effects of groundwater level on seismic response of soil foundation systems abstracta set of dynamic centrifuge experiments was performed to assess the effect of the depth of the groundwater table on the seismic site response and kinematic interaction of a foundation on un

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

the identification and significance of pure sediment derived granites the characterization of the geochemical reservoirs of the earth s continental crust including the determination of representative upper and lower crustal compositions underpins our understanding of crustal evolution the classic i and s type granite classification has often been invoked to distinguish between melts derived from igneous protoliths and those derived from the melting of a sedimentary source recent geochemical studies suggest that most granites even those cited as typical examples of s type show evidence for a mixture of mantle and upper crustal sources thereby implying that granite formation is evidence for overall crustal growth we have examined the source of leucogranite bodies in one of the world s youngest collisional orogens using novel zircon techniques that can resolve the presence of even minor mantle contributions 232 zircons from 12 granites from the bhutan himalaya were analysed by in situ techniques for o hf and u pb isotopic signatures in combination with data from the granite host rocks our data show that the himalayan leucogranites were derived solely from metamorphosed crustal sediments and do not record any mantle contribution this finding is consistent with the time lag between crustal thickening and widespread crustal melting and the heat producing capacities of the pelitic source rocks we conclude that himalayan leucogranites provide a more suitable type locality for s type granites than the lachlan area in south east australia where the term was first defined the himalayan leucogranites therefore provide evidence that syn orogenic melting during collisional events does not necessarily result in crustal growth importantly crustal growth models should not always assume that crustal growth is achieved during collisional orogenesis

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

heavy minerals and garnet geochemistry of stream sediments and bedrocks from the almklovdalen area western gneiss region sw norway implications for provenance analysis abstract detrital heavy minerals commonly document the geological setting in the source area hence they are widely used in sedimentary provenance analysis in heavy mineral studies the 63 125 and 63 250 m grain size fractions are most commonly used heavy mineral data and garnet geochemistry of stream sediments and bedrocks from the catchment area draining the almklovdalen peridotite massif in sw norway reveal that a wider grain size spectrum needs to be considered to avoid misleading interpretations the almklovdalen peridotite massif consists mainly of dunite and harzburgite as testified by the heavy mineral suite at the outlet of the main river the heavy mineral spectrum is very monotonous due to dilution by a strong influx of olivine heavy minerals like apatite and epidote characterising the host gneisses have almost disappeared mgo rich almandine garnets are more frequent in the coarser grain size fractions whereas mno rich almandine garnets are more frequent in the finer grain size fractions garnets with pyrope content exceeding 50 are only found in the 500 1000 m grain size fraction therefore the sample location and the selected grain size fraction are of paramount importance when dealing with heavy minerals and mineral geochemical data otherwise provenance sensitive information may be missed

effect of site condition below slip surface on prediction of equivalent seismic loading parameters and sliding displacement abstract the effect of seismic site response below the slip surface is commonly ignored in conventional predictive models of sliding displacement of slopes in this study the influence of site condition below the critical slip surface i e the bedrock depth below slip surface on the dynamic response of sliding mass and the seismic sliding displacement is investigated the equivalent seismic loading time history which represents the average acceleration within the sliding mass is derived for sliding masses with different site conditions i e various depths to the overlying bedrock the frequency dependent effects of bedrock depth are emphasized for accurate assessment of the stability of slopes during earthquakes for the same sliding mass the equivalent seismic loading parameters and sliding displacements are strongly dependent on the depth to the underlying bedrock empirical models are developed for predicting the amplitude and frequency parameters of equivalent seismic loading by introducing the ratio of the depth of sliding mass and bedrock to capture the seismic responses of the sliding mass as well as the full slope site the performance of existing empirical models for rigid block sliding displacement is examined and simplified modifications are performed to appropriately predict the sliding displacement by including the dynamic response of sites two example applications are presented and the results indicate that the proposed empirical models including the site condition below the slip surface provide a more accurate assessment of dynamic response and sliding displacement of slopes

