numerical shake prediction for earthquake early warning data assimilation real time shake mapping and simulation of wave propagation many of the present earthquake early warning eew systems quickly determine an event s hypocenter and magnitude and then predict strengths of ground motions the m w 9 0 tohoku earthquake however revealed some technical issues with such methods 1 underprediction at large distances due to the large extent of the fault rupture and 2 overprediction because the system was confused by multiple aftershocks that occurred simultaneously to address these issues we propose a new concept for eew in which the distribution of the present wavefield is estimated precisely in real time real time shake mapping by applying a data assimilation technique and then the future wavefield is predicted time evolutionally by simulation of seismic wave propagation information on the hypocenter location and magnitude is not necessarily required we call this method in which physical processes are simulated from the precisely estimated present condition numerical shake prediction because of its analogy to numerical weather prediction in meteorology by applying the proposed method to the 2011 tohoku earthquake and the 2004 mid niigata prefecture earthquake m w 6 7 we show that numerical shake prediction can precisely and rapidly predict ground motion in real time online material animations as examples of numerical shake prediction

contribution of small glaciers to global sea level observed long term changes in glacier volume and hydrometeorological mass balance models yield data on the transfer of water from glaciers excluding those in greenland and antarctica to the oceans the average observed volume change for the period 1900 to 1961 is scaled to a global average by use of the seasonal amplitude of the mass balance these data are used to calibrate the models to estimate the changing contribution of glaciers to sea level for the period 1884 to 1975 although the error band is large these glaciers appear to account for a third to half of observed rise in sea level approximately that fraction not explained by thermal expansion of the ocean

a model for a seismic computerized alert network in large earthquakes damaging ground motions may occur at large epicentral distances because of the relatively slow speed of seismic waves it is possible to construct a system to provide short term warning as much as several tens of seconds of imminent strong ground motions from major earthquakes automated safety responses could be triggered by users after receiving estimates of the arrival time and strength of shaking expected at an individual site although warning times are likely to be short for areas greatly damaged by relatively numerous earthquakes of moderate size large areas that experience very strong shaking during great earthquakes would receive longer warning times

earthquake monitoring in southern california for seventy seven years 1932 2008 the southern california seismic network scsn has produced the scsn earthquake catalog from 1932 to the present a period of more than 77 yrs this catalog consists of phase picks hypocenters and magnitudes we present the history of the scsn and the evolution of the catalog to facilitate user understanding of its limitations and strengths hypocenters and magnitudes have improved in quality with time as the number of stations has increased gradually from 7 to 400 and the data acquisition and measuring procedures have become more sophisticated the magnitude of completeness m c of the network has improved from m c 3 25 in the early years to m c 1 8 at present or better in the most densely instrumented areas mainshock aftershock and swarm sequences and scattered individual background earthquakes characterize the seismicity of more than 470 000 events the earthquake frequency size distribution has an average b value of 1 0 with m 6 0 events occurring approximately every 3 yrs the three largest earthquakes recorded were 1952 m w 7 5 kern county 1992 m w 7 3 landers and 1999 m w 7 1 hector mine sequences and the three most damaging earthquakes were the 1933 m w 6 4 long beach 1971 m w 6 7 san fernando and 1994 m w 6 7 northridge earthquakes all of these events ruptured slow slipping faults located away from the main plate boundary fault the san andreas fault their aftershock sequences constitute about a third of the events in the catalog the fast slipping southern san andreas fault is relatively quiet at the microseismic level and has not had an m 6 earthquake since 1932 in contrast the slower san jacinto fault has the highest level of seismicity including several m 6 events thus the spatial and temporal seismicity patterns exhibit a complex relationship with the plate tectonic crustal deformation

