcanic region containing tertiary sedimentary materials that are prone to landslides the flowage type landslides within the study area are very slow moving phenomena which affect the infrastructures and human settlements the modelling process is based on a training set of landslides 70 of total landslides and a set of controlling factor slope lithology surficial formation the topographic wetness index the topographic position index distance to thalweg and aspect we create a composite variable or integrated variable corresponding to the union of geology and surficial formation in order to avoid the conditional dependence between these two variables and to build a geotechnical variable we use five classical modelling methods index weight of evidence logistic regression decision tree and unique condition unit with the same training set but with different architectures of input data made up of controlling factors all the models are tested with a validation group 30 of total landslides using the area under the receiver operating characteristic curve auc to quantify their predictive performance we finally select a single best model for each method however these five models are all equivalent in quality despite their differences in detail so no single model stands out against another finally we combine the five models into a unique susceptibility map with a calculation of median susceptibility class the final auc value of this combined map is better than that for a single model except for unique condition unit and we can evaluate the certainty of the susceptibility class pixel by pixel in agreement with the sparse literature on this topic we conclude that i integrated variables increase the performance of classical modelling processes and ii the combination of multi method forecasts is a pragmatic solution to the inherent problem of choosing the most suitable method for the available data and geomorphological context

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

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

karst rivers particularity an example from dinaric karst croatia bosnia and herzegovina the very complex system of sinking losing and underground transboundary karst rivers lakes and aquifers in the central part of the deep and bare dinaric karst in croatia and bosnia and herzegovina is analysed the groundwater and surface water are hydraulically connected through numerous karst forms which facilitate the exchange of water between the surface and subsurface a complex underground conduit system is an inherent characteristic karst system analysed groundwater and surface water exchange with both adjacent and distant aquifers through underground routes or inflows from surface streams and artificial reservoirs because of a complex surface and underground karst features which strongly influenced its hydrological and hydrogeological regime the main open stream flow with a longitude of about 106 km undergoes eight name changes in this paper it is noted as the eight name river in fact it represents one river with losing sinking and underground stream sections different surface and underground karst forms play crucial roles in the way the water flowing over the surface and on the underground sections of its catchment the analysed area is full of varied and often spectacular surface landforms including for example the blue and red lakes and the kravice waterfall the analyses made in the paper show the existence of a decreasing trend of mean annual discharges on the eight name river which can cause numerous problems in the regional water resource management of this transboundary river and catchment

delineation of landslide hazard areas on penang island malaysia by using frequency ratio logistic regression and artificial neural network models this paper summarizes findings of landslide hazard analysis on penang island malaysia using frequency ratio logistic regression and artificial neural network models with the aid of gis tools and remote sensing data landslide locations were identified and an inventory map was constructed by trained geomorphologists using photo interpretation from archived aerial photographs supported by field surveys a spot 5 satellite pan sharpened image acquired in january 2005 was used for land cover classification supported by a topographic map the above digitally processed images were subsequently combined in a gis with ancillary data for example topographical slope aspect curvature drainage geological litho types and lineaments soil types and normalized difference vegetation index ndvi data and used to construct a spatial database using gis and image processing three landslide hazard maps were constructed on the basis of landslide inventories and thematic layers using frequency ratio logistic regression and artificial neural network models further each thematic layer s weight was determined by the back propagation training method and landslide hazard indices were calculated using the trained back propagation weights the results of the analysis were verified and compared using the landslide location data and the accuracy observed was 86 41 89 59 and 83 55 for frequency ratio logistic regression and artificial neural network models respectively on the basis of the higher percentages of landslide bodies predicted in very highly hazardous and highly hazardous zones the results obtained by use of the logistic regression model were slightly more accurate than those from the other models used for landslide hazard analysis the results from the neural network model suggest the effect of topographic slope is the highest and most important factor with weightage value 1 0 which is more than twice that of the other factors followed by the ndvi 0 52 and then precipitation 0 42 further the results revealed that distance from lineament has the lowest weightage with a value of 0 this shows that in the study area fault lines and structural features do not contribute much to landslide triggering

