time reverse imaging for far field tsunami forecasting 2011 tohoku earthquake case study this paper describes a new method for forecasting far field tsunamis by combining aspects of least squares tsunami source inversion lsq with time reverse imaging tri this method has the same source representation as lsq but uses tri to estimate initial sea surface displacement we apply this method to the 2011 japan tsunami and the results show that the method produces tsunami waveforms of excellent agreement with observed waveforms at both near and far field stations not used in the source estimation the spatial distribution of cumulative sea surface displacement agrees well with other models obtained in more sophisticated inversions but resolve source kinematics are not well resolved the method has potential for application in tsunami warning systems as it is computationally efficient and can be used to estimate the initial source model by applying precomputed green s functions in order to provide more accurate and realistic tsunami predictions

tsunami simulation method assimilating ocean bottom pressure data near a tsunami source region a new method was developed to reproduce the tsunami height distribution in and around the source area at a certain time from a large number of ocean bottom pressure sensors without information on an earthquake source a dense cabled observation network called s net which consists of 150 ocean bottom pressure sensors was installed recently along a wide portion of the seafloor off kanto tohoku and hokkaido in japan however in the source area the ocean bottom pressure sensors cannot observe directly an initial ocean surface displacement therefore we developed the new method the method was tested and functioned well for a synthetic tsunami from a simple rectangular fault with an ocean bottom pressure sensor network using 10 arc min or 20 km intervals for a test case that is more realistic ocean bottom pressure sensors with 15 arc min intervals along the north south direction and sensors with 30 arc min intervals along the east west direction were used in the test case the method also functioned well enough to reproduce the tsunami height field in general these results indicated that the method could be used for tsunami early warning by estimating the tsunami height field just after a great earthquake without the need for earthquake source information

successive estimation of a tsunami wavefield without earthquake source data a data assimilation approach toward real time tsunami forecasting we propose a tsunami forecasting method based on a data assimilation technique designed for dense tsunameter networks rather than using seismic source parameters or initial sea surface height as the initial condition of for a tsunami forecasting it estimates the current tsunami wavefield tsunami height and tsunami velocity in real time by repeatedly assimilating dense tsunami data into a numerical simulation numerical experiments were performed using a simple 1 d station array and the 2 d layout of the new s net tsunameter network around the japan trench treating a synthetic tsunami calculated by the finite difference method as observed data the data assimilation reproduced the assumed tsunami wavefield before the tsunami struck the coastline because the method estimates the full tsunami wavefield including velocity these wavefields can be used as initial conditions for other tsunami simulations to calculate inundation or runup for real time forecasting

medium scale earthflow susceptibility modelling by remote sensing and geographical information systems based multivariate statistics approach an example from northeastern turkey the aim of the present study was to produce an earthflow susceptibility map for the city center and environs of the province of rize located at the northeastern part of turkey the study area is the rainiest region of turkey and due to the triggering effect of precipitation earthflows are frequently observed in and around the study area besides this point weathered rock units and steep topography accompany with precipitation for the occurrence of earthflow cases considering this point an earthflow susceptibility mapping was inferred to be a necessity for the area parameters such as lithology slope gradient slope aspect topographical wetness index twi stream power index spi slope curvature and sediment capacity index ls were considered to be earthflow conditioning parameters a multi temporal earthflow inventory map for a period of 4 years 2011 2015 was initially generated by way of remote sensing approach and field surveys earthflow susceptibility map was produced using the logistic regression method after which the produced susceptibility map was validated the mapped earthflows were separated into two groups prior to modelling and validation the first group was for training and the second group was for validation steps the accuracy of the model was measured by fitting them to a validation set of mapped earthflows area under curvature auc approach was applied for validation purposes the prediction capability of the earthflow susceptibility map produced can be regarded as acceptable in accordance with the auc values of 0 62 for the logistic regression model based on these results the obtained earthflow susceptibility map can be used to mitigate hazards related to landslides and to aid in land use planning for the rize city center

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

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

qualitative landslide susceptibility assessment by multicriteria analysis a case study from san antonio del sur guantanamo cuba geomorphological information can be combined with decision support tools to assess landslide hazard and risk a heuristic model was applied to a rural municipality in eastern cuba the study is based on a terrain mapping units tmu map generated at 1 50 000 scale by interpretation of aerial photos satellite images and field data information describing 603 terrain units was collected in a database landslide areas were mapped in detail to classify the different failure types and parts three major landslide regions are recognized in the study area coastal hills with rockfalls shallow debris flows and old rotational rockslides denudational slopes in limestone with very large deep seated rockslides related to tectonic activity and the sierra de caujeri scarp with large rockslides the caujeri scarp presents the highest hazard with recent landslides and various signs of active processes the different landforms and the causative factors for landslides were analyzed and used to develop the heuristic model the model is based on weights assigned by expert judgment and organized in a number of components such as slope angle internal relief slope shape geological formation active faults distance to drainage distance to springs geomorphological subunits and existing landslide zones from these variables a hierarchical heuristic model was applied in which three levels of weights were designed for classes variables and criteria the model combines all weights into a single hazard value for each pixel of the landslide hazard map the hazard map was then divided by two scales one with three classes for disaster managers and one with 10 detailed hazard classes for technical staff the range of weight values and the number of existing landslides is registered for each class the resulting increasing landslide density with higher hazard classes indicates that the output map is reliable the landslide hazard map was used in combination with existing information on buildings and infrastructure to prepare a qualitative risk map the complete lack of historical landslide information and geotechnical data precludes the development of quantitative deterministic or probabilistic models

