coastal dune ridge systems as chronological markers of palaeoseismic activity a 650 yr record from southwest new zealand a study of two shore parallel dune ridge sequences in southwest new zealand shows that tectonic activity has been the primary controlling influence in their formation since at least ad 1450 the timing of dune building episodes at the mouths of the haast and okuru rivers was determined using the ages of colonizing trees episodic dune formation was indicated by clear discontinuities in tree ages with distinct cohorts having colonized successive newly formed dune ridge swale units at both sites four dune ridge swale units have formed since ad 1450 with each unit closely postdating an alpine fault rupture c ad 1460 c ad 1615 ad 1717 ad 1826 colonizing cohorts of trees started growing within 20 46 years after an earthquake at both sites and all known major regional earthquakes have resulted in a dunebuilding episode no other dunes are present at either site progradational coastal dune systems have potential as a tool for palaeoseismic studies in regions with high background levels of sedime

paraglacial rock slope stability glaciation and deglaciation along with their associated climatic and non climatic processes modify slope stresses and influence slope stability paraglacial slope failures are those that are a part of or influenced by the transition from glacial conditions to non glacial conditions gravitational failure of rock slopes is a primary and dominant process of slope evolution in mountainous terrain and is the subject of this paper which 1 reviews the approaches taken for researching paraglacial rock slope failure patterns and processes 2 summarises the spatial and temporal patterns of post glacial failures 3 assesses the factors influencing slope stability during glaciation and deglaciation 4 explores some of the applications of paraglacial research and 5 highlights some of the outstanding issues to be resolved and provides recommendations for terminology relating to paraglacial slope processes

ice moraine and landslide dams in mountainous terrain we review recent work on ice moraine and landslide dams in mountainous terrain thus complementing several comprehensive summaries on glacier dams in intracontinental and arctic areas of low relief we discuss the roles of tectonic and climatic forcing on ice moraine and landslide dam formation and sudden drainage and focus on similarities and differences between their geomorphic impacts on confined valleys drained by steep bedrock and gravel bed rivers despite numerous reported failures of natural dams in mountain belts throughout the world their relevance to long term dynamics of mountain rivers remains poorly quantified all types of dams exert local base level controls thus trapping incoming sediment and inhibiting fluvial bedrock incision pervasive geomorphic and sedimentary evidence of outburst events is preserved even in areas of high erosion rates suggesting that sudden dam failures are characterized by processes of catastrophic valley floor aggradation active channel widening and downstream dispersion of sediment during which little bedrock erosion seems to be achieved we find that in the absence of direct evidence of former dams a number of similarities among the geomorphic and sedimentologic characteristics of catastrophic outburst flows may give rise to ambiguous inferences on the dam forming process this is especially the case for tectonically active mountain belts where there is ample and comparable potential for the formation and failure of ice moraine landslide and polygenetic dams concomitant with climatic oscillations or earthquake disturbance hence the palaeoclimatic implications of erroneously inferring the cause of dam formation may be significant we recommend that future research on natural dams in mountainous terrain addresses a climate and earthquake controlled systematics in the pattern of formation and failure b quantification of response of mountain rivers to catastrophic outburst events and their concomitant process sequences c elaboration of a comprehensive classification of natural dams in mountainous terrain with special attention to polygenetic dams d physical based modelling of dam formation failure and routing of water and sediment outbursts and e quantitative controls on the contribution of natural dams to sediment budgets in mountainous terrain

sediment budgeting a case study in the katiorin drainage basin kenya the primary objective of this study was to compute a detailed budget for a small semiarid tropical drainage basin in kenya results indicated that transfer of sediments inputs from primary source areas was minor in comparison to changes in storage the major sediment source area within the katiorin drainage basin was the colluvial hillslope zone the net change in storage within this zone was approximately 2100 mg yr 1 surface wash and rilling were the dominant transport processes responsible for the remobilization of colluvial sediments sediment storage within the in channel reservoir increased by 60 mg yr 1 which was minor when compared to the total store of sediment in this reservoir during 1986 the channel network stored only a small fraction 3 per cent of the sediment delivered from the hillslope subsystem therefore the in channel reservoir had limited influence on sediment conveyance to the basin outlet these data indicate that a static equilibrium condition cannot be assumed within the katiorin drainage basin such an assumption would result in erosion estimates of approximately 5 5 mm yr 1 for the entire basin based on a sediment output of 7430 mg km 2 yr 1 and a measured bulk density of 1 35 mg m 3 however this masked the actual rates of 1 2 to 7 1 mm yr 1 in subbasin primary source areas and rates of 0 6 to 17 mm yr 1 for colluvial material in the various subbasins the extreme accelerated erosion rates resulted from minimal ground vegetation steep slopes soil crust formation an erodible substrate and a well integrated drainage network for rapid conveyance of sediments from the hillslope subsystem to the basin outlet

prediction of the behaviour of landslide dams using a geomorphological dimensionless index landslide dams are a common phenomenon they form when a landslide reaches the bottom of a river valley causing a blockage the first effect of such a dam is the infilling of a lake that inundates the areas upstream while the possibility of a sudden dam collapse with a rapid release of the impounded waters poses a higher flood risk to the downstream areas the results of the main inventories carried out to date on landslide dams have been examined to determine criteria for forecasting landslide dam evolution with particular emphasis on the assessment of dam stability not all landslides result in the blockage of a river channel this only occurs with ones that can move a large amount of material with moderate or high velocities in most cases these landslides are triggered by rainfall events or high magnitude earthquakes a relationship also exists between the volume of the displaced material and the landslide dam stability several authors have proposed that landslide dam behaviour can be forecast by defining various geomorphological indexes that result from the combination of variables identifying both the dam and the dammed river channel further developments of this geomorphological approach are presented in this paper by the definition of a dimensionless blockage index starting with an analysis of 84 episodes selected worldwide it proved to be a useful tool for making accurate predictions concerning the fate of a landslide dam copyright 2002 john wiley sons ltd

holocene alluvial sediment storage in a small river catchment in the loess area of central belgium abstract soil erosion and sediment deposition widely affect landscape development particularly in erosion prone areas with loess derived soils nevertheless until now few attempts were made to quantify soil losses and sediment storage over long centennial or millennial timescales in this study the holocene alluvial sediment storage in a small river catchment 52 km2 of the belgian loess belt is estimated and a preliminary sediment budget for the catchment is presented in the valley of the nethen river c 13 km long a detailed survey of the alluvial sediment archive was conducted hand augerings and percussion drillings were made along cross valley transects at 12 locations in the catchment ams 14c dating of peat samples provided a temporal framework for the interpretation of the cores results show that the thickness of holocene sediment deposits in the nethen valley is 4 to 6 m which corresponds to a total clastic sediment mass of 14 106 t stored in the valley bottom three alluvial units could be distinguished and associated with deposition phases from 9600 to 2900 b c 2900 b c to a d 1000 and a d 1000 to present in contrast to the older sediments units 1 and 2 deposits from the last 1000 year unit 3 contain little organic matter they are seldom intercalated with peat layers and devoid of tufa unit 3 reaches a thickness of c 2 m thereby representing 50 of the holocene sediment mass stored in the alluvial plain the mean sedimentation rate in the alluvial plain for this last phase is 26 t ha 1 a 1 which is about tenfold larger than the sedimentation rates calculated for the older holocene sediment units sediment supply towards the alluvial plain has therefore increased tremendously since medieval times these results are in contrast to dating results obtained for colluvial sediments in a nearby dry valley within the catchment of the nethen where soil erosion and sediment deposition started in the early iron age and was already substantial during the roman age this means that there is a time lag of about one millennium between the onset of high sedimentation rates in the upstream area and high deposition rates in the alluvial plain this is probably caused by a change in coupling sediment connectivity between the plateau slopes and rivers as soil erosion proceeds first the dry zero order valleys in the catchment act as sediment traps and only after these are filled sediment reaches the floodplains the preliminary sediment budget for the nethen catchment illustrates that 50 of the sediment that was eroded during the holocene was stored in colluvial deposits which are mainly located on footslopes and in dry valley bottoms another 29 of the sediment mass is stored in the alluvial plain

300 mw baspa ii india s largest private hydroelectric facility on top of a rock avalanche dammed palaeo lake nw himalaya regional geology tectonic setting and seismicity article i nfo this study aims for the characterization of the geological setting of 300 mw baspa ii india s largest private hydroelectric facility which was built on top of a relict rock avalanche dammed palaeo lake baspa valley nw himalaya geologically the hydroelectric installation is located in the higher himalayan crystalline just above the active karcham normal fault which is reactivating the early miocene main central thrust one of the principal himalayan faults the area is seismically active and mass movements are common at ca 8200 yr bp the baspa river was blocked behind a 142 10

predictive uncertainty of peak outflow relations for landslides dam breach risk assessment development considering the failure of landslide dams often requires the estimation of peak outflow through the breach the empirical equations based on data from case studies tend to be the first direct approach this paper conducted an uncertainty analysis when these empirical relations were utilized to predict the peak outflow of a breached landslide dam the results suggest that the relations derived from manmade dams or embankments typically overestimate the peak outflow about 1 5 to 3 4 of an order of magnitude and the relations derived from the database of landslide dams have much smaller mean prediction errors and also exhibit broad uncertainty bands application of the uncertainly analysis was illustrated by the tangjiashan landslide dammed lake formed during 2008 wenchuan earthquake in addition the predicted results from eq 1 deduced herein were considered to be the reliable estimate of peak outflow through the breach of landslide dam

formation infill and dissection of a latest pleistocene landslide dammed reservoir betic cordillera southern spain upstream and downstream geomorphological and sedimentological evidence abstract a slope collapse in a narrow mountainous valley led to the formation of a latest pleistocene 14 500 cal bp lake dammed behind this mass movement deposit in the betic cordillera se spain the lithostructural conditions of the carbonate bedrock a warm and more humid period at the end of the last glaciation bolling interstadial and its location very close to a seismic mountain front provide the ideal context for the destabilization and failure of bedrock and the subsequent formation of this ephemeral mountain basin it was filled in 260 years estimated specific sediment yield ssy is at least two orders lower than ssy nowadays in se spain the calculated value of 81 t km2 y is similar to calculated values from artificial reservoirs in more humid and temperate drainage areas such as in central europe geomorphological and sedimentological features of the siltation of the landslide dammed reservoir have been preserved close to the betic cordillera mountain front the reservoir fill consists of over 30 m of lacustrine and alluvial deposits the lake created upstream of the landslide dam was silted by mainly terrigenous gilbert type delta gravels and turbiditic sands and mixed terrigenous bioclastic sedimentation horizontally laminated carbonate mudstones after the lake was silted a meandering river caused linear erosion over the natural dam and deeply dissected the lacustrine deposits above the river s pre landslide profile this process has allowed the study of the well preserved internal structure of the natural reservoir and identification of the stages in the construction and degradation of a semi closed basin the stages involved in the evolution of the landslide dammed reservoir may provide insights into studying the development of other closed or semi closed basins such as mountain basins or artificial dams