geology geochemistry and 40ar 39ar ages of the cerro millo epithermal high sulfidation gold prospect southern peru abstract the high sulfidation system of cerro millo is hosted in a late miocene andesitic paleo stratovolcano in the high andes of southern peru very pronounced advanced argillic alunite silicic and argillic kaolinite and smectite alteration characterizes the central part of the hydrothermal system propylitic alteration is developed in a 3 to 4 km wide outer halo abundant alunite occurs as hypogene acicular crystals and very fine grained aggregates the latter formed during near surface steam heated overprinting hypogene alunite has an ar ar plateau age of 10 8 0 9 ma 2 and is synchronous with the andesitic volcanism ar ar on biotite 11 0 0 5 ma a second ill defined alunite age plateau of 8 0 0 9 ma is probably related to steam heated overprint and points to major erosion in between both hydrothermal events telescoping is also evident by a series of silicified horizons which mark the paleo groundwater table these units have elevated mercury antimony and arsenic levels late phase barite occurs in some structurally controlled advanced argillic altered envelopes the hypogene alteration mineralogy points to temperatures at 250 c hydraulic fracturing and steam heated overprinting suggest a shallow boiling environment slight gold enrichment is observed in the lowermost exposed parts of the system

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

complexity of the mw 6 3 2009 l aquila central italy earthquake 2 broadband strong motion modeling 1 near fault strong ground motions 0 1 10 hz recorded during the mw 6 3 2009 l aquila earthquake exhibit great spatial variability modeling the observed seismograms allows linking distinct features of the observed wavefield to particular source and propagation effects and provides insights on strong motion complexity from this moderate magnitude event we utilize a hybrid integral composite approach based on a k square kinematic rupture model combining low frequency coherent and high frequency incoherent source radiation and providing omega squared source spectral decay several source model features proven to be stable by means of an uncertainty analysis in the preceding low frequency 2 hz

real time finite fault rupture detector finder for large earthquakes to provide rapid estimates of fault rupture extent during large earthquakes we have developed the finite fault rupture detector algorithm finder finder uses image recognition techniques to detect automatically surface projected fault ruptures in real time assuming a line source by estimating their current centroid position length l and strike the approach is based on a rapid high frequency near far source classification of ground motion amplitudes in a dense seismic network station spacing 50 km and comparison with a set of pre calculated templates using matching by correlation to increase computational efficiency we perform the correlation in the wavenumber domain finder keeps track of the current dimensions of a rupture in progress errors in l are typically on the same order as station spacing in the network the continuously updated estimates of source geometries as provided by finder make predicted shaking intensities more accurate and thus more useful for earthquake early warning shakemaps and related products the applicability of the algorithm is demonstrated for several recorded and simulated earthquakes with different focal mechanisms including the 2009 m w 6 3 l aquila italy the 1999 m w 7 6 chichi taiwan and the m w 7 8 shakeout scenario earthquake on the southern san andreas fault california

tree ring based reconstructions of north american glacier mass balance through the little ice age contemporary warming transition abstract glacier mass balance reconstructions provide a means of placing relatively short observational records into a longer term context in western north america mass balance records span four to five decades and capture a relatively narrow window of glacial behavior over an interval that was dominated by warming and ablation we use temperature and moisture sensitive tree ring series to reconstruct annual mass balance for six glaciers in the pacific northwest and alaska mass balance models rely on the climatic sensitivity of tree ring chronologies and teleconnection patterns in the north pacific the reconstructions extend through the mid to latter portions of the little ice age lia and explore the role of climate variability in forcing mass balance across multiple environmental gradients synchronous positive mass balance intervals coincide with regional moraine building and solar minima whereas differences in lia glacier behavior are related to synoptic climate forcing secular warming in the late 19th century to present corresponds with the only multi decadal intervals of negative mass balance in all glacier reconstructions this suggests that contemporary retreat in western north america is unique with respect to the last several centuries and that regional patterns of glacier variability are now dominated by global climate forcing

causes of glacier change in the source regions of the yangtze and yellow rivers on the tibetan plateau glaciers are an important element of the environment in the source regions of the yangtze and yellow rivers on the tibetan plateau using geographical information system techniques we have studied changes in the location of glacier margins in two areas the geladandong area in the headwaters of the yangtze and the a nyemaqen shan mountains in the headwaters of the yellow river marginal positions during the little ice age lia maximum in 1969 in the geladandong area in 1966 in the a nyemaqen shan and in 2000 in both areas were determined using aerial photographs satellite images topographical maps and digital elevation models extrapolating the results to the entire source regions of the yangtze and yellow rivers we estimate that the total glacierized area decreased about 1 7 between 1969 and 2000 in the geladandong area and about 17 between 1966 and 2000 in the a nyemaqen shan glaciers were stable or advanced slightly between 1969 and 1995 in the geladandong area and between 1966 and 1981 in the a nyemaqen shan but have retreated since the mid 1990s in the former and since the 1980s in the latter significant increases in summer air temperature and decreases in annual precipitation are the causes of the present retreat as a consequence of the retreat water storage as ice in the yangtze and yellow river drainages is decreasing by 65 70 106 m3 a 1

