a new attenuation relation for strong ground motion in japan based on recorded data following the 1995 hyogo ken nanbu kobe earthquake the japanese government in an effort to prevent future earthquake disasters installed networks consisting of a large number of strong motion observation stations further national seismic hazard maps were made available to the public on an internet website in march 2005 by the headquarters for earthquake research promotion however these maps indicate only the local seismic intensity for japan as empirically con verted from predicted peak velocity in consolidated soils for various applications other strong motion indexes such as the response spectral acceleration are required in this study a database of whole japanese strong ground motion records between 1963 and 2003 is established in order to identify a new standard attenuation relation for japan for response acceleration as well as peak value it is usually very difficult to determine a suitable model form due to the large variability of strong motion data and correlation among the model variables because the strong coupling of variables in an attenuation model and the statistical power of the data is often not large enough to determine the necessity of these parameters therefore in this study our model has only three variables earthquake magnitude shortest distance to the seismic fault plane and focal depth to improve predictions given by the model site correction terms are adopted and additional terms for correcting regional anomalous seismic intensity with respect to the base model are determined the good fit between the model and observed strong motion records suggests that the new model is reasonably robust

insufficient statistical model development of ground motion relations for regions with low seismicity abstract it is a special issue to model an earthquake ground motion relation gmr ground motion prediction equation for the seismic hazard analysis of regions with low seismicity a region specific gmr may be difficult to develop if there are only a few observations therefore different approaches criteria and procedures have been developed in seismology and earthquake engineering to apply appropriate gmrs from one region to another this is a special type of statistical model development we criticize this and corresponding research from the statistical point of view our evaluation criteria result from state of the art mathematical statistical analysis especially regression analysis

extracting time domain green s function estimates from ambient seismic noise 1 it has been demonstrated experimentally and theoretically that an estimate of the green s function between two seismic stations can be obtained from the time derivative of the long time average cross correlation of ambient noise between these two stations this tdgf estimate from just the noise field includes all tensor components of the green s function and these green s function estimates can be used to infer earth structure we have computed cross correlations using 1 to 30 continuous days of ambient noise recorded by over 150 broadband seismic stations located in southern california the data processing yielded thousands of cross correlation pairs for receiver separations from 4 500 km which clearly exhibit coherent broadband propagating dispersive wavetrains across frequency band 0 1 2 hz

the hudson bay free air gravity anomaly and glacial rebound current models of the laurentide deglaciation predict only 15 to 30 of the observed hudson bay free air gravity anomaly low unless these models are able to be modified the source of the remainder of this free air gravity anomaly must be sought elsewhere such as in mantle convection

sedimentary pyrite formation an update sedimentary pyrite formation during early diagenesis is a major process for controlling the oxygen level of the atmosphere and the sulfate concentration in seawater over geologic time the amount of pyrite that may form in a sediment is limited by the rates of supply of decomposable organic matter dissolved sulfate and reactive detrital iron minerals organic matter appears to be the major control on pyrite formation in normal non euxinic terrigenous marine sediments where dissolved sulfate and iron minerals are abundant by contrast pyrite formation in non marine freshwater sediments is severely limited by low concentrations of sulfate and this characteristic can be used to distinguish ancient organic rich fresh water shales from marine shales under marine euxinic conditions sufficient h2s is produced that the dominant control on pyrite formation is the availability of reactive iron minerals calculations based on a sulfur isotope model indicate that over phanerozoic time the worldwide average organic carbon to pyrite sulfur ratio of sedimentary rocks has varied considerably high cs ratios during permo carboniferous time can be explained by a shift of major organic deposition from the oceans to the land which resulted in the formation of vast coal swamps at that time low cs ratios compared to today during the early paleozoic can be explained in terms of a greater abundance of euxinic basins combined with deposition of a more reactive type of organic matter in the remaining oxygenated portions of the ocean the latter could have been due to lower oceanic oxygen levels and or a lack of transportation of refractory terrestrial organic matter to the marine environment due to the absence of vascular land plants at that time

zur systematik der kohlenstoff schwefel eisen verhaltnisse in auftriebssedimenten abundances of organic carbon sulfur and reactive iron in sediments of three upwelling environments peru oman and benguela suggest that organic carbon reduced sulfur ratios c s ratios in this category of marine sediments deviate considerably from previously established empirical ratios in normal marine sediments to clarify the discrepancies we investigated those components of the diagenetic system that limit the formation of pyrite sulfate concentrations and reduction rates in pore waters availability of reactive iron and the quantity and quality of organic matter all three limitations are evident in our sample pools the results suggest that c s ratios in recent and fossil marine sediments rich in organic matter may be unsuitable as paleoenvironmental indicators

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

topographic slope as a proxy for seismic site conditions and amplification we describe a technique to derive first order site condition maps directly from topographic data for calibration we use global 30 arc sec topographic data and v s 30 measurements here v s 30 refers to the average shear velocity down to 30 m aggregated from several studies in the u s as well as in taiwan italy and australia v s 30 values are correlated against topographic slope to develop two sets of parameters for deriving v s 30 one for active tectonic regions where topographic relief is high and one for stable shields where topography is more subdued by taking the gradient of the topography and choosing ranges of slope that maximize the correlation with shallow shear velocity observations we can recover to first order many of the spatially varying features of sitecondition maps developed for california our site condition map for the low relief mississippi embayment also predicts the bulk of the v s 30 observations in that region despite rather low slope ranges we find that maps derived from the slope of the topography is often well correlated with other independently derived regional scale site condition maps but the latter maps vary in quality and continuity and subsequently also in their ability to match observed v s 30 measurements contained therein alternatively the slope based method provides a simple approach to uniform site condition mapping

