a catalog of felt intensity data for 570 earthquakes in india from 1636 to 2009 eight thousand three hundred thirty nine intensity observations have been evaluated for earthquakes that occurred on the indian subcontinent and surround ing plate boundaries from the seventeenth century to the present they characterize 570 earthquakes more than 90 of which occurred in the past two centuries the electronic supplement to this article lists these data using european macroseismic scale ems 98 intensities with their geographic coordinates we summarize these data graphically in the form of a spatially averaged intensity map for the subcontinent a map that emphasizes the features of many previously published earthquake hazard maps for the indian plate but which more faithfully depicts regional amplification and attenuation we also estimate the probable return time for future damaging shaking in five of india s largest cities

hybrid empirical ground motion prediction equations for eastern north america using nga models and updated seismological parameters in the field of earthquake engineering ground motion prediction models are frequently used to estimate the peak ground acceleration pga and the pseudos pectral acceleration psa in regions of the world where ground motion recordings are plentiful such as western north america wna the ground motion prediction equations are obtained using empirical methods in other regions such as eastern north america ena with insufficient ground motion data alternative methods must be used to develop ground motion prediction equations gmpes the hybrid empiri cal method is one such method used to develop ground motion prediction equations in areas with sparse ground motions this method employs the stochastic simulation method to adjust empirical gmpes developed for a region with abundant strong motion recordings in order to estimate strong motion parameters in a region with a sparse database the adjustments take into account differences in the earthquake source wave propagation and site response characteristics between the two regions in this study a hybrid empirical method is used to develop a new gmpe for ena using five new ground motion prediction models developed by the pacific earthquake engineering research center peer for wna a new ena gmpe is derived for a magnitude range of 5 to 8 and closest distances to the fault rupture up to 1000 km ground motion prediction equations are developed for the response spectra pseudoacceleration 5 damped and the pga for hard rock sites in ena the resulting ground motion prediction model developed in this study is compared with two ena ground motion models used in the 2008 national seismic hazard maps as well as with available observed data for ena

estimating seabed scattering mechanisms via bayesian model selection a quantitative inversion procedure is developed and applied to determine the dominant scattering mechanism surface roughness and or volume scattering from seabed scattering strength data the classification system is based on trans dimensional bayesian inversion with the deviance information criterion used to select the dominant scattering mechanism scattering is modeled using first order perturbation theory as due to one of three mechanisms interface scattering from a rough seafloor volume scattering from a heterogeneous sediment layer or mixed scattering combining both interface and volume scattering the classification system is applied to six simulated test cases where it correctly identifies the true dominant scattering mechanism as having greater support from the data in five cases the remaining case is indecisive the approach is also applied to measured backscatter strength data where volume scattering is determined as the dominant scattering mechanism comparison of inversion results with core data indicates the method yields both a reasonable volume heterogeneity size distribution and a good estimate of the sub bottom depths at which scatterers occur

site amplifications for generic rock sites seismic shear wave velocity as a function of depth for generic rock sites has been estimated from borehole data and studies of crustal velocities and these velocities have been used to compute frequency dependent amplifications for zero attenuation for use in simulations of strong ground motion we define a genetic rock site as one whose velocity at shallow depths equals the average of those from the rock sites sampled by the borehole data most of the boreholes are in populated areas for that reason the rock sites sampled are of particular engineering significance we consider two genetic rock sites rock corresponding to the bulk of the borehole data and very hard rock such as is found in glaciated regions in large areas of eastern north america or in portions of western north america the amplifications on rock sites can be in excess of 3 5 at high frequencies in contrast to the amplifications of less than 1 2 on very hard rock sites the consideration of unattenuated amplification alone is computationally convenient but what matters for ground motion estimation is the combined effect of amplification and attenuation for reasonable values of the attenuation parameter k 0 the combined effect of attenuation and amplification for rock sites peaks between about 2 and 5 hz with a maximum level of less than 1 8 the combined effect is about a factor of 1 5 at 1 hz and is less than unity for frequencies in the range of 10 to 20 hz depending on t using these amplifications we find provisional values of about ao 70 bars and k 0 0 035 sec for rock sites in western north america by fitting our empirically determined response spectra for an m 6 5 event to simulated values the borehole data yield shear velocities 033o of 618 and 306 rrdsec for rock and soil sites respectively when averaged over the upper 30 m from this we recommend that v30 equals 620 and 310 m sec for applications requiring the average velocity for rock and soil sites in western north america by combining the amplifications for rock sites and the site factors obtained from our analysis of strong motion data we derive amplifications for sites with 17 3o 520 m sec nehrp class c corresponding to a mix of rock and soil sites and v3o 310 and 255 m sec average soil and nehrp class d sites respectively for the average soil site the combined effect of amplification and attenuation exceeds a factor of 2 0 for frequencies between 0 4 and about 4 hz with a peak site effect of 2 4 the peak of the nehrp class d site effect is 2 7