application of seismic array processing to earthquake early warning earthquake early warning eew systems that issue warnings prior to the arrival of strong shaking are essential in mitigating earthquake hazard currently operating eew systems work on point source assumptions and are of limited effectiveness for large events for which ignoring finite source effects result in magnitude underestimation here we explore the concept of characterizing rupture dimensions in real time for eew using small aperture seismic arrays located near active faults back tracing array waveforms allow estimation of the extent of the rupture front as a proxy of the rupture size and directivity in real time providing complementary eew capabilities for m 7 earthquakes to existing eew systems we implement it in a simulated real time environment and analyze the 2004 m 6 parkfield california earthquake recordings by the u s geological survey parkfield dense seismograph array upsar array and the 2010 m 7 2 el mayor cucapah earthquake recordings by strong motion sensors in san diego california we find it important to correct for the bias in back azimuth induced by dipping structures beneath the upsar array based on data from smaller events our estimated rupture length is 30 shorter than those inferred from other studies but still reasonable for eew purposes we attribute this difference to rupture directivity effects and the limited field of view of a single array the accuracy of the approach may be improved with a network of arrays with overlapping fields of view we demonstrate this by tracking the 2011 tohoku earthquake rupture with two clusters of hi net stations in kyushu and northern hokkaido the obtained results are consistent with teleseismic back projection results and yield reasonable estimates of rupture length and directivity compared with other proposed finite fault eew approaches the array method is less affected by the coarseness of a global positioning system or seismic network and provides a high frequency characterization of the rupture that yields more suitable predictors of ground shaking for certain structures

cybershake derived ground motion prediction models for the los angeles region with application to earthquake early warning real time applications such as earthquake early warning eew typically use empirical ground motion prediction equations gmpes along with event magnitude and source to site distances to estimate expected shaking levels in this simplified approach effects due to finite fault geometry directivity and site and basin response are often generalized which may lead to a significant under or overestimation of shaking from large earthquakes m 6 5 in some locations for enhanced site specific ground motion predictions considering 3 d wave propagation effects we develop support vector regression svr models from the scec cybershake low frequency 415 000 finite fault rupture scenarios 6 5 m 8 5 for southern california defined in ucerf 2 0 we use cybershake to demonstrate the application of synthetic waveform data to eew as a proof of concept being aware that these simulations are not yet fully validated and might not appropriately sample the range of rupture uncertainty our regression models predict the maximum and the temporal evolution of instrumental intensity mmi at 71 selected test sites using only the hypocentre magnitude and rupture ratio which characterizes uni and bilateral rupture propagation our regression approach is completely data driven where here the cybershake simulations are considered data and does not enforce pre defined functional forms or dependencies among input parameters the models were established from a subset 20 per cent of cybershake simulations but can explain mmi values of all 400 k rupture scenarios with a standard deviation of about 0 4 intensity units we apply our models to determine threshold magnitudes and warning times for various active faults in southern california that earthquakes need to exceed to cause at least moderate strong or very strong shaking in the los angeles la basin these thresholds are used to construct a simple and robust eew algorithm to declare a warning the algorithm only needs to locate the earthquake and to verify that the corresponding magnitude threshold is exceeded the models predict that a relatively moderate m6 5 7 earthquake along the palos verdes newport inglewood rose canyon elsinore or san jacinto faults with a rupture propagating towards la could cause very strong to severe shaking in the la basin however warning times for these events could exceed 30 s

