hybrid modeling of p sv seismic motion at inhomogeneous viscoelastic topographic structures a new hybrid two step method for computation of p sv seismic motion at inhomogeneous viscoelastic topographic structure is presented the method is based on a combination of the discrete wavenumber dw finite difference fd and finite element fe methods in the first step the dw method is used to calculate the source radiation and wave propagation in the background 1d medium in the second step the fd fe algorithm is used to compute the wave propagation along the topographic structure the accuracy of the method has been separately tested for inclusion of the attenuation and for inclusion of the free surface topography through numerical comparisons with analytical and independent numerical methods the method is a generalization of the hybrid dw fd method of zahradnik and moczo 1996 for localized structures with a flat free surface numerical computations for a ridge sediment valley and the ridge neighboring the sediment valley show that a ridge can considerably influence the response of the neighboring sediment valley this means that the neighboring topographic feature should be taken into account even when we are only interested in the valley response

foam rubber modeling of topographic and dam interaction effects at pacoima dam a study of the topographic and dam interaction effects was made using a 3 d foam rubber model of the actual topography around the pacoima dam accelerograph which recorded over 1 g high frequency horizontal ground accelerations during the 1971 san fernando earthquake scaling of frequency from the model to the earth depends on the average value of shear wave velocity in the upper few hundred meters assuming e 2 km sec for vertically incident sh waves the spectral ratio of the ground acceleration on the ridge to the free field flat surface indicates an amplification of about 60 per cent around 6 5 hz on the n76 w component topography has little effect upon the motion recorded on the s14 w component motion on the ridge is lower than the free field motion on both horizontal components for frequencies above 9 hz amplification peaks shift to higher or lower frequencies depending on the assumed shear wave velocity in the upper few hundred meters results from nonvertically incident sh waves show that the topographic effect is dependent on the direction of approach of the seismic energy the effect is either de amplification in part by shadowing or amplification relative to the case where no topography is present depending on whether the canyon is on the ray path or not the fourier spectrum of the ground motion at the dam crest shows peak frequencies at about 5 hz and 10 hz resonance which correspond to the normal modes of the dam a study of dynamic interaction between the pacoima dam and the ridge shows that the coupling is less than 2 per cent at about 10 hz and less than 12 percent at about 5 hz

topographical and geological amplifications determined from strong motion and aftershock records of the 3 march 1985 chile earthquake site response experiments were performed 5 months after the ms 7 8 central chile earthquake of 3 march 1985 to identify amplification due to topography and geology topographical amplification at canal beagle a subdivision of vina del mar was hypothesized immediately after the main event when extensive damage was observed on the ridges of canal beagle using frequency dependent spectral ratios of aftershock data obtained from a temporarily established dense array it is shown that there is substantial amplification of motions at the ridges of canal beagle the data set constitutes the first such set depicting topographical amplification at a heavily populated region and correlates well with the damage distribution observed during the main event dense arrays established in vina del mar also yielded extensive data which are quantified to show that in the range of frequencies of engineering interest there was substantial amplification at different sites of different geological formations to substantiate this spectral ratios developed from the strong motion records of the main event are used to show the extensive degree of amplification at an alluvial site as compared to a rock site similarly spectral ratios developed from aftershocks recorded at comparable stations qualitatively confirm that the frequency ranges for which the amplification of motions occur are quite similar to those from strong motion records in case of weak motions the denser arrays established temporarily as described herein can be used to identify the frequency ranges for which amplification occurs to quantify the degree of frequency dependent amplification and used in microzonation of closely spaced localities

