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

regional scale co seismic landslide assessment using limit equilibrium analysis abstract traditionally regional assessment of seismic slope stability has been done using the infinite slope rigid sliding block analysis a major disadvantage of this approach is the resulting overestimation of the critical acceleration of the slope due to the underlying assumption of a predefined slope failure plane and consequently the underestimation of hazard areas prone to sliding in this paper we present a modified approach for assessing seismic slope instabilities using a model based on limit equilibrium analysis and circular slip surfaces with no restriction to any predefined slope failure plane for this purpose we conduct a parametric study to identify the relationship between the critical acceleration of the slope the slope angle and the slope shear strength parameters we model typical slopes in the rocscience software slide using bishop s limit equilibrium method to identify the critical accelerations that corresponds to a failure plane with factor of safety equal to one the critical accelerations were plotted against the variables in the parametric study and the best fit equations were obtained the proposed approach was developed for global application but it was tested using the well documented co seismic landslide database of the 1994 northridge ca earthquake the predicted sliding areas were compared to the inventory of landslides that were triggered in the val verde region in los angeles by the earthquake qualitative and quantitative assessments of the proposed model clearly show its advantages in predicting potential sliding areas

case history of landslide movement during the northridge earthquake we document a case history of northridge earthquake induced movement of a coherent landslide mass comprised principally of weathered previously sheared siltstone information on the residual shear strength of the material through which the sliding occurred is available both from backanalysis of a static rainfall induced failure on the same slope and laboratory test data postearthquake field reconnaissance data establishes the seismic slope displacements near the slope crest a yield coefficient is estimated for the slope based on residual shear strengths and measured groundwater levels at the time of the northridge earthquake this yield coefficient is used with four horizontal equivalent acceleration time histories that approximate the seismic demand within the slide mass in newmark sliding block displacement analyses the calculated displacements range from approximately 20 to 90 mm which compares well with observed displacements at the slide scarp of approximately 50 mm

chronology and human settlement in northeastern patagonia argentina patterns of site destruction intensity of archaeological signal and population dynamics temporal frequency distributions are used to assess the chronology and continuity of human occupation at different spatial scales differential landscape use and demographic patterns throughout time these issues were addressed by applying the summed of radiocarbon probability distributions method to the northeastern sector of patagonia argentina this sector was divided into three microregions the lower course of the colorado river the mouth and the middle and lower course of negro river and the north coast of san matias gulf differences in the chronology of the occupations are observed when considering individually the three micro regions also differences are recorded regarding the chronological pattern obtained from coastal and inland sectors these differences are mainly the outcome of specific geomorphological processes operating in different sectors of landscape that generated taphonomic bias sites were differentially impacted by taphonomic factors and the recognition of older sites than middle and late holocene is difficult despite the detection of taphonomic biases it is proposed that the higher intensity of the archaeological signal for the final late holocene ca 600 400 cal bp would be the result of higher population densities it is suggested that chronological patterns obtained by temporal frequency distributions should be strengthened by independent evidence provided by qualitative information on the reorganization of hunter gatherer societies e g changes in burial practices subsistence technology etc indispensable to better evaluate the increase in population size and prehistoric demography

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

radiocarbon dates as data quantitative strategies for estimating colonization front speeds and event densities abstract archaeological analysis of large scale prehistoric population history requires us to estimate rates of spatial spread during dispersals and rates and magnitudes of temporal contraction during crashes using oxcal s mcmc sampling routine i introduce and demonstrate a simple and easily implemented method of estimating front speeds that takes due account of the uncertainty in the archaeological data in both dates and distances and argue that this method is more appropriate than those most often used in front speed estimation at present i also propose a simple and easily implemented method of estimating event densities as a demographic proxy as an alternative to summed calibrated probability distributions i argue that this alternative is a significantly better technique and show that its use also enables us to identify individual archaeological dates that are exerting particularly strong influence on the results so that we can efficiently allocate our attention when assessing the possible effects of exogenous sampling uncertainty to illustrate these methods i re analyse two published datasets relating to the early paleoindian colonization of north america my results with the new technique indicate that even with a very noisy dataset there was clear evidence in the framework of the intcal04 calibration curve for a drastic reduction in archaeological event densities following the younger dryas onset followed by a prolonged period of reduced human activity and a possible renewed phase of rapid growth after the younger dryas termination and onset of the holocene however the revised estimate of the younger dryas marine reservoir offset in the intcal09 calibration curve for 12 550 12 900 cal bp changes the picture significantly by flattening the peak in clovis age events and pushing it forward in time into the early younger dryas itself

earthquake induced displacements of solid waste landfills the response of municipal solid waste landfills at high levels of earthquake shaking is explored results from fully nonlinear dynamic analyses indicate that the seismic response of a landfill particularly the seismic loading for the cover can vary significantly due to reasonable variations of waste properties fill heights site conditions and design rock motions however for the base sliding case the maximum seismic loading depends primarily on the amplitude peak acceleration and frequency content mean period of the design rock motion and the dynamic response characteristics of the landfill represented by its initial fundamental period the calculated permanent base displacement is largely a function of the k sub y k sub max ratio but it is also influenced significantly by the intensity frequency content and duration of the design rock motion and the dynamic response characteristics of the landfill and its foundation charts with normalized parameters are presented which aid in the development of preliminary estimates of the expected seismic loading and displacement these analytical results are consistent with observations from available case records

