empirical predictive models for earthquake induced sliding displacements of slopes earthquake induced sliding displacement is the parameter most often used to assess the seismic stability of slopes the expected displacement can be predicted as a function of the characteristics of the slope yield acceleration and the ground motion e g peak ground acceleration yet there is significant aleatory variability associated with the displacement prediction using multiple ground motion parameters to characterize the earthquake shaking can significantly reduce the variability in the prediction empirical predictive models for rigid block sliding displacements are developed using displacements calculated from over 2 000 acceleration time histories and four values of yield acceleration these empirical models consider various single ground motion parameters and vectors of ground motion parameters to predict the sliding displacement with the goal of minimizing the standard deviation of the displacement prediction the combination of peak ground acceleration and peak ground velocity is the tw

north west european mis 11 malacological successions a framework for the timing of acheulean settlements apart from a few lacustrine sequences in north west europe the marine isotope stage mis 11 interglacial is mainly represented in fluvial sequences and is particularly well preserved in calcareous tufa formations these are favourable for the preservation of a range of fossil groups and several of them have yielded artefacts of acheulean affinity molluscan shells are the most abundant proxy occurring throughout these calcareous deposits they provide a valuable means for reconstructing the palaeoenvironments contemporaneous with human occupation allowing direct comparisons between sites the la celle tufa northern france provides the longest malacological succession which allows a detailed reconstruction of the development of forest cover successive arrivals of forest species first from an atlantic corridor and later from central and southern european routeways allow characterization of vegetational development the initial immigrants indicate the spread of closed habitats while a peak in the diversity of thermophilous snails corresponds to the optimum phase of deciduous forest expansion a subsequent decrease in forest molluscs together with expansion of hygrophilous species indicates the decline of closed canopy conditions the occurrence of critical forest species especially those now extinct or occurring far beyond their modern ranges provides a framework within which associated acheulean industries can be set

palaeoenvironmental dynamics of the mis 11 interglacial in north western europe based on the malacological succession from la celle seine valley france relationship with glacial refugia and palaeobiodiversity abstract in north western europe continental records of pleistocene interglacials are well preserved in fluvial sequences and particularly within calcareous tufas that formed at the top of the series they are the sole deposits recording the full optima tufas contain rich malacological communities that allow the detailed palaeoenvironmental history of past interglacials to be reconstructed several tufas have been investigated in the study area which have led to the recognition of the lyrodiscus fauna as a characteristic biostratigraphical signature of tufa sequences of mis 11 age in north western europe among these the site at la celle in the seine valley france is the only one where tufa has accumulated a substantial thickness almost 9 m in which the complete development of the lyrodiscus fauna is represented yielding a detailed record of the forest expansion during the mis 11 interglacial the la celle succession therefore provides a regional framework into which other sequences can be set shedding lights on various aspects of palaeoenvironmental dynamics biostratigraphy palaeogeography and palaeobiodiversity combined malacological and isotopic records from la celle demonstrate a close correlation between increasing temperatures and the development of forest land snail communities the palaeoecological framework of forest extension inferred from the malacological succession of la celle allows the shorter successions from northern france and south eastern england to be located within the maximum development of the humid forest biotope during mis 11c the order of occurrence of forest snails indicates that atlantic and central european refugia are the original sources of recolonizations for north western european sites strict mediterranean species reach the area only at the mis 11c climatic optimum many species present during mis 11c no longer live in this part of europe indicating a northward shift in the location of the modern alpine biodiversity hotspot

characteristic landslide distributions an investigation of landscape controls on landslide size abstract estimation of landslide erosion rates and hazard prediction require a firm understanding of the physical controls on landslide size in this study we seek to understand how the characteristics of different landscapes and forcing events influence the distribution of landslide size at a regional scale we explore the parameter space of a mechanically based landslide model through a series of simulations using digital elevation data consistent with previous studies we find that large slope failures are infrequent due to the scarcity of large steep hillslopes in typical mountainous topography on the other hand we find that the occurrence of small landslides is limited by the cohesive strength of hillslope material which overcomes the weaker driving forces on short slopes we test our model results with an empirical investigation of frequency size distributions for eight real co seismic landslide inventories although empirical data are noisy we find a positive correlation between landslide size and hillslope relief while the effects of pga on landslide size are less pronounced we conclude that landslide size distributions reflect the available distribution of hillslope geometries in a given landscape and that external forcing e g seismic ground motion determines which subset of the hillslope distribution fails during a particular event for a given landscape and forcing event there is a particular length scale over which landsliding is statistically favored leading to the concept of characteristic landslide size distributions

the development of terrestrial mollusc faunas in the rheinland region western germany and luxembourg during the lateglacial and holocene abstract a composite faunal history covering the last 13 000 radiocarbon years has been reconstructed from the few molluscan successions available from the rheinland region the region centred on the german land of rheinland pfalz but including the principality of luxembourg does not form a discrete biogeographical province but does represent an important link between the better known faunas of central europe and those of north west europe open ground assemblages dominated by vallonia and trichia with few shade demanding elements occur throughout the lateglacial and early holocene the lateglacial is characterised by the presence of vertigo genesii and abida secale depending on whether the depositional environment is wet or dry respectively catholic elements became increasingly important at the start of the holocene the establishment of woodland from approximately 9700 yr bp is indicated by the expansion of shade demanding taxa most notably carychium tridentatum deciduous forest optimum faunas developed by about 7500 yr bp and are characterised by platyla polita perforatella incarnata and sphyradium doliolum the modern ranges of these species suggest that during the holocene platyla polita perforatella incarnata and possibly sphyradium doliolum also colonised northwestern europe from refugia further east the reappearance of open ground faunas from 5000 yr bp reflects widespread anthropogenic clearance

hydrogeological characterization of an altered wetland summary spatiotemporal changes in the hydrogeology of the hula altered wetland may influence the water quality of lake kinneret which provides up to 30 of the potable water for the state of israel the main objectives of this work were to study the groundwater flow characteristics in this wetland and assess the potential impact on downstream water quality we constructed variograms of hydraulic heads computed decision tree models of major ions and determined the hydraulic conductivity k and 2 h 18 o ratios to ascertain the spatial and vertical distribution of hydrogeological parameters we also performed large scale field experiments 1 km 2 to assess the connectivity between the waterways and the wetland s aquifer the aquifer is fragmented by three parent materials deep peat shallow peat marl complex and marl the decision tree based model the isotopic ratios and k determinations suggest that the deep peat subaquifer is composed of one homogeneous layer characterized by low k 0 001 m d 1 the two other subaquifers consist of three hydrostratigraphic layers i the vadose zone ii a layer with well developed macropores at a depth of 1 5 4 m and iii an aquitard layer at a depth of 4 15 m the temporal head fluctuations the high k values of the second layer 170 m d 1 and the large volume of water flowing into and out of the two subaquifers during large scale field experiments all attest to excellent connectivity with the waterways these results support the concept of critical source area which claims that most of the p loss in a catchment derives from small areas in which specific p release and transport mechanisms coincide with high connectivity we conclude that the high connectivity of this mediterranean altered wetland to waterways coupled with the high p release that has occurred in recent years following soil flooding provides the loading mechanism that partially explains the observed p increase in the jordan river

changes to the environment of intramontane basins in the light of malacological research of calcareous tufa podhale basin carpathians southern poland the profiles of calcareous tufa occurring in the podhale basin carpathians southern poland were subject to a detailed malacological analysis studies were carried out in 15 sites five of them represent the period of the late glacial and holocene and the remainder is tufa deposited during historical times on the basis of malacological analysis 10 faunistic assemblages were defined each developed under specific environmental and climatic conditions the observed sequences of molluscan assemblages in vertical profiles were the basis for paleoenvironmental reconstruction determining the main phases of climatic changes and the human impact on the natural environment the faunal sequence observed indicates a cold climate and the predominance of open habitats in the late glacial with progressing warming and the increasing significance of shaded habitats in the early and middle holocene as well as anthropogenic pressure in modern times the results of malacological analysis were complemented with determination of the age of deposits by radiocarbon dating and the results of palynological analyses conducted in the sites of peatbogs occurring in podhale the reconstruction indicates similarities and differences in the paleogeographic development of mountain and upland areas of central europe

