the role of perched aquifers in hydrological connectivity and biogeochemical processes in vernal pool landscapes central valley california relatively little is known about the role of perched aquifers in hydrological biogeochemical and biological processes of vernal pool landscapes the objectives of this study are to introduce a perched aquifer concept for vernal pool formation and maintenance and to examine the resulting hydrological and biogeochemical phenomena in a representative catchment with three vernal pools connected to one another and to a seasonal stream by swales a combined hydrometric and geochemical approach was used annual rainfall infiltrated but perched on a claypan duripan and this perched groundwater flowed downgradient toward the seasonal stream the upper layer of soil above the claypan duripan is 0 6 m in thickness in the uplands and 0 1 m in thickness in the vernal pools some groundwater flowed through the vernal pools when heads in the perched aquifer exceeded 0 1 m above the claypan duripan perched groundwater discharge accounted for 30 60 of the inflow to the vernal pools during and immediately following storm events however most perched groundwater flowed under or around the vernal pools or was recharged by annual rainfall downgradient of the vernal pools most of the perched groundwater was discharged to the outlet swale immediately upgradient of the seasonal stream and most water discharging from the outlet swale to the seasonal stream was perched groundwater that had not flowed through the vernal pools therefore nitrate nitrogen concentrations were lower e g 0 17 to 0 39 mg l 1 and dissolved organic carbon concentrations were higher e g 5 97 to 3 24 mg l 1 in vernal pool water than in outlet swale water discharging to the seasonal stream though the uplands vernal pools and seasonal stream are part of a single surface water and perched groundwater system the vernal pools apparently play a limited role in controlling landscape scale water quality copyright 2005 john wiley sons ltd

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

seasonal diurnal and storm scale hydrochemical variations of typical epikarst springs in subtropical karst areas of sw china soil co2 and dilution effects summary two year continuous ph conductivity temperature and water stage of the two typical epikarst springs nongla spring and maolan spring about 200 km apart in subtropical karst areas of sw china were presented our primary study objective was to understand how karst systems respond hydrochemically to recharge at different time scales and what the biogeochemical processes and controlling factors in the sw china epikarst environment are a thermodynamic model was used to link the continuous data to monthly water quality data allowing the calculation of co 2 partial pressures and calcite dolomite saturation levels on a continuous basis marked seasonal diurnal and storm scale variations were observed for ph conductivity co 2 partial pressures and calcite dolomite saturation indexes of the springs indicating that both springs are dynamic and variable systems however the coefficients of variation of these hydrogeochemical features tends to be in the order of seasonal storm scale diurnal the seasonal and diurnal variations of these features higher conductivity and lower ph in summer and at daytime lower conductivity and higher ph in winter and at nighttime tend to co vary with temperature which influences the production of co 2 in soils thus being the driving force for the variations soil co 2 effect the storm scale fluctuations occur during the spring summer rainy days due to the storm events depending on the rainfall intensities however there are differences in magnitudes and direction of the variations of these features at very high rainfall intensity the dilution effect dominates the variations characterized by the decrease in both conductivity and calcite dolomite saturation of the springs while soil co 2 effect determines the variations at lower rainfall intensity characterized by increase in co 2 partial pressure and conductivity but decrease in ph and calcite dolomite saturation in a word the hydrodynamic aspects together with hydrobiogeochemical characteristics need to be taken into account to correctly explain the hydrochemical variations of the epikarst springs results from the study demonstrate the need to redesign hydrogeochemical sampling strategies for epikarst springs in karst areas with monsoon climate like sw china i e with remarkable seasonal matching fluctuations in temperature rainfall and vegetation

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

evidence for a buried fault system in the coastal plain of the carolinas and virginia implications for neotectonics in the southeastern united states geomorphic geologic and geophysical data suggest the presence of an 600 km long north northeast trending buried fault system in the coastal plain of the carolinas and virginia herein named the east coast fault system the east coast fault system is expressed by anomalous changes in fluvial geomorphology that locally coincide with one or more of the following features linear aeromagnetic anomalies buried faults interpreted from seismic reflection data surface faults offsetting pliocene pleistocene surficial units locally brecciated phyllites and argillites gently upwarped sediments topographic highs and seismicity near summerville south carolina river anomalies where the rivers traverse unconsolidated upper pleistocene holocene flood plain sediments are evidence of deformation along the east coast fault system during the past 130 to 10 k y which may be ongoing the fault system traverses the epicentral area of the 1886 charleston south carolina earthquake and lies west of paleoliquefaction sites along the outer south carolina coastal plain thus the fault system could be the source of the charleston earthquake and other large prehistoric earthquakes therefore confirmation and demarcation of the east coast fault system and elucidation of its history will help better assess seismic hazards in the southeastern united states

displacement based seismic design of a shallow strip footing positioned near the edge of a rock slope abstract this paper presents a displacement based dynamic design of shallow strip footings located close to the edge of homogeneous and isotropic rock slopes the analysis is conducted using the generalized tangential technique in which the hoek brown strength is replaced by an optimal tangential mohr coulomb domain within the framework of the kinematic approach of limit analysis theory in order to better understand the influence of these factors including geometrical features rock strength parameters and seismic loading a parametric study is carried out an expression is derived and used to obtain a least upper bound solution for the bearing capacity of a footing on a rock slope considering a kinematically admissible log spiral failure mechanism in addition a similar expression of the horizontal yield seismic coefficient is derived for a given load acting on the foundation the assessment of earthquake induced permanent displacement is performed by a simplified procedure this requires the knowledge of a ground motion parameter that can be evaluated by site specific seismic hazard analyses or ground motion prediction equations and that considers the actual sliding surface the calculated displacement should not be greater than a selected limiting tolerable displacement for the specific case an example is presented illustrating the application of the design procedure for the bridge foundations