structure of the eastern cordillera of colombia implications for trap styles and regional tectonics the northwest margin of south america has undergone multiple phases of compressional deformation beginning in the late cretaceous and culminating in the pliocene pleistocene the latest phases miocene to pleistocene of this deformation created the eastern cordillera of colombia compressional structures in the eastern cordillera formed traps that have petroleum exploration potential these are generally in the form of fault bend and fault propagation folds containing top sealed reservoir and mature source rocks trap delineation although difficult to achieve because of the poor seismic quality obtained in the region can be accomplished by supplementing the seismic data with geometric analysis of surficial structures the eastern cordillera is asymmetrical with the dominant tectonic transport direction towards the east west directed thrust faults are localized along the western flank of the eastern cordillera and are interpreted to be back thrusts splaying off a deep mid crustal detachment a regional retrodeformable cross section across the eastern cordillera shows that basement detached deformation of late miocene to pliocene age was followed by pliocene to holocene uplift of the cordillera on high angle basement involved reverse faults these two structural styles were superimposed on preexisting jurassic and lower cretaceous grabens whose normal faults were partially inverted during the later stages of compressional deformation a palinspastic restoration of this regional cross section indicates that approximately 150 km of shortening 40 shortening has occurred 105 km eastward directed towards the llanos basin and 45 km westward directed towards the middle magdalena basin this calculated shortening is very close to that calculated by summing microplate motions for the northwest corner of south america shortening in the sedimentary cover rocks exceeds that in the basement rocks by about three times this shortening can be regionally balanced with a gently dipping mid crustal detachment that extends beneath the middle magdalena basin and central cordillera and which roots in the benioff zone beneath the western cordillera the presence of a mid crustal detachment as postulated here provides a mechanism to transmit the shortening from the convergent plate margin in the pacific to the andean foreland and is interpreted to have provided the structural link between the three ranges of the colombian andes the detachment also provides a mechanism to explain the imbalance of shortening seen between eastern cordillera basement and the overlying strata and implies that the western and central colombian andes have been tectonically transported eastwards a distance of at least 150 km

crustal structure beneath hudson bay from ambient noise tomography implications for basin formation summary the hudson bay basin is the least studied of four major phanerozoic intracratonic basins in north america and the mechanism by which it formed remains ambiguous we investigate the crustal structure of hudson bay based on ambient noise tomography using 21 months of continuous recordings from 37 broad band seismograph stations that encircle the bay green s functions that emerge from the cross correlation of these ambient noise recordings are dominated by fundamental mode rayleigh waves in the microseismic period band 5 20 s these signals are most prominently expressed in certain preferred azimuths indicative of stationary coastal source regions in southern alaska and labrador seasonal variations are subtle but consistent with more energetic noise sources during winter months when wave heights in the pacific and north atlantic are larger than in the summer noise emanating from hudson bay does not appear to contribute significantly to the cross correlograms group velocity dispersion curves are obtained by time frequency analysis of cross correlation functions we test and implement a signal to noise ratio snr selection method for producing one sided cross correlograms which yields better defined dispersion ridges than the standard two sided averaging approach tomographic maps and cross sections obtained in the 5 40 s period range reveal significantly lower crustal velocities beneath hudson bay than in the bounding archean superior craton the lowest mid crustal velocities correspond to a previously determined region of maximum lithospheric stretching near the centre of the basin pseudosections extracted from the tomographic inversions along profiles across hudson bay provide the first compelling direct evidence for crustal thinning beneath the basin our results are consistent with a recent estimate of 3 km of crustal thinning but not consistent with a proposed model for basin subsidence triggered by eclogitization of a remnant crustal root

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

processes leading to eclogitization densification of subducted and tectonically buried crust 1 the transformation of subducted and tectonically buried crustal rocks to denser eclogite plays a fundamental role in the dynamics of mountain building and crustal recycling however a complex of partially eclogitized granulites on the island of holsnoy in the western part of the norwegian caledonides reveals that such densification depends in part on the antecedent history of rock masses and that large bodies of untransformed rock can persist metastably even after long residence times in the lower crust the rocks on holsnoy suggest that conversion to eclogite was delayed until lower or subcrustal seismic events allowed aqueous fluids to enter the previously dry and unusually strong granulite complex metamorphism then occurred in a spatially heterogeneous manner with several distinct physical processes involving feedbacks between deformation fluid infiltration and chemical reactions operating simultaneously in different parts of the rock mass field relations show that the introduction of fluids and conversion to eclogite significantly weakened the rocks a reservoir flux systems model is used to represent the various processes contributing to eclogitization of the granulites which operated at vastly different rates over disparate intervals of time the model suggests that the metamorphic process may have been brief 1 myr and ultimately self limiting arrested by the change in rheology associated with the conversion of brittle granulite to ductile eclogite

organic facies variations source rock potential and sea level changes in cretaceous black shales of the quebrada ocal upper magdalena valley colombia a 290 m thick middle cretaceous black shale sequence in the upper magdalena valley a present day intramontane basin located between the central and eastern cordilleras of colombia was investigated with organic geochemical and microscopic analyses as a result of the investigation we were able to 1 differentiate four organic facies types 2 estimate their source rock potential and 3 integrate these facies into a sequence stratigraphic framework the four organic facies types were type c bc b and d type c contains a distinct terrigenous organic matter component in lowstand or highstand deposits organic facies type bc is characterized by an increase and a better preservation of marine organic matter bc belongs to the lower part of the transgressive systems tract sediments of organic facies type b have the highest amount of marine organic matter due to excellent preservation under anoxic conditions the absence of bioturbation and the enrichment of trace metals are further implications for deposition under anoxic conditions facies type b is found in the upper part of the transgressive systems tract and contains the best petroleum source rock potential facies b occurrence coincides with sea level highstand and correlates especially with a maximum flooding in northern south america during the turonian organic facies type d is also related to highstand deposits but shows a high rate of reworking and degradation of organic matter

imaging the upper crust of the korean peninsula by surface wave tomography cross correlation of seismic background motions campillo and paul 2003 shapiro et al 2005 is applied to observations from the korean meteorological administration seismic network to estimate the short period rayleigh and love wave dispersion characteristics of the region standard processing procedures are applied to the cross correlation except that signal whitening is used in place of one bit sampling to equalize power in signals from different times multiple filter analysis is used to extract the group velocities from the estimated green s functions which are then used to image the spatially varying dispersion at periods between 0 5 and 20 sec the tomographic inversion technique used inverts all periods simultaneously to provide a smooth dispersion curve as a function of period in addition to the usual smooth spatial image for a given period the gyeongsang basin in the southeastern part of the peninsula is clearly resolved with lower group velocities