application and evaluation of a rapid response earthquake triggered landslide model to the 25 april 2015 mw 7 8 gorkha earthquake nepal abstract the 25 april 2015 m w 7 8 gorkha earthquake produced strong ground motions across an approximately 250 km by 100 km swath in central nepal to assist disaster response activities we modified an existing earthquake triggered landslide model based on a newmark sliding block analysis to estimate the extent and intensity of landsliding and landslide dam hazard landslide hazard maps were produced using shuttle radar topography mission srtm digital topography peak ground acceleration pga information from the u s geological survey usgs shakemap program and assumptions about the regional rock strength based on end member values from previous studies the instrumental record of seismicity in nepal is poor so pga estimates were based on empirical ground motion prediction equations gmpes constrained by teleseismic data and felt reports we demonstrate a non linear dependence of modeled landsliding on aggregate rock strength where the number of landslides decreases exponentially with increasing rock strength model estimates are less sensitive to pga at steep slopes 60 compared to moderate slopes 30 60 we compare forward model results to an inventory of landslides triggered by the gorkha earthquake we show that moderate rock strength inputs over estimate landsliding in regions beyond the main slip patch which may in part be related to poorly constrained pga estimates for this event at far distances from the source area directly above the main slip patch however the moderate strength model accurately estimates the total number of landslides within the resolution of the model landslides 0 0162 km 2 observed n 2214 modeled n 2987 but the pattern of landsliding differs from observations this discrepancy is likely due to the unaccounted for effects of variable material strength and local topographic amplification of strong ground motion as well as other simplifying assumptions about source characteristics and their relationship to landsliding

earthquake induced chains of geologic hazards patterns mechanisms and impacts large earthquakes initiate chains of surface processes that last much longer than the brief moments of strong shaking most moderate and large magnitude earthquakes trigger landslides ranging from small failures in the soil cover to massive devastating rock avalanches some landslides dam rivers and impound lakes which can collapse days to centuries later and flood mountain valleys for hundreds of kilometers downstream landslide deposits on slopes can remobilize during heavy rainfall and evolve into debris flows cracks and fractures can form and widen on mountain crests and flanks promoting increased frequency of landslides that lasts for decades more gradual impacts involve the flushing of excess debris downstream by rivers which can generate bank erosion and floodplain accretion as well as channel avulsions that affect flooding frequency settlements ecosystems and infrastructure ultimately earthquake sequences and their geomorphic consequences alter mountain landscapes over both human and geologic time scales two recent events have attracted intense research into earthquake induced landslides and their consequences the magnitude m 7 6 chi chi taiwan earthquake of 1999 and the m 7 9 wenchuan china earthquake of 2008 using data and insights from these and several other earthquakes we analyze how such events initiate processes that change mountain landscapes highlight research gaps and suggest pathways toward a more complete understanding of the seismic effects on the earth s surface

holocene succession patterns of land snails across temperate europe east to west variation related to glacial refugia climate and human impact abstract although holocene mollusc succession has been described from many temperate european sites no attempt to analyse diversity patterns across the continent from east to west has yet been done here we assembled and quantitatively analysed 54 most representative holocene successions categorized into five climatic and geomorphological regions these were defined along a longitudinal transect across temperate europe i e west carpathians bohemian massif west continental atlantic france and atlantic england we found a clear east west gradient in the holocene dynamic of land snail assemblages correlating mainly with the changes in strictly forest species richness representation of these species increased towards the east in accordance with known position of glacial refugia in the carpathian mountains the west carpathians acted as a unique refugium expressing the highest temporal stability of holocene snail assemblages with a sharp increase in strictly forest species richness already in the early holocene in contrast atlantic regions characterized by low elevation and low topographical heterogeneity were always poor in number of strictly forest species with no or only shallow increase of their richness in the holocene climatic optimum further reduction in the second half of the holocene along with the increase of strictly open country species richness correlates with higher human impact on mollusc faunas in lowland and flat regions these factors can explain the previously reported impoverishment of modern western european forest fauna and have apparently also contributed to regional diversity patterns throughout the holocene among the regions we found three types of successional trajectories in the composition changes of holocene molluscs mirroring the above mentioned east west gradient with the west carpathians having the most distinctive fauna our results show that distance from glacial refugia landscape topography and also human impact importantly shaped the species richness dynamic and successional pathways of holocene land snail fauna across temperate europe

a one step newmark displacement model for probabilistic seismic slope displacement hazard analysis abstract estimating the earthquake induced sliding displacement is important in assessing the stability of slopes during earthquakes current newmark displacement models generally use ground motion intensity measures ims as predictors and the uncertainties of predicting im values need to be accounted for in probabilistic seismic slope displacement hazard analysis this paper aims at developing a simple one step predictive model for the newmark displacement based on only four seismological parameters moment magnitude rupture distance fault categories and shear wave velocity at top 30 m vs30 rather than any ims the predictive model is suitable for critical acceleration from 0 02 g to 0 25 g covering most of the susceptible earthquake induced landslide cases first the proposed one step model is compared with some recently developed im based newmark displacement models it is found that both the median predictions and the variabilities of the proposed one step model are in reasonable agreement with those obtained by the im based models second several hypothetical slopes are used to compare the slope displacement hazard curves between the one step model and the im based models the new model can be used as an alternative method for a fully probabilistic analysis of the earthquake induced slope displacements in addition spatial correlations of the newmark displacement residuals are also investigated using strong motion data from the northridge and chi chi earthquakes

holocene succession and biogeographical importance of mollusc fauna in the western sudetes czech republic abstract the location of the sudetes mts between the alpine and scandinavian ice sheets during the quaternary period makes this area interesting from a biogeographic point of view little information was known about the holocene mollusc and vertebrate fauna of this area up to now despite some regional differences among particular mountain areas it seems that sudetes holocene mollusc succession follows a similar but moderate course to that of the standard central european holocene succession the starkov vapenka sequence can be used as a standard succession pattern for this area some woodland species can survive the glacial in talus slope debris with suitable microhabitats e g oxychilus depressus the structure of the vertebrate assemblage suggests that the valleys of krkonose mts might provide favourable conditions for a diversified mammalian community and could take the role of a glacial refugee this study indicates that isolated occurrences of alpine and carpathian elements such as cochlodina dubiosa corcontica endemic in krkonose mts are not relics of a former much wider distribution but modern immigrants of the younger half of the holocene and thus its spreading was very slow it seems that the western sudetes mts except for the jest d ridge were an island of low mollusc diversity not human induced but natural during the whole holocene

holocene palaeoenvironments from the direndall tufa luxembourg reconstructed from the molluscan succession and stable isotope records this paper reports the results of new malacological analyses from a thick tufa sequence at direndall luxembourg the study is temporally contextualised with radiocarbon dates and an age depth mod

seismically induced rock slope failures resulting from topographic amplification of strong ground motions the case of pacoima canyon california abstract the 1994 northridge earthquake mw 6 7 triggered extensive rock slope failures in pacoima canyon immediately north of los angeles california pacoima canyon is a narrow and steep canyon incised in gneissic and granitic rocks peak accelerations of nearly 1 6 g were recorded at a ridge that forms the left abutment of pacoima dam peak accelerations at the bottom of the canyon were less than 0 5 g suggesting the occurrence of topographic amplification topographic effects have been previously suggested to explain similarly high ground motions at the site during the 1971 mw 6 7 san fernando earthquake furthermore high landslide concentrations observed in the area have been attributed to unusually strong ground motions rather than higher susceptibility to sliding compared with nearby zones we conducted field investigations and slope stability back analyses to confirm the impact of topographic amplification on the triggering of landslides during the 1994 earthquake our results suggest that the observed extensive rock sliding and falling would have not been possible under unamplified seismic conditions which would have generated a significantly lower number of areas affected by landslides in contrast modelling slope stability using amplified ground shaking predicts slope failure distributions matching what occurred in 1994 this observation confirms a significant role for topographic amplification on the triggering of landslides at the site and emphasises the need to select carefully the inputs for seismic slope stability analyses

