shallow marine carbon and oxygen isotope and elemental records indicate icehouse greenhouse cycles during the early jurassic 1 for much of the mesozoic record there has been an inconclusive debate on the possible global significance of isotopic proxies for environmental change and of sequence stratigraphic depositional sequences we present a carbon and oxygen isotope and elemental record for part of the early jurassic based on marine benthic and nektobenthic molluscs and brachiopods from the shallow marine succession of the cleveland basin uk the invertebrate isotope record is supplemented with carbon isotope data from fossil wood which samples atmospheric carbon new data elucidate two major global carbon isotope events a negative excursion of 2 at the sinemurian pliensbachian boundary and a positive excursion of 2 in the late pliensbachian the sinemurian pliensbachian boundary event is similar to the slightly younger toarcian oceanic anoxic event and is characterized by deposition of relatively deepwater organic rich shale the late pliensbachian strata by contrast are characterized by shallow marine deposition oxygen isotope data imply cooling locally for both events however because deeper water conditions characterize the sinemurian pliensbachian boundary in the cleveland basin the temperature drop is likely of local significance in contrast a cool late pliensbachian shallow seafloor agrees with previous inference of partial icehouse conditions both the large scale long term and small scale short duration isotopic cycles occurred in concert with relative sea level changes documented previously from sequence stratigraphy isotope events and the sea level cycles are concluded to reflect processes of global significance supporting the idea of an early jurassic in which cyclic swings from icehouse to greenhouse and super greenhouse conditions occurred at timescales from 1 to 10 ma

a scenario study of seismically induced landsliding in seattle using broadband synthetic seismograms abstract we demonstrate the value of utilizing broadband synthetic seismograms to assess regional seismically induced landslide hazard focusing on a case study of an m w 7 0 seattle fault earthquake in seattle washington we computed broadband synthetic seismograms that account for rupture directivity and 3d basin amplification we then adjusted the computed motions on a fine grid for 1d amplifications based on the site response of typical geologic profiles in seattle and used these time series ground motions to trigger shallow landsliding using the newmark method the inclusion of these effects was critical in determining the extent of landsliding triggered we found that for inertially triggered slope failures modeled by the newmark method the ground motions used to simulate landsliding must have broadband frequency content in order to capture the full slope displacement we applied commonly used simpler methods based on ground motion prediction equations for the same scenario and found that they predicted far fewer landslides if only the mean values were used but far more at the maximum range of the uncertainties highlighting the danger of using just the mean values for such methods our results indicate that landsliding triggered by a large seattle fault earthquake will be extensive and potentially devastating causing direct losses and impeding recovery the high impact of landsliding predicted by this simulation shows that this secondary effect of earthquakes should be studied with as much vigor as other earthquake effects online material high resolution maps of relative seismically induced landslide hazard for an m w 7 0 seattle fault earthquake for dry and saturated soil conditions

from rifting to drifting africa is splitting apart down the east african rift an analysis of the relative motion of the tectonic plates involved allows the rate of continental rifting to be estimated

carbon isotope records of the early jurassic toarcian oceanic anoxic event from the valdorbia umbria marche apennines and monte mangart julian alps sections palaeoceanographic and stratigraphic implications the toarcian oceanic anoxic event ca 183 ma coincides with a global perturbation marked by enhanced organic carbon burial and a general decrease in calcium carbonate production probably triggered by changes in the composition of marine plankton and elevated carbon dioxide levels in the atmosphere this study is based on high resolution sampling of two stratigraphic successions located in valdorbia umbria marche apennines and monte mangart julian alps italy which represent expressions of the toarcian oceanic anoxic event in deep water pelagic sediments these successions are characterized by the occurrence of black shales showing relatively low total organic carbon concentrations compared with coeval strata in northern europe generally 2 and low hydrogen indices on this basis they are similar to other toarcian black shales described from the tethyan region the positive and negative carbon isotope records from the two localities permit a high resolution correlation such that ammonite biostratigraphy information from valdorbia can be transferred to those parts of the monte mangart section that lack these fossils spectral analyses ofd 13 corg values and of caco3 percentages from the sedimentary records of both the valdorbia and monte mangart sections reveal a strong cyclic pattern best interpreted as an eccentricity signal which hence implies a duration of ca 500 kyr for the negative carbon isotope excursion based on the carbon isotope curves obtained the high resolution correlation between the italian successions and a section in yorkshire northern europe confirms the supposition that the apparent mismatch between the dating of the toarcian oceanic anoxic event in the boreal and tethyan realms is an artefact of biostratigraphy