a parametric numerical study of the interaction between seismic waves and landslides for the evaluation of the susceptibility to seismically induced displacements this study presents the results of a numerical analysis investigating the influence of the interaction between seismic waves and slopes on seismically induced displacements of existing landslides three step like slope geometries with dip angles varying from 10 degrees to 45 degrees and two landslide mechanisms were considered 54 multi frequential dynamic equivalent signals were applied to the models and were derived according to the lema des approach based on the accelerometric records of the european strong motion and cosmos databases the simulations were performed using a finite difference approach that assumed different viscous rheologies and considered different values for both the dynamic properties and the mechanical parameters the interaction between seismic waves and landslides was analyzed using frequency ratios defined for characteristic periods associated with the landslide dimensions i e thickness and length and the seismic input a regression analysis was also performed to derive correlations between seismically induced displacements and the frequency ratios the values of the arias intensity and the critical accelerations the obtained results reveal that a the seismically induced displacements increase with the seismic amplification induced by the landslide mass b the coupling of a 2d interaction between seismic waves and slope with the 1d resonance of the landslide mass which is strictly related to the high impedance contrasts between the landslide mass and the substratum significantly affects the seismically induced displacements and c the seismically induced displacements increase more intensely with increasing slope angle for a rototranslational mechanism with respect to a translational one moreover the seismically induced displacements that can be expected from the here obtained results can significantly differ from those computed by the sliding block stability analyses based on newmark s method

middle to late holocene environmental changes in bajo de la quinta ne patagonia inferred by palynological records and their relation to human occupation the north patagonian region between 38 and 42 s extends along the proximity of two major atmospheric circulation features in south america the northern border of the southern westerly circulation belt and the northeast trade wind circulation associated with the subtropical south atlantic anticyclone the influence of this westerly wind system determines the annual and seasonal precipitation regimen in north patagonia while the influence of the south atlantic anticyclone is more pronounced towards the east the changing strength of either of these circulation systems has had a strong influence on holocene environmental change in the region palaeoenvironmental changes are inferred from a 500 cm long core from bajo de la quinta 40 55 42 s 64 20 19 w by means of pollen sediment and geomorphological analyses a dry phase with westerly winds during the middle holocene at around 7000 6600 cal yr bp is indicated by xerophytic psammophytic vegetation and patagonian steppe components between 6600 and

simplified procedure for estimating seismic slope displacements for subduction zone earthquakes abstractseismic slope displacements are estimated for earth structures or natural slopes subjected to interface earthquakes in subduction zones the fully coupled nonlinear seismic slope displacem

late holocene climatic fluctuations and soil genesis in southern patagonia effects on the archaeological record geoarchaeological research conducted at five localities in southern patagonia and tierra del fuego identified a mollisol within late holocene aeolian and colluvial deposits associated with archaeological material the mollisol s origin and development are related to an increase in humidity c 1000 bp following an episode of severe drought during the medieval warm period corroborating data is supplied from dendroclimatic and pollen studies a drastic reduction in frequency of artefact distribution recorded at the sites studied corresponds to this pedologic event suggesting a greater human presence at these sites during earlier regional scale arid conditions however the paucity of archaeological remains may also be the result of the low resolution of cultural evidence following the pedologic development due to superimposition over previous archaeological deposits

the role of shear and tensile failure in dynamically triggered landslides summary dynamic stresses generated by earthquakes can trigger landslides current methods of landslide analysis such as pseudo static analysis and newmark s method focus on the effects of earthquake accelerations on the landslide mass to characterize dynamic landslide behaviour one limitation of these methods is their use mohr coulomb failure criteria which only accounts for shear failure but the role of tensile failure is not accounted for we develop a limit equilibrium model to investigate the dynamic stresses generated by a given ground motion due to a plane wave and use this model to assess the role of shear and tensile failure in the initiation of slope instability we do so by incorporating a modified griffith failure envelope which combines shear and tensile failure into a single criterion tests of dynamic stresses in both homogeneous and layered slopes demonstrate that two modes of failure exist tensile failure in the uppermost meters of a slope and shear failure at greater depth further we derive equations that express the dynamic stress in the near surface in the acceleration measured at the surface these equations are used to approximately define the depth range for each mechanism of failure the depths at which these failure mechanisms occur suggest that shear and tensile failure might collaborate in generating slope failure

motions of gently sloping ground during earthquakes 1 during past earthquakes gently sloping ground surfaces have been observed to shift laterally over areas as large as a few square kilometers these permanent downward motions have been attributed to temporary and partial reductions in shear strength of soil deposits e g liquefaction static gravity forces and transient earthquake shakings these motions the amplitudes of which remain challenging to predict have been frequently modeled using newmark sliding blocks for ground that is statically stable and occasionally partially or completely loses its shear strength during earthquakes this paper investigates in more details the deformations of gently sloping ground that becomes temporarily unstable under the combined effects of gravitational forces and earthquake shakings using a physical model we propose two definitions of earthquake contributions to the displacement of gently sloping ground which may include or not the effects of initial velocity in both cases monte carlo simulations reveal that motions of gently sloping ground are influenced by pulses of earthquake ground velocity for a wide range of reduction in soil shear strength even for very severe loss of shear strength for practical purposes when large soil deposits become unstable during earthquakes the analysis concludes that the motions of gently sloping ground are likely influenced by earthquake ground velocity

evaluation of simplified methods for predicting earthquake induced slope displacements in earth dams and embankments abstract this paper provides a review and comparison of existing simplified displacement based sliding block models analyses were performed to evaluate the relative accuracy of fifteen of these simplified models for predicting earthquake induced displacements to accomplish this task the predictive capability of the models was assessed by comparing model predictions with the actual displacements that were observed after earthquake shaking in 122 case histories of earth dams and embankments the results indicate that the model predictions of displacement were less than the observed displacement for a large majority of the case histories that were examined the difference between the observed and predicted displacements was relatively large for a significant percentage of the cases for each model that was examined the shapes and positions of the models relative error cumulative distribution functions did not change significantly if the case histories were filtered to include only those with intermediate levels of observed displacement i e 0 01 m