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

transdimensional love wave tomography of the british isles and shear velocity structure of the east irish sea basin from ambient noise interferometry we present the first love wave group velocity and shear velocity maps of the british isles obtained from ambient noise interferometry and fully non linear inversion we computed interferometric inter station green s functions by cross correlating the transverse component of ambient noise records retrieved by 61 seismic stations across the uk and ireland group velocity measurements along each possible inter station path were obtained using frequency time analysis and converted into a series of inter station traveltime datasets between 4 and 15 seconds period traveltime uncertainties estimated from the standard deviation of dispersion curves constructed by stacking randomly selected subsets of daily cross correlations were observed to be too low to allow reasonable data fits to be obtained during tomography data uncertainties were therefore estimated again during the inversion as distance dependent functionals we produced love wave group velocity maps within 8 different period bands using a fully non linear tomography method which combines the transdimensional reversible jump markov chain monte carlo rj mcmc algorithm with an eikonal raytracer by modelling exact raypaths at each step of the markov chain we ensured that the non linear character of the inverse problem was fully and correctly accounted for between 4 and 10 seconds period the group velocity maps show remarkable agreement with the known geology of the british isles and correctly identify a number of low velocity sedimentary basins and high velocity features longer period maps in which most sedimentary basins are not visible are instead mainly representative of basement rocks in a second stage of our study we used the results of tomography to produce a series of love wave group velocity dispersion curves across a grid of geographical points focussed around the east irish sea sedimentary basin we then independently inverted each curve using a similar rj mcmc algorithm to obtain a series of one dimensional shear velocity profiles by merging all 1d profiles we created a fully three dimensional model of the crust beneath the east irish sea the depth to basement in this model compares well with that averaged from seismic reflection profiles this result is the first 3 dimensional model in the uk with fully quantified uncertainties it shows basin depths and basement structures and their concomitant uncertainties

buckle controlled seismogenic faulting in peninsular india as intraplate earthquakes are often not associated with major known faults their location as well as their timing is unpredictable in peninsular india the larger mx5 0 events occur mainly on reverse faults in a series of belts b400 km apart which are aligned roughly normal to the azimuth of convergence between the indian and eurasian plates the location of the belts is controlled largely by the buckling wavelength of the lithosphere and the seismogenic faults do not generate folding and sometimes result from it there is consequently no need to postulate the creation of regularly spaced normal faults in an antecedent extensional phase and the deformation is consistent with a plate driving force such as gravity glide which is unlikely to reverse its polarity and which creates structures that are influenced by plate geometry at the leading edge the thesis is potentially of value to seismic hazard mitigation as it identifies the zones that are most at risk r 2004 published by elsevier ltd

trans dimensional surface reconstruction with different classes of parameterization portions of this software development were funded by auscope through the national collaborative research infrastructure strategy ncris an australian federal government programme r h and t b are funded by the european unions horizon 2020 research and innovation programme under grant agreement 716542

empirical stochastic ground motion prediction for eastern north america an alternative approach based on a hybrid empirical model is utilized to predict the ground motion relationship for eastern north america ena in this approach a stochastic model is first used to derive modification factors from the ground motions in western north america wna to the ground motions in ena the ground motion parameters are then estimated to develop an empirical attenuation relationship for ena using empirical ground motion relationships from wna w e develop an empirical stochastic source model for both regions to obtain ground mo tions at different magnitude distance range of interest at short distances r 30 km and large magnitudes mw 6 4 an equivalent point source model is carried out to consider the effect of finite fault modeling on the ground motion parameters source focal depth and brune stress drop are assumed to be magnitude dependent we choose three well defined empirical attenuation relationships for wna to com pare the empirical ground motion processes between the two regions a composite functional attenuation form is defined and in turn a nonlinear regression analysis is performed by using a genetic algorithm ga for a wide range of magnitudes and distances to develop an empirical attenuation relationship from the stochastic ground motion estimates in ena the empirical stochastic attenuation relationship for hor izontal peak ground acceleration and spectral acceleration are applicable to earth quakes of mw 5 0 8 2 at distances of up to 1000 km the resulting attenuation model developed in this study is compared with those used in the 2002 national seismic hazard maps derived in the 2003 electric power research institute studies and re corded in ena the comparison of the results to the other attenuation functions and the available ena data show a reasonable agreement for the ena ground motions

