geology and geomorphology control suspended sediment yield and modulate increases following timber harvest in temperate headwater streams abstract suspended sediment transport is an important contributor to ecologic and geomorphic functions of streams however it is challenging to generalize predictions of sediment yield because it is influenced by many factors in this study we quantified the relevance of natural controls e g geology catchment physiography on suspended sediment yield ssy in headwater streams managed for timber harvest we collected and analyzed six years of data from 10 sites five headwater sub catchments and five watershed outlets in the trask river watershed western oregon united states we used generalized least squares regression models to investigate how the parameters of the ssy rating curve varied as a function of catchment setting and whether the setting modulated the ssy response to forest harvesting results indicated that the highest intercepts of the power relation between unit discharge and ssy were associated with sites underlain primarily by friable rocks e g sedimentary formations the greatest increases in ssy after forest harvesting up to an order of magnitude also occurred at sites underlain by the more friable lithologies in contrast basins underlain by resistant lithologies intrusive rocks had lower ssy and were more resilient to management related increases in ssy as such the impact of forest management activities e g use of forested buffers building of new roads on the variability in ssy was primarily contingent on catchment lithology sites with higher ssy or harvest related increases in ssy also generally had a lower mean elevation and slope b greater landscape roughness and c lower sediment connectivity we used principal component analysis pca to further explore the relationship between ssy and several basin physiographic variables the pca clearly separated sites underlain by friable geologic units from those underlain by resistant lithologies results are consistent with greater rates of weathering and supply of sediment to headwater streams in catchments with more friable lithologies and limited sediment supply in catchments underlain by resistant lithologies we hypothesize that a similar framework may aid in predicting the overall ssy of a catchment as well as its susceptibility to increases in ssy following forest harvesting

supply and removal of sediment in a landslide dominated mountain belt central range taiwan abstract a strong coupling between hillslope and valley systems is often inferred for mountain landscapes dominated by bedrock landsliding we reveal the nature of this link using data sets on landsliding and sediment transport from two montane catchments draining the eastern central range of taiwan here the magnitude frequency distribution of landslides can be modeled by a robust power law but this scale invariance is not mirrored in the sediment discharge at the mountain front instead downstream sediment loads reflect a complex response to both sediment supply and ambient hydraulic conditions the rivers do not transport significant amounts of sediment unless it is provided by hillslope mass wasting in the catchment removal of landslide debris is a function of the transport capacity of the stream at the site of entry thus there is a dual supply and transport control on sediment loads in bedrock floored streams over a monitoring period of 25 yr the bulk of the sediment leaving the mountain bel

holocene history of deep seated landsliding in the north fork stillaguamish river valley from surface roughness analysis radiocarbon dating and numerical landscape evolution modeling documenting spatial and temporal patterns of past landsliding is a challenging step in quantifying the effect of landslides on landscape evolution while landslide inventories can map spatial distributions lack of dateable material landslide reactivations or time access and cost constraints generally limit dating large numbers of landslides to analyze temporal patterns here we quantify the record of the holocene history of deep seated landsliding along a 25 km stretch of the north fork stillaguamish river valley washington state usa including the 2014 oso landslide which killed 43 people we estimate the ages of more than 200 deep seated landslides in glacial sediment by defining an empirical relationship between landslide deposit age from radiocarbon dating and landslide deposit surface roughness we show that roughness systematically decreases with age as a function of topographic wavelength consistent with models of disturbance driven soil transport the age roughness model predicts a peak in landslide frequency 1 000 ybp with very few landslide deposits older than 7 000 ybp or younger than 100 ybp likely reflecting a combination of preservation bias and a complex history of changing climate base level and seismic shaking in the study area most recent landslides have occurred where channels actively interact with the toes of hillslopes composed of glacial sediments suggesting that lateral channel migration is a primary control on the location of large deep seated landslides in the valley

flood driven topographic changes in a gravel cobble river over segment reach and morphological unit scales regulated rivers generally incise below dams that cut off sediment supply but how that happens and what the consequences are at different spatial scales is poorly understood modern topographic mapping at meter scale resolution now enables investigation of the details of spatial processes in this study spatial segregation was applied to a meter scale raster map of topographic change from 1999 to 2008 on the gravel cobble regulated lower yuba river in california to answer specific scientific questions about how a decadal hydrograph that included a flood peak of 22 times bankfull discharge affected the river at segment reach and morphological unit scales the results show that the river preferentially eroded sediment from floodplains compared to the channel and this not only promoted valley wide sediment evacuation but also facilitated the renewal and differentiation of morphological units especially in the channel at the reach scale area of fill and mean net rate of elevational change were directly correlated with better connectivity between the channel and floodplain while the mean rate of scour in scour areas was influenced by the ratio of slope to bankfull froude number a ratio indicative of lateral migration versus vertical downcutting hierarchical segregation of topographic change rasters proved useful for understanding multiscalar geomorphic dynamics this article is protected by copyright all rights reserved

objective landslide detection and surface morphology mapping using high resolution airborne laser altimetry a map of extant slope failures is the most basic element of any landslide assessment without an accurate inventory of slope instability it is not possible to analyze the controls on the spatial and temporal patterns of mass movement or the environmental human or geomorphic consequences of slides landslide inventory maps are tedious to compile difficult to make in vegetated terrain using conventional techniques and tend to be subjective in addition most landslide inventories simply outline landslide boundaries and do not offer information about landslide mechanics as manifested by internal deformation features in an alternative approach we constructed accurate high resolution dems from airborne laser altimetry lidar data to characterize a large landslide complex and surrounding terrain near christchurch new zealand one dimensional circular 2 d and spherical 3 d statistics are used to map the local topographic roughness in the dems over a spatial scale of 1 5 to 10 m the bedrock landslide is rougher than adjacent unfailed terrain and any of the statistics can be employed to automatically detect and map the overall slide complex furthermore statistics that include a measure of the local variability of aspect successfully delineate four kinematic units within the gently sloping lower half of the slide features with a minimum size of surface folds that have a wavelength of about 11 to 12 m and amplitude of about 1 m are readily mapped two adjacent earthflows within the landslide complex are distinguished by a contrast in median roughness and texture and continuity of roughness elements the less active of the earthflows has a surface morphology that presumably has been smoothed by surface processes the laplacian operator also accurately maps the kinematic units and the folds and longitudinal levees within and at the margins of the units finally two dimensional power spectra analyses are used to quantify how roughness varies with length scale these results indicate that no dominant length scale of roughness exists for smooth unfailed terrain in contrast zones with different styles of landslide deformation exhibit distinctive spectral peaks that correspond to the scale of deformation features such as the compression folds the topographic based analyses described here may be used to objectively delineate landslide features generate mechanical inferences about landslide behavior and evaluate relatively the recent activity of slides published by elsevier science b v

