earthquake ground motion estimation using strong motion records a review of equations for the estimation of peak ground acceleration and response spectral ordinates abstract engineering seismology is the link between earth sciences and engineering the main input of engineering seismology in engineering design are loading conditions which must satisfy certain conditions regarding their level and frequency of occurrence during the lifetime of a structure one method for estimating these loading conditions is through equations based on strong ground motion recorded during previous earthquakes these equations have a handful of independent parameters such as magnitude and source to site distance and a dependent parameter such as peak ground acceleration pga or spectral acceleration and the coefficients in the equation are usually found by regression analysis this review examines such equations in terms of data selection accelerogram processing techniques of the strong motion records used to construct the equations the characterisation of earthquake source travel path and local site used and regression techniques employed to find the final equations it is found that little agreement has been reached in the past 30 years of ground motion estimation relation studies workers have chosen their techniques based on the available data which varies greatly with geographical region also it is noted that there is a need to include more independent parameters into ground motion estimation equations if the large uncertainties associated with such equations are to be significantly reduced the data required to do this is unfortunately scarce

magnitude dependent variance of peak ground acceleration abstract we examine the variability of peak horizontal and vertical accelerations of the large california strong motion data set for the time period 1957 to 1991 and find a statistically significant dependence of the standard error on earthquake magnitude specifically the standard error decreases with increasing magnitude the analysis was conducted using a rigorous methodology that examines both earthquake to earthquake inter event variability and within earthquake intra event variability the magnitude dependence is stronger for inter event variability than intra event variability and stronger for horizontal peak acceleration than for vertical peak acceleration the data from the recent landers big bear and northridge earthquakes are consistent with these results

control of hazard due to seismicity induced by a hot fractured rock geothermal project in 2003 hydraulic stimulations were carried out in a geothermal field in eastern el salvador central america as part of a project to explore the feasibility of commercial hot fractured rock energy generation a key requisite for this environmentally friendly energy source is that the fracturing of the hot rocks at depths of 1 2 km must not produce levels of ground shaking at the surface that would present a serious disturbance or threat to the local population thresholds of tolerable ground motion were inferred from guidelines and regulations on tolerable levels of vibration and from correlations between instrumental strong motion parameters and intensity considering the vulnerability of the exposed housing stock the thresholds were defined in terms of peak ground velocity pgv and incorporated into a traffic light system that also took account of the frequency of occurrence of the induced earthquakes the system was implemented through a dedicated seismograph array and locally derived predictive equations for pgv the traffic light was used as a decision making tool regarding the duration and intensity of pumping levels during the hydraulic stimulations the system was supplemented by a small number of accelerographs and re calibrated using records obtained during the rock fracturing

empirical ground motion attenuation relations for the eastern alps in the magnitude range 2 5 6 3 in this paper we use a large data set of seismometric and accelerometric recordings 3168 vertical and 1402 for each of the horizontal components collected by various networks in the eastern alps to estimate empirical ground motion attenuation relations valid in the magnitude range 2 5 6 3 for distances of up to 130 km relations are developed for horizontal and vertical peak ground acceleration and velocity arias intensity response spectral acceleration and fourier amplitude for 46 periods between 0 1 and 2 sec we adopt a simple magnitude dependent attenuation model predicting closer attenuation curves and decreasing distance attenuation for increasing magnitude we use truncated regression analysis to deal with the problem of non triggering stations with respect to other approaches our solution does not require any discarding of data or the knowledge of which stations did not trigger our relations agree with others suitable for the study region for magnitudes greater than 5 8 while they have a faster attenuation for lower magnitudes in an attempt to reduce the standard deviation we have introduced soil classification into the relation as well as a characterization of sites by means of h v ratios these ratios were estimated either by earthquakes receiver function or by the background seismic noise nakamura s ratios similar to findings in other studies the improvement obtained with soil classification is negligible while h v ratios reduce the standard deviation by up to 22 finally we have investigated the implications of these new relations for seismic hazard assessment considering two sites of interest located in northeastern italy udine and gemona in both cases the difference in the hazard estimates for return periods shorter than 100 years is notable with respect to all other available relations