comparison of strong ground motion recordings of the lushan china earthquake of 20 april 2013 with the next generation attenuation nga west2 ground motion models abstract a total of 39 free field accelerograms in the 2013 m w 6 7 lushan earthquake with the closest site to rupture distances r rup being less than 200 km are compared with the median ground motions predicted by the recent next generation attenuation nga west2 ground motion prediction equations gmpes overall for most lushan station recordings over the whole range of r rup the spectral acceleration sa of the peak ground acceleration pga and of t 0 06 s are within one standard deviation of the predictions from the five nga west2 gmpes most intraevent residuals also fall between plus and minus one standard deviation from the predictions moreover the standard deviation of intraevent residuals are smaller for sa of t 0 06 s than for pga which suggests that the application of nga west2 in predicting high frequency ground motion due to the lushan earthquake is acceptable the spatial contours of intraevent residuals for pga predicted by the five nga west2 models are almost the same all showing four regions of negative intraevent residuals three of these regions are mainly distributed with the source to site azimuth approximating to 90 or 90 and the other one approximating to 180 which are consistent with the extrusion and rupture directions of the lushan earthquake fault in general the five nga west2 gmpes generate relatively large intraevent residuals at the long period t 1 0 s for r rup exceeding 100 km although the intraevent residuals are not as large the short period hanging wall effects are more consistent with the nga west2 hanging wall scaling than those of long period and the short period ground motions on the footwall are more consistent with the nga west2 models than those on the hanging wall

simplified methodology for consideration of two dimensional dynamic response of levees in liquefaction triggering evaluation abstractlevees are very challenging engineering structures to study in part because they are not typically well engineered structures unfortunately there is little to no guidance as to how to evaluate the seismic vulnerability of levees this study focuses on systematically studying the dynamic response of levees using a wide range of input ground motions and developing a simplified procedure for the liquefaction triggering evaluation of earthen levees accounting for the dynamic response of the levee the study was based on three levee sites representative of three select california central valley regions however because floodplains tend to generally have similar depositional environments the study can be extended to other regions as long as some of the principal characteristics are still applicable a wide range of input ground motions was used to capture and assess the variability in response and performance because of multiple possible earthquake scenarios two aspects of the dynamic response an

comparison of the recorded frequency content parameters of the 2013 lushan earthquake with empirical model predictionscomparison of the recorded frequency content parameters of the 2013 lushan earthquake

an interpretation of the seismic behaviour of reinforced earth retaining structures this paper provides an interpretation of the behaviour of retaining structures made of geosynthetic reinforced earth subjected to a severe seismic loading it is seen that during strong ground motion the main source of energy dissipation derives from the transient activation of plastic mechanisms within the soil mass these mechanisms can be global local or a combination of the two using numerical pseudo static analyses and limit analysis methods it is shown that three retaining structures having a similar overall seismic resistance expressed by their critical seismic coefficient activate different global local or combined plastic mechanisms the seismic performance of the different retaining structures is then evaluated through a series of dynamic analyses in which acceleration time histories are imposed to the bottom boundary of the same numerical models used for the pseudo static analyses the results of the dynamic analyses are interpreted in the light of the plastic mechanisms evaluated w