characterizing structural and lithologic controls on deep seated landsliding implications for topographic relief and landscape evolution in the oregon coast range usa in mountainous areas landslides regulate temporal variations in sediment production and may suppress simple linkages between topographic development and tectonic forcing rates and mechanisms of mass wasting depend on lithology bedrock structure and climatic and tectonic setting these factors tend to vary signifi cantly in active tectonic regions thus clouding our ability to predict how landsliding modulates topographic development over human and geological time scales here we use a novel dem based technique to document the distribution of large landslides in the oregon coast range ocr and quantify how they affect topographic relief we developed an automated algorithm that exploits the distinctive topographic signature specifi cally the relationship between curvature and gradient of large landslides to map their distribution within the gently folded tyee formation eocene deltaicsubmarine ramp sediments in contrast to steep and highly dissected terrain frequently identifi ed as characteristic of the ocr which exhibits steep planar sideslopes and highly curved low gradient ridgetops and valleys terrain prone to large landslides tends to have low values of both drainage density and curvature and gradient values that cluster between 0 16 and 0 44 the distribution of failure dominated terrain in our 10 000 km2 study area is infl uenced by systematic variations in sedimentary facies and bedrock structure the fraction of terrain altered by large landslides 0 1 km2 varies from 5 in the sand rich delta slope and proximal ramp facies southern section of our study area to 25 in the north distal ramp facies coincident with an increase in the thickness of siltstone beds and a decrease in the sandstone siltstone ratio local relief declines progressively northward suggesting that deep seated landsliding is sensitive to the thickness and frequency of low shearstrength siltstone beds and may serve to limit topographic development in the ocr structural controls are superimposed on facies related variations as deep seated landslides are frequently found on slopes whose downslope aspect corresponds to the bedrock dip direction for 1516 strike and dip measurements in our study area we calculated the fraction of proximal terrain 2 5 km altered by deep seated landsliding in the sand rich southern region the proportion of proximal slide dominated terrain increases modestly with bedrock dip in the silt rich northern region terrain altered by deep seated landsliding is pervasive and an increase in dip from 0 to 16 corresponds to a change in the fraction of slide prone terrain from 10 to 28 our technique for mapping large landslides has utility for hazard analysis and land management over million year time scales the progradational character of the tyee formation suggests that continued uplift and exhumation of the ocr should result in a southward propagation of slide prone silt rich distal facies as a result deep seated landsliding will become increasingly prominent and topographic relief in the central and southern ocr will progressively decline whereas spatial variability in climatic or tectonic forcing is often invoked to explain systematic variations in topographic development our results emphasize the importance of structural and intraformation lithologic controls on landsliding as such analyses linking surface processes climate tectonics and landscapes should be couched in the context of diverse geologic and topographic data

landslide susceptibility revealed by lidar imagery and historical records seattle washington abstract light detection and ranging lidar data were used to visually map landslides headscarps and denuded slopes in seattle washington four times more landslides were mapped than by previous efforts that used aerial photographs the mapped landforms landslides headscarps and denuded slopes were created by many individual landslides the spatial distribution of mapped landforms and 1308 historical landslides show that historical landslide activity has been concentrated on the mapped landforms and that most of the landslide activity that created the landforms was prehistoric thus the spatial densities of historical landslides on the landforms provide approximations of the landforms relative susceptibilities to future landsliding historical landslide characteristics appear to be closely related to landform type so relative susceptibilities were determined for landslides with various characteristics no strong relations were identified between stratigraphy and landslide occurrence however landslide characteristics and slope morphology appear to be related to stratigraphic conditions human activity is responsible for causing about 80 of historical seattle landslides the distribution of mapped landforms and human caused landslides suggests the probable characteristics of future human caused landslides on each of the landforms the distribution of mapped landforms and historical landslides suggests that erosion of slope toes by surface water has been a necessary condition for causing seattle landslides human activity has largely arrested this erosion which implies that landslide activity will decrease with time as hillsides naturally stabilize however evaluation of glacial age analogs of areas of recent slope toe erosion suggests that landslide activity in seattle will continue for the foreseeable future

forested landslide detection using lidar data and the random forest algorithm a case study of the three gorges china abstract the three gorges region of central western china is one of the most landslide prone regions in the world however landslide detection based on field surveys and optical remote sensing and synthetic aperture radar sar techniques remains difficult owing to the dense vegetation cover and mountain shadow in the present study an area of zigui county in the three gorges region was selected to test the feasibility of detecting landslides by employing novel features extracted from a lidar derived dtm additionally two small sites site 1 and site 2 were selected for training and were used to classify each other in addition to the aspect dtm and slope images the following feature sets were proposed to improve the accuracy of landslide detection 1 the mean aspect dtm and slope textures based on four texture directions 2 aspect dtm and slope textures based on aspect and 3 the moving average and standard deviation stdev filter of aspect dtm and slope by combining a feature selection method and the rf algorithm the classification accuracy was evaluated and landslide boundaries were determined the results can be summarized as follows 1 the feature selection method demonstrated that the proposed features provided information useful for effective landslide identification 2 feature selection achieved an improvement of about 0 44 in the overall classification accuracy with the feature set reduced by 74 from 39 to 10 this can speed up the training of the rf model 3 when fifty randomly selected 20 of landslide pixels pls and 20 of non landslide pixels pnls i e 20 of pls and pnls were utilized in addition to the selected feature subsets for training the test sets i e the remaining 80 of pls and pnls yielded an average overall classification accuracy of 78 24 the cross training and classification for site 1 and site 2 provided overall classification accuracies of 62 65 and 64 50 respectively this shows that the random sampling design which suffered some of the effects of spatial auto correlation and the proposed method in this present study contribute jointly to the classification accuracy 4 using the canny operator to delineate landslide boundaries based on the classification results of pls and pnls we obtained results consistent with the referenced landslide inventory maps thus the proposed procedure which combines lidar data a feature selection method and the rf algorithm can identify forested landslides effectively in the three gorges region

complex spatial feedbacks of tephra redistribution ice melt and surface roughness modulate ablation on tephra covered glaciers tephra fallout from the 2011 grimsvotn eruption onto svinafellsjokull iceland created an ice ash landscape of a type that is rarely studied but is nevertheless common in glaciovolcanic regions we used terrestrial laser scanning tls to measure ice surface topography and absorption at high spatial resolution confirming ablation rates either reduce or increase under thick insulating and thin reduced albedo ash deposits respectively fourier transform analysis of the tls data identified that a three fold increase in aerodynamic roughness was attributable to an increase in larger 0 2m surface features moreover tls measurements revealed the importance of ash redistribution by meltwater in generating differential melting which modifies roughness and ash patchiness such that the net effect of these spatial ash ice feedbacks was to reduce ablation rates by up to 59 the modulating effects of these previously undocumented feedbacks on ablation rates are therefore significant and must be correctly parameterized if ashcovered glacier mass balances are to be predicted correctly

spectral signatures of characteristic spatial scales and nonfractal structure in landscapes 1 landscapes are sometimes argued to be scale invariant or random surfaces yet qualitative observations suggest that they contain characteristic spatial scales we quantitatively investigate the existence of characteristic landscape scales by analyzing two dimensional fourier power spectra derived from high resolution topographic maps of two landscapes in california in both cases we find that spectral power declines sharply above a frequency that corresponds roughly to hillslope length implying that the landscape is relatively smooth at finer scales the spectra also show that both landscapes contain quasiperiodic ridge and valley structures and we derive a robust measure of the ridge valley wavelength by comparing the spectra with the statistical properties of spectra derived from randomly generated topography we show that such uniform valley spacing is unlikely to occur in a random surface we describe several potential applications of spectral analysis in geomorphology beyond the identification of characteristic spatial scales including a filtering technique that can be used to measure topographic attributes such as local relief at specific scales or in specific orientations

impact of faults on landslide in the atharamura hill along the nh 44 tripura the present study is aimed at assessing the relationship between existing faults and occurrence of landslides the geophysical techniques like geothermal imaging of fault zone soil electrical resistivity data and field verification identify the fault characteristic the present study reveals two prominent faults in the atharamura hill i e one north south extended faults and the other east west extended faults the change in the geothermal characteristic along the fault structural data dip strike and most significantly the locations of landslide close to faults provide strong correlation of the landslide and the existing faults the soil electrical resistivity data are low along the faults the subsurface resistivity profile clearly delineates the faults