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

modelling precipitation streamflow processes in karst basin the case of the jordan river sources israel summary a system approach daily precipitation streamflow model was developed for both the base and the surface flow components of large scale karst basins long term streamflow data were separated to baseflow and surface flow using the recursive digital filter method which provides time series for model calibration the hydrological model for karst environment hymke includes attributes to large scale preferential flow that recharge the groundwater and solve the problem of uncorrelated baseflow and surface flow in a karst environment hymke was applied simultaneously to the three major tributaries of the upper catchment of the jordan river which originate in the karstic region of the hermon mountain northern israel it was verified by comparing the calculated surface flow and baseflow with the daily time series of the baseflow separation procedure and demonstrated good agreement of both the surface r2 0 6 and baseflow r2 0 77 components of each stream

after the deluge mediterranean stagnation and sapropel formation in an east mediterranean marine core the upper sapropel begins soon after the start of a global event a very heavy precipitation which occurred in the equatorial latitudes during the late glacial early holocene this heavy precipitation in africa channelled by the nile river across 35 of latitude produced a low salinity surface layer in the east mediterranean in this confined basin with high bottom salinity the steep salinity gradient stratified the water column the stagnant bottom waters triggered the sapropel formation cretaceous sapropels in the tropical oceans may result from the same chain of events in warm humid climates with contrasting wet and dry seasonal rhythm

numerical methods in rock mechanics the purpose of this civilzone review paper is to present the techniques advances problems and likely future development directions in numerical modelling for rock mechanics and rock engineering

caldera development during the minoan eruption thira cyclades greece the well known caldera of thira santorini greece was not formed during a single eruption but is composed of two overlapping calderas superimposed upon a complex volcanic field that developed along a ne trending line of vents before the minoan eruption of 1400 b c thira consisted of three lava shields in the northern half of the island and a flooded depression surrounded by tuff deposits in the southern half andesitic lavas formed the overlapping shields of the north and were contemporaneous with and in many places interbedded with the southern tuff deposits although there appears to be little difference between the composition of magmas erupted differences in eruption style indicate that most of the activity in the northern half of the volcanic field was subaerial producing lava flows whereas in the south eruptions within a flooded depression produced a sequence of mostly phreatomagmatic tuffs many of these tuffs are plastered onto the walls of what appears to have been an older caldera most probably associated with an eruption of rhyodiacitic tephra 100 000 years ago the minoan eruption of about 1400 b c had four distinct phases each reflecting a different vent geometry and eruption mechanism the minoan activity was preceded by minormore eruptions of fine ash 1 the eruption began with a plinian phase from subaerial vent s located on the easternmost of the lave shields 2 vent s grew toward the sw into the flooded depression subsequent activity deposited large scale base surge deposits during vent widening by phreatomagnetic activity 3 the third eruptive phase was also phreatomagmatic and produced 60 of the volume of the minoan tuff this activity was nearly continuous and formed a large featureless tuff ring with poorly defined bedding less

gypsum precipitation from cold brines in an anoxic basin in the eastern mediterranean in 1968 hot brines from which gypsum had precipitated were discovered in the red sea in a divergent plate boundary setting with hydrothermal activity1 we now report the discovery of cold brines in an entirely different geodynamic situation a convergent plate boundary in the eastern mediterranean where the heatflow is very low2 and no hydrothermal activity occurs decimetric pure gypsum crystals precipitate from the cold brines which occupy the bottom of a rimmed anoxic basin near the southern edge of the mediterranean ridge close to the sirte abyssal plain nucleation of the crystals does not occur at the surface but from the deep brines because the salinity of the water is normal down to the depth of 3 000 m we propose the name bacino bannock for this basin after the consiglio nazionale delle ricerche r v bannock from which the bottom water brines were surveyed and sampled

karst spring catchment an example from dinaric karst definition of karst spring catchment or basin area and boundaries belongs to one of the greatest prob lems of karst hydrology and hydrogeology not adequately solved until now this paper tries to address main problems in defining this crucial parameter the theoretical aspect of this issue is discussed in the first two chapters we have presented the example of the catchment area and bound aries definition for the karst spring zrnovnica catchment in dinaric karst topographic catchment area of the zrnov nica spring is 8 4 km 2 the significant discrepancy in size of the hydrological hydrogeological and topographical catchment is very common characteristic for the springs located in the karst areas in the case of the zrnovnica spring the hydrogeological catchment is at least seven times larger than topographic two following simple hydrological methods are used in order to calculate its hydrologic hydrogeologic catchment 1 the relationship between mean annual discharges and annual rainfall falling on the catchment and 2 the turc method it is estimated that hydrogeologic catchment area of the zrnovnica karst spring is much larger and very probably ranges between 60 and 80 km 2 these values represent first rough assessment which should be confirmed by more detailed interdisci plinary investigations according to the performed tracing tests it seems that the catchment spreads on the north east from the topographic catchment and that the zrnovnica spring karst aquifer is fed by groundwater overflow from the neighbouring more abundant karts spring jadro