seven landslide dams of old seismic origin in southeastern sicily italy this paper focuses on origin morphology and evolution of seven landslide dams in southeastern sicily these landforms are part of a set of 146 landslides recently recognised in this area which was hitherto considered to have little or no slope instability southeastern sicily consists of a plateau the hyblaean mountains incised by canyons and surrounded by lower lands it is underlain mostly by subhorizontal moderately to well lithified carbonate rocks relief is low several lines of evidence justify the assumption of a seismic trigger for the landslides in this area 1 the geo climatic environment is not favourable to landsliding 2 low angle basal shear surfaces are very frequent 3 landslide distribution is consistent with the known magnitude distance relationships for earthquake induced landslides 4 historical documents testify to earthquake triggered slope instability and 5 a specific landslide can be exactly dated the phenomena illustrated here include six rock slides one with a debris flow component and one rock fall slip surfaces are mostly non circular landslide volume ranges from about 5010 3 to 3410 6 m 3 with reference to the costa and schuster geol soc am bull 100 1988 1054 classification of landslide dams five cases belong to type ii spanning the entire valley and two to type iv failures from both valley sides with frontal or side contact between failed masses with reference to crozier and pillans catena 18 1991 471 classification of landslide lakes all cases show a main valley lake while tributary valley back and supra lakes are sporadically present one damming is attributable to the 1693 earthquake with certainty another damming to the same earthquake with high probability three dams were reincised one breached or reincised one is slightly reincised and two more or less intact correspondingly five silting up deposits were reincised one is being reincised at present and two are still under formation d 2002 elsevier science b v all rights reserved

magnitude and frequency of landsliding in a large new zealand catchment knowledge of long term average rates of erosion is necessary if factors affecting sediment yields from catchments are to be understood without such information it is not possible to assess the potential influence of extreme storms and therefore to evaluate the relative importance of various components of a sediment budget a study of the sediment budget for the waipaoa catchment north island new zealand included evaluation of long term rates of landsliding for six landslide prone land systems in the catchment the number of landslides per unit area generated by each of several storms was counted on sequential aerial photographs and correlated with the magnitude of the corresponding storm the resulting relationships were combined with magnitude frequency relationships derived for storms from 70 to 100 year rainfall records in the area to estimate a long term magnitude frequency relationship for landsliding for each land system the long term average values of the areal landslide frequency number of slides per unit area per unit time were then calculated from these relationships the volumes of a sample of landslide scars were measured in the field and the proportion of slides that deliver sediment to channels was determined from aerial photographs these measurements then allowed calculation of the long term average rate of sediment production to streams from landslides for different land systems and types of vegetation results suggest that shallow landslides currently contribute about 15 5 of the suspended sediment load in the waipaoa river above the kanakanaia gauging station and that 75 of the sediment production from the landslides occurs during storms with recurrence intervals of less than 27 years reforestation of 6 3 93 km2 of the slide prone lands in the catchment between 1990 and 1995 resulted in a calculated decrease in slide derived sediment of 10 calculations suggest that reforestation of an additional 3 66 km2 of the catchment in areas with the most sensitive combinations of land system and storm regime could decrease the total sediment inputs from landsliding by about 20

active deformation of the pacific northwest continental margin tilted and uplifted marine terraces in southern oregon show progressive landward tilting of the coastal ranges at about 5 16 10 8 rad yr 1 for the last 0 25 m y tide gauges in washington and british columbia and ten resurveyed leveling lines running inland from the coast indicate contemporary landward down to the east tilt rates of about 1 12 10 8 rad yr 1 averaged over periods of from 10 to 50 years the leveling lines traverse and the terraces cut across dipping cenozoic strata pleistocene dips to 3 mio pliocene dips to 30 and eocene dips to 60 southern oregon from cape blanco to the siletz river shows geodetic or terrace tilting in the same direction as the underlying stratal dips hence present day deformation continues past deformation of the coastal ranges and is most likely related to active subduction of the juan de fuca plate the steep stratal dips lack of major active faults and historic earthquakes and presence of very young bedding plane faults suggest that much of the onshore deformation and shortening within the overlying north american plate is taken up by folding rather than thrust faulting present shortening rates across north trending folds near the coast are between 0 02 and 1 9 10 7 yr 1 the rate of shortening decreases rapidly eastwards from the juan de fuca north american plate boundary a total of about 25 mm yr 1 of permanent shortening could be occurring within the north american plate most of it in the westernmost 40 km the landward tilt and shortening rates are similar to those above many other subduction zones that have experienced great thrust earthquakes while a high strain rate measured near seattle washington has been interpreted as elastic strain accumulation before a thrust earthquake the low level of historic seismicity and the similarity of short and long term deformation rates suggest alternatively that the subduction beneath washington is aseismic the issue has considerable implications for seismic hazard evaluation in the pacific northwest and could be resolved by a search for the effects or lack of effects of prehistoric great earthquakes

dating the cooloola coastal dunes of south eastern queensland australia abstract the cooloola sand dunes are part of a series of aeolian parabolic dunes that stretch along the east coast of australia they form a chronosequence showing increasing weathering soil formation and water erosion across six geomorphically recognized soil landscapes these landscapes were recognized from air photographs and further refined on the basis of some 150 auger holes across the dunes data about the structure and floristics of the vegetation were collected at the same time there is a significant body of literature about the cooloola dunes but there are two areas that have not been satisfactorily considered first the previous dating which gave inconsistent results has been superseded by single grain osl dates and second cooloola has not been considered in a regional context here we report the results of single grain optically stimulated luminescence osl analyses for 31 samples for 21 sites across the geomorphic landscapes the sites were selected near the apex of each dune as this represents the last depositional date and the least disturbed by sand movement we recognized 10 units across the dunes on the basis of the dates available the dune ages ranged from recent to 725 ka the largest dunes at some 320 m high were dated at around 140 ka and these dunes carry the maximum vegetation biomass of this dunefield beyond this vegetation maximum the dunes had lost their parabolic shape due to prolonged weathering and erosion and the vegetation is greatly reduced in height and biomass the depth to the soil b horizon gradually deepens with age to form giant podzols in the older dunes the depth to the b horizon was remarkably consistent within the geomorphic landscapes across the length and breadth of the dunes these studies place the cooloola dunes in a unique position as the chronosequence is intact the possible processes that lead to the formation of the dunes and the regional implications are discussed secondly it shows the buildup and decline of the dune ecosystems and acts as a model for all ecosystems forest succession models which place less emphasis on soil development miss this important process

tephrochronologic constraints on temporal distribution of large landslides in northwest argentina abstract two morphologic settings in the northwestern argentine prone to giant mountain front collapse deeply incised narrow valleys and steep range fronts bordering broad piedmonts were analyzed through detailed investigations of fossil landslides and related fluvio lacustrine sediments nine different rhyodactic tephra layers were defined by geochemical fingerprinting of glass morphology of pumice stratigraphic relationships and mineralogy the age of three tephra could be determined either directly by 40ar 39ar dating or relatively by 14c dating of associated sediments paranilla ash documentclass aastex usepackage amsbsy usepackage amsfonts usepackage amssymb usepackage bm usepackage mathrsfs usepackage pifont usepackage stmaryrd usepackage textcomp usepackage portland xspace usepackage amsmath amsxtra usepackage ot2 ot1 fontenc newcommand cyr renewcommand rmdefault wncyr renewcommand sfdefault wncyss renewcommand encodingdefault ot2 normalfont selectfont decl

response of fluvial aeolian and lacustrine systems to late pleistocene to holocene climate change lower moravian basin czech republic abstract late pleistocene to holocene morava river valley fill of the eastern czech republic reflects the geomorphic evolution of the valley as forced by climate change valley fill stratigraphy was studied through measured sections optically stimulated luminescence osl and radiocarbon dating ground penetrating radar surveys of relict sand dunes archived drill hole data and a comparison of elevations and ages of stratigraphic units fluvial systems evolved from meandering with floodplains to braided during mis 3 braided fluvio aeolian systems dominated through mis 2 and the last glacial maximum lgm valley aggradation occurred during arid glacial times of a low water to sediment discharge ratio most valley fill was removed at 13 ka with incision by a large bend meandering river with an estimated bankful paleodischarge 3 larger than the modern morava river the holocene morava river has varied from meandering to anabranching with low rates of floodplain aggradation the bzenec sand body up to 36 m thick represents an erosional remnant bypassed during late pleistocene incision and consists of interpreted lacustrine turbidites overlain by braided stream and aeolian dune strata the turbidites consist of laterally continuous thin normally graded beds of rounded and frosted sand grains of aeolian origin dates and elevation data argue that the valley lake formed during the lgm through downstream damming by a braided terminal fan and sand dune complex the turbidites are interpreted to have formed through fluvial undercutting and slumping of dune accumulations as lake level rose this process forced an erosional unroofing of aeolian accumulations reflected in inverted osl dates for the turbidites

analysis of landslide dams induced by the 2008 wenchuan earthquake abstract landslide dams caused by earthquakes are extremely hazardous disruptions of the flow of water and sediment in mountain rivers capable of delivering large outburst floods that may devastate downstream areas we analyzed a unique inventory of 828 landslide dams triggered by the m w 7 9 2008 wenchuan tectonic earthquake china constituting 1 4 of the 60 000 coseismic slope failures mapped and attributed to this event while 501 landslides blocked the rivers completely the remainder caused only partial damming or channel diversion the spatial distribution of landslide dams follows the same trend of that of the total landslide distribution with landslide dams being most abundant in the steep watersheds of the hanging wall of the yingxiu beichuan thrust fault and in the northeastern part of the strike slip fault near qingchuan besides the co seismic landslide density the river width also played a key role in determining the landslide dam formation narrow rivers are more prone to be dammed than the wide rivers the correlation between river width and landslide dam volume follows a linear relation which can be used to roughly estimate the dam formation possibility however the applicability of this correlation needs to be validated in other regions the decay failure rate of dams defined here as the percentage of the number and area of landslide dams that have failed over time shows that 25 of dams accounting for 30 of total landslide dam area failed one week after the earthquake these percentages increased to 60 within 1 month and to 90 within 1 year the geomorphometric parameters were analyzed revealing power law relations between landslide area and dam width landslide source area and dam area as well as lake area and lake volume the inventory presented in this study will enrich the worldwide earthquake induced landslide dam database and will also contribute to a better understanding of the post earthquake dam decay