deconstructing a polygenetic landscape using lidar and multi resolution analysis abstract it is difficult to deconstruct a complex polygenetic landscape into distinct process form regimes using digital elevation models dems and fundamental land surface parameters this study describes a multi resolution analysis approach for extracting geomorphological information from a lidar derived dem over a stabilized aeolian landscape in south texas that exhibits distinct process form regimes associated with different stages in landscape evolution multi resolution analysis was used to generate average altitudes using a gaussian filter with a maximum radius of 1 km at 20 m intervals resulting in 50 generated dems this multi resolution dataset was analyzed using principal components analysis pca to identify the dominant variance structure in the dataset the first 4 principal components pc account for 99 9 of the variation and classification of the variance structure reveals distinct multi scale topographic variation associated with different process form regimes and evolutionary stages our results suggest that this approach can be used to generate quantitatively rigorous morphometric maps to guide field based sedimentological and geophysical investigations which tend to use purposive sampling techniques resulting in bias and error

multiband x c l radar amplitude analysis for a mixed sand and gravel bed river in the eastern central andes abstract synthetic aperture radar sar amplitude measurements from spaceborne sensors are sensitive to surface roughness conditions near their radar wavelength these backscatter signals are often exploited to assess the roughness of plowed agricultural fields and water surfaces and less so to complex heterogeneous geological surfaces the bedload of mixed sand and gravel bed rivers can be considered a mixture of smooth compacted sand and rough gravel surfaces here we assess backscatter gradients over a large high mountain alluvial river in the eastern central andes with aerially exposed sand and gravel bedload using x band terrasar x tandem x c band sentinel 1 and l band alos 2 palsar 2 radar scenes in a first step we present theory and hypotheses regarding radar response to an alluvial channel bed we test our hypotheses by comparing backscatter responses over vegetation free endmember surfaces from inside and outside of the active channel bed area we then develop methods to extract smoothed backscatter gradients downstream along the channel using kernel density estimates in a final step the local variability of sand dominated patches is analyzed using fourier frequency analysis by fitting stretched exponential and power law regression models to the 2 d power spectrum of backscatter amplitude we find a large range in backscatter depending on the heterogeneity of contiguous smooth and rough patches of bedload material the sar amplitude signal responds primarily to the fraction of smooth sand bedload but is further modified by gravel elements the sensitivity to gravel is more apparent in longer wavelength l band radar whereas c and x band is sensitive only to sand variability because the spatial extent of smooth sand patches in our study area is typically

automated landslide mapping using spectral analysis and high resolution topographic data puget sound lowlands washington and portland hills oregon abstract landslide inventory maps are necessary for assessing landslide hazards and addressing the role slope stability plays in landscape evolution over geologic timescales however landslide inventory maps produced with traditional methods aerial photograph interpretation topographic map analysis and field inspection are often subjective and incomplete the increasing availability of high resolution topographic data acquired via airborne light detection and ranging lidar over broad swaths of terrain invites new automated landslide mapping procedures we present two methods of spectral analysis that utilize lidar derived digital elevation models of the puget sound lowlands washington and the tualatin mountains oregon to quantify and automatically map the topographic signatures of deep seated landslides power spectra produced using the two dimensional discrete fourier transform and the two dimensional continuous wavelet transform identify the characteristic spatial frequencies of deep seated landslide morphologic features such as hummocky topography scarps and displaced blocks of material spatial patterns in the amount of spectral power concentrated in these characteristic frequency bands highlight past slope instabilities and allow the delineation of landslide terrain when calibrated by comparison with detailed independently compiled landslide inventory maps our algorithms correctly classify an average of 82 of the terrain in our five study areas spectral analysis also allows the creation of dominant wavelength maps which prove useful in analyzing meter scale topographic expressions of landslide mechanics past landslide activity and landslide modifying geomorphic processes these results suggest that our automated landslide mapping methods can create accurate landslide maps and serve as effective objective and efficient tools for digital terrain analysis

machine learning based mapping of micro topographic earthquake induced paleo pulju moraines and liquefaction spreads from a digital elevation model acquired through laser scanning abstract the advent of public open source airborne laser scanning produced digital elevation models als dem has provided new perspectives on glacial geomorphology in the nordic countries seismically induced micro topographic paleo landforms can now be identified and mapped throughout the former fennoscandian ice sheet allowing spatial safety assessment for nuclear waste disposal automated machine learning techniques enable recognition of these fine scale geomorphological features efficiently and in a consistent way nationwide the current study focuses on automated recognition of paleo liquefaction spreads and pulju moraines in northern finland geomorphometric variables in different cell sizes were first derived from the 2 m als dem by gabor and principal curvature filtering to emphasize the elevational multi scale texture of these paleo seismic landforms the gabor textural variables were considered as a baseline method and the principal curvature features including maximum and minimum curvature were used because they have previously been proven critical in recognition of concave and convex elongated features both sets of raster variables were then turned into histogram based features and input into a non linear supervised multilayer perceptron early stop committee which is a neural network classifier the leave one out cross validation performance results indicated principal curvature features to be highly successful with 94 accuracy principal curvatures provided a clear improvement to gabor based features which provided significantly lower accuracies between 83 and 85 the study demonstrates the high success of supervised neural network based classification of als dem data and derived textural features capturing the multi scale nature of the micro topographic liquefaction spreads and pulju moraines the approach could be utilized for time efficient mapping of these paleo seismic geomorphologies to complete paleo seismic databases in formerly glaciated regions

runoff generation processes estimated from hydrological observations on a steep forested hillslope with a thin soil layer abstract in order to understand runoff generation processes on a forested hillslope involving large heterogeneities this study monitored runoff from a steep hillslope with a thin soil layer as well as matric potential within it and analyzed their responses to storm rainfall a comparison of storm runoff responses from the study slope with those from two adjacent catchments one of which includes it showed that physical properties of the slope reflected the runoff characteristics although no responses occurred in very dry conditions because of the absence of wet zones near the stream the area contributing to storm runoff more rapidly extended to the whole slope due to its topographic properties they also caused its steep hydrographs produced in the wettest condition where almost all the rainfall contributed to storm runoff in this wettest condition tensiometric responses near bedrock showed the vertical quick propagation of the rainfall pulse and a good agreement of storm hydrograph simulated through a kinematic wave runoff model suggested that runoff from the slope was produced by a lateral flow on the bedrock receiving the quick propagation in a transition process from dry to the wettest conditions the development of the lateral flow producing smaller responses at the downslope end was estimated from decreasing of matric potential near bedrock from high negative to low values with increasing cumulative rainfall

estimating aerodynamic roughness over complex surface terrain 1 surface roughness plays a key role in determining aerodynamic roughness length zo and shear velocity both of which are fundamental for determining wind erosion threshold and potential while zo can be quantified from wind measurements large proportions of wind erosion prone surfaces remain too remote for this to be a viable approach alternative approaches therefore seek to relate zo to morphological roughness metrics however dust emitting landscapes typically consist of complex small scale surface roughness patterns and few metrics exist for these surfaces which can be used to predictzofor modeling wind erosion potential in this study terrestrial laser scanning was used to characterize the roughness of typical dust emitting surfaces playa and sandar where element protrusion heights ranged from 1 to 199mm over which vertical wind velocity profiles were collected to enable estimation of zo our data suggest that although a reasonable relationship r 2 0 79 is apparent between 3 d roughness density and zo the spacing of morphological elements is far less powerful in explaining variations in zo than metrics based on surface roughness height r 2 0 92 this finding is in juxtaposition to wind erosion models that assume the spacing of larger scale isolated roughness elements is most important in determining zo rather our data show that any metric based on element protrusion height has a higher likelihood of successfully predicting zo this finding has important implications for the development of wind erosion and dust emission models that seek to predict the efficiency of aeolian processes in remote terrestrial and planetary environments

