ground motion modeling of the 1906 san francisco earthquake part ii ground motion estimates for the 1906 earthquake and scenario events abstract we estimate the ground motions produced by the 1906 san francisco earthquake making use of the recently developed song et al 2008 source model that combines the available geodetic and seismic observations and recently constructed 3d geologic and seismic velocity models our estimates of the ground motions for the 1906 earthquake are consistent across five ground motion modeling groups employing different wave propagation codes and simulation domains the simulations successfully reproduce the main features of the boatwright and bundock 2005 shakemap but tend to over predict the intensity of shaking by 0 1 0 5 modified mercalli intensity mmi units velocity waveforms at sites throughout the san francisco bay area exhibit characteristics consistent with rupture directivity local geologic conditions e g sedimentary basins and the large size of the event e g durations of strong shaking lasting tens of seconds we also compute ground motions for seven hypothetical scenarios rupturing the same extent of the northern san andreas fault considering three additional hypocenters and an additional random distribution of slip rupture directivity exerts the strongest influence on the variations in shaking although sedimentary basins do consistently contribute to the response in some locations such as santa rosa livermore and san jose these scenarios suggest that future large earthquakes on the northern san andreas fault may subject the current san francisco bay urban area to stronger shaking than a repeat of the 1906 earthquake ruptures propagating southward towards san francisco appear to expose more of the urban area to a given intensity level than do ruptures propagating northward

heat flow strong near fault seismic waves and near fault tectonics on the central san andreas fault the main san andreas fault strikes subparallel to compressional folds and thrust faults its fault normal traction is on average a factor of 1 2 thr 1 thr2 thr where thr is the coefficient of friction for thrust faults times the effective lithostatic pressure a useful upper limit for thr of 0 6 where is 3 12 is obtained from the lack of heat flow anomalies by considering off fault convergence at a rate of 1 mm yr for 10 km across strike if the fault normal traction is in fact this high the well known heat flow constraint of average stresses of 10 20 mpa during strike slip on the main fault becomes more severe only a few percent of the total slip during earthquakes can occur at the peak stress before dynamic mechanisms weaken the fault the spatial dimension of the high stress rupture tip zone is 10 m for 3 12 and for comparison 100 m for 1 high dynamic stresses during shaking occur within these distances of the fault plane in terms of scalars fine scale tectonic stresses cannot exceed the difference between failure stress and dynamic stress plate scale slip causes stresses to build up near geometrical irregularities of the fault plane strong dynamic stresses near the rupture tip facilitate anelastic deformation with the net effects of relaxing the local deviatoric tectonic stress and accommodating deformation around the irregularities there also is a mild tendency for near fault material to extrude upward slip on minor thrust faults causes the normal traction on the main fault to be spatially variable

the state of stress on some faults of the san andreas system as inferred from near field strong motion data we present a simple method to calculate the stress produced on an earthquake fault during rupture this method allows the complete evaluation of the stress spatio temporal history over the fault we apply this approach to study the changes in shear stress produced during four of the largest earthquakes which occurred along the san andreas fault system over the last 20 years the imperial valley earthquake of 1979 the morgan hill earthquake of 1984 the loma prieta earthquake of 1989 and the northridge earthquake of 1994 we use for this study the tomographic models of the fault rupture obtained from the inversion of the near field seismic data recorded during these earthquakes the results obtained show that the static and the dynamic stress drops vary greatly over the fault the peak values obtained for the four earthquakes studied range from about 20 to 100 mpa these high values imply that the initial shear stress level on the fault at the onset of the earthquake was high on at least a significant portion of the fault the regions of the fault which break with a high stress drop are also the regions where slip is large this suggests that most of the slip produced in a large earthquake takes place over the strong areas of the fault low slip regions tend to break with low stress drops after the earthquake the shear stress is increased over a significant portion of the fault which corresponds to low slip regions aftershock activity tends to be concentrated in these areas of stress increase the apparent strength of the fault before the earthquake that is the local shear stress increase which is required for rupture is also extremely heterogeneous the rupture velocity seems to be inversely correlated with this apparent fault strength the rupture accelerating over the weak areas of the fault and slowing down over the high strength areas

a supershear transition mechanism for cracks seismic data indicate that fault ruptures follow complicated paths with variable velocity because of inhomogeneities in initial stress or fracture energy we report a phenomenon unique to three dimensional cracks locally stronger fault sections rather than slowing ruptures drive them forward at velocities exceeding the shear wave speed this supershear mechanism differentiates barrier and asperity models of fault heterogeneity which previously have been regarded as indistinguishable high strength barriers concentrate energy producing potentially destructive pulses of strong ground motion

distance and azimuthal dependence of ground motion variability for unilateral strike slip ruptures abstract we investigate near field ground motion variability by computing the seismic wavefield for five kinematic unilateral rupture models of the 1992 m w 7 3 landers earthquake eight simplified unilateral rupture models based on the landers event and a large m w 7 8 shakeout scenario we include the geometrical fault complexity and consider different 1d velocity density profiles for the landers simulations and a 3d heterogeneous earth structure for the shakeout scenario for the landers earthquake the computed waveforms are validated using strong motion recordings we analyze the simulated ground motion data set in terms of distance and azimuth dependence of peak ground velocity pgv our simulations reveal that intraevent ground motion variability is higher in close distances to the fault ln pgv is well described by a cauchy lorentz function that provides a novel empirical quantification to model the spatial dependency of ground motion online material figures of slip distributions residuals to ground motion prediction equations gmpes distance and azimuthal dependence and directivity predictor of ground motion variability for different source models