estimation of q for long period 2 sec waves in the los angeles basin we simulate 0 to 0 5 hz 3d wave propagation through the southern california earthquake center seismic velocity reference model version 2 for the 1994 northridge earthquake in order to examine the effects of anelastic attenuation and amplification within the near surface sediments we use a fourth order finite difference staggered grid method with the coarse grained frequency independent anelastic scheme of day and bradley 2001 and a variable slip distribution from kinematic inversion for the northridge earthquake we find that the near surface material with s wave velocity v s as low as 500 m sec significantly affects the long period peak ground velocities compared with simulations in which the s wave velocity is constrained to 1 km sec and greater anelastic attenuation also has a strong effect on ground motion amplitudes reducing the predicted peak velocity by a factor of up to 2 5 relative to lossless simulations our preferred q model is q s v s 0 02 v s in meters per second for v s less than 1 2 km sec and much larger q s v s 0 1 v s in meters per second for layers with higher velocities the simple model reduces the standard deviation of the residuals between synthetic and observed natural log of peak velocity from 1 13 to 0 26 relative to simulations for the lossless case the anelastic losses have their largest effect on short period surface waves propagating in the los angeles basin which are principally sensitive to q s in the low velocity near surface sediments of the basin the low frequency ground motion simulated here is relatively insensitive to q p as well as to the values of q s at depths greater than roughly that of the 2 km sec s wave velocity isosurface

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

isotopic composition of pb in ore deposits of the betic cordillera spain origin and relationship to other european deposits the betic cordillera in southern spain is a complex alpine fold belt that resulted from the cretaceous through cenozoic collision of africa with europe the region is illustrative of one of the characteristics of the alpine mediterranean orogen the occurrence over a limited area of mineral deposits with a wide variety of host rocks mineralization ages and styles the metamorphic basement in the betic zone is characterized by a nappe structure of superimposed tectonostratigraphic units and consists of lower paleozoic to lower triassic clastic metasedimentary rocks this is overlain by middle to upper triassic platform carbonate rocks with abundant strata bound f pb zn ba deposits e g sierra de gador sierra alhamilla cretaceous to paleogene subduction related compression in southeastern spain was followed by miocene postcollisional extension and resulted in the formation of the almeria cartagena volcanic belt and widespread hydrothermal activity and associated polymetallic mineralization typical miocene hydrothermal deposits include volcanic hosted au e g rodalquilar and ag rich base metal e g cabo de gata mazarron deposits as well as complex polymetallic veins mantos and irregular replacement bodies which are hosted by paleozoic and mesozoic metamorphic rocks and neogene sedimentary and volcanic rocks e g cartagena sierra almagrera sierra del aguilon loma de bas lead isotope compositions were measured on sulfide samples from nine ore districts and from representative fresh samples of volcanic and basement rock types of the region the results have been used to evaluate ore forming processes in southeastern spain with emphasis on the sources of metals during a late triassic mineralizing event pb was leached from paleozoic clastic metasedimentary rocks and incorporated in galena in strata bound f pb zn ba deposits 206 pb 204 pb 18 332 or 12 207 pb 204 pb 15 672 or 12 208 pb 204 pb 38 523 or 46 the second episode of mineralization was essentially contemporaneous late miocene throughout the region and did not involve remobilization of less radiogenic triassic ore pb lead isotope data indicate a dominantly paleozoic metasedimentary source for polymetallic vein and manto type deposits that formed by hydrothermal circulation through the betic basement driven by miocene intrusions 206 pb 204 pb 18 747 or 20 207 pb 204 pb 15 685 or 9 208 pb 204 pb 39 026 or 37 lead in au cu te sn ores is isotopically indistinguishable from that of the calc alkalic volcanic host 206 pb 204 pb 18 860 or 9 207 pb 204 pb 15 686 or 8 208 pb 204 pb 38 940 or 27 in contrast the pb in volcanic hosted pb zn cu ag au veins was derived from paleozoic metamorphic and miocene volcanic rocks 206 pb 204 pb 18 786 or 5 207 pb 204 pb 15 686 or 2 208 pb 204 pb 38 967 or 9 a comparison of the pb isotope data from southeastern spain with published data from selected pb zn deposits in southern europe including les malines l argentiere and the alpine iglesiente sulcis and montagne noire districts indicates the importance of a metasedimentary basement as a common source of ore pb