anoxic events in the mediterranean sea in relation to the evolution of late neogene climates stable isotopic and micropaleontological studies were made of selected sapropels organic rich sediments deposited in the mediterranean sea during the last 5 0 m y to determine the processes responsible for their formation distinct isotopic and faunal changes occur across sapropels of late pleistocene early pleistocene and latest pliocene age while smaller isotopic changes and more stable faunal assemblages are associated with the early and mid late pliocene sapropels the large 18o depletions and euryhaline fauna associated with latest pliocene pleistocene sapropels supports a density stratification model with a low salinity surface layer in contrast early pliocene and mid late pliocene sapropels appear to have been formed as the result of sluggish circulation and low oxygen contents in bottom waters of the eastern mediterranean due to the stable warm climatic conditions of that time period

a new approach in assessing recharge of highly karstified terrains montenegro case studies the recharge of a karst aquifer in terms of its quantity and spatial distribution depends on various natural factors such as climate topography vegetation soil and geology selection of an adequate method for assessing recharge in karst is often a matter of dispute multi parameter methods using geographical information systems tools have recently been successfully developed and applied in karstic terrains of spain and lebanon specific local conditions such as highly karstified terrains could additionally complicate such an assessment the montenegro karstified terrains in the southern part of the external dinarides are characterized by a very high precipitation rate irregular seasonal distribution and absence of surface waters extremely high infiltration capacity of karst considering such conditions an attempt to apply existing knowledge and experiences to the development of an appropriate multi parameter method for assessing spatial distribution of autogenous recharge has been made the karstlop method has been developed applied and calibrated at catchments of several large karst springs of montenegro obtained results in tested catchment areas confirm that with some further improvements the karstlop method could be a useful tool to support research of karstic aquifers in similar highly karstified terrains

african monsoons an immediate climate response to orbital insolation the croll milankovitch astronomical theory of climate1 3 has received strong support from the evidence of a linear climatic forcing by obliquity and precession although nonlinearity had to be assumed for eccentricity4 5 moreover interglacials have appeared to be controlled by the orbital insolation6 although a phase shift of 6 000 5 000 yr is seen between an astronomical climate index and terrestrial climate indicators dominated by the northern ice sheet dynamics climate proxy data of low latitudes are less directly dependent on the ice sheets here it is shown that during the past 464 000 yr african monsoons signalled by the east mediterranean sapropels were heaviest always and only when a northern summer monsoon index computed from the orbital variation of insolation reached maximum values this occurred during all the interglacials but also twice during glacial periods thus tropical aridity is not the single climatic pattern of glacial periods an immediate terrestrial climate response to orbital variations of insolation is established

anoxic basins of the eastern mediterranean an overview it is well known that the mediterranean sea underwent several episodes of basin wide stagnation in the plio pleistocene but extant anoxic basins were first discovered between 1983 and 1984 in the strabo trench and in the southwestern slopes of the mediterranean ridge facing the sirte abyssal plain since then several expeditions were carried out to investigate the geology and physiography of the basins as well as the physical and chemical characters of the water column although the geodynamic settings of the tyro and bannock basins are quite different they are very deep closed and filled by dense salty cold brines whose presence is attributed to submarine dissolution of messinian evaporites bannock basin is interpreted as a collapse basin with a complex configuration central domes and several satellite basins most of which are anoxic unlike the tyro basin it is characterized by precipitation of gypsum occurring as euhedral crystals within the sediments and dredged along the steep wall bordering the main basin to the east the interface separating normal seawater from the brines corresponds to a well defined pycnocline with a density contrast of approximately 20 where strong bacterial activity seems to occur and a sudden decrease in transmittance is recorded studies on the water column document drastic changes of all the various parameters measured o2 h2s ca po4 ba across the interface sediments deposited beneath the brines are anoxic this kind of geologically induced anoxia is persistent and diachronous in contrast with the isochronous episodic repetitive and climatically induced anoxia recorded in the same area of the eastern mediterranean