challenging intensification human environment interactions in the holocene geoarchaeological record from western new south wales australia an intensification theory was developed in australian archaeology in the early 1980s from a desire to make the study of australian hunter gatherers closer to theoretical developments in hunter gatherer studies elsewhere an apparent increase in the quantity and range of archaeological deposits was interpreted as demonstrating a combination of population increase and increased social complexity beginning 2 3000 years bp data were amassed in support of the theory but with only one or two exceptions they were not directly tested here we report on a series of studies that permit us to formulate a test for one aspect of the intensification theory chronologies constructed using osl determinations of sediments are combined with the results of age determinations obtained from hearth charcoal to develop an envelope of time for human occupation of the southeast margin of the australian arid zone the results indicate that the apparent increase in the quantity and range of archaeological materials in the late

unconventional pseudostatic stability analysis of the diezma landslide granada spain based on a high resolution engineering geological model abstract a novel unconventional pseudostatic analysis is proposed here to infer on the sensitivity of a landslide to earthquakes characterized by different physical properties several sine waves with different amplitudes frequencies and phases were applied to the landslide mass assuming limit equilibrium conditions the unconventional approach was used for the diezma landslide case study the landslide is located 25 km from the city of granada spain although the slope had repeatedly suffered small scale stability problems since the construction of the a 92 highway a larger failure occurred on 18 march 2001 and damaged the highway between kilometers 272 6 and 272 8 the landslide had an estimated volume of 1 2 mm 3 and involved a disordered deposit of silt and clay with heterometric blocks within the numidoide formation which outcrops along the contact between the malaguide and dorsal domains of the betic cordillera mountain range despite the 18 million euros spent since 1999 on geotechnical investigations and stabilization solutions the numerous reactivations that occurred through 2010 and 2013 demonstrate the persistent activity of the landslide the geometry of the large slope failure corresponding to the first activation of the diezma landslide was used to back analyze the stability of the slope based on a high resolution engineering geological model the model was developed from the analysis of numerous borehole logs as well as from geophysical investigations consisting of seismic noise measurements the results demonstrate that the safety factor sf of the diezma landslide varies significantly for frequencies less than 1 hz moreover unstable conditions are reached at frequency values between 0 5 and 1 hz for water pressure distributions corresponding to bishop factors r u between 0 and 0 36 to estimate the co seismic displacements the geometrical and mechanical properties of the landslide mass were used to derive its characteristic periods for thickness t s and length t l which were compared with the characteristic period of the earthquake t m the results indicate that the maximum expected co seismic displacements are up to 2 m for an earthquake with a t m value close to 1 s and an arias intensity on the order of 1 m s

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

modified newmark model for seismic displacements of compliant slopes newmark sliding block analyses are widely used for estimation of permanent displacements of slopes in earthquakes the conventional newmark model however neglects the dynamic response of the material above a potential failure surface decoupled procedures have been developed to account for that response but they neglect the effects of permanent displacements on the response a modified newmark analysis that considers the dynamic response including the effects of permanent displacements of the material above the failure surface is presented the modified newmark analysis shows that the decoupled approach produces somewhat conservative estimates of permanent displacements for stiff and or shallow failure masses but that it may produce unconservative estimates for failure masses that are soft and or deep many slopes of large lined landfills may fall into this latter category the notion of a slope spectrum which illustrates the effect of the natural period of a potential failure mass on permanent slope displacement is also introduced

methods for assessing the stability of slopes during earthquakes a retrospective abstract during the twentieth century several methods to assess the stability of slopes during earthquakes were developed pseudostatic analysis was the earliest method it involved simply adding a permanent body force representing the earthquake shaking to a static limit equilibrium analysis stress deformation analysis a later development involved much more complex modeling of slopes using a mesh in which the internal stresses and strains within elements are computed based on the applied external loads including gravity and seismic loads stress deformation analysis provided the most realistic model of slope behavior but it is very complex and requires a high density of high quality soil property data as well as an accurate model of soil behavior in 1965 newmark developed a method that effectively bridges the gap between these two types of analysis his sliding block model is easy to apply and provides a useful index of co seismic slope performance subsequent modifications to sliding block analysis have made it applicable to a wider range of landslide types sliding block analysis provides perhaps the greatest utility of all the types of analysis it is far easier to apply than stress deformation analysis and it yields much more useful information than does pseudostatic analysis

probabilistic assessment of seismic stability of a rock slope by combining the simulation of stochastic ground motion with permanent displacement analysis abstract a probabilistic framework that considers the variability and uncertainty of the ground motions caused by earthquakes and the parameters of the slope material is proposed to assess the seismic stability of rock slopes a stochastic ground motion simulation method which reflects certain earthquake scenarios and site characteristics was used to generate accelerograms as seismic inputs then the probabilities of failure pf of the slopes when subjected to earthquake ground motions were computed via monte carlo simulations based on the simulated ground motions and the decoupled newmark permanent displacement analysis an example rock slope was used to illustrate the proposed procedure and verify its rationality the results showed that the magnitudes of the earthquakes and the source to site distances had significant influences on the seismic stability of the slopes for an earthquake of the same magnitude the pf of the slope decreased rapidly as the source to site distance increased in addition given the same source to site distance the pf of the slope increased steadily as the magnitudes of the earthquakes increased also it was found that the influence of coefficient of variation of the slope s shear strength parameters i e c was not negligible when the uncertainty of earthquakes was not considered however it may be overshadowed by the significant influence of a great earthquake especially when the variability of ground motions is taken into account the results that were obtained agreed well with observed earthquake induced landslide phenomena and the statistical data of two typical earthquakes that occurred in japan and china which implies that the proposed method is accurate