recurrence rates of large earthquakes in the south carolina coastal plain based on paleoliquefaction data we present a reanalysis of results of 15 years of paleoliquefaction investigations in the south carolina coastal plain all earlier radiocarbon age data and locations of organic material collected by various investigators were reviewed and recalibrated to obtain a uniform data set the calibrated dates and the spatial extent of the sandblows having similar dates were used to estimate ages and magnitudes of prehistoric earthquake episodes the results of this analysis suggest seven episodes episodes a g of prehistoric liquefaction in the past 6000 years and two possible scenarios for their occurrence in the first scenario three seismic sources exist within the coastal plain of south carolina at charleston a b e and g with magnitudes m 71 georgetown c and f and bluffton d with magnitudes m 6 in the second scenario episodes c and d are combined into one episode episode c9 in this scenario all earthquakes occurred at charleston and with m 71 episodes a and b seem to be more representative of the earthquake cycle and suggest a recurrence time of 500 600 years for m 71 earthquakes at charleston the recurrence times and magnitudes for episodes c and d are estimated at 2000 years and 6 0 respectively the older episodes are less frequent a fact that may be attributable to times of low ground water table before 6000 years b p the ground water table was too low to permit observable liquefaction features to develop at the surface

assessment of liquefaction hazards in charleston quadrangle south carolina abstract in this paper an improved method for evaluation of liquefaction hazard is presented the liquefaction potential index developed by iwasaki and his co workers is modified using the concept of probability the modified liquefaction potential index is then calibrated with field observation data which yields an empirical equation for the probability of liquefaction induced ground failure the method and procedure is then employed to study the ground shaking level of the 1886 charleston south carolina earthquake based on an analysis of liquefaction hazard in the charleston peninsula the results show that the ground shaking level of the 1886 event may be represented with moment magnitude mw 6 9 and peak ground surface acceleration amax 0 2 g finally the liquefaction hazard in the charleston quadrangle is evaluated and mapped using the ground motion that corresponds to the 475 year return period details of this assessment including limitation of the results are presented

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

index properties based criteria for liquefaction susceptibility of clayey soils a critical assessment the cooper marl in charleston s c a deep layer of clayey soils approximately 5 21 m below the ground surface is generally recognized as nonliquefiable material data from field cone penetration tests and laboratory tests of samples taken from the cooper marl are used to investigate the adequacy of index properties based criteria for assessing liquefaction susceptibility of clayey soils in particular the criterion based on soil behavior type index ic and that based on atterberg limits are examined the results show that the atterberg limits based criterion adequately reflected the characteristics of the marl whereas the ic based criterion erroneously identified the marl as being liquefiable a possible reason for the deficiency of ic and a modification to overcome this deficiency are presented

magnitudes and locations of the 1811 1812 new madrid missouri and the 1886 charleston south carolina earthquakes we estimate locations and moment magnitudes m and their uncertainties for the three largest events in the 1811 1812 sequence near new madrid missouri and for the 1 september 1886 event near charleston south carolina the intensity magnitude m i our preferred estimate of m is 7 6 for the 16 december 1811 event that occurred in the new madrid seismic zone nmsz on the bootheel lineament or on the blytheville seismic zone m i is 7 5 for the 23 january 1812 event for a location on the new madrid north zone of the nmsz and 7 8 for the 7 february 1812 event that occurred on the reelfoot blind thrust of the nmsz our preferred locations for these events are located on those nmsz segments preferred by johnston and schweig 1996 our estimates of m are 0 1 0 4 m units less than those of johnston 1996b and 0 3 0 5 m units greater than those of hough et al 2000 m i is 6 9 for the 1 september 1886 event for a location at the summerville middleton place cluster of recent small earthquakes located about 30 km northwest of charleston

ground motion and liquefaction simulation of the 1886 charleston south carolina earthquake as part of a comprehensive earthquake loss and vulnerability evaluation of the state of south carolina ground motions were simulated for a moment magnitude m 7 3 1886 charleston like earthquake using finite fault and point source stochastic numerical modeling the probability for liquefaction was also predicted based on factors of safety computed from average cyclic stress and shear wave velocity based cyclic resistance ratios clay content and saturation because there is considerable uncertainty regarding the 1886 source the rupture plane of the 1886 event was modeled as both a 100 km long 20 km wide fault static stress drop of 27 bars and a 50 km long 16 km wide fault 107 bar stress drop the source was assumed to be a north northeast striking strike slip fault coincident with the woodstock fault based on comparing the computed and observed 1886 liquefaction areas and ground motions for both the low and high stress drop events the two cases were weighted 0 8 and 0 2 respectively to accommodate epistemic uncertainty in eastern u s earthquake source processes three region specific point source attenuation models were also developed and used a single corner frequency model with both a constant stress drop and a magnitude dependent stress drop and the double corner frequency model the finite fault and point source models were weighted 0 8 and 0 2 respectively to incorporate site effects into the ground motion estimates an extensive effort was made to characterize the thicknesses shear wave velocities v s and dynamic material properties of unconsolidated sediments characteristic v s profiles were developed using the available subsurface information which incorporated a wide range of soil and rock conditions amplification factors were computed for four site response categories each of which were a function of soil thickness input hard rock motion and spectral frequency from the five weighted stochastic ground motion models two finite fault and three point source and amplification factors rock and soil ground motions were computed to produce statewide ground motion maps for the m 7 3 scenario event weighting of the charleston source and ground motion models was implemented so that the resulting liquefaction areas matched the 1886 areas of liquefaction peak horizontal ground acceleration pga values as high as 0 6 g 0 7 g were estimated in the vicinity of the modeled rupture pgas in the range of 0 3 g 0 4 g were estimated for charleston consistent with the observed building damage and liquefaction significant ground shaking pga 0 2 g extends out to distances of 50 60 km strong long period 1 0 sec ground motions are predicted throughout the state the probabilities for liquefaction were highest in the epicentral region 50 consistent with the observed occurrences of liquefaction in 1886 manuscript received 5 february 2003