regional risk assessment of debris flows in china an hru based approach abstract by considering the integrity of microcosmic and comprehensive geomorphological features this article intends to develop a quantitative method for regional risk assessment of debris flow by analyzing the in depth relations among hazard forming environments disaster factors and elements at risk taking the debris flows in the longxi river basin in china as a case study an approach based on the hydrological response unit hru is proposed by establishing both a model and system for regional risk assessment to analyze the hazard of debris flows and the exposure and vulnerability of elements at risk the hru based approach consists of 11 disaster factors topographic slope relative elevation difference lithology channel gradient fault disturbed area rainfall and the type location fragility and economic value of the elements at risk specifically a hazard integrated model is built by considering the hazard factors and their corresponding weights to evaluate the hazard level of debris flow through determining the type quantity distribution economic value and fragility of hazard affected objects in a region methods are established to determine the exposure and vulnerability of different elements at risk validated by using a field study of actual debris flows a debris flow risk map is obtained and the assessment results are in accordance with the actual disaster situation the analyses show that the distributions of zones with high risk and above i e where hazard densities and economic activities are considerably high are closely correlated with the topographic and socioeconomic characteristics of the debris flow catchment these findings suggest that the assessment results provide scientific support for planning measures to prevent or reduce debris flow hazards thus the presented method may serve as a pertinent guidance for regional risk assessment of debris flows in both the longxi river basin and beyond

an expert knowledge based approach to landslide susceptibility mapping using gis and fuzzy logic this paper presents an expert knowledge based approach to landslide susceptibility mapping in an effort to overcome the deficiencies of data driven approaches the proposed approach consists of three generic steps 1 extraction of knowledge on the relationship between landslide susceptibility and predisposing factors from domain experts 2 characterization of predisposing factors using gis techniques and 3 prediction of landslide susceptibility under fuzzy logic the approach was tested in two study areas in china the kaixian study area about 250 km 2 and the three gorges study area about 4600 km 2 the kaixian study area was used to develop the approach and to evaluate its validity the three gorges study area was used to test both the portability and the applicability of the developed approach for mapping landslide susceptibility over large study areas performance was evaluated by examining if the mean of the computed susceptibility values at landslide sites was statistically different from that of the entire study area a z score test was used to examine the statistical significance of the difference the computed z for the kaixian area was 3 70 and the corresponding p value was less than 0 001 this suggests that the computed landslide susceptibility values are good indicators of landslide occurrences in the three gorges study area the computed z was 10 75 and the corresponding p value was less than 0 001 in addition we divided the susceptibility value into four levels low 0 0 0 25 moderate 0 25 0 5 high 0 5 0 75 and very high 0 75 1 0 no landslides were found for areas of low susceptibility landslide density was about three times higher in areas of very high susceptibility than that in the moderate susceptibility areas and more than twice as high as that in the high susceptibility areas the results from the three gorge study area suggest that the extracted expert knowledge can be extrapolated to another study area and the developed approach can be used in large scale projects results from these case studies suggest that the expert knowledge based approach is effective in mapping landslide susceptibility and that its performance is maintained when it is moved to a new area from the model development area without changes to the knowledge base c 2014 elsevier b v all rights reserved

leaky rivers implications of the loss of longitudinal fluvial disconnectivity in headwater streams article i nfo naturally induced longitudinal disconnectivity in the form of channel spanning logjams creates backwaters along headwater streams that reduce velocity and transport capacity create at least temporary storage sites for finer sediment and organic matter and enhance biological processing and uptake of nutrients land uses that reduce wood recruitment and instream storage result in reduced stream complexity and in creased longitudinal connectivity in headwater rivers we examine three scales of naturally occurring longi tudinal disconnectivity in headwater streams of the colorado front range and the implications for channel process and form of historical alterations in disconnectivity basin scale disconnectivity at channel lengths of 10 2 10 3 m results from downstream alternations between steep narrowly confined valley segments with single thread channels and lower gradient wider valley segments with multi thread channels this variation in valley geometry likely reflects differences in average spacing between joints in bedrock outcrops which influences bedrock weathering and erosion greater volumes of wood stored in the wide valley seg ments correlate with more closely spaced channel spanning logjams and greater storage of fine sediments and organic matter reach scale disconnectivity at channel lengths of 10 1 10 2 m results from the presence of numerous closely spaced channel spanning logjams which cumulatively store substantial amounts of fine sediment and organic matter the backwater effects associated with an individual jam can result in the accumulation of up to 11 m 3 of fine sediment upstream from the jam of which as much as 21 is organic