numerical analysis on influence of principal parameters of topography on hillslope instability in a small catchment this study was conducted to identify the influence of three principal parameters constituting topography slope inclination soil depth and slope length on hillslope instability in a small catchment known as higashifukubegawa of shikoku island western japan the typhoon rainfall of 19 20 october 2004 was significant in causing a total of seven slope failures in the catchment though other rainfall events of various intensities in the same year did not cause failure to understand the influence of the three principal parameters numerical modeling of seepage and slope stability was performed in slope profiles constructed by varying the three parameters across their permissible range prepared from the seven slope failures of higashifukubegawa in geostudio geostudio tutorials includes student edition lessons geo slope international ltd calgary 2005 v 4 the change in porewater pressure and slope mass weight due to variation in values of principal parameters was used to interpret the change in factor of safety or instability the results showed that 1 instability increases with increase in the values of all three selected parameters across their range in higashifukubegawa with remarkable decreasing trend in factors of safety 2 slope inclination and soil depth were observed to affect instability through change in both unsaturated zone moisture content and mobilizing force of slope mass 3 but with slope length the unsaturated zone moisture content was not found to change considerably which implies that the instability due to slope length is mainly governed by change in slope mass weight overall this study has dealt in great detail with how hillslope instability changes with principal parameters of topography under the same simulating conditions of hydrological and geo mechanical parameters

potential for landsliding dependence on hyetograph characteristics 1 this paper examines the effect of hyetograph shape on the potential for landsliding in soil mantled landscapes an existing pore pressure response model iverson 2000 is used to study the effects of unsteady rainfall infiltration in hillslopes and the effect of slope and convergent topography is expressed using a steady state model of slope parallel subsurface flow slope stability is assessed using an infinite slope analysis this theoretical framework is coupled with simple hyetograph models and to intensity duration frequency functions to determine the return period of landslide triggering rainfall results also show that hyetographs with a peak at the end of a rainfall event have a stronger destabilizing effect than hyetographs with a constant rainfall or with a peak at the beginning of a storm thus the variability of hyetograph shapes adds uncertainty to the assessment of landsliding triggered by rainfall

a simplified physically based coupled rainfall threshold model for triggering landslides abstract a number of rainfall threshold models for triggering landslides have been developed in either empirical or physical manner the objective of an empirical rainfall threshold model is to establish a relationship between rainfall intensity and duration which is a line on a log log diagram although the mechanism of the relationship following the power law is not yet well understood the sufficiency of rainfall and landslide data is also a significant concern for empirical models a simplified physically based rainfall threshold model is developed by coupling the mohr coulomb law and darcy s law based on the assumptions that the slope has an infinite length and that discrete water diffusion is physically based the power law mechanism for the relationship between rainfall intensity and duration for the initiation of a landslide is investigated using this physically based model the rainfall threshold calculated with the model shows that the threshold follows the power law for short rainfall durations whereas it gradually tends towards a constant value for long rainfall durations case studies have shown that a plausible threshold for regions that lack sufficient landslide and rainfall data can be obtained via the model the model is also applied to cases which occurred in regions geologically typical of fujian province southeast china the landslide distribution predicted by our model accords with the interpretation of high resolution satellite imagery and this suggests that the proposed physically based model also effectively determines rainfall thresholds for triggering regional landslides