nitrogen in rock occurrences and biogeochemical implications 1 there is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations nitrogen bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification nitrogen in rock originates as organically bound nitrogen associated with sediment or in thermal waters representing a mixture of sedimentary mantle and meteoric sources of nitrogen rock nitrogen concentrations range from trace levels 200 mg n kg 1 in granites to ecologically significant concentrations exceeding 1000 mg n kg 1 in some sedimentary and metasedimentary rocks nitrate deposits accumulated in arid and semi arid regions are also a large potential pool nitrogen in rock has a potentially significant impact on localized nitrogen cycles elevated nitrogen concentrations in water and soil have been attributed to weathering of bedrock nitrogen in some environments nitrogen released from bedrock may contribute to nitrogen saturation of terrestrial ecosystems more nitrogen available than required by biota nitrogen saturation results in leaching of nitrate to surface and groundwaters and where soils are formed from ammonium rich bedrock the oxidation of ammonium to nitrate may result in soil acidification inhibiting revegetation in certain ecosystems collectively studies presented in this article reveal that geologic nitrogen may be a large and reactive pool with potential for amplification of human impacts on nitrogen cycling in terrestrial and aquatic ecosystems

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

liquefaction potential map of charleston south carolina based on the 1886 earthquake a liquefaction potential map of the peninsula of charleston s c is presented in this paper liquefaction potential is expressed in terms of the liquefaction potential index developed by iwasaki et al and calculated using 44 cone penetration test profiles the cone profiles are supplemented with information from the 1 24 000 scale geologic map by weems and lemon several first hand accounts of liquefaction and ground deformation that occurred during the 1886 charleston earthquake and liquefaction probabilities determined by elton and hadj hamou based on standard penetration tests nearly all of the cases of liquefaction and ground deformation occurred in the holocene to late pleistocene beach deposits that flank the higher ground sediments of the wando formation to match the observed field behavior a deposit resistance correction factor of 1 8 is applied to cyclic resistance ratios calculated for the 100 000 year old wando formation no corrections are needed for the younger deposits in additional to 1886 field behavior the deposit resistance corrections are supported by ratios of measured to predicted shear wave velocity

nitrogen release from rock and soil under simulated field conditions abstract a laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate two rock types containing nitrogen slate 1370 mg n kg 1 and greenstone 480 mg n kg 1 were used along with saprolite and bc horizon sand from soils derived from these rock types the fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season nitrogen was released from rock and soil materials at rates between 10 20 and 10 19 mol n cm 2 s 1 results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the bc horizon of both soils concentrations of mineral nitrogen no 3 nh 4 in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching this seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a kcl solution estimates based on these laboratory release rates bracket stream water no 3 n fluxes and changes in the available mineral nitrogen pool over the active leaching period these results confirm that geologic nitrogen when present may be a large and reactive pool that may contribute as a non point source of nitrate contamination to surface and ground waters

why the new madrid earthquakes are m 7 8 and the charleston earthquake is m 7 estimates of magnitudes of large historical earthquakes are an essential input to and can seriously affect seismic hazard estimates the earthquake intensity observations modified mercalli intensities mmi and assigned magnitudes m of the 1811 1812 new madrid events have been reinterpreted several times in the last decade and have been a source of controversy in making seismic hazard estimates in the central united states observations support the concept that the larger the earthquake the greater the maximum felt distance for the same crustal attenuation and local soil conditions magnitude should be the main influence on intensity values at large distances we apply this concept by comparing the mean mmi at distances of 600 1200 km for each of the four largest new madrid 1811 1812 earthquakes the 1886 charleston south carolina earthquake the 1929 m 7 2 grand banks earthquake and the 2001 m 7 6 bhuj india earthquake we fit the intensity observations using the form mmi a c dist 0 8 log dist to better define intensity attenuation in eastern north america ena the intensity attenuation in cratonic india differs from ena and is corrected to ena using both the above estimate and published intensity relations we evaluate source marine geophysical q and stress drop information as well as a 1929 milne shaw record at chicago to confirm that the 1929 grand banks earthquake occurred in ena crust our direct comparison of mean intensities beyond 600 km suggests m 7 5 7 3 7 7 and 6 9 for the three new madrid 1811 1812 mainshocks and the largest aftershock and m 7 0 for the 1886 charleston south carolina earthquake with an estimated uncertainty of 0 3 units at the 95 confidence level based on a monte carlo analysis our mean new madrid and charleston mainshock magnitudes are similar to those of bakun and hopper 2004 and are much higher than those of hough and page 2011 for new madrid online material tables of mean modified mercalli intensity for 800 1200 and 600 1000 km distance ranges and figures of least squares fit for all intensity measures used and for frequency dependent q in easternmost canada

geomechanical characterisation of rock masses in alpine regions the basque arc basque cantabrian basin northern spain the geomechanical characterisation of rock masses in alpine regions is one of the main challenges currently facing rock mechanics these rock masses made up of very different materials and frequently tectonically disturbed are affected by engineering works giving rise to potentially important problems thus in the basque country these materials are at the cause of important fatalities occurring in recent years in this context we aim at characterising these materials with the ultimate purpose of predicting their behaviour the characterisation is initially approached based on the gsi mi and ci parameters following the hoek brown failure criterion this information is supplemented with field and laboratory measurements and by obtaining the rqd and rmr indices using the information obtained from 99 metering stations we develop a graphic classification procedure which allows us to distinguish materials based on their characteristics behaviour type and degree of associated problems and type and effectiveness of solutions provided eight classes of material are established