a source to sink perspective of the waipaoa river margin abstract a fundamental goal of the earth science community is to understand how perturbations on earth s surface are preserved in the stratigraphic record recent source to sink s2s studies of the waipaoa sedimentary system wss new zealand are synthesized herein to provide a holistic perspective of the processes that generate transport and preserve sedimentary strata and organic carbon on the waipaoa margin in the late quaternary rapid uplift associated with subduction processes and weak sedimentary units have conspired to generate rapid rates of incision and erosion in the waipaoa catchment since the last glacial maximum lgm we show that although much of the sediment exported offshore during this time interval originated from valley excavation a substantial portion emanated from hillslopes mostly through deep seated landslide and earthflow processes that were vigorous during periods of rapid fluvial incision just prior to the pleistocene holocene transition lacustrine sediments deposited in naturally dammed 7 ky old lake tutira provide a record of holocene environmental controls on upper catchment sedimentation in the wss with 1400 storms identified storm frequency is modulated by the waxing and waning of atmospheric teleconnections between the tropics and antarctica furthermore clear long term changes in sediment yield are evident from the lake tutira record following human settlement as conversion to pasture is accompanied by a 3 fold increase in the long term lake sediment accumulation rate whereas there is ample evidence that waipaoa river flood deposits are routinely deposited offshore in the sheltered confines of poverty bay over the longer term waves and currents subsequently resuspend and transport these deposits both landward sandy fraction and seaward finer fraction thus the timing of sediment supply to areas of net sediment accumulation is more often driven by wave events that are not associated with river flooding therefore we conclude that asynchronicity of river sediment delivery and of wave resuspension in most instances precludes the direct preservation of flood events in the stratigraphic record of the waipaoa shelf over the longer term the sediment package preserved on the shelf and slope since the lgm can be explained in large measure by sequence stratigraphic models forced by varying sea level and ongoing tectonic deformation of the margin as sea level rose sediment supply to the slope was reduced by about a factor of 5 due to shelf trapping despite this reduction turbidites are found at similar frequency throughout the lgm present as the dominant trigger appears to be subduction earthquakes with large ones having a return interval of about 200 100 years sediment budget exercises that consider both modern river discharge versus centennial accumulation rates and post lgm terrestrial production versus offshore isopachs mass balances indicate that about half of the total sediment production from the waipaoa escapes the study area moreover a coupled sediment transport hydrodynamic model and observations of textural trends on the shelf indicate that a large fraction of the sediment is carried outside the study area along the shelf to the northeast by the river plume or by combined current wave activity therefore we conclude that the wss is an open system with sediment escape from the present day through the lgm the organic matter associated with sediment as it moves from upland source to marine sink is a product of particle history and provides a record of materials that have cycled over timescales of days to millions of years the ubiquity of fossil organic carbon oc in both the terrestrial and marine realms of the waipaoa attests both to the chronic nature of its source crumbling mudstones further destabilized by land use and its biogeochemical recalcitrance modern oc persists by virtue of its continual production along the s2s transit and is buried and preserved within the adjacent marine depocenters the waipaoa contrasts with dispersal systems on wide energetic shelves e g the amazon and fly rivers where sediment is extensively refluxed in oxygenated overlying water resulting in the biogeochemical incineration of particulate oc the waipaoa like other small mountainous rivers on active margins exhibits a high riverine oc preservation efficiency 50 in its marine depocenters because of the relatively rapid event driven accumulation of sediment

palaeolithic landscapes of europe and environs 150 000 25 000 years ago an overview abstract when considering the evolution and migrations of neandertalers and early modem human beings the harsh conditions of the last glacial maximum are often implicitly or explicitly assumed as their environmental background this perception is false the conditions of the high glacial apply to a small fraction of late pleistocene time here we review the palaeoenvironmental history of europe from 150 000 to 25 000 years ago with the aid of data from long cores of ice and marine and continental sediments the results are displayed in four sketch maps that illustrate the landscapes of an interglacial glacial cycle the maps connected by palaeoenvironmental histories show that especially between 60 000 and 25 000 years ago a critical part of the palaeolithic the glacial landscapes were for much of the time less barren than is generally assumed but numerous climate changes on a scale of several millennia are evident placing a premium on accurate dating of the co evolution of humans and landscape moreover during the glacial interval abrupt climatic changes lasting from a century to a few millennia were common their importance for landscape changes and their impact on human activity remain to be ascertained

age estimates for the late quaternary high sea stands abstract a database of more than 300 published alpha counted uranium series ages has been compiled for coral reef terraces formed by late pleistocene high sea stands the database was screened to eliminate unreliable age estimates 230 th 232 th 5 and those without quoted without quoted errors and a distributed error frequency curve was produced this curve can be considered as a finite mixture model comprising k component normal distributions each with a weighting by using an expectation maximising algorithm the mean and standard deviation of the component distributions each corresponding to a high sea level event were estimated eight high sea stands with mean and standard deviations of 129 0 33 0 123 0 13 0 102 5 2 0 81 5 5 0 61 5 6 0 50 0 1 0 40 5 5 0 and 33 0 2 5 ka were resolved the standard deviations are generally larger than the values quoted for individual age estimates whilst this may be due to diagenetic effects especially for the older corals it is argued that in many cases geological evidence clearly indicates that the high stands are multiple events often not resolvable at sites with low rates of uplift the uranium series dated coral reef terrace chronology shows good agreement with independent chronologies derived for antarctic ice cores although the resolution for the latter is better agreement with orbitally tuned deep sea core records is also good but it is argued that isotope stage 5e is not a single event as recorded in the cores but a multiple event spanning some 12 ka the much earlier age for isotope stage 5e given by winograd et al 1988 is not supported by the coral reef data but further mass spectrometric uranium series dating is needed to permit better chronological resolution

eustatic and tectonic controls upon quaternary coastal sedimentation in the corinth basin greece the late quaternary sedimentology and palaeogeography of the corinth isthmus in central greece is re interpreted a series of beach to shoreface sub sequences are seen each characteristically having an overall fining up character these occur within a coastal facies belt which has prograded to the west computer modelling illustrates the interaction of tectonic displacements and eustatic sea level variation as controls of facies patterns late pleistocene holocene facies geometries are predicted on the basis of published sea level data over that time interval on coastlines undergoing tectonic uplift such as the isthmus of corinth depositional patterns may be characterized by transgressive wedges these sub sequences merge basinwards below sea level minima each transgression relates to a major eustatic sea level peak such first order models are modified by variations in the rate of tectonic deformation the second control on relative sea level position modelled facies patterns are tested on the basis of new 230 th 234 u dates obtained from sclerac tinian corals of the corinth canal area dated sub sequence sediments correspond in age to late pleistocene eustatic highs and observed facies patterns correlate with the major late pleistocene holocene eustatic transgressions of c 100 ka periodicity episodes of intrabasinal normal faulting are isolated from a structural history otherwise dominated by uplift across the isthmus quantification of post depositional vertical tectonic displacements is achieved constraining the eustatic base level at the time of deposition of a dated horizon by reference to the global late quaternary sea level curve the original depositional level is then subtracted from the present outcrop level using available 230 th 234 u dates to establish syn depositional base levels minimum uplift rates of the order of 0 3 m ka 1 are calculated across the area averaged through the late pleistocene and holocene

the last interglacial shoreline in australia a review abstract marginal marine strata of last interglacial age occur in a range of morphostratigraphic settings around the australian coastline the lithofacies are similar to their holocene equivalents but are partly lithified elevated and laterally displaced inland uranium series ages for corals and molluscs from widely separated localities around the australian coastline are generally in accord with the accepted age for oxygen isotope substage 5e 125 000 10 000 bp the value generally accepted for the last interglacial maximum amino acid racemisation has principally been applied to correlation of sequences with benchmark sites dated by the uranium series method elevations of preserved last interglacial shorelines do not support the notion that australia is a stable continent significant neotectonic anomalies include cape cuvier 10 5 m fleurieu peninsula 6 m the coorong coastal plain 10 m and tasmania 32 m each indicating contrasting degrees of local uplift the tasmanian sequences are the highest occurrence on the australian continent and have been attributed to uplift as a result of mantle hotspot processes with the exception of these tectonically uplifted sites the height of the last interglacial sea surface around the australian coastline is consistently below the 6 m level globally attributed to this high sea level stand in australia the most consistent datum is from western eyre peninsula where a level 2 m above present mean sea level is ubiquitous the more southerly limit of coral growth and wider distribution of subtropical molluscan fauna are in accordance with warmer ocean waters during substage 5e approximately 2 c the extent of racemisation in molluscan fossils from southern australia also excludes the possibility of a more equable latitudinal distribution of mat during substage 5e

transient water and sediment storage of the decaying landslide dams induced by the 2008 wenchuan earthquake china article earthquake triggered landslide dams are potentially dangerous disrupters of water and sediment flux in mountain rivers and capable of releasing catastrophic outburst flows to downstream areas we analyze an inventory of 828 landslide dams in the longmen shan mountains china triggered by the mw 7 9 2008 wenchuan earthquake this database is unique in that it is the largest of its kind attributable to a single regional scale triggering event 501 of the spatially clustered landslides fully blocked rivers while the remainder only partially obstructed or diverted channels in steep watersheds of the hanging wall of the yingxiu beichuan fault zone the size distributions of the earthquake triggered landslides landslide dams and associated lakes a can be modeled by an inverse gamma distribution b show that moderate size slope failures caused the majority of blockages and c allow a detailed assessment of seismically induced river blockage effects on regional water and sediment storage monte carlo simulations based on volumetric scaling relationships for soil and bedrock failures respectively indicate that 14 18 of the estimated total coseismic landslide volume of 6 4 14 6 10 9 m 3 was contained in landslide dams representing only 1 4 of the 60 000 slope failures attributed to the earthquake these dams have created storage capacity of 0 6 10 9 m 3 for incoming water and sediment about 25 of the dams containing 2 of the total river blocking debris volume failed one week after the earthquake these figures had risen to 60 20 and 90 90 within one month and one year respectively thus also emptying 92 of the total potential water and sediment storage behind these dams within one year following the earthquake currently only 0 08 10 9 m 3 remain available as natural reservoirs for storing water and sediment while 0 19 10 9 m 3 i e about a third of the total river blocking debris volume has been eroded by rivers dam volume and upstream catchment area control to first order the longevity of the barriers and bivariate domain plots are consistent with the observation that most earthquake triggered landslide dams were ephemeral we conclude that the river blocking portion of coseismic slope failures disproportionately modulates the post seismic sediment flux in the longmen shan on annual to decadal timescales