preparing for the future nankai trough tsunami a data assimilation and inversion analysis from various observational systems the future nankai trough tsunami is one of the imminent threats to the japanese coastal communities that could potentially cause a catastrophic event as a part of the countermeasure efforts for such an occurrence this study analyzes the efficacy of combining tsunami data assimilation da and waveform inversion wi the da is used to continuously refine a wave field model whereas the wi is used to estimate the tsunami source we consider a future scenario of the nankai trough tsunami recorded at various observational systems including ocean bottom pressure obp gauges global positioning system gps buoys and ship height positioning data since most of the obp gauges are located inside the source region the recorded tsunami signals exhibit significant offsets from surface measurements due to coseismic seafloor deformation effects such biased data are not applicable to the standard da but can be taken into account in the wi on the other hand the use of wi for the ship data may not be practical because a considerably large precomputed tsunami database is needed to cope with the spontaneous ship locations the da is more suitable for such an observational system as it can be executed sequentially in time and does not require precomputed scenarios therefore the combined approach of da and wi allows us to concurrently make use of all observational resources additionally we introduce a bias correction scheme for the obp data to improve the accuracy and an adaptive thinning of observations to determine the efficient number of observations

linked 3 d modelling of megathrust earthquake tsunami events from subduction to tsunami run up e h m t u and a a g acknowledge additional support by the german research foundation dfg projects no ga 2465 2 1 ga 2465 3 1 by bacatec project no a4 and baylat by konwihr the bavarian competence network for technical and scientific high performance computing project newwave by kaust crg gast grant no ors 2016 crg5 3027 and fragen grant no ors 2017 crg6 3389 02 by the european union s horizon 2020 research and innovation program exahype grant no 671698 cheese grant no 823844 and tear grant no 852992

a methodology for near field tsunami inundation forecasting application to the 2011 tohoku tsunami existing tsunami early warning systems in the world can give either one or a combination of estimated tsunami arrival times heights or qualitative tsunami forecasts before the tsunami hits near field coastlines a future tsunami early warning system should be able to provide a reliable near field tsunami inundation forecast on high resolution topography within a short time period here we describe a new methodology for near field tsunami inundation forecasting in this method a precomputed tsunami inundation and precomputed tsunami waveform database is required after information about a tsunami source is estimated tsunami waveforms at nearshore points can be simulated in real time a scenario that gives the most similar tsunami waveforms is selected as the site specific best scenario and the tsunami inundation from that scenario is selected as the tsunami inundation forecast to test the algorithm tsunami inundation along the sanriku coast is forecasted by using source models for the 2011 tohoku earthquake estimated from gps w phase or offshore tsunami waveform data the forecasting algorithm is capable of providing a tsunami inundation forecast that is similar to that obtained by numerical forward modeling but with remarkably smaller cpu time the time required to forecast tsunami inundation in coastal sites from the sendai plain to miyako city is approximately 3 min after information about the tsunami source is obtained we found that the tsunami inundation forecasts from the 5 min gps 5 min w phase 10 min w phase fault models and 35 min tsunami source model are all reliable for tsunami early warning purposes and quantitatively match the observations well although the latter model gives tsunami forecasts with highest overall accuracy the required times to obtain tsunami forecast from the above four models are 8 min 9 min 14 min and 39 min after the earthquake respectively or in other words 3 min after receiving the source model this method can be useful in developing future tsunami forecasting systems with a capability of providing tsunami inundation forecasts for locations near the tsunami source area

globally scattered 2011 tohoku tsunami waves from a seafloor sensor array in the northeast pacific ocean modeling of tsunami wave propagation for forecasting focuses on the arrival time and amplitude of the earliest tsunami waves reaching coastlines the complex later tsunami wavefield in which scattering is predominant poses additional hazards due to possible constructive interference of coherent packets of wave energy however almost no datasets exist to characterize the geographical sources and temporal evolution of the scattered waves here we show how recordings of the 2011 tohoku tsunami by an array of pressure gauge sensors in the northeastern pacific ocean reveal coherent waves that are produced by scattering from distant coastlines including south america and antarctica as well as multiple seafloor fracture zones ridges and island chains multiple signal classification analysis and backward propagation ray tracing provide tight constraints on the origin of each scattered phase and resolve simultaneous wave arrivals from different scatterers incoming waves from constant back azimuths occur over time durations of several hours revealing the time persistence of specific geographical scatterers the results can advance numerical predictions of tsunami wave impact because they provide direct evidence for the necessity of incorporating both local and distant bathymetry over a range of length scales and for long time durations to account for the azimuthal dependence of scatterer strength

tsunami speed variations in density stratified compressible global oceans 1 tsunami speed variations in the deep ocean caused by seawater density stratification is investigated using a newly developed propagator matrix method that is applicable to seawater with depth variable sound speeds and density gradients for a 4 km deep ocean the total tsunami speed reduction is 0 44 compared with incompressible homogeneous seawater two thirds of the reduction is due to elastic energy stored in the water and one third is due to water density stratification mainly by hydrostatic compression tsunami speeds are computed for global ocean density and sound speed profiles and characteristic structures are discussed tsunami speed reductions are proportional to ocean depth with small variations except in warm mediterranean seas the impacts of seawater compressibility and the elasticity effect of the solid earth on tsunami traveltime should be included for precise modeling of transoceanic tsunamis