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

geologic nitrogen in terrestrial biogeochemical cycling recent research implicates geologic nitrogen as a large and reactive pool of nitrogen that can have significant ecological effects this study was conducted to determine the landscape distribution of geologic nitrogen and the fate of this nitrogen during rock to soil transformation in the lower mokelumne river watershed located in the western sierra nevada of california mineralogy and chemistry were determined for six major lithologies in the study area to examine the spatial distribution of nitrogen in bedrock in addition soil samples were collected from two watersheds having high stream water nitrate concentrations to determine the fate of nitrogen during weathering and soil formation with the exception of diorite all bedrock contained detectable concentrations of nitrogen 153 1801 and 98 739 mg n kg 1 for metasedimentary and metavolcanic lithologies respectively a significant amount of nitrogen was released during soil formation 2350 and 2570 kg n ha 1 for soils formed on greenstone and slate respectively this amount of nitrogen represents from 30 to 50 of the current soil nitrogen pool in these ecosystems nitrogen released from bedrock contributes to an excess of available nitrogen relative to biotic demands leading to nitrate leaching and elevated concentrations of nitrate in stream water given the widespread occurrence of geologic nitrogen and the large global inventory of nitrogen contained within bedrock the role of geologic nitrogen as a source of nitrogen for terrestrial biogeochemical cycling must be considered

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

seismic bearing capacity of a strip footing on rock slopes most of the seismic calculations currently used for the evaluation of seismic bearing capacity are formulated in terms of a linear mohr coulomb failure criterion however experimental evidence sho

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

seismic and static 3d stability of two stage rock slope based on hoek brown failure criterion two stage slope is beneficial to improve slope stability in comparison with single stage slope based on nonlinear hoek brown criterion a three dimensional failure mechanism is employed to estimate the stability of two stage rock slope with the effect of seismic inertia force being taken into account a generalized tangential technique is used to formulate the stability factor problem as a classical optimization problem corresponding to the dissipated energy the upper bound solutions are obtained by minimizing the objective function with respect to the location of sliding body center and the location of tangency point the seismic inertia force is considered and incorporated into the objective function in comparison with previously published solutions using the linear mohr coulomb criterion the validity of the present solutions is shown the analytical expressions for two stage slope are derived to estimate the seismic stability of slopes numerical results for different types of rocks are presented

solution of the ultimate bearing capacity at the tip of a pile in inclined rocks based on the hoek brown criterion abstract to investigate the bearing mechanism of piles in inclined slope this paper proposed an analytical method through geometric transformation to calculate the ultimate bearing capacity at the tip of a pile in inclined rocks based on the characteristic line method it was found that there were five failure modes for piles in inclined rocks depending on the embedment ratios slope angles average overburden load and tensile strength parameter of the rock mass when the pile failure mode was under the modes of deep pile with minor overburden dl and deep pile with major overburden dh the ultimate bearing capacity had no change as the slope angle and the pile embedment ratio changed when the pile was under the failure modes of semi deep pile with minor overburden sl semi deep pile with major overburden sh or shallow pile ss the ultimate bearing capacity decreased with an increasing rate as the slope angles increased and to get the same ultimate bearing capacity at the pile tip the pile embedment ratio should increase the proposed analytical method can be served as an efficient method to estimate the bearing capacity of piles in inclined slope with small slope angle typically less than 40

scenario liquefaction hazard maps of santa clara valley northern california maps showing the probability of surface manifestations of liquefaction in the northern santa clara valley were prepared with liquefaction probability curves these curves were based on complementary cumulative frequency distributions of the liquefaction potential index lpi for surficial geologic units in the study area lpi values were computed with extensive cone penetration test soundings maps were developed for three earthquake scenarios an m 7 8 event on the san andreas fault comparable to the 1906 event an m 6 7 event on the hayward fault comparable to the 1868 event and an m 6 9 event on the calaveras fault ground motions were esti mated with the boore and atkinson 2008 attenuation relation liquefaction is pre dicted for all three events in young holocene levee deposits along the major creeks liquefaction probabilities are highest for the m 7 8 earthquake ranging from 0 33 to 0 37 if a 1 5 m deep water table is assumed and from 0 10 to 0 14 if a 5 m deep water table is assumed liquefaction probabilities of the other surficial geologic units are less than 0 05 probabilities for the scenario earthquakes are generally consistent with observations during historical earthquakes

shear wave velocity and seismic response of near surface sediments in charleston south carolina six major geologic units in charleston south carolina are characterized in terms of shear wave velocity v s in this article the characterization is based on in situ v s measurements at 91 sites the six units are man made fills holocene and late pleistocene deposits the wando formation the ten mile hill beds the penholoway formation and the daniel island beds and tertiary deposits median v s values for these units in the top 25 m are 145 111 189 176 285 and 399 m sec respectively for tertiary deposits in the depth intervals of 25 55 m 55 75 m and 75 100 m median v s values are 435 533 and 663 m sec respectively a seismic response parametric study is conducted assuming several soil rock models and two input rock outcrop motions with peak accelerations of 0 3 g and 0 1 g it is found that quaternary sections with v s of 190 m sec e g the wando formation and thicknesses of about 7 m to 15 m exhibit predominant peaks in the acceleration response spectra at periods of about 0 25 to 0 4 sec these predominant peaks match fundamental periods of many existing buildings in the old city district of charleston the results suggest that local site conditions contributed to building damage in the 1886 charleston earthquake

stability of highly fractured infinite rock slopes with nonlinear failure criteria and nonassociated flow laws the effect of the dilatancy phenomenon on rock masses is not usually considered when calculating slope stability a theoretical analysis has been conducted on the stability of infinite rock slopes

liquefaction potential assessment of pleistocene beach sands near charleston south carolina abstract liquefaction potential of four pleistocene beach sand deposits in the greater charleston area south carolina is assessed the assessment is based on a review of 51 sites of conspicuous craterlets and horizontal ground displacement that occurred in beach sand deposits during the 1886 charleston earthquake and an analysis of 82 seismic cone penetration tests with pore pressure measurements of the 51 ground failure sites 23 are associated with the ten mile hill beds 13 with the wando formation 13 with the silver bluff terrace and younger deposits that lie adjacent to the harbor rivers and creeks and two with the ladson formation liquefaction potential is analyzed using the seismic cone data with and without correction for age related processes diagenesis and then expressed in terms of the liquefaction potential index lpi probability curves are developed from the lpi calculations for different earthquake ground shaking parameters the probability curves for the wando formation overpred