the application of gis based logistic regression for landslide susceptibility mapping in the kakuda yahiko mountains central japan as a first step forward in regional hazard management multivariate statistical analysis in the form of logistic regression was used to produce a landslide susceptibility map in the kakuda yahiko mountains of central japan there are different methods to prepare landslide susceptibility maps the use of logistic regression in this study stemmed not only from the fact that this approach relaxes the strict assumptions required by other multivariate statistical methods but also to demonstrate that it can be combined with bivariate statistical analyses bsa to simplify the interpretation of the model obtained at the end in susceptibility mapping the use of logistic regression is to find the best fitting function to describe the relationship between the presence or absence of landslides dependent variable and a set of independent parameters such as slope angle and lithology here an inventory map of 87 landslides was used to produce a dependent variable which takes a value of 0 for the absence and 1 for the presence of slope failures lithology bed rock slope relationship lineaments slope gradient aspect elevation and road network were taken as independent parameters the effect of each parameter on landslide occurrence was assessed from the corresponding coefficient that appears in the logistic regression function the interpretations of the coefficients showed that road network plays a major role in determining landslide occurrence and distribution among the geomorphological parameters aspect and slope gradient have a more significant contribution than elevation although field observations showed that the latter is a good estimator of the approximate location of slope cuts using a predicted map of probability the study area was classified into five categories of landslide susceptibility extremely low very low low medium and high the medium and high susceptibility zones make up 8 87 of the total study area and involve mid altitude slopes in the eastern part of kakuda mountain and the central and southern parts of yahiko mountain

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

karst geomorphology of carbonatic conglomerates in the folded molasse zone of the northern alps austria germany abstract the folded molasse zone of the northern alps consists of clastic sedimentary rocks that are usually not considered to be karstifiable however large areas within this zone are composed of carbonatic conglomerates numerous karst landforms have recently been discovered but are not recorded on official maps and in the literature therefore a research programme was initiated at the hochgrat site austria germany that included geomorphological mapping and characterisation of the karst phenomena both fracture controlled and hydrodynamically controlled karren were observed on conglomerate outcrops the predominant karst landforms dolines are typically circular funnel shaped most often 2 to 9 m in diameter 1 to 6 m deep and frequently act as swallow holes poljes that are atypically small 1 ha occur in either glacial cirques or syncline depressions are flat floored and lined with sediment and soil and drain underground via swallow holes short caves springs with marked discharge variations and estavelles are further evidence for karst development karstic landforms are widespread in carbonatic conglomerate terrains but their dimensions are smaller than in typical limestone karst the practical implications of these findings are also briefly mentioned in this paper

tectonics of the hellenic trench a synthesis of sea beam and submersible observations abstract detailed bathymetric investigations were performed in four zones of the hellenic trench system in 1978 using the multi narrow beam echo sounder sea beam on r v jean charcot in 1979 a field study using the 3000 m submersible cyana was conducted in three of the four sites covered by sea beam we summarize here the principal tectonic results of these studies and publish the corresponding sea beam maps it is shown that compressional structures affect the sedimentary cover of the outer wall and trench whereas extensional tectonics is present on the inner wall in addition there is evidence that most of the upper sedimentary cover is not subducted but rather piles up in front of the trench to form the mediterranean ridge we suggest that the surface limit of the zone of mechanical decoupling occurs near the base of the inner wall we show that the gross structure of the trench as well as the strain pattern observed is controlled by the kinematics of subduction and we discuss its evolution since its initiation about 13 m y ago