post deforestation soil loss from steepland hillslopes in taranaki new zealand soil erosion on steepland hillslopes in taranaki new zealand where landsliding is the dominant erosion form was investigated by comparing mean regolith depths between first order basins that have had their forest cover removed for different periods of time regolith depth and slope angle data were collected along 19 profile lines and 30 profile lines from steepland basins that had been deforested for 10 and 85 years respectively these profile lines were subdivided into a total of 236 profile segments of relatively linear slope angle and uniform regolith depth that averaged 17 5 m in length the depth of pre existing regolith on post deforestation landslide sites is estimated from a regression of regolith depth on slope angle for undisturbed non landslide profile segments regolith depletion on landslide sites is in turn estimated by subtracting the depth of regolith on landslide sites from the estimate of pre existing regolith depth regolith depletion by post deforestation landslides averaged over the entire length of profile lines gives an estimate of average surface lowering for the area deforested for 85 years average surface lowering by post deforestation landslides is 0 15 0 04 m and is the same as the difference in mean depth of 0 15 0 11 m between this area and the area deforested for 10 years erosion of regolith from hillslopes by processes other than landsliding appears to be minimal the 0 15 m average surface lowering represents a regolith depletion rate of 1 8 0 5 mm yr 1 for hillslopes steeper than 28 where all post deforestation landslides occur average surface lowering is 0 20 0 05 m and the regolith depletion rate is 2 4 0 6 mm yr 1 average surface lowering is greatest at 0 23 0 07 m on hillslopes steeper than 32 where most post deforestation landslides occur here the regolith depletion rate is 2 7 0 8 mm yr 1 a large magnitude low frequency storm in march 1990 produced an average surface lowering of 0 041 m there were proportionately more landslides in the area deforested for 10 years illustrating the importance of previous erosion history of hillslopes on the spatial distribution of landslides there were also comparatively few landslides on steeper hillslopes because previous lower magnitude storms had already removed much of the deeper regolith

floodplain evolution in a small tectonically active basin of northern california sediment cores were collected along oodplains in the navarro river basin of coastal northern california to examine the controls on oodplain evolution in a tectonically active setting sedimentary strata were subsampled for organic content bulk density and grain size measurements organic samples were analysed for 14c age which yielded net averaged sedimentation rates for all cores overbank deposition rates decreased at all study sites through time and declined in the downstream direction the ability of intermediary order streams to store sediment in oodplains decreased the ability of highest order streams to record sediment pulse events the effects of anthropogenic disturbance primarily logging on long term overbank deposition rates were minimal climatic variability by affecting sediment loading in the channel network is the principal control on oodplain evolution through the holocene a hypothetical model is proposed to explain overbank deposition rates in the navarro basin which may be extrapolated to the northern coastal california region during the late pleistocene and holocene the complexities observed in sediment storage and routing in this study imply that caution should be made when extrapolating sediment yield measurements obtained at river mouths or coastal shelves to geomorphic events within small tectonically active basins

chronology of a probable neotectonic pleistocene rock avalanche cordon del plata central andes mendoza argentina abstract placetas amarillas 1 rock avalanche located at 32 43 s 69 25 w was geomorphologically stratigraphically and chronologically studied this extraordinary event dammed a secondary gully causing the formation of a barrier lake indicated by relict lacustrine and diatomite deposits stratigraphically its deposit is overlain by alluvial fans where three tephra layers are intercalated dating using ar ar method of the middle ash level at 350 80 ka determined a middle pleistocene or older age for this event furthermore the younger age of placetas amarillas 2 is established by relative dating techniques such as soil development and rock varnish development the ages established in this research indicate that placetas amarillas 1 may be temporally correlated with the tigre dormido rock avalanche suggesting that the occurrence of these rock avalanches may be related to regional neotectonic activity nevertheless climatic conditions are not underestimated as the tigre dormido event occurred before formation of an outwash terrace related to a glaciation of early middle pleistocene age

some methodological developments in the analysis of sediment transport processes using age distribution of floodplain deposits abstract floodplain areas are primary storage sites for river sediment in the saru river ages of floodplain surfaces were examined by tree ring analysis and vertical and horizontal configurations of floodplain deposits were measured by field and aerial photo surveying a flood in 1992 provided a good opportunity to examine depositional and erosional processes of floodplain sediment before and after the flood predominant disturbances were observed in the unconstrained wide reaches where floodplains develop this event indicated that eroded areas of floodplain deposits in each age class linearly increased with sediment volume and that the proportion of the total area eroded decreased exponentially with increase in the age of sediment we constructed basic equations expressing continuity of age distribution in order to analyze river sedimentation in a time series according to the results of the 1992 flood the floodplain disturbance rates determined by this analysis showed similar temporal changes with sediment transport rates monitored at the iwachishi reservoir a sharp increase in sediment discharge was seen after 1962 associated with the historical maximum rainfall in the temporal analysis of floodplain sediment the time series approach presented here is useful for evaluating the speed of sediment waves and the cumulative impact of sedimentation in a river basin

analyzing successive landslide dam formation by different triggering mechanisms the case of the tangjiawan landslide sichuan china abstract the catastrophic tangjiawan landslide triggered by the 2008 wenchuan earthquake blocked the duba river impounding one of the most dangerous coseismic barrier lakes in beichuan china the lake was drained by an artificial spillway within one month after the earthquake to minimize the potential dam breach flooding risk however on september 5 2016 this landslide was reactivated and dammed the river again creating a 20 m high dam at the same location and resulting in the formation of a barrier lake with a volume of 0 6 million m3 the day after the event we carried out a field investigation of the landslide and obtained a high resolution image and dem using uav the satellite images from 2005 2008 2010 and 2015 were also collected to analyze the evolution of the landslide together with multi temporal dems the geometry and volumes of the displaced mass and the landslide dams and barrier lakes were calculated using image interpretation and 3d spatial analysis with gis this landslide is of great scientific interest as it presents a good example of multiple reactivation of a pre historical giant landslide under different triggering conditions a reactivation of an older landslide during the wenchuan earthquake and a second reactivation during a rainfall event several years later meanwhile from the hazard assessment and prevention perspective it is also representative as it dammed the river twice in 2008 and 2016 posing threats to both upstream and downstream areas we infer that the successive landslides in this region could be caused by the strong tectonic activities including earthquakes and high average uplifting rate the results of landslide volume analysis using multi temporal dems contribute to the landslide mechanism analysis and suggest that the landslide volume estimation is effected by the landslide type landslide rupture surface location and resolution of dem we also compare the performance of different empirical models of landslide stability and dam breach flood parameters and discuss their application during the quick assessment of the potential hazard of the landslide dams generally the successive landslide dams at the tangjiawan site are caused by the successive landslide reactivations on an anti dip slope controlled by strong tectonic activity and river erosion involve with a mass of loose materials of previous landslide deposition and possess high flood risk to the downstream area the experience gained in this work can be used to assist the hazard assessment and the planning of the emergency measures for similar landslide dams in the future

holocene sedimentary record from lake tutira a template for upland watershed erosion proximal to the waipaoa sedimentary system northeastern new zealand abstract a holocene lake record from northeastern new zealand provides a detailed record of environmental controls on upper watershed sedimentation and is proximal to the waipaoa margins source to sink focus site in that context lake tutira in hawke s bay was cored in 2003 to recover a complete sedimentary record since the lake s formation ca 7 2 ka the 27 14 m long core contains alternating lithotypes that are sedimentary responses to lacustrine organic accumulation normal to severe rainfalls earthquakes and volcanism a diatom allochthonous ranking scheme pollen counts and c and n percentages were used to identify intra lake and watershed derived storm deposits and modes of lithotype deposition the lithotypes and depositional modes are tephras volcanic airfall organic rich mud algal rich lake sedimentation massive to weakly graded brown silty clay beds homogenites and redeposited lake sediments grey graded sandy mud beds intense storm delivered sediment and thin yellow clay layers run off from small storms using 12 tephras and 3 radiocarbon ages to provide a chronology the long term sedimentation rate is ca 3 3 mm year which increases to 10 mm year following european colonisation storm beds occur in response to rainfall events with no obvious correlation to el nino southern oscillation polarity or strength moreover no single climate index appears to correlate strongly with the historic rainfall event record having characterised and identified storm beds over the lake s history a hindcast relationship implies that around 53 pre historic storms occurred with a magnitude similar to the severe cyclone bola event of 1988 plus 7 potentially larger storm events despite the prominence of storm beds a summation of the total percent thickness as an indication of the relative modes of emplacement for each lithotype shows that proportionally the balance of intra lake versus storm sources preserved in the lake bed is 69 and 26 respectively as well as storms lake sedimentation is strongly influenced by earthquakes that destabilize the terrigenous sediment laden lake margins to generate homogenites represented by the brown silty clay beds these deposits tend to be thicker after a hiatus in seismic activity and after sustained periods of lake margin loading as inferred from the occurrence of thick graded storm beds comparison with marine records on the adjacent continental margin suggests that more terrestrial events are captured in the lake record due to i close hillslope lake connectivity with little intervening storage of sediment compared with the waipaoa sedimentary system and ii the preservation of event stratigraphy at tutira compared to its reduced preservation in the dynamic marine environment only major storms such as cyclone bola leave an imprint traceable to the ocean whereas identifiable sedimentary responses to individual earthquakes are localized although through landscape preconditioning and sediment production they contribute to the overall high terrigenous input to the ocean in contrast low frequency high magnitude perturbations volcanic eruptions european deforestation are preserved through the source to sink sedimentary system consistent with earlier hypotheses

application of tree ring analysis to paleoseismology knowledge of the seismicity for a region is one of the keys to estimating earthquake hazards unfortunately historical records are generally inadequate for evaluations of seismicity paleoseismology addresses this problem using various techniques for determining the times and locations of earthquake disturbances trees with widespread geographical distribution identifiable annual growth increments and sensitivity to environmental changes can provide an almost unique tool for dating past earthquake events geomorphic and hydrologic changes and dynamic stress resulting from earthquakes can cause a variety of effects in trees and communities of trees tree ring analysis can 1 produce the actual year and sometimes the season for disturbance events and 2 establish synchronicity for events that may be beyond the range of absolute calendar dating tree ring dating or dendrochronology is used to establish exact dates based on patterns of annual ring variations through time mere counting of rings is inadequate and may lead to errors in assigning dates to rings because of possible missing micro or false rings trees ranging in age from 300 500 years grow in many places and can be used to identify previously unknown seismic events or to better define events that are partially known longer time spans can be covered in some instances earthquakes may be more precisely located in space and time or have their magnitudes and displacements better estimated by analysis of tree rings a number of studies have established the validity of tree ring application to paleoseismology but only a few studies have contributed new information to the paleoseismic record a review of the application of tree ring analysis to paleoseismology is in jacoby 1997 the science should now move from the discovery phase to a wider application phase successful applications will add important information to the records of seismicity and the evaluation of earthquake hazards