a seismologically consistent expression for the total area and volume of earthquake triggered landsliding we present a new seismologically consistent expression for the total area and volume of populations of earthquake triggered landslides this model builds on a set of scaling relationships between key parameters such as landslide spatial density seismic ground acceleration fault length earthquake source depth and seismic moment to assess the model we have assembled and normalized a catalog of landslide inventories for 40 shallow continental earthquakes low landscape steepness causes systematic overprediction of the total area and volume of landslides when this effect is accounted for the model predicts the total landslide volume of 63 of 40 cases to within a factor 2 of the volume estimated from observations r2 0 76 the prediction of total landslide area is also sensitive to the landscape steepness but less so than the total volume and it appears to be sensitive to controls on the landslide size frequency distribution and possibly the shaking duration some outliers are likely associated with exceptionally strong rock mass in the epicentral area while others may be related to seismic source complexities ignored by the model however the close match between prediction and estimate for about two thirds of cases in our database suggests that rock mass strength is similar in many cases and that our simple seismic model is often adequate despite the variety of lithologies and tectonic settings covered this makes our expression suitable for integration into landscape evolution models and application to the anticipation or rapid assessment of secondary hazards associated with earthquakes

landslides triggered by the 1994 northridge california earthquake abstract the 17 january 1994 northridge california earthquake m w 6 7 triggered more than 11 000 landslides over an area of about 10 000 km 2 most of the landslides were concentrated in a 1000 km 2 area that included the santa susana mountains and the mountains north of the santa clara river valley we mapped landslides triggered by the earthquake in the field and from 1 60 000 nominal scale aerial photography provided by the u s air force and taken the morning of the earthquake these mapped landslides were subsequently digitized and plotted in a gis based format most of the triggered landslides were shallow 1 to 5 m thick highly disrupted falls and slides within weakly cemented tertiary to pleistocene clastic sediment average volumes of these types of landslides were less than 1000 m 3 but many had volumes exceeding 100 000 m 3 the larger disrupted slides commonly had runout paths of more than 50 m and a few traveled as far as 200 m from the bases of steep parent slopes deeper 5 m thick rotational slumps and block slides numbered in the tens to perhaps hundreds a few of which exceeded 100 000 m 3 in volume most of these were reactivations of previously existing landslides the largest single landslide triggered by the earthquake was a rotational slump block slide having a volume of 8 10 6 m 3 analysis of the mapped landslide distribution with respect to variations in 1 landslide susceptibility and 2 strong shaking recorded by hundreds of instruments will form the basis of a seismic landslide hazard analysis of the los angeles area

human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use schot p p and van der wal j 1992 human impact on regional groundwater composition through intervention in natural flow patterns and changes in land use j hydrol 134 297 313 the relations between groundwater composition land use soil conditions and flow patterns on a regional scale are studied for the gooi and vechtstreek area in the netherlands this densely populated area consists of a glacier created ridge with dry sand soils bordered by the vecht and eem river plains with wet peat and clay soils r mode factor analysis and q mode cluster analysis were applied to a set of 1349 groundwater analyses to determine the factors controlling groundwater composition and the main resulting water types the results indicate that groundwater composition in the study area is affected on a regional scale by human activities through changes in land use and intervention in natural flow patterns on the ridge ground water is recharged by precipitation which dissolves carbonates from the matrix of the sandy aquifer increased solute concentrations in shallow ground water especially of nitrate sulphate and potassium indicate increased pollution resulting from urbanization and increasingly intensive agricultural activity over the past decades in the vecht river plain infiltration occurs as a result of drainage of polders and groundwater extraction on the ridge recharge occurs by precipitation and from polluted surface water to which ammonium organic complexes and carbonic acid are added through decomposition of organic matter in the peat and clay soils the carbonic acid results in enhanced dissolution of carbonates present in the soil and the underlying sandy aquifer oxygen depletion and subsequent low redox potentials result in denitrification dissolution of manganese and iron oxides and sulphate ro duction the flow of ground water from high level to low level polders causes displacement of a former stagnant brackish groundwater body under the vecht river plain accompanied by increased mixing of fresh and brackish ground water

the influence of dem resolution on seismic landslide hazard assessment based upon the newmark displacement method a case study in the loess area of tianshui china the estimation uncertainties and spatial variability of input parameters are gaining more attention and have frequently been taken into account in seismic slope deformation predictions but the influence of dem resolution has rarely been investigated in this paper the impact of dem resolution on the seismic landslide hazard is investigated through the comparison between various seismic landslide hazard assessments evaluated from multi resolution 10 30 and 90 m dems in the loess area of tianshui china using the newmark displacement method the results show that the 90 m relatively coarse resolution dem underestimates the estimated newmark displacement the 30 and 10 m resolution dems basically give the similar predictions while the 10 m higher resolution gives higher resolution at the local convex topography such as scarps and ridge crests it suggests that the ability of newmark method to predict landslide occurrence accurately not only depends on the assigned shear strengths but also is controlled predominantly by the distribution of slope angles making accurate maps of seismic landslide hazards will require high resolution dem apart from the associated ground motion parameters and assigned shear strengths

effects of directionality and vertical component of ground motions on seismic slope displacements in newmark sliding block analysis abstract the newmark sliding block model is widely used in the evaluation of seismic slope stability when using this model the horizontal acceleration is usually considered to act parallel to the slope downslope and the vertical component of ground motions is commonly ignored this study investigates the effect of vertical accelerations on the results of sliding displacement and quantitatively compares the difference of the displacement dn calculated from the original newmark s approach with the displacement dhv calculated from a more realistic case horizontal and vertical accelerations properly considered for this purpose 4136 ground motion recordings are selected from the nga west2 database and 2000 hypothetic slopes are simulated with critical accelerations ac ranging from 0 to 0 8 g comparison of dhv and dh shows that the incorporation of vertical accelerations only slightly increases the displacement besides the calculated dhv dn ratios are generally in the range of 1 to 5 indicating that dn significantly underestimates the slope displacement due to the simplification of seismic excitations the dhv dn ratios generally increase as ac increases simple predictive models are proposed to quantify the correction factor kd kd dhv dn they can be easily used in seismic landslide hazard assessment to improve the performance of the original newmark s approach

the late quaternary environmental history of batorliget n e hungary abstract a sedimentary sequence extending back into the last glacial has been obtained from batorliget marsh in n e hungary reconstruction of the environmental history of the region using the techniques of pollen analysis molluscan analysis and geochemistry has revealed an important late quaternary refugium during the last glacial a refugium for temperate flora and fauna existed within a landscape dominated by coniferous forest predominantly made up of pinus and picea the lateglacial postglacial transition at 10 000 yr b p resulted in a dramatic shift from coniferous but also including betula woodland to deciduous woodland following the lateglacial postglacial transition a highly diverse woodland became established in the early postglacial accompanied by an equally diverse molluscan assemblage this diversity remained throughout the early postglacial although the types present within the woodland changed a number of times at c 7000 yr b p anthropogenic disturbance resulted in the destruction of the mixed forest and the development of agricultural land the importance of this region as a refugial area both in the lateglacial and early postglacial is discussed and the influence that it had on the postglacial development of the fauna and flora of northeastern hungary is reviewed