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

landslide susceptibility mapping of the slopes in the residual soils of the mengen region turkey by deterministic stability analyses and image processing techniques abstract the aim of the present study is to prepare a landslide susceptibility map of a region of about 120 km2 between gokcesu and pazarkoy around mengen nw turkey at approximately 10 km north of the north anatolian fault zone where frequent landslides occur for this purpose mechanisms of the landslides were studied by two dimensional stability analyses together with field observations and the parameters controlling the development of such slides were identified field observations indicated that the failures generally developed within the unconsolidated and or semiconsolidated soil units in forms of rotational successive shallow landslides within the weathered zone in mengen cukurca and sazlar formations although consisting of residual soils capak and gokdag formations do not exhibit landslides as the natural slopes formed on these do not exceed the critical slope angles statistical evaluations and distribution of the landslides on the topographical map showed that such parameters as cohesion angle of internal friction slope relative height orientation of slopes proximity to drainage pattern vegetation cover and proximity to major faults were the common features on the landslides digital images were obtained to represent all these parameters on gray scale on the spot image and on the digital elevation model dem of the area using image processing techniques soil mechanics tests were carried out on 36 representative samples collected from different units and parameters were determined for two dimensional stability analyses basing on sensitivity approach and for the preparation of digital shear strength map in order to determine the critical slope angle values for the residual soils a series of sensitivity analyses were realized by using two dimensional deterministic slope stability analyses techniques for varying values of cohesion angle of internal friction and slope height along with varying saturation conditions according to the results of the sensitivity analyses the mengen formation was found to be most susceptible unit to landslides covering about 33 5 of the region studied in terms of surface area the distribution of the critical slopes were determined by superimposing the critical slope values from sensitivity analyses on slope map of the study area on the other hand iso cohesion and iso friction maps were produced by locating the values of cohesion and internal friction angles in a geographic coordinate system such that they coincide with sample locations on the dem and by further interpolation of the values concerned the pixel values were evaluated in gray scale from 0 to 255 0 representing the lowest pixel value and 255 representing the highest sensitivity analyses on cohesion and angle of internal friction to investigate the effects of these parameters only on stability revealed that cohesion was effective at a rate of 70 by itself while angle of internal friction alone controlled the stability by a rate of 30 the iso cohesion and iso friction maps previously obtained were digitally combined in these rates and a shear strength map was prepared the geographic setting of the study area is such that northern slopes usually receive dense precipitation in relation to this fact about 42 of the landslides are due north thus a slope orientation map was prepared using the dem and slopes facing north were evaluated as being more susceptible to sliding proximity to the drainage pattern was another important factor in the evaluation as streams could adversely affect the stability by either eroding the toe or saturating the slope or both when considered together in conjunction with the field observations faults and landslides showed a close association in the area about 88 of the landslides were detected within an area closer than 250 m to major faults therefore a main discontinuity map was produced using the spot image of the region and proximity to major faults was evaluated as a parameter as most of the landslides developed in areas where the vegetation was rather sparse a vegetation cover map was therefore obtained from the spot image and the areas with denser vegetation were considered to be less susceptible to sliding with respect to the areas with less or no vegetation having prepared the maps accounting for the distribution of critical slopes shear strength properties relative height slope angle orientation of the slopes vegetation cover proximity to the drainage pattern geographic corrections were carried on each of these and a potential failure map was obtained for the residual soils by superimposing all these maps next a classification was performed on the final map and five relative zones of susceptibility were defined when compared with this map all of the landslides identified in the field were found to be located in the most susceptible zone the performance of the method used in processing the images appears to be quite high the zones determined on the map being the zones of relative susceptibility

landslide susceptibility mapping using geological data a dem from aster images and an artificial neural network ann an efficient and accurate method of generating landslide susceptibility maps is very important to mitigate the loss of properties and lives caused by this type of geological hazard this study focuses on the development of an accurate and efficient method of data integration processing and generation of a landslide susceptibility map using an ann and data from aster images the method contains two major phases the first phase is the data integration and analysis and the second is the artificial neural network training and mapping the data integration and analysis phase involve gis based statistical analysis relating landslide occurrence to geological and dem digital elevation model derived geomorphological parameters the parameters include slope aspect elevation geology density of geological boundaries and distance to the boundaries this phase determines the geological and geomorphological factors that are significantly correlated with landslide occurrence the second phase further relates the landslide susceptibility index to the important geological and geomorphological parameters identified in the first phase through ann training the trained ann is then used to generate a landslide susceptibility map landslide data from the 2004 niigata earthquake and a dem derived from aster images were used the area provided enough landslide data to check the efficiency and accuracy of the developed method based on the initial results of the experiment the developed method is more than 90 accurate in determining the probability of landslide occurrence in a particular area