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

stress accumulation in the marmara sea estimated through ground motion simulations from dynamic rupture scenarios we compare ground motions simulated from dynamic rupture scenarios for the seismic gap along the north anatolian fault under the marmara sea turkey to estimates from empirical ground motion prediction equations gmpes ground motions are simulated using a finite difference method and a 3d model of the local crustal structure they are analyzed at more than a thousand locations in terms of horizontal peak ground velocity characteristics of probable earthquake scenarios are strongly dependent on the hypothesized level of accumulated stress in terms of a normalized stress parameter t aochi and ulrich 2015 with respect to the gmpes it is found that simulations for many scenarios systematically overestimate the ground motions at all distances simulations for only some scenarios corresponding to moderate stress accumulation match the estimates from the gmpes the difference between the simulations and the gmpes is used to quantify the relative probabilities of each scenario and therefore to revise the probability of the stress field a magnitude mw7 operating at moderate prestress field 0 6 t 0 7 is statistically more probable as previously assumed in the logic tree of probabilistic assessment of rupture scenarios this approach of revising the mechanical hypothesis by means of comparison to an empirical statistical model e g a gmpe is useful not only for practical seismic hazard assessments but also to understand crustal dynamics

test of goodness of the nga ground motion equations to predict the strong motions of the 2012 ahar varzaghan dual earthquakes in northwestern iran in the first part of this study a set of 87 ground motion records with closest distance to the rupture plane r rup less than 200 km and averaged shear wave velocity over the top 30 m of the subsurface v s 30 between 175 and 1400 m s recorded during the 2012 ahar varzaghan dual earthquakes m w1 6 4 m w2 6 3 were taken into account to examine the predictive capabilities of the next generation attenuation nga ground motion prediction equations gmpes via a set of comparative analyses and tests the first applied method to assess the performance of the nga gmpes is based on the intraevent residual analysis the primary database i e 87 records was also used to develop an event specific gmpe in the case of the ahar varzaghan dual earthquakes by means of regression analyses the derived event specific gmpe has been compared with the nga gmpes for two different site conditions that is v s 30 375 m s rock site and v s 30 375 m s soil site the residual analysis results indicate that the nga gmpes perform better in predicting data recorded at rock sites compared to soil sites for soil sites and at large periods t 2 0 s the observed spectral accelerations are overpredicted by the nga gmpes furthermore as the second part of this study to select the most adequate gmpes 14 strong motion records from the 1997 ardebil earthquake m w 6 1 were added to the primary database the implementation of the likelihood lh and log likelihood methods as modern lh based ranking assessment techniques as well as the nash sutcliffe index reveal that the nga gmpes show good compatibility at short medium periods t 1 0 s on the basis of the data recorded during the 2012 ahar varzaghan dual and 1997 ardebil earthquakes i e 101 records however in the long period range the dispersion in the data does not allow the authors to draw a comprehensible conclusion

region specific seismic hazard analysis of krishna raja sagara dam india abstract region specific seismic hazard analysis was carried out for krishna raja sagara dam site in karnataka india seismic event data and seismic source data within a 500 km radius were collected deterministic seismic hazard analysis was conducted for different methods of earthquake magnitude and location estimation it was observed that the ground motion estimates vary widely with different methods of mmax estimation and that the rupture based method which calculates mmax based on fault dimensions can give a reliable estimate of the possible maximum magnitude in regions of low to moderate seismicity based on this study the greatest median ground motion at the dam site is estimated as 0 43 g and the ground motion required to be tolerated without catastrophic failure is considered as 0 11 g in stable continental regions across the world where earthquake data is scarce the methodology followed here can be adopted to conduct region specific seismic hazard analysis

a comparison of nga ground motion prediction equations to italian data abstract ground motion prediction equations gmpes have recently been developed in the next generation attenuation nga project for application to shallow crustal earthquakes in tectonically active regions we investigate the compatibility of those models with respect to magnitude scaling distance scaling and site scaling implied by italian strong motion data this is of interest because 1 the italian data are principally from earthquakes in extensional regions that are poorly represented in the nga dataset and 2 past practice in italy has been to use local gmpes based on limited datasets that cannot resolve many significant source path and site effects we find that the magnitude scaling implied by the italian data is compatible with four nga relations however the italian data attenuate faster than implied by the four ngagmpes at short periods the differences are statistically significant comparison with the fifth one was not possible because it was developed for rock conditions only three regression coefficients are reevaluated for the four ngagmpes to reflect the faster attenuation a constant term a term controlling the slope of distance attenuation and a source fictitious depth term the scaling of ground motion with respect to site shear wave velocity is consistent between the nga models and italian data moreover the data are found to contain a nonlinear site effect that is generally compatible with nga site terms the intraevent scatter of italian data is higher than in the nga models although interevent scatter is comparable to nga recommendations when the faster distance attenuation is considered on the basis of these findings we recommend using the nga relations with the aforementioned minor modifications to evaluate ground motions for seismic hazard analysis in italy