the effects of normal and shear stress wave phasing on coseismic landslide displacement predictive models used to assess the magnitude of coseismic landslide strain accumulation in response to earthquake ground shaking typically consider slope parallel ground accelerations only and ignore both the influence of coseismic slope normal ground accelerations and the phase relationship between dynamic slope normal and slope parallel accelerations we present results of a laboratory study designed to assess the significance of the phase offset between slope normal and slope parallel cyclic stresses on the generation of coseismic landslide displacements using a dynamic back pressured shearbox that is capable of simulating variably phased slope normal and slope parallel dynamic loads we subjected sediment samples to a range of dynamic loading scenarios indicative of earthquake induced ground shaking we detail the variations in strain accumulation observed when slope normal and slope parallel stresses occur independently and simultaneously both in and out of phase using a range of dynamic stress amplitudes our results show that the instantaneous phasing of dynamic stresses is critical in determining the amount of coseismic landslide displacement which may vary by up to an order of magnitude based solely on wave phasing effects instantaneous strain rate is an exponential function of the distance normal to the mohr coulomb failure envelope in plots of shear stress against normal effective stress this distance is strongly controlled by the phase offset between dynamic normal and shear stresses our results demonstrate that conditions considered by conventional coseismic slope stability models can either overestimate or underestimate earthquake induced landslide displacement by up to an order of magnitude this has important implications for accurate assessment of coseismic landslide hazard

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

the use of summed radiocarbon probability distributions in archaeology a review of methods abstract using a database of australian archaeological radiocarbon dates n 2996 this paper explores three key methodological issues associated with the use of summed probability plots of radiocarbon data 1 the minimum sample size needed for a statistically reliable plot 2 the effect of radiocarbon calibration on the structure of these plots and 3 the application of a taphonomic correction to such time series data the results identify several protocols recommended as best practice when using summed probability plots 1 a minimum sample size of 500 radiocarbon dates should be used and the sample size and the mean of the standard deviations of the radiocarbon dates t in the sample should both be reported 2 a moving average trendline of 500 800 years should be used to offset the effects of the calibration process and 3 surovell et al correcting temporal frequency distributions for taphonomic bias journal of archaeological science 36 2009 1715 1724 is explored with modifications and temporal limits

simplified frequency content estimates of earthquake ground motions it is often useful in earthquake engineering practice to characterize the frequency content of an earthquake ground motion with a single parameter three simplified frequency content parameters are examined mean period t m predominant period t p and the smoothed spectral predominant period t o these frequency content parameters are calculated for 306 strong motion recordings from 20 earthquakes in active plate margin regions these data are used to develop a model that describes the magnitude distance and site dependence of these frequency content parameters nonlinear regression analyses are performed to evaluate model coefficients and standard error terms the results indicate that the traditional t p parameter has the largest uncertainty in its prediction and that previous relationships proposed to predict t p are inconsistent with the current data set moreover t m is judged to be the best simplified frequency content characterization parameter and it can be reliably estimated

earthquake response and sliding displacement of submarine sensitive clay slopes abstract many submarine landslides occur through marine sensitive clay layers and the strain softening behavior plays a key role the changing soil properties induced by various disturbances will have marked impact on earthquake performance of submarine clay slopes in the present study undrained triaxial compression tests on reconsolidated samples of a soft sensitive marine clay were conducted and a soil disturbance dependent simple constitutive model is proposed for describing post peak nonlinear strain softening behavior of sensitive clays based on experimental results and then is implemented in quiver code to perform one dimensional seismic response analysis of mild infinite slopes to address the relative importance of soil disturbance effect on the site response and sliding displacement of submerged slopes during seismic loading detailed laboratory test descriptions and results of a soft sensitive marine clay model formulations and comprehensive computational efforts are presented parametric study of site response analysis focusing on the effects of soil disturbance degree and depth on generic clay grounds with varying sloping angles subjected to harmonic and earthquake loadings are performed the predicted acceleration amplification maximum shear strains and permanent displacements provide insight of earthquake performance of submarine sensitive clay slopes the main findings are drawn based on several key concepts first undisturbed sensitive clay is typically stiffer and stronger than disturbed clay consolidated at the same stress level and hence unless strain softening is triggered structured sensitive clay will perform better than insensitive clay of the same residual strength second post peak softening at shallow depth will lead to strain localization on a thin layer which is the main cause of sudden change of upward wave propagation characteristics and large permanent displacement at seabed surface of mild submarine clay slope thirdly soil disturbance degrees and depths have very marked effects on seismic response and displacement performance of sensitive clay slopes and such effect will be further enhanced by slope angle or earthquake intensity which should be cautiously treated in engineering design

application of a characteristic periods based cpb approach to estimate earthquake induced displacements of landslides through dynamic numerical modelling the authors would like to thank the european union erdf for financial support via the monitorizacion sismica de deslizamientos criterios de reactivacion y alerta temprana project of the programa operativo feder de andalucia 2007 2013

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

lateral spreading within a limit equilibrium framework newmark s sliding blocks with degrading yield accelerations lateral spreading is a prevalent geotechnical problem associated with earthquake induced liquefaction often occurring at gentle slopes of loose saturated sand near bodies of water and causing sig

the interaction of seismic waves with step like slopes and its influence on landslide movements abstract the interaction of seismic waves with slopes is a major factor influencing landslide movements that involve slope stability local site seismic amplification and topographic effects affecting ground motion the results of a numerical study of landslide movements induced by the interaction of seismic waves with step like slopes are presented here to investigate this input slope interaction a dynamic analysis was performed using the finite difference stress strain numerical code flac 6 0 under visco plastic conditions the dynamic signals were selected to be representative of different peak ground accelerations pgas arias intensities and frequency contents and they were used in a parametric study of different step like slopes with different geometrical configurations in terms of dip height and thickness of geological strata the derived outputs were processed for a seismic amplification analysis and to evaluate the induced stress strain effects in terms of progressive failure and resulting displacements the obtained results i describe a fundamental role of topography in amplifying or de amplifying the seismic ground motion ii demonstrate that the progressive failure of unsheared slopes influences the seismic amplification iii show that the strain effects on unsheared slopes in terms of progressive failure are more intense with increasing arias intensity and slope dip iv prove that amplification or de amplification processes can justify the values of displacements involving pre existing landslide masses which are significantly different with respect to those expected on the basis of sliding block approaches i e newmark s and flexible sliding block methods v highlight that in the geological setting considered here the seismically induced displacements arising from the reactivation of pre existing landslide masses can be significantly underestimated by sliding block approaches in the case of low angle slopes characterised by high k values i e the ratios between the critical pseudostatic threshold ky of the landslide and pgas of the applied seismic input