gis based landslide susceptibility mapping for the 2005 kashmir earthquake region abstract the m w 7 6 october 8 2005 kashmir earthquake triggered several thousand landslides throughout the himalaya of northern pakistan and india these were concentrated in six different geomorphic geologic anthropogenic settings a spatial database which included 2252 landslides was developed and analyzed using aster satellite imagery and geographical information system gis technology a multi criterion evaluation was applied to determine the significance of event controlling parameters in triggering the landslides the parameters included lithology faults slope gradient slope aspect elevation land cover rivers and roads the results showed four classes of landslide susceptibility furthermore they indicated that lithology had the strongest influence on landsliding particularly when the rock is highly fractured such as in shale slate clastic sediments and limestone and dolomite moreover the proximity of the landslides to faults rivers and roads was also an important factor in helping to initiate failures in addition landslides occurred particularly in moderate elevations on south facing slopes shrub land grassland and also agricultural land were highly susceptible to failures while forested slopes had few landslides one third of the study area was highly or very highly susceptible to future landsliding and requires immediate mitigation action the rest of the region had a low or moderate susceptibility to landsliding and remains relatively stable this study supports the view that 1 earthquake triggered landslides are concentrated in specific zones associated with event controlling parameters and 2 in the western himalaya deforestation and road construction contributed significantly to landsliding during and shortly after earthquakes

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

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

the effect of river dynamics induced by the messinian salinity crisis on karst landscape and caves example of the lower ardeche river mid rhone valley abstract the karstic canyon of lower ardeche is located in the middle rhone valley which is directly tributary to the mediterranean sea the rhone river is emblematic of the messinian salinity crisis msc impact on landscape morphology along the edge of the saint remeze plateau the rhone valley displays four benchmark levels generated by the msc the pre evaporitic abandonment surface 1 the messinian erosional surface 2 the marine non marine surface of the pliocene ria 3 and the pliocene abandonment surface 4 the study of these benchmark levels allows us to reconstruct the evolution of the regional base level over the last 6 ma we obtain a curve for base level evolution that provides a geodynamic reference which is used to investigate the morphogenesis of the saint remeze karstic plateau the ardeche river downcuts the saint remeze plateau in a deep canyon from vallon pont d arc to the west to its confluence with the rhone to the east several abandoned valleys are present along the western edge of the saint remeze plateau at the inlet of the ardeche canyon in these abandoned valleys the fluvial deposits are related to several periods from the pliocene onwards they provide important insights into the fluvial dynamics a 160 m thick aggradation sequence infilled the ardeche canyon during the pliocene this aggrading river caused the first lateral shifting as an aggradation epigenesis this first infilling shows that the ardeche canyon already existed before the pliocene secondly it has been demonstrated that the ardeche canyon is downcut into the pre evaporitic surface of the saint remeze plateau dated to 5 45 ma martini j 2005 etude des paleokarsts des environs de saint remeze ardeche france mise en evidence d une riviere souterraine fossilisee durant la crise de salinite messinienne karstologia 45 46 1 18 consequently the canyon downcutting is entirely due to the msc and occurred during a time span of only 100 000 years based on these observations it is possible to elucidate the curve of the regional base level evolution hence we are able to propose a new interpretation of the geomorphological evolution of the saint remeze karstic plateau and its cave levels for the last 6 ma the cave levels consist in underground short cuts of the surface meanders they mainly developed during the pliocene aggradation cycle the chauvet cave famous for its palaeolithic paintings corresponds to one of these underground short cuts the aggradation period ends at the end of the pliocene with long high level riverbed stability it favours the development of large low gradient surfaces as pediments the complete messinian pliocene eustatic cycle is responsible for the downcutting of the ardeche canyon and its infilling during the pliocene consequently karst developed according to the base level oscillations as low gradient surfaces and as cave levels for the study of the peri mediterranean caves and karst areas we propose to apply the lower ardeche valley evolution model based on the base level oscillations during and after the msc

landslide susceptibility analysis in central vietnam based on an incomplete landslide inventory comparison of a new method to calculate weighting factors by means of bivariate statistics abstract vietnam is regarded as a country strongly impacted by climate change population and economic growth result in additional pressures on the ecosystems in the region in particular changes in landuse and precipitation extremes lead to a higher landslide susceptibility in the study area approx 12 400 km 2 located in central vietnam and impacted by a tropical monsoon climate hence this natural hazard is a serious problem in the study area a probability assessment of landslides is therefore undertaken through the use of bivariate statistics however the landslide inventory based only on field campaigns does not cover the whole area to avoid a systematic bias due to the limited mapping area the investigated regions are depicted as the viewshed in the calculations on this basis the distribution of the landslides is evaluated in relation to the maps of 13 parameters showing the strongest correlation to distance to roads and precipitation increase an additional weighting of the input parameters leads to better results since some parameters contribute more to landslides than others the method developed in this work is based on the validation of different parameter sets used within the statistical index method it is called omit error because always omitting another parameter leads to the weightings which describe how strong every single parameter improves or reduces the objective function furthermore this approach is used to find a better input parameter set by excluding some parameters after this optimization nine input parameters are left and they are weighted by the omit error method providing the best susceptibility map with a success rate of 92 9 and a prediction rate of 92 3 this is an improvement of 4 4 and 4 2 respectively compared to the basic statistical index method with the 13 input parameters