representative seismic hazard map of coimbatore india the seismic hazard value of any region depends upon three important components such as probable earthquake location maximum earthquake magnitude and the attenuation equation this paper presents a representative way of estimating these three important components considering region specific seismotectonic features rupture based seismic hazard analysis rbsha given by anbazhagan et al 2011 is used to determine the probable future earthquake locations this approach is verified on the earthquake data of bhuj region the probable earthquake location for this region is identified considering earthquake data till the year 2000 these identified locations match well with the reported locations after 2000 the further coimbatore city is selected as the study area to develop a representative seismic hazard map using rbsha approach and to compare with deterministic seismic hazard analysis probable future earthquake zones for coimbatore are located considering the rupture phenomenon as per energy release theory discussed by anbazhagan et at 2011 rupture character of the region has been established by estimating the subsurface rupture length of each source and normalized with respect to the length of the source average rupture length of the source with respect to its total length is found to be similar for most of the sources in the region which is called as the rupture character of the region maximum magnitudes of probable zones are estimated considering seismic sources close by and regional rupture character established representative gmpes for the study area have been selected by carrying out efficacy test through an average log likelihood value llh as ranking estimator and considering the isoseismal map new seismic hazard map of coimbatore has been developed using the above regional representative parameters of probable earthquake locations maximum earthquake magnitude and best suitable gmpes the new hazard map gives acceleration values at bedrock for maximum possible earthquakes these results are compared with deterministic seismic hazard map and recently published probabilistic seismic hazard values c 2014 elsevier b v all rights reserved

a predictive equation for vertical to horizontal response spectral ratios in northern iran abstract the importance of the vertical component of ground motion in damage infliction on a variety of structural systems has been shown in recent years however the available models for ground motion prediction equations gmpes for this component of earthquakes are limited and most of the existing gmpes have been specifically developed for the horizontal component of ground motion alternatively in some cases it is proposed to scale the horizontal spectrum of the earthquake to the vertical one using vertical to horizontal response spectral ratios vhsrs in this work the applicability of some global and regional vhsr models for northern iran are evaluated using several existing statistical approaches the results of these evaluations show inadequate correlation between these models and the observed vhsrs in this region consequently a new vhsr model has been proposed to convert the horizontal earthquake spectrum to the vertical one in the studied region in order to determine the regression coefficients for the proposed vhsr model some 712 three component records with distances less than 300 km from the source from 79 earthquakes with the magnitude ranging from m w 4 1 to 7 3 were used regression coefficients for peak ground acceleration and pseudospectral acceleration for 5 damped systems are determined using a random effect approach a series of comparative studies on the proposed model with respect to the existing vhsrs was performed using the median residuals for the spectral periods in the 0 1 3 s range the results of such investigation show significant reduction of the variability for the proposed model at least 50 compared with the other vhsrs online material database of strong motion records

guidelines for evaluating petroleum source rock using programmed pyrolysis rock eval pyrolysis is used to rapidly evaluate the petroleum generative potential and thermal maturity of rocks accurate conclusions require programs every 30 60 ft 9 18 m understanding of interpretive pitfalls and supporting data such as visual kerogen vitrinite reflectance and elemental analyses the generative potential of coals is commonly overestimated by pyrolysis and is best determined by elemental analysis and organic petrography most coals show high s2 s3 5 and low hi values 300 mg hc g toc migrated oil and mud additives which alter rock eval data can sometimes be removed by special processing for immature rocks bimodal s2 peaks and pi values over 0 2 indicate contamination pyrolysis downgrades organic poor clay rich rocks which show lower hi and higher tmax values than isolated kerogen because of adsorption of pyrolyzate on the clays tmax values for small s2 peaks 0 2 mg hc g toc are unreliable tmax is affected by maturation organic matter type contamination and the mineral matrix s3 is sensitive to inorganic and adsorbed carbon dioxide and to instrumentation problems acidification of carbonate rich samples and proper maintenance improves s3 measurement constant sample weights 100 mg are recommended below a threshold weight tmax increases by up to 10 c and other parameters decrease organic rich samples which overload the detector can be diluted with carbonate detector linearity is determined by pyrolyzing various weights of an organic rich rock

generation and migration of hydrocarbons in the maracaibo basin venezuela an integrated basin study abstract the history of hydrocarbon generation and migration in the maracaibo basin venezuela is closely related to its stratigraphic structural and tectonic evolution during the cretaceous and cenozoic times geochemical evaluation of the possible source rocks within the cretaceous and the tertiary sequences indicates that the argillaceous limestones and calcareous shales of the la luna formation cenomanian coniacian are the most important source rocks in the basin these rocks contain organic carbon ranging from 1 5 to 9 6 c original toc 2 5 10 8 have fluorescent amorphous marine type ii organic matter oil prone and have in the immature stage a h index of 700 mg hc g toc and a h c ratio of 1 5 the beginning of the oil window in these rocks occurs at a relatively low thermal maturity lopatin tti about 10 and the peak of oil generation corresponds to a tti value of 35 geochemistry of oils from the different reservoirs cretaceous paleocene eocene and miocene beds and oil oil and oil source rock correlation studies based on biomarkers have identified three genetic types of oil in the basin a marine type essentially derived from the la luna source a terrestrial type possibly originating either from the cretaceous lisure shales or the paleocene shales and a third type derived from the mixing of the first two types the marine type oil is distributed extensively throughout the basin whereas the terrestrial as well as the mixed marine and terrestrial types are found only in the southwestern part of the basin the marine type oils have been further subdivided based on their alteration and maturity reconstruction of the hydrocarbon generating areas at different geological times using tti maturity diagrams indicates that the generation of oil and gas in the basin took place during two periods the first phase occured during the middle to upper eocene times in the northeastern part of the basin while the second phase occured during the upper miocene to recent times in the central western and southern parts of the basin based on organic geochemical and sedimentological characteristics it is proposed that primary migration of oil from the la luna source rocks took place by expulsion of hydrocarbons through abundant microfractures developed by the pore fluid overpressure during hydrocarbon generation mass balance considerations suggest that the expulsion probably occurred as a hydrocarbon single phase and the expulsion efficiency for oil in la luna source rocks should have been very high 30 50 taking into consideration the development of oil and gas kitchens through time the paleostructures at the time of hydrocarbon generation and the characteristics of oils the migration history of the oil and gas generated from the la luna source has been outlined mixing of oils derived at different times eocene and miocene recent from the la luna source of different areas appeared to have taken place in block iv block 11 lago lamar motatan and bolivar coastal fields