lead in the getchell turquoise ridge carlin type gold deposits from the perspective of potential igneous and sedimentary rock sources in northern nevada implications for fluid and metal sources lead isotope compositions of bulk mineral samples fluorite orpiment and realgar determined using conventional techniques and of ore stage arsenian pyrite using the sensitive high resolution ion microprobe shrimp in the getchell and turquoise ridge carlin type gold deposits osgood mountains require contribution from two different pb sources one pb source dominates the ore stage it has a limited pb isotope range characterized by 208pb 206pb values of 2 000 to 2 005 and 207pb 206pb valuesof 0 8031 to 0 8075 as recorded by 10 mm diameter spot shrimp analyses of ore stage arsenian pyrite these values approximately correspond to 206pb 204pb of 19 3 to 19 6 207pb 204pb of 15 65 to 15 75 and 208pb 204pb of 39 2 to 39 5 this pb source is isotopically similar to that in average neoproterozoic and cambrian clastic rocks but not to any potential magmatic sources whether those clastic rocks provided pb to the ore fluid cannot be unequivocally proven because their pb isotope compositions over the same range as in ore stage arsenian pyrite are similar to those of ordovician to devonian siliciclastic and calcareous rocks the pb source in the calcareous rocks most likely is largely detrital minerals since that detritus was derived from the same sources as the detritus in the neoproterozoic and cambrian clastic rocks the second pb source is characterized by a large range of 206pb 204pb values 18 34 with a limited range of 208pb 204pb values 38 1 39 5 indicating low but variable th u and high and variable u pb values the second pb source dominates late and postore stage minerals but is also found in preore sulfide minerals these pb isotope characteristics typify ordovician to devonian siliciclastic and calcareous rocks around the carlin trend in northeast nevada petrologically similar rocks host the getchell and turquoise ridge deposits lead from the second source was either contributed from the host sedimentary rock sequences or brought into the hydrothermal system by oxidized ground water as the system collapsed late ore and postore stage sulfide minerals pyrite orpiment and stibnite from the betze post and meikle deposits in the carlin trend and from the jerritt canyon mining district have pb isotope characteristics similar to those determined in getchell and turquoise ridge this observation suggests that the pb isotope compositions of their ore fluids may be similar to those at getchell and turquoise ridge two models can explain the pb isotope compositions of the ore stage arsenian pyrite versus the late ore or postore sulfide minerals in either model pb from the ordovician to devonian siliciclastic and calcareous rock source enters the hydrothermal system late in the ore stage but not to any extent during the main stage of ore deposition in one model ore stage pb was derived from a source with pb isotope compositions similar to those of the neoproterozoic and cambrian clastic sequence transported as part of the ore fluid and then deposited in the ore stage arsenian pyrite and fluorite the second model is based on the observation that the pb isotope characteristics of the ore stage minerals also are found in some ordovician to devonian calcareous and siliciclastic rocks hence ore stage pb could have been derived locally and simply concentrated during the ore stage critical to the second model is the removal of all high 206pb 204pb 20 material during alteration it also requires the retention of only the low 206pb 204pb component of the ordovician to devonian sedimentary rocks this critical step is possible only if the high 206pb 204pb values are contained in readily dissolvable mineral phases whereas the low 206pb 204pb values are found only in refractory minerals that released pb during a final alteration stage just prior deposition of auriferous arsenian pyrite distinguishing between pb transported with the ore fluid or inherited from the site of mineral deposition is not straightforward however it is simpler to explain the pb isotope compositions of ore stage arsenian pyrite and fluorite in two different but spatially related carlin type deposits getchell and turquoise ridge with different host rocks by input of pb with the ore fluid once the limited pb in the hydrothermal fluid was exhausted by incorporation in ore stage arsenian pyrite or other ore stage minerals pb from the second source the ordovician to devonian sedimentary rock sequences became available for incorporation in some but not all of the late stage sulfide minerals