comparison of rock failure criteria in predicting borehole shear failure abstract selection of the appropriate rock failure criteria is one of the key steps in determining minimum required mud weight in wellbore stability analysis numerous failure criteria have been used for rock failure analysis but there is no common agreement of which failure criterion to select in this paper thirteen failure criteria used in predicting borehole shear failure were evaluated for four field cases in a comparison of the results with actual field failure cases tresca von mises and inscribed drucker prager overestimated the rock breakout and predicted the highest required minimum required mud weight for all cases also the results of these criteria are significantly higher than the actual borehole shear failure circumscribed drucker prager underestimated the rock breakout and predicted the lowest bound of the minimum required mud weight in most cases which is mainly less than actual onset of borehole breakout the minimum required mud weights determined by modified lade modified wiebols cook and mogi coulomb is above but close to the onset of breakout based on the field reported failure cases this means that using of any of these three criteria in wellbore stability analysis could be a safe approach furthermore modified lade modified wiebols cook and mogi coulomb provided similar results for all studied cases so these failure criteria may be used interchangeably

cosmogenic dating of rock avalanches constraining quaternary stratigraphy and regional neotectonics in the argentine central andes 32 s abstract this paper provides a comprehensive review of the chronostratigraphy of six rock avalanches clustered in the northern extreme of the cordon del plata range these rock avalanches are stratigraphically related to pleistocene glacial drifts and valley fill deposits documenting the regional neotectonic activity we used cosmogenic dating tcn to directly date block surfaces of rock avalanche deposits as well as optically stimulated luminescence dating osl of paleo lakes dammed by these rock avalanches our new direct dates 17 tcn and 4 osl determine the middle to late pleistocene age of these collapses these are in contrast to the previously established chronostratigraphy based on relative dating techniques paleontological context and tephrochronology these new data help to redefine the geomorphological evolution of the mendoza river valley especially the new data indicate that the glacial stratigraphy earlier proposed must be reconsidered we redefine this stratigraphy as far as possible with our data and discuss the data in relation with other recently published results however it becomes clear that the glacial history of the mendoza valley has to be studied anew by using modern dating techniques in addition our data suggest that the carrera fault system bounding the valleys of the cordillera del plata has been active more recently than proposed earlier

analysis of hillslope erosion rates using dated colluvial deposits hollows are sites of long term deposition of colluvium and contain a valuable record of the timing and rates of hillslope erosion a model is presented that uses measured depositional rates of colluvium in hollows to calculate transport rates of colluvium and bedrock lowering rates on the surrounding slopes this model has been applied to eight dated colluvial deposits in the clearwater river basin of western washington the calculated average transport rate is about 34 cm 3 cm yr and the calculated average bedrock lowering rate is about 0 04 mm yr equivalent to an average sediment yield of 90 t km 2 yr for the holocene there is significant variability in erosion rates between sites which may be due to local lithologic variations although the average values are similar to an independent estimate of modern erosion rates for this area multiple stratigraphic levels have been dated in five deposits and document that the deposits are cumulative and that deposition has been active through the

empirical prediction of coseismic landslide dam formation in this study we develop an empirical method to estimate the volume threshold for predicting coseismic landslide dam formation using landscape parameters obtained from digital elevation models dems we hypothesize that the potential runout and volume of landslides together with river features determine the likelihood of the formation of a landslide dam to develop this method a database was created by randomly selecting 140 damming and 200 non damming landslides from 501 landslide dams and 60 000 landslides induced by the mw 7 9 2008 wenchuan earthquake in china we used this database to parameterize empirical runout models by stepwise multivariate regression we find that factors controlling landslide runout are landslide initiation volume landslide type internal relief h and the h l ratio between h and landslide horizontal distance to river l in order to obtain a first volume threshold for a landslide to reach a river the runout regression equations were converted into inverse volume equations by taking the runout to be the distance to river a second volume threshold above which a landslide is predicted to block a river was determined by the correlation between river width and landslide volume of the known damming landslides the larger of these two thresholds was taken as the final damming threshold this method was applied to several landslide types over a fine geographic grid of assumed initiation points in a selected catchment the overall prediction accuracy was 97 4 and 86 0 for non damming and damming landslides respectively the model was further tested by predicting the damming landslides over the whole region with promising results we conclude that our method is robust and reliable for the wenchuan event in combination with pre event landslide susceptibility and frequency size assessments it can be used to predict likely damming locations of future coseismic landslides thereby helping to plan emergency response copyright 2014 john wiley sons ltd

palaeoseismicity and de geer moraines abstract de geer moraines are small moraine ridges formed partly in crevasses at the base of glacier ice there may be several different origins of the crevasses one possibility proposed by gerard de geer who first studied these ridges was seismic activity in connection with the isostatic rebound during the deglaciation the present study shows a close connection between occurrences of de geer moraines in fennoscandia and seismic activity or fresh looking fault lines and other features indicating neotectonic movements this supports de geer s theory but does not exclude formation in crevasses formed in other ways there is no real proof that the tectonic movements took place in the quaternary but the close connection between the moraines and tectonic features is evidence pointing in this direction if this is correct it has important implications for the stability within cratons of precambrian crystalline bedrock

36cl terrestrial cosmogenic nuclide dating suggests late pleistocene to early holocene mass movements on the south face of aconcagua mountain and in the las cuevas horcones valleys central andes argentina

effects of the internal structure of a rock avalanche dam on the drainage mechanism of its impoundment flims sturzstrom and ilanz paleo lake swiss alps abstract the holocene sturzstrom of flims grisons switzerland mobilized 12 km3 of jurassic limestone making it one of the largest events of this kind on the earth the material dammed a 10 km long reach of the upper rhine river valley with thicknesses up to 400 m a 40 km long natural lake was formed upstream the body of the avalanche deposits displays a well preserved internal fabric five major sedimentary facies were identified related to the confinement of the deposits in a narrow valley that restricts the spreading of transported material in the deepest parts of the avalanche deposit a stratified facies attests that the movement was mainly non turbulent whereas a granular facies appears in the lateral and upper parts the relative position of these facies within the natural dam has played an important role in the way the water flow eroded the dam crest and emptied the lake as suggested by the present valley slope morphology ledges corresponding to the levels of the different facies on north and south slopes of the valley correspond to steps in the narrowing of the incision the outburst of the dam if it occurred only affected the upper part of the deposits that corresponds to the poorly cohesive granular facies one hundred kilometres downstream in lake konstanz bodensee lacustrine sediments the presence of two layers contrasting with the normal grey varved deposits and separated by six laminites are contemporaneous with the mass movement these layers which could correspond to the outburst of the dam point to not one but two major overflooding events

podzol chronosequences on coastal dunes of eastern australia chronosequences of freely drained podzols formed in extensive dune systems of quartz sands along the east coast of australia offer unique opportunities for comparing temporal changes in different climatic zones during the late quarternary the largest areas and greatest number of dune systems occur along the subtropical coast near brisbane here parts of six dune systems have not been covered by younger deposits and have been exposed to weathering since deposition these areas constitute a relative age sequence on which podzols have formed with solum depths varying with age from 20 m absolute ages for each system have not been determined but differences in erosion and weathering depths and comparisons with dated dunes elsewhere along the coast indicate an age sequence extending back at least to the last interglacial similarities in geomorphology and soils enable correlation with dune systems in other areas to the north and south and so provide a greater potential for examining temporal changes in soils and biological systems than that of previous soil chronosequences1 5

investigation of earthquake triggering for deep seated landslides taranaki new zealand because large earthquakes can trigger landslides the landslide record has potential use for establishing the palaeoseismicity of a region however before this potential can be realized other possible landslide triggering mechanisms must be investigated in southeastern taranaki new zealand over 100 deep seated complex rock slumps occur in a region of steeply dissected gently dipping pliocene marine sediments three age populations can be detected by using relative and radiometric dating methods the youngest group of landslides displays a consistent depth of soil development lacks an integrated drainage network dams catchments to produce lakes and has well defined mass movement features this group covers an area of 1015 km2 yields radiocarbon dates of around 1300 bp and is clearly distinguishable from the two older groups of landslides the synchronicity of landslide formation over a wide area before new zealand was populated rules out human factors and slope undercutting as triggering agents comparison with modern analogues also rules out rainstorm as a triggering agent principally on the basis of depth of movement the distribution of landslides and the amount of failed surface is shown to be closely related to the location of active fault traces the increase in landsliding towards the fault cannot be explained by variation in lithology or structure limiting equilibrium analysis of one landslide further points to the need for earthquake shaking to induce movement together the lines of evidence investigated provide a strong case for earthquake triggering of prehistoric landslides in this region

hillslope response to climate modulated river incision in the waipaoa catchment east coast north island new zealand quantifying how hillslopes respond to river incision and climate change is fundamental to understanding the evolution of uplifting landscapes during glacial interglacial cycles we investigated the interplay among uplift river incision and hillslope response in the nonglacial waipaoa river catchment located in the exhumed inner forearc of an active subduction margin on the east coast of the north island of new zealand new high resolution topographic data sets light detection and ranging lidar and photogrammetry combined with field mapping and tephrochronology indicate that hillslopes adjusted to rapid latest pleistocene and holocene river incision through the initiation and reactivation of deep seated landslides in the erodible marine sedimentary rocks of the waipaoa sedimentary system postincision deep seated landslides can occupy over 30 of the surface area the ages of tephra cover beds identified by electron microprobe analysis on 80 tephra samples from 173 soil test pits and 64 soil auger sites show that 4000 5000 yr after the initiation of river incision widespread hillslope adjustment started between the deposition of the ca 14 000 cal yr b p waiohau tephra and the ca 9420 cal yr b p rotoma tephra tephrochronology and geomorphic mapping analysis indicate that river incision and deep seated landslide slope adjustment were synchronous between main stem rivers and headwater tributaries hillslope response in the catchment can include the entire slope measured from river to ridgeline and in some cases the interfluves between incising subcatchments have been dramatically modified through ridgeline retreat and or lowering using the results of our landform tephrochronology and geomorphic mapping we derive a conceptual time series of hillslope response to uplift and climate change induced river incision over the last glacial interglacial cycle

geomorphometric characteristics of new zealand landslide dams abstract this study presents results from a quantitative analysis of a new inventory of n 232 landslide dam occurrences in new zealand previously published data were expanded by documentation of recent events and evidence from a regional air photo reconnaissance focused on the upland regions of southwestern south island additional geomorphometric data on landslide dams associated lakes and contributing catchment characteristics were extracted from a 25 m digital elevation model dem augmented by limited ground truthing and compiled in a gis based inventory the new zealand case examples fall into the global trend although they contain both two extremely large features in terms of landslide dam volume vd and lake volume vl analysis suggests that landslide dam height hd landslide dam volume vd lake volume vl contributing catchment area ac and local relief hr are key variables for assessing landslide dam stability independently from other catchment parameters such as lithology climate or dam sedimentology they may be provisionally used as representative characteristics of landslide dams irrespective of environmental boundary conditions such as climate geology or site specific valley geomorphometry three newly proposed dimensionless indices i e the backstow index is basin index ia and relief index ir based on landslide dam height hd allow limited yet promising preliminary assessments of landslide dam stability compared with worldwide examples they also demonstrate a much narrower conditional range for the formation of stable landslide dams in new zealand catchment parameters such as maximum elevation emax upstream relief hr contributing catchment area ac and relief ratio rr are significantly different at sites of former and existing landslide dammed lakes and may be used as independent variables in future terrain based classification schemes generally data are incomplete with underreporting of small and ephemeral landslide dams and over representation of earthquake case studies nonparametric correlation highlights the statistical interdependence between geomorphometric variables as an artefact of initial data calculation while varying accuracy poses a significant drawback for complex multivariate statistical techniques such as principal component cluster or discriminant analyses