depositional environment and source rock potential of miocene strata from the central fram strait introduction of a new computing tool for simulating organic facies variations abstract organic rich sediments were recognized in early miocene strata from the norwegian greenland sea during odp leg 151 three organic geochemical subunits were distinguished in hole 909c using detailed organic geochemical and microscopic analyses toc up to 3 wt hi up to 200 mg hc g toc and 13corg values 24 26 indicate the predominance of terrestrial type iii organic matter in subunit 3 18 16 2 ma biomarker and vitrinite reflectance values r0 0 5 point to rather fresh immature terrestrial organic matter supplied by river discharge from adjacent vegetated coastal areas although the sediments of subunit 3 have a fair to good source rock potential they are insufficiently mature to generate significant amounts of oil or gas to test if the moderate generation potential and source rock quality of subunit 3 are applicable to the entire area the computer software of mod was applied several modelling runs testing the most probable depositional scenarios result even under conservative assumptions in the formation of good to excellent source rocks towards the basin margins

organic matter accumulation in the oil shale and coal bearing huadian basin eocene ne china abstract the huadian basin located in northeastern china is a fault controlled basin filled by eocene non marine sediments assigned to the huadian formation the formation is subdivided from bottom to top into three members pyrite member oil shale member and carbonaceous shale member using bulk geochemical data from borehole hd3 and core descriptions from a high number of wells the factors controlling organic matter accumulation have been evaluated the organic matter content of the pyrite member is relatively low average toc 0 9 wt mudstones deposited in shallow lacustrine environments contain between 1 and 2 wt toc max 6 wt and a kerogen type ii hi 400 600 mg hc g toc an arid climate prevented the accumulation of thick coal the overlying oil shale member contains 13 oil shale layers which are mined underground the oil shale member has been interpreted as a 3rd order sequence significant differences exist between oil shales deposited in different systems tracts 2 m thick coaly oil shale of low quality oil yield 3 5 wt developed in the lowstand systems tract oil shale up to 7 m thick of moderate quality oil yield 4 1 8 0 wt was deposited during the transgressive systems tract tst thinner the carbonaceous shale member representing the balanced fill to overfilled stage of basin evolution hosts economic coal seams which are occasionally accompanied by shallow lacustrine shales with abundant hydrogen rich organic matter otherwise non coal layers are typically low in organic matter average toc 0 9 wt in contrast to the huadian basin a very thick coal seam overlain by a single oil shale layer more than 100 m thick developed in the eocene fushun basin this indicates major differences in the evolution of basins with similar tectonic setting and age

trans hudson orogen of north america and himalaya karakoram tibetan orogen of asia structural and thermal characteristics of the lower and upper plates 1 the trans hudson orogen tho of north america and the himalaya karakoram tibetan orogen hkto of asia preserve a paleoproterozoic and cenozoic record respectively of continent continent collision that is notably similar in scale duration and character in tho the tectonothermal evolution of the lower plate involves 1 early thin skinned thrusting and barrovian metamorphism 2 out of sequence thrusting and high t metamorphism and 3 fluid localized reequilibration anatexis and leucogranite formation the crustal evolution of the indian lower plate in hkto involves 1 early subduction of continental crust to ultrahigh pressure uhp eclogite depths 2 regional barrovian metamorphism and 3 widespread high t metamorphism anatexis and leucogranite formation the shallow depths of the high t metamorphism in hkto are consistent with early to mid miocene ductile flow of an indian lower plate midcrustal channel from beneath the southern tibetan plateau to the greater himalaya melt weakening of the lower plate in tho is not observed at a similar scale probably due to the paucity of pelitic lithologies tectonothermal events in the upper plate of both orogens include precollisional accretion of crustal blocks emplacement of andean type plutonic suites and high t metamorphism syncollisional to postcollisional events include emplacement of garnet biotite muscovite leucogranites anatectic granites and sporadic metamorphism up to 90 myr following the onset of collision in tho comparing the type and duration of tectonothermal events for tho and hkto supports the notion of tectonic uniformitarianism for at least the later half of dated earth history and highlights the complementary nature of the rock record in an older exhumed orogen compared to one undergoing present day orogenesis

quaternary exhumation history of the ne tibetan plateau revealed by peculiar distributions of polycyclic aromatic hydrocarbons in core extracts from the sanhu depression eastern qaidam basin

evidence of bias in estimations of earthquake size magnitudes of earthquakes determined using traditional methods show systematic deviations dependent on tectonic setting from accurate estimates of earthquake size magnitudes are overestimated for most of the continental earthquakes underestimated for mid oceanic ridges and differences of varying sign are obtained for subduction zones this is important in evaluating the seismic risk or consideration of effects such as the seismic versus aseismic strain release as seismic moments determined from magnitudes can be wrong by as much as a factor of four

organic rich transitional facies in silled basins response to sea level change high resolution profiles of organic carbon delta sup 13 c sub org sulfur delta sup 38 s and some trace elements in cores from two silled basins kau bay indonesia and the black sea allow division of the sedimentary record into three distinct units representing a pleistocene fresh water brackish water facies unit 3 a holocene transitional facies unit 2 and a modern fully marine facies unit 1 the geochemical characteristics of these units are strikingly similar for both basins the sediments form unit 3 are characterized by the predominance of terrestrial organic matter mo and u concentrations at crustal abundance and positive delta sup 34 s values the transitional sediments unit 2 are strongly enriched in marine organic matter and mo v and u and have intermediate delta sup 34 s values sediments from the modern marine facies unit 1 are moderately organic carbon rich and slightly enriched in mo and u and have negative delta sup 34 s values the organic carbon rich sediments from unit 2 were formed by increased production during the transition from the pleistocene isolated fresh water brackish water environment to the modern open marine facies this temporarily higher productivity was caused by displacement of nutrients from the deep water into the euphotic zone owing to the gradual infilling by marine waters