glacier change in western north america influences on hydrology geomorphic hazards and water quality the glaciers of western canada and the conterminous united states have dominantly retreated since the end of the little ice age lia in the nineteenth century although average rates of retreat varied from strong in the first half of the twentieth century with glaciers stabilizing or even advancing until 1980 and then resuming consistent recession this retreat has been accompanied by statistically detectable declines in late summer streamflow from glacier fed catchments over much of the study area although there is some geographical variation over recent decades glaciers in northwest bc and southwest yukon have lost mass dominantly by thinning with relatively low rates of terminal retreat and glacier fed streams in that region have experienced increasing flows in many valleys glacier retreat has produced geomorphic hazards including outburst floods from moraine dammed lakes mass failures from oversteepened valley walls and debris flows generated on moraines in addition to these hydrologic and geomorphic changes evidence is presented that glacier retreat will result in higher stream temperatures possibly transient increases in suspended sediment fluxes and concentrations and changes in water chemistry with climate projected to continue warming over the twenty first century current trends in hydrology geomorphology and water quality should continue with a range of implications for water resources availability and management and hydroecology particularly for cool and cold water species such as salmonids copyright 2008 john wiley sons ltd

a site conditions map for california based on geology and shear wave velocity one simple way of accounting for site conditions in calculating seismic hazards is to use the shear wave velocity in the shallow subsurface to classify materials the average shear wave velocity to 30 m v 30s has been used to develop site categories that can be used for modifying a calculated ground motion to account for site conditions we have prepared a site category map of california by first classifying the geologic units shown on 1 250 000 scale geologic maps our classification of geologic units is based on v 30s measured in 556 profiles and geological similarities between units for which we have v s data and the vast majority of units for which we have no data we then digitized the geologic boundaries from those maps that separated units with different site classifications v s data for california shows that several widespread geologic units have ranges of v 30s values that cross the boundaries between nehrp ubc site categories the franciscan complex has v 30s values across ubc categories b and c with a mean value near the boundary between those two categories older alluvium and late tertiary bedrock have v 30s values that range from about 300 to about 450 m sec across the boundary between categories c and d to accommodate these units we have created intermediate categories which we informally call bc and cd geologic units that have or are interpreted to have v 30s values near the boundary of the ubc categories are placed in these intermediate units in testing our map against the available v 30s measurements we have found that 74 of the measured v 30s values fall within the range assigned to the v s category where they fall on the map this ratio is quite good considering the inherent problems in plotting site specific data on a regional map and the variability of physical properties in geologic units we have also calculated the mean and distribution of v 30s for each of our map units and prepared composite profiles showing the variation of v s in the upper 100 m from the available v s data these data show that the map categories that we have defined based on geologic units have different v s properties that can be taken into account in calculating seismic hazards

the new remote sensing derived swiss glacier inventory ii first results complete swiss glacier inventories are available for 1850 reconstructed and 1973 from aerial photography connected to the global land ice measurements from space project a new swiss glacier inventory for approximately the year 2000 sgi 2000 is compiled mainly based on satellite imagery the developed and applied remotesensing and geographical information system gis methods are described in part i of the contribution in part ii the inventory design first result analyses and comparisons with former glacial conditions are presented as basic entries sgi 2000 contains the individual glacier identification planimetric glacier boundaries as derived from image analysis digitized central flowlines and polygonal glacier basin maps all other parameters are automatically deduced from the above entries and a digital elevation model within a gis here we analyze a set of small bernese and valais glaciers of area 2 these glaciers lost about 21 of area from 1973 to 1998 in addition to about 80 during 1850 1973 both with respect to the 1973 area in order to track the latest trend in more detail anintermediate glacier condition has been compiled from satellite imagery of 1985 this analysis gave an increasing speed of area loss 19 for 1985 98

glacier change 1958 1998 in the north cascades national park complex washington usa the spatial characteristics for all glaciers in the north cascades national park complex usa were estimated in 1958 and again in 1998 the total glacier area in 1958 was 117 3 1 1 km 2 by 1998 the glacier area had decreased to 109 1 1 1 km 2 a reduction of 8 2 0 1 km 2 7 estimated volume loss during the 40 year period was 0 8 0 1 km 3 of ice this volume loss contributes up to 6 of the august september stream flow and equals 16 of the august september precipitation no significant correlations were found between magnitude of glacier shrinkage and topographic characteristics of elevation aspect or slope however the smaller glaciers lost proportionally more area than the larger glaciers and had a greater variability in fractional change than larger glaciers most of the well studied alpine glaciers are much larger than the population median so global estimates of glacier shrinkage based on these well studied glaciers probably underestimate the true magnitude of regional glacier change