hypocenter locations in finite source rupture models we use a database of more than 80 finite source rupture models for more than 50 earthquakes m w 4 1 8 1 with different faulting styles occurring in both tectonic and subduction environments to analyze the location of the hypocenter within the fault and to consider the correlation between hypocenter location and regions of large slip rupture in strike slip and crustal dip slip earthquakes tends to nucleate in the deeper sections of the fault subduction earthquakes do not show this tendency ratios of the hypocentral slip to either the average or the maximum slip show that rupture can nucleate at locations with any level of relative displacement rupture nucleates in regions of very large slip d 2 3 d max in only 16 of the events in regions of large slip 1 3 d max d d max in 35 of the events and in regions of low slip d 1 3 d max in 48 of the events these percentages significantly exceed the percentages of fault area with very large 7 and large 28 slip ruptures that nucleate in regions of low slip however tend to nucleate close to regions of large slip and encounter a zone of very large slip within half the total rupture length applying several statistical tests we conclude that hypocenters are not randomly located on a fault but are located either within or close to regions of large slip

analysis of a complex toppling circular slope failure abstract this technical note describes a complex failure that occurred in an open pit mine in valencia spain the failure which was analysed and interpreted in accordance with the local geology occurred in a slope comprised of a limestone rock mass in the upper part and a claystone sandstone sedimentary formation in the lower part the failure mechanism which was interpreted as complex toppling combining toppling and circular failure was back analysed using analytical and numerical techniques

fuzzy models for analysis of rock mass displacements due to underground mining in mountainous areas the displacement and deformations of rock mass due to underground mining has often resulted in major disasters throughout the world frequently inflicting heavy losses of life and damage to property and these disasters have motivated the development of rock mass mechanics the prediction of displacement of rock mass and their surface effects is an important problem of the rock mass mechanics in the excavation activities especially the coal and metal mining in mountainous areas based on results of the statistical analysis of a large amount of measured data in mining engineering the fundamental fuzzy model of displacements and deformations of rock mass is established by using the theory of fuzzy probability measures the theories of both two and three dimensional problems are developed and applied to the analysis of engineering problems in excavation and underground mining in mountainous areas the agreement of the theoretical results with the field measurements shows that our model is satisfactory and the formulae obtained are valid and thus can be effectively used for predicting the displacements and deformations and the safety evaluation of the buildings on the ground

multi synchrotron techniques to constrain mobility and speciation of zn associated with historical mine tailings abstract zinc speciation chemical forms and phytoavailability were determined within mine tailings and soil samples from a historical mining site in the xichu district central mexico for this purpose species determination and phase mapping were conducted using xas xrf and xrd and chemical extraction was performed to assess chemical forms and phytoavailability high concentrations of zn were recorded in the mine tailings 4681 mg kg 1 and relatively high concentrations were observed in the soils 319 mg kg 1 soil samples either exceeded the threshold value for exploratory assessment or yielded concentrations that may cause ecological risk igeo values indicate that the mine tailings were extremely polluted and soils were unpolluted to moderately polluted phytoavailable zn positively correlated with total zn content in the mine tailings 34 1719 mg kg 1 and soils 36 69 5 mg kg 1 and exceeded the threshold value for the development of ecotoxicological effects the average percentages of most mobile fractions water soluble exchangeable and carbonate bound in surficial and composite mine tailings were 31 and 34 respectively whereas that in the surrounding soils was 36 according to xas and linear combination fitting the main phases of zn in mine tailings were residual species whereas in soils the main phase was zinc carbonate hydrozincite minor components of zn were found as sulfate and sorbed onto goethite which was confirmed by xrd phase mapping synchrotron techniques suggest that zn sulfate and zn sorbed onto goethite are the main species controlling the mobility and availability of zn the potential high mobilization and dispersion of zn represent potential harm to surrounding ecosystems in the historical mine tailings of central mexico

variability of kinematic source parameters and its implication on the choice of the design scenario abstract near fault seismic recordings for recent earthquakes chi chi earthquake 1999 and parkfield earthquake 2004 show the high spatial heterogeneity of ground motion this variability is controlled by fault geometry rupture complexity and also by wave propagation and site effects nowadays the number of available records in the near source region is still not enough to infer a robust parameterization of the ground motion and to retrieve multiparametric predictive equations valid at close distances from the fault the use of a synthetic approach may help to overcome this limitation and to study the strong ground motion variability in this article we focus on ground motion dependence on different earthquakes breaking the same fault as it has been rarely recorded by instruments we model seismic scenarios from different rupture models of a fault similar to the 1980 irpinia italy earthquake source m w 6 9 a discrete wavenumber finite element technique is used to compute full wave displacement and velocity time series in the low frequency band up to 2 hz we investigate the variability of the ground motion as a function of different source parameters rupture velocity slip distribution nucleation point and source time function whose values depend on the state of knowledge of the physical model driving the process the probability density functions of the simulated ground motion parameters such as displacement response spectrum and peak ground velocity are used to identify particular scenarios that match specific engineering requests

structurally controlled instability damage and slope failure in a porphyry rock mass abstract rock slopes fail through structurally controlled mechanisms global circular failures or complex mechanisms depending on structural patterns and rock mass damage here structural geology rock mass characterisation terrestrial laser scanning tls ground based radar interferometry gb insar and finite element modelling are integrated to explore relationships between structure damage and global slope failure at mt gorsa trentino italy there a porphyry quarry has been excavated in complex strongly anisotropic rhyolitic ignimbrite rock masses the slope was affected by a major rockslide in 2003 and undergoes continuing instability site investigations and gb insar monitoring revealed that the 2003 failure was a roto translational rockslide involving about 400 000 m3 of disrupted rock structural analysis of tls and field data shows that the slope is affected by widespread structurally controlled mechanisms sliding toppling strain localization in kink bands the non obvious relationships between structurally controlled and global roto translational slope failure mechanisms are investigated by characterising rock mass damage in different slope sectors a new approach to quantify rock mass damage by mapping the geological strength index and interpreting its topographic signatures in tls point clouds is presented a persistent geological marker is systematically mapped in tls point clouds and correlations between attitude variability statistics and rock mass damage are established providing an efficient assessment tool rock mass damage increases in kinematic domains affected by structurally controlled instability gsi 35 40 and is maximum in areas of ongoing global instability gsi 15 20 the 2003 rockslide occurred inside a damaged rock mass zone with gsi