ground motion prediction equations for south korea peninsula abstract ground motion prediction equations gmpes play a crucial role for estimating the seismic hazard in any region using either a deterministic or a probabilistic approach indeed they represent a reliable and fast tool to predict strong ground motion given source and propagation parameters in this article we estimated gmpes for the south korea peninsula gmpes were computed for peak ground displacement peak ground velocity peak ground acceleration and spectral accelerations damping at 5 at 13 different periods from 0 055 to 5 s we analyzed data from 222 earthquakes recorded at 132 three component stations of the south korea seismic network from 2007 to 2012 with local magnitude ranging between 2 0 and 4 9 and epicentral distances varying from 1 4 to 600 km a nonlinear mixed effects technique is used to infer the gmpe coefficients this technique includes both fixed and random effects and accounts for both inter and intraevent dependencies in the data station specific corrective coefficients were estimated by a statistical approach and were included in the final ground motion prediction model finally predictions for peak ground acceleration and spectral acceleration are compared with observations recorded for an m l 5 1 earthquake that occurred in 2014 the data for which were not included in the modeling online material figures showing final ground motion prediction equation models versus observations and intra and interevent residuals

characterization of earthquake induced ground motion from the l aquila seismic sequence of 2009 italy summary based only on weak motion data we carried out a combined study on region specific source scaling and crustal attenuation in the central apennines italy our goal was to obtain a reappraisal of the existing predictive relationships for the ground motion and to test them against the strong motion data peak ground acceleration pga peak ground velocity pgv and spectral acceleration sa gathered during the mw 6 15 l aquila earthquake 2009 april 6 01 32 utc the l aquila main shock was not part of the predictive study and the validation test was an extrapolation to one magnitude unit above the largest earthquake of the calibration data set the regional attenuation was determined through a set of regressions on a data set of 12 777 high quality high gain waveforms with excellent s n ratios 4259 vertical and 8518 horizontal time histories seismograms were selected from the recordings of 170 foreshocks and aftershocks of the sequence the complete set of all earthquakes with ml 3 0 from 2008 october 1 to 2010 may 10 all waveforms were downloaded from the iside web page http iside rm ingv it iside standard index jsp a web site maintained by the istituto nazionale di geofisica e vulcanologia ingv weak motion data were used to obtain a moment tensor solution as well as a coda based moment rate source spectrum for each one of the 170 events of the l aquila sequence 2 8 mw 6 15 source spectra were used to verify the good agreement with the source scaling of the colfiorito seismic sequence of 1997 1998 recently described by malagnini et al 2008 finally results on source excitation and crustal attenuation were used to produce the absolute site terms for the 23 stations located within 80 km of the epicentral area the complete set of spectral corrections crustal attenuation and absolute site effects was used to implement a fast and accurate tool for the automatic computation of moment magnitudes in the central apennines

a probabilistic approach to seismic hazard in metropolitan france in this study we applied a probabilistic methodology to seismic hazard assessment in metropolitan france for that purpose we determined an attenuation law adapted to the french context this law holds for peak ground acceleration on stiff bedrock for earthquakes with local magnitudes between 2 5 and 5 6 recorded in near field at distances between 3 and 50 km geological conditions are taken into account by means of a three categories classification of lithologies based on a 1 1 000 000 geological map the seismotectonic zonation consists of areas of diffuse seismicity characterized by a frequency magnitude distribution in southeastern france active faults are considered in a test case and are assumed to follow the characteristic earthquake model we performed hazard curves for six french cities and maps of peak horizontal ground accelerations expected for return periods of 475 975 and 1975 years in the country sensitivity tests have been performed the uncertainty introduced by ground motion variability seems minor compared with that due to the choice of the attenuation law this study points to the importance of testing internal consistency of the various data and laws used in any seismic hazard analysis in particular here the type of magnitude used to predict ground motion if not some systematic bias is introduced that may result in systematic errors on peak ground acceleration determination we also show that the introduction of possibly very large and infrequent events known only from paleoseismic investigations may have a dramatic impact on the hazard especially when long periods of time are considered