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

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

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

the influence of frequency and duration of seismic ground motion on the size of triggered landslides a regional view abstract observation theory and intuition all suggest that larger earthquakes should trigger larger landslides many factors could contribute to this including depth dependent shear strength or non linearity of ground motion in soils and rock but we hypothesize that the key characteristics of large earthquakes causing this phenomenon are in addition to magnitude the frequency and duration of the strong ground motion because of the paucity of site specific data for detailed analysis we take a regional approach to this question by analyzing strong motion records and earthquake induced landslide eqil inventories from six well documented earthquakes ground motion is characterized using earthquake magnitude and the median durations and frequencies mean periods of subsets of strong motion records relevant to landslide triggering eqil inventories are characterized using the median landslide area of the entire inventory as well as the median areas of the largest 1 of the landslides and the largest 10 landslides we then compare ground motion characteristics with landslide size statistics to determine possible correlations comparisons of all earthquake and landslide size statistics show strong positive correlations between landslide size and 1 magnitude 2 ground motion duration and 3 mean period although all the ground motion measures yield highly correlated regressions mean period appears to be the best overall predictor of landslide size landslide modeling using newmark s sliding block method also shows that longer mean periods and durations and larger magnitudes correlate strongly with increases in modeled displacements these results support our hypothesis that increasing period and duration of seismic ground motion are the physical factors driving increased landslide sizes for larger earthquakes additional studies including data from a much larger set of earthquakes is needed to confirm the results of this initial study

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

effect of sediment column on weak motion site response for a deep basin fill unique challenges arise when projecting dynamic site response in a deep steep sided irregularly shaped sediment filled basin the influence of shallow sediments on site response was investigated for a 1 km deep alluvial column in the las vegas basin subjected to weak ground motions a one dimensional equivalent linear model was applied response analyses for deep deposits are complicated because dynamic material properties at depth are uncertain to compensate the model half space was placed well above the physical bottom of the sediment column the depth to half space was selected by matching characteristics of projected surface response to measured data or expectations weak ground motion datasets resulting from underground nuclear tests were considered the best match half space depth 375 m greatly exceeded the depth of the threshold shear wave velocity for engineering bedrock the analysis captured site response over the period range 0 3 1 3 s when the parameterization was tested for a weak

a new seismic site coefficient model based on conditions in the south carolina coastal plain abstract a new seismic site coefficient model is developed in this article from the results of over 48 000 total stress 1d equivalent linear and nonlinear ground response simulations assuming conditions at seven locations in the south carolina coastal plain site coefficients f computed from the simulations are plotted versus average shear wave velocity in the top 30 m v s 30 and grouped by location spectral acceleration and spectral period in all plots it can be seen that f increases from zero to a zone of peak values as v s 30 increases from zero and then f decreases to a value of 1 as v s 30 approaches the reference soft rock value variables found to be most influential on f in addition to v s 30 and spectral acceleration are stiffness of material in the top 100 m depth to top of rock and frequency content of the rock outcrop motion a mathematical model for median values of f defined by these five variables is proposed significant differences exist between the new seismic site coefficient model and the site coefficients commonly assumed in current seismic design codes particularly where v s 30 is

deep subduction of felsic rocks hosting uhp lenses in the central saxonian erzgebirge implications for uhp terrane exhumation abstract contrasting metamorphic conditions determined by chemical geothermobarometric investigations of ultrahigh pressure uhp lenses surrounded by high pressure hp and medium pressure mp felsic country rocks are an enigmatic feature of uhp terranes one of the major questions arising is whether the uhp lenses and the country rocks are a product of different peak metamorphic conditions corresponding to different maximum depth or whether country rocks also experienced uhp conditions but equilibrated and or re equilibrated at a different metamorphic stage here we address this question to the central saxonian erzgebirge in the northwestern bohemian massif germany in order to screen the variety of garnet from lithologies occurring in the study area we analyzed the detrital garnet record from seven modern stream sands in addition to 700 inclusion bearing garnet grains previously studied from the 125 250 m grain size fraction we analyzed the 63 125 and 250 500 m fractions and extended the dataset to overall 2100 inclusion bearing grains the new findings of coesite and diamond inclusions in several garnet grains which are in compositional contrast to garnet of the known uhp lenses but match with those of the felsic country rocks show that considerable parts of the country rocks underwent uhp metamorphism melt inclusions containing cristobalite kokchetavite and kumdykolite in garnet derived from the country rocks point to partial melting and re equilibration during exhumation at hp ht conditions although an amalgamation of rocks which reached different maximum depth may be responsible for some of the contrasting peak metamorphic conditions the mineralogical evidence for uhp conditions in the felsic country rocks surrounding the uhp lenses proves a largely coherent slab subducted to uhp conditions furthermore the presence of coesite in the subducting voluminous felsic crust and its transformation to quartz during exhumation have great implications for buoyancy development during the metamorphic cycle which may explain the high exhumation rates of uhp terranes