a unified model for predicting earthquake induced sliding displacements of rigid and flexible slopes abstract permanent sliding displacement represents a common damage parameter for evaluating the seismic stability of slopes recently developed empirical models for the sliding displacement of shallow rigid sliding masses have demonstrated that including multiple ground motion parameters in the predictive model e g peak ground acceleration and peak ground velocity improves the displacement prediction and reduces it uncertainty a unified framework is developed that extends these empirical displacement models for application to flexible sliding masses where the dynamic response of the sliding mass is important this framework includes predicting the seismic loading for the sliding mass in terms of the maximum seismic coefficient kmax and the maximum velocity of the seismic coefficient time history k velmax the predictive models are a function of the peak ground acceleration pga peak ground velocity pgv the natural period of the sliding mass ts and the mean period of the earthquake motion tm the empirical predictive models for sliding displacement utilize kmax and k velmax in lieu pga and pgv and include a term related to the natural period of the sliding mass this unified framework provides a consistent approach for predicting the sliding displacement of rigid ts 0 and flexible ts 0 slopes

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

middle holocene climates and human population densities in the great basin western usa much of western north america saw higher temperatures and lower precipitation during the middle holocene the great basin became much drier and warmer than it is today causing major shifts in lake levels treelines plant community composition and vertebrate distributions and abundances to assess the impact of climate change on middle holocene human population densities in this region we examine the frequency structures of radiocarbon dated archaeological sites through time in three separate parts of the great basin the bonneville basin fort rock basin and western lahontan basin the results of the analysis support the hypothesis that human population densities in many parts of the great basin dropped substantially in response to middle holocene climate change but also document that there were intervals during the middle holocene in all three areas that appear to have been marked by temporary population increases we hypothesize that these increases were associated with equally temporary increases

simplified procedure for estimating earthquake induced deviatoric slope displacements a simplified semiempirical predictive relationship for estimating permanent displacements due to earthquake induced deviatoric deformations is presented it utilizes a nonlinear fully coupled stick slip sliding block model to capture the dynamic performance of an earth dam natural slope compacted earth fill or municipal solid waste landfill the primary source of uncertainty in assessing the likely performance of an earth waste system during an earthquake is the input ground motion hence a comprehensive database containing 688 recorded ground motions is used to compute seismic displacements a seismic displacement model is developed that captures the primary influence of the system s yield coefficient ky its initial fundamental period ts and the ground motion s spectral acceleration at a degraded period equal to 1 5 ts the model separates the probability of zero displacement i e 1 cm occurring from the distribution of nonzero displacement so that very low values of calculated

seismic displacement of gently sloping coastal and marine sediment under multidirectional earthquake loading abstract gentle sediment laden slopes are typical of the onshore coastal zone and offshore continental shelf and slope coastal sediment are commonly young weakly consolidated materials that are well stratified have low strength and can mobilize shear displacements at low levels of stress seismically driven plastic displacements of these sediment pose a hazard to coastal cities buried onshore utilities and offshore infrastructure like harbor protection and outfalls one dimensional rigid downslope directed newmark sliding block analyses have been used to predict earthquake deformations generally on steeper slopes that are modeled as frictional materials this study probes the effect of multidirectional earthquake motions on inertial displacements of gently sloping ground of the coastal and offshore condition where soft compliant soil is expected toward that objective this investigation seeks to understand the effect on newmark type displacements of 1 multidirectional earthquake shaking and 2 soil compliance in order to model multidirectional effects the earthquake motions are rotated into the local slope strike and dip components on gently sloping ground including the strike component of motion always results in a larger and more accurate shear stress vector strike motions are found to contribute to downslope deformations on any declivity compliant response of the soil mass also influences the plastic displacements the magnitude of seismic displacements can be estimated with a simplified model using only the estimated soil yield acceleration ky and the peak ground velocity vmax of the earthquake motions compliance effects can be effectively mapped using the concept of plastic displacement response spectra pdrs

temporal frequency distributions of alluvium in the american southwest taphonomic paleohydraulic and demographic implications abstract the use of radiocarbon frequency distributions to reconstruct prehistoric human and animal populations must account for taphonomic loss and other factors that affect the archaeological and paleontological records surovell et al jas 36 1715 1724 have recently proposed a correction for taphonomic bias that is based on the radiocarbon frequency of a global sample of volcanic deposits analysis of 717 radiocarbon dates sampled from the alluvium of the san pedro and santa cruz rivers and their tributaries in southeastern arizona shows that discovery and scientific biases also play an important role in the creation of radiocarbon frequency distributions and that the rate of taphonomic bias in prehistory is not predicted by the radiocarbon frequency of volcanic deposits the latter principle is further argued using a sample of 123 pliocene to clovis age proboscideans from the san pedro valley we propose an alternative model that is based on the nature of the stratigraphic record with discovery bias scientific bias taphonomic loss and the shape of the calibration curve all operating to influence the temporal frequency distribution of radiocarbon dated prehistoric phenomena