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

bayesian inversion of marine csem data with a trans dimensional self parametrizing algorithm summary the posterior distribution of earth models that fit observed geophysical data convey information on the uncertainty with which they are resolved from another perspective the non uniqueness inherent in most geophysical inverse problems of interest can be quantified by examining the posterior model distribution converged upon by a bayesian inversion in this work we apply a reversible jump markov chain monte carlo method to sample the posterior model distribution for the anisotropic 1 d seafloor conductivity constrained by marine controlled source electromagnetic data unlike conventional gradient based inversion approaches our algorithm does not require any subjective choice of regularization parameter and it is self parametrizing and trans dimensional in that the number of interfaces with a resistivity contrast at depth is variable as are their positions a synthetic example demonstrates how the algorithm can be used to appraise the resolution capabilities of various electromagnetic field components for mapping a thin resistive reservoir buried beneath anisotropic conductive sediments a second example applies the method to survey data collected over the pluto gas field on the northwest australian shelf a benefit of our bayesian approach is that subsets of the posterior model probabilities can be selected to test various hypotheses about the model structure without requiring further inversions as examples the subset of model probabilities can be viewed for models only containing a certain number of layers or for models where resistive layers are present between a certain interval as suggested by other geological constraints such as seismic stratigraphy or nearby well logs

trans dimensional finite fault inversion summary this paper develops a probabilistic bayesian approach to the problem of inferring the spatiotemporal evolution of earthquake rupture on a fault surface from seismic data with rigorous uncertainty estimation to date uncertainties of rupture parameters are poorly understood and the effect of choices such as fault discretization on uncertainties has not been studied we show that model choice is fundamentally linked to uncertainty estimation and can have profound effects on results the approach developed here is based on a trans dimensional selfparametrizationofthefault avoidsregularizationconstraintsandprovidesrigorousuncertainty estimationthataccountsformodel selectionambiguityassociatedwiththefaultdiscretization in particular the fault is parametrized using self adapting irregular grids which intrinsically match the local resolving power of the data and provide parsimonious solutions requiring few parameters to capture complex rupture characteristics rupture causality is ensured by parametrizing rupture onset time by a rupture velocity field and obtaining first rupture times from the eikonal equation the bayesian sampling of the parameter space is implemented on a computer cluster with a highly efficient parallel tempering algorithm the inversion is applied to simulated and observed w phase waveforms from the 2010 maule chile earthquake simulation results show that our approach avoids both over and underparametrization to ensure unbiased inversion results with uncertainty estimates that are consistent with data information the simulation results also show the ability of w phase data to resolve the spatial variability of slip magnitude and rake angles in addition sensitivity to spatially dependent rupture velocities exists for kinematic slip models application to the observed data indicates that residual errors are highly correlated and likely dominated by theory error necessitating the iterative estimation of a non stationary data covariance matrix the moment magnitude for the maule earthquake is estimated to be 8 9 with slip concentrated in two zones updip of and north and south of the hypocentre respectively while this aspect of the slip distribution is similar to previous studies we show that the slip maximum in the southern zone is poorly resolved compared to the northern zone both slip maxima are higher than reported in previous studies which we speculate may be due to the lack of bias caused by the regularization used in other studies

moho depth of the british isles a probabilistic perspective summary we present a new moho depth model of the british isles and surrounding areas from the most up to date compilation of moho depth estimates obtained from refraction reflection and receiver function data we use a probabilistic trans dimensional and hierarchical approach for the surface reconstruction of moho topography this fully data driven approach allows for adaptive parametrization assessment of relative importance between different data types and uncertainties quantification on the reconstructed surface our results confirm the first order features of the moho topography obtained in previous work such as deeper moho 29 36 km in continental areas e g ireland and great britain and shallower moho 12 22 km offshore e g in the atlantic ocean west of ireland resolution is improved by including recent available data especially around the porcupine basin onshore ireland and great britain ne trending features in moho topography are highlighted above the rockall high about 28 km and the rockall trough with a ne directed deepening from 12 to about 20 km a perpendicular se oriented feature moho depth 26 28 km is located between the orkney and the shetland extending further sw in the north sea onshore our results highlight the crustal thinning toward the n in ireland and an e w oriented transition between deep 34 km and shallow about 28 km moho in scotland our probabilistic results are compared with previous models showing overall differences around 2 km within the posterior uncertainties calculated with our approach bigger differences are located where different data are used between models or in less constrained areas where posterior uncertainties are high