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

digital terrain modelling a review of hydrological geomorphological and biological applications the topography of a catchment has a major impact on the hydrological geomorphological and biological processes active in the landscape the spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques many geographic information systems are being developed that store topographic information as the primary data for analysing water resource and biological problems furthermore topography can be used to develop more physically realistic structures for hydrologic and water quality models that directly account for the impact of topography on the hydrology digital elevation models are the primary data used in the analysis of catchment topography we describe elevation data sources digital elevation model structures and the analysis of digital elevation data for hydrological geomorphological and biological applications some hydrologic models that make use of digital representations of topography are also considered

a response function approach for rapid far field tsunami forecasting predicting tsunami impacts at remote coasts largely relies on tsunami en route measurements in an open ocean in this work these measurements are used to generate instant tsunami predictions in deep water and near the coast the predictions are generated as a response or a combination of responses to one or more tsunameters with each response obtained as a convolution of real time tsunameter measurements and a pre computed pulse response function prf practical implementation of this method requires tables of prfs in a 3d parameter space earthquake location tsunameter forecasted site examples of hindcasting the 2010 chilean and the 2011 tohoku oki tsunamis along the us west coast and beyond demonstrated high accuracy of the suggested technology in application to trans pacific seismically generated tsunamis

a comparison of the gis based landslide susceptibility assessment methods multivariate versus bivariate the purpose of this study is to evaluate and to compare the results of multivariate logical regression and bivariate landslide susceptibility methods in geographical information system gis based landslide susceptibility assessment procedures in order to achieve this goal the asarsuyu catchment in nw turkey was selected as a test zone because of its well known landslide occurrences interfering with the e 5 highway mountain pass

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

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

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

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

a tsunami warning system based on offshore bottom pressure gauges and data assimilation for crete island in the eastern mediterranean basin the eastern mediterranean basin emb is under the threat of tsunami events triggered by various causes including earthquakes and landslides we propose a deployment of offshore bottom pressure gau

spatial prediction of landslide hazard at the luxi area china using support vector machines the main objective of this study is to investigate the potential application of gis based support vector machines svm with four kernel functions i e radial basis function rbf polynomial pl sigmoid sig and linear ln for landslide susceptibility mapping at luxi city in jiangxi province china at the first stage of the study a landslide inventory map with 282 landslide locations was identified using aerial photographs satellite images and field surveys of this 70 of the landslides 196 landslide locations are used as a training dataset and the rest 86 landslide locations were used as the validation dataset then 15 landslide conditioning factors were prepared i e altitude aspect slope stream power index spi topographic wetness index twi sediment transport index sti plan curvature profile curvature distance from river distance from road distance from fault lithology land use ndvi and rainfall using these conditioning factors landslide susceptibility indexes were calculated using svm with the four kernel functions subsequently the results were exported and plotted in arcgis and four landslide susceptibility maps were produced the four susceptibility maps were validated and compared using the landslide locations and the success rate and prediction rate methods the validation results showed that success rates for the four svm models are 82 0 rbf 83 0 pl 45 0 sig and 70 0 ln the prediction rates for the four svm models are 81 0 rbf 71 0 pl 40 0 sig and ln 63 0 sig the result shows that the rbf svm model has the highest overall performance the produced susceptibility maps may be useful for general land use planning in landslides

gis based landslide susceptibility for arsin yomra trabzon north turkey region the purpose of this study is to assess the susceptibility of landslides around yomra and arsin towns near trabzon in northeast of turkey using a geographical information system gis landslide inventory of the area was made by detailed field surveys and the analyses of the topographical map the landslide triggering factors are considered to be slope angle slope aspect distance from drainage distance from roads and the weathered lithological units which were called as geotechnical units in the study idrisi and arcgis packages manipulated all the collected data logistic regression lr and weighted linear combination wlc statistical methods were used to create a landslide susceptibility map for the study area the results were assessed within the scope of two different points a effectiveness of the methods used and b effectiveness of the environmental casual parameters influencing the landslides the results showed that the wlc model is more suitable than the lr model regarding the casual parameters geotechnical units and slopes were found to be the most important variables for estimating the landslide susceptibility in the study area