assessment of rainfall induced shallow landslide susceptibility using a gis based probabilistic approach abstract this study proposes a probabilistic analysis method to assess shallow landslide susceptibility over an extensive area by integrating an infinite slope model with gis geographic information system and monte carlo simulation taking into consideration the inherent uncertainty and variability in input parameters the mechanical parameters of soil materials such as cohesion and friction angle used in the infinite slope analysis have been identified as the major source of uncertainty because of their spatial variability therefore these parameters were considered as random variables in this probabilistic landslide analysis to properly account for the uncertainty in input parameters the probabilistic analysis method used was monte carlo simulation the process was carried out in a gis based environment because gis has effective spatial data processing capacity over broad areas in addition the hydrogeological model was coupled with the infinite slope model to evaluate increases in pore water pressure caused by rainfall the proposed approach was applied to a practical example to evaluate its feasibility the landslide inventory map and the spatial database for input parameters were constructed in a grid based gis environment and a probabilistic analysis was implemented using monte carlo simulation to evaluate the performance of the model the results of the probabilistic landslide susceptibility analysis were compared with the landslide inventory the probabilistic approach demonstrated good predictive performance when compared with the landslide occurrence location in addition deterministic analysis was carried out using fixed single input data for comparison with the results from the proposed approach in this comparison the probabilistic analysis showed better performance than the deterministic analysis in addition the results showed that proper consideration and understanding of uncertainties play an important role in accurately predicting shallow landslide susceptibility

influence of hydraulic properties on physically modelling slope stability and the definition of rainfall thresholds for shallow landslides abstract physically based models are recognized as a good tool for slope stability analysis and have been implemented for the definition of rainfall thresholds for landslides in this study a methodology for estimating rainfall intensity and duration thresholds for shallow sliding failure using the physical model trigrs was implemented in a tropical mountainous basin of the valle de aburra colombia the variation of pressure head and factor of safety during different rainfall events and hydraulic conditions is studied for specific grid cells steady state and a maximum pressure head were reached for each grid cell regardless of the different rainfall intensities and hydraulic conductivities simulated but the time in which this condition is reached depends on these variables and occurs faster for steeper slopes the influence of hydraulic properties on the stability results and the position of the rainfall intensity and duration thresholds were studied with parametric analysis very low values of saturated hydraulic conductivity do not allow rainfall intensity and duration thresholds to be developed the rainfall threshold position also has a greater variation with respect to the parameters of the soil water retention curve and the initial infiltration rate or long term background rainfall rate for low values of saturated hydraulic conductivity

raising the colorado plateau shallow marine rocks exposed on the 2 km high 45 km thick colorado plateau in the western united states indicate that it was near sea level during much of the phanerozoic isostatic calculations however illuminate the difficulty in maintaining a 45 km thick crust at or near sea level we propose that an isostatically balanced 30 km thick proto colorado plateau crust was thickened during the late cretaceous to early tertiary by intracrustal flow out of an overthickened sevier orogenic hinterland this plateau would have been supported by a thick 70 km crustal root which is proposed to have been the source region for hot and weak mid crustal material that flowed eastward from the plateau toward the low elevation proto colorado plateau

carbon isotope anomalies and demise of carbonate platforms in the sinemurian early jurassic of the tethyan region evidence from the southern alps northern italy despite its global impact on ecosystems the triassic jurassic boundary event had only a modest effect on the carbonate depositional systems of the southern alps whereas a fundamental reorganization of the same palaeogeographic area took place during the sinemurian age this paper investigates whether or not the well documented demise of sinemurian carbonate platforms in the tethyan region was a response to a global event by examination of carbon isotope anomalies in successions of different facies that record this interval of time a chemostratigraphic transect from lake garda up to the eastern italian border is illustrated by four stratigraphic sections high resolution 20 cm over key intervals chemostratigraphic sampling allowed detection of a major negative 13 c anomaly of 1 5 preceded by a positive excursion both in shallow and deep water successions over the stratigraphical range of the ammonite genus arnioceras a comparison with sections from the uk suggests that the positive excursion belongs to the turneri zone and the succeeding negative excursion falls within the obtusum zone in the deep water belluno basin the negative anomaly occurs in a biogenic chert rich unit recording the onset of mesotrophic conditions in the basin in the platform carbonate successions this major negative carbon isotope excursion is developed within a calcarenitic unit corresponding to the lowest occurrence of the foraminifer paleomayncina termieri this evidence for deepening and transgression across the carbonate platform suggests pre conditioning for drowning hence rather than tectonic subsidence alone environmental factors may have aided the demise of tethyan carbonate platforms during the early jurassic sinemurian age