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

is there a link between geomagnetic reversal frequency and paleointensity a bayesian approach over the last 25 years several studies have tested for a link between geomagnetic field intensity and reversal frequency however despite a large increase in the number of absolute paleointensity determinations and improved methods for obtaining such data two competing models have arisen here we employ a new tool for objectively analyzing paleomagnetic time series to investigate the possibility of a link between reversal frequency and paleointensity transdimensional markov chain monte carlo techniques are applied to a quality filtered version of the global paleointensity pint database for the last 202 myr to model long term paleointensity behavior a large ensemble of models is sampled from which a final representative mean model is extracted the resulting paleointensity model confirms published conclusions that the single silicate crystal method gives significantly different results from more conventional whole rock paleointensity methods this makes it difficult to jointly model the two data types in the same analysis when the much larger whole rock data set is considered a stable paleointensity of 5 46 0 28 10 22 a m 2 for the last 202 myr is consistent with the 95 confidence interval of the paleointensity model statistical tests indicate no significant correlation between reversal frequency and field intensity at the 0 05 level however this result is likely due to the characteristics of the pint database rather than being a genuine physically representative conclusion given the paucity of data and general state of the global paleointensity database concerted efforts to increase the number of high quality well dated paleointensity data are required before conclusions about a link between geomagnetic field intensity and reversal frequency can be confidently drawn

whole mantle p wave travel time tomography abstract a method of tomographic inversion to obtain three dimensional velocity perturbations in the earth s whole mantle has been developed and applied to more than two million p wave arrival time data reported by international seismology center isc the model is parameterized with 32 768 blocks the divisions in latitude longitude and radius are 32 64 and 16 respectively horizontal cell size is 5 6 5 6 the layer thicknesses vary with depth 29 km just below the surface and 334 km just above the core mantle boundary starting from a spherically symmetric earth model we obtained a three dimensional model using the following iterative procedures first we relocated all the events second we backprojected the residual into the whole mantle third we refined the spherically symmetric earth model the solutions have been converged in five iterations we adopted the following techniques in the backprojection procedure the first order smoothness was introduced as a damping which makes the solution independent of the starting model and its apparent fluctuation minimal the basic equations for delay times and smoothness are solved using the conjugate gradient method an iterative method which guarantees the convergence of solution into the exact least squares solution the weight on the smoothness i e the damping factor was objectively determined by a simplified cross validation technique the final solution was obtained as an average of the ten solutions each of which was derived from one tenth of the total data set the reliability of the solution is examined in two ways 1 mapping the resolution given by the reconstruction of checkerboard patterns and 2 mapping the variance given from the gaussian noise input this is the first result which delineates the whole mantle structure with its reliability mapping the longest wavelength anomalies of the lower mantle are similar to those of previous studies by dziewonski 1984 and hager and clayton 1989 however the shorter wavelength patterns have many discrepancies the fast anomalies of the uppermost mantle beneath the shield and the slow anomalies beneath the active tectonic regions are clearly seen we also revealed the l 2 pattern at the transition zone reported by the previous surface wave and free oscillation studies the most striking feature is that of the fast anomalies lying along the extension of the large subducting plate up to depths of about 1000 km or more the resolving powers in these regions are generally good