detailed mapping of shallow landslides in eastern oklahoma and western arkansas and potential triggering by oklahoma earthquakes abstract landslides have long been considered one of the main erosive drivers that sculpt hillslopes over time tectonic forces raise slopes that can be sculpted by climate and the degree to which they can be sculpted depends upon the underlying lithology and hillslope geomorphology landslides destroy life and property and contribute to the evolution of mountain landscapes by generating and transporting hillslope sediments in this study we investigate the dynamics of soil mantled hillslopes in eastern oklahoma and western arkansas usa by mapping shallow landslides evaluating the frequency and magnitude of the landslides and quantifying the surface geometries we mapped 185 shallow landslides in a 150 km2 area the approximate ages of landslides and the frequencies and magnitudes area volume and runout were estimated using historical aerial photographs the landslide database was then used to compute rate of landslide occurrence and sediment yield in addition landslide surface geometries including slope curvature and surface roughness were determined from 10 m ned and 2 m lidar elevation data the hillslope susceptibility studies derived from elevation data were augmented by our review of common historical accounts that link landslides in the study region to the 1952 m 5 4 el reno oklahoma earthquake 300 km away in light of that case study we determined the frequency of historical earthquakes that impart 2 kpa dynamic stresses for the study area since 1900 and find an increased potential for dynamic stress perturbation of landslide activity since 2010 all these characteristics were then evaluated to understand the dynamics of hillslopes and hillslope susceptibility to shallow landslides frequency assessment of mapped landslides suggested that frequency of landslides increased significantly during 2005 2016 compared to 1995 2005 on average 10 shallow landslides occurred every year during 2005 2016 these landslides alone contributed 1 5 105 m3 yr sediment yield rate 0 10 cm yr of sediments surface roughness values were relatively higher in landslide areas compared to that of surrounding non landslide areas the surface roughness index mapped 84 of observed landslides and suggests that the index could be used to map hillslope susceptibility to landslides for future planned studies

object oriented identification of forested landslides with derivatives of single pulse lidar data in contrast to the many studies that use expert based analysis of lidar derivatives for landslide mapping in forested terrain only few studies have attempted to develop semi automatic methods for extracting landslides from lidar derivatives while all these studies are pixel based it has not yet been tested whether object oriented analysis ooa could be an alternative this study investigates the potential of ooa using only single pulse lidar derivatives such as slope gradient roughness and curvature to map landslides more specifically the focus is on both lidar data segmentation and classification of slow moving landslides in densely vegetated areas where spectral data do not allow accurate landslide identification a multistage procedure has been developed and tested in the flemish ardennes belgium the procedure consists of 1 image binarization and multiresolution segmentation 2 classification of landslide parts main scarps and landslide body segments and non landslide features i e earth banks and cropland fields with supervised support vector machines at the appropriate scale 3 delineation of landslide flanks 4 growing of a landslide body starting from its main scarp and 5 final cleaning of the inventory map the results obtained show that ooa using lidar derivatives allows recognition and characterization of profound morphologic properties of forested deep seated landslides on soil covered hillslopes because more than 90 of the main scarps and 70 of the landslide bodies of an expert based inventory were accurately identified with ooa for mountainous areas with bedrock on the other hand creation of a transferable model is expected to be more difficult

wavelet analyses of mars polar topography we have analyzed topography tracks over the mars northern polar cap composed of h2o ice co2 ice and sediments and the antarctic ice sheet on earth using a mexican hat wavelet transform the great utility of the wavelet transform is that it gives both spatial and spectral resolution we have used the variance of the wavelet output in order to quantify the spectral content of the topography tracks at short wavelengths for both the mars northern polar cap and the antarctic ice sheet we find a power law dependence of the wavelet transform variance on wavelength with a power law exponent of 3 5 3 7 this compares with a power law exponent of 2 0 brownian motion typical of topography on both mars and earth there is a power law smoothing of the ice topography at short wavelengths on both planetary bodies at long wavelengths we infer a similar power law dependence with 1 5 2 0 typical of planetary topography a transition is observed between the smooth short wavelength behavior high to rougher long wavelength behavior low this fairly sharp transition occurs at a wavelength of 24 km for mars and 11 km for antarctica the transitions appear to scale with ice thicknesses and suggest a relaxation of short wavelength topography by ice flows or surface processes

the topographic signature of a major typhoon in august 2009 the typhoon morakot characterized by a cumulative rainfall up to 2884 mm in about three days triggered thousands of landslides in taiwan the availability of lidar surveys before 2005 and after 2010 this event offers a unique opportunity to investigate the topographic signatures of a major typhoon the analysis considers the comparison of slope area relationships derived by lidar digital terrain models dtms this approach has been successfully used to distinguish hillslope from channelized processes as a basis to develop landscape evolution models and theories and understand the linkages between landscape morphology and tectonics climate and geology we considered six catchments affected by a different degree of erosion three affected by shallow and deep seated landslides and three not affected by erosion for each of these catchments 2 m dtms were derived from lidar data the scaling regimes of local slope versus drainage area suggested that for the catchments affected by landslides i the hillslope to valley transitions morphology for a given value of drainage area is shifted towards higher value of slopes thus indicating a likely migration of the channelized processes and erosion toward the catchment boundary the catchment head becomes steeper because of erosion ii the topographic gradient along valley profiles tends to decrease progressively the valley profile becomes gentler because of sediment deposition after the typhoon the catchments without any landslides present a statistically indistinguishable slope area scaling regime these results are interesting since for the first time using multi temporal high resolution topography derived by lidar we demonstrated that a single climate event is able to cause significant major geomorphic changes on the landscape detectable using slope area scaling analysis this provides new insights about landscape evolution under major climate forcing copyright 2015 john wiley sons ltd

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

wavelet analysis for geophysical applications wavelet transforms originated in geophysics in the early 1980s for the analysis of seismic signals since then significant mathematical advances in wavelet theory have enabled a suite of applications in diverse fields in geophysics the power of wavelets for analysis of nonstationary processes that contain multiscale features detection of singularities analysis of transient phenom ena fractal and multifractal processes and signal com pression is now being exploited for the study of several processes including space time precipitation remotely sensed hydrologic fluxes atmospheric turbulence can opy cover land surface topography seafloor bathymetry and ocean wind waves it is anticipated that in the near future significant further advances in understanding and modeling geophysical processes will result from the use of wavelet analysis in this paper we review the basic properties of wavelets that make them such an attractive and powerful tool for geophysical applications we dis cuss continuous discrete orthogonal wavelets and wavelet packets and present applications to geophysical processes