composite mechanism of the buyukcekmece turkey landslide as conditioning factor for earthquake induced mobility abstract earthquake induced displacements of landslides are significantly conditioned by their 1d and 2d interactions with seismic waves as currently proven by several studies nevertheless the role of a more complex geological setting responsible for a heterogeneous composition of the landslide mass can significantly influence these phenomena the heterogeneity can also depend on multiple phases of the landslide activity responsible for dislodging the whole landslide mass into submasses each one delimited by secondary scarps and characterized by individual mobility hence in the framework of the european project marsite marmara supersite new directions in seismic hazard assessment through focused earth observation in the marmara supersite the buyukcekmece landslide located approximately 30 km w of istanbul turkey was considered as a case study this landslide involves a large mass of approximately 140 million cubic metres composed of silty clays tuffs and sands ascribable to cenozoic geological formations the landslide is characterized by multiple phases of activity with a composite rototranslational mechanism which created seven submasses delimited by secondary scarps the scheme of water circulation in the landslide slope based on piezometer data as well as on a geological survey accounts for two flow nets the first shallower flow net is located in superficial sandy deposits outcropping in the dislodged landslide submasses the second deeper flow net is located in the main sliding surface a slope stability analysis following a global limit equilibrium approach provided a distribution of the pseudostatic coefficient vs pore water pressure the results show that the stability of the landslide submasses increases moving downslope and reactivations are expected in the case of earthquakes with a return period between 475 and 2475 yr according to the local seismic hazard dynamic numerical modelling was also performed using the stress strain finite difference code flac 7 0 to derive the distributions of horizontal displacements vs characteristic period ratios defined as the period due to depth ts and total length tl of the landslide mass over the earthquake characteristic period tm the obtained results indicate that an effective characteristic period of the landslide tl related to the length of a single counter slope tilted submass can provide a more correct explanation for the effect of seismic wave interactions on earthquake induced displacements this result indicates that the earthquake induced mobility of the buyukcekmece landslide is strongly conditioned by its composite rototranslational mechanisms in general these results indicate that landslide evolution can induce a change over time for the characteristic periods related to the dimensions of the dislodged landslide portions and then modify its interactions with seismic waves

what happened at 1500 1000 cal bp in central australia timing impact and archaeological signatures this paper reviews the late holocene archaeology of central australia the last 1500 years saw significant changes in the archaeological record in this part of the australian arid zone with shifts in settlement pattern site histories resource use tool inventories and rock art much of the evidence points to regional population growth beginning 1500 1000 cal bp and coinciding with expansion of summer rainfall grassland and more frequent palaeoflood events hunter gatherer groups appear to have increased their use of marginal or outlying areas as these became seasonally accessible responses to the demographic changes especially in the better watered ranges include more extended occupation of existing sites more processing of acacia and grass seeds and an increase in territoriality reflected in the greater differentiation of rock art complexes after 1500 cal bp the archaeological changes are not scaled commensurately with the modest environmental shifts at this time indicating that human enviro

shaking table modeling of seismically induced deformations in slopes physical model experiments were performed on a 1 g shaking table with the principal goals of 1 investigating the mechanisms of seismically induced permanent deformations in slopes and 2 assessing the accuracy and applicability of the newmark sliding block procedure for estimating seismically induced deformations in slopes each of the clayey slope models deformed in response to strong shaking with the principal mode of deformation being deep rotational translational sliding displacement deformations were principally focused along one or more highly localized shear surfaces though a significant amount of additional deformation was also distributed over a relatively wide region of the models the newmark analyses generally provided moderately accurate although somewhat unconservative estimates of deformations displacements computed using the rigid sliding block analysis ranged from 27 to 225 of maximum measured displacements and averaged about 75 of measured displacements for the test series the newmark type analyses were most reliable for those model tests that experienced large deformations where the sliding resistance was controlled principally by postpeak to residual strengths

residual shear strength variability as a primary control on movement of landslides reactivated by earthquake induced ground motion implications for coastal oregon u s most large seismogenic landslides are reactivations of preexisting landslides with basal shear zones in the residual strength condition residual shear strength often varies during rapid displacement but the response of residual shear zones to seismic loading is largely unknown we used a ring shear apparatus to perform simulated seismic loading tests constant displacement rate tests and tests during which shear stress was gradually varied on specimens from two landslides to improve understanding of coseismic landslide reactivation and to identify shear strength models valid for slow gravitational failure through rapid coseismic failure the landslides we studied represent many along the oregon u s coast seismic loading tests resulted in 1 catastrophic failure involving unbounded displacement when stresses represented those for the existing landslides and 2 limited to unbounded displacement when stresses represented those for hypothetical dormant landslides suggesting that coseismic landslide reactivation may be significant during future great earthquakes occurring near the oregon coast constant displacement rate tests indicated that shear strength decreased exponentially during the first few decimeters of displacement but increased logarithmically with increasing displacement rate when sheared at 0 001 cm s 1 or greater dynamic shear resistance estimated from shear strength models correlated well with stresses observed during seismic loading tests indicating that displacement rate and amount primarily controlled failure characteristics we developed a stress based approach to estimate coseismic landslide displacement that utilizes the variable shear strength model the approach produced results that compared favorably to observations made during seismic loading tests indicating its utility for application to landslides

effects of near fault ground shaking on sliding systems a numerical study is presented for a rigid block supported through a frictional contact surface on a horizontal or an inclined plane and subjected to horizontal or slope parallel excitation the latter is described with idealized pulses and near fault seismic records strongly influenced by forward directivity or fling step effects from northridge kobe kocaeli chi chi aegion in addition to the well known dependence of the resulting block slippage on variables such as the peak base velocity the peak base acceleration and the critical acceleration ratio our study has consistently and repeatedly revealed a profound sensitivity of both maximum and residual slippage 1 on the sequence and even the details of the pulses contained in the excitation and 2 on the direction or in which the shaking of the inclined plane is imposed by contrast the slippage is not affected to any measurable degree by even the strongest vertical components of the accelerograms moreover the slippage from a specific record may often be poorly correlated with its arias intensity these findings may contradict some of the prevailing beliefs that emanate from statistical correlation studies the upper bound sliding displacements from near fault excitations may substantially exceed the values obtained from some of the currently available design charts