a bayesian partition modelling approach to resolve spatial variability in climate records from borehole temperature inversion summary collections of suitably chosen borehole profiles can be used to infer large scale trends in ground surface temperature gst histories for the past few hundred years these reconstructions are based on a large database of carefully selected borehole temperature measurements from around the globe since non climatic thermal influences are difficult to identify representative temperature histories are derived by averaging individual reconstructions to minimize the influence of these perturbing factors this may lead to three potentially important drawbacks the net signal of non climatic factors may not be zero meaning that the average does not reflect the best estimate of past climate the averaging over large areas restricts the useful amount of more local climate change information available and the inversion methods used to reconstruct the past temperatures at each site must be mathematically identical and are therefore not necessarily best suited to all data sets in this work we avoid these issues by using a bayesian partition model bpm which is computed using a trans dimensional form of a markov chain monte carlo algorithm this then allows the number and spatial distribution of different gst histories to be inferred from a given set of borehole data by partitioning the geographical area into discrete partitions profiles that are heavily influenced by non climatic factors will be partitioned separately conversely profiles with climatic information which is consistent with neighbouring profiles will then be inferred to lie in the same partition the geographical extent of these partitions then leads to information on the regional extent of the climatic signal in this study three case studies are described using synthetic and real data the first demonstrates that the bayesian partition model method is able to correctly partition a suite of synthetic profiles according to the inferred gst history in the second more realistic case a series of temperature profiles are calculated using surface air temperatures of a global climate model simulation in the final case 23 real boreholes from the united kingdom previously used for climatic reconstructions are examined and the results compared with a local instrumental temperature series and the previous estimate derived from the same borehole data the results indicate that the majority 17 of the 23 boreholes are unsuitable for climatic reconstruction purposes at least without including other thermal processes in the forward model

minimum magnitude of completeness in earthquake catalogs examples from alaska the western united states and japan we mapped the minimum magnitude of complete reporting m c for alaska the western united states and for the junec earthquake catalog of japan mc was estimated based on its departure from the linear frequency magnitude relation of the 250 closest earthquakes to grid nodes spaced 10 km apart in all catalogs studied mc was strongly heterogeneous in offshore areas the mc was typically one unit of magnitude higher than onshore on land also mc can vary by one order of magnitude over distance less than 50 km we recommend that seismicity studies that depend on complete sets of small earthquakes should be limited to areas with similar mc or the minimum magnitude for the analysis has to be raised to the highest com mon value of mc we believe that the data quality as reflected by the mc level should be used to define the spatial extent of seismicity studies where mc plays a role the method we use calculates the goodness of fit between a power law fit to the data and the observed frequency magnitude distribution as a function of a lower cutoff of the magnitude data mc is defined as the magnitude at which 90 of the data can be modeled by a power law fit mc in the 1990s is approximately 1 2 0 4 in most parts of california 1 8 0 4 in most of alaska aleutians and panhandle excluded and at a higher level in the junec catalog for japan various sources such as ex plosions and earthquake families beneath volcanoes can lead to distributions that cannot be fit well by power laws for the hokkaido region we demonstrate how neglecting the spatial variability of m c can lead to erroneous assumptions about deviations from self similarity of earthquake scaling

modifications to existing ground motion prediction equations in light of new data we compare our recent ground motion prediction equations gmpes for western north america wna boore and atkinson 2008 ba08 and eastern north america ena atkinson and boore 2006 ab06 atkinson 2008 a08 to newly available ground motion data based on these comparisons we suggest revisions to our gmpes for both wna and ena the revisions for wna affect only those events with m 5 75 while those for ena affect all magnitudes these are simple modi fications to the existing gmpes that bring them into significantly better agreement with data the wealth of new data clearly demonstrates that these modifications are warranted we therefore recommend the use of the updated equations for seismic hazard analyses and other applications more detailed studies are under way by many investigators including ourselves to develop a new generation of ground motion models in both wna and ena from scratch through a comprehensive reevaluation of source path site and modeling issues in time those more complete models will replace those proposed in this study however as the new models will be several years in development we recommend using the modified models proposed herein labeled ba08 for wna ab06 for ena and a08 for ena to replace a08 as interim updates to our existing models the proposed models are in demonstrable agreement with a rich database of ground motions for moderate magnitude earthquakes in both wna and ena and are constrained at larger magnitudes by the ba08 magnitude and distance scaling