earthquake dammed lakes in new zealand eleven small lakes were formed by landslides caused by the 1929 buller earthquake four others were formed by other historic earthquakes in new zealand at least nine other new zealand lakes are also dammed by landslides and were probably formed by prehistoric earthquakes when recognized by morphology synchronous age and areal distribution earthquake dammed lakes could provide an estimate of paleoseismicity for the past few hundred or thousand years

sediment budget to assess the geomorphic effect of a cyclonic storm new zealand abstract a short term sediment budget was constructed to assess the erosion response of a soft rock hill country watershed to an intense rainstorm event the watershed is located in a landslide prone area on the east coast of the north island new zealand during march 1988 753 mm of rain was recorded over a four day period with 320 mm and 329 mm on successive days known as cyclone bola this was the largest rainstorm event in the tutira watershed in the 93 year rainfall record the budget quantifies the total sediment generated during the storm the relative contribution of erosion processes involved the amount of sediment held in storage and the amount discharged into two lakes within the watershed a landform map of the watershed was constructed and the contribution of each landform type to the total budget was calculated a total of 1 35 0 13 million m3 of sediment was generated during the storm at an average of 420 m3 ha this is equivalent to a denudation value of 42 mm for the total watershed 3208 ha and 83 mm for the landforms severely affected by landsliding 1427 ha of the sediment generated 21 remained on hillslopes 22 was deposited on valley floors 51 was deposited on the lakebeds and the remaining 6 was discharged from the watershed via the lake outlet most of the sediment generated during the storm was from primary source areas on hill slopes with sediment in secondary storage providing only a small contribution landslide erosion was the main process accounting for 89 of the sediment generated channel tunnel gully and sheet erosion were only minor contributors to the budget six hillslope landforms which occupy only 44 of the watershed generated 90 of the sediment the results of this sediment budget when put in context with the storm magnitude frequency history being analysed from lake cores contribute to the identification of sustainable land use and management of soft rock hill country

the formation and impact of landslide dams state of the art abstract the blocking of river courses by mass movements is very common in mountainous areas with deep and narrow valleys landslide dams may pose serious threats to people and their livelihoods downstream in the case of abrupt dam failure since the publication of benchmark reviews of costa and schuster 1988 and korup 2002 there is a growing number of studies focusing on the formation stability and short term impacts of landslide dams this review combines the insights of all these studies builds on current concepts of landslide dams and suggests ways to unify terminologies and classifications we furthermore present a new worldwide database compiled from literature data it contains 410 landslide dams 1 million m3 in volume that were formed since 1900 since these have the most complete data entries these data show that dam longevity is among other factors correlated with the type of landslide forming the dam those formed by rock debris avalanches and rockslides have longest lifespans however the influence of landslide type or material on dam longevity decreases with time after dam formation to ensure consistency in the next database generation we suggest guidelines for data collection to provide a solid basis for evaluating dam stability and governing factors a preliminary classification matrix for landslide dam stability that combines topographic setting and the internal structure of the dam body is another outcome of our review furthermore an evaluation of the various geomorphic stability indices proposed in the literature regarding their suitability and limitations in assessing dam formation and stability shows that they predict the probability of dam formation reasonably well but that their application to longevity estimates requires further assessment the geomorphic impacts of landslide dams in the short medium and long term are summarized and illustrated with key examples finally for a better understanding of the factors controlling dam stability we recommend to 1 include dam composition and sedimentary structures in future case studies 2 maintain and update the worldwide database for sound statistical analyses 3 refine landslide dam stability indices and test them for different landslide types and 4 study hazard cascades related to multiple dams in one watershed for long term landscape evolution studies we suggest to 5 quantify terrestrial sediment flux related to landslide dams 6 detect ancient landslide dams in river profiles and 7 further exploit the sediment archives in former impoundment areas

seismic signals in coastal dune systems abstract coastal dune ridge systems throughout the world form initially in response to phases of abundant sand supply and yet researchers rarely consider the importance of seismic related activity to dune formation or destruction new zealand examples of seismic related coastal dune formation and their occasional remobilisation are discussed pulses of sand sized sediment produced by large earthquakes and transported to the coast by geomorphic processes can generate new dune ridges tsunami inundation can modify existing dunes producing features such as relict dune pedestals landward sand sheets hummocky topography and parabolic dunes the case is put forward for the need to consider evidence for catastrophic events in coastal dune systems particularly when working in tectonically active areas of the world recognition of some of the effects of seismic related processes on coastal dunes however does not mean that these are easily identified in the field or even present in the existing landscape it does however mean that they should not be ignored

in situ stress state in the nankai accretionary wedge estimated from borehole wall failures we constrain the orientations and magnitudes of in situ stress tensors using borehole wall failures borehole breakouts and drilling induced tensile fractures detected in four vertical boreholes c0002 c0001 c0004 and c0006 from nw to se drilled in the nankai accretionary wedge the directions of the maximum horizontal principal stress shmax indicated by the azimuths of borehole wall failures are consistent in individual holes but those in c0002 margin parallel shmax are nearly perpendicular to those in all other holes margin normal shmax constrained stress magnitudes in c0001 and c0002 using logged breakout widths combined with empirical rock strength derived from sonic velocity as well as the presence of the drilling induced tensile fractures suggest that the stress state in the shallow portion of the wedge fore arc basin and slope sediment formations is predominantly in favor of normal faulting and that the stress state in the deeper accretionary prism is in favor of probable strike slip faulting or possible reverse faulting thus the stress regime appears to be divided with depth by the major geological boundaries such as unconformities or thrust faults the margin perpendicular tectonic stress components in the two adjacent sites c0001 and c0002 are different suggesting that tectonic force driven by the plate pushing of the philippine sea plate does not uniformly propagate rather the stress field is inferred to be influenced by additional factors such as local deformation caused by gravitation driven extension in the fore arc and thrusting and bending within individual geologic domains

a massive sensitive clay landslide quyon valley southwestern quebec canada and evidence for a paleoearthquake triggering mechanism abstract a landslide debris field covering 31 km2 the presence of large sediment blocks up to hundreds of meters long and the exposure of deposits of a single landslide along the incised course of the quyon river are evidence of a massive failure of sensitive champlain sea glaciomarine sediments along the lower quyon valley southwestern quebec canada seventeen radiocarbon ages indicate that the failure occurred between 980 and 1060 cal yr bp twenty four additional radiocarbon ages reveal that nine landslides within a 65 km belt in the quyon ottawa area also occurred at approximately this time in combination the contemporaneous occurrence of ten landslides between 980 and 1060 cal yr bp the setting or morphology of five of the other failures and the close proximity of two of the failures to the quyon valley landslide provide circumstantial evidence of a paleoearthquake triggering mechanism the paleoearthquake is estimated to be mw 6 1 or larger with the epicenter within the west quebec seismic zone a common earthquake triggering mechanism for the three largest landslides in eastern canada suggests a close link between massive failures of sensitive glaciomarine sediments and the regional seismicity

quaternary rock uplift rates and their implications for the western flank of the north anatolian fault restraining bend inferences from fluvial terrace ages

palaeoclimatic implications of a storm erosion record from late holocene lake sediments north island new zealand abstract a ca 2250 year storm history has been identified from a high resolution lake sediment record from the east coast of the north island new zealand this event based chronology identifies 340 storms in the pre european record the record is largely one of natural variability without human impacts layers of minerogenic sediment representing the products of individual storm events are clearly visible in lake cores these storm sediment pulses derived mainly from landslides record the frequency and magnitude of storms clusters of pulses identify six periods of high sedimentation and associated erosion before european settlement a d 1878 at least five of these are interpreted as periods of higher rainfall and probably warmer temperatures since historic records show that most large storms are derived from the subtropics tropics most of the storm periods correspond to warm climate intervals previously identified from new zealand and from southern hemisphere palaeoclimatic evidence the mapara 2 period ca 2090 1855 cal yr b p was the stormiest other periods were of shorter duration the mapara 2 period occurred at times of sustained warmth in the tasmanian and chilean tree ring records which might suggest hemispheric warming at this time one storm period burrell which occurred during the historical enso record was at a time of moderately high enso activity three earlier periods also appear to show responses to enso two storm periods correspond to previously proposed new zealand wide periods of increased erosion and sedimentation estimates of palaeo storm rainfalls from relationships between storm rainfall and sediment thickness of historical events suggest that storm pulses ca 12 mm thick represent palaeo storms of ca 450 mm rainfall

evidence of high sea level during isotope stage 5c in queensland australia abstract thirty nine species of scleractinian corals have been recovered from under a high dune on the western mainland side of north stradbroke island eastern australia the corals are associated with thin intertidal sediments and their good condition implies burial in situ and preservation in a saturated zone most likely this occurred as the coast prograded and a large dune advanced into the littoral zone burying intertidal sediments and coral the species assemblage indicates a sheltered environment but one open to the ocean without wide fluctuations in salinity three species yielded a mean 230 th 234 u age of 105 000 yr b p which is significantly younger than the nearest pleistocene corals at evans head new south wales the corals provide evidence of a sea stand near present sea level during isotope stage 5c which is considerably higher than previously suggested for this period their good condition implies that the overlying parabolic dune is of comparable age and formed during that high stand of sea level also the isotope age provides a maximum period for the development of giant podzols in the podzol chronosequences on coastal dunes in southern queensland

prehistorical earthquakes on the alpine fault new zealand studies of synchronous prehistorical landslides in rugged plate boundary mountain ranges can be used to estimate times of earthquakes to locate the earthquake generating fault zones and to describe patterns of seismic shaking lichenometry can date regional rockfall events caused by large earthquakes in the southern alps of new zealand with a 95 confidence level precision of 10 years spatial variation of rockfall abundance an index of seismic shaking is a function of the intensity and duration of seismic shaking and hillslope sensitivity to earthquakes four of the earthquakes of the past 1000 years appear to have caused exceptionally widespread regional rockfall events that were largest opposite the 350 km long cook segment of the alpine fault lichenometric age estimates 10 years of these cook segment earthquakes at 1748 1489 1226 and 967 a d are supported by radiocarbon and weathering rind age estimates of times of coseismic geomorphic processes and by times of prehistorical forest disturbance events a mean earthquake recurrence interval of 260 years 15 years and similar patterns of seismic shaking imply constant rupture length and slip per event in accord with the characteristic earthquake model