ground motion observations at hotel montana during the m 7 0 2010 haiti earthquake topography or soil amplification unusually severe structural damage was reported during the 2010 m 7 0 haiti earthquake in the vicinity of hotel montana located on top of a ridge in the district of petionville prompted by the observations u s geological survey seismic stations were deployed and aftershock recordings indicated ground motion amplification on the top of the hill compared to adjacent stations on reference site conditions the presence of topographic relief has been shown to significantly aggravate the consequences of strong ground motion during past events and topographic effects were brought forward to explain the observations in this paper we test the hypothesis of topographic amplification as the dominant factor that contributed to the damage concentration in the vicinity of hotel montana we initially conduct numerical simulations of the ridge seismic response assuming elastic homogeneous site conditions and show that numerical predictions of topographic amplification disagree with the field data both in amplitude and in frequency conversely while 1d ground response analyses for the site conditions at the hilltop predict amplification in the same frequency range as the field data they significantly underestimate the recorded amplitude we then conduct numerical simulations of the foothill ridge response to seismic motion while accounting for soil layering and qualitatively demonstrate that the recorded amplification is most likely attributed to coupled site topographic amplification effects namely to seismic waves trapped in the soft soil layers of the near surface amplified as a consequence of reverberations and further modified due to diffraction and scattering upon incidence on the irregular ground surface parametric investigations of the topography soil amplification coupling effects are then conducted and our results show that when accounting for a hypothetical soil bedrock interface at 100 m depth predictions are in excellent agreement with the observed motion

effects of realistic surface topography on seismic ground motion in the yangminshan region of taiwan based upon the spectral element method and lidar dtm we combine light detection and ranging lidar digital terrain model dtm data and an improved mesh implementation to investigate the effects of high resolution surface topography on seismic ground motion based upon the spectral element method in general topography increases the amplitude of shaking at mountain tops and ridges whereas valleys usually have reduced ground motion as has been observed in both records from past earthquakes and numerical simulations however the effects of realistic topography on ground motion have not often been clearly characterized in numerical simulations especially the seismic response of the true ground surface here we use lidar dtm data which provide two meter reso lution at the free surface and a spectral element method to simulate three dimensional 3d seismic wave propagation in the yangminshan region in taiwan incorporating the effects of realistic topography a smoothed topographic map is employed beneath the model surface in order to decrease mesh distortions due to steep ground surfaces numerical simulations show that seismic shaking in mountainous areas is strongly affected by topography and source frequency content the amplification of ground motion mainly occurs at the tops of hills and ridges whilst the valleys and flat topped hills experience lower levels of ground shaking interaction between small scale to pographic features and high frequency surface waves can produce unusually strong shaking we demonstrate that topographic variations can change peak ground accel eration pga values by 50 in mountainous areas and the relative change in pga between a valley and a ridge can be as high as a factor of 2 compared to a flat surface response this suggests that high resolution realistic topographic features should be taken into account in seismic hazard analysis especially for densely populated moun tainous areas

the origin of large gypsum crystals in the geode of pulpi almeria spain financial support was provided by projects cgl2010 16882 and cgl2010 12099 e ministerio de educacion y ciencia mec and cgl2016 78971 p mec we acknowledge logistic support from magi baselga the town council of pulpi and the junta de andalucia proyecto de excelencia rnm 5384 we are grateful to yves kruger for his assistance during monophase inclusion measurements van driessche acknowledges funding from the french national program ec2co biohefect sulfcycle