the application of predictive modeling techniques to landslides induced by earthquakes the case study of the 26 september 1997 umbria marche earthquake italy abstract during september and october 1997 an earthquake sequence of moderate magnitude struck the umbria and marche regions central italy as a consequence of the most severe shocks several landslides were triggered on bedrock calcareous debris and sandy clay deposits the landslide inventory collected in the field and by aerial photo interpretation provided an opportunity to test the accuracy of existing predictive relations for landslide hazard zoning and to formulate new ones shallow soil slides and debris slides were selected to verify the prediction performance of the methods which are based on a simplified model geotechnique 15 1965 139 that calculate landslide displacements during cyclic seismic loading rock falls were modeled using a different approach to produce an empirical predictive rule for determining the probability of detachment of blocks when landslides occur along pre existing or newly formed failure surfaces the arias intensity and destructiveness potential are the strong ground motion parameters that best relate to displacements the predictive relation proposed for rock falls evaluates the probability of occurrence as a function of the slope angle and the peak ground acceleration pga

molluscan successions from the holocene tufa of st germain le vasson normandy france and their biogeographical significance a detailed molluscan succession from a 10 m thick deposit of holocene tufa at st germain le vasson normandy provides the most complete record from northern france and has shed new light on the historical biogeography of several species of land snail the succession has been reconstructed from four profiles and a chronology provided by accelerator mass spectrometry radiocarbon dating of charcoal wood and shell the onset of tufa formation occurred after 9700 90 yr bp and persisted until 4213 77 yr bp the tufa appears to have accumulated at a remarkably constant rate 14 4 16 5 cm 100 yr 1 except for the upper levels where the rate increases fourfold the succession has been divided into six local molluscan zones an early assemblage consisting of ecologically tolerant species and those indicative of marshy grassland is replaced by a sequence of shade demanding taxa reflecting the encroachment of woodland shaded conditions persist until the end of the sequence but the most hygrophilous elements decline after 5422 60 yr bp zone 5 a change also reflected in the tufa lithology by the development of silty grey horizons notable species recovered from the tufa include acicula fusca vertigo substriata v alpestris v moulinsiana all rare or unknown living in northern france hygromia limbata a twentieth century introduction to britain was previously thought to be a relatively recent arrival in northern france but its record at st germain shows that it has been present in normandy since 6500 yr bp azeca goodalli another shade demanding species appeared at st germain much later just after 4420 65 yr bp several other species present in the tufa such as pomatias elegans no longer live on the site adding to the evidence for a distributional decline in normandy and elsewhere perhaps the most noteworthy record is that of leiostyla anglica between about 8500 yr bp and 5000 yr bp because this constitutes its only holocene occurrence from mainland europe following this discovery it seems likely that further holocene sites with l anglica may be found along the western seaboard of europe connecting populations in iberia with those of the british isles copyright 2004 john wiley sons ltd

seismically induced mass movements and volumetric fluxes resulting from the 2010 mw 7 2 earthquake in the sierra cucapah mexico the observation that sediment flux from mountain ranges struck by high magnitude earthquakes can be strongly influenced by coseismic mass movements brings into question the nature of coseismic deformation as a net contributor to mountain building to better constrain the role of high magnitude earthquakes in orogenesis high resolution data of earthquake induced mass wasting is required for areas of differing tectonic morphological and climatic settings here we compare the erosional flux to the tectonic flux associated with the 2010 mw 7 2 sierra el mayor earthquake in mexico and examine the landslide patterning of coseismic mass movements associated with this event the ruptured fault system has a significant strike slip component with subsidence along the eastern flank and uplift on the western flank of the range peak ground acceleration was highest along the steepest sections of the range such that the frequency of landslide occurrence was strongly correlated to slope gradient both vertical and horizontal coseismic displacement demonstrated a strong control over landslide initiation this result suggests that strike slip systems experience very different landslide patterning to thrust faults during earthquakes based on interferometric analysis of synthetic aperture radar images the earthquake resulted in a total uplifted volume of 41 6 106 m3 and a loss of 95 2 106 m3 due to subsidence this suggests a net tectonic volumetric flux of 53 6 106 m3 sediment mobilisation by coseismic landslides is estimated at 2 7 106 m3 derived from a manually mapped inventory using spot 5 multispectral imagery thus the net volume loss through coseismic subsidence of the mountain range generated a strongly negative mass flux which was only marginally enhanced by mass wasting

multimodal method for coseismic landslide hazard assessment abstract regional scale coseismic landslide hazard assessments have traditionally been based on infinite slope analyses considering only a single mode of failure inventories and landslide reconnaissance work have shown a diverse range of coseismic landslide modes with significantly different consequences of failure this paper presents a multimodal approach for regional scale coseismic landslide hazard assessment through a two step procedure the multimodal method explicitly accounts for four general landslide types commonly observed during earthquakes rock slope failures disrupted soil slides coherent rotational slides and lateral spreads first the susceptibility to each landslide mode is evaluated based on topography second coseismic landslide hazards are assessed using mode specific geotechnical models a trial multimodal landslide assessment is presented for the seismically active country of lebanon results show that the computed coseismic landslide hazard closely matches field verified slope activity across different regions of the country exhibiting a range of failure modes these results qualitatively demonstrate the efficacy of the procedure and suggest that multimodal coseismic landslide hazard analysis is especially well suited for regions with varying terrain and where landslide inventories are not available

holocene environmental signals from mollusk assemblages in burgundy france abstract the malacofaunas of burgundy france reflect changes in climate and the activities of man during the holocene statistical analyses based on the shannon diversity index and correspondence analysis are used to describe the mollusk assemblages in a composite sequence based on three well dated sites the variation demonstrated by the mollusks suggests that a two step warming took place between 10 000 and 9000 and 8000 and 6000 yr b p in relative agreement with the timing of the deglaciation in the tropical atlantic ocean proposed by mix and ruddiman 1985 quaternary science reviews 4 59 108 high humidity partly associated with widespread inundations of the valleys between 10 000 and 8000 yr b p may be related to estimated variations in the rate of freshwater discharge to the atlantic ocean reported by fairbanks 1989 nature 342 637 642 the increasing impact of human activities on the environment during the past 2000 yr is indicated by the low diversity of the mollusk assemblages demonstrating the need for careful interpretation of the youngest holocene sediments in this region

regression models for estimating coseismic landslide displacement newmark s sliding block model is widely used to estimate coseismic slope performance early efforts to develop simple regression models to estimate newmark displacement were based on analysis of the small number of strong motion records then available the current availability of a much larger set of strong motion records dictates that these regression equations be updated regression equations were generated using data derived from a collection of 2270 strong motion records from 30 worldwide earthquakes the regression equations predict newmark displacement in terms of 1 critical acceleration ratio 2 critical acceleration ratio and earthquake magnitude 3 arias intensity and critical acceleration and 4 arias intensity and critical acceleration ratio these equations are well constrained and fit the data well 71 br 2 b88 but they have standard deviations of about 0 5 log units such that the range defined by the mean one standard deviation spans about an order of magnitude these regression models therefore are not recommended for use in site specific design but rather for regional scale seismic landslide hazard mapping or for rapid preliminary screening of sites 2007 elsevier b v all rights reserved

ground motions at the outermost limits of seismically triggered landslides abstract over the last few decades we and our colleagues have conducted field investigations in which we mapped the outermost limits of triggered landslides in four earthquakes 1987 whittier narrows california m 5 9 1987 superstition hills california m 6 5 1994 northridge california m 6 7 and 2011 mineral virginia m 5 8 in an additional two earthquakes 1976 guatemala m 7 5 and 1983 coalinga california m 6 5 we determined limits using high resolution aerial photographic interpretation in conjunction with more limited ground investigation limits in these earthquakes were defined by the locations of the very smallest failures 3 from the most susceptible slopes that can be identified positively as having been triggered by earthquake shaking because we and our colleagues conducted all of these investigations consistent methodology and criteria were used in determining limits in the six earthquakes examined we correlated the outermost landslide limits with peak ground accelerations pgas from shakemap models of each earthquake for the four earthquakes studied by field investigation the minimum pga values associated with farthest landslide limits ranged from 0 02 g to 0 08 g the range for the two earthquakes investigated using aerial photographic interpretations was 0 05 0 11 g although pga values at landslide limits depend on several factors including material strength topographic amplification and hydrologic conditions these values provide an empirically useful lower limiting range of pga needed to trigger the smallest failures on very susceptible slopes in a well recorded earthquake this pga range can be used to identify an outer boundary within which we might expect to find landsliding in earthquakes that are not well recorded mapping the outermost landslide limits provides a useful clue about ground motion levels at the mapped limits