the effect of land plants on weathering rates of silicate minerals abstract land plants and their associated microbiota directly affect silicate mineral weathering in several ways by generation of chelating ligands by modifying ph through production of co2 or organic acids and by altering the physical properties of a soil particularly the exposed surface areas of minerals and the residence time of water in laboratory experiments far from equilibrium 1 mm oxalate a strong chelator of al has a negligible effect on the dissolution rate of alkali feldspars but some effect on calcic feldspars and olivine by analogy to oxalate the overall effect of organic ligands on the weathering rate of silicate minerals in nature is likely to be small except perhaps in microenvironments adjacent to roots and fungal hyphae the effect of ph on silicate mineral dissolution rate depends on ph below ph 4 5 the rate increases with decreasing ph in the circumneutral region the rate is ph independent and at ph values above around 8 the rate increases with increasing ph vegetation should thus cause an increase in weathering rate through the ph effect only where the ph is below 4 5 as an overall generalization the effect of plants on weathering rate through changes in soil solution chemistry is probably small for granitic rocks it may be greater for more mafic rocks it is the release of ca and mg from mafic rocks that has the greatest influence on the global co2 budget the effect of changes in soil physical properties on weathering rate can be major by binding fine particles plants can greatly increase weathering rates in areas of high physical erosion where erosion rates are lower the effect of plants is less clear on long timescales plants may decrease chemical weathering by binding secondary products and isolating unweathered minerals from meteoric water a major unknown in estimating the effect of the advent of land plants on weathering rates is the nature thickness particle size distribution permeability of the regolith on the pre silurian continents the indirect effect of vegetation through changing the regional distribution of precipitation may be as important as the direct effects

soil column depth dependent seismic site coefficients and hazard maps for the upper mississippi embayment abstract the presence of deep unconsolidated deposits in the upper mississippi embayment ume has an important impact on surface motions and has been the subject of several studies including a study by two of us who integrated probabilistic seismic hazard analysis psha with nonlinear site effects nl this study extends the psha nl procedure to 1 incorporate a finite fault model capable of generating near source motions instead of using point source models only 2 better approximate the range of available attenuation relations for the central and eastern united states ceus 3 examine the hazard at very high levels of shaking and 4 propagate generated rock motions through randomized soil profile properties to achieve a more consistent probabilistic procedure the extended psha nl procedure is used to develop updated depth dependent site coefficients for the ume which generally provides a lower hazard at short periods but a higher hazard at longer periods than current approaches proposed probabilistic seismic hazard maps at selected spectral accelerations that incorporate the proposed site effects are also presented for the ume and are systematically compared with seismic hazard maps proposed by others

seasonal and event scale variations in solute chemistry for four sierra nevada catchments abstract hydrobiogeochemical processes controlling stream water chemistry were examined in four small 2 catchments having contrasting bedrock lithologies in the western sierra nevada foothills of california the mediterranean climate with its cool wet and hot dry cycle produces strong seasonal patterns in hydrological biological and geochemical processes stream water solutes fall into three general groups according to seasonal fluctuation in concentration strong rainy season minimum dry season maximum cl so 4 2 base cations weak rainy season minimum dry season maximum si and rainy season maximum dry season minimum no 3 and k solute dynamics in soil solutions and stream water suggest that mixing of drainage waters from bedrock and soil sources regulate stream water solute concentrations patterns are further altered by the leaching of solutes accumulated in the soil over the summer period of desiccation and the temporal discoupling of nutrient cycles that occurs due to differences in the timing between vegetation growth late spring and leaching early winter solute concentrations are remarkably similar between watersheds with varying bedrock types with the exception of nitrate sulfate and bicarbonate three watersheds have nitrogen bearing metasedimentary bedrock that contributes to elevated nitrate concentrations in stream waters watersheds whose bedrock includes mineralized veins of sulfide and carbonate minerals similarly have greater sulfate and bicarbonate concentrations in stream water hydrobiogeochemical processes are highly dynamic at the seasonal and storm event temporal scales and spatially complex at the watershed scale making management of stream water chemical composition such as nitrate concentrations very challenging

critical parameters affecting bias and variability in site response analyses using kik net downhole array data because of the limited number of strong motion records that have measured ground response at large strains any statistical analyses of seismic site response models subject to strong ground motions are severely limited by a small number of observations recent earthquakes in japan including the m w 9 0 tohoku earthquake of march 2011 have substantially increased the observations of strong motion records that can be used to compare alternative site response models at large strains and can subsequently provide insight into the accuracy and precision of site response models using the kiban kyoshin network kik net downhole array data in japan we analyze the accuracy bias and variability precision resulting from common site response modeling assumptions and we identify critical parameters that significantly contribute to the uncertainty in site response analyses we perform linear and equivalent linear site response analyses at 100 kik net sites using 3720 ground motions ranging in amplitude from weak to strong 204 of these records have peak ground accelerations greater than graphic 1 at the ground surface we find that the maximum shear strain in the soil profile the observed peak ground acceleration at the ground surface and the predominant spectral period of the surface ground motion are the best predictors of where the evaluated models become inaccurate and or imprecise the peak shear strains beyond which linear analyses become inaccurate in predicting surface pseudospectral accelerations psa presumably as a result of nonlinear soil behavior are a function of vibration period and are between 0 01 and 0 1 for periods 0 5 s do not display noticeable effects of nonlinear soil behavior online material site specific information and model residuals at 100 kik net stations 1 embed inline graphic 1 gif