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

ground motion amplification in the santa monica area effects of shallow basin edge structure abstract the 1994 northridge earthquake produced ground motions in the northwest portion of the los angeles basin that were significantly larger than rock site motions observed at locations just north of the basin the santa monica area was hit particularly hard with numerous structures being damaged or destroyed by the strong ground shaking in this region the basin edge geology is controlled by the active strand of the east west striking santa monica fault and virtually all of the structural damage occurred at or south of the fault location we have used 2d finite difference ground motion simulations to investigate the effect of the basin edge structure in amplifying ground response constraints on the basin edge structure come from geologic cross sections geophysical data and seismological observations our simulations indicate that the shallow basin edge structure 1 km deep formed by the active strand of the santa monica fault creates a large amplification in motions immediately south of the fault scarp in very good agreement with mainshock damage patterns recorded ground motions and locations of elevated site response this large amplification results from constructive interference of direct waves with the basin edge generated surface waves and is quite similar to the basin edge effect associated with the 1995 kobe earthquake in addition we find that focusing effects created by the deeper basin structure 3 to 4 km deep cannot explain the large motions observed immediately south of the fault scarp this strongly suggests that the deep basin focusing models proposed by gao et al 1996 and alex and olsen 1998 are not likely explanations of the observed pattern of ground motion amplification in the santa monica area

broadband simulations for mw 7 8 southern san andreas earthquakes ground motion sensitivity to rupture speed using the high performance computing resources of the southern california earthquake center we simulate broadband 0 10 hz ground motions for three m w 7 8 rupture scenarios of the southern san andreas fault the scenarios incorporate a kinematic rupture description with the average rupture speed along the large slip portions of the fault set at 0 96 0 89 and 0 84 times the local shear wave velocity consistent with previous simulations a southern hypocenter efficiently channels energy into the los angeles region along the string of basins south of the san gabriel mountains however we find the basin ground motion levels are quite sensitive to the prescribed rupture speed with peak ground velocities at some sites varying by over a factor of two for variations in average rupture speed of about 15 these results have important implications for estimating seismic hazards in southern california and emphasize the need for improved understanding of earthquake rupture processes

source parameters of the 1908 messina straits italy earthquake from geodetic and seismic data 1 we carry out a nonlinear joint inversion of p wave first motion polarities and coseismic surface displacement data of the 1908 messina earthquake we model the earthquake using a single planar fault slip is at first assumed to be uniform across the whole fault then independent in a small set of coplanar subfaults and finally smoothly variable across the fault the first two steps are accomplished using a global minimization technique the main features of the retrieved model are very robust and independent of the seismic velocity profile of the presence of questionable bench marks and of the assumed residual distribution the along strike component of slip is about half the along dip component in agreement with the direction of the extensional stress axis retrieved from geological observations surface vertical displacement is consistent with tsunami data and with the morphology of the messina straits

the december 28 1908 messina straits southern italy earthquake waveform modeling of regional seismograms the 1908 messina straits earthquake is one of the most catastrophic events in history there were 60 000 to more than 100 000 deaths and the cities of messina and reggio calabria on the opposite sides of the straits were almost completely destroyed during the last decades only low magnitude events occurred in the area the 1908 earthquake is then crucial for understanding the mode of stress release in the area we collected and digitized several regional seismograms of this event recorded in central europe with the aim of studying the source characteristics in order to separate the path effects we analyzed recent events with simple and known sources owing to the small azimuth range spanned by the available stations we could not determine a fault plane solution for the messina straits event nor discriminate between the published focal mechanisms however the normal fault character of the rupture is confirmed by inverting the historical p waveforms we derived source time functions and obtained a seismic moment of 5 38 2 16 1019 n m mw 7 1 this is in good agreement with the results obtained by several authors from the inversion of the historical leveling data this value is confirmed by the sh wave modeling which also allowed the assessment of the unilateral northward character of the rupture propagation along an 43 km fault finally we applied a simple rupture model in order to derive the slip distribution along the fault the resulting function is in good correspondence with the geodetic inversions performed by boschi et al 1989 and de natale and pingue 1991 in particular a maximum slip of 4 m is located in proximity of the center of the slipped area the high dislocation patch beneath the messina harbor as depicted by de natale and pingue is not confirmed by our analysis and is probably connected to surface collapse of some of the bench marks

a study of surface subsidence and coal pillar safety for strip mining in a deep mine some villages and bridges are located on the ground surface of the working district no 7 in the wanglou coal mine if longwall mining is adopted the maximum deformation of the ground surface will exceed the safety value strip mining is employed for the working district no 7 which is widely used to reduce surface subsidence and the consequent damage of buildings on the ground surface to ensure the safety of coal pillars and improve the recovery coefficient theoretical analysis and numerical simulation flac 3d were adopted to determine the coal pillar and mining widths and to discuss the coal pillar stress distribution and surface subsidence for different mining scenarios the results revealed that the width of coal pillars should be larger than 162 m and the optimized mining width varies from 150 to 260 m as the coal seam is exploited vertical stress is mainly applied on the coal pillar inducing stress changes on its ribs the coefficient of mining induced stress varies from 2 02 to 2 62 for different mining scenarios the maximum surface subsidence and horizontal movement increase as the mining width increases however when the mining width increases to a certain value increasing the pillar width cannot significantly decrease the maximum subsidence to ensure the surface subsidence less than 500 mm the mining width should not be larger than 200 m considering the recovery coefficient and safety of the coal pillar a pillar width of 165 m is suggested