the physical basis of glacier volume area scaling ice volumes are known for only a few of the roughly 160 000 glaciers worldwide but are important components of many climate and sea level studies which require water flux estimates a scaling analysis of the mass and momentum conservation equations shows that glacier volumes can be related by a power law to more easily observed glacier surface areas the relationship requires four closure choices for the scaling behavior of glacier widths slopes side drag and mass balance reasonable closures predict a volume area scaling exponent which is consistent with observations giving a physical and practical basis for estimating ice volumes glacier volume is insensitive to perturbations in the mass balance scaling but changes in average accumulation area ratios reflect significant changes in the scaling of both mass balance and ice volume

rapid disintegration of alpine glaciers observed with satellite data analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s by using digitized glacier outlines inferred from the 1973 inventory and landsat thematic mapper tm satellite data from 1985 to 1999 we obtained area changes of about 930 alpine glaciers the 18 area reduction as observed for the period 1985 to 1999 1 3 a corresponds to a seven times higher loss rate compared to the 1850 1973 decadal mean extrapolation of area change rates and cumulative mass balances to all alpine glaciers yields a corresponding volume loss of about 25 km since 1973 highly individual and non uniform changes in glacier geometry disintegration indicate a massive down wasting rather than a dynamic response to a changed climate our results imply stronger ongoing glacier retreat than assumed so far and a probable further enhancement of glacier disintegration by positive feedbacks

slip distribution and tectonic implication of the 1999 chi chi taiwan earthquake we report on the fault complexity of the large m w 7 6 chi chi earthquake obtained by inverting densely and well distributed static measurements consisting of 119 gps and 23 doubly integrated strong motion records we show that the slip of the chi chi earthquake was concentrated on the surface of a wedge shaped block the inferred geometric complexity explains the difference between the strike of the fault plane determined by long period seismic data and surface break observations when combined with other geophysical and geological observations the result provides a unique snapshot of tectonic deformation taking place in the form of very large 10m displacements of a massive wedge shaped crustal block which may relate to the changeover from over thrusting to subducting motion between the philippine sea and the eurasian plates

probabilistic prediction of rupture length slip and seismic ground motions for an ongoing rupture implications for early warning for large earthquakes earthquake earlywarning eew predicts future ground shaking based on presently available data long ruptures present the best opportunities for eew since many heavily shaken areas are distant from the earthquake epicentre and may receive long warning times predicting the shaking from large earthquakes however requires some estimate of the likelihood of the future evolution of an ongoing rupture an eew system that anticipates future rupture using the present magnitude or rupture length together with the gutenberg richter frequencysize statistics will likely never predict a large earthquake because of the rare occurrence of extreme events however it seems reasonable to assume that large slip amplitudes increase the probability for evolving into a large earthquake to investigate the relationship between the slip and the eventual size of an ongoing rupture we simulate suites of 1 d rupture series from stochastic models of spatially heterogeneous slip we find that while large slip amplitudes increase the probability for the continuation of a rupture and the possible evolution into a big one the recognition that rupture is occurring on a spatially smooth fault has an even stronger effect we conclude that aneewsystem for large earthquakes needs some mechanism for the rapid recognition of the causative fault e g from real time gps measurements and consideration of its smoothness an eew system for large earthquakes on smooth faults such as the san andreas fault could be implemented in two ways the system could issue a warning whenever slip on the fault exceeds a few metres because the probability for a large earthquake is high and strong shaking is expected to occur in large areas around the fault a more sophisticated eew system could use the present slip on the fault to estimate the future slip evolution and final rupture dimensions and using this information could provide probabilistic predictions of seismic ground motions along the evolving rupture the decision on whether an eew system should be realized in the first or in the second way or in a combination of both is user specific