model validations and comparisons of the next generation attenuation of ground motions nga west project abstract the earthquake ground motion prediction equations developed for the next generation attenuation of ground motions nga west project in 2008 have established a new baseline for the estimation of ground motion parameters such as peak ground acceleration peak ground velocity and spectral acceleration for shallow crustal earthquakes in active tectonic regions we perform statistical goodness of fit analyses to quantitatively compare the predictive capabilities of the nga models and their predecessors using several testing subsets of the master database used in model development in addition we perform a blind comparison test using 1060 ground motion records from seven recent earthquakes recorded in california the 2003 m 6 5 san simeon event 2004 m 6 0 parkfield event 2005 m 5 2 anza event 2007 m 5 4 alum rock event 2008 m 5 4 chino hills event 2010 m 7 2 baja event and 2010 m 5 7 ocotillo event we assess how modeling decisions regarding the regression dataset functional forms input parameters and model complexity influence the models predictive capabilities by comparing the performance of each model we discuss various ground motion modeling strategies and offer recommendations for model development we find that increased model complexity does not necessarily lead to increased prediction accuracy that the inclusion of aftershocks in regression datasets may result in decreased predictive capabilities for mainshocks and that the use of measured site characteristics leads to greatly improved ground motion predictions a model validation framework is introduced to assess the prediction accuracy of ground motion prediction equations and to aid in their future development

observations on regional variability in ground motion amplitudes for small to moderate earthquakes in north america abstract the regional variability in earthquake ground motion amplitudes for a given magnitude and distance in western north american environments was examined using shakemap data from small to moderate events the abundance of data for small to moderate events in california allows average ground motion levels as a function of magnitude and distance to be resolved with a high level of confidence ground motion amplitudes in northern california are lower on average than those for southern california for events of the same magnitude at distances in the range from 120 to 250 km over all frequencies the observed regional variations could be indicative of regional differences in attenuation effects or site effects an unexpected result of the study is the finding that ground motions for events of m m m m

earth s gravitational field seismic tomography resolves the enigma of the laurentian anomaly we demonstrate that the negative free air gravity anomaly over hudson bay is not due to glacial isostatic disequilibrium but rather to the influence of large scale mantle convection

precambrian crustal evolution seismic constraints from the canadian shield whether or not plate tectonic processes operated on a younger hotter earth remains ambiguous seismic data from new networks in the hudson bay region of the canadian shield where the precambrian geological record spans more than 2 billion years offer fresh scope to address this problem using receiver function analyses we show that the crust of the rae domain which exhibits ages of paleo to neoarchean 3 9 2 7 ga is likely felsic to intermediate in composition average vp vs 1 73 and seismically transparent with a sharp moho there is little evidence for modern style plate tectonics and based on the simplicity and spatial extent of the felsic crust models favouring vertical tectonic processes such as crustal delamination or plume activity appear better suited to the results data from the hearne domain which exhibits widespread 2 7 ga granite and greenstone geology show a more complex crust with higher vp vs ratios consistent with a greater mafic component the trans hudson orogen tho proposed to be a himalayan scale mountain belt during the paleoproterozoic is thought to have formed during the 1 8 ga collision of the superior and churchill plates results from the quebec baffin island segment of the tho appear to map out the first order shape of the underthrusting superior plate with elevated vp vs ratios likely representing the rifted margin of the superior craton consistently thicker crust is observed beneath central and southern baffin island 43 km coincident with widespread high grade metamorphic surface geology these features can be explained by crustal thickening due to stacking of accreted terranes during continent continent collision analogous to the present day tibetan plateau followed by erosion when reviewed in light of age and compositional constraints from the geological record our seismic observations point towards secular crustal evolution from non plate tectonic during the paleo to mesoarchean evolving towards fully developed modern style plate tectonics during the paleoproterozoic

testing the global applicability of ground motion prediction equations for active shallow crustal regions abstract large research initiatives such as the global earthquake model gem or the seismic hazard harmonization in europe share projects concentrate a great collaborative effort on defining a global standard for seismic hazard estimations in this context there is an increasing need for identifying ground motion prediction equations gmpes that can be applied at both global and regional scale with increasing amounts of strong motion records that are now available worldwide observational data can provide a valuable resource to tackle this question using the global dataset of allen and wald 2009 we evaluate the ability of 11 gmpes to predict ground motion in different active shallow crustal regions worldwide adopting the approach of scherbaum et al 2009 we rank these gmpes according to their likelihood of having generated the data in particular we estimate how strongly data support or reject the models with respect to the state of noninformativeness defined by a uniform weighting such rankings derived from this particular global dataset enable us to explore the potential of gmpes to predict ground motions in their host region and also in other regions depending on the magnitude and distance considered in the ranking process we particularly focus on the influence of the distribution of the testing dataset compared with the gmpe s native dataset one of the results of this study is that some nonindigenous models present a high degree of consistency with the data from a target region two models in particular demonstrated a strong power of geographically wide applicability in different geographic regions with respect to the testing dataset the models of akkar and bommer 2010 and chiou et al 2010

attenuation relations of strong ground motion in japan using site classification based on predominant period a spectral acceleration attenuation model for japan is presented in the present study the data set includes a very large number of strong ground motion records up to the 2003 off tokach main and aftershocks site class terms instead of individual site correction terms are used the site classes of recording stations are from a recent study on site classification for strong motion recording stations in japan according to a classification scheme that has been used in japanese engineering design the use of site class terms enables tectonic source type effects to be identified and accounted for in the present model the effects of a faulting mechanism for crustal earthquakes also are accounted for for crustal and interface earthquakes a simple form of an attenuation model with respect to distance is able to capture the main strong motion characteristics and achieves unbiased estimates for subduction slab events a simple distance modification factor is employed to achieve plausible and unbiased predictions the effects of source depth tectonic source type and faulting mechanism of crustal earthquakes are significant the need for magnitude squared terms is evaluated and the use of magnitude squared terms reduces the interevent error further