seismic moment assessment of earthquakes in stable continental regions iii new madrid 1811 1812 charleston 1886 and lisbon 1755 summary the sizes of three major or great historical earthquakes are reassessed using the isoseismal area regression tools developed in parts i and ii of this study of stable continental region scr seismicity the earthquakes are 1811 new madrid central united states and its following sequence 1886 charleston coastal south carolina and 1755 lisbon oceanic intraplate off the continental shelf of portugal the analysis confirms the large size of these events and for the first time places constraints on the uncertainty of their seismic moment release because of the exceptionally low seismic wave attenuation of eastern north america ena a separate north american regression of seismic moment on isoseismal area was developed additionally the unknown western extents of the new madrid isoseismal areas were calibrated with the patterns of the m 6 3 6 6 1843 and 1895 earthquakes application of part ii analysis procedures with these corrections yields new madrid size estimates expressed as moment magnitude of m 8 1 0 31 for the 1811 december 16 m 7 8 0 33 for the 1812 january 23 and m 8 0 0 33 for the 1812 february 7 principal events the charleston earthquake s magnitude decreases from m 7 4 to m 7 3 0 26 after compensation for the effect of coastal plain sediments on its inner isoseismals intensity regressions for lisbon are calibrated against the isoseismal pattern of the nearly co located m 7 8 1969 st vincent earthquake which in this case increases the predicted size of lisbon from m 8 4 to m 8 7 0 39 these size estimates are supported by data from independent phenomena extent and severity of liquefaction the maximum distance of induced landslides and for lisbon tsunami wave amplitudes estimated source parameters are controlled by crustal or lithospheric temperature which governs the depth extent of brittle faulting using estimated continental and oceanic geotherms viable fault lengths are 30 80 km for charleston 120 180 km for 1811 new madrid and 180 280 km for lisbon for average displacements of 2 4 m 8 11 m and 10 14 m respectively and for average static stress and strain drops at the estimated seismic moments of this study the 1811 new madrid and the 1755 lisbon events are respectively the largest known scr and oceanic lithosphere earthquakes

hydrochemical patterns of a small lake and a stream in an uplifting area proposed as a repository site for spent nuclear fuel forsmark sweden hydrochemical patterns of a small lake and a stream in an uplifting area proposed as a repository site for spent nuclear fuel forsmark sweden

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

nitrogen and carbon flow from rock to water regulation through soil biogeochemical processes mokelumne river watershed california and grand valley colorado 1 soil denitrification is an ecologically important nitrogen removal mechanism that releases to the atmosphere the greenhouse gas n2o an intermediate product from the reduction of no3 to n2 in this study we evaluate the relationship between soil carbon and denitrification potential in watersheds with bedrock acting as a nonpoint source of nitrogen testing the hypothesis that nitrate leaching to stream water is in part regulated by denitrification two sites one in a mediterranean climate and the other in an arid climate were investigated to understand the interplay between carbon and denitrification potential both sites included carbonaceous bedrock with relatively high nitrogen concentrations 1 000 mg n kg 1 and had low background nitrogen concentrations in surface and groundwater there was a net accumulation of carbon and nitrogen in soil relative to the corresponding bedrock with the exception of carbonaceous shale from the arid site there the concentration of carbon in the soil 15 620 mg c kg 1 was less than the shale parent 22 460 mg c kg 1 consistent with the bedrock being a source of soil carbon rates of denitrification potential 0 5 83 g n kg 1 hr 1 derived from laboratory incubations appeared to be related to the ratio of dissolved organic carbon and nitrate extracted from soils these data indicate that microbial processes such as denitrification can help maintain background nitrogen concentrations to tens of m n in relatively undisturbed ecosystems when nitrogen inputs from weathering bedrock are accompanied by sufficient organic carbon concentrations to promote microbial nitrogen transformations

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

assessment of the liquefaction susceptibility of fine grained soils observations from recent earthquakes and the results of cyclic tests indicate that the chinese criteria are not reliable for determining the liquefaction susceptibility of fine grained soils fine grained soils that liquefied during the 1994 northridge 1999 kocaeli and 1999 chi chi earthquakes often did not meet the clay size criterion of the chinese criteria cyclic testing of a wide range of soils found to liquefy in adapazari during the kocaeli earthquake confirmed that these fine grained soils were susceptible to liquefaction it is not the amount of clay size particles in the soil rather it is the amount and type of clay minerals in the soil that best indicate liquefaction susceptibility thus plasticity index pi is a better indicator of liquefaction susceptibility loose soils with pi 0 85 were susceptible to liquefaction and loose soils with 12 0 8 were systematically more resistant to liquefaction soils with pi 18 tested at low effective confining stresses

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

impediments to predicting site response seismic property estimation and modeling simplifications abstract we compare estimates of the empirical transfer function etf to the plane sh wave theoretical transfer function ttf within a laterally constant medium for invasive and noninvasive estimates of the seismic shear wave slownesses at 13 kiban kyoshin network stations throughout japan the difference between the etf and either of the ttfs is substantially larger than the difference between the two ttfs computed from different estimates of the seismic properties we show that the plane sh wave ttf through a laterally homogeneous medium at vertical incidence inadequately models observed amplifications at most sites for both slowness estimates obtained via downhole measurements and the spectral analysis of surface waves strategies to improve the predictions can be separated into two broad categories improving the measurement of soil properties and improving the theory that maps the 1d soil profile onto spectral amplification using an example site where the 1d plane sh wave formulation poorly predicts the etf we find a more satisfactory fit to the etf by modeling the full wavefield and incorporating spatially correlated variability of the seismic properties we conclude that our ability to model the observed site response transfer function is limited largely by the assumptions of the theoretical formulation rather than the uncertainty of the soil property estimates