nested newmark model to calculate the post earthquake profile of slopes abstract the newmark sliding block approach is a common means of evaluating permanent displacements of slopes undergoing seismic loading however the conventional newmark approach omits the presence of multiple shear zones or regions of dispersed shear movement the occurrence of these shear movements within slopes can often materialize with added vertical and lateral movements above the basal failure surface typically considered in the conventional newmark approach this study modifies the conventional newmark sliding block approach by discretizing a given slope into a series of nested critical failure wedges each with an associated yield acceleration termed a nested newmark model nnm use of the nnm enables assessment of a post earthquake slope profile within a limit equilibrium framework based on the integration of relative displacements from the toe to the crest the results demonstrate a different response than conventional newmark approaches the model outputs can account for the restriction of toe movements as well as heaving and slumping behavior of the slope face and crest respectively larger seismic excitation resulted in further destabilization of nested wedges near the crest the presented approach establishes a framework that can be extended to any type of failure geometry or series of failures including rotational geometry these results are compared to a numerical model which exhibit similar behavior this framework is conceptual but builds upon the well accepted newmark sliding block approach to provide an alternative means of assessing post earthquake slope movements

triggering mechanisms of slope instability and their relationship to earthquakes and tsunamis submarine and shoreline slope failures that accompany large earthquakes and large tsunamis are triggered by several mechanisms triggering mechanisms range from direct effects such as inertial forces from earthquake shaking to indirect effects such as rapid drawdown that occurs when an earthquake generated tsunami first approaches a shoreline soil shear strength also plays an important role in earthquake related slope failures earthquakes change the shear strength of the soil by inducing excess pore water pressures these excess pore water pressures change with time after the earthquake resulting in changes in shear strength and slope stability with time this paper reviews earthquake related triggering mechanisms for submarine and shoreline slope failures the variation in shear strength with time following an earthquake is examined and it is shown that delayed slope failures after an earthquake can occur as a result of changes in earthquake induced excess pore water pressures and shear strength with time

nonlinear coupled seismic sliding analysis of earth structures earthquake induced sliding displacements of earth structures are generally evaluated using simplified sliding block analyses that do not accurately model the seismic response of the sliding mass nor the seismic forces along the slide plane the decoupled approximation introduced to capture each of these effects separately is generally believed to be conservative however recent studies using linear viscoelastic sliding mass models have revealed instances where the decoupled approximation is unconservative in this paper a coupled analytical model that captures simultaneously the fully nonlinear response of the sliding mass necessary for intense motions and the nonlinear stick slip sliding response along the slide plane is presented the proposed sliding model is validated against shaking table experiments of deformable soil columns sliding down an inclined plane the effect of sliding on the response of earth structures is evaluated and comparisons are made between sliding displacements calculated us

reviewing human environment interactions in arid regions of southern south america during the past 3000 years abstract interactions between human societies and the environment that they inhabit have been a controversial topic in archaeology for at least the past fifty years currently modern theoretical approaches take this subject as a key issue in their research agenda this paper presents a review of the main outcomes of several archaeological and multidisciplinary south american projects related to this theme the case studies discussed here are all located within arid settings and can be grouped into three broad geographic areas puna or altiplano of northwestern argentina cuyo west central argentina and southern patagonia these regions cover a wide latitudinal range extending from 22 to 52 s they were selected for comparison due to environmental similarities and a common record of past climate impacts mainly related to the medieval climatic anomaly mca and the little ice age lia although the impacts of these climatic changes were locally heterogeneous in their intensity and the quality of the available information is regionally variable they provide a base line for comparison and supra regional integration the integration of archaeological and palaeoenvironmental data on this broad supra regional spatial scale allows us to identify interesting historical trajectories associated with particular time periods as an example there are some spatial rearrangements of large populations during the mca in the three areas additionally there are variable patterns in the changes associated with the different social contexts that impose specific demographic and economic constraints finally this study sets the basis for new questions and provides a guide to the methodological and theoretical issues that we need to address in order to answer them

sliding displacement of flexible earth slopes subject to near fault ground motions abstracta fully coupled simplified method that incorporates soil nonlinearity is used to conduct sliding block analysis of slopes subjected to near fault pulse like and nonpulse like ground motions the effects of the ground motion pulse on the computed sliding displacements are investigated and the efficiency of various ground motion intensity measures for predicting the sliding displacement of slopes is evaluated it is shown that the slope is expected to have larger displacements over shorter time intervals when near fault ground motions have pulse like characteristics results also indicate that for cases in which the natural period of a slope is close to the period of the pulse of a recorded ground motion an equivalent wavelet pulse appropriately represents the displacement response of slopes predictive models are developed for the sliding displacement of near fault ground motions using spectral acceleration and peak ground velocity as predictive variables in addition it is shown that for certai

on the applicability of available regression models for estimating newmark displacements for low to moderate magnitude earthquakes the case of the betic cordillera s spain abstract newmark displacement estimation is generally computed using empirical models these models are estimated from large datasets that mainly comprise moderate to high magnitude events mw 6 0 in this work we study the performance of several of these models to study moderate to low magnitude scenarios for this purpose data from the betic cordillera s spain with magnitudes ranging from mw 3 5 to 6 3 were used to compare with model predictions the results show that errors in the estimates depend on the magnitude of events or on the yielding acceleration considered to estimate the displacement the availability of an appropriate range of data magnitude and yielding acceleration when defining the regression model may overcome the differences due to specific characteristics of the seismotectonic context of the area where data derives from the results also show that performance of models including several ground motion predictors is better than those based on a single parameter regardless of the combination these predictors furthermore regression models with polynomial forms present a better performance than other functions based on the logarithm of these predictors finally new specific models for the betic cordillera are proposed especially suitable for low magnitude events