a monte carlo method for probabilistic hazard assessment of induced seismicity due to conventional natural gas production abstract a monte carlo approach to probabilistic seismic hazard analysis is developed for a case of induced seismicity associated with a compacting gas reservoir the geomechanical foundation for the method is the work of kostrov 1974 and mcgarr 1976 linking total strain to summed seismic moment in an earthquake catalog our monte carlo method simulates future seismic hazard consistent with historical seismic and compaction datasets by sampling probability distributions for total seismic moment event locations and magnitudes and resulting ground motions ground motions are aggregated over an ensemble of simulated catalogs to give a probabilistic representation of the ground motion hazard this approach is particularly well suited to the specific nature of the time dependent induced seismicity considered we demonstrate the method by applying it to seismicity induced by reservoir compaction following gas production from the groningen gas field a new ground motion prediction equation gmpe tailored to the groningen field has been derived by calibrating an existing gmpe with local strong motion data for 2013 2023 we find a 2 chance of exceeding a peak ground acceleration of 0 57 g and a 2 chance of exceeding a peak ground velocity of 22 cm s above the area of maximum compaction disaggregation shows that earthquakes of m w 4 5 at the shortest hypocentral distances of 3 km and ground motions two standard deviations above the median make the largest contributions to this hazard uncertainty in the hazard is primarily due to uncertainty about the future fraction of induced strains that will be seismogenic and how ground motion and its variability will scale to larger magnitudes

the influence of magnitude range on empirical ground motion prediction a key issue in the assessment of seismic hazard in regions of low to moderate seismicity is the extent to which accelerograms obtained from small magnitude earthquakes can be used as the basis for predicting ground motions due to the larger magnitude events considered in seismic hazard analysis in essence the question is whether empirical ground motion prediction equations can be applied outside their strict range of applicability as defined by the magnitude and distance ranges covered by the datasets from which they are derived this question is explored by deriving new spectral prediction equations using an extended strong motion da taset from europe and the middle east covering the magnitude range mw 3 0 7 6 and comparing the predictions with previous equations derived using data from only mw 5 0 and above events the comparisons show that despite their complex func tional form including quadratic magnitude dependence and magnitude dependent attenuation the equations derived from larger magnitude events should not be extra polated to predict ground motions from earthquakes of small magnitude moreover the results suggest not only that ground motion prediction equations cannot be used outside the ranges of their underlying datasets but also that their applicability at the limits of these ranges may be questionable although only tested for smaller magni tudes the results could be interpreted to suggest that predictive equations also cannot be reliably extrapolated to higher magnitudes than those represented in the dataset from which they are derived a finding that has important implications for seismic hazard analysis the conclusion of the study is that empirical derivation of ground motion pre diction equations should be based on datasets extending at least one unit below the lower limit of magnitude considered in seismic hazard calculations the inclusion of small magnitude recordings results in a significant increase in the aleatory varia bility of the equations although it is yet to be established whether this is due to greater uncertainty in the associated metadata or whether ground motion variability is gen uinely dependent on earthquake magnitude

an alternative approach to probabilistic seismic hazard analysis in the aegean region using monte carlo simulation abstract the aegean is the most seismically active and tectonically complex region in europe damaging earthquakes have occurred here throughout recorded history often resulting in considerable loss of life the monte carlo method of probabilistic seismic hazard analysis psha is used to determine the level of ground motion likely to be exceeded in a given time period multiple random simulations of seismicity are generated to calculate directly the ground motion for a given site within the seismic hazard analysis we explore the impact of different seismic source models incorporating both uniform zones and distributed seismicity a new simplified seismic source model derived from seismotectonic interpretation is presented for the aegean region this is combined into the epistemic uncertainty analysis alongside existing source models for the region and models derived by a k means cluster analysis approach seismic source models derived using the k means approach offer a degree of objectivity and reproducibility into the otherwise subjective approach of delineating seismic sources using expert judgment similar review and analysis is undertaken for the selection of peak ground acceleration pga attenuation models incorporating into the epistemic analysis greek specific models european models and a next generation attenuation model hazard maps for pga on a rock site with a 10 probability of being exceeded in 50 years are produced and different source and attenuation models are compared these indicate that greek specific attenuation models with their smaller aleatory variability terms produce lower pga hazard whilst recent european models and next generation attenuation nga model produce similar results the monte carlo method is extended further to assimilate epistemic uncertainty into the hazard calculation thus integrating across several appropriate source and pga attenuation models site condition and fault type are also integrated into the hazard mapping calculations these hazard maps are in general agreement with previous maps for the aegean recognising the highest hazard in the ionian islands gulf of corinth and hellenic arc peak ground accelerations for some sites in these regions reach as high as 500 600 cm s 2 using european nga attenuation models and 400 500 cm s 2 using greek attenuation models