a spatial random field model to characterize complexity in earthquake slip 1 finite fault source inversions reveal the spatial complexity of earthquake slip over the fault plane we develop a stochastic characterization of earthquake slip complexity based on published finite source rupture models in which we model the distribution of slip as a spatial random field the model most consistent with the data follows a von karman autocorrelation function acf for which the correlation lengths a increase with source dimension for earthquakes with large fault aspect ratios we observe substantial differences of the correlation length in the along strike a x and downdip a z directions increasing correlation length with increasing magnitude can be understood using concepts of dynamic rupture propagation the power spectrum of the slip distribution can also be well described with a power law decay i e a fractal distribution in which the fractal dimension d remains scale invariant with a median value d 2 29 0 23 while the comer wave number k c which is inversely proportional to source size decreases with earthquake magnitude accounting for larger slip patches for large magnitude events our stochastic slip model can be used to generate realizations of scenario earthquakes for near source ground motion simulations

spatial relation between the 1908 messina straits earthquake slip and recent earthquake distribution 1 we re analyze coseismic surface displacement data of the 1908 messina earthquake taking into account both correlated and uncorrelated uncertainties to re determine the slip distribution on the fault plane using a data set of earthquakes occurred at crustal depth in the messina straits between july 1988 and december 2004 we evidence a peculiar recent seismicity distribution inside the fault volume of the 1908 messina straits earthquake with respect to other regions in the area an unusually large number of earthquakes is found in regions smoothly ringing slipped areas our results seem consistent with static coulomb stress variations inside the fault volume and regional strain rate from gps data but could also suggest that in the last 15 20 years the 1908 earthquake source has been releasing strain accumulated in portions of it which did not rupture during the 1908 event

estimation of an optimum velocity model in the calabro peloritan mountains assessment of the variance of model parameters and variability of earthquake locations summary accurate earthquake locations are of primary importance when studying the seismicity of a given area they allow important inferences on the ongoing seismo tectonics both for standard as well as for earthquake relative location techniques the velocity parameters are kept fixed to a priori values that are assumed to be correct and the observed traveltime residuals are minimized by adjusting the hypocentral parameters however the use of an unsuitable velocity model can introduce systematic errors in the hypocentre location precise hypocentre locations and error estimate therefore require the simultaneous solution of both velocity and hypocentral parameters we perform a simultaneous inversion of both the velocity structure and the hypocentre location in ne sicily and sw calabria italy since the density of the network is not sufficient for the identification of the 3 d structure with a resolution of interest here we restrict ourselves to a 1 d inversion using the well known code velest a main goal of the paper is the analysis of the stability of the inverted model parameters for this purpose we carry out a series of tests concerning the initial guesses of the velocity structure and locations used in the inversion we further assess the uncertainties which originate from the finiteness of the available data set carrying out resampling experiments from these tests we conclude that the data catalogue is sufficient to constrain the inversion we note that the uncertainties of the inverted velocities increases with depth on the other hand the inverted velocity structure depends decisively on the initial guess as they tend to maintain the overall shape of the starting model in order to obtain an improved starting model we derive a guess for the probable depth of the moho for this purpose we exploit considerations of the depth distribution of earthquake foci and of the shear strength of rock depending on its rheological behaviour at depth in a second step we derive a smooth starting model and repeated the inversion strong discontinuities tend to attract hypocentre locations which may introduce biases to the earthquake location using the smooth starting model we obtaine again a rather smooth model as final solution which gives the best traveltime residuals among all models discussed in this paper this poses severe questions as to the significance of velocity discontinuities inferred from rather vague a priori information besides this the use of those smooth models widely avoids the problems of hypocentre locations being affected by sudden velocity jumps an effect which can be extremely disturbing in relative location procedures the differences of the velocity structure obtained with different starting models is larger than those encountered during the bootstrap test this underscores the importance of the choice of the initial guess fortunately the effects of the uncertainties discussed here on the final locations turned out as limited that is less than 1 km for the horizontal coordinates and less than 2 km for the depth

near fault strong motion complexity of the 2000 tottori earthquake japan from a broadband source asperity model abstract the october 6 2000 tottori earthquake that occurred in central japan was an intermediate size strike slip event that produced a very large number of near field strong motion recordings the large amount of recorded data provides a unique opportunity for investigating a source asperity model of the tottori earthquake that combined with a hybrid strong motion simulation technique is able to reproduce the observed broadband frequency near fault ground motion we investigated the optimum source asperity parameters of the tottori earthquake by applying a genetic algorithm ga inversion scheme to optimise the fitting between simulated and observed response spectra and peak ground acceleration pga values we constrained the initial model of our inversion by using the heterogeneous slip distribution obtained from a kinematic inversion of the source of previous studies we used all the observed near fault ground motions 100 m from the borehole strong motion network of japan kik net which are little affected by surficial geology site effects the calculation of broadband frequency strong ground motion 0 1 10 hz is achieved by applying a hybrid technique that combines a deterministic simulation of the wave propagation for the low frequencies and a semi stochastic modelling approach for the high frequencies for the simulation of the high frequencies we introduce a frequency dependent radiation pattern model that efficiently removes the dependence of the pattern coefficient on the azimuth and take off angle as the frequency increases the good agreement between the observed and simulated broadband ground motions shows that our inversion procedure is successful in estimating the optimum asperity parameters of the tottori earthquake and provides a good test for the strong ground motion simulation technique the ratio of background stress drop to average asperity stress drop from our inversion is nearly 50 in agreement with the theoretical asperity model of das and kostrov das s kostrov b v 1986 fracture of a single asperity on a finite fault a model for weak earthquakes earthquake source mechanics agu pp 91 96 and an empirical ratio of asperities to rupture area seismol res lett 70 1999 59 80 the simulated radiation pattern is very complex for epicentral distances within half the fault length but it approaches the radiation of a double couple point source for larger distances the rupture velocity and rise time have a significant influence on the peak ground velocity pgv distribution around the fault an increase in rupture velocity produces a similar effect on the ground motion as a reduction in rise time