amplification factors for spectral acceleration in tectonically active regions empirical relationships are developed to predict amplification factors for 5 damped response spectral acceleration period range t 0 01 5 sec as a function of site category we evaluate amplification factors by normalizing response spectral accelerations computed from recordings by reference spectral accelerations derived from a modified attenuation relationship for active regions strong motion sites are categorized according to several schemes which are based on surface geology age only age depositional environment and age material texture shallow 30 m shear wave velocity and geotechnical data criteria for selection of the optimal classification scheme are that the amplification models for categories within the scheme 1 minimize the global dispersion of prediction residuals and 2 are significantly distinct across a broad period range the results of the regressions indicate that the greatest levels of distinction in amplification levels across categories occur for the shallow shear wave velocity scheme but that the dispersion of residuals for this scheme are relatively high for soil sites although not for rock sites conversely schemes based on detailed surface geology generally have the smallest dispersion for soil sites but amplification levels across quaternary categories are only significantly distinct at small periods these findings suggest that detailed surface geology provides an effective means of soil site categorization at small periods whereas shallow shear wave velocity provides an effective means for rock site categorization at small periods at longer periods none of the schemes are optimized relative to both the dispersion and distinction criteria the principal application of the amplification factors is as a modifier of attenuation relations much like a site term the present results significantly reduce the bias associated with the site terms in a widely used attenuation relationship for rock and soft soil site conditions manuscript received 25 february 2002

site response models for charleston south carolina and vicinity developed from shallow geotechnical investigations the study models the response of near surface materials in charleston south carolina and the adjacent area geotechnical investigations at 281 locations were made available by local engineering firms the data used for dynamic site response analysis were derived from shear wave velocity measurements at 52 loca tions site response was quantified as the ratio of surface motion to hypothetical hard rock basement outcrop motion scenario earthquake motions were developed with the stochastic model acceleration response ratios for 5 critical oscillator damping were computed for 12 frequencies ranging from 0 1 to 30 hz and for peak ground acceleration two features determine the general nature of site response in the study area the impedance contrast between mesozoic basement and cretaceous sediments and the shallow impedance contrast between quaternary and tertiary sediments average s wave velocities in the quaternary are relatively uniform and range from 150 to 250 m sec they are not strongly correlated with surface geology the velocities of the immediately underlying tertiary sediments range from 300 to 500 m sec because of the uniformity of velocity in the quaternary depth to the quaternary tertiary contact appears to be the most important variable leading to differences in calculated site response this surface is irregular and varies in depth from near surface at inland sites to approximately 30 m at sites near the coast as a consequence estimated site response in the frequency band 1 10 hz varies by as much as a factor of 3 site response at frequencies less than 1 hz is dominated by the first few resonant har monics of the entire sedimentary section with fundamental frequency near 0 2 hz

geochemical response to variable streamflow conditions in contaminated and uncontaminated streams 1 seasonal variations in stream inorganic geochemistry are not well documented or understood we sampled two mining impacted and two relatively pristine streams in western montana over a 12 month period collecting samples every 4 weeks with supplemental sampling at least weekly during spring runoff we analyzed all samples for dissolved operationally defined as 0 2 m and total recoverable concentrations generally the trace elements al as cu fe mn and zn did not correlate linearly with streamflow while the major elements e g ca k and mg did suspended sediment total recoverable metals and h followed clockwise hysteresis rotations driven by short term flushing events during the very early stages of spring runoff mining impacted sites had higher concentrations of many trace elements than did relatively pristine sites one of the mining impacted sites exhibited strong geochemical responses to spring rain events in the basin the results underscore the need to sample streams frequently during changing hydrologic and climatic conditions in order to accurately monitor surface water quality and to determine solute and particulate loads both contaminant and noncontaminant

liquefaction potential index field assessment cone penetration test cpt soundings at historic liquefaction sites in california were used to evaluate the predictive capability of the liquefaction potential index lpi which was defined by iwasaki et al in 1978 lpi combines depth thickness and factor of safety of liquefiable material inferred from a cpt sounding into a single parameter lpi data from the monterey bay region indicate that the probability of surface manifestations of liquefaction is 58 and 93 respectively when lpi equals or exceeds 5 and 15 lpi values also generally correlate with surface effects of liquefaction decreasing from a median of 12 for soundings in lateral spreads to 0 for soundings where no surface effects were reported the index is particularly promising for probabilistic liquefaction hazard mapping where it may be a useful parameter for characterizing the liquefaction potential of geologic units

controls on surface water chemistry in two lake watersheds in the adirondack region of new york differences in nitrogen solute sources and sinks the southwestern adirondack region of new york receives among the highest rates of atmospheric nitrogen n deposition in the usa atmospheric n deposition to sensitive ecosystems like the adirondacks may increase the acidification of soils through losses of exchangeable nutrient cations and the acidification of surface waters associated with enhanced mobility of nitrate no3 however watershed attributes including surficial terrestrial characteristics in lake processing and geological settings have been found to complicate the relationships between atmospheric n deposition and n drainage losses we studied two lake watersheds in the southwestern adirondacks grass pond and constable pond which are located in close proximity 26 km and receive similarly high n deposition but have contrasting watershed attributes e g wetland area geological settings since the difference in the influence of n deposition was minimal we were able to examine both within and between watershed influences of land cover the contribution of glacial till groundwater inputs and in lake processes on surface water chemistry with particular emphasis on n solutes and dissolved organic carbon doc monthly samples at seven inlets and one outlet of each lake were collected from may to october in 1999 and 2000 the concentrations of no3 were high at the grass pond inlets especially at two inlets and no3 was the major n solute at the grass pond inlets the concentrations of likely weathering products i e dissolved si ca2 mg2 na as well as acid neutralizing capacity and ph values were also particularly high at those two grass pond inlets suggesting a large contribution of groundwater inputs dissolved organic n don was the major n solute at the constable pond inlets the higher concentrations of don and doc at the constable pond inlets were attributed to a large wetland area in the watershed the doc don ratios were also higher at the constable pond inlets possibly due to a larger proportion of coniferous forest area although don and doc were strongly related the stronger relationship of the proportion of wetland area with doc suggests that additional factors regulate don the aggregated representation of watershed physical features i e elevation watershed area mean topographic index hypsometric analysis index was not clearly related to the lake n and doc chemistry despite distinctive differences in inlet n chemistry no3 and don concentrations at the outlets of the two lakes were similar the lower doc don ratios at the lake outlets and at the inlets having upstream ponds suggest the importance of n processing and organic n sources within the lakes although an inverse relationship between no3 and doc don has been suggested to be indicative of a n deposition gradient the existence of this relationship for sites that receive similar atmospheric n deposition suggest that the relationship between no3 and the doc don ratio is derived from environmental and physical factors our results suggest that despite similar wet n deposition at the two watershed sites n solutes entering lakes were strongly affected by hydrology associated with groundwater contribution and the presence of wetlands whereas n solutes leaving lakes were strongly influenced by in lake processing copyright 2006 john wiley sons ltd