ground motion amplitude across ridges abstract local amplification and wave diffraction on an elongated ridge near sourpi in central greece were studied by the analysis of seismic records of local and regional earthquakes data were obtained during field work especially designed for this purpose these data were analyzed in the frequency and time domains in the frequency domain spectral ratios show amplifications of 1 5 to 3 at the ridge top relative to the base of the ridge the horizontal components of motion are more amplified than the vertical component and the observed spectral ratios seem stable for different earthquake locations theoretical spectral ratios calculated by the indirect boundary element method are dependent on earthquake location but are in general agreement with the observed spectral ratios another dataset from mont st eynard in the french alps showed similar characteristics with spectral amplitudes on the top of the ridge up to four times those on the flank these relative amplifications are within the range predicted by numerical simulations the numerical simulations also show that the topographic effect involves the emission of diffracted waves propagating from the top toward the base of the ridge the use of a seven station array on the ridge at sourpi made it possible to identify such waves the analysis was performed with wave separation methods using singular value decomposition and spectral matrix filtering our results show agreement between experimental data and theoretical results supporting the use of numerical simulations for estimation of purely topography induced amplification on ridge tops our results also show that such amplification is moderate for the ridges under study

structural control and geological significance of the zn pb ores formed in the benasque pass area central pyrenees during the post late ordovician extensional event of the gondwana margin abstract the benasque pass area central pyrenees is located in the eastern part of the variscan lys caillaouas massif where cambro ordovician rocks of the hesperian massif crop out in the area several zn pb deposits are located in variscan structures lead isotopes indicate a late ordovician early devonian model age for the deposits in the region an unconformity between pre late ordovician and late ordovician rocks has been defined by several authors and has been identified in the study area the first structures observed in the benasque pass area consist of a pre variscan cleavage which only affects the pre late ordovician rocks in the study area the main structures correspond to two variscan generations i e w trending north verging folds which are associated with the main foliation s 1 d 1 ii e w trending upright folds and associated small south directed thrusts d 2 d 2 structures are the ones hosting the zinc lead ore in the benasque pass area d 1 and d 2 variscan structures have developed under low grade metamorphic conditions some faults observed in the north and the south of the study area may have alpine movement in the benasque pass area the strongly silicified and brecciated zinc lead ore is mainly developed in the d 1 short limb of the mina peak syncline within which s 1 foliation is intensely folded and cross thrust by d 2 structures taking into account their model age all these zinc lead deposits seem to be stratiform stratabound or filling open spaces in origin and related to the pre variscan extension described for the central pyrenees however the zinc lead ore is hosted in strongly silicified and brecciated variscan structures the 34 s isotopic composition of sulfides indicates that the metamorphism and deformation did not completely obliterate the original isotopic composition suggesting that sulfur in the benasque pass has mainly come from the reduction of marine sulfate extracted from the rocks of the metasedimentary sequence in the benasque pass area the lead isotope ratios are homogeneous and have a pre variscan model age which is also the age of the host rocks in the case of the benasque pass the deposits occurred in variscan structures making it impossible to recognize their original pre variscan characteristics indicated by lead isotopes model age the correlation between the pb isotope data for deposits from the benasque pass and aran valley also located in the central pyrenees and those for other deposits from the southern european gondwana is evident and the isotopic data set closely fits the two stage pb evolution model for sardinia terrane the coherence of the pb isotope trends in all the deposits suggests that pb was extracted at various times from sources with similar time averaged u pb th pb and th u values through a process of leaching of the basement rocks by large volumes of hydrothermal fluids in the case of the pyrenees central and eastern the lead and other metals present in the deposit were extracted by hydrothermal fluids from the upper crust rocks during the post late ordovician extensional event of the gondwana margin