on the cause of the 1908 messina tsunami southern italy 1 a century after the catastrophic event the sources of the 1908 messina southern italy earthquake and tsunami which caused at least 60 000 deaths remain uncertain through a simple backward ray tracing method we convert the tsunami travel time data reported in a 100 years old paper into distances and find that the sources of the earthquake and tsunami are different overturning a long held assumption reconsideration of the available tsunami bathymetric seismic and seismological data indicates that the tsunami was generated by an underwater landslide

using an ultra long range terrestrial laser scanner to monitor the net mass balance of urumqi glacier no 1 eastern tien shan china at the monthly scale we describe the use of a terrestrial laser scanner tls to monitor the net mass balance of urumqi glacier no 1 eastern tien shan we used an ultra long range riegl vz 6000 tls which is specially designed for surveying snow and ice covered terrain to create repeated high spatiotemporal resolution dems focusing on the monthly scale 25 april 28 may 2015 net mass balance according to the tls derived dems the area of urumqi glacier no 1 was 1 558 km 2 on 25 april 2015 and the average surface elevation change was 0 225 m by comparing the results from the use of tls with the conventional glaciological mass balance method the correlation coefficient r 2 between glaciological elevation changes of individual stakes and the tls derived geodetic elevation change of corresponding points was 0 85 considering the uncertainty of both methods this is a promising result using the in situ measured snow densities snow pits of the glacier surface the geodetic net mass balance was 0 074 m w e which is slightly positive the mean uncertainty in the tls derived monthly net mass balance was 0 018 m w e showing that the tls surveying system presented accurate and relevant results and is therefore suitable to monitor mass balance evolution of mountain glaciers

organic matter preservation on continental slopes importance of mineralogy and surface area abstract theoretical considerations calculations and data reported by keil et al 1994a were used to assess the recent hypotheses that mineral surface roughness controls the specific surface area of continental margin sediments and that the matrix linked organic carbon content of continental margin sediments occurs as a monolayer or monolayer equivalent coating of organic compounds on the surfaces of detrital minerals and other detrital nonorganic grains mayer 1994 results of our analysis indicate that it is not the surface roughness of the terrigenous detrital framework grains that controls the specific surface area of most continental margin sediments even in the sand and silt fractions but rather the presence of nonspherical high surface area to volume particles primarily clays but also oxy hydroxides and ultra structured nonorganic bioclasts such as diatom frustules analysis of the mineralogy organic carbon content surface area and in situ microfabric of continental margin sediments off california in the mendocino and san luis obispo areas and off the state of washington indicate a strong correlation between the amount of matrix linked organic matter present and the suite of clay minerals data indicate that organic carbon appears to be preferentially sequestered in smectite rich sediments compared to those whose clay fractions are dominated by chlorite we suggest that this association is a function of differences in the site density and chemistry of the clays and differences in their flocculation behavior our data also indicate that organic carbon preservation on the three california transects all of which have a suboxic oxygen minimum zone that impinges on the sea floor is not significantly influenced by differences in bottom water oxygen concentration and carbon stable isotope data suggest no preferential preservation of continental organic matter over that of marine origin

estimation of the high frequency radiation of the 2000 tottori japan earthquake based on a dynamic model of fault rupture application to the strong ground motion simulation abstract in the present study we investigate the high frequency hf radiation mechanism of the 2000 tottori earthquake in japan based on a 3d spontaneous fault rupture dynamic model we generalize the model of hf radiation of a suddenly stopping circular crack madariaga 1977 boatwright 1982 to the radiation from a general 3d rupture in a planar fault where hf is radiated during gradual changes of rupture velocity at the rupture front local rupture velocity changes are expressed as the divergence of local rupture velocity vectors that are derived from gradients of rupture times from the dynamic model our numerical model of the tottori earthquake indicates that rupture velocity changes are largely induced by barriers locally stronger fault sections across the fault plane and that hf radiation mainly originates within asperities large stress drop regions in areas where the product of dynamic stress drop and rupture velocity changes is maximum we develop a strong ground motion simulation methodology that incorporates hf radiation inferred from a dynamic fault rupture model using this methodology we investigate the hf radiation of the tottori earthquake by inverting observed near source acceleration envelopes of the earthquake our inversion results corroborate that hf radiation originates within asperities and show that significant hf radiation represents no more than a 20 of the total asperity area our results show that the incorporation of a directivity factor on the basis of a well defined physical rupture model to the radiation pattern leads to a significant improvement in fitting of observed ground motions our simulated near source strong ground motions of the tottori earthquake are also able to reproduce the 2 radiation theoretically predicted in 2d dynamic fault rupture models