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

synthesizing ocean bottom pressure records including seismic wave and tsunami contributions toward realistic tests of monitoring systems the present study proposes a method for synthesizing the ocean bottom pressure records during a tsunamigenic earthquake firstly a linear seismic wave simulation is conducted with a kinematic earthquake fault model as a source then a nonlinear tsunami simulation is conducted using the sea bottom movement calculated in the seismic wave simulation by using these simulation results this method can provide realistic ocean bottom pressure change data including both seismic and tsunami contributions a simple theoretical consideration indicates that the dynamic pressure change caused by the sea bottom acceleration can contribute significantly until the duration of 90 s for a depth of 4000 m in the ocean the performance of a tsunami monitoring system was investigated using the synthesized ocean bottom pressure records it indicates that the system based on the hydrostatic approximation could not measure the actual tsunami height when the time does not elapse enough the dynamic pressure change and the permanent sea bottom deformation inside the source region break the condition of a simple hydrostatic approximation a tsunami source estimation method of tfish is also examined even though the synthesized records contain a large dynamic pressure change which is not considered in the algorithm tfish showed a satisfactory performance when 5 min after the earthquake occurrence the pressure records synthesized in this study including both seismic wave and tsunami contributions are more practical for evaluating the performance of our monitoring ability whereas most tsunami monitoring tests neglect the seismic wave contribution

shallow landslide susceptibility assessment in a semiarid environment a quaternary catchment of kwazulu natal south africa abstract this paper presents an evaluation of landslide susceptibility maps based on the frequency ratio fr landslide susceptibility index lsi logistic regression lr and artificial neural network ann methods applied within a quaternary catchment in the kwazulu natal region south africa landslide occurrence in this particular catchment is generally induced by heavy rainfall events where shallow landslips occur mostly on steep slopes thereby threatening informal housing at the base of slopes the scope of this study is to compare the performance of landslide susceptibility models and rate the importance of landslide causal factors thirteen landslide causal factors including altitude slope angle aspect slope total curvature slope plan curvature slope profile curvature proximity to stream network topographic wetness index twi lithology land cover proximity to faults proximity to dolerite sills and dykes and proximity to the road network were considered in the study furthermore each causal factor was rated according to the above mentioned methods and it was found that the most influential landslide causal factors are the altitude land cover and lithology the resulting susceptibility maps were classified into 5 classes ranging from very low to very high susceptibility model performance was tested using an independent validation set comprising 10 of all mapped landslides for verification of the models performance receiver operating curves rocs were calculated and the areas under curve auc for the success rate curves were 0 736 0 748 0 827 and 0 809 for fr lsi lr and ann respectively the findings revealed that models showed promising results for shallow landslide susceptibility modelling since they all give accuracy values higher than 73 the lr and ann methods however proved to be superior in representing landslide susceptibility throughout the study area

tsunami data assimilation of cascadia seafloor pressure gauge records from the 2012 haida gwaii earthquake we use tsunami waveforms recorded on a dense array of seafloor pressure gauges offshore oregon and california from the 2012 haida gwaii canada earthquake to simulate the performance of two different real time tsunami forecasting methods in the first method the tsunami source is first estimated by inversion of recorded tsunami waveforms in the second method the array data are assimilated to reproduce tsunami wavefields these estimates can be used for forecasting tsunami on the coast the dense seafloor array provides critical data for both methods to produce timeliness 30 min lead time and accuracy in both timing and amplitude 94 confidence tsunami forecasts real time tsunami data on dense arrays and data assimilation can be tested as a possible new generation tsunami warning system

synthesizing sea surface height change including seismic waves and tsunami using a dynamic rupture scenario of anticipated nankai trough earthquakes abstract the development of offshore observation technology will provide researchers with tsunami records from within an earthquake focal area but this will create new problems because seismic waves coexist with tsunami inside a focal area the seismic waves could act as noise for the tsunami signal this study shows an efficient method to calculate sea surface height change caused by an earthquake including both seismic waves and tsunami simulation results indicate that seismic waves overlap with tsunami both affect the change in sea surface height although most previous tsunami studies have neglected the contribution of seismic waves we also numerically simulated the sea surface displacement wavefield and hypothesized results for an anticipated rupture scenario of a huge earthquake that may possibly occur in the nankai trough japan the synthesized record could be used to evaluate the performance of a real time tsunami prediction method additionally we discussed the similarity and difference between two kinds of tsunami waveforms the displacement of the sea surface and the pressure change at the sea bottom although seismic waves appeared in both waveforms the contribution of seismic waves was lower in the displacement at the sea surface than in the pressure change at the sea bottom

traveltime delay and initial phase reversal of distant tsunamis coupled with the self gravitating elastic earth systematic tsunami traveltime delays of up to 15 min relative to the numerically simulated long waves from the 2010 chilean and 2011 tohoku oki earthquakes were widely observed at deep ocean tsunamimeters enigmatic small negative phases appearing before the main peak were commonly found only at the trans oceanic locations the frequency dependence of the measured tsunami phase velocities shows reverse dispersions at long periods i e the tsunami speed becomes slower at periods beyond 1000 s this is consistent with the phase velocities of a tsunami mode coupled with a self gravitating elastic earth suggesting that the effects of compression and dilatation of seawater elastic tsunami loadings on a solid earth and the geopotential variations associated with the motion of mass during tsunami propagation are responsible for the traveltime delays and the initial negative phases simple 1 d tsunami propagation tests confirm that the reverse dispersion creates a small negative phase that precedes the main peak at large distances a new method to simulate tsunami waveforms on real ocean bathymetry that takes into account seawater compressibility the elasticity of the earth and geopotential perturbations has been developed by applying a phase correction to the simulated long waves the simulated waveforms in which phase corrections are applied for the dispersion effects accurately reproduce the observed waveforms including a small initial negative phase that appears at distant locations the traveltime difference between the observed and simulated waveforms has been decreased to less than 5 min and the waveform difference between them remarkably diminishes