a global approach to provide magnitude estimates for earthquake early warning alerts 1 we examine five different methods to estimate an earthquake s magnitude using only p wave data for use in earthquake early warning systems we test two input parameters the maximum predominant period of the p wave pmax and the displacement amplitude of the p wave s vertical component pd we apply our algorithms to 174 earthquakes 3 0 m 8 0 from california and japan that have also been used in previous calibration studies we also apply them to 1992 0 2 m 5 7 earthquakes that were processed by the real time earthquake alarm systems in california we find that pmax does not scale with magnitude for small earthquakes m 3 and is less accurate for large magnitude earthquakes than using pd alone we derive a global scaling relation between pd and magnitude and conclude that this global relationship provides the most accurate and robust magnitude estimate this relationship could be applied in earthquake source zones around the world

the new remote sensing derived swiss glacier inventory i methods a new swiss glacier inventory is to be compiled from satellite data for the year 2000 the study presented here describes two major tasks 1 an accuracy assessment of different methods for glacier classification with landsat thematic mapper tm data and a digital elevation model dem 2 the geographical information system gis based methods for automatic extraction of individual glaciers from classified satellite data and the computation of three dimensional glacier parameters such as minimum maximum and median elevation or slope and orientation by fusion with a dem first results obtained by these methods are presented in part ii of this paper kaab and others 2002 thresholding of a ratio image from tm4 and tm5 reveals the best suited glacier map the computation of glacier parameters in a gis environment is efficient and suitable for worldwide application the methods developed contribute to the u s geological survey led global land ice measurements from space glims project which is currently compiling a global inventory of land ice masses within the framework of global glacier monitoring haeberli and others 2000

complexity of the mw 6 3 2009 l aquila central italy earthquake 1 multiple finite extent source inversion 1 strong ground motion recordings of the mw 6 3 2009 l aquila earthquake are analyzed by a newly proposed slip inversion technique the source model consists of multiple finite extent mufex subsources the slip amplitude rupture velocity rake and risetime are assumed constant within each subsource the size and location of the mufex subsources have to be inferred independently from other methods preferably those free of strong constraints such as constant rupture velocity over the whole fault etc here we use two published approaches satisfying such requirement the truncated singular value decomposition and the iterative multiple point source deconvolution each mufex subsource is characterized by an individual set of trial nucleation points rupture velocities and nucleation times which are grid searched for each combination of these parameters the subsources slip is determined by the least squares approach this procedure thus provides not only the best fitting model but also a whole range of acceptable models allowing for the uncertainty analysis the method is demonstrated on three synthetic tests when applied to the l aquila data both the best fitting model and the uncertainty analysis suggest that the event consisted of two major episodes one with the rupture propagating immediately after the nucleation in the updip direction the other being delayed by 3 4 s with dominant propagation toward the se along the deeper part of the fault the retrieved complexity of the rupture propagation warns against attempts to stabilize inversions by the use of a constant rupture velocity over the whole fault

fault extent estimation for near real time ground shaking map computation purposes rapid evaluation of strong ground shaking maps after moderate to large earthquakes is crucial to recognizing those areas where the largest damage and losses are expected these maps play a fundamental role for emergency management this is particularly important for areas having high seismic risk potential and covered by dense seismic networks in near real time applications ground shaking maps are produced by integrating recorded data and estimates obtained by using ground motion predictive equations which assume point source models however particularly for large earthquakes improvements in the predictions of the peak ground motion can be obtained when fault extension and orientation are available in fact detailed source information allows one to use a more robust source to site distance metric compared with hypocentral distance in this paper a technique for estimating both fault extent in terms of its surface projection and dominant rupture direction is presented this technique can be used in near real time ground motion map calculation codes with the aim of improving ground motion estimates with respect to a point source model the model parameters are estimated by maximizing a probability density function based on the residuals between observed and predicted peak ground motion quantities the latter obtained by using predictive equations the model space to be investigated is defined through a bayesian approach and it is explored by a grid searching technique the effectiveness of the proposed technique is demonstrated by offline numerical tests using data from three earthquakes occurring in different seismotectonic environments the selected earthquakes are the 17 august 1999 m w 7 5 kocaeli turkey earthquake the 6 april 2009 m w 6 3 l aquila italy earthquake and the 17 january 1994 m w 6 7 northridge california earthquake the obtained results show that the proposed technique allows for fast and first order estimates of the fault extent and dominant rupture direction which could be used to improve ground shaking map calculations