mediterranean quaternary sapropels an immediate response of the african monsoon to variation of insolation abstract in the subsurface of the east mediterranean sea eleven discrete basin wide organic rich black sapropels were deposited during the last 465 000 years they are dated by oxygen isotopic chronostratigraphy the most recent sapropel has been shown to be the consequence of heavy nile river summer floods due to increased monsoonal summer precipitation over ethiopia and not of scandinavian ice sheet meltwater influx into the east mediterranean sea as was previously believed while most sapropels were deposited during interglacials two thick sapropels formed during glacial periods as shown by their position in the oxygen isotopic stratigraphy and by their pollen record in core rc9 181 the new evidence presented here is that the sapropel sequence in this core including the two glacial sapropels correlates on a one to one basis with the highest values of an index of insolation on top of the atmosphere the concept of this index derives from an analysis of the african monsoon process the index variation is computed for the last 465 000 years from the caloric northern summer insolation in the tropical latitudes controlled by variations of the earth s orbital parameters it is conjectured that this index might be linked through the climate system to the monsoonal precipitation which in africa produces the nile river summer flood

recent sapropel formation in the eastern mediterranean during the 1983 expedition of the rv tyro in the eastern mediterranean a combined programme of seismological micropalaeontological and geochemical research was performed the geochemical research focused mainly on the interstitial water and the chemical composition and origin of sapropels for this purpose box cores piston cores and bottom water samples were collected we report here that some of these cores showed clear evidence of long term stagnant bottom water conditions in a small basin south of crete for which we propose the name tyro basin 1 the bottom water is strongly anoxic whereas the sediment down to at least 400 cm is sapropel to sapropelic as salt concentrations in the bottom water are eight times higher than in normal seawater the anoxic conditions in this basin are probably due indirectly to dissolution of salt from a nearby diapir

human and natural impacts on fluvial and karst depressions of the maya lowlands abstract this paper begins to differentiate the major drivers and chronology of erosion and aggradation in the fluvial and fluviokarst landscapes of the southern and central maya lowlands we synthesize past research on erosion and aggradation and add new data from water soils radiocarbon dating and archaeology to study the quantity timing and causes of aggradation in regional landscape depressions geomorphic findings come from many excavations across a landscape gradient from upland valleys karst sinks and fans into the coastal plain floodplains and depressions findings from water chemistry show that sources in the uplands have low quantities of dissolved ions but water in the coastal plains has high amounts of dissolved ions often nearly saturated in calcium and sulfate we found significant geomorphic complexity in the general trends in upland karst sinks in a few instances sediments preserve late pleistocene paleosols buried 2 3 m though many more have distinct middle to late holocene paleosols buried 1 2 m after c 2300 bp maya early to late preclassic from 2300 1100 bp late preclassic to classic periods the landscape aggraded from five main mechanisms river flooding climatic instability accelerated erosion ancient maya landscape manipulation and gypsum precipitation from a rise in a water table nearly saturated in calcium and sulfate ions evidence exists for two or three high magnitude floods possibly driven by hurricanes moreover lake core and geophysical studies from the peten lakes region have shown high rates of deposition of silicate clays maya clays starting and peaking during the maya preclassic and continuing to be high through the late classic the main driver on upland karst depressions the peten lakes upland valleys and fans was accelerated soil erosion but water table rise probably driven by sea level rise was the main driver on the wetlands of the coastal plain because the aggraded sediments here are dominantly composed of gypsum precipitated from the groundwater this latter mechanism represents a little recognized mechanism of aggradation over a large region these large scale environmental changes occurred during periods of intensive ancient maya land use and climatic instability both of which may have contributed to erosion by increasing runoff despite these geomorphic changes ancient maya farmers adapted in several key cases