biosedimentology of the early jurassic post extinction carbonate depositional system central high atlas rift basin morocco this study documents a liassic example of the long ranging effects of mass extinction on carbonate systems biohistoric constraints inherent in the liassic carbonate depositional system are deciphered from normal marine sub tidal deposits of the central high atlas rift basin morocco through hettangian sinemurian to early toarcian times the integration of results from the analysis of lithofacies depositional geometries microfacies macrobenthos carbonate build ups carbon and oxygen stable isotopes and rare earth element yttrium distribution patterns allows the intrinsic or biohistoric control on the central high atlas deposits to be separated from extrinsic factors such as basin development and palaeoclimate the survival interval in the aftermath of the end triassic mass extinction persisted until the early sinemurian indicated by a severely depleted carbonate system impoverished in skeletal organisms a tectonic pulse at the early to late sinemurian boundary interval caused a basin widening with immigration of a marine fauna however until the latest sinemurian macdonelli subzone of the raricostatum zone the deposits were dominated by filter feeding benthic heterotrophs sponges brachiopods polychaetes and crinoids during this stage primary production within the enlarged basin must have been largely planktonic and there was a net flux of organic matter to the sea floor oxygen minimum zone a regional radiation of organic walled phytoplankton is inferred to explain the selective success of the filter feeding community and the occurrence of sponge mounds thus significant effects of the end triassic mass extinction are still present during the late sinemurian through almost the entire pliensbachian a highly productive shoal rimmed carbonate platform existed it developed subsequent to tectonic reorganization and a marine recirculation event radiolarian facies 13c 1 1 strongly negative ce anomaly photosymbiotic sediment producers mainly large bivalves now state the success of specialists and environmental equilibrium conditions in the latest pliensbachian the climax stage was reached with the development of a coralgal reef rimmed carbonate platform the liassic carbonate depositional system experienced a terminal multicausal early toarcian drowning event during which most of the large bivalves became extinct

transient deterministic shallow landslide modeling requirements for susceptibility and hazard assessments in a gis framework abstract application of transient deterministic shallow landslide models over broad regions for hazard and susceptibility assessments requires information on rainfall topography and the distribution and properties of hillside materials we survey techniques for generating the spatial and temporal input data for such models and present an example using a transient deterministic model that combines an analytic solution to assess the pore pressure response to rainfall infiltration with an infinite slope stability calculation pore pressures and factors of safety are computed on a cell by cell basis and can be displayed or manipulated in a grid based gis input data are high resolution 1 8 m topographic information derived from lidar data and simple descriptions of initial pore pressure distribution and boundary conditions for a study area north of seattle washington rainfall information is taken from a previously defined empirical rainfall intensity duration threshold and material strength and hydraulic properties were measured both in the field and laboratory results are tested by comparison with a shallow landslide inventory comparison of results with those from static infinite slope stability analyses assuming fixed water table heights shows that the spatial prediction of shallow landslide susceptibility is improved using the transient analyses moreover results can be depicted in terms of the rainfall intensity and duration known to trigger shallow landslides in the study area