a review of age determinations on pleistocene corals in eastern australia abstract samples of corals from all three previously reported pleistocene localities in eastern australia have been dated anew using the 230 th 234 u technique results for two sites are confirmed but the new results for the third site are older than previously reported and do not support a high sea level for isotope substage 5c all sites are now referred to substage 5e

sea level history 45 000 to 30 000 yr b p inferred from benthic foraminifera gulf st vincent south australia surficial sediments of gulf st vincent south australia are predominantly bioclastic cool temperate carbonates benthic foraminifera are abundant and distribution of species is closely related to water depth for example massilina milletti is most common at depths ca 40 m while discorbis dimidiatus is characteristics of shallow subtidal environments elphidium crispum a shallow water species and e macelliforme favoring deeper water provide a useful numerical ratio their logarithmic relative abundance in the sediment size fraction 0 50 0 25 mm correlates strongly with water depth vibrocores sv 4 and sv 5 recovered undisturbed sections of quaternary strata from the deepest part ca 40 m of gulf st vincent amino acid racemization and radiocarbon age determinations show that late pleistocene sections of the cores were deposited over the time ca 45 000 to 30 000 yr b p species of fossil foraminifera recovered from these sections are mostly extant in modern gulf st vincent thus allowing paleoecological inferences of late pleistocene sea levels these inferred sea level maxima can be correlated with those determined from study of huon peninsula coral reef terraces initial estimates of tectonically corrected sea levels for transgressions in gulf st vincent at 40 000 and 31 000 yr b p are 22 5 m and 22 m respectively the intervening regression lowered sea level to 28 m

coseismic landsliding estimates for an alpine fault earthquake and the consequences for erosion of the southern alps new zealand landsliding resulting from large earthquakes in mountainous terrain presents a substantial hazard and plays an important role in the evolution of mountain ranges however estimating the scale and effect of landsliding from an individual earthquake prior to its occurrence is difficult this study presents first order estimates of the scale and effects of coseismic landsliding resulting from a plate boundary earthquake in the south island of new zealand we model an mw 8 0 earthquake on the alpine fault which has produced large m 7 8 8 2 earthquakes every 329 68 years over the last 8 ka with the last earthquake 300 years ago we suggest that such an earthquake could produce 50 000 20 000 landslides at average densities of 2 9 landslides km 2 in the area of most intense landsliding between 50 and 90 are expected to occur in a 7000 km2 zone between the fault and the main divide of the southern alps total landslide volume is estimated to be 0 81 0 87 0 55 km3 in major northern and southern river catchments total landslide volume is equivalent to up to a century of present day aseismic denudation measured from suspended sediment yields this suggests that earthquakes occurring at century timescales are a major driver of erosion in these regions in the central southern alps coseismic denudation is equivalent to less than a decade of aseismic denudation suggesting precipitation and uplift dominate denudation processes nevertheless the estimated scale of coseismic landsliding is considered to be a substantial hazard throughout the entire southern alps and is likely to present a substantial issue for post earthquake response and recovery

osl dating of landslide dammed lake deposits in the north of tehran iran 958 ray taleghan ruyan earthquake abstract one large landslide soleghan in the north of the megacity tehran has been surveyed for dating with osl methods landslide dammed lake deposits of the soleghan landslide was used to obtain the age of the landslide event using the sar protocol for both quartz and feldspar grains the age of the event was 1 09 0 09 ka for quartz and 1 03 0 08 ka and 1 10 0 13 ka for feldspars stimulation at 50 c and 225 c respectively these results suggest that the soleghan mass movement was an earthquake induced landslide triggered by the 23rd february 958 7 7 m ray taleghan ruyan earthquake based on this work thorough review studies of landslides using osl dating methods can be used to determine the age of other mass movements in iran multiple landslides with identical ages which may be attributed to a seismic event could be created by a known earthquake or an unknown earthquake subsequently finding an unknown earthquake will complete the earthquake catalogue resulting in a better hazard assessment

green lake landslide and other giant and very large postglacial landslides in fiordland new zealand abstract green lake landslide is an ancient giant rock slide in gneiss and granodiorite located in the deeply glaciated fiordland region of new zealand the landslide covers an area of 45 km 2 and has a volume of about 27 km 3 it is believed to be new zealand s largest landslide and possibly the largest landslide of its type on earth it is one of 39 known very large 10 6 10 7 m 3 and giant 10 8 m 3 postglacial landslides in fiordland discussed in the paper green lake landslide resulted in the collapse of a 9 km segment of the southern hunter mountains slide debris moved up to 2 5 km laterally and 700 m vertically and formed a landslide dam about 800 m high impounding a lake about 11 km long that was eventually infilled with sediments geomorphic evidence supported by radiocarbon dating indicates that green lake landslide probably occurred 12 000 13 000 years ago near the end of the last otira glaciation the landslide is described and its geomorphic significance age failure mechanism cause and relevance in the region are discussed in relation to other large landslides and recent earthquake induced landslides in fiordland the slope failure occurred on a low angle fault zone undercut by glacial erosion and was probably triggered by strong shaking mm ix x associated with a large m 7 5 8 earthquake on the alpine fault c 80 km to the northwest geology was a major factor that controlled the style and size of green lake landslide and in that respect it is significantly different from most other gigantic landslides future large earthquakes on the alpine fault in fiordland are likely to trigger more very large and giant landslides across the region causing ground damage and devastation on a scale that has not occurred during the last 160 years with potentially disastrous effects on towns tourist centres roads and infrastructure the probability of such an event occurring within the next 50 years may be as high as 45

the application of a matsuoka nakai lade duncan failure criterion to two porous sandstones abstract we summarize two suites of recent true triaxial tests in two porous sandstones coconino and bentheim one suite of tests conducted under constant 2 and 3 which revealed the effect of 2 and 3 on rock failure the other suite of tests performed under constant lode angle determined the failure dependencies on mean stress and lode angle building and modifying failure descriptions by matsuoka nakai mn and lade duncan ld an explicit failure criterion modified mnld that generalizes a class of failure forms is used to fit the novel loading path data of both sandstones the determined failure descriptions fit both rocks well over a wide range of failure conditions then the generated failure descriptions were further used to predict failure conditions under the constant 2 and 3 loading path the predictions by the modified mnld are generally consistent with these data the predictions also successfully replicated the variation of 1 peak with 2 under constant 3 suggesting the potential of the modified mnld to clarify the effect of 2 on rock failure

paleoseismicity and geodynamics in sweden abstract paleoseismicity denotes past pre instrumental earthquakes as recorded by bedrock structures morphological features and sedimentological criteria glacial varves eskers and deltas are excellent records of paleoseismic events data from sweden are presented faults fractures and various types of sedimentary disturbances of late pleistocene and holocene age frequently occur it is concluded that the seismic activity was very intensive in connection with the peak rates of glacial isostatic uplift and that this was a natural effect of the geodynamic processes operating

a comparison of historical and paleoseismicity in a newly formed fault zone and a mature fault zone north canterbury new zealand the timing of large holocene prehistoric earthquakes is determined by dated surface ruptures and landslides at the edge of the australia pacific plate boundary zone in north canterbury new zealand collectively these data indicate two large m 7 earthquakes during the last circa 2500 years within a newly formed zone of hybrid strike slip and thrust faulting herein described as the porter s pass to amberley fault zone ppafz two earlier events during the holocene are also recognized but the data prior to 2500 years are presumed to be incomplete a return period of 1300 2000 years between large earthquakes in the ppafz is consistent with a late holocene slip rate of 3 4 mm yr if each displacement is in the range 4 8 m historical seismicity in the ppafz is characterized by frequent small and moderate magnitude earthquakes and a seismicity rate that is identical to a region surrounding the structurally mature hope fault of the marlborough fault system farther north this is despite an order of magnitude difference in slip rate between the respective fault zones and considerable differences in the recurrence rate of large earthquakes the magnitude frequency distribution in the hope fault region is in accord with the characteristic earthquake model whereas the rate of large earthquakes in the ppafz is approximated but over predicted by the gutenberg richter model the comparison of these two fault zones demonstrates the importance of the structural maturity of the fault zone in relation to seismicity rates inferred from recent historical and paleoseismic data

an earth systems approach to understanding the tectonic and cultural landscapes of linked marine embayments avon heathcote estuary ihutai and lake ellesmere waihora new zealand an earth systems study of the avon heathcote estuary ihutai new zealand shows that tectonic activity has a marked direct and indirect control upon its geomorphology and human settlement in the area we discuss the late holocene history of the embayment in relation to large earthquakes and their after effects of particular note is the rapid fluvial transfer of sand to the coast causing dune formation and a more delayed pulse of coarser sediment causing channel avulsion of the waimakariri river while dune system development seems to occur soon after tectonic activity river channel avulsion spit barrier formation and ongoing geomorphological changes may well relate to periods of tectonic activity that occurred 100 200 years previously the interaction between these two sediment delivery systems causes significant and often rapid changes to coastal geomorphology and ecosystems that have serious implications for human populations living at or near the coast we show a more region wide picture of the direct and indirect effects of tectonic activity by comparing two embayments that represent coastal points of entry at opposite ends of the waimakariri river floodplain the avon heathcote estuary ihutai and lake ellesmere waihora copyright 2005 john wiley sons ltd

climate and tectonic effects on holocene development of an alpine lake muge co se margin of tibet south west china is an important area for determining variability of the sw asian monsoon it is however also tectonically very active palaeolimnological studies in this region generally focus on climate as a direct driver of ecological change rarely considering the effects of tectonic activity and catchment ontogeny we present diatom and organic matter data from a holocene sediment record from muge co an alpine lake located on an active fault zone in the southeast margin of tibet and explore the possible drivers of ecological change a major change occurred at 9000 cal bp when the diatom assemblage switched from benthic to predominantly planktonic forms and organic matter content decreased rapidly comparison of the holocene diatom record with a regional data set of lake surface sediments using detrended canonical correspondence analysis dcca suggests that this change in diatom development was mainly associated with changing water depth most likely linked to a seismically triggered landslide