holocene molluscan succession from ne morocco palaeoenvironmental reconstruction and biogeographical implications abstract fluvio lacustrine holocene sequences from the semi arid region of eastern morocco are rich in shells and show similar sedimentary levels that could correspond to synchronous environmental variations the high diversity of moroccan continental malacofaunas makes them a very suitable fossil group for palaeoenvironmental reconstructions and palaeobiodiversity implications the malacological study of blirh is the first in morocco to be based on a systematic sampling providing a complete faunal record in order to reconstruct palaeoenvironmental successions three biozones have been recognized they illustrate occurrence of a marsh and a lake from shortly before 10 600 cal bp followed by an abrupt drying up around 5000 cal bp this dramatic environmental change is not synchronous with lithological variations as stated by previous studies based on geological and palynological records the blirh lacustrine phase fits into the humid period that follows full glacial hyperarid conditions during the latest pleistocene in north africa from 14 800 cal bp the abrupt shift to dry conditions around 5000 cal bp inferred from the malacological succession correlates with the contraction of saharan lakes during the last biozone despite disappearance of the main water body marshy species persist and demonstrate occurrence of very wet environments in the middle moulouya plateau until historical times several species currently absent from the region were found within the holocene assemblages at least two new species of aquatic molluscs hydrobiidae have been discovered sampling of modern malacofaunas from wells and springs in the area has demonstrated that one of them is still living in the water table the blirh malacological record provides an insight of the palaeo biogeographical changes affecting this group during the holocene and demonstrates the very recent increase of human impact on the regional biodiversity

holocene molluscan faunal history and environmental change at kloster muhle rheinland pfalz western germany the holocene molluscan succession presented here from a tufa at kloster muhle near trier is the most detailed yet published from the german bundesland of rheinland pfalz the base of the sequence dated at 9720 75 14c yr bp indicates that the early holocene was characterised by a moist open ground fauna dominated by succinea oxyloma the aquatic phase that follows is short lived bracketed by statistically indistinguishable dates of 9530 60 14c yr bp below and 9695 75 14c yr bp above the establishment of woodland is indicated by the appearance of aegopinella nitidula vertigo pusilla and especially carychium tridentatum which subsequently expands to account for over 40 of the total fauna deciduous forest optimum conditions characterised by the occurrence of platyla polita and helicigona lapicida become established at about 7405 50 14c yr bp the radiocarbon age of 4384 105 14c yr bp obtained for the uppermost tufa horizon is much younger than expected both on the basis of the molluscan fauna observed and the implied decline in the rate of sedimentation in the upper part of the deposit and tufa formation probably ceased much earlier than this date suggests copyright 2002 john wiley sons ltd

environmental change in the vicinity of the neolithic wetland settlement pestenacker s germany during the last 6600 years abstract pestenacker and the adjacent neolithic wetland sites unfriedshausen and pestenacker nord in southern germany belonged to the altheim culture from around 5750 5350 years cal bp in contrast to contemporaneous pile dwellings the houses of pestenacker were constructed at ground level in a wetland environment only little is known about the environmental and hydrological conditions in the direct vicinity of the settlement and how they changed in time to find detailed answers to these questions stratigraphy sedimentology microfossils geochemistry and stable isotopes of a sediment profile immediately to the west of the settlement were studied an age model comprises five radiocarbon dates and dates the base of the profile to about 6600 years cal bp ostracods and aquatic gastropods were frequent only in the basal part of the profile ostracod taxa typical for open water conditions point to higher humidity especially at 6120 5860 years cal bp and 5750 5370 years cal bp sedimentology and organic carbon isotope data confirm this observation thereafter open water habitats disappeared while increasing numbers of non aquatic gastropods occur and soil formation is indicated by elevated 15 n values we conclude that during the time of settlement an open water body existed near by that disappeared shortly after the settlement was abandoned however the spatial extent of this water body still remains to be clarified

a method for producing digital probabilistic seismic landslide hazard maps abstract the 1994 northridge california earthquake is the first earthquake for which we have all of the data sets needed to conduct a rigorous regional analysis of seismic slope instability these data sets include 1 a comprehensive inventory of triggered landslides 2 about 200 strong motion records of the mainshock 3 1 24 000 scale geologic mapping of the region 4 extensive data on engineering properties of geologic units and 5 high resolution digital elevation models of the topography all of these data sets have been digitized and rasterized at 10 m grid spacing using arc info gis software on a unix computer combining these data sets in a dynamic model based on newmark s permanent deformation sliding block analysis yields estimates of coseismic landslide displacement in each grid cell from the northridge earthquake the modeled displacements are then compared with the digital inventory of landslides triggered by the northridge earthquake to construct a probability curve relating predicted displacement to probability of failure this probability function can be applied to predict and map the spatial variability in failure probability in any ground shaking conditions of interest we anticipate that this mapping procedure will be used to construct seismic landslide hazard maps that will assist in emergency preparedness planning and in making rational decisions regarding development and construction in areas susceptible to seismic slope failure

a glacial refugium and zoogeographic boundary in the slovak eastern carpathians although the carpathians in europe have often been considered a glacial refugium for temperate plants vertebrates and molluscs the fossil records the only indisputable evidence surviving glacial periods are as yet scarce moreover the distribution of fossil records is uneven and some areas have remained unstudied we present here three molluscan successions from such an area the border between the western and eastern carpathians this area is not only a geographic border but also a border between the oceanic and continental climate in europe and the molluscan fauna reflects this we found a fluctuation of this zoogeographical border during the late glacial period and the holocene for several snail species with their easternmost or westernmost distribution situated at this border such a fluctuation could reflect a small scale shifting of climate character during the holocene for the first time we recorded the fossil shells of three local endemics carpathica calophana petasina bielzi and perforatella dibothrion we also found a fully developed woodland snail fauna radiocarbon dated to the bolling period this early occurrence of canopy forest snails indicates a possible eastern carpathian glacial refugium for them including local endemics and may reflect a more moderate glacial impact on local biota than expected

influence of spatial variability of soil strength parameters on probabilistic seismic slope displacement hazard analysis abstract permanent sliding displacement analysis is commonly used to evaluate the seismic performance of slopes specifically the fully probabilistic seismic slope displacement hazard analysis pssdha has attracted increasing attention recently since it appropriately accounts for various sources of uncertainties associated with the estimation of sliding displacement within this analysis the uncertainty of soil strength parameters e g effective cohesion c and effective internal friction angle is commonly quantified by a logic tree method in which the spatial variability of c and is simply ignored this study aims at proposing an extended pssdha framework by rigorously accounting for the spatial variability of c and and then investigating its influence on the resultant slope displacement hazard curves based on the newmark rigid block model two different approaches namely an analytical based and a simulation based method are proposed separately the results of the analytical based method are found to be consistent with those obtained by the simulation based one it is also shown that the displacement hazard would be underestimated if the spatial variability of c and is ignored such underestimation is more significant for slopes with soil parameters exhibiting weak c correlation and strong spatial variability besides it suggests that the proper configuration of logic tree framework plays an important role in developing displacement hazard curves and a relatively large range of discrete strength values is recommended to better account for the effect of the spatial variability of soil strength parameters