earthquake ground motion prediction equations for eastern north america new earthquake ground motion relations for hard rock and soil sites in eastern north america ena including estimates of their aleatory uncertainty vari ability have been developed based on a stochastic finite fault model the model incorporates new information obtained from ena seismographic data gathered over the past 10 years including three component broadband data that provide new in formation on ena source and path effects our new prediction equations are similar to the previous ground motion prediction equations of atkinson and boore 1995 which were based on a stochastic point source model the main difference is that high frequency amplitudes f 5 hz are less than previously predicted by about a factor of 1 6 within 100 km because of a slightly lower average stress parameter 140 bars versus 180 bars and a steeper near source attenuation at frequencies less than 5 hz the predicted ground motions from the new equations are generally within 25 of those predicted by atkinson and boore 1995 the prediction equations agree well with available ena ground motion data as evidenced by near zero average residuals within a factor of 1 2 for all frequencies and the lack of any significant residual trends with distance however there is a tendency to positive residuals for moderate events at high frequencies in the distance range from 30 to 100 km by as much as a factor of 2 this indicates epistemic uncertainty in the prediction model the positive residuals for moderate events at 100 km could be eliminated by an increased stress parameter at the cost of producing negative residuals in other magnitude distance ranges adjustment factors to the equations are provided that may be used to model this effect

pliocene paleoclimatic reconstruction using dinoflagellate cysts comparison of methods the application of quantitative and semiquantitative methods to assemblage data from dinoflagellate cysts shows potential for interpreting past environments both in terms of paleotemperature estimates and in recognizing water masses and circulation patterns estimates of winter sea surface temperature wsst were produced by using the impagidinium index ii method and by applying a winter temperature transfer function tfw estimates of summer sea surface temperature ssst were produced by using a summer temperature transfer function tfs two methods based on a temperature distribution chart act and actpo and a method based on the ratio of gonyaulacoid protoperidinioid specimens g p wsst estimates from the ii and tfw methods are in close agreement except where impagidinium species are sparse ssst estimates from tfs are more variable the value of the g p ratio for the pliocene data in this paper is limited by the apparent sparsity of protoperidinioids which results in monotonous ssst estimates of 14 26 c the act methods show two biases for the pliocene data set taxonomic substitution may force matches yielding incorrect temperature estimates and the method is highly sensitive to the end points of species distributions dinocyst assemblage data were applied to reconstruct pliocene sea surface temperatures between 3 5 2 5 ma from dsdp hole 552a and odp holes 646b and 642b which are presently located beneath cold and cool temperate waters north of 56 n our initial results suggest that at 3 0 ma wssts were a few degrees c warmer than the present and that there was a somewhat reduced north south temperature gradient for all three sites it is likely that sssts were also warmer but by an unknown perhaps large amount past oceanic circulation in the north atlantic was probably different from the present

the key role of vertical land motions in coastal sea level variations a global synthesis of multisatellite altimetry tide gauge data and gps measurements abstract this study aims to quantify the vertical motions driving the decadal coastline mobility and their uncertainty at global scale multisatellite altimetry is combined with tide gauges and global positioning system gps observations to evaluate the marine and crustal components of relative sea level variations vertical land motions and sea level variations are estimated simultaneously over the past 20 years for a network of 886 ground stations with accuracies better than 1 7 mm yr the altigaps database present significant interest both by its technical characteristics global coverage larger number of sites longer period of observation improved accuracy and by the novelty of the applications empowered altigaps offers the opportunity to look independently into the recent dynamic processes affecting the ocean and the interior of the earth here the role of vertical land motions in relative sea level variations is explored to better understand the natural hazards associated with sea level rise in coastal areas global evidence for the local variability in vertical land motions is provided which may either amplify or attenuate the apparent rise of the sea at the coast a set of 182 potential vulnerable localities are identified by large coastal subsidence 1 5 mm yr which increases by several times the effects of climate induced sea level rise for coastal management purposes both marine absolute sea level variations and crustal vertical land motions components of vertical coastal motions relative sea level variations should therefore be accounted for

adaptive whole earth tomography 1 an approach for seismic tomography is presented which allows the parameterization to be refined during the inversion the objective is to use the data to refine the mesh and the velocity model together and hence both are considered part of the solution some simple rules are used to identify the volumes of a three dimensional model in need of refinement the self adaptive parameterization is applied to an initial mesh built from uniformly distributed spherical triangles and delaunay tetrahedra application of the technique to a typical summary ray p wave arrival time data set shows it to be both feasible and practical for large scale whole earth tomography a noticeable trend in the resulting models as the parameterization is refined is the thinning of the farallon and tethys subduction features imaged in the mid mantle together with an increase in amplitude of the velocity perturbation