analysis of topographic amplification of inclined shear waves in a steep coastal bluff abstract the effect of inclined shear waves on the seismic response of a steep bluff is analyzed using generalized consistent transmitting boundaries the results of the frequency domain analysis of a stepped half space subjected to incident shear waves inclined from 0 to 30 show that the motion at the crest of the slope is amplified for waves traveling into the slope and attenuated for waves traveling away from the slope as compared to the motion in the free field behind the crest of the slope this amplification can be as much as twice that observed for vertically propagating waves a time domain analysis of bluffs at seacliff state beach california is used to estimate the effect of topography using realistic conditions taking into account wave inclination and site effects the analysis of the site shows that although topographic amplification does in fact nearly double the amplitude of the motion in some cases this amplification is offset by reduced site amplification and by wave splitting at material interfaces thus the actual peak acceleration occurring at the crest of the slope changes little with incident angle as compared to the amplification of the free field motion and actually decreases in many cases though a more general study is recommended these results suggest that wave orientation and inclination substantially increase topographic amplification however it may be adequate to only account for vertically propagating waves for site response and slope stability analyses where only the magnitude of acceleration is considered

an experimental topographic amplification study at los alamos national laboratory using ambient vibrations abstract an experimental study aimed at investigating potential topographic amplification of seismic waves was conducted on a 50 m tall and 185 m wide soft rock ridge located at los alamos national laboratory near los alamos new mexico ten portable broadband seismograph stations were placed in arrays across the ridge and left to record ambient vibration data for 9 hours clear evidence of topographic amplification was observed by comparing spectral ratios calculated from ambient noise recordings at the toe slope and crest of the instrumented ridge the inferred resonance frequency of the ridge obtained from the experimental recordings was found to agree well with several simple estimates of the theoretical resonance frequency based on its geometry and stiffness results support the feasibility of quantifying the frequency range of topographic amplification solely using ambient vibrations rather than strong or weak ground motions additionally comparisons have been made between a number of widely used experimental methods for quantifying topographic effects such as the standard spectral ratio median reference method and horizontal to vertical spectral ratio differences in the amplification and frequency range of topographic effects indicated by these methods highlight the importance of choosing a reference condition that is appropriate for the site specific conditions and goals associated with an experimental topographic amplification study

the effect of topography on earthquake ground motion a review and new results a brief review of experimental and theoretical results about the effect of topography on seismic motion shows that they are consistent only on a qualitative basis amplification at mountain tops for wavelengths comparable with mountain widths is predicted and observed but the numerical simulations often underestimate the actual observed effects we propose that this disagreement is because current models are not complex enough we therefore computed the response to incident sh waves of a set of different complex configurations that include two dimensional surface topography with or without periodic ridges and subsurface layering the results show that 1 the topographic effect in itself is difficult to isolate from other effects like surface layering and therefore the amplification on top of geomorphologically complex sites cannot be predicted by a priori estimations based solely on topography and 2 the high crest base amplification ratio observed in the field cannot usually be matched even with complex two dimensional structures with incident plane sh waves which suggests that more complex models are needed to incorporate more complex wave fields e g sv surface and three dimensional geologic configurations

lake sediment records of atmospheric pollution in the romanian carpathians abstract short lake sediment cores from ten lakes in the romanian carpathians have been characterised both mineral magnetically and geochemically providing an assessment of the potential of these mountain lakes sediment records as a retrospective indicator of atmospheric pollution mineral magnetic characteristics suggests that recent sediments have been affected by atmospheric particulate pollution associated with fossil fuel combustion and vehicle emissions although the properties may also reflect within lake processes metal enrichment factors for contemporary sediments reveal that remote mountain lakes in this region appear to have been impacted by the long range atmospheric transport of metallic pollutants the results suggest that sites in the southern mountains are most impacted although trace metal levels are relatively modest initial findings suggest that some sites have the potential to provide lake sediment based pollution histories that will thereby contribute to a fuller europe wide understanding of the impact of atmospheric pollutants in upland regions