precambrian plate tectonics seismic evidence from northern hudson bay canada the canadian shield is one of the largest exposures of precambrian rocks on earth it is a mosaic of several archean terranes that were brought together during a series of paleoproterozoic orogens culminating in the so called trans hudson orogen which is thought to have been similar to the himalayan orogen in scale and nature the tectonic evolution and lithospheric subdivisions of this region are poorly understood but new seismic networks in northern hudson bay provide fresh opportunity to place constraints on the precambrian processes that formed and shaped it we show via a study of seismic anisotropy that the lithosphere of the northern hudson bay region retains a strong signature of archean paleoproterozoic tectonics we map the boundary between the upper churchill and lower superior plates that collided ca 1 8 ga and identify back azimuth dependent splitting parameters t on baffin island that indicate complex anisotropy e g dipping fabric beneath the region our results support the view that significant lithospheric deformation occurred during the paleoproterozoic and that modern day plate tectonic processes were thus in operation by at least ca 1 8 ga

controls on c s ratios in hemipelagic upwelling sediments the relationship between organic carbon and reduced sulfur concentrations was investigated in hemipelagic sediments underlying highly productive regions of the ocean and oxic to suboxic waters the benguela upwelling area peru and oman margins at all three sites the degree of pyritization averaged close to 0 4 indicating that reactive iron was probably not limiting for pyrite formation complete sulfate reduction occurred in the upper sections of the sediments from the oman and peru margins however dissolved sulfate never decreased below 5 mm in the benguela upwelling sediments the authors attribute this to more advanced organic matter degradation at the benguela upwelling site c s ratios increased with increasing organic carbon concentrations at all sites for sediments with greater than 3 wt toc the c s ratio averaged about 1 3 and 1 8 times the normal marine ratio of 2 8 at the benguela upwelling and peru margin sites respectively but 2 9 times this value in the oman margin sediments they hypothesize that the quality of the organic matter undergoing burial and rates of near interfacial transport processes are the dominant controls on sulfur burial in these sediments

an evaluation of the applicability of nga west2 ground motion models for japan and new zealandan evaluation of the applicability of nga west2 gmms for japan and new zealand

phase changes and thermal subsidence in intracontinental sedimentary basins summary a model of tectonic subsidence is developed to explain the late acceleration of subsidence observed in some intracratonic sedimentary basins the proposed mechanism combines the effect of thermal contraction of an initially hot lithosphere with the effect of a subcrustal phase transformation that moves under changing pressure and temperature conditions the subsidence following a sudden change in temperature at the base of the lithosphere is calculated the calculations show that 1 phase changes if present and activated contribute substantially to the subsidence of sedimentary basins 2 because the effect of phase change is delayed subsidence accelerates after a time on the order of 20 myr and 3 the duration of the subsidence is on the order of 100 to 150 myr during the late stages of subsidence the phase change is the dominating mechanism an application to the michigan basin is presented the calculated sediment accumulation history fits the record well when the effect of sea level changes is included in the model

phanerozoic vertical motions of hudson bay we analyze the sedimentary record of the hudson bay basin an intracratonic basin which is widely believed to have been formed by convective downwelling within the mantle this belief largely stems from the coincidence of a long wavelength negative gravity anomaly and an approximately circular basin which is filled with about 2 km of predominantly paleozoic sedimentary rocks our starting point is a set of wells and seismic reflection profiles which demonstrate that the basin subsided rapidly from ordovician to devonian times one and two dimensional subsidence modeling show that water loaded subsidence occurred in two stages and is too rapid to be accounted for by thermal contraction alone instead we suggest that basin subsidence is consistent with minor phases of lithospheric thinning which occurred during ordovician silurian and early middle devonian times stretching factors for these minor extensional episodes vary from 1 05 to 1 2 with vertical strain rates of 2 10 ga 1 our interpretation of the

a 210 000 year record of barium variability in the deep northwest atlantic ocean the deep ocean is the storehouse for most of the carbon and nutrients in the ocean atmosphere system together with its out crops at high latitudes the deep ocean is of great importance in driving glacial interglacial changes in the carbon dioxide content of the atmosphere1 3 the chemical and physical structure of the deep glacial oceans can be reconstructed by means of palaeochemical tracers for example the cadmium and carbon isotope contents of benthic foraminifera have been used to reconstruct the phosphate or labile nutrient compositions of deep waters4 14 recently it was proposed15 that barium in benthic foraminifera could be used to reconstruct the distribution of refractory deep regenerated chemical properties in the water masses of the glacial oceans a reconstruction of barium concentra tions in the oceans at the time of the last glacial maximum revealed the greatest changes in the north atlantic where barium concentrations in deep water were up to 50 higher than at present16 here we present a record of the benthic ba ca ratio in the deep northwest atlantic stretching back to interglacial stage 7 210 kyr ago encompassing two full glacial cycles a comparison of the barium record with that of the other nutrient like tracers lends confidence in the general agreement between these tracers while showing some spectral variability unique to barium thus underscoring its utility as an additional palaeoceanographic tracer