a transient simulation of precession scale spring dust activity over northern china and its relation to mid latitude atmospheric circulation abstract dust aerosol plays an important role in energy and water cycles of the earth system across multiple spatial and temporal scales and it is also a key factor in determining air quality in arid and semi arid areas of asia spring is the season of peak dust activity i e emission transport and sedimentation in asia however on the earth s orbit scale spring dust activity in northern china nc and its relationship with atmospheric circulation have seldom been investigated we present the results of an analysis of the evolution characteristic on the astronomical timescale and dynamic mechanism of spring dust activity in nc based on a transient numerical simulation over the past 150 kyr spanning multiple precessional cycles we found that within the precessional band spring dust transport is in phase with insolation the upper westerly jet on the north nwj of the tibetan plateau tp surface wind and heating of the tp whereas it is out of phase with siberian high sh atmospheric precipitation and soil water during the high insolation stage the nwj is strengthened by the thermal forcing of the tp which causes a northward shift of the location of the westerly jet so that dust activity is enhanced by the propagation of upper level waves meanwhile during the high insolation stage the instability of the lower atmosphere is increased due to the strengthening of the northerly wind associated with the weakening of the sh and surface warming together with their higher interaction with the nwj giving rise to dust mobilization in the asian arid and semi arid source areas and vice versa rainfall and soil moisture have little influence on the dust cycle on the orbital scale although modern observations show they have an important inhibitory effect on dust emission

processes and behaviors of block topple avalanches resulting from carbonate slope failures due to underground mining major rock landslides are the main type of geological hazards in the mountainous areas of southwestern china in which failure modes and behaviors are compounded in this study field surveys centrifuge modelling and numerical simulations were utilized to analyze the failure process of a steep dip and layered carbonate slope which was induced by underground goaf these included gravitational bending interlayer faulting topple failure of the upper blocks due to underground mining shearing through the underlying slide resistant rocks and catastrophic avalanches it was concluded that the bending and compaction of the weak interbedded coal seam had occurred on the slope with the effects of gravity the support for the overburden rocks was lost following the underground mining activities which led to bedding separation and the generation of cracks the upper blocks acted on blocks at the toe and shear failure at the toe was initiated when the force along the joints exceeded the anti shear strength which gradually formed an intact failure surface then a rock slide took place which transformed into a catastrophic rock avalanche the failure process was validated using a flac3d simulation and centrifuge testing

sensitivity analysis for finite difference seismic basin modeling a case study for kinburn basin ottawa canada we used a finite difference modeling method to investigate the sensitivity of the ground motion simulation results to the main input parameters including the source model regional path properties and local site conditions we used a spectral frequency range of 0 1 1 hz for the kinburn bedrock topographic basin ottawa canada for the ladysmith earthquake mw 4 7 some findings are known facts however the unique geophysical conditions in the ottawa area such as the high contrast between the shear wave velocities of the bedrock and the shear wave velocity of the soil were the reason for a comprehensive sensitivity analysis using a gaussian source function with a short half duration increased the peak ground velocities pgvs and the amplitude of the velocity fourier spectrum relaxation times and relaxation coefficients for the viscoelastic simulation significantly increased the amplitude of later arrivals at the soil site which consequently led to an increase in pgv the amplitude of the pseudospectral acceleration psa ratio and the velocity fourier spectrum for a small earthquake employing a small soil q model damped a significant amount of energy of the waves in the basin thus pgv the psa of soil to rock ratios and the velocity fourier spectrum were dependent on the soil q model also using a high velocity contrast between soil and rock increased pgvs and the amplitude of the psa of the soil to rock ratios whereas the frequency content of the waves shifted toward lower frequencies using a finite fault source model for a scenario large earthquake mw 7 significantly reduced the pgv values relative to a point source model using nonlinear viscoelastic simulation for a large earthquake mw 7 reduced the amplitude of the later arrivals and the amplitude of the psa of the soil to rock ratios and shifted the frequency content of waves toward lower frequency

the database of individual seismogenic sources diss version 3 summarizing 20 years of research on italy s earthquake geology abstract this paper describes the main characteristics the evolution and the structure of the database of individual seismogenic sources diss and particularly of its release of early 2007 the database contains the results of the investigations of the active tectonics in italy during the past 20 years the first two sections of this paper document the recent evolution in mapping and archiving italian active fault data in relation to important achievements in the understanding of italian tectonics some of which were spurred by significant earthquakes the central sections describe the current structure of the database the reasons for its assumptions and data categories its current contents its evolution through several years of improvements the last section describes how the current contents of the database correspond with the existing strain and stress data available from focal mechanism borehole breakout and gps data for the whole of italy the database supplies a fresh and unified view of active and seismogenic processes in italy by building on basic physical constraints concerning rates of crustal deformation on the continuity of deformation belts and on the spatial relationships between adjacent faults both at the surface and at depth

stochastic simulation of strong motion records from the 26 september 1997 mw 6 umbria marche central italy earthquake we simulated the strong motion time histories recorded during the main shock m w 6 0 of the umbria marche seismic sequence central italy of september october 1997 ground motion waveforms were computed using the stochastic modeling technique proposed by beresnev and atkinson 1997 1998 for finite faults in this approach the high frequency amplitudes are simulated as a summation of stochastic point sources we used the finsim code beresnev and atkinson 1998 which incorporates regional attenuation and frequency dependent site amplification factors we divided the fault plane into 60 elements whose length and width are 1 2 km and 1 5 km respectively the resulting subfault corner frequency and rise time are 0 91 hz and 0 5 sec we found that the site amplification functions play an important role in the simulation process improving the fit to the observed time histories and spectra the strong motion waveforms recorded at the nocera noc station located at the northern end of the causative fault show an important directivity effect thus to fit the observed ground motions we used an inhomogeneous slip distribution weighting the slip on the fault heavier toward the north we tested two models one that simulates a fault rupture with two main slip patches and a second model that ruptures northward with a less heterogeneous slip distribution where slip is mostly concentrated near the rupture nucleation at the southern edge of the fault plane the simulated low frequency amplitudes at noc however require an additional frequency dependent directivity correction e g bernard et al 1996 in conclusion we found that stochastic finite fault simulations calculated using adequate site amplification functions and crustal attenuation reproduce reasonably well the ground motions from the m w 6 0 umbria marche earthquake