new moment magnitude scale evidence of stress drop magnitude scaling and stochastic ground motion model for the french west indies in this study we analyse records from the les saintes seismic sequence following the mw 6 3 earthquake of 2004 november 11 which occurred close to guadeloupe french west indies 485 earthquakes with magnitudes from 2 to 6 recorded at distances between 5 and 150 km are used s waves fourier spectra are analysed to simultaneously determine source path and site terms the results show that the duration magnitude routinely estimated for the events that occurred in the region underestimate moment magnitude by 0 5 magnitude units over the whole magnitude range from the inverted seismic moments and corner frequencies we compute brune s stress drops we show that stress drops increase with increasing magnitude the same pattern is observed on apparent stresses i e the seismic energy to moment ratio however the rate of increase diminishes at high magnitudes which is consistent with a constant stress drop model for large events using the results of the inversions we perform ground motion simulations for the entire data set using the smsim stochastic simulation tool the results show that a good fit 0 25 with observed data is achieved when the source is properly described by its moment magnitude and stress drop and when site effects are taken into account although the magnitude dependent stress drop model is giving better results than the constant stress drop model the interevent variability remains high which could suggest that stress drop depends on other parameters such as the depth of the hypocentre in any case the overall variability is of the same order of magnitude as usually observed in empirical ground motion prediction equations

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

a comparative study on attenuation and source scaling relations in the kanto tokai and chubu regions of japan using data from hi net and kik net abstract attenuation relations are derived for central japan broadly spanning the kant tokai and chubu regions using recordings of small earthquakes 2 0 m jma 4 0 japan meterological agency magnitude and moderate to large magnitude earthquakes 3 0 m jma 7 2 we independently analyze data from both small magnitude and moderate to large magnitude earthquakes to provide an insight into the use of attenuation relations derived in regions of low seismic activity a strong correlation is found between the attenuation parameters derived from each dataset we find that q is strongly depth dependent and that apparent geometrical decay increases with increasing hypocentral distance this is modeled by using a three segment decay function with the initial decay forced to 1 r moment magnitudes are close to the published m jma magnitude but are on average slightly higher an increase in stress drop with magnitude is required in order to model both the small magnitude and moderate to large magnitude datasets alternatively we show that a constant stress drop model is suitable to model the response spectra of both small magnitude and moderate to large magnitude earthquakes when considering the saturation of the source corner frequency due to a static site filter such as f max or we test our ability to predict strong ground motion by using our attenuation and source scaling relations derived from the small magnitude recordings to stochastically simulate peak ground acceleration peak ground velocity and 5 damped response spectral ordinates over a range of magnitudes and distances the residuals of this simulation are found to be largely independent of distance and magnitude we compare our attenuation relations against other relations derived for japan the residuals of these relations are analyzed and compared against those obtained from the model found in this study we find that in this study the prediction of strong ground motions is possible using small magnitude data and that the validity of the prediction extends across all magnitudes available for comparison 2 0 m jma 7 8 on the other hand by using an alternative published predictive relation for japan derived using large magnitude events peak ground acceleration is significantly overestimated for small magnitude earthquakes

na sws 1 1 a uniform database of teleseismic shear wave splitting measurements for north america 1 this version of shear wave splitting sws database db for north america na contains 6224 pairs of splitting parameters fast polarization directions and splitting times measured using all the available data recorded by digital broadband seismic stations over the period of 1980 2007 and archived at the incorporated research institutions for seismology data management center the measurements were produced using a set of robust procedures that involve automated batch processing and manual screening and were ranked quantitatively on the basis of a uniform criterion the result is a homogeneous database of individual rather than station averaged splitting parameters that can be used by a variety of geoscientists for the understanding of the structure and dynamics of the earth s deep interior beneath na this data brief describes the seismic data and techniques used to generate the sws results the spatial and azimuthal coverage and the limitations of the db the db will be periodically updated and enhanced by adding newly recorded data and by measuring splitting parameters using the pks and skks phases in addition to sks the database can be accessed at http www mst edu liukh sws