a comparison between the forecast by the united states national seismic hazard maps with recent ground motion records confidence in scientific models accumulates by continuously validating the model s predictions by observations we compared the seismic hazard forecasts of the four published versions of the u s geological survey national seismic hazard maps with observed ground motions a large dataset is necessary for a statistically meaningful comparison and so our comparison was based on an aggregated approach such that the observations and the forecast in a region california and the central and eastern united states ceus were combined and compared as a whole we used instrumental records in california and macroseismic intensity in the ceus since 2000 as the observation which was largely prospective to the hazard maps we verified that the observed seismic hazard based on macroseismic intensity was consistent with that based on instrumental records making model evaluation in the ceus for which instrumental records were almost nonexistent viable the observed hazard was found to be generally consistent with the forecasted one for peak ground acceleration pga in california and for both pga and spectral acceleration at 1 s sa1 in the ceus forecasted hazard for sa1 for california appeared to be conservative recent versions of the hazard map were in better agreement with observations in california small earthquakes as expected were found to have insignificant impact on sa1 induced earthquakes in the ceus have increased the observed seismic hazard but did not invalidate the hazard model as a whole we examined the resolving power of the test by computing its statistical power

the subsidence of the williston basin a detailed comparison between the pre cretaceous stratigraphic record in the williston basin and the available information about phanerozoic sea level changes indicates that most stratigraphic breaks in the basin reflect eustatic control the basin appears to have been subsiding continuously and steadily about the same centre for most of the phanerozoic above a thick 55 km continental crust deposition kept up with subsidence and most of the sedimentary record was laid down close to sea level erosional breaks in the stratigraphic record may represent periods of removal of strata during episodes of low sea level a possible explanation of this essentially steady nonexponential subsidence record is that a mafic subcrustal body is undergoing transformation to eclogite

cyclic phosphate rich successions in the upper cretaceous of colombia abstract upper cretaceous neritic to hemipelagic successions from the eastern colombian cordillera display frequent and rhythmic intercalations of phosphate rich sediment their accumulation is attributed to a back arc setting between the andean arctrench system and the guayana cratonic shield in three examined sections near tausa tunja and iza all north of bogota respectively the phosphate rich sediments occur in 1 15 m thick coarsening upward series ideally consisting from the base to the top of porcelanite organic rich claystone siltstone sandstone and a condensed and thoroughly burrowed top bed phosphatic particles appear either in thin gravity flow deposits or in pristine in situ occurrences near the base of these successions intercalated in fine grained biosiliceous or clay rich sediment or in the condensed top bed the major portion of this coarsening upward series porcelanite to sandstone is considered a shallowing upward succession and the thin condensed phosphatic top bed a deepening upward succession these rhythmic successions are interpreted as parasequences resulting from fourth order relative sea level changes based upon biostratigraphic age estimates the time span of formation of these parasequences range between approximately 100 000 and 200 00 yr the allochthonous phosphate intercalations near the base of the parasequences are derived from condensed phosphatic top beds which may have been exposed at the sediment water interface in proximal directions this suggests that the parasequence boundaries i e marine flooding surfaces are diachronous and become younger in onshore directions using the vertical stacking patterns of these parasequences we distinguish between transgressive and highstand systems tracts tst and hst tst s are characterized by the dominance of phosphatic sediment laminated and organic rich claystone and laminated porcelanite this suite of sediments documents high nutrient fluxes and the presence of an oxygen minimum zone both probably induced by coastal upwelling hst s include laminated to well bioturbated siliciclastic successions which may reflect a weakening or basinward shift of upwelling cells and higher levles of bottom water oxygenation the dominance of siliciclastics in hst s is indicative of high detrital fluxes which outpaced sediment accomodation rates on the shelf upper campanian ammonoids have been found in three levels of the lower plaeners member of the guadalupe formation in the section near tausa nostoceras nostoceras liratum sp n exiteloceras jenneyi whitfield 1887 and libycoceras sp e jenneyi is an important zonal marker in the u s western interior that is also known from the basal mount laurel sand of delaware usa its occurrence at tausa is the first record outside the usa and provides an important datum for intercontinental correlation the type of libycoceras sp encountered in tausa is also known from the upper campanian of peru and angola together with the presence of andalusiella polymorphia malloy 1972 a dinoflagellate cyst an age range is given for the formation of the lower plaeners member at tausa late campanian to early maastrichtian

accounting for fault roughness in pseudo dynamic ground motion simulations geological faults comprise large scale segmentation and small scale roughness these multi scale geometrical complexities determine the dynamics of the earthquake rupture process and therefore affect the radiated seismic wavefield in this study we examine how different parameterizations of fault roughness lead to variability in the rupture evolution and the resulting near fault ground motions rupture incoherence naturally induced by fault roughness generates high frequency radiation that follows an 2 decay in displacement amplitude spectra because dynamic rupture simulations are computationally expensive we test several kinematic source approximations designed to emulate the observed dynamic behavior when simplifying the rough fault geometry we find that perturbations in local moment tensor orientation are important while perturbations in local source location are not thus a planar fault can be assumed if the local strike dip and rake are maintained we observe that dynamic rake angle variations are anti correlated with the local dip angles testing two parameterizations of dynamically consistent yoffe type source time function we show that the seismic wavefield of the approximated kinematic ruptures well reproduces the radiated seismic waves of the complete dynamic source process this finding opens a new avenue for an improved pseudo dynamic source characterization that captures the effects of fault roughness on earthquake rupture evolution by including also the correlations between kinematic source parameters we outline a new pseudo dynamic rupture modeling approach for broadband ground motion simulation

a local ground motion predictive model for turkey and its comparison with other regional and global ground motion models we examined the differences between the ground motion estimations of local and global prediction equations and explored some seismological parameters that may explain these differences to achieve this objective we first derived a set of ground motion prediction equations gmpes for estimating peak horizontal accel eration velocity and pseudospectral acceleration using the recently compiled turkish ground motion database the new gmpes are comparable with the recent global gmpes in terms of model sophistication and they are based on a well studied national dataset using global gmpes from the next generation attenuation of ground motions project power et al 2008 and the pan european akkar and bommer 2010 model we observed that the discrepancy between local and global gmpes is more prominent at small magnitudes provided that the gmpes possess similar mag nitude limits our more detailed comparisons with the pan european akkar and bom mer 2010 predictive model as well as with the estimations from a combined italian and turkish accelerometric dataset indicate that depth can be of importance for delineating the differences between local and global gmpes