anomalous concentrations of seismically triggered rock falls in pacoima canyon are they caused by highly susceptible slopes or local amplification of seismic shaking anomalously high concentrations of rock falls were triggered in pacoima canyon los angeles california during the 1994 northridge earthquake similar concentrations were also documented from the 1971 san fernando earthquake using an engineering rock mass classification that evaluates the susceptibility of rock slopes to seismic failure based on the fracture properties of a rock mass in terms of a numerical q value that describes rock quality the rock slopes in pacoima canyon were compared with rock slopes in surrounding areas where topography and lithology are similar but rock fall concentrations from the earthquakes were much lower a statistical comparison of q values from five sites surrounding pacoima canyon indicates that seismic susceptibilities are similar to those within pacoima canyon differences in the characteristics of rock slopes between these sites are not sufficient to account for the relatively high concentrations of rock falls within pacoima canyon as compared to low concentrations elsewhere by eliminating susceptibility differences as a cause the most likely explanation for the differences in rock fall concentrations is anomalously high shaking levels in pacoima canyon possibly resulting from topographic amplification within the canyon manuscript received 21 may 2001

a seismic landslide susceptibility rating of geologic units based on analysis of characteristics of landslides triggered by the 17 january 1994 northridge california earthquake abstract one of the most significant effects of the 17 january 1994 northridge california earthquake m 6 7 was the triggering of thousands of landslides over a broad area some of these landslides damaged and destroyed homes and other structures blocked roads disrupted pipelines and caused other serious damage analysis of the distribution and characteristics of these landslides is important in understanding what areas may be susceptible to landsliding in future earthquakes we analyzed the frequency distribution and geometries of triggered landslides in the santa susana 7 5 quadrangle an area of intense seismic landslide activity near the earthquake epicenter landslides occurred primarily in young late miocene through pleistocene uncemented or very weakly cemented sediment that has been repeatedly folded faulted and uplifted in the past 1 5 million years the most common types of landslide triggered by the earthquake were highly disrupted shallow falls and slides of rock and debris far less numerous were deeper more coherent slumps and block slides primarily occurring in more cohesive or competent materials the landslides in the santa susana quadrangle were divided into two samples single landslides 1502 and landslide complexes 60 which involved multiple coalescing failures of surficial material we described landslide morphologies by computing simple morphometric parameters area length width aspect ratio slope angle to quantify and rank the relative susceptibility of each geologic unit to seismic landsliding we calculated two indices 1 the susceptibility index which is the ratio given as a percentage of the area covered by landslide sources within a geologic unit to the total outcrop area of that unit and 2 the frequency index given in landslides per square kilometer ls km2 which is the total number of landslides within each geologic unit divided by the outcrop area of that unit susceptibility categories include very high 2 5 landslide area or 30 ls km2 high 1 0 2 5 landslide area or 10 30 ls km2 moderate 0 5 1 0 landslide area or 3 10 ls km2 and low

paleoclimatology of the achenheim series middle and upper pleistocene alsace france a malacological analysis abstract the loessic series of achenheim show an uninterrupted stratigraphical sequence dating from the middle and upper pleistocene they contain very abundant paleontological material especially land snails statistical analysis of the malacofaunas multivariate methods has allowed the reconstruction of the climatic evolution of that site during this period five cycles have been recognized which correspond to the glacial cycles b c d e and f comparison with the section of cerveny kopec czechoslovakia indicates the existence of a major climatic event during the pleniglacial of cycle d with a general expansion of the loess steppe in europe an environment which later never appeared in alsace the analogy of the climatic sedimentary sequences of cycle c suggests that alsace and central europe belong to the same geographical entity the development of alsace to an intermediary status between northwestern and central europe

malacological sequence from profile of calcareous tufa in gron podhale basin southern poland as an indicator of the late glacial holocene boundary abstract rich assemblages of subfossil malacofauna were discovered in the profile of slope deposits and calcareous tufas at the gron site in the podhale basin in southern poland the detailed analysis of the composition of this fauna has made it possible to distinguish four types of assemblages their age was established by radiocarbon dating as well as by comparisons with other profiles the malacofauna represented almost exclusively by terrestrial species was used for the reconstruction of the changes in the environment during the sedimentation of the deposits the assemblages distinguished in the study provided the basis for stratigraphic considerations the oldest fauna characterized by a high proportion of cold loving species is typical of the younger dryas the remaining three assemblages are correspondingly linked with the early and middle holocene the evident differences in the composition and structure of the identified malacocoenoses enabled definition of the late glacial holocene boundary the wide geographical distribution of the selected molluscan assemblages enables supra regional correlation and provides an important premise for defining the regional malacostratigraphic subdivisions which can be successfully used to determine the age of deposits from this viewpoint the profile of calcareous tufas in gron represents a model location for central europe

hydrodynamics of floodplain wetlands in a chalk catchment the river lambourn uk variations in floodplain channel water levels and valley floor groundwater levels measured in piezometers and boreholes are examined at selected points along the course of the river lambourn a chalk river in southern england a local alluvial gravel aquifer in the valley bottom is associated with numerous small wetlands that extend over much of the river s perennial profile variations in hydraulic gradient between local borehole levels and or floodplain channel water levels are described for three sites in the seasonal section of the channel at bockhampton east garston and west shefford the results indicate that observed groundwater levels are closely associated with flows from discrete springs at the margins of the channel and floodplain however as the floodplain widens and the alluvial gravel aquifer increases in size the gravel aquifer accounts for a substantial down valley component of groundwater flow with a diffuse vertical water flux in the lower catchment the exchange of flows between the gravel aquifer and the river enables some attenuation of floodplain water table variability providing a stable hydrological regime for valley bottom wetlands catchment controls upon the local valley bottom wetland regime are demonstrated with the application of a simple groundwater model developed using modflow the model is used to simulate groundwater discharge to the river in the upper and lower catchment in addition to the water level regime at selected points in the valley bottom in the lower catchment the results demonstrate the importance of taking catchment scale water flow into account when managing isolated wetlands in a permeable catchment

obtaining suitable logic tree weights for probabilistic earthquake induced landslide hazard analyses abstract in this study an inventory of landslides induced by the 2011 lorca earthquake mw 5 1 has been used in order to develop a new procedure to obtain objective logic tree weights for a probabilistic earthquake induced landslide hazard analysis the 2011 lorca earthquake triggered more than 250 landslides mainly of disrupted type the logic tree was designed having regard to variability of relevant geotechnical parameters involved in the problem and uncertainties associated with the use of several empirical relationships in order to compute newmark displacements for the purpose the resulting hazard maps were compared with this landslide inventory and weights estimated for each branch of the logic tree based on these results the best model for seismic landslide hazard mapping for a moderate earthquake correctly identifies around 72 of landslide areas based on the set of parameters that comprises depth of failure surface specific weight cohesion friction angle and newmark displacement model the corresponding weights were objectively established these weights are reliable enough for the obtaining seismic landslide hazard maps and may be implemented in similar environments characterized by moderate low magnitude earthquakes mw

the influence of different simplified sliding block models and input parameters on regional predictions of seismic landslides triggered by the northridge earthquake abstract regional seismic landslide hazard maps are based on predictions of rigid sliding block displacement derived from estimates of earthquake ground shaking topography geology and shear strength the confidence in these predictions requires comparisons with field observations of landslide occurrence during previous well documented earthquakes this paper presents a comparison between observed landslides from the 1994 northridge california earthquake and predicted landslides based on sliding block displacement estimates seven empirical displacement models each of which uses a different combination of ground motion parameters are investigated to evaluate which models and associated ground motion parameters best predict seismic landslides using best estimates of ground shaking and shear strength properties from the northridge earthquake sliding displacements are calculated and compared with the locations of observed landslides only 20 40 of the observed landslides are captured and the total area of predicted landslides is much larger than observed the ability to predict landslide occurrence accurately depends less on the displacement model and associated ground motion parameters and more on the uncertainty in the model parameters particularly the assigned shear strengths because current approaches do not take into account the spatial variability of shear strength within individual geologic units the accuracy of the predictive models is controlled predominantly by the distribution of slope angles within a geologic unit assigning overly conservative low shear strength values results in a higher percentage of landslides accurately identified but also results in a large over estimation of the total landslide area making more accurate maps of seismic landslide hazards will require methods to define intra formational variations in shear strength