fully coupled dynamic analysis of an earth dam the paper studies the seismic behaviour of an existing homogeneous earth dam using a fully coupled finite element effective stress approach in conjunction with a recently developed multi surface elasto plastic constitutive model for structured soils the model is calibrated using laboratory test results for the embankment material and the foundation soils the initial state variables stress hardening parameters are determined by simulating a simplified geological history of the foundation soil dam construction stages and reservoir impounding prior to the application of the earthquake shaking at the bedrock level the paper critically reviews the role of the constitutive model parameters the hysteretic damping introduced by the model and the additional viscous damping parameters in the accumulation of permanent displacements and in the development and subsequent dissipation of excess pore water pressures due to the seismic loading the analyses carried out with reference to a set of earthquake reco

late holocene environmental dynamics in fluvial and aeolian depositional settings archaeological record variability at the lower basin of the colorado river argentina abstract this paper deals with the way in which the environmental dynamics that took place in the lower basin of the colorado river buenos aires province argentina have affected the degree of archaeological resolution integrity and site preservation in different sectors of the study area e g coastal fringe delta and interior dune fields evidence from geomorphologic stratigraphic and sedimentary analyses as well as chemical parameters and zooarchaeological assemblages are used in order to propose spatial and temporal variations in the structure of the archaeological record these lines of evidence were also used for inferring general paleoclimatic trends the results obtained indicate that the inland landforms that contained initial late holocene archaeological assemblages 3000 1000 14c bp have suffered important morphodynamic processes that produced site destruction loss of organic material and lower degrees of integrity and site resolution conversely landforms located near the delta and the coastal fringe underwent more stable geomorphic processes e g pedogenesis that promoted better preservation resolution and integrity during the initial late holocene and particularly during the final late holocene 1000 250 14c bp the recognition of this pattern is crucial in order to evaluate demographic processes linked with the intensity and mode of hunter gatherer occupation of the area and population dynamics throughout time

a multi block sliding approach to calculate the permanent seismic displacement of slopes abstract the newmark sliding block method is widely used to assess the seismic performance of earth slopes by calculating the permanent displacement of the simplified sliding mass the conventional newmark method models the potential landslide mass as a single rigid block sliding on a well defined slip surface in this study a multi block approach to calculate the sliding displacement of slopes is presented the dynamic equation of a series of rigid blocks in different sliding conditions is established and the complex interactions within the slip episodes of rigid block assemblies are explicitly resolved the results show that the original newmark single block method may produce unconservative estimates of permanent displacement of the shallow sliding mass when the deep seated sliding subsequently occurs during the earthquake the predicted displacement of the upper sliding mass which is simplified as a summation of the newmark displacement of each single sliding mass may either overestimate or underestimate the computed displacement including the coupling of sliding of multiple soil masses the developed approach extends the well accepted newmark sliding block method and can serve as an alternative to predict the seismic slope displacement in which multiple failure surfaces are expected during earthquakes

inclined plane studies of the newmark sliding block procedure this study considers the shaking induced displacement and dynamic response of a rigid block and deformable columns of soil on an inclined plane this work demonstrates that because of the coupled d

coupled analysis of earthquake induced permanent deformations at shallow and deep failure planes of slopes abstract the seismic performance of slopes is commonly evaluated by simplified sliding block analyses in this paper an extended sliding block model is developed to compute the earthquake induced deformations at both shallow and deep failure planes of slopes the coupled analytical model captures simultaneously the stick stick stick slip and slip slip behaviors of the lumped mass system of soil profile the complex interactions between the dynamic response of the soil and the slip episodes at shallow and deep slide planes are revealed the proposed sliding model is compared to the conventional single base sliding analyses and the influence of the presence of shallow failure sliding is emphasized then the dynamic response and permanent displacement of slopes with different locations of the shallow sliding plane and different yield accelerations of shallow and deep sliding planes are examined the comparisons are also performed for permanent displacements determined from the developed coupled multi sliding procedure and from the seismic sliding model with multiple rigid blocks finally an example is presented to demonstrate the procedure in the application and the differences of the results from the traditional coupled approach the coupled model in this study provides a rigorous procedure to combine the shallow and deep failure modes for the assessment of the co seismic landslide hazard

taphonomic evaluation of penguin spheniscidae remains at a shell midden on the northern coast of patagonia san matias gulf rio negro argentina abstract archaeological deposits in continental patagonia that allow an adequate discussion of the exploitation of seabirds particularly the spheniscidae are scarce in many cases characteristics of bone assemblages seem to indicate the natural incorporation of penguin bones into archaeological contexts this suggests it is not always possible to support the argument that the presence of penguin remains indicates a priori consumption by humans the bajada de los pescadores bp2 site san matias gulf rio negro patagonia argentina provides a case study that allows the origin of these deposits and their contents to be evaluated in terms of the exploitation of penguins and other marine resources by hunter gatherers during the late holocene this paper discusses the origin of the archaeological deposit its context and the agents involved in its formation the analysis used criteria formulated previously in the framework of actualistic taphonomic observations with the aim of assessing the integrity of this sample and evaluating its contribution towards clarifying the role of penguins in the subsistence of people on the northern patagonian coast

human responses to middle holocene altithermal climates on the north american great plains abstract the climate of the great plains during the middle holocene varied considerably but overall it was marked by a north south gradient of increasingly warmer and drier conditions with a reduction in effective moisture surface water and resource abundance and an increase in resource patchiness sediment weathering erosion and aeolian activity pronounced drought conditions were most evident on the southern high plains understanding the human responses to middle holocene climates is complicated by a lack of archaeological data which is partly a result of geomorphic processes that removed or deeply buried sites of this age and by the varying adaptive responses of hunter gatherers during this period on the southern high plains where drought was most severe surface and groundwater sources dried and bison populations were diminished prompting substantial adaptive changes including local abandonment well digging to tap underground water and a widening of the diet breadth to incorporate higher cost lower return seed and plant resources sites of this age on the central and northern plains also show a possible increase in diet breadth with the incorporation of plant foods in the diet and perhaps changes in settlement mobility including possible shift into higher elevation areas or mapping on to extant rivers and springs but linking those changes to middle holocene drought is less straightforward