kinematics of active earthflows revealed by digital image correlation and dem subtraction techniques applied to multi temporal lidar data earthflow type landslides are persistent natural hazards having deep socio economic and environmental consequences they have significantly contributed to the geomorphic evolution of mountainous slopes in europe since the late glacial an understanding of their complex kinematics is crucial to better constrain the processes governing their occurrence and mobility in this work we explored the possibility to quantify displacement vectors on a spatially distributed basis and to quantify volumetric transfer at the slope scale with regard to a large flow type landslide located in the northern apennines of italy for this purpose we applied digital image correlation dic and digital elevation model differencing demod techniques to multi temporal airborne lidar surveys of 2006 2007 and 2009 the dic was applied to greyscale slope gradient maps retrieved after precise co registration of lidar surveys thereby movement patterns over various sectors of the landslide were reconstructed and quantified most notably up to 20 m in the head zone up to 51 m in the lower main track and up to about 27 m at the landslide toe the demod analysis revealed significant mass transfer from the source to the tracks and toe zone with the upper flow tracks acting as temporal storage of large amounts of material the mass balance indicated that significant amounts of advancing landslide debris were eroded by a local stream an integrated analysis of demod and dic results allowed for a discussion of governing processes such as the transition from slide to flow the influence of underlying topography on earthflow mobility and the role of undrained loading as a mechanism of toe zone reactivation in conclusion the successful application of dic and demod to the case study underlines the added value of high resolution dems in the analysis of earthflow kinematics toward a better understanding of their role in the geomorphic evolution of slopes copyright 2012 john wiley sons ltd

application of a multi temporal lidar derived digital terrain model in a landslide volume estimation sediments produced by landslides are crucial in the sediment yield of a catchment debris flow forecasting and related hazard assessment on a regional scale however it is difficult and time consuming to measure the volumes of such sediment this paper uses a lidar derived digital terrain model dtm taken in 2005 and 2010 at 2 m resolution to accurately obtain landslide induced sediment volumes that resulted from a single catastrophic typhoon event in a heavily forested mountainous area of taiwan the landslides induced by typhoon morakot are mapped by comparison of 25 cm resolution aerial photographs taken before and after the typhoon in an 83 6 km2 study area each landslide volume is calculated by subtraction of the 2005 dtm from the 2010 dtm and the scaling relationship between landslide area and its volume are further regressed the relationship between volume and area are also determined for all the disturbed areas vl 0 452al1 242 and for the crown areas of the landslides vl 2 510al1 206 the uncertainty in estimated volume caused by use of the lidar dtms is discussed and the error in absolute volume estimation for landslides with an area 105 m2 is within 20 the volume area relationship obtained in this study is also validated in 11 small to medium sized catchments located outside the study area and there is good agreement between the calculation from dtms and the regression formula by comparison of debris volumes estimated in this study with previous work it is found that a wider volume variation exists that is directly proportional to the landslide area especially under a higher scaling exponent copyright 2013 john wiley sons ltd

surface texture analysis of a high resolution dtm interpreting an alpine basin abstract this study focuses on a geomorphometric analysis of a small headwater basin of the dolomites eastern italian alps the analysis of the fine scale surface morphology was performed on a high resolution digital elevation model cell size 2 m derived from an airborne lidar survey the topography was synthesized by a set of spatial statistical indexes representing a signature of the local surface morphology and the relationships between the geomorphometric indexes and morphological features were evaluated the studied basin was then segmented by means of a fuzzy k means classification algorithm into different spatial subdomains characterized by specific local geomorphic signatures this method allows us to objectively choose the optimal combination of the number of classes and degree of fuzziness characterizing the studied basin accordingly the analysis can be adopted to the characteristics of the studied area improving the interpretation of surface morphology and offering a valuable tool for comparative analysis between different geomorphological contexts the results of the classification were compared with the actual surface morphology based on high resolution orthophotos aerial photos and field surveys

channel network extraction from high resolution topography using wavelets 1 the availability of high resolution topography from lidar offers new opportunities for objectively extracting the channels directly from a dem using local topographic information instead of inferring them indirectly based on global criteria such as area or area slope threshold relationships here we introduce the use of wavelet filtering to delineate threshold curvatures for defining valleys and threshold slope direction change for defining probable channeled portions of the valleys this approach exploits the topographic signatures uniquely found in high resolution topography and reveals the fuzzy topographic transition in which local weakly convergent areas lie at the transition between hillslopes and valleys

measuring multiresolution surface roughness using v system surface roughness is a land surface parameter that is widely used in terrain analysis some typical roughness details which have important effects on surface analysis fail to be characterized on previous roughness maps the objective of this paper is to provide a more accurate small to large scale roughness overview the new roughness method is designed based on a complete orthogonal system called the v system the v system roughness utilizes the special functions to detect and extract the roughness characteristics from high resolution digital elevation models dems in this paper lunar orbiter laser altimeter derived dems are used as the source data for the roughness calculation compared with the global root mean square slope and fourier based roughness maps the v system roughness maps show that more typical roughness details have been added to clearly indicate the small roughness variations on the large map furthermore the reliability and practicability of v system roughness are demonstrated based on the multiresolution dems as an example the statistical parameters of the roughness characteristics in the lunar maria and highlands identify the fact that the highlands are rougher at all scales than the maria and this difference corresponds to the basic roughness property

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

application of wavelet analysis to the study of spatial pattern of morphotectonic lineaments in digital terrain models a case study tectonic faults are often associated with characteristic geomorphological features such as linear valleys ridgelines and slope breaks that can be identified as lineaments in remotely sensed images or digital terrain models lineaments of tectonic origin are often characterised by periodicity and characteristic spatial pattern unlike traditional methods of autocorrelation variogram lineament density and fourier analysis wavelet analysis is capable of capturing and describing both periodicity and spatial pattern of lineaments in this paper a case study is shown for the application of wavelet analysis to morphotectonic lineament investigation results of wavelet analysis are compared to traditional methods although this study involves dem derived morphological lineaments the presented wavelet analysis can be also used for lineaments derived from remotely sensed images these results hold for this case study and provide a good assessment of the relative abilities of wavelet analysis but it remains to be seen how effective it is for other data sources areas and geological terrain

repeated fluid expulsion through sub seabed chimneys offshore norway in response to glacial cycles abstract focused fluid flow through sub seabed sediments is a common phenomenon on continental margins worldwide however the governing controls and timing of this fluid release have been difficult to understand in particular for fluid flow features buried beneath sub surface sediments a link between fluid flow activity ensuing pockmark formation and the last glacial maximum has been hypothesized on the formerly glaciated norwegian margin new high resolution p cable 3d seismic data from the nyegga area on the mid norwegian margin reveal at least two more periods of fluid expulsion from sub seabed sediments the 3d seismic data show depositional patterns within chimney features expressed as truncations of seismic horizons against the flanks of the chimneys the truncations are interpreted by analogy with present day observations as evidence for buried carbonate mounds and or sediment wash out during formation of pockmarks in the past the truncations are hence an indicator and a chronological marker for fluid expulsion in the past the classification of chimneys results in three major groups 1 chimneys that have been formed and consecutively reactivated one or two times during the last 200 kyr and that have a fluid flow expression at the present seafloor 2 chimneys that are approx 125 160 ka bp old without any associated fluid flow expression at the present day seafloor 3 chimneys with no stratigraphical evidence for reactivation formed after the last glacial maximum 18 25 ka bp the observations suggest that each activity period was likely related to the last stages of maximum glaciations in the region the emplacement of thick sequences of glacigenic debris flow deposits during these maximum stages most likely caused rapid increase in overpressure and subsequently the formation of focused fluid flow features piercing through sediments of the naust formation at nyegga