geomorphic change implied by regolith slope relationships on steepland hillslopes taranaki new zealand abstract slope angle and regolith depth were measured along profile lines covering a range of hillslopes in several small neighbouring drainage basins in taranaki hill country new zealand slope measurements show a cyclic variation along the length of broadly rectilinear profiles variation in slope on the lower portion of profiles adjacent to stream channels indicates that hillslopes have undergone phases of accelerated downcutting and hillslope rejuvenation a recent phase of increased erosion and hillslope rejuvenation is suggested for hillslopes steeper than 31 by the steep lowerslope and incised stream channel hillslope evolution occurs primarily by parallel retreat of steeper swale sites and slope decline during pauses in the rate of downcutting all slope profiles show a large range in regolith depth mean regolith depth of swale sites is highly correlated with mean profile slope angle mean regolith depth decreases and the frequency of landslides increase with increasing mean profile slope angle microtopographic variation in regolith depth is attributed mainly to vegetation effects recurrent landsliding and in part to bedrock curvature hillslope position and slope angle shallowing of regolith is caused by recurrent landsliding on steep swale sites fluvial erosion at the base of steep profiles and surface erosion on extremely convex spur sites the very shallow soil on the steep lowerslope portion of profiles suggests a phase of soil removal consistent with hillslope rejuvenation average depth of regolith is least at 97 cm and variability greatest on hillslopes with a profile mean exceeding 31 erosion rates are greater on these sites where soil is derived predominantly from underlying tertiary sandstone this is attributed to a greater frequency of landsliding compared to hillslopes with a profile slope less than 31 where a more regular and deeper average regolith of 153 cm infers a longer period of hillslope stability consistent with the high volcanic ash content of soils airfall andesitic volcanic ash deposited throughout the holocene has largely been removed from steeper sites the work demonstrates the need to interpret the frequency and distribution of landslides in context with natural geomorphic changes in order to assess the effect that landuse changes has on erosion rates

catastrophic landslides and their effects on the upper indus streams karakoram himalaya northern pakistan abstract the paper examines the nature and geomorphic influences of deposits from rock avalanches that obstruct rivers most of the 115 rockslide rock avalanche events identified in the karakoram himalaya straddled one or more stream valleys at least 73 of these landslides formerly dammed the indus or its tributaries upstream of the barriers remnants exist of once very extensive lacustrine deposits the stability and long term survival of dams from large rock avalanches is addressed and the reasons for the gradual or phased rather than catastrophic and sudden breaching case histories emphasise the erosional and depositional forms associated with the barriers they are reconstructed in terms of the emplacement and properties of the deposits from rock avalanches and the response of the river to interruption by them these barriers have exerted a substantial control over stream response and development for most of the holocene at least today they are associated with distinctive features of channel form and thalweg river terrace systems intermontane sediment sinks and sources and local erosional forms in bedrock more broadly the landslide barriers have created a naturally fragmented river system deposition and erosion in the lower few tens or hundreds of meters of the upper indus stream valleys have been dominated by epicycles of aggradation trenching and downcutting that mainly reflect the scale timing and history of each barrier the landforms involved are only indirectly related to the late glacial and paraglacial conditions that have hitherto been regarded as the main explanation

active tectonic studies in the united states 1987 1990 the techniques and instrumentation used in active tectonic studies are discussed and recent results are reviewed it is suggested that a critical mass of data on several particular regions has been accumulated making possible critical debates and attempts to assess earthquake hazards particular attention is given to studies of the pacific northwest region basin and range deformation studies and distributed deformation and hidden earthquake sources also included is a comprehensive bibliography for the period

in situ stress conditions at iodp site c0002 reflecting the tectonic evolution of the sedimentary system near the seaward edge of the kumano basin offshore from sw japan this paper presents a complete set of in situ stress calculations for depths of 200 1400 mbsf meters below seafloor at iodp site c0002 near the seaward margin of the kumano forearc basin offshore from southwest japan the vertical stress component was obtained by integrating bulk density calculations from moisture and density logging data and the two horizontal components were stochastically optimized by minimizing misfits between a probabilistic model and measured breakout widths for every 30 m vertical segment of the wellbore our stochastic optimization process reveals that the in situ stress regime is decoupled across an unconformity between an accretionary complex and the overlying kumano forearc basin the stress condition above the unconformity is close to the critical condition for normal faulting while below the unconformity the geologic system is stable in a normal to strike slip fault stress regime the critical state of stress demonstrates that the tectonic evolution of the sedimentary system has been achieved mainly by the regionally continuous action of a major out of sequence thrust fault during sedimentation in the forearc basin the stable stress condition in the accretionary prism is interpreted to have resulted from mechanical decoupling by the accommodation of large displacement along the megasplay fault

insights into subtropical australian aridity from welsby lagoon north stradbroke island over the past 80 000 years abstract terrestrial sedimentary archives that record environmental responses to climate over the last glacial cycle are underrepresented in subtropical australia limited spatial and temporal palaeoenvironmental record coverage across large parts of eastern australia contribute to uncertainty regarding the relationship between long term climate change and palaeoecological turnover including the extinction of australian megafauna during the late pleistocene this study presents a new high resolution calibrated geochemical record and numerical dating framework from welsby lagoon a wetland from north stradbroke island that records key periods of late pleistocene environmental change single grain optically stimulated luminescence and radiocarbon dating are integrated into a bayesian age depth model for the sedimentary sequence spanning marine isotope stage mis 5 to the present scanning micro x ray fluorescence xrf and bulk sediment xrf assays are used to infer past dust dynamics with changes in the abundance of silica and potassium interpreted as proxies for aridity across local and regional sources variations in dust flux were contemporaneous with hydrological change concordant with changes in vegetation cover on the island and relate to deflation events at major dust source regions on the australian continent the welsby lagoon record supports the notion of a variable mis4 within which an increased dust flux 71 67 ka may be indicative of drier climate additionally the record also shows a lower dust flux through the last glacial maximum lgm than is evident in other australian aeolian records however this low lgm flux is attributed to the wetland s evolution rather than a reduction in total dust flux

seismic driving of sand beach ridge formation in northern honshu japan abstract the coastal sendai plain consists of an extensive sand beach ridge system that was inundated by the 2011 tohoku oki tsunami the spatial and temporal extent of these beach ridges appears to match well with the record of past earthquakes and tsunamis in the region and it is proposed that they could have formed as a result of a process called seismic driving this process recognises the widespread and catastrophic disruption of the environment caused by a large earthquake a series of immediate and delayed after effects created by a cascade of geomorphological processes linking the earthquake with beach ridge formation is examined for the sendai plain the significance of the role played by volcanic eruptions smaller earthquakes and climate related high intensity and duration rainfall activity is also highlighted at a region wide scale the beach ridge systems of ishinomaki akita aomori and tanabu are also considered alongside those of the sendai plain throughout northern honshu there appears to be synchronous beach ridge formation albeit based upon a moderately poor chronological resolution further data indicate that there may also be contemporaneous evidence on hokkaido to the north more detailed research is now needed in order to secure a higher resolution dataset of the spatial and temporal extent of beach ridges throughout the region in order to determine whether they preserve a record of the magnitude and frequency of earthquakes and potentially tsunamis related to activity on both the japan and kuril trenches if strong seismic driving linkages can be proven it offers the intriguing possibility of being able to develop a far more comprehensive record of past earthquakes and tsunamis local regional and distant than currently exists records could be based on both tsunami deposits in the low lying swales and the spatial and temporal extent of the intervening beach ridges

post rock avalanche dam outburst flood sedimentation in ram creek southern alps new zealand rock avalanches are common in mountainous regions that are tectonically active they are capable of forming natural dams of uncertain persistence that have significant impacts on the river system over wide spatial scales and possibly over geological time scales here we combine field data and digital elevation model dem analysis to show the response of ram creek new zealand to 28 years of sediment dispersion following the 1968 emplacement of a co seismic rock avalanche dam that breached catastrophically in 1981 the results show a system that has not attained equilibrium being unable to move the quantity of dam derived sediments and will likely not attain equilibrium before the next major sediment input it is in a state of persistent disturbance where localised reworking dominates erosion in ram creek is focussed on lateral bevelling and bedrock gorge widening rather than vertical incision to keep pace with tectonic uplift importantly for studies of tectonic geomorphology this widening which if sustained will form a strath terrace does not represent a period of reduced uplift stream metrics concavity and steepness are unable to differentiate the identified rock avalanche induced knickpoint from tectonic and lithological knickpoints

rock avalanches clusters along the northern chile coastal scarp abstract rock avalanche clusters can be relevant indicators of the evolution of specific regions they can be used to define the type and intensity of triggering events their recurrence and potential probability of occurrence the progressive damage of the rock mass the mechanisms of transport and deposition as well as the environmental conditions at the time of occurrence this paper tackles these subjects by analyzing two main clusters of rock avalanches each event between 0 6 and 30 mm 3 separated by few kilometers and located along the coastal scarp of northern chile south of iquique it lies hence within a seismic area characterized by a long seismic gap that ended on april 1st 2014 with a m w 8 2 earthquake the scar position high along the coastal cliff supports seismic triggering for these clusters the deposits relative positions are used to obtain the sequence of rock avalanching events for each cluster the progressive decrease of volume in the sequence of rock avalanches forming each cluster fits well the theoretical models for successive slope failures these sequences seem to agree with those derived by dating the deposits with ages spanning between 4 kyr and 60 kyr an average uplift rate of 0 2 mm yr in the last 40 kyr is estimated for the coastal plain giving a further constraint to the rock avalanche deposition considering the absence of reworking of the deposits volume estimates and datings allow the estimation of an erosion rate contribution of about 0 098 0 112 mm km 2 yr 1 which is well comparable to values presented in the literature for earthquake induced landslides we have carried out numerical modeling in order to analyze the mobility of the rock avalanches and examine the environmental conditions that controlled the runout in doing so we have considered the sequence of individual rock avalanches within the specific clusters thus including in the models the confining effect caused by the presence of previous deposits bingham rheology was the most successful at explaining both the distance and the geometry of the observed events

36cl production rate from k spallation in the european alps chironico landslide switzerland the abundant production of in situ cosmogenic 36cl from potassium renders 36cl measurements in k rich rocks or minerals such as k feldspars potentially useful for precisely dating rock surfaces either in single nuclide or in multi nuclide studies for example combined with 10be measurements in quartz however significant discrepancies in experimentally calibrated 36cl production rates from spallation of potassium 36pk sp referenced to sea level high latitude slhl limit the accuracy of 36cl dating from k rich lithologies we present a new 36cl calibration using k feldspars in which k spallation is the most dominant 36cl production pathway 92 of total 36cl thus minimizing uncertainties from the complex multi pathway 36cl production systematics the samples are derived from boulders of an 13 4 ka old landslide in the swiss alps 820 m 46 43 n 8 85 e we obtain a local 36pk sp of 306 16 atoms 36cl g k 1 a 1 and an slhl 36pk sp of 145 5 7 7 atoms 36cl g k 1 a 1 when scaled with a standard scaling protocol lm applying this slhl 36pk sp to determine 36cl exposure ages of k feldspars from 10be dated moraine boulders yields excellent agreement confirming the validity of the new slhl 36pk sp for surface exposure studies involving 36cl in k feldspars in the alps