imaging near surface heterogeneities by natural migration of backscattered surface waves s u m m a r y we present a migration method that does not require a velocity model to migrate backscattered surface waves to their projected locations on the surface this migration method denoted as natural migration uses recorded green s functions along the surface instead of simulated green s functions the key assumptions are that the scattering bodies are within the depth interrogated by the surface waves and the green s functions are recorded with dense receiver sampling along the free surface this natural migration takes into account all orders of multiples mode conversions and non linear effects of surface waves in the data the natural imaging formulae are derived for both active source and ambient noise data and computer simulations show that natural migration can effectively image near surface heterogeneities with typical ambient noise sources and geophone distributions

what s in a name the aurignacian in romania abstract the key position held by romania s territory for the available scenarios regarding the expansion of the upper paleolithic cultural package in europe has been recently reinforced by the finds of the oldest european homo sapiens sapiens remains in the oase cave southwestern romania however in spite of its paradigmatic association to the first anatomically modern humans in europe the aurignacian in romania remained inadequately known and rarely referred to in the european literature the poor descriptions of the aurignacian called lithic industries and their unusually young numerical chronology or geochronological estimations explain this caution a brief evaluation of the available information regarding these issues is proposed based on a comparatively restricted definition of the aurignacian variability as acknowledged in the recent european literature e g numerical chronology large retouched blades bladelet production from carinated forms bone industry the present approach dismisses many postulates widely held in romanian literature the local origin the wide occurrence and the late survival of the aurignacian however given the lack of numerical dates and the fragmentary state of most archaeological collections the precise timing of its emergence and the details of its regional evolution require further research

frost and soils implications for paleosols paleoclimates and stratigraphy abstract frost is a pedogenetic agent this paper describes the use of frost features in soil for paleoclimatic and stratigraphic interpretation it is possible to differentiate periods of frost activity from those of temperate pedogenesis by macroscopic and microscopic criteria and to distinguish between soils with pre syn and epigenetic frost effects an experimental approach is necessary to determine initial frost effects because they are usually difficult to observe at natural active sites work with ecologists also clarifies the evolution of frost affected soils under climatic and vegetational constraints vegetation has important effects on the thermal and hydraulic regimes of soils and on erosion susceptibility the recognition of fossil cryosoils often allows the reconstruction of sequences of paleoclimatic events in periods or environments with little or no micropaleontological evidence the interrelations between frost and other pedogenetic processes allow a better understanding of climatic evolution and deterioration throughout the neogene and especially during the quaternary and the holocene most of the inherited frost features in european soils are younger than 480 ka bp the differentiation between frost and tectonic perturbations is very important for calculation of soil erosional budgets

three dimensional simulations of ground motions in the san bernardino valley california for hypothetical earthquakes on the san andreas fault three dimensional finite difference simulations of elastic waves in the san bernardino valley were performed for two hypothetical earthquakes on the san andreas fault a point source with moment magnitude m5 and an extended rupture with m6 5 a method is presented for incorporating a source with arbitrary focal mechanism in the grid synthetics from the 3 d simulations are compared with those derived from 2 d vertical cross section and 1 d flat layered models the synthetic seismograms from the 3 d and 2 d simulations exhibit large surface waves produced by conversion of incident s waves at the edge of the basin seismograms from the flat layered model do not contain these converted surface waves and underestimate the duration of shaking the seismograms from the 3 d simulations have larger amplitude coda than do the seismograms from the 2 d case because of the presence of off azimuth surface wave arrivals in the 3 d simulations that are not included in the 2 d simulations snapshots of the wavefield of the 3 d simulation show that these off azimuth arrivals represent surface waves reflected from the edges of the basin the anelastic attenuation of the sediments is a key parameter controlling the overall duration of motion some of the coda energy at rock sites near the basin edges represents leakage of surface wave energy out of the basin for the m6 5 earthquake simulation the largest ground velocities occur where surface waves reflected from the edge of the basin interfere constructively with the trapped waves that follow the direct s wave maps of maximum ground velocity are produced for two directions of rupture propagation the largest velocities occur in localized portions of the basin the location of the largest velocities changes with the rupture propagation direction contours of maximum shaking are also dependent on asperity positions and radiation pattern