a statistical assessment of seismic models of the u s continental crust using bayesian inversion of ambient noise surface wave dispersion data we present a new approach for evaluating existing crustal models using ambient noise datasets and its associated uncertainties we use a transdimensional hierarchical bayesian inversion thbi approach to invert ambient noise surface wave phase dispersion maps for love and rayleigh waves using measurements obtained from ekstrom 2014 spatiospectral analysis show that our results are comparable to a linear least squares inverse approach except at higher harmonic degrees but the procedure has additional advantages 1 it yields an auto adaptive parameterization that follows earth structure without making restricting assumptions on model resolution regularization or damping and data errors 2 it can recover non gaussian phase velocity probability distributions while quantifying and separating the sources of uncertainties in the data measurements and modeling procedure and 3 it enables statistical assessments of different crustal models e g crust1 0 litho1 0 and nacr14 using variable resolution residual and standard deviation maps estimated from the ensemble these assessments show that in the stable old crust of the archean the misfits are statistically negligible requiring no significant update to crustal models from the ambient noise dataset in other regions of the us significant updates to regionalization and crustal structure are expected especially in the shallow sedimentary basins and the tectonically active regions where the differences between model predictions and data are statistically significant

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

decoding the origins of vertical land motions observed today at coasts in recent decades geodetic techniques have allowed detecting vertical land motions and sea level changes of a few millimetres per year based on measurements taken at the coast tide gauges on board of satellite platforms satellite altimetry or both global navigation satellite system here contemporary vertical land motions are analysed from january 1993 to july 2013 at 849 globally distributed coastal sites the vertical displacement of the coastal platform due to surface mass changes is modelled using elastic and viscoelastic green s functions special attention is paid to the effects of glacial isostatic adjustment induced by past and present day ice melting various rheological and loading parameters are explored to provide a set of scenarios that could explain the coastal observations of vertical land motions globally in well instrumented regions predicted vertical land motions explain more than 80 per cent of the variance observed at scales larger than a few hundred kilometres residual vertical land motions show a strong local variability especially in the vicinity of plate boundaries due to the earthquake cycle significant residual signals are also observed at scales of a few hundred kilometres over nine well instrumented regions forming observation windows on unmodelled geophysical processes this study highlights the potential of our multitechnique database to detect geodynamical processes driven by anthropogenic influence surface mass changes surface loading and glacial isostatic adjustment and tectonic activity including the earthquake cycle sediment and volcanic loading as well as regional tectonic constraints future improvements should be aimed at densifying the instrumental network and at investigating more thoroughly the uncertainties associated with glacial isostatic adjustment models

tomographic imaging of the lowermost mantle with differential times of refracted and diffracted core phases pkp pdiff the mapping of variations in p wave speed in the deep mantle is restricted by the uneven sampling of p waves in particular beneath the southern hemisphere to enhance data coverage we augmented the 1 6 million summary rays of p pp and pwp that we used in previous studies with differential travel times of diffracted and refracted core phases for the core refracted differential travel time residuals pkpab pkpdf and pkpab pkpbc we used 1383 cross correlated digital waveforms as well as 27 000 routinely processed bulletin data we used the waveform data to define quality criteria for the selection and reduction of the bulletin pkp data for pkpdf pdiff we only considered 543 records derived from waveform cross correlation no pcp data were used in this study we used optical ray theory to calculate the ray paths associated with the p pp pwp and pkp data which are measured at 1 hz however to account for the large fresnel zones of the low frequency 50 mhz pkpdf pdiff data we estimated the three dimensional shape of the frechet sensitivity kernels from kernels calculated by normal mode summation the use of these kernels allows us to properly distribute the sensitivity for a given seismic phase over a large mantle volume while allowing the high frequency data to constrain small scale structure the differential times are relatively insensitive to source mislocation and to structure in the shallow mantle beneath source and receivers and they have previously been interpreted exclusively in terms of lateral structure directly above the core mantle boundary cmb however images thus obtained can be contaminated by effects of small scale structure elsewhere in the mantle here we do not make a priori assumptions about the mantle source of anomalous time differentials from test inversions we conclude that both upper and lower mantle structures that are poorly resolved by p data can be mapped into the core along pkp paths but that the effect of outer core structures if any on the mantle model is small compared to the inversion of the p pp and pwp alone the inclusion of the pkpab pkpdf and pkpab pkpbc and pkpdf pdiff data improves the resolution of structure beneath 2200 km depth in particular the joint inversion puts better constraints on the long wavelength variations in the very deep mantle and yields an increase in the amplitude of velocity perturbations near the cmb that is in agreement with but still smaller than inferences from shear wave studies resolution tests indicate that in some regions the enhanced definition of structure is significant but in most regions the improvements are subtle and structure remains poorly resolved in large regions of the mantle