late glacial and holocene malacofaunas from archaeological sites in the somme valley north france the first malacological successions covering the late glacial period and the early holocene are reported from archaeological sites in northern france five malacological zones s1 5 are recognized which are related to the regional lithostratigraphy upper palaeolithic mesolithic archaeology and to a radiocarbon chronology the zone s1 which contains an assemblage of low species diversity but with abundant vallonia allows attribution of the basal loess reworked as a rainwashed silt in the valley bottom to the early late glacial rather than the pleniglacial overlying the loessic sediments is an organic silt known as the belloy soil w at belloy which has yielded birch pollen but no pine allowing attribution to the early part of allerod phase of the late glacial the molluscan faunas from this level s2 are richer and more diverse helicopsis striata muller appears to be typical of this period above the allerod deposit is a minerogenic silt containing rhizomes but this is only represented in the valley floors the malacofaunas from this unit s3 are similar to those of the allerod silt but contain a higher proportion of hygrophilous taxa these faunas are assigned to the younger dryas a conclusion supported by radiocarbon dating of bones associated with the terminal upper palaeolithic industrie a pieces m churees which occur at the top of the unit the late glacial succession is overlain by organic silts of holocene age which at several sites have yielded mesolithic artefacts the molluscan faunas are much more diverse than the earlier late glacial assemblages and contain abundant shade demanding taxa s4 then a fall in species diversity and a reversion to faunas of open ground occur s5 comparison of these successions with similar sites in burgundy the paris basin and southeastern england demonstrate a closer affinity to the molluscan sequences of kent rather than to the french sites although late glacial molluscan faunas are still poorly known from france

a holocene molluscan succession from floodplain sediments of the upper lena river lake baikal region siberia floodplainsediments of the upperlenariver near basovo in south central siberia have yielded the most detailed holocenemolluscansuccession yet reported from the entire eastern palaearctic over 72 500 shells from at least 28 species of terrestrial and 23 species of freshwater mollusc have been recovered an abundance and diversity far higher than previously reported from the region the molluscan assemblages are dominated by land snails especially members of the genus vallonia represented by five species including vallonia tenuilabris and two poorly known species vallonia kamtschatica and vallonia cf chinensis other noteworthy species recovered include gastrocopta theeli carychium pessimum vertigo extima southernmost record vertigo microsphaera and the first asian records of three other taxa vertigo geyeri vertigo genesii and vertigo parcedentata illustrations are provided for the critical species since opinions differ about the status of various taxa and the correct names that should be used the molluscan assemblages show clear successional trends during the early to mid holocene reflecting episodes of dryness wetness on the floodplain drier conditions at ca 6350 14c yr bp coincide with major changes in the archaeological record seen at other sites in the region but it remains unclear whether the two are linked a prominent charcoal rich horizon dated to ca 2800 14c yr bp marks a burning event in the catchment which resulted in a two fold increase in sediment accumulation rate remains of small mammals occurred throughout the sequence including a tooth of microtus cf maximowiczii possibly the first occurrence of ungar vole west of lakebaikal the faunal analyses have been integrated with a detailed pedological study of the sedimentary profile and a chronology was obtained by means of 12 ams radiocarbon dates this study provides the first detailed palaeoecological information relating to holocenemolluscan assemblages from the cis baikalregion and lays the foundation for future work in the eastern palaearctic

holocene pollen stratigraphy and human interference in the woodlands of the northern apennines italy pollen stratigraphic data and radiocarbon dates are presented for a full holocene series of sediment cores obtained from a high level site in the appennino parmense northern italy three marker horizons are identified on the basis of sediment changes and pollen stratigraphy and the extent to which they indicate episodes of significant human interference in the local vegetation is discussed the earliest m1 is dated to around 6300 bp from the pollen evidence some form of human impact on the regional vegetation at this time is suspected but there is no convincing archaeological evidence to support this the pollen evidence from the second m2 5000 4000 bp and third m3 ca 1400 bp marker horizons is consistent with archaeological information in suggesting that the high parts of the apennines close to the tree line were subject to intense summer grazing during the late neolithic through to the copper age and the immediate post roman period a review of archaeological and documentary evidence

quantifying groundwater discharge from different sources into a mediterranean wetland by using 222rn and ra isotopes summary groundwater discharge constitutes the main water inflow of many coastal wetlands despite the potential of ra isotopes and 222rn as tracers of groundwater discharge the use of these radionuclides to quantify the groundwater inflow in coastal wetlands has been only scarcely addressed in the literature the main goal of this study is to evaluate the use of 222rn and ra isotopes to estimate the contribution of distinct groundwater sources into a mediterranean coastal wetland the peniscola marsh castello spain the peniscola marsh is a small shallow wetland nourished by groundwater coming from four different flowpaths i a deep flow from the regional carbonate aquifer of el maestrat ii a shallow flow and iii an intermediate flow both from the irta range and the detritic vinaros peniscola aquifer and iv seawater intrusion data on 226ra 222rn and salinity obtained in summer 2007 revealed that the deep groundwater contribution was 15 of the total water inflow whereas the shallow and intermediate flow paths represented 32 and 48 respectively seawater accounted only for the remaining 5 inputs to the wetland ra isotopes also allowed estimating the marsh water age in 1 2 days both the groundwater contributions derived from 222rn measurements and the ra derived marsh water age agreed well with the direct measurements obtained using propeller flow meters evidencing the effectiveness of the used methods an interannual comparison between the estimated groundwater inflow and the precipitation revealed that shallow groundwater flows respond to local precipitation whereas the deep groundwater flow from the carbonate aquifer is dominated by a constant baseflow

calcium concentrations in wetland groundwater in relation to water sources and soil conditions in the recharge area schol p p and wassen m j 1993 calcium concentrations ill wetland groundwater in rehtlion to water sou rces a nd soil conditions in tile recharge area j hydrol 141 197 217 over the past several decades vegetation eommunities i lowland wetlands in western europe have changed species rich love productivity i e low primary bion ss production communities characteristic of rich fens fens characterized by alinc ophilous specms have declined and are being replaced by vegetation communities characterislic of high productivity rich fens poor fens fens characterized by nmbrophilous specicsi and bogs high concentrations of calcium ie groundwater are generally believed to bc an important controlling factor on the vegetation of rich fens management for the protection of low productivity rich fells therefore generally aims at conscrvution of calcareous groundwater conditions in the rool zone of lowland wetlands this paper relates the occurrence of calcium rich groundwaler in t wland e ellands of the central nether ands to water sources and soil conditions in the groundwater recharge area the chemical compostlion of the following groundwater types is compared groundwater recharged at a sandy ridge adjacent to tile wclhmd area ridge walcr groundwater recharged by precipitation witnn the wetland peat water groundwater recharged by surface water in the wetland objective hydrological criteria arc used to classify gr mndwater analyses according to recharge area oxygen 18 proved an essentia 1 criterion for the distinclion between genetic groundwater types it is therefore recommended to make oxyt en 18 analysis standard proccdm e ill geo lydrological wetland research calcium concentrations are generall not suitable as tracers of different types of recharge areas all groundwater types contain calcium in contrast to what is generally assnrned lowest concenlralions arc observed in ridge waler iligher calcium concentrations are found in gronndw ler recharged in wctllnlds especially ill intihratcd surface water nutrient concenlralinns in both ridge a d peal water are imv while those in iniilttaled surface water are signilicant y higher the nlain conclusion for nature clmservalion is thai calcium rich and me otrophie cot ri ions ill the rot l zone can he realised not only by the seepage of groundwater from upland sandy rechar ge areas as is generally thought but also by the seepage of peat water this is important as a severe dete foration ill the quality of mdge water seeping upward on the river plain may be anticipated in tile near fut rc which forms a threat to low productivity rich fens peal water may olll r an alternativc water source ibr the conservatkm or regeneration of tow productivity rich t ns