tracking textural mineralogical and geochemical signatures in soils developed from basalt derived materials covered with loess sediments sw poland abstract this study investigates the scale of inheritance of signatures typical of loess and basalt derived substrates in soils having both components present as parent material due to past periglacial processes based on field description particle size distribution mineralogy heavy minerals and clay minerals as well as geochemistry we track the signal of both materials local basalt derived and loess derived estimate the maximum thickness of loess mantles and mixed zones having both loess and basaltic components and note the presence or absence of basal layers without allochtonous additions the results show that geochemistry and heavy minerals are the most reliable proxies for a verification of aeolian silt contributions and to define individual layers in complex soil parent materials soil formation in the studied landscape depends on the type of slope sediments typical fine grained weathering of basalt without input from aeolian silt would promote rather vertic development however in thick loess deposits as well as in thin silt textured materials superimposed on clay loam beds clay illuviation dominates development of argic horizons however results in decreasing permeability promoting water stagnation and enhanced degradation processes in clay rich subsoil instead of luvisols stagnosols and retisols developed in the study regions basaltic block covers mixed with loess host cambic horizons based on our findings it seems that at the edge of thin loess deposits no soils exist that developed exclusively from basaltic parent materials

soils with fragipans in the usa abstract fragipans are dense subsurface soil layers that severely restrict water flow and root penetration they are considered a pedogenic horizon but their exact genesis is not well understood in soil taxonomy 2010 a fragipan is defined as a layer that is at least 15 cm thick contains a coarse structure and is reversibly cemented we examined 362 pedons with fragipans in the natural resources conservation service nrcs ssurgo database and 36 case studies in the usa from the literature soils with fragipans are classified primarily at the great group but also at the subgroup level fragipans occur in four orders alfisols ultisols inceptisols spodosols 10 suborders 23 great groups and 57 subgroups from the nrcs database fragipan soils have silty or loamy particle size classes 95 of total soil series an udic or aquic soil moisture regime 98 a mesic soil temperature regime 60 and a mixed mineralogy class 75 of total soil series although they occur in 28 states in the usa the most extensive areas of soils with fragipans occur in the southern mississippi river valley and the central and southern appalachian mountains soils with fragipans are most common east of the 97 w meridian and in forested areas where precipitation exceeds evaporation these soils are derived from silt rich materials especially loess and low lime tills 61 of total soil series and occur primarily in lower moderately well drained topographic positions the genesis of fragipans involves wetting and drying possibly influenced by the presence of lithologic discontinuities which lead to hydro consolidation that causes close packing of grains and reduces porosity although silica may bind clays and fe oxides and bridge skeletal grains this property is not recognized in the definition of the fragipan in the conterminous usa soil mapping units containing soils with fragipans occupy 970 000 km 2 12 of the land area

the aurignacian way of life contextualizing early modern human adaptation in the carpathian basin abstract the culture and dispersal of early modern humans are top priorities of many research agendas while the debate primarily centers on genetics dispersal trajectories and points of earliest presence the context climate landscape demography culture of the colonizing process is usually considered in a coarse grained manner or even ignored to understand the context of human dispersal and to decipher relevant push and pull factors requires the consideration of multiple environmental proxies and the research on different geographic scales in this paper we present the late quaternary carpathian basin as a specific context area of early modern human dispersal into europe the multitude of early upper paleolithic sites in this region suggests that it was part of a major dispersal corridor along the danube and its catchment area some 40 000 years ago the aurignacian land use model describes the interaction of early modern humans with their environment one important parameter is the specific distribution of archaeological sites that exemplifies their boundedness to specific eco zones to reconstruct the latter paleo environmental proxies and archaeological data are examined together in regional vector models and in a gis based landscape archaeology approach in the final section we present the carpathian basin as an idiosyncratic habitat that mirrors the dynamics and complexity of early modern human adaptation