near field tsunami forecasting from cabled ocean bottom pressure data 1 we propose a method for near field tsunami forecasting from data acquired by cabled offshore ocean bottom tsunami meters obtms in real time we first invert tsunami waveforms recorded at obtms to estimate the spatial distribution of initial sea surface displacements in the tsunami source region without making any assumptions about fault geometry and earthquake magnitude then we synthesize the coastal tsunami waveforms from the estimated sea surface displacement distribution to improve the reliability of the tsunami forecasting we use updated obtm data to repeat the forecast calculation at 1 min intervals we tested our method by simulating the 1896 sanriku tsunami earthquake which caused a devastating tsunami with maximum runup height of 38 m along the pacific coast of northeastern japan instead of real obtm records proxies were used the simulation demonstrated that our method provided accurate estimations of coastal arrival times and amplitudes of the first peak of the tsunami more than 20 min before the maximum amplitude wave reached the coastal site nearest to the source we also applied the method to real data of a small tsunami that was caused by a local earthquake and successfully forecasted the tsunami at coastal tide stations we found that accuracy of our estimated coastal tsunami amplitudes can be affected by the spatial relationship between the tsunami source and the offshore observation stations our numerical simulation showed that even more accurate tsunami amplitude forecasts would be achieved by deployment of additional offshore stations separated by a distance comparable to the trench parallel length of the tsunami source

real time forecasting of the april 11 2012 sumatra tsunami the april 11 2012 magnitude 8 6 earthquake off the northern coast of sumatra generated a tsunami that was recorded at sea level stations as far as 4800 km from the epicenter and at four ocean bottom pressure sensors darts in the indian ocean the governments of india indonesia sri lanka thailand and maldives issued tsunami warnings for their coastlines the united states pacific tsunami warning center ptwc issued an indian ocean wide tsunami watch bulletin in its role as an interim service provider for the region using an experimental real time tsunami forecast model rift ptwc produced a series of tsunami forecasts during the event that were based on rapidly derived earthquake parameters including initial location and mwp magnitude estimates and the w phase centroid moment tensor solutions w phase cmts obtained at ptwc and at the u s geological survey usgs we discuss the real time forecast methodology and how successive real time tsunami forecasts using the latest w phase cmt solutions improved the accuracy of the forecast

landslide susceptibility assessment in the izmir west anatolia turkey city center and its near vicinity by the logistic regression method a landslide susceptibility assessment for izmir city western turkey which is the third biggest city of turkey was performed by a logistic regression method a database of landslide characteristics was prepared using detailed field surveys the major landslides in the study area are generally observed in the field dominated by weathered volcanics and 39 63 of the total landslide area is in this unit the parameters of lithology slope gradient slope aspect distance to drainage distance to roads and distance to fault lines were used as variables in the logistic regression analysis the effect of each parameter on landslide occurrence was assessed from the corresponding coefficients that appear in the logistic regression function on the basis of the obtained coefficients lithology plays the most important role in determining landslide occurrence and distribution slope gradient has a more significant effect than the other geomorphological parameters such as slope aspect and distance to drainage using a predicted map of probability the study area was classified into five categories of landslide susceptibility very low low moderate high and very high whereas 49 65 of the total study area has very low susceptibility very high susceptibility zones make up 11 69 of the area

tsunami source of the 2011 tohoku oki earthquake japan inversion analysis based on dispersive tsunami simulations 1 the large tsunami of the 2011 tohoku oki earthquake was clearly recorded by the ocean bottom pressure and gps wave gauges deployed in and around japan we estimated the initial tsunami water height distribution by inversion analysis of the waveforms based on dispersive tsunami simulations the distribution is characterized by a peak height of 8 m located near the trench and the high water 2m region extending landward with a width of 100 km a series of numerical simulations suggests that a relatively steep peak located near the trench is necessary in order to simultaneously reproduce the dispersive wave at a far field station and the near field waveforms furthermore we estimated the coseismic slip distribution at the plate boundary which indicates that large slip 30 m occurred at a depth of 20 km which corresponds to a large slip deficit area in the interseismic period another slip 25 m occurred at the shallower part 10 km during the rupture