influence of underground mining activities on the slope deformation genesis doubrava vrchovec doubrava ujala and staric case studies from czech republic abstract one the most important manifestation of underground mining activities is its potential influence on the initiation and reactivation of the slope movements however an adequate attention has not yet been paid to these problems the goal of this study is to analyze the possible influence of present and former mining activities on the selected set of model slope deformations in the ostrava karvina coalfield and also to describe a methodology for their observation for the application to similar conditions and influence three different methodologies applied in three different case studies of slope deformations where the subsidences are still active in the first case study doubrava vrchovec inclinometer was not used in the second doubrava ujala case study only one inclinometer was installed in landslide body and in the third case study sta ic two inclinometers were installed as one of them was inside of the landslide body while the other inclinometer was outside for evaluation of the impact isocatabase maps terrain deformation parameters calculated for the point lying on the slope deformation surface length measurement by zone extensometer and dilatometer measurement in cracks was also provided in order to show that inclination of both boreholes is an evidence of underground mining impact localization of inclinometer measurement on boreholes in the active part as well as in the near vicinity was found as very important thus the study contributed to a more objective knowledge of these problems of interest for the professional public and also for the state administration to solve problems associated with the utilization and settlement of such affected areas

organic matter preservation on the pakistan continental margin as revealed by biomarker geochemistry in order to assess whether the oxygen minimum zone omz in the arabian sea has an eaect on the preservation and composition of organic matter in surface sediments we investigated samples from three diaerent transects on the pakistan continental margin across the omz in addition to determining the total amount of organic carbon toc we analyzed the extractable lipids by gas chromatography combined gas chromatography mass spectrometry and compound specific stable carbon isotope measurements the extractable lipids are dominated by marine organic matter as indicated by the abundance of lipids typical of marine biota and by the bulk and molecular isotopic composition sediments from within the omz are enriched in organic carbon and in several extractable lipids i e phytol n alcohols total sterols n c35 alkane relative to stations above and below this zone other lipid concentrations such as those of total n fatty acids and total n alkanes fail to show any relation to the omz only a weak correlation of toc with mineral surface area was found in sediments deposited within the omz in contrast sediments from outside the omz do not show any relationship between toc and surface area among the extractable lipids only the n alkane concentration is highly correlated with surface area in sediments from the hab and makran transects in sediments from outside the omz the phytol and sterol concentrations are also weakly correlated with mineral surface area the depositional environment of the indus fan oaers the best conditions for an enhanced preservation of organic matter the omz together with the undisturbed sedimentation at moderate rates seems to be mainly responsible for the high toc values in this area overall the type of organic matter and its lability toward oxic degradation the mineral surface area the mineral composition and possibly the secondary productivity by sedimentary bacteria also appear to have an influence on organic matter accumulation and composition 2000 elsevier science ltd all rights reserved

modeling strong ground motion in the wellington metropolitan area new zealand the wellington metropolitan area new zealand about 35 km by 10 km is crossed by the southernmost segment of the wellington fault striking roughly in the northeast southwest direction numerical modeling of m 6 7 earthquakes due to ruptures on this fault intended to characterize the 3d effects of the region9s main geological features on the ground motion are performed by using a finite differences scheme with staggered grid for frequencies up to 1 5 hz we consider the part of the wellington fault that crosses the wellington metropolitan region as an almost vertical strike slip fault 30 km long and with slip distribution history taken from the slip history of the 1992 m 7 3 landers california earthquake the 3d stratigraphy of the region has been built by integrating all available geological and geophysical data results of the modeling show several dominant features when the fault ruptures from south to north resonance occurs within a small area close to the harbor where the depth of the basin is largest this resonance produces a train of seismic waves traveling northward with dominant frequency of about 0 5 hz as the rupture propagates into the harbor the radiated wavefield focuses on the lower hutt valley to the north due to the presence of a ridge that rises up from the bottom of the harbor to emerge as somes island this effect considerably enhances the incident seismic energy in the valley particularly the horizontal motions further focusing occurs due to the triangular shape of the lower hutt valley whose alluvial deposits exhibit large impedance contrasts with the surrounding bedrock the combined focusing effects produce amplification factors in the valley of about 5 between 0 5 hz and 0 7 hz in wellington city the amplification factors are between 0 5 deamplification and 2 except for an area on reclaimed land in the harbor which shows an amplification factor as large as 9 after the rupture has stopped higher frequency waves between 1 and 1 2 hz appear trapped reverberating in the harbor for the remaining duration of the seismograms up to 60 sec on the other hand when the rupture is from north to south none of the focusing effects occur only the long lasting reverberations in the harbor seem a characteristic of the wave propagation common to both rupture directions nevertheless the amplification factors in this north to south scenario are about the same as for the south to north rupture online material movies of wellington fault rupture scenarios