fluidization in dry landslides this paper aims at determining the physical properties affecting the distance travelled by landslides with dry particles and elucidating the mechanism of the properties affecting landslide fluidization the procedure is as follows laboratory landslide experiments were conducted to verify the simulation model which was proposed to represent the movement of landslides further sensitivity analysis for some physical properties affecting the travel distance were conducted using this model the simulation model could identify the coordinates velocity and angular velocity for every particle in three dimensional space and the kinetic energy of particles consumed by inelastic and frictional collision with each other in the model the travel distances of landslides simulated by the model were verified by laboratory experiments statistically where the physical properties for the particles and slope angle were changed then sensitivity analysis for the physical properties were conducted using the model to clarify the effect of the properties on the travel distance it was proven that there were no significant differences between the travel distances represented by the simulation model and those found experimentally using statistical analysis i e the simulation model could represent virtual real landslides from the sensitivity analysis using the simulation model the travel distances were positively correlated to volume or number of particles and negative correlated to the slope angle kinetic friction and rolling friction of particles when the initial potential energies were the same the mass of particles of equal size did not affect the distance travelled as the number of particles increased the simulated travel distances tended to be longer compared with theoretical travel distances calculated using the friction between particles and the slope consequently we could determine the distance of the lumped mass model as being critical between fluidized and non fluidized landslides

nonlinear soil response a reality geotechnical models consistently indicate that the stress strain relationship of soils is nonlinear and hysteretic especially at shear strains larger than 10 5 to 10 4 nonlinear effects such as an increase in damping and reduction in shear wave velocity as excitation strength increases are commonly recognized in the dynamic loading of soils on the other hand these effects are usually ignored in seismological models of ground motion prediction because of the lack of compelling corroborative evidence from strong motion observations the situation is being changed by recently obtained data explicit evidence of strong motion deamplification accompanied by changes in resonant frequencies are found in the data from the 1985 michoacan mexico and the 1989 loma prieta california earthquakes the events recorded by the vertical and surface accelerograph arrays in taiwan as well as a number of other events throughout the world evidence of nonlinear behavior becomes apparent beyond a threshold acceleration of 100 to 200 gal nonlinearity is considerable in cohesionless soil but may be negligible in stiff soils the findings of recent years indicate that nonlinear site effects are more common than previously recognized in strong motion seismology

empirical prediction equations for peak ground velocity derived from strong motion records from europe and the middle east peak ground velocity pgv has many applications in earthquake engineering but there are relatively few prediction equations for this parameter in comparison with the large numbers of equations for estimating peak ground accel eration and response spectral ordinates this lack of empirical equations for pgv has led to widespread use of the practice of scaling peak velocity from the 5 damped response spectral ordinate at 1 sec which is a poor substitute for direct prediction of the parameter responding to the need to provide equations for the prediction of pgv this article derives new equations using the strong motion database for the seismically active areas of europe and the middle east following a new processing of all of the records a total of 532 strong motion accelerograms recorded at distances of up to 100 km from 131 earthquakes with moment magnitudes ranging from m 5 to 7 6 are used to derive equations for both the larger and the geometric mean of the horizontal components the predictions are found to be broadly consistent with those from previous european equations and also with preliminary results from the next generation of attenuation nga project suggesting that systematic differences in ground motions from active crustal regions if any are sufficiently small not to prevent the combined use of strong motion data from southern europe western north america and other tectonically active areas of shallow crustal seismicity

a stochastic earthquake ground motion prediction model for the united kingdom low seismicity regions such as the united kingdom uk pose a challenge for seismic hazard analysis in view of the limited amount of locally recorded data available in particular ground motion prediction is faced with the problem that most of the instrumental observations available have been recorded at large distances from small earthquakes direct extrapolation of the results of regression on these data to the range of magnitudes and distances relevant for the seismic hazard analysis of engineered structures generally leads to unsatisfactory predictions the present study presents a new ground motion prediction equation gmpe for the uk in terms of peak ground acceleration pga peak ground velocity pgv and 5 damped pseudospectral acceleration psa based on the results of numerical simulations using a stochastic point source model calibrated with parameters derived from local weak motion data the predictions from this model are compared with those of previous gmpes based on uk data other gmpes derived for stable continental regions scrs as well as recent gmpes developed for the wider european area