sediment yield spatial characteristics and the long term evolution of active earthflows determined from airborne lidar and historical aerial photographs eel river california in mountainous landscapes with weak fine grained rocks earthflows can dominate erosion and landscape evolution by supplying sediment to channels and controlling hillslope morphology to estimate the contribution of earthflows to regional sediment budgets and identify patterns of landslide activity earthflow movement needs to be quantified over significant spatial and temporal scales presently there is a paucity of data that can be used to predict earthflow behavior beyond the seasonal scale or over spatially extensive study areas across 226 km 2 of rapidly eroding franciscan complex rocks of the eel river catchment northern california we used a combination of lidar light detection and ranging and orthorectified historical aerial photographs to objectively map earthflow movement between 1944 and 2006 by tracking the displacement of trees growing on earthflow surfaces we find that 7 3 of the study area experienced movement over this 62 yr interval preferentially in sheared argillaceous lithology this movement is distributed across 122 earthflow features that have intricate elongate planform shapes a preferred south southwesterly aspect and a mean longitudinal slope of 31 the distribution of mapped earthflow areas is well approximated by a lognormal distribution with a median size of 36 500 m 2 approximately 6 of the study area is composed of earthflows that connect to major channels these flows generated an average sediment yield of 19 000 t km 2 yr 1 rock erosion rate of 7 6 mm yr over the 62 yr study period equating to a regional yield of 1100 t km 2 yr 1 0 45 mm yr if distributed across the study area as such a small fraction of the landscape can account for half of the regional denudation rate estimated from suspended sediment records 2200 t km 2 yr 1 or 0 9 mm yr we propose a conceptual model for long term earthflow evolution wherein earthflows experience intermittent activity and long periods of dormancy when limited by the availability of readily mobilized sediment on upper slopes ultimately high order river channels and ephemeral gully networks may serve to destabilize hillslopes controlling the evolution of earthflow prone terrain

high resolution topography for understanding earth surface processes opportunities and challenges abstract in the last decade a range of new remote sensing techniques has led to a dramatic increase in terrain information providing new opportunities for a better understanding of earth surface processes based on geomorphic signatures technologies such as airborne and terrestrial lidar light detection and ranging to obtain high resolution topography have opened avenues for the analysis of landslides hillslope and channellization processes river morphology active tectonics volcanic landforms and anthropogenic signatures on topography this review provides an overview of the recent flourishing literature on high resolution topographic analyses underlining their opportunities and critical issues such as their limitations the goal is to provide answers to questions such as what kind of processes can be analyzed through high resolution topographic data and how to do it the review focuses on two different environments natural and engineered landscapes in both contexts high resolution topography offers opportunities to better understand geomorphic processes from topographic signatures particular attention is given to engineered landscapes in which the direct anthropic alteration of processes is significant the last part of the review discusses future challenges

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

the effectiveness of hillshade maps and expert knowledge in mapping old deep seated landslides large deep seated landslides with a shear surface deeper than 3 m and a mean affected area of 4 2 ha are common features in the flemish ardennes none of these deep seated landslides are dated but they are assumed to be rather old 100 years because most of these landslides are located under forest aerial photo interpretation commonly used for the creation of landslide inventories is not a suitable tool to map the landslides in the flemish ardennes therefore an intensive 100 day field survey was carried out by two geomorphologists in a 430 km 2 study area this resulted in a landslide inventory map indicating the location of 135 large deep seated landslides but field surveys are time consuming and thus very expensive therefore a cheaper and faster mapping technique was tested a hillshade map was constructed for the study area in a gis idris132 from a 5 m resolution digital elevation model dem seven experts were given 1 h to indicate all the hillslope sections which they suspected to be possible landslides on a copy of the aforementioned map scale 1 100 000 in total this exercise took only 1 day i e 7 person hours large differences in the number of presumed landslides and the extent of the hillslopes thought to be affected by landslides were reported among the seven experts the polygon and pixel efficiency were introduced to estimate the quality of the landslide maps based on hillshade maps and expert knowledge compared to the field survey based landslide inventory the quality of the landslide inventories based on the hillshade maps and expert knowledge was relatively low experts familiar with the study area obtained somewhat better results than experts who visited the study area only once a combination of the seven expert maps did not result in a good inventory map because too many unaffected hillslopes were incorrectly indicated as affected by landslides the results obtained in this study are comparable to an investigation carried out by wills c j mccrink t p 2002 comparing landslide inventories the map depends on the method environmental and engineering geoscience 8 279 293 although the tested method can never replace a detailed field survey taking into account the proposed improvements it can be used for the creation of a regional inventory map of old landslides in a densely forested area where light detection and ranging lidar data are unavailable c 2004 elsevier b v all rights reserved

landslides earthquakes and erosion this paper relates landslide inventories to erosion rates and provides quantitative estimates of the landslide hazard associated with earthquakes we do this by utilizing a three parameter inverse gamma distribution which fits the frequency area statistics of three substantially dcompletet landslide event inventories a consequence of this general distribution is that a landslide event magnitude ml lognlt can be introduced where nlt is the total number of landslides associated with the landslide event using this general distribution landslide event magnitudes ml can be obtained from incomplete landslide inventories and the total area and volume of associated landslides as well as the area and volume of the maximum landslides can be directly related to the landslide event magnitude using estimated recurrence intervals for three landslide events and the time span for two historical inventories we estimate regional erosion rates associated with landslides as typically 0 1 2 5 mm year 1 we next give an empirical correlation between the earthquake magnitude associated landslideevent magnitude and the total volume of associated landslides using these correlations we estimate that the minimum earthquake magnitudes that will generate landslides is m 4 3f0 4 finally using gutenberg richter frequency magnitude statistics for regional seismicity we relate the intensity of seismicity in an area and the magnitude of the largest regional earthquakes to erosion rates we find that typical seismically induced erosion rates in active subduction zones are 0 2 7 mm year 1 and adjacent to plate boundary strike slip fault zones are 0 01 0 7 mm year 1

sediment flux from a mountain belt derived by landslide mapping in humid uplands landsliding is the dominant mass wasting process in the western southern alps of new zealand landslides are scale invariant and have a power law magnitude frequency distribution independent studies from other regions suggest that this is a general property of landsliding this observation is of critical importance to the evaluation of the impact of events of different length scales over different time intervals on landscape evolution it is particularly useful when estimating regional geomorphic rates because it constrains the frequency and overall significance of extreme events which cannot otherwise be evaluated by integrating the complete response of the system we estimate the regional denudation rate due to landsliding to be 9 4 mm yr 1 sediment discharge from the western southern alps is dominated by landslide derived material

developing an algorithm for automated geometric analysis and classification of landslides incorporating lidar derived dem amending landslides inventories is immensely important to policy and decision makers alike sliding creates geometric shapes on the earth s surface this study presents the utilization of lidar high resolution digital elevation model dem in the alborz mountains iran to refurbish the existing landslide inventory dataset by implementing the proposed algorithm the method consists of the automated derivation of landslide geometry length width and area followed by classification of landslide types considering length width and flow direction this study has used the trapezoidal rule for numerical integration to develop the proposed algorithm the landslides were then classified into four types very long long very wide and wide based on slope length and width this geometric classification of landslides is based on the geographical coordinates slope angle length l and width w and further failure flow direction a total of 95 landslides were updated from the existing inventory database the proposed method was verified and evaluated by field observations and 14 samples were tested to determine the relative error the results demonstrated that the mean percentage relative error is 0 496 in length and width and 0 008 in area related to the gis analysis the accuracy performance of determining the landslide s type is 92 the purposefulness of this algorithm is to increase the accuracy performance of landslides geometry analysis and automated measurements associated with the usual gis platforms such as arcgis