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

ultimate bearing capacity at the tip of a pile in rock based on the modified hoek brown criterion a method for calculating the ultimate bearing capacity at the tip of a pile is presented

mapping liquefaction potential of aged soil deposits in mount pleasant south carolina liquefaction potential of aged soil deposits in mount pleasant south carolina based on the 1886 charleston earthquake is characterized in this paper the characterization involves reviewing available first hand accounts of 1886 ground behavior analyzing cone penetration test cpt and shear wave velocity data and correlating the results with geology careful review of the first hand accounts reveals that nearly all cases of surface effects of liquefaction can be associated with the younger sand deposits that lie adjacent to the harbor rivers and creeks only one documented case of minimal surface effect of liquefaction can be definitely associated with the older sand deposits of the 100 000 year old wando formation ratios of measured to estimated shear wave velocity indicate that the younger sand deposits and the older sand deposits have measured velocities that are 9 and 38 respectively greater than 6 year old sand deposits with the same cpt tip resistance liquefaction potential is expressed in terms of the liquefaction potential index lpi proposed by iwasaki and others lpi values for the wando sands computed from the cpt profiles are incorrectly high if no age corrections are applied if age corrections are applied computed lpi values match well the observed field behavior in both the younger sands and the older sands the results are combined with a 1 24 000 scale geologic map to produce a liquefaction potential map of mount pleasant the findings of this study agree remarkably well with a previous liquefaction potential study of aged soil deposits on charleston peninsula

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

stability analysis of rock slopes subjected to seepage forces using the modified hoek brown criterion abstract the paper deals with the stability analysis of a water saturated rock slope by means of the kinematic approach of limit analysis theory particular emphasis is first given to the effects of pore water pressure on the global stability of geotechnical structures the rock strength properties being formulated in terms of effective stresses it is shown how the effect of seepage flow may be accounted for such an analysis through driving body forces derived from the gradient of excess pore pressure distribution is shown the latter is obtained as the solution to a hydraulic boundary value problem and then incorporated as external loading in the subsequent stability analysis the rock strength properties are modeled by a modified hoek brown failure criterion for which closed form expressions of the support functions have been derived in a previous paper the approach is then applied to investigate the stability of rock slopes computational results are given providing ample evidence of the destablizing effects induced by the seepage forces the influence of relevant geometrical strength and loading parameters is also discussed

structural and tectonic setting of the charleston south carolina region evidence from the tertiary stratigraphic record eleven upper eocene through pliocene stratigraphic units occur in the subsurface of the region surrounding charleston south carolina these units contain a wealth of information concerning the long term tectonic and structural setting of that area these stratigraphic units have a mosaic pattern of distribution rather than a simple layered pattern because deposition erosion and tectonic warping have interacted in a complex manner through time by generating separate structure contour maps for the base of each stratigraphic unit an estimate of the original basal surface of each unit can be reconstructed over wide areas changes in sea level over geologic time generate patterns of deposition and erosion that are geographically unique for the time of each transgression such patterns fail to persist when compared sequentially over time in some areas however there has been persistent repetitive net downward or upward movement over the past 34 m y these repetitive patterns of persistent motion are most readily attributable to tectonism the spatial pattern of these high and low areas is complex but it appears to correlate well with known tectonic features of the region this correlation suggests that the tectonic setting of the charleston region is controlled by scissors like compression on a crustal block located between the north trending adams run fault and the northwest trending charleston fault tectonism is localized in the charleston region because it lies within a discrete hinge zone that accommodates structural movement between the cape fear arch and the southeast georgia embayment

liquefaction susceptibility criteria for silts and clays new liquefaction susceptibility criteria for saturated silts and clays are presented that are based on the mechanics of their stress strain behavior and which provide improved guidance for selecting engineering procedures for estimating potential strains and strength loss during seismic loading monotonic and cyclic undrained loading test data for silts and clays show that they transition over a fairly narrow range of plasticity indices pi from soils that behave more fundamentally like sands sand like behavior to soils that behave more fundamentally like clays clay like behavior with the distinction having a direct correspondence to the type of engineering procedures that are best suited to evaluating their seismic behavior it is recommended that the term liquefaction be reserved for describing the development of significant strains or strength loss in fine grained soils exhibiting sand like behavior whereas the term cyclic softening failure be used to describe similar phenomena in fine grained soils exhibiting clay like behavior for practical purposes clay like behavior can be expected for fine grained soils that have pi 7 although a slightly lower transition point for soils with a cl ml classification perhaps pi 5 or 6 would be equally consistent with the available data issues related to the practical application of these criteria are discussed

ultimate bearing capacity of rock masses based on modified mohr coulomb strength criterion a method for calculating the bearing capacity of spread foundations in rock is presented bearing capacity of spread foundations on rock masses based on modified mohr coulomb strength criterion charts and figures are presented for a quick obtaining of bearing capacity for shallow foundations comparison of the ultimate bearing capacity using the hoek and brown criterion and the modified mohr coulomb strength criterion