tsunami waveform inversion including dispersive waves the 2004 earthquake off kii peninsula japan 1 long waves are often assumed to model tsunamis but the wavelength of the initial water height distribution produced by a large submarine earthquake particularly in the direction perpendicular to the fault strike is sometimes not much greater than the water depth the resulting tsunami may have a dispersive character that cannot be simulated based on a conventional long wave approximation the 2004 earthquake off kii peninsula m 7 4 on the southern coast of japan indeed produced a dispersive tsunami that was recorded at two stations located off shikoku for the foreshock m 7 1 on the contrary a dominant dispersive tsunami was not recognized at these stations because dispersive waves show strong directional dependence with respect to the fault strike the above difference indicates that the strikes of the main shock and the foreshock were different we conducted a tsunami waveform inversion analysis based on the dispersive tsunami equations to estimate the initial water height distribution of the main shock the estimated initial water height distribution overlapped with the aftershock region suggesting that the fault strike was perpendicular to the trough axis and the total displaced water volume was 1 7 2 0 109 m3 when we used the conventional long wave approximation the estimated initial water height distribution extended considerably from the aftershock area because artificial sources were needed outside the aftershock area to reproduce the observed dispersive waves

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

fdm simulation of seismic waves ocean acoustic waves and tsunamis based on tsunami coupled equations of motion we have developed a new unified modeling technique for the total simulation of seismic waves ocean acoustic waves and tsunamis resulting from earthquakes based on a finite difference method simulation of the 3d equations of motion using the equilibrium between the pressure gradient and gravity in these equations tsunami propagation is naturally incorporated in the simulation based on the equations of motion the performance of the parallel computation for the newly developed tsunami coupled equations using a domain partitioning procedure shows a high efficiency coefficient with a large number of cpu cores the simulation results show how the near field term associated with seismic waves produced by shallow earthquakes leads to a permanent coseismic deformation of the ground surface which gives rise to the initial tsunami on the sea surface propagation of the tsunami along the sea surface as a gravity wave and ocean acoustic waves in seawater with high frequency multiple p wave reflections between the free surface and sea bottom are also clearly demonstrated by the present simulations we find a good agreement in the tsunami waveform between our results and those obtained by other simulations based on an analytical model and the navier stokes equations demonstrating the effectiveness of the tsunami coupling simulation model based on this simulation we show that the ratio of the amplitude of ocean acoustic waves to the height of the tsunami both of which are produced by the earthquake strongly depends on the rise time of the earthquake rupture this ratio can be used to obtain a more detailed understanding of the source rupture processes of subduction zone earthquakes and for implementing an improved tsunami alert system for slow tsunami earthquakes

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

estimating the effect of earth elasticity and variable water density on tsunami speeds the speed of tsunami waves is typically calculated using the shallow water approximation over a rigid body earth recent comparisons of tsunami arrival times from the 11 march 2011 tsunami suggest however that the standard formulation has errors around the 1 level and it has been suggested that the elasticity of the earth can explain the discrepancy while previous work has indeed shown that such elastic deformation can modify tsunami speeds the effect has been neglected partly due to the difficulty in understanding how large this elastic effect is here we remedy this by providing a new derivation and expression for how to incorporate the first order effect that solid earth elasticity and ocean water compressibility have on tsunami speeds this result is shown to agree approximately with previous theory and helps to explain observed timing discrepancies from the 11 march 2011 tsunami the dispersive elastic correction and the non dispersive compressibility correction together may account for the majority of the observed discrepancy

landslide susceptibility mapping by neuro fuzzy approach in a landslide prone area cameron highlands malaysia this paper presents the results of the neuro fuzzy model using remote sensing data and geographic information system for landslide susceptibility analysis in a part of the cameron highlands areas in malaysia landslide locations in the study area were identified by interpreting aerial photographs and satellite images supported by extensive field surveys landsat tm satellite imagery was used to map the vegetation index maps of the topography lineaments normalized difference vegetation index ndvi and land cover were constructed from the spatial data sets eight landslide conditioning factors such as altitude slope gradient curvature distance from the drainage distance from the road lithology distance from the faults and ndvi were extracted from the spatial database these factors were analyzed using a neuro fuzzy model adaptive neuro fuzzy inference system to produce the landslide susceptibility maps during the model development works a total of five landslide susceptibility models were constructed for verification the results of the analyses were then compared with the field verified landslide locations additionally the receiver operating characteristic curves for all landslide susceptibility models were drawn and the area under curve values were calculated landslide locations were used to validate the results of the landslide susceptibility map and the verification results showed a 97 accuracy for model 5 employing all parameters produced in the present study as the landslide conditioning factors the validation results showed a sufficient agreement between the obtained susceptibility map and the existing data on the landslide areas qualitatively the model yields reasonable results which can be used for preliminary land use planning purposes

tsunami waveform inversion incorporating permanent seafloor deformation and its application to tsunami forecasting 1 we propose a method of tsunami waveform inversion to accurately estimate a tsunami source by incorporating the effect of permanent seafloor deformation recorded by ocean bottom pressure gauges obpgs within the source region we developed a general expression of water depth fluctuation recorded at an obpg following seafloor deformation of arbitrary spatiotemporal distribution by assuming that coseismic rupture propagates with infinite velocity the general expression can be reduced to an equation relating observed obpg waveforms to initial sea surface displacement at the source by using a green s function consisting of two terms the green s function used in regular tsunami inversion and a correction term to account for water depth change in response to permanent seafloor deformation by using the two term green s functions the effect of seafloor deformation can be taken into account in tsunami source estimation we applied the revised inversion method to observations of coseismic seafloor deformation and tsunami during the 2003 tokachi oki earthquake mw 8 3 at two obpg stations near the kuril trench the tsunami source model we estimated is consistent with models previously derived using various other geophysical data sets furthermore the coastal tsunami waveforms we modeled match the observed tsunami well forecasts of tsunami arrival times and first peak amplitudes by our method can be obtained 20 min after an earthquake and can be provided to the coastal communities nearest to the source with a lead time of 10 min