mapping gullies dunes lava fields and landslides via surface roughness abstract gully erosion is a widespread and significant process involved in soil and land degradation mapping gullies helps to quantify past and anticipate future soil losses digital terrain models offer promising data for automatically detecting and mapping gullies especially in vegetated areas although methods vary widely measures of local terrain roughness are the most varied and debated among these methods rarely do studies test the performance of roughness metrics for mapping gullies limiting their applicability to small training areas to this end we systematically explored how local terrain roughness derived from high resolution light detection and ranging lidar data can aid in the unsupervised detection of gullies over a large area we also tested expanding this method for other landforms diagnostic of similarly abrupt land surface changes including lava fields dunes and landslides as well as investigating the influence of different roughness thresholds resolutions of kernels and input data resolution and comparing our method with previously published roughness algorithms our results show that total curvature is a suitable metric for recognising analysed gullies and lava fields from lidar data with comparable success to that of more sophisticated roughness metrics tested dunes or landslides remain difficult to distinguish from the surrounding landscape partly because they are not easily defined in terms of their topographic signature

critiques of the seismic hypothesis and the vegetation stabilization hypothesis for the formation of mima mounds along the western coast of the u s abstract a recent paper published in geomorphology by gabet et al 2014 presents the results of a numerical model supporting the hypothesis that burrowing mammals build mima mounds small densely packed hillocks found primarily in the western united states the model is based on field observations and produces realistic looking mounds with spatial distributions similar to real moundfields alternative explanations have been proposed for these mima mounds including formation by seismic shaking and vegetation controlled erosion and deposition in this short communication we present observations from moundfields in the coastal states of the western u s that are incompatible with these alternative theories

generating landslide inventory by participatory mapping an example in purwosari area yogyakarta java abstract this paper proposes an approach for landslide inventory mapping considering actual conditions in indonesia no satisfactory landslide database exists what exists is inadequate focusing on data response rather than on pre disaster preparedness and planning the humid tropical climate also leads a rapid vegetation growth so past landslides signatures are covered by vegetation or dismantled by erosion process generating landslide inventory using standard techniques still seems difficult a catalog of disasters from local government village level was used as a basis of participatory landslide inventory mapping eyewitnesses or landslide disaster victims were asked to participate in the reconstruction of past landslides field investigation focusing on active participation from communities with the use of an innovative technology was used to verify the landslide events recorded in the disaster catalog statistical analysis was also used to obtain the necessary relationships between geometric measurements including the height of the slope and length of run out area and volume of displaced materials the probability distributions of landslide area and volume and mobilization rate the result shows that run out distance is proportional to the height of the slope the frequency distribution calculated by using non cumulative distribution empirically exhibits a power law fractal statistic even though rollover can also be found in the dataset this cannot be the result of the censoring effect or incompleteness of the data because the landslide inventory dataset can be classified as having complete data or nearly complete data the so called participatory landslide inventory mapping method is expected to solve the difficulties of landslide inventory mapping and can be applied to support pre disaster planning and preparedness action to reduce the landslide disaster risk in indonesia it may also supplement the usually incomplete data in a typical landslide inventory

use of lidar derived images for mapping old landslides under forest large deep seated landslides are common features in the flemish ardennes belgium as most of these old 100 years landslides are located under forest in this hilly region aerial photograph interpretation is not an appropriate landslide mapping method this study tested the potential of lidar light detection and ranging images for mapping old landslides under forest landslide inventory maps were created for a 125 km2 area by applying the expert knowledge of seven geomorphologists to lidar derived hillshade slope and contour line maps in a gis environment each of the seven lidar based landslide inventories was compared i with the other six ii with a detailed field survey based inventory and iii with a comparable study in which topographic data were extracted from a topographical map the combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies expressed in terms of positional mismatch were used to evaluate the quality of the lidar based inventory maps high quality lidar derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey and have positional discrepancies smaller than 70 per cent when compared with the field survey based inventory map four experts and the combination map of all experts satisfied these criteria together the seven experts indicated all landslides mapped in the field importantly lidar enabled the experts to find ten new landslides and to correct the boundaries of eleven of the 77 landslides mapped during the field survey hence this study showed that large scale lidar derived maps analysed by experienced geomorphologists can significantly improve field survey based inventories of landslides with a subdued morphology in hilly regions copyright 2006 john wiley sons ltd

comparing landslide inventory maps landslide inventory maps are effective and easily understandable products for both experts such as geomorphologists and for non experts including decision makers planners and civil defense managers landslide inventories are essential to understand the evolution of landscapes and to ascertain landslide susceptibility and hazard despite landslide maps being compiled every year in the word at different scales limited efforts are made to critically compare landslide maps prepared using different techniques or by different investigators based on the experience gained in 20 years of landslide mapping in italy and on the limited literature on landslide inventory assessment we propose a general framework for the quantitative comparison of landslide inventory maps to test the proposed framework we exploit three inventory maps the first map is a reconnaissance landslide inventory prepared for the umbria region in central italy the second map is a detailed geomorphological landslide map also prepared for the umbria region the third map is a multi temporal landslide inventory compiled for the collazzone area in central umbria results of the experiment allow for establishing how well the individual inventories describe the location type and abundance of landslides to what extent the landslide maps can be used to determine the frequency area statistics of the slope failures and the significance of the inventory maps as predictors of landslide susceptibility we further use the results obtained in the collazzone area to estimate the quality and completeness of the two regional landslide inventory maps and to outline general advantages and limitations of the techniques used to complete the inventories

extraction of multi scale landslide morphological features based on local g i using airborne lidar derived dem abstract for automatic landslide detection landslide morphological features should be quantitatively expressed and extracted high resolution digital elevation models dems derived from airborne light detection and ranging lidar data allow fine scale morphological features to be extracted but noise in dems influences morphological feature extraction and the multi scale nature of landslide features should be considered this paper proposes a method to extract landslide morphological features characterized by homogeneous spatial patterns both profile and tangential curvature are utilized to quantify land surface morphology and a local gi statistic is calculated for each cell to identify significant patterns of clustering of similar morphometric values the method was tested on both synthetic surfaces simulating natural terrain and airborne lidar data acquired over an area dominated by shallow debris slides and flows the test results of the synthetic data indicate that the concave and convex morphologies of the simulated terrain features at different scales and distinctness could be recognized using the proposed method even when random noise was added to the synthetic data in the test area cells with large local gi values were extracted at a specified significance level from the profile and the tangential curvature image generated from the lidar derived 1 m dem the morphologies of landslide main scarps source areas and trails were clearly indicated and the morphological features were represented by clusters of extracted cells a comparison with the morphological feature extraction method based on curvature thresholds proved the proposed method s robustness to dem noise when verified against a landslide inventory the morphological features of almost all recent 10 years landslides were extracted this finding indicates that the proposed method can facilitate landslide detection although the cell clusters extracted from curvature images should be filtered using a filtering strategy based on supplementary information provided by expert knowledge or other data sources