rapid estimation of earthquake source and ground motion parameters for earthquake early warning using data from a single three component broadband or strong motion sensor we propose a new algorithm to rapidly determine earthquake source and ground motion parameters for earthquake early warning eew this algorithm uses the acceleration velocity and displacement waveforms of a single three component broadband bb or strong motion sm sensor to perform real time earthquake noise discrimination and near far source classification when an earthquake is detected the algorithm estimates the moment magnitude m epicentral distance and peak ground velocity pgv at the site of observation the algorithm was constructed by using an artificial neural network ann approach our training and test datasets consist of 2431 three component sm and bb records of 161 crustal earthquakes in california japan and taiwan with 3 1 m 7 6 at 115 km first estimates become available at t 0 0 25 s after the p pick and are regularly updated we find that displacement and velocity waveforms are most relevant for the estimation of m and pgv while acceleration is important for earthquake noise discrimination including site corrections reduces the errors up to 10 the estimates improve by an additional 10 if we use both the vertical and horizontal components of recorded ground motions the uncertainties of the predicted parameters decrease with increasing time window length t 0 larger magnitude events show a slower decay of these uncertainties than small earthquakes we compare our approach with the c algorithm and find that our prediction errors are around 60 smaller however in general there is a limitation to the prediction accuracy an eew system can provide if based on single sensor observations

location of largest earthquake slip and fast rupture controlled by along strike change in fault structural maturity due to fault growth earthquake slip distributions are asymmetric along strike but the reasons for the asymmetry are unknown we address this question by establishing empirical relations between earthquake slip profiles and fault properties we analyze the slip distributions of 27 large continental earthquakes in the context of available information on their causative faults in particular on the directions of their long term lengthening we find that the largest slips during each earthquake systematically occurred on that half of the ruptured fault sections most distant from the long term fault propagating tips i e on the most mature half of the broken fault sections meanwhile slip decreased linearly over most of the rupture length in the direction of long term fault propagation i e of decreasing structural maturity along strike we suggest that this earthquake slip asymmetry is governed by along strike changes in fault properties including fault zone compliance and fault strength induced by the evolution of off fault damage fault segmentation and fault planarity with increasing structural maturity we also find higher rupture speeds in more mature rupture sections consistent with predicted effects of low velocity damage zones on rupture dynamics since the direction s of long term fault propagation can be determined from geological evidence it might be possible to anticipate in which direction earthquake slip once nucleated may increase accelerate and possibly lead to a large earthquake our results could thus contribute to earthquake hazard assessment and earthquake early warning

finder v 2 improved real time ground motion predictions for m2 m9 with seismic finite source characterization recent studies suggest that small and large earthquakes nucleate similarly and that they often have indistinguishable seismic waveform onsets the characterization of earthquakes in real time such as for earthquake early warning therefore requires a flexible modeling approach that allows a small earthquake to become large as fault rupture evolves over time here we present a modeling approach that generates a set of output parameters and uncertainty estimates that are consistent with both small moderate m6 5 and large earthquakes m6 5 as is required for a robust parameter interpretation and shaking forecast our approach treats earthquakes over the entire range of magnitudes m2 as finite line source ruptures with the dimensions of small earthquakes being very small 100 m and those of large earthquakes exceeding several tens to hundreds of kilometres in length the extent of the assumed line source is estimated from the level and distribution of high frequency peak acceleration amplitudes observed in a local seismic network high frequency motions are well suited for this approach because they are mainly controlled by the distance to the rupturing fault observed ground motion patterns are compared with theoretical templates modeled from empirical ground motion prediction equations to determine the best line source and uncertainties our algorithm extends earlier work by bose et al for large finite fault ruptures this paper gives a detailed summary of the new algorithm and its offline performance for the 2016 m7 0 kumamoto japan and 2014 m6 0 south napa california earthquakes as well as its performance for about 100 real time detected local earthquakes 2 2 m 5 1 in california for most events both the rupture length and the strike are well constrained within a few seconds 10 s of the event origin in large earthquakes this could allow for providing warnings of up to several tens of seconds the algorithm could also be useful for resolving fault plane ambiguities of focal mechanisms and identification of rupturing faults for earthquakes as small as m2 5