micro tsunami from a local interplate earthquake detected by cabled offshore tsunami observation in northeastern japan a micro tsunami from an interplate earthquake mw 6 1 was observed in 1998 on ocean bottom tsunami meters obtms deployed east off the northeastern japan the offshore tsunami data without complex distortions due to the coastal topography enable us to estimate reliable tsunami source parameters the observed amplitude was about 1 5 cm at epicentral distance less than 100 km we numerically computed the tsunami waveform by solving the linear boussinesq equations the observed tsunami waveforms are well explained by synthetic waveforms assuming the fault width of 10 15 km the depth of the fault is estimated as 5 10 km below the seafloor which is in good agreement with the location of the plate boundary defined by previous seismic studies

surface wave tomography from microseisms in southern california received 5 april 2005 revised 23 may 2005 accepted 9 june 2005 published 26 july 2005 1 since it has already been demonstrated that point topoint seismic propagation green functions can be extracted from seismic noise it should be possible to image earth structure using the ambient noise field seismic noise data from 148 broadband seismic stations in southern california were used to extract the surface wave arrival times between all station pairs in the network the seismic data were then used in a simple but densely sampled tomographic procedure to estimate the surface wave velocity structure within the frequency range of 0 1 0 2 hz for a region in southern california the result compares favorably with previous estimates obtained using more conventional and elaborate inversion procedures this demonstrates that coherent noise field between station pairs can be used for seismic imaging purposes citation sabra k g p gerstoft p roux w a kuperman and m c fehler 2005 surface wave tomography from microseisms in southern california geophys res lett 32 l14311 doi 10 1029 2005gl023155

landslide hazard mapping based on geological attributes abstract a landslide susceptibility zoning technique is proposed and has been tested in a catchment area of 317 km 2 along the aglar river a tributary of the river yamuna in the himalayas the aglar catchment is characterised by varied rock types mostly sedimentary an active fault landslides moderate to intense seismic activity and moderate human influence very little is known about this terrain except for one previous study this study focusses on the relationship between the terrain parameters and landslide hazard mapping a landslide susceptibility map is presented which can serve as first generation map on which subsequent detailed information can be incorported it is the first map of this kind from the himalayas based on quantitative evaluation of geomorphological and geological parameters on a classified terrain database map the study is in two stages first the terrain has been classified into several homogeneous patterns followed by small physiographic units which are uniform in their characteristics throughout second each unit acquires a score from a rating system based on the degree of mutual relationship between landslides and geological attributes such as slope distance from fault relief dip slope relationship etc each of which has been given weighting according to the strength of this relationship the aim is to frame a practical database system rationally which can be imported into a geographical information system for rapid digital handling of the data a positive relationship established between landslide and sediment yield indicates that long term sediment production in the catchment area comes from the ongoing geological and geomorphological activity the work may have applications in various parts of the himalayas especially the ungauged and unknown catchments falling in similar geological areas and latitudes

the effect of the sampling strategies on the landslide susceptibility mapping by conditional probability and artificial neural networks this study presented herein compares the effect of the sampling strategies by means of landslide inventory on the landslide susceptibility mapping the conditional probability cp and artificial neural networks ann models were applied in sebinkarahisar giresun turkey digital elevation model was first constructed using a geographical information system software and parameter maps affecting the slope stability such as geology faults drainage system topographical elevation slope angle slope aspect topographic wetness index stream power index and normalized difference vegetation index were considered in the last stage of the analyses landslide susceptibility maps were produced applying different sampling strategies such as scarp seed cell and point the maps elaborated were then compared by means of their validations scarp sampling strategy gave the best results than the point whereas the scarp and seed cell methods can be evaluated relatively similar comparison of the landslide susceptibility maps with known landslide locations indicated that the higher accuracy was obtained for ann model using the scarp sampling strategy the results obtained in this study also showed that the cp model can be used as a simple tool in assessment of the landslide susceptibility because input process calculations and output process are very simple and can be readily understood

green s function based tsunami data assimilation a fast data assimilation approach toward tsunami early warning we propose a new tsunami data assimilation approach based on green s functions to reduce the computation time for tsunami early warning green s function based tsunami data assimilation gftda forecasts the waveforms at points of interest pois by superposition of green s functions between observation stations and pois unlike the previous assimilation approach gftda does not require the calculation of the tsunami wavefield for the whole region during the assimilation process because the green s functions have been calculated in advance the forecasted waveforms can be calculated by a simple matrix manipulation the application to the tsunami waveforms recorded by the bottom pressure gauges of the cascadia initiative from the 2012 haida gwaii earthquake reveals that gftda achieves the same accuracy as the previous assimilation approach while reducing the time required to issue a valid tsunami warning