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

widespread landslides induced by the mw 5 1 earthquake of 11 may 2011 in lorca se spain abstract on 11 may 2011 a moderate magnitude mw 5 1 earthquake struck the city of lorca se spain and nearby areas causing notable damage injuries and fatalities field inspection of the area affected allowed the location and characterization of more than 250 induced landslides mainly of disrupted type rock soil falls disrupted soil slides and rock avalanches this number was very high when compared with the inventories of previous events of similar magnitude mw 4 7 to 5 0 in the zone and with the results of previous models for predicting slope behavior during earthquakes several factors are proposed here to explain the observed differences i the comparatively high magnitude mw 4 5 of a foreshock of the seismic series that may have weakened the slopes ii the high peak ground motion values recorded for these events and iii the occurrence of topographic site effects the results of this study point out the importance of including such effects as improvements in the models for studying the regional behavior of slopes

the lycian sarcophagus of arttumpara pinara turkey testing seismogenic and anthropogenic damage scenarios abstract a lycian sarcophagus located in the ancient city of pinara southwest turkey shows a clockwise rotation of 6 37 with respect to its north south oriented foundation considering the seismotectonic potential of the area this rotation has been attributed to earthquake ground motion before we present a 3d model of the sarcophagus based on 11 5 million points from a 3d laser scan the sarcophagus shows a crater in the eastern side of the coffin which was most probably caused by the detonation of an explosive charge during looting as the direction of the rotation agrees with the sense of motion expected from a blast we will attempt to quantify whether the rotation has a natural seismogenic or anthropogenic cause with a rigid block model we studied the feasibility of an explosion or earthquake ground motion as the reason for the rotation of the coffin scaled recorded ground motions from local earthquakes and a strong motion record from the recent l aquila italy earthquake m w 6 3 were used to study the sarcophagus dynamic reactions the calculations show that the geometry of the structure requires large peak ground acceleration amplitudes to initiate rocking above 4 m s 2 this rocking in turn is necessary to produce rotation around the vertical axis by translational movements the size of the explosion is back calculated from the crater size and compared with duration and amplitude of an impulse necessary to rotate the coffin the small rotations resulting from all earthquake simulations and the plausible explosion size necessary to rotate the coffin by the observed amount make an explosion a much more probable cause for the rotation of the sarcophagus than an earthquake

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

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

seismic compression of two compacted earth fills shaken by the 1994 northridge earthquake seismic compression is defined as the accrual of contractive volumetric strain in unsaturated soil during strong shaking by earthquakes we document and analyze two case histories denoted school site and site a of ground deformation from seismic compression in canyon fills strongly shaken by the northridge earthquake site a had ground settlements up to about 18 cm which damaged a structure while the school site had settlements up to about 6 cm for each site we perform decoupled analyses of shear and volumetric strain shear strain is calculated using one dimensional and two dimensional ground response analyses while volumetric strain is evaluated from shear strain using material specific models derived from simple shear laboratory testing that incorporates important effects of fines content and as compacted density and saturation analyses are repeated using a logic tree approach in which weights are assigned to multiple possible realizations of uncertain model parameters at the school site predicted settlements appear to be unbiased at site a the analyses successfully predict the shape of the settlement profile along a section but the weighted average predictions are biased slightly too low we speculate that the apparent site a bias can be explained by limited resolution of the site stratigraphy bias in laboratory derived volumetric strain models and or uncertainty in the estimated earthquake induced settlements