geochemistry and hydrology of a calcareous fen within the savage fen wetlands complex minnesota usa abstract savage fen is a wetlands complex at the base of north facing bluffs in the minnesota river valley the complex includes 27 8 hectares of calcareous fen that host rare calciphile plants whose populations are declining in minnesota water and sediment compositions in the calcareous fen were studied to gain a better understanding of the hydrologie system that sustains the rare vegetation groundwater in the fen is a calcium magnesium bicarbonate type with circumneutral ph values the groundwater composition is the resuit of interactions among water dissolved and gaseous carbon species carbonates and ion exchangers shallow groundwater is distinguished from deep groundwater by smaller concentrations of chloride sulfate magnesium and sodium and larger concentrations of calcium bicarbonate hydrogen sulfide and ammonium magnesian calcite is the prevalent carbonate in unconsolidated sedimentary fill beneath the fen and is an important source and sink for dissolved calcium magnesium and inorganic carbon calcite concentrations just below the water table are small because aerobic and anaerobic oxidation of organic matter increase the partial pressure of carbon dioxide pco2 decrease ph and cause calcite to dissolve thick calcite accumulations just above the water table in the root zone of calciphile plants resuit from water table fluctuations and attendant changes in pco2 groundwater beneath savage fen recharges in lakes and ponds south of the fen and upwells to the surface within the fen water at the water table is a mixture of upwelling groundwater and water near the surface that flows downslope from higher elevations in the fen changes in oxygen and hydrogen isotope compositions of shallow groundwater indicate that the proportion of upwelling groundwater in shallow groundwater decreases downgradient in the calcareous fen encroachment of reed grasses into the calcareous fen may reflect human caused disturbances in the recharge area

dynamic analysis of a slope failure from the 6 august 1979 coyote lake california earthquake abstract the coyote lake california earthquake of 6 august 1979 m l 5 7 provided a rare opportunity to perform a dynamic numerical analysis of a seismically induced slope failure using actual strong motion records the earthquake displaced a preexisting slump on the northeast shore of lake anderson and formed a fissure 20 m long offsets of 9 mm vertically and 18 mm horizontally were measured across the fissure the slump is 9 km northwest of the located epicenter but within 100 m of the mapped trace of the calaveras fault two strong motion records were written in the vicinity of the slump coyote creek 5 km to the southeast and gilroy 6 15 km to the southeast these records combined with field measurements of the slope estimates of the material properties and a dynamic numerical model based on the newmark analysis of seismic slope stability to calculate a predicted displacement for the landslide a displacement of 27 mm calculated using the n50 e component of the gilroy 6 record is in excellent agreement with the displacement measured in the field 21 mm however displacements of only 0 12 mm calculated using the 250 component of the coyote creek strong motion record reflect significant local variations in seismic shaking intensity because strong motion records and slope failures rarely coincide this landslide provides an important test case for our understanding of the dynamics of seismically induced landslides as well as a warning that local seismologic variations need to be considered in any design applications

probabilistic mapping of earthquake induced submarine landslide susceptibility in the south west iberian margin abstract the sw iberian continental margin is well recognized as a tectonically active area where major canyons and mass wasting events are both present earthquake triggered submarine landslides may cause tsunami and result in catastrophic damage to bordering coastal areas in this setting submarine landslide susceptibility mapping represents a major step towards a regional risk mitigation strategy landslide susceptibility mapping in large offshore areas presents significant challenges as a result of the limited information on controlling variables large uncertainties in triggering mechanisms and limited geotechnical data in this study a geotechnical model based approach has been followed that narrows the range of controlling factors and within a probabilistic framework allows a systematic treatment of parameter uncertainties this model based analysis covers the whole sw iberian margin increasing by three orders of magnitude the areal extent of precedent offshore slope stability susceptibility studies this jump in spatial scale is facilitated by application of a systematic bayesian updating procedure to combine geotechnical information from global databases and that available from regional sites seismic shaking is estimated using an available regional database of seismogenic faults these tools are implemented within a gis to generate via montecarlo simulations probabilistic landslide susceptibility maps based on two different analytical seismic infinite slope stability models these models differ mainly in the form of their final results either as distributions of slope stability safety factors or as distributions of seismic triggered slope displacements receiving operator curves are used to assess the different landslide susceptibility predictions obtained against a comprehensive regional database of submarine landslides it turns out that the models analyzed correctly predict 92 and 82 of the mapped landslide subset chosen for validation for pseudo static and displacement based method respectively this suggests that within the limits of the currently available databases seismic events are the dominant factor at the origin of the submarine landslides mapped in the study area an advantage of the framework presented is that it can quickly incorporate new regional geotechnical information or better regional landslide databases as they become available

slope unit based approach for assessing regional seismic landslide displacement for deep and shallow failure abstract grid based approach is typically adopted to estimate the newmark type displacement for regional seismic landslide hazard assessment however the approach is limited to the assumption of infinite slope and rigid block movement which may be different from the actual behavior of slope under seismic loading in this study a slope unit based approach is proposed to quickly estimate earthquake induced displacements for finite slopes in regional scale hence regional seismic landslide hazard can be assessed by the estimated displacements the approach is advantageous as it considers slope geometry determines the failure mode automatically and considers the interaction of incident wave and slope the implementation of the approach is demonstrated by considering two areas that experience severe landslides during the chi chi and northridge earthquakes results show that the prediction rate of the proposed method is up to 73 compared with the landslide inventory given the estimated displacements

three detailed radiocarbon dated holocene tufa and alluvial fan mollusc successions from southern ontario the first in northeastern north america abstract fossil mollusc remains particularly those of land snails provide a wealth of detailed information concerning local quaternary paleoenvironments and regional paleoclimatic conditions however this important resource is generally overlooked in north america and consequently quantitative well dated terrestrial mollusc successions are extremely rare here in an attempt to redress this imbalance a project examining the holocene molluscan faunal history of northeastern north america has been initiated thus far detailed mollusc successions and associated radiocarbon age determinations have been obtained from three sites in southern ontario two alluvial fans chine drive fan and cudia park fan both from the scarborough bluffs east of toronto and a tufa west river road near cambridge the observed land snail successions to provide an initial view of the molluscan faunal history of this region during the period from the late glacial to the mid holocene between approximately 10 500 and 5000 radiocarbon years bp yr bp the molluscan data have also been used to reconstruct the paleoenvironmental history of southern ontario during this time documenting the progression from exposed open habitats characterised by species such as vertigo modesta vallonia albula columella columella and vitrina angelicae limpida to closed woodland biotopes indicated by the presence of taxa including carychium nannodes nesovitrea binneyana paravitrea multidenta and helicodiscus parallelus this study has already demonstrated the potential of this technique in the study of quaternary climatic and environmental change in eastern north america and represents a strong foundation for extending the analysis of fossil land snail successions to other sites throughout this region it has also provided new and important insights into the establishment of the modern molluscan fauna which are essential to the understanding of present day distributional patterns and environmental associations

mollusc succession of a prehistoric settlement area during the holocene a case study of the ceske středohoři mountains czech republic some central european areas were attractive for the first agricultural settlements due to their suitable natural conditions the holocene development of such areas was thus under long term human pressure whose impact on the whole landscape is still poorly understood one of such areas is the ceske st edoho i mountains while pollen analyses can provide the general pattern of the landscape development the analyses of mollusc succession provide landscape details which are important primarily in landscapes with high habitat diversity based on the study of 11 mollusc successions situated at the ceske st edoho i mountains we describe the postglacial development of the area and show the moderate fluctuation of woodland wetland and open country habitats without any distinct succession peaks of particular habitat types during the whole holocene however a detailed look of species exchange has provided additional information of succession pattern the impoverishment of woodland communities is probably cause