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

love and rayleigh phase velocity maps 5 40 s of the western and central usa from usarray data abstract continuous data recorded on more than 1600 usarray seismic stations operating in the western and central us between 2006 and 2012 are used to map phase velocities of love and rayleigh waves at short periods 5 40 s using a noise correlation technique vertical and transverse records for all station pairs separated by less than 600 km are cross correlated in 4 h long segments and the resulting spectra are stacked for the time period of station operation dispersion curves are determined from the locations of zeros in the real component of the correlation spectra using a method based on that of aki 1957 phase velocity maps expanded on a 0 25 by 0 25 pixel grid are estimated by inversion of the phase velocity measurements comparison with predicted phase velocity maps based on the crustal model crust2 0 combined with the mantle model nd08 shows good agreement at the longer periods strong slow anomalies 25 in the short period maps are geographically correlated with basins and regions of thick sedimentary cover the strength of these anomalies is not well predicted by existing crustal velocity models

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

landslide processes and landslide susceptibility analysis from an upland watershed a case study from st andrew jamaica west indies abstract rainfall induced landslides are common geomorphic events on the steeper slopes of upper st andrew and cause severe environmental engineering social and economic repercussions in the area a geotechnical study was initiated to identify a past present and potential landslide types and sites for landslides b to examine the nature of geological geomorphological and geotechnical conditions under which failures can take place and c the potential landslide hazard in the area 886 failures were mapped more than 80 of which were located in soils a total of 1 55 km2 9 80 of the total area had failed approximately 59 failures per km2 were mapped with the highest density within elastic sedimentary units and weathered granodiorite 789 failure were mapped on slopes between 20 45 with no failure on slope less than 10 481 failures were mapped along twelve major roadways 46 6 km of road with approximately 10 failures km of road analysis of eighteen geotechnical units within nine geological formations revealed that the highest susceptibility for failure was within old landslide deposits with granular nonplastic to low plasticity soils and on slopes between 20 and 30 the lowest susceptibility was found within white limestones and recent alluvium and terrace deposits granular nonplastic to low plasticity soils are generally more susceptible than fine soils especially on slopes between 30 and 45 while granular and expansive clay soils demonstrate similar susceptibilities but on slopes between 30 and 45 and 20 and 45 respectively clastic sedimentary rocks are more susceptible that igneous lithologies an increase in slope angle increases the susceptibility to failures but only on slopes up to 45 an increase in the degree of weathering of soils and bedrock and fracturing of bedrock as well as road construction increases the landslide susceptibility in the area

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

near field tsunami inundation forecast using the parallel tunami n2 model application to the 2011 tohoku oki earthquake combined with source inversions to contribute to tsunami early warning systems we investigated the currently achievable speed of tsunami inundation simulations on a parallel computer as well as the benefits of high resolution and faster than real time inundation predictions we found that a 5 m resolution inundation simulation can be 75 times faster than real time requiring only 1 5 min to overview the inundation situation in sendai city for the 2011 tohoku tsunami we developed a novel parallel tsunami model based on the well known tunami n2 model and achieved 9 17 tera floating point operations per second flops on 9469 cpu cores the present model can accurately hindcast the observed inundated regions of the 2011 tohoku tsunami using tsunami source estimations of the tfish and tfish rapid algorithms which can be instantly derived from real time observation data the present high resolution predictions can provide clear images of imminent hazards disasters and can provide guidance for appropriate evacuation actions

seismic and tsunami wave propagation of the 2011 off the pacific coast of tohoku earthquake as inferred from the tsunami coupled finite difference simulation abstract the 2011 tohoku earthquake m 9 0 caused significant hazards including strong ground motion coseismic ground deformation and tsunamis for a deeper understanding of these phenomena we conducted a large scale parallel computer simulation by means of the finite difference method fdm with newly developed tsunami coupled equations of motion this method is based on the equations of motion for an elastic medium treating seawater as elastic material having zero s wave velocity tsunami waves are included by taking into account gravity and their equilibrium with the pressure gradient an effective method of fdm simulation using the state of the art massively parallelized k computer is also studied with the use of a 3d layered velocity structure that includes topography and bathymetry basement structure moho depth and plate boundaries and use of the appropriate source rupture model based on joint inversion of seismic waves and geodetic observations the simulated seismic waves demonstrate anomalous seismic wave propagation by the thick 3d basin structure inland we also found that the sea column acts as a strong absorber of seismic waves for shallow up dip slip on the ocean side coseismic deformation and tsunamis are dynamically generated in this simulation tsunami attacks on the subsided pacific coast are simulated without any additional assumptions we also modeled the tsunami and seismic records of ocean bottom pressure gauges above the fault because sea bottom tsunami and seismic observation is powerful but very complex recording both seismic and tsunami waves the use of these coupled numerical simulations has great potential for resolving complex source fault rupture processes in a 3d heterogeneous structure online material mpeg movies of fault slip seismic wave propagation seafloor and ground displacement and tsunamic propagation

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