stochastic fault stress implications for fault dynamics and ground motion up to the present time ground motion calculations for future earthquakes have almost exclusively been made from kinematic models however dynamic faulting models offer many benefits over kinematic models including the assurance the faulting models obey at least the general rules of elastodynamics and friction and contain a natural relationship between stress drop slip rise time and rupture velocity dynamic models also offer insight into the physics of the rupture and slip processes and can show how these processes lead to patterns of ground motion in the current work we use the 3d finite difference method and a suite of stochastic stress patterns with variable assumptions on strength and stress inhomogeneity to investigate two issues 1 the effect of assumptions about stress pattern on the evolution of rupture and slip on the fault and 2 the effect of these assumptions on the resultant ground motion we find that stress drop has a complicated relationship with slip rise time and rupture velocity especially in faults with strongly heterogeneous strength we also find that these inhomogeneous strength faults can produce highly inhomogeneous slip even without any form of frictional restrengthening at healing time finally we find that smoother strength models produce a better fit than the coarse models to the directivity pulse often observed on the surface the results help to shed light on the transition of the faulting system between locally controlled and more globally controlled rupture and also show how dynamic models may be used to generate ground motion estimates for seismic hazard calculations

sensitivity of broad band ground motion simulations to earthquake source and earth structure variations an application to the messina straits italy summary in this paper we investigate ground motion variability due to different faulting approximations and crustal model parametrizations in the messina straits area southern italy considering three 1 d velocity models proposed for this region and a total of 72 different source realizations we compute broad band 0 10 hz synthetics for mw 7 0 events using a fault plane geometry recently proposed we explore source complexity in terms of classic kinematic constant rise time and rupture speed and pseudo dynamic models variable rise time and rupture speed heterogeneous slip distributions are generated using a von karman autocorrelation function rise time variability is related to slip whereas rupture speed variations are connected to static stress drop boxcar triangle and modified yoffe are the adopted source time functions we find that ground motion variability associated to differences in crustal models is constant and becomes important at intermediate and long periods on the other hand source induced ground motion variability is negligible at long periods and strong at intermediate short periods using our source modelling approach and the three different 1 d structural models we investigate shaking levels for the 1908 mw 7 1 messina earthquake adopting a recently proposed model for fault geometry and final slip our simulations suggest that peak levels in messina and reggio calabria must have reached 0 6 0 7 g during this earthquake

organic matter sources and early diagenetic alterations in arctic surface sediments lena river delta and laptev sea eastern siberia ii molecular and isotopic studies of hydrocarbons abstract the hydrocarbons extracted from three surface sediment samples from the delta of the lena river and adjacent areas of the laptev sea were examined to derive information on their source s natural vs anthropogenic terrestrial vs marine the abundance nature distribution and individual stable carbon isotope ratios of these hydrocarbons were determined it thus appeared that the laptev samples are characterized by i a negligible level of oil pollution due to anthropogenic and or natural petrogenic inputs ii an almost exclusive occurrence of long chain predominantly odd carbon numbered n alkanes and iii some differences in the level of bacterial alteration with a relatively higher degradation of the n alkanes in the seaward sediment a non terrestrial origin is proposed for these n alkanes based on the present results and on previous observations on carboxylic acid moieties and the pyrolysis products of the three surface sediments such hydrocarbons are probably not derived from the epicuticular waxes of higher plants but chiefly correspond to autochthonous products likely of algal origin these observations added to recent results on samples from other types of marine environments stress that an abundance of long chain predominantly odd n alkanes in extracts should not be systematically considered alone as evidence for a major contribution of higher plant waxes the relatively low contribution of terrestrial n alkanes in the laptev sediments should result from the combination of i a major dilution of the terrestrial input due to high primary productivity in summer promoted both by a large influx of nutrients provided by the lena river and by the specific conditions in such an arctic environment and ii the high level of degradation of the organic material transported by the lena river thus the latter probably provided a low input of lipids from terrestrial sources to the laptev samples

terrestrial vegetation change inferred from n alkane σ13c analysis in the marine environment abstract we report gas chromatography isotope ratio monitoring mass spectrometry gc irm ms measurements of the 13c values of individual biomarker compounds n alkanes extracted from a 3 m marine sediment core taken near the mouth of the johnstone river north queensland australia the technique allows a purely terrestrial isotope signal to be discerned despite mixing of terrestrial and marine derived carbon the results indicate that there has been a 2 increase in the 13c values of terrestrially derived n alkanes c29 c33 since clearing of the forested johnstone river drainage basin for sugarcane and pasture began in the late 19th century a much slower 1 increase in 13c values after 6 000 years bp and prior to european settlement may be related to a decrease in rainfall in the basin or to an increase in the abundance of c4 plants as a result of increased aboriginal burning the results from the sediment core are consistent with data obtained for modern river sediments from forested and cleared subcatchments within the basin and demonstrate that the 13c values of terrestrially derived n alkanes in the marine environment can be used to assess basin wide vegetation changes in adjacent river catchments on geological timescales

attenuation study in the straits of messina area southern italy abstract the attenuation of seismic waves is one of the basic physical parameters used in seismological studies and earthquake engineering which is closely related to the seismicity and regional tectonic activity of a particular area in this work the seismic attenuation in the straits of messina affected by several and strong historical earthquakes was studied using waveforms recorded by a local seismic network composed of seven stations we measured the coda quality factor q c in the single scattering model hypothesis the direct quality factor q d applying the coda normalization method for s waves and the intrinsic and scattering quality factor q i and q s by the multiple lapse time window analysis mltwa method coda q values were obtained using different lapse times 40 60 and 80 s for the frequency bands centred at 1 5 3 6 and 12 hz our findings indicate that q c increases with increasing lapse time and that q c is frequency dependent this behaviour is usually correlated to the degree of tectonic complexity and to the presence of heterogeneities at several scales in fact by using the coda normalization method we obtained low q d values as expected for a heterogeneous and active zone finally by the mltwa method we observe that the contribution of the scattering attenuation q s 1 prevails on the intrinsic absorption q i 1 until 3 hz conversely q i 1 and q s 1 seem to be of the same order in the higher frequency bands