role of shape and numbers of ridges and valleys in the insulating effects of topography on the rayleigh wave characteristics this research work is inspired by the recently accepted concept that high frequency rayleigh waves are generated in the epicentral zone of shallow earthquakes such high frequency rayleigh waves with large amplitude may develop much of spatial variability in ground motion which in turn may cause unexpected damage to long span structures like bridges underground pipelines dams etc in the hilly regions further it has been reported that topography acts as an insulator for the rayleigh waves ma et al bssa 97 2066 2079 2007 the above mentioned scientific developments stimulated to quantify the role of shape and number of ridges and valleys falling in the path of rayleigh wave in the insulating effect of topography on the rayleigh waves the simulated results reveals very large amplification of the horizontal component of rayleigh wave near the top of a triangular ridge which may cause intensive landslides under favorable condition the computed snapshots of the wave field of rayleigh wave reveals that the interaction of rayleigh wave with the topography causes reflection splitting and diffraction of rayleigh wave in the form of body waves which in turn provides the insulating capacity to the topography insulating effects of single valley is more than that of single ridge further this effect was more in case of elliptical ridge valley than triangular ridge valley the insulating effect of topography was proportional to the frequency of rayleigh wave and the number of ridges and valleys in the string the obtained level of insulation effects of topography on the rayleigh wave energy of rayleigh wave reduced to less than 4 after crossing a topography of span 4 5 km calls for the consideration of role of hills and valleys in seismic hazard prediction particularly in case of shallow earthquakes

directional topographic site response at tarzana observed in aftershocks of the 1994 northridge california earthquake implications for mainshock motions abstract the northridge earthquake caused 1 78 g acceleration in the east west direction at a site in tarzana california located about 6 km south of the mainshock epicenter the accelerograph was located atop a hill about 15 m high 500 m long and 130 m wide striking about n78 e during the aftershock sequence a temporary array of 21 three component geophones was deployed in six radial lines centered on the accelerograph with an average sensor spacing of 35 m station c00 was located about 2 m from the accelerograph we inverted aftershock spectra to obtain average relative site response at each station as a function of direction of ground motion we identified a 3 2 hz resonance that is a transverse oscillation of the hill a directional topographic effect the top base amplification ratio at 3 2 hz is about 4 5 for horizontal ground motions oriented approximately perpendicular to the long axis of the hill and about 2 for motions parallel to the hill this resonance is seen most strongly within 50 m of c00 other resonant frequencies were also observed a strong lateral variation in attenuation probably associated with a fault caused substantially lower motion at frequencies above 6 hz at the east end of the hill there may be some additional scattered waves associated with the fault zone and seen at both the base and top of the hill causing particle motions not spectral ratios at the top of the hill to be rotated about 20 away from the direction transverse to the hill the resonant frequency but not the amplitude of our observed topographic resonance agrees well with theory even for such a low hill comparisons of our observations with theoretical results indicate that the 3d shape of the hill and its internal structure are important factors affecting its response the strong transverse resonance of the hill does not account for the large east west mainshock motions assuming linear soil response mainshock east west motions at the tarzana accelerograph were amplified by a factor of about 2 or less compared with sites at the base of the hill probable variations in surficial shear wave velocity do not account for the observed differences among mainshock acceleration observed at tarzana and at two different sites within 2 km of tarzana

moving metals ii provenancing scandinavian bronze age artefacts by lead isotope and elemental analyses the first part of this research published previously proved without doubt that the metals dated to the nordic bronze age found in sweden were not smelted from the local copper ores in this second part we present a detailed interpretation of these analytical data with the aim to identify the ore sources from which these metals originated the interpretation of lead isotope and chemical data of 71 swedish bronze age metals is based on the direct comparisons between the lead isotope data and geochemistry of ore deposits that are known to have produced copper in the bronze age the presented interpretations of chemical and lead isotope analyses of swedish metals dated to the nordic bronze age are surprising and bring some information not known from previous work apart from a steady supply of copper from the alpine ores in the north tyrol the main sources of copper seem to be ores from the iberian peninsula and sardinia thus from the results presented here a new complex picture emerges of possible connectivities and flows in the bronze age between scandinavia and europe