imaging the subsurface using induced seismicity and ambient noise 3 d tomographic monte carlo joint inversion of earthquake body wave traveltimes and surface wave dispersion

across fault velocity gradients and slip behavior of the san andreas fault near parkfield a long lasting question in earthquake physics is why slip on faults occurs as creep or dynamic rupture we compute passive measurements of the seismic p wave velocity gradient across the san andreas fault near parkfield where this transition of slip mode occurs at a scale of a few kilometers unbiased measurements are obtained through the application of a new bayesian local earthquake tomographic code that avoids the imposition of any user defined initial velocity contrast across the fault or any damping scheme that may cause biased amplitude in retrieved seismic velocities we observe that across fault velocity gradients correlate with the slip behavior of the fault the p wave velocity contrast decays from 20 in the fault section that experience dynamic rupture to 4 in the creeping section suggesting that rapid change of material properties and attitude to sustain supra hydrostatic fluid pressure are conditions for development of dynamic rupture low vp and high vp vs suggest that fault rheology at shallow depth is conversely controlled by low frictional strength material

probabilistic seismic hazard estimation for peninsular india peninsular india 10 0 n 28 0 n 68 0 e 90 0 e is one of the oldest and seismically most stable landmasses of the indian plate recent seismic history however shows that more than five damaging earthquakes with magnitudes greater than mw 6 0 have occurred in this region highlighting the importance of seismic hazard assessment for the region this article estimates the probabilistic seismic hazard associated with peninsular india with a zoneless approach incorporating the observed seismic activity and known geological characteristics of the region the seismicity parameters for hazard assessment have been estimated incorporating com pleteness criteria for various spans of the catalog data the spatial and temporal variations of seismic activity have been modeled using different source models seis mic source zones for the region have been defined on the basis of large scale geo logical features which are used for assigning the maximum possible earthquake potential due to the poorly known attenuation characteristics of the study region three appropriate attenuation models have been used for the estimation of ground motion parameters hazard maps for peninsular india have been developed using a convolution scheme based on weighting and incorporating various uncertainties in volved while modeling different parameters the comparison of the probabilistic seismic hazard map developed herein with the hazard map specified in the indian standards shows that the design parameters in the indian standards may significantly underestimate the seismic hazard in some regions of peninsular india

tsunami source uncertainty estimation the 2011 japan tsunami this article was published in the journal of geophysical research solid earth 2016 american geophysical union and the definite version is available at http dx doi org 10 1002 2015jb012764 the journal s website is at http onlinelibrary wiley com doi 10 1002 2015jb012764 abstract jsessionid bf5813b61924fb094f31bc8f213840a1 f02t04

probabilistic surface reconstruction of coastal sea level rise during the twentieth century we present a new surface reconstruction procedure based on the bayesian inference method for coastal relative sea level variation during the twentieth century average rates are computed from tide gauge records models based on a voronoi tessellation adapt to the level of information which proves well suited to the strong heterogeneity of data each point of the reconstructed surface is defined through a probability density function a format particularly well adapted to this climate related datum the resolution of reconstructed surfaces strongly varies among the six large regions considered and within a given region anomalous sea level variations recorded locally are shown to reflect either anthropogenic effects or well identified fast tectonics for a poor data coverage these can cause a problematic distortion of the reconstructed surface europe north america australia and africa present a single trend with a decreasing precision of the reconstructed surface as a function of resolution of the tide gauge record the most prominent feature in europe is the pronounced uplift of fennoscandia coasts of united states have the best resolution in north america and present stronger rates of sea level rise on the atlantic than their european counterparts australia especially in the north and africa are poorly resolved asia and south america depart clearly from this trend a relatively uniform rise is obtained for asia in spite of a good tide gauge record conversely the reconstructed surface for south america presents an exceptional degree of roughness at odds with a relatively poor record overall this method not only offers a new assessment of sea level change validating earlier results but also quantifies the reliability of estimates

1 d 2 d and 3 d monte carlo ambient noise tomography using a dense passive seismic array installed on the north sea seabed