sequence development in an isolated carbonate platform lower jurassic djebel bou dahar high atlas morocco influence of tectonics eustacy and carbonate production six sequences each with a distinct shape stratal anatomy bounding surfaces lithofacies composition and stacking patterns were identified in the djebel bou dahar isolated carbonate platform which developed in a half graben in the high atlas marine rift basin during the early jurassic sequences are believed to have a complex multi process origin as the result of tectonic processes regional subsidence and fault block rotation overprinting the eustatic signal in addition changing carbonate producers with shifting centres of deposition and relative accumulation potential influenced the filling and anatomy of the accommodation space that had been created by the hybrid tectonic and eustatic processes sequences i and ii are tabular in shape and interpreted to primarily reflect the combined processes of uniform tectonic subsidence and eustacy which resulted in a ramp to shelf carbonate system with lagoon and tidal flat lithofacies onset of a rifting episode around the base of the lotharingian and fault block rotation were responsible for the development of the angular unconformity with the underlying sequence ii and the progressive development of a shallow water isolated platform and the wedge shaped depositional sequences iii to vi during the lotharingian and pliensbachian concurrent variations in palaeoceanographic conditions and in the carbonate factory caused a shift towards a flat topped platform geometry with high energy coated grains and sub photic sponge microbial deposition around the margin the aggradational to retrogradational character of sequences iii iv and vi is inferred to be a result of the combined effect of in situ carbonate production coupled with high rates of creation of accommodation space in the hanging wall environmental effects on carbonate production were the most probable cause for drowning of the djebel bou dahar platform during the toarcian but also influenced the filling and geometry of sequences iv to vi this study suggests that the commonly accepted model of pulse driven sequence development in half grabens may not be fully applicable for the djebel bou dahar where a more continuous rotation at sequence scale associated with subsidence pulses of the djebel bou dahar block seems to have interacted with eustacy and carbonate production to generate sequences continuous rotation is suggested by the presence of regular patterns of diverging strata and numerous minor exposure surfaces in lagoonal deposits of sequences v and vi in addition this study demonstrates that eustacy and variations in the carbonate factory might be as significant as tectonics in sequence development and platform drowning in carbonate platforms within rift basins this observation could imply that the effects of eustacy and the carbonate factory might not have been correctly recognized in other similar carbonate platforms due to a tectonic biased interpretation

raising the colorado plateau comment and reply comment mcquarrie and chase 2000 1 proposed three tests for their novel model first that it is possible to account for the elevation of the colorado plateau in their model by reasonable variation of crustal thickness second that mechanical parameters required of their model assume reasonable values

modeling landslide recurrence in seattle washington usa abstract to manage the hazard associated with shallow landslides decision makers need an understanding of where and when landslides may occur a variety of approaches have been used to estimate the hazard from shallow rainfall triggered landslides such as empirical rainfall threshold methods or probabilistic methods based on historical records the wide availability of geographic information systems gis and digital topographic data has led to the development of analytic methods for landslide hazard estimation that couple steady state hydrological models with slope stability calculations because these methods typically neglect the transient effects of infiltration on slope stability results cannot be linked with historical or forecasted rainfall sequences estimates of the frequency of conditions likely to cause landslides are critical for quantitative risk and hazard assessments we present results to demonstrate how a transient infiltration model coupled with an infinite slope stability calculation may be used to assess shallow landslide frequency in the city of seattle washington usa a module called crf critical rainfall for estimating deterministic rainfall thresholds has been integrated in the trigrs transient rainfall infiltration and grid based slope stability model that combines a transient one dimensional analytic solution for pore pressure response to rainfall infiltration with an infinite slope stability calculation input data for the extended model include topographic slope colluvial thickness initial water table depth material properties and rainfall durations this approach is combined with a statistical treatment of rainfall using a gev general extreme value probabilistic distribution to produce maps showing the shallow landslide recurrence induced on a spatially distributed basis as a function of rainfall duration and hillslope characteristics