morphology and internal structure of a dormant landslide in a hilly area the collinabos landslide belgium abstract this study attempts to reconstruct the history of the collinabos landslide a landslide with a fresh morphology that is representative for more than 150 dormant deep seated 3 m landslides in the flemish ardennes belgium a geomorphological map was created based on lidar light detection and ranging derived maps and detailed field surveys the map showed that the landslide consisted of three zones with significant differences in surface topography the northern landslide zone 1 is characterised by at least five reverse slopes whereas zones 2 and 3 the southern landslide zones have only two reverse slopes and a convex foot electric resistivity profiles measured in zones 1 and 2 revealed that the differences in surface topography were not related to differences in internal structure as both parts of the landslide were initiated as a rotational earth slide with a surface of rupture at 15 m deep where the displaced material broke apart in two blocks however two shear surfaces of reactivations within landslide debris were only distinguished in the accumulation area of zone 1 the observed differences in surface morphology can be caused by a temporary conversion of a forest into cropland in zone 2 it is suggested that reverse slopes of smaller reactivations within landslide debris were obliterated during the agricultural activities ams radiocarbon dating of organic material found in ponds located in reverse slopes generally resulted in relatively recent dates i e 1400 1950 cal ad suggesting that several of the small local reactivations occurred in that period one dating at 8700 8440 cal bp of organic matter collected in a reverse slope in zone 1 suggests that an initiation under periglacial conditions cannot be excluded for the collinabos landslide by combining different technologies this study provides valuable information for a better understanding of dormant landslides

mapping quaternary alluvial fans in the southwestern united states based on multiparameter surface roughness of lidar topographic data 1 quaternary alluvial fans have diverse surface morphologies related to both depositional and weathering processes numerous studies have demonstrated that the surface expression and morphometry of alluvial fans can be used as an indicator of their relative age of deposition but only recently has there been an effort to utilize high resolution topographic data to differentiate alluvial fans by surface age with automated and quantifiable routines we developed a quantitative model for mapping the relative age of alluvial fan surfaces based on multiparameter surface roughness values computed from 1 m resolution lidar topographic data roughness is defined as a function of observational scale and integration of slope curvature and aspect topographic parameters alluvial fan roughness values were computed across multiple observation scales 3 3 m to 150 150 m based on the standard deviation sd of slope curvature tangential and aspect topographic parameters plots of roughness value versus size of observation scale suggest that the sd of each parameter over a 7 7 m observation window best identified the signature of surface roughness elements roughness maps derived from slope curvature and aspect at this scale were integrated using fuzzy logic the integrated roughness map was then classified into five relative morphostratigraphic surface age categories active wash to 400 ka and statistically compared with a similar fivefold surface age map of alluvial fans developed using traditional field surveys and aerial photographic interpretation the model correctly predicted the distribution and relative surface age of 61 of alluvial fan landforms based on traditional mapping techniques

combining geomorphometry feature extraction techniques and earth surface processes research the way forward abstract in recent years the wealth of technological development revolutionised our ability to collect data in geosciences due to the unprecedented level of detail of these datasets geomorphologists are facing new challenges giving more in depth answers to a broad er range of fundamental questions across the full spectrum of the earth s and planetary processes this contribution builds on the existing literature of geomorphometry the science of quantitative land surface analysis and feature extraction translate land surface parameters into extents of geomorphological elements it provides evidence of critical themes as well as emerging fields of future research in the digital realm supporting the likely effectiveness of geomorphometry and feature extractions as they are advancing the theoretical empirical and applied dimension of geomorphology the review further discusses the role of geomorphometric legacies and scientific reproducibility and how they can be implemented in the hope that this will facilitate action towards improving the transparency and efficiency of scientific research and accelerate discoveries in geomorphology in the current landscape substantial changes in landforms ecosystems land use hydrological routing and direct anthropogenic modifications impact systems across the full spectrum of geomorphological processes although uncertainties in the precise nature and likelihood of changes exist geomorphometry and feature extraction can aid exploring process regimes and landscape responses taken together they can revolutionise geomorphology by opening the doors to improved investigations crossing space and time scales blurring the boundaries between traditional approaches and computer modelling and facilitating cross disciplinary research ultimately the exploitation of the available wealth of digital information can help to translate our understanding of geomorphic processes which is often based on observations of past or current conditions into the rapidly changing future

producing a landslide inventory map using pixel based and object oriented approaches optimized by taguchi method abstract landslides are considered one of the most important natural hazards mapping landslides and producing landslide inventory maps have received special attention from a wide range of specialists the main objective of this study was to produce landslide inventory maps using advanced pixel based ann and svm and object oriented approaches the most important challenge in this case is to determine the optimum structure of classification methods the taguchi method was to perform optimization of the structure of ann and svm and segmentation process in the object oriented classification method results showed that the taguchi method can be effectively used to cope with this problem it significantly reduces the number of classification tests we also showed that there were no significant differences existed between ann and svm approaches 2 value of 3 33 however we demonstrated that object oriented approaches significantly outperformed the pixel based classification methods z value of 5 70 in producing a landslide inventory map the accurate map produced using an object oriented approach overall accuracy of 0 90 effectively determines the shape of landslides and also efficiently shows the intensifying effects of land use changes in the occurrence of landslides

analysis of lidar derived topographic information for characterizing and differentiating landslide morphology and activity abstract this study used airborne laser altimetry lidar to examine the surface morphology of two canyon rim landslides in southern idaho the high resolution topographic data were used to calculate surface roughness slope semivariance and fractal dimension these data were combined with historical movement data global positioning systems gps and laser theodolite and field observations for the currently active landslide and the results suggest that topographic elements are related to the material types and the type of local motion of the landslide weak unconsolidated materials comprising the toe of the slide which were heavily fractured and locally thrust upward had relatively high surface roughness high fractal dimension and high vertical and lateral movement the body of the slide which predominantly moved laterally and consists mainly of undisturbed older canyon floor materials had relatively lower surface roughness than the toe the upper block consisting of a down dropped section of the canyon rim that has remained largely intact had a low surface roughness on its upper surface and high surface roughness along fractures and on its west face unrelated to landslide motion the upper block also had a higher semivariance than the toe and body the topographic data for a neighboring older and larger landslide complex which failed in 1937 are similarly used to understand surface morphology as well as to compare to the morphology of the active landslide and to understand scale dependent processes the morphometric analyses demonstrate that the active landslide has a similar failure mechanism and is topographically more variable than the 1937 landslide especially at scales 20 m weathering and the larger scale processes of the 1937 slide are hypothesized to cause the lower semivariance values of the 1937 slide at smaller scales

spatial and temporal analysis of a global landslide catalog abstract landslide inventories are critical to support investigations of where and when landslides have happened and may occur in the future however there is surprisingly little information on the historical occurrence of landslides at the global scale this paper presents a new publicly available global landslide catalog glc which is based on media reports online databases and other sources this database is currently available at http ojo streamer herokuapp com the 5741 points in the glc provide a foundation for evaluating spatial and temporal trends in landslide activity from 2007 to 2013 globally landslides were reported most frequently from july to september most events occurred in asia north america and southeast asia in contrast fewer than 5 of the fatalities were reported in north america suggesting a significant amount of under reporting in other regions as well as potential discrepancies between developing and developed regions reported landslide events were also compared to satellite based precipitation estimates from the tropical rainfall measuring mission trmm to evaluate the co occurrence of extreme precipitation and landslide activity of the 3550 points considered in a subset of the glc approximately 60 of the reported landslides have daily precipitation exceeding the 95th percentile of precipitation calculated over a 14 year trmm record for the same location this study also investigated how the recurrence interval of extreme precipitation corresponded to some of the most catastrophic landslide events in spite of several reporting and cataloging biases spatial and temporal analysis of the glc suggests that it is a valuable database for characterizing global patterns of landslide occurrence and evaluating relationships with extreme precipitation at regional and global scales