strong sh to love wave scattering off the southern california continental borderland seismic scattering is commonly observed and results from wave propagation in heterogeneous medium yet deterministic characterization of scatterers associated with lateral heterogeneities remains challenging in this study we analyze broadband waveforms recorded by the southern california seismic network and observe strongly scattered love waves following the arrival of teleseismic sh wave these scattered love waves travel approximately in the same azimuthal direction as the incident sh wave at a dominant period of 10 s but at an apparent velocity of 3 6 km s as compared to the 11 km s for the sh wave back projection suggests that this strong scattering is associated with pronounced bathymetric relief in the southern california continental borderland in particular the patton escarpment finite difference simulations using a simplified 2 d bathymetric and crustal model are able to predict the arrival times and amplitudes of major scatterers the modeling suggests a relatively low shear wave velocity in the continental borderland

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

dating of post glacial landforms in the central howgills little is known of holocene landform development in upland britain this paper describes a site at middle langdale in the howgill fells of cumbria where large but now stabilized and inactive gullies cut through periglacial material at the base of the gullies large debris cones have buried earlier alluvial sediments on the valley floor on these sediments and buried by the debris cones is a well developed organic soil from which two 14c dates have been obtained in an attempt to estimate the age range of the soil these dates range from 2580 55 years bp for the fine particulate fraction from the base of the organic horizon to 940 95 years bp for fossil rootlets from the uppermost organic layer immediately below the overlying debris cones the pollen evidence suggests that the valley floor site was initially dominated by alder carr and later by a juncus marsh with birch alder and hazel nearby the pollen from the surrounding upland area suggests woodland on the valley sides dominated by oak and elm that was later replaced by a more open environment rich in heath species and in which disturbed ground species were present the magnetic evidence indicates a stable local environment during soil formation but shows a sudden inwash of unweathered debris at the top of the buried soil the evidence suggests that the valley floor was geomorphologically stable throughout the period of soil formation although there was a local change in valley floor vegetation and a reduction of woodland cover on the valley sides at sometime during the period the evidence then points to major geomorphological changes a wave of soil erosion gully development and debris cone deposition perhaps following the scandinavian introduction of sheep farming in the tenth century a d

scattering of teleseismic p waves by the japan trench a significant effect of reverberation in the seawater column abstract we detected a scattered wave train in data from the high sensitivity seismograph network in japan hi net following the arrival of the near vertically incident p wave generated by the 2009 earthquake mw 7 8 off the south island of new zealand the scattered wave train represented predominantly vertical ground motion at a period of 20 to 50 s and with an apparent velocity of 3 5 km s it propagated cylindrically westward through the kanto area of central japan array analysis showed that the scattered wave train developed beneath the pacific ocean near the boso triple junction southeast of the kanto area a 3d finite difference simulation of seismic wave propagation using a high resolution model incorporating subsurface structure topography and bathymetry revealed that the strong scattered waves that were generated along the japan trench and propagated normal to the trench axis represented multiple reverberations of seismic waves between the seafloor and the pacific plate boundary in addition strong reverberation of acoustic waves in the seawater column above the boso triple junction causes elongated scattered waves which reasonably explains our observations

holocene alluvial fan and terrace formation in the bowland fells northwest england in the bowland fells lancashire northwest england in the headwater valleys of the hodder river system is a suite of holocene fluvial landforms debris cones and alluvial fans at tributary junctions and river terraces along the main valleys post date late pleistocene forms and pre date the modern valley floor alluvial forms eight 14c dates from wood samples incorporated within the terrace and fan deposits have allowed two main phases of holocene erosion to be identified with debris cone fan deposition taking place after c 5400 bp but before c 1900 bp and again at c 900 bp some of the fans and cones are complex with deposits attributable to both phases others are simple and attributable only to the later phase in the headwaters an upper terrace at c 5400 bp pre dates the cones and a lower terrace is contemporaneous with the first debris cone phase lower downvalley the youngest of three terraces date from c 5000 bp or earlier indicating that the sequence is less complex downstream