kinematic implications of joint zones and isolated joints in the navajo sandstone at zion national park utah evidence for cordilleran relaxation 1 at zion national park znp the landscape is a consequence of differential weathering of the navajo sandstone where closely spaced vertical joints constitute joint zones that erode to form regularly spaced half kilometer slot canyons striking 351 between these joint zones is a set of isolated joints striking 339 fracture interaction and horsetail wing crack development indicate that the 339 striking joint set is younger than the 351 striking joint zones despite the lateral extent of stress reduction shadows in the vicinity of the large scale joint zones in addition to an older less pervasive 020 joint set this sequence of jointing records a counterclockwise rotation of the regional extension directed from wnw to wsw in the navajo sandstone at znp znp is located at the western margin of the colorado plateau 100 km east of the major normal faults of the northeastern central basin and range subprovince extension within the eastern central basin and range initiated during the miocene and exhibited a wsw extension direction anderson 1971 wernicke et al 1988 snow and wernicke 2000 the correlation between nearby basin and range extension and the extension direction for the 351 tending joint zones of znp is so close that the jointing at znp is interpreted as evidence for modest yet pervasive basin and range extension in the western margin of the colorado plateau

a probabilistic approach for landslide hazard analysis abstract we present a general framework for probabilistic landslide hazard analysis with respect to other quantitative hazard assessment approaches this probabilistic landslide hazard analysis has the advantage to provide hazard curves and maps and to be applicable to all typologies of landslides if necessary accounting for both their onset and transit probability the method quantifies for a given slope location the exceedance probability of being affected by a landslide with a specific local intensity within a reference time interval i e the hazard curve under the common assumption that landslides behave as a poisson process hazard maps are calculated reducing the hazard curve to single values by choosing a fixed probability of exceedance following standards or regulation requirements the method is based on the assessment of a landslide onset frequency a runout frequency for long runout landslides and the local definition of landslide intensity which can be expressed through different parameters according to landslide typology for long runout landslides the runout and spatially varying intensity and uncertainty are considered hazard curves and maps play a fundamental role in the design and dimensioning of mitigation structures in land planning and in the definition of risk and hazard management policies starting from the general framework we apply the methodology for rockfall hazard analysis and we test it in an area affected by the christchurch 2011 earthquake new zealand which triggered a large number of rockfalls killing five people

comparing the performance of trigrs and tivass in spatial and temporal prediction of rainfall induced shallow landslides this study compares the performance of transient rainfall infiltration and grid based regional slope stability trigrs model and time variant slope stability tivass model in the prediction of rainfall induced shallow landslides trigrs employs one dimensional 1 d subsurface flow to simulate the infiltration rate whereas a three dimensional 3 d model is utilized in tivass the former has been widely used in landslide modeling while the latter was developed only recently both programs are used for the spatiotemporal prediction of shallow landslides caused by rainfall this study uses the july 2011 landslide event that occurred in mt umyeon seoul korea for validation the performance of the two programs is evaluated by comparison with data of the actual landslides in both location and timing by using a landslide ratio for each factor of safety class text lr text class index which was developed for addressing point like landslide locations moreover the influence of surface flow on landslide initiation is assessed the results show that the shallow landslides predicted by the two models are highly consistent with those of the observed sliding sites although the performance of tivass is slightly better overland flow affects the buildup of the pressure head and reduces the slope stability although this influence was not significant in this case a slight increase in the predicted unstable area from 19 30 to 19 93 was recorded when the overland flow was considered it is concluded that both models are suitable for application in the study area however although it is a well established model requiring less input data and shorter run times trigrs produces less accurate results

prediction of rainfall induced shallow landslides in the loess plateau yan an china using the trigrs model in this work a transient rainfall infiltration and grid based regional slope stability model trigrs was implemented in a case study of yan an city northwest china in this area widespread shallow landslides were triggered by the 12 july 2013 exceptional rainstorm event a high resolution dem soil parameters from in situ and laboratory measurements water table depths the maximum depth of precipitation infiltration and rain gauge corrected precipitation of the event were used as inputs in the trigrs model shallow landslides triggered on the same day were used to evaluate the modeling results the summarized results are as follows i the characteristics and distribution of thirty five shallow landslides triggered by the 12 july 2013 rainfall event were identified in the study area and all were classified as shallow landslides with the maximum depth area and volume less than 3 m 200 m2 and 1000 m3 respectively ii four intermediate factor of safety fs maps were generated using the trigrs model to represent the scenarios 6 12 18 and 24 hours after the storm event the area with fs 1 increased with the rainfall duration the percentage of the area with fs 1 was 0 2 3 3 3 8 and 5 1 for the four stages respectively twenty four hours after the rainstorm trigrs predicted that 1255 grid cells failed which is consistent with the field data iii trigrs generated more satisfactory results at a given precipitation threshold than sinmap which is ideal for landslide hazard zoning for land use planning at the regional scale comparison results showed that trigrs is more useful for landslide prediction for a certain precipitation threshold also in the regional scale iv analysis of the responses of loess slope prone to slope failure after different precipitation scenarios revealed that loess slopes are particularly sensitive to extended periods of heavy precipitation copyright 2016 john wiley sons ltd

a hybrid feature selection algorithm integrating an extreme learning machine for landslide susceptibility modeling of mt woomyeon south korea abstract an ever increasing trend of extreme rainfall events in south korea owing to climate change is causing shallow landslides and debris flows in mountains that cover 70 of the total land area of the nation these catastrophic gravity driven processes cost the government several billion krw south korean won in losses in addition to fatalities every year the most common type of landslide observed is the shallow landslide which occurs at 1 3 m depth and may mobilize into more catastrophic flow type landslides hence to predict potential landslide areas susceptibility maps are developed in a geographical information system gis environment utilizing available morphological hydrological geotechnical and geological data landslide susceptibility models were developed using 163 landslide points and an equal number of nonlandslide points in mt woomyeon seoul and 23 landslide conditioning factors however because not all of the factors contribute to the determination of the spatial probability for landslide initiation and a simple filter or wrapper based approach is not efficient in identifying all of the relevant features a feedback loop based hybrid algorithm was implemented in conjunction with a learning scheme called an extreme learning machine which is based on a single layer feed forward network validation of the constructed susceptibility model was conducted using a testing set of landslide inventory data through a prediction rate curve the model selected 13 relevant conditioning factors out of the initial 23 and the resulting susceptibility map shows a success rate of 85 and a prediction rate of 89 45 indicating a good performance in contrast to the low success and prediction rate of 69 19 and 56 19 respectively as obtained using a wrapper technique

an advanced process based distributed model for the investigation of rainfall induced landslides the effect of process representation and boundary conditions extreme rainfall events are the major driver of shallow landslide occurrences in mountainous and steep terrain regions around the world subsurface hydrology has a dominant role on the initiation of rainfall induced shallow landslides since changes in the soil water content affect significantly the soil shear strength rainfall infiltration produces an increase of soil water potential which is followed by a rapid drop in apparent cohesion especially on steep slopes of shallow soils this loss of shear strength can lead to failure even in unsaturated conditions before positive water pressures are developed we present hydrolisthisis a process based model fully distributed in space with fine time resolution in order to investigate the interactions between surface and subsurface hydrology and shallow landslides initiation fundamental elements of the approach are the dependence of shear strength on the three dimensional 3 d field of soil water potential as well as the temporal evolution of soil water potential during the wetting and drying phases specifically 3 d variably saturated flow conditions including soil hydraulic hysteresis and preferential flow phenomena are simulated for the subsurface flow coupled with a surface runoff routine based on the kinematic wave approximation the geotechnical component of the model is based on a multidimensional limit equilibrium analysis which takes into account the basic principles of unsaturated soil mechanics a series of numerical simulations were carried out with various boundary conditions and using different hydrological and geotechnical components boundary conditions in terms of distributed soil depth were generated using both empirical and process based models the effect of including preferential flow and soil hydraulic hysteresis was tested together with the replacement of the infinite slope assumption with the multidimensional limit equilibrium analysis the results show that boundary conditions play a crucial role in the model performance and that the introduced hydrological preferential flow and soil hydraulic hysteresis and geotechnical components multidimensional limit equilibrium analysis significantly improve predictive capabilities in the presented case study