ubiquity of anomalous fading in k feldspars and the measurement and correction for it in optical dating anomalous fading rates were measured in k feldspars separated from 49 sediment samples mainly from north america the intensity of the optically stimulated luminescence was found to decrease linea

effects of topography on seismic wave propagation an example from northern taiwan topography influences ground motion and in general increases the amplitude of shaking at mountain tops and ridges whereas valleys have reduced ground motions as is observed from data recorded during and after real earthquakes and from numerical simulations however recent publications have focused mainly on the implications for ground motion in the mountainous regions themselves whereas the impact on surrounding low lying areas has received less attention here we develop a new spectral element mesh implementation to accommodate realistic topography as well as the complex shape of the taipei sedimentary basin which is located close to the central mountain range in northern taiwan spectral element numerical simulations indicate that high resolution topography can change peak ground velocity pgv values in mountainous areas by 50 compared to a half space response we further demonstrate that large scale topography can affect the propagation of seismic waves in nearby areas for example if a shallow earthquake occurs in the i lan region of taiwan the central mountain range will significantly scatter the surface waves and will in turn reduce the amplitude of ground motion in the taipei basin however as the hypocenter moves deeper topography scatters body waves which subsequently propagate as surface waves into the basin these waves continue to interact with the basin and the surrounding mountains finally resulting in complex amplification patterns in taipei city with an overall pgv increase of more than 50 for realistic subduction zone earthquake scenarios off the northeast coast of taiwan the effects of topography on ground motion in both the mountains and the taipei basin vary and depend on the rupture process the complex interactions that can occur between mountains and surrounding areas especially sedimentary basins illustrate the fact that topography should be taken into account when assessing seismic hazard

investigating the last glacial gravettian site sagvar lyukas hill hungary and its paleoenvironmental and geochronological context using a multi proxy approach abstract gravettian population during the last glacial maximum lgm was sparse in europe this is generally related to harsh environmental conditions here we report of geoarcheological investigations physical chemical and biological data of the sagvar site in the hungarian part of the carpathian basin in southeastern europe geochronological control is given by luminescence dating which places loess accumulation between 20 6 1 4 ka and 17 7 1 2 ka this study demonstrates that human occupation at sagvar did not occur during a rather mild climatic phase but during a typical cold lgm climate of the two cultural layers discussed at the section the upper one can be clearly distinguished in the section by the physical proxy data while the lower one is observed only in some proxies similarly previous archeological investigations describe a higher tool density in the upper layer the mollusk composition indicates dry climate for both occupation phases but the paleoecology of the lower occupation phase suggests also the presence of mosaic spots of wet tundra which allowed for increased weathering processes in the sediment these are preserved as indications for weak pedogenesis in the physical and chemical proxy data although a disturbance of human occupation in the signal cannot be excluded this study demonstrates the advantages of integrating proxy data of different disciplines

comparison of quartz osl protocols using lateglacial and holocene dune sands from brandenburg germany abstract we present the results obtained using various different protocols in the quartz optically stimulated luminescence dating of a late glacial and holocene aeolian dune sequence near eberswalde north of berlin germany the allerod finow palaeosol and the laacher see tephra layer serve as chronostratigraphic markers and further independent age control is provided by eight 14 c ages the application of the single aliquot regenerative dose protocol using blue light stimulation and the multiple aliquot regenerative dose and additive dose protocols using broad band blue and green light stimulation are discussed a comparison of radionuclide analyses using high resolution gamma spectrometry and neutron activation analysis is also presented it is concluded that the two dosimetry methods give indistinguishable results although the gamma spectrometry data are more precise in contrast the single aliquot regenerative dose protocol is between 2 and 10 times more precise than the multiple aliquot protocols and systematic differences in performance are also observed the uncertainties in the dosimetry calculations are the largest contributor to the overall age uncertainties the accuracy of the resulting ages is considered very satisfactory when tested against the independent age controls over the entire age range from the present to 15 ka

rayleigh wave multipathing along the west coast of north america we have created a movie of surface ground motion for the 3 november 2002 denali fault earthquake based on spectral element simulations using crustal model crust2 0 mantle model s20rts topography and bathymetry model etopo5 and a finite fault slip model the movie features two anomalous wave packets that travel along the west coast of the north american plate following off great circle paths these wave packets are rayleigh waves with dominant periods around 20 sec which are also found in seismograms recorded by the southern cali fornia seismic network one of these packets is the direct surface wave whose group arrival time changes laterally as dictated by the shape of the oregon coast the other packet is a surface wave reflected by a lateral interface underneath the rocky moun tains a linear reflector parallel to the canadian coast offsetting it by a few hundred kilometers can explain its arrival time but the offsetting distance derived from the synthetic seismograms puts the reflector 350 km northeast of the result obtained from the data indicating a need to update the crustal and mantle models in this area online material animation of normalized simulated vertical displacement for the 2002 denali earthquake

studies of the seismic coda using an earthquake cluster as a deeply buried seismograph array loosely speaking the principle of green s function reciprocity means that the source and receiver positions in a seismic experiment can be exchanged without affecting the observed seismograms consequently the seismograms observed at a single observation location o and caused by a cluster of microearthquakes at locations ei are identical to the time series that would be measured by an array of stress meters emplaced at positions ei recording waves generated by a source acting at o by applying array analysis techniques like slant stacking and frequency wave number analysis to these seismograms we can determine the directions and velocities of the component waves as they travel in the earthquake focal region rather than at the surface we have developed a computationally rapid plane wave decomposition which we have applied to single station recordings of aftershocks of the 1984 morgan hill california earthquake the analysis is applied to data from three seismic stations having considerably different site geologies one is a relatively hard rock station situated on franciscan metamorphics one is within the calaveras fault zone and one is on semiconsolidated sand and gravels we define the early coda to be the part of the coda initiating immediately after the direct s wave and ending at twice the s wave lapse time the character of the s wave and early coda varies from being impulsive at the first station to highly reverberative at the last we examine waves in sequential time windows starting at the s wave and continuing through the early part of the coda at all seismic stations the early coda is dominated by a persistent signal that must be caused by multiple scattering probably within 2 km of each seismic station despite clear station to station differences in the character of the early coda coda q values measured in the late coda greater than twice the s lapse time agree well among stations implying that the mechanisms causing the varying behavior of the early coda do not control the coda decay rate at the stations we have considered coda q values measured on horizontal components of motion agree within a factor of 2 with those measured on vertical components we have not been able to determine the composition of the late coda because of a low signal to noise ratio our analysis technique however is quite appropriate for such a task

anomalous surface waves associated with deep earthquakes generated at an ocean ridge summary broad band seismograms observed at regional distances from deep earthquakes display large amplitude rayleigh and love waves with a predominant period of about 20 s although deep earthquakes in laterally homogeneous structures do not generate such surface waves since the propagation direction of the surface waves inferred from particle motion is approximately radial and the group velocity of the surface waves observed at each station is similar it can be assumed that the surface waves have travelled close to the great circle paths back projection allows us to determine the region in which these surface waves are generated manyof the zones from which the surface waves appear to originate are located close to the norfolk ridge where crustal structure has strong lateral heterogeneity this suggests that the surface waves are generated by the interaction of body waves from the deep earthquakes with this strongly heterogeneous crustal structure in order to investigate the eiect of such heterogeneity in crustal structure on seismic wave elds we have modelled the p sv wave eld using a pseudospectral method the results show that surface waves such as those observed can be generated by ridge structures and indicate that sedimentary layer thickness plays a very important role we suggest that such unexpected surface waves from deep earthquakes may prove useful for delineating heterogeneity in shallow structure

a scattered wave image of subduction beneath the transverse ranges over 5600 short period recordings of teleseismic events were used to create deterministic maps of p wave scatterers in the upper mantle beneath southern california between depths of 50 and 200 kilometers the southern flank of the slab subducting beneath the transverse ranges is marked by strong scattering the marked scattering indicates that the edge of the slab is a sharp thermal boundary such a boundary could be produced by slab shearing or small scale convection in the surrounding mantle the northern limb of the slab is not a strong scatterer consistent with thicker lithosphere north of the transverse ranges

luminescence dating of the stratzing loess profile austria testing the potential of an elevated temperature post ir irsl protocol abstract feldspar infrared stimulated luminescence irsl signals saturate at 2000 gy i e 500 700 ka assuming a dose rate of 3 4 gy ka typical for loess and it is therefore theoretically possible to date middle pleistocene loess however the accuracy of age estimates is hampered by anomalous fading which leads to significant age underestimation fading corrections have been proposed but these corrections are reliant on inherent assumptions and in any case are inapplicable at large doses as the growth curve approaches saturation recent studies have identified a post ir irsl signal that shows less fading and is thus less dependent on accurate fading corrections this study builds upon these investigations and applies a post ir irsl sar dating protocol to polymineral fine grain samples of the loess palaeosol sequence in stratzing lower austria after a preheat at 320 c 60 s and an ir bleach at 50 c 200 s irsl was measured at 290 c for 200 s the same set of conditions were used to measure the response to a test dose recycling ratios recuperation and dose recovery tests show that this protocol is suitable for the loess under investigation although finite residual doses of up to 20 gy are observed for the oldest samples the natural signal is in or close to saturation indicating that fading is negligible in nature this observation is inconsistent with the measured laboratory fading rates of 1 1 5 decade and needs further investigation

digital image analysis of outcropping sediments comparison to photospectrometric data from quaternary loess deposits at şanoviţa romania and achenheim france abstract the possibility to use colour data as extracted from two selected loess paleosol sequences is discussed here colour data are a fast and inexpensive method of proxy data generation we compare the outcome from analysing outcrop images taken by digital cameras in the field and spectral colour data as determined under controlled laboratory conditions by nature differences can be expected due to variations in illumination moisture and sample preparation outcrop inclination may be an issue for photographs correction for this is possible when marks can be used for rectification in both cases the data extracted from the images match the visual impression of the photos well and are useful for obtaining a more quantitative measure for field observations smoothness as measured by autocorrelation is high for an image from achenheim france where an image with a width of ca 1 1 m and a depth of 1 6 m was analysed data from a narrower image part from anovi a romania are noisier in both cases a significant correlation between data extracted by digital image analysis and laboratory measurements could be established suggesting that image analysis is a useful tool where outcrop and light conditions allow good photographs with similar illumination especially where high resolution proxy data is required

danube loess stratigraphy towards a pan european loess stratigraphic model abstract the danube river drainage basin is the second largest river catchment in europe and contains a significant and extensive region of thick loess deposits that preserve a record of a wide variety of recent and past environments indeed the danube river and tributaries may themselves be responsible for the transportation of large volumes of silt that ultimately drive loess formation in the middle and lower reaches of this large catchment however this vast loess province lacks a unified stratigraphic scheme european loess research started in the late 17th century in the danube basin with the work of count luigi ferdinand marsigli since that time numerous investigations provided the basis for the pioneering stratigraphic framework proposed initially by kukla 1970 1977 in his correlations of loess with deep sea sediments loess palaeosol sequences in the middle and lower reaches of the danube river basin were a key part of this framework and contain some of the longest and most complete continental climate records in europe covering more than the last million years however the very size of the danube loess belt and the large number of countries it covers presents a major limiting factor in developing a unified approach that enables continental scale analysis of the deposits local loess palaeosol stratigraphic schemes have been defined separately in different countries and the difficulties in correlating such schemes which often change significantly with advances in age dating have limited the number of basin wide studies a unified basin wide stratigraphic model would greatly alleviate these difficulties and facilitate research into the wider significance of these loess records therefore we review the existing stratigraphic schemes and define a new danube basin wide loess stratigraphy based around a synthetic type section of the mosorin and stari slankamen sites in serbia we present a detailed comparison with the sedimentological and palaeoclimatic records preserved in sediments of the chinese loess plateau with the oxygen isotope records from deep sea sediments and with classic european pleistocene stratigraphic subdivisions the hierarchy of danubian stratigraphic units is determined by climatically controlled environmental shifts in a similar way to the chinese loess stratigraphic scheme a new unified danube loess stratigraphic model has a number of advantages including preventing confusion resulting from the use of multiple national schemes a more transparent basis and the potential to set pleistocene palaeoenvironmental changes recorded in the danube catchment area into a global context the use of a very simple labelling system based on the well established chinese loess scheme facilitates interpretation of palaeoenvironmental information reported from the danube basin loess sites in a wider more accessible context that can be readily correlated world wide this stratigraphic approach also provides for the first time an appropriate framework for the development of an integrated pan european and potentially pan eurasian loess stratigraphic scheme

genesis of loess like sediments and soils at the foothills of the banat mountains romania examples from the paleolithic sites românesti and cosava abstract the paleolithic sites rom nesti and cosava situated at the foothills of the banat mountains in romania provide an important testament of life of the first european modern humans homo sapiens sapiens during middle pleniglacial even though these sites have been extensively excavated little is known about the site formation of related loess like sediments and soils first luminescence data at the two investigated sections confirm sediments from the penultimate glacial period to the holocene assigning the levels of findings is difficult because the sediments are close to the surface and are overprinted by recent soil development albeluvisols influenced by stagnic features are the typical surface soils in the study area and on comparable morphological positions in the region laboratory analysis has revealed that this soil has a complex genesis from hydrolysis weathering which is connected with the development of a fragic soil horizon overprinting the major find horizons at both sites by using sedimentological and geochemical methods in combination this study aims to reconstruct sedimentary evolution and soil processes at the sites as well as to evaluate the state of preservation and the actual content of the archeological contexts initial results indicate hints for a forest step and higher vegetation during mis 3 at the foothills of the carpathian mountains in the western plain of romania these natural factors offer a local attractiveness of the region which could be the most important reason for the occurrence of first anatomically modern humans our investigations lend a better understanding of the paleoenvironment as well as a first age control of paleolithic levels for the region

origin of reversible cementation and brittleness of the fragipan horizon in albeluvisols of the carpathian foothills poland abstract fragipan horizon is a natural subsurface soil layer exhibiting higher bulk density and lower porosity in comparison with the overlying horizons significantly restricting infiltration of water and root penetration in contrast to hard and cemented horizons e g duripan clods of the fragipan horizon btx slake or fracture immediately when placed in water the most interesting issue concerning genesis and properties of the fragipan horizon is its reversible cementation i e very hard consistence in dry state and brittle consistence in moist state the main objective of the present study was to explain and improve the understanding of the specific consistence of the fragipan horizon in moderately humid climate on the example of albeluvisols of the carpathian foothills in poland basing on mineral and chemical composition of bridges linking coarse soil material quantitative x ray diffraction shows that the studied fragipan horizon contains high concentration of swelling clay minerals soil material from the fragipan horizon exhibits numerous clay and iron clay coatings and clay infillings indicating translocation of colloidal clay and iron oxides from overlying horizons in addition bridges between coarse grains of the soil material occur the fragipan cementing material is composed mainly of sio2 al2o3 and fe2o3 with lower concentration of k2o mgo cao and na2o the chemical composition of bridges within the pan is similar to that of clay coatings and clay infillings suggesting that clay minerals are major bonding agents and are responsible for brittleness and more friable consistence of the pan in the moist state additionally free iron aluminium and silica may play some role in specific cementation of the investigated fragipan horizon but these elements are not main bonding agents

diversity and peculiarities of soil formation in eolian landscapes insights from the mineral magnetic records abstract magnetic properties of loess paleosol sequences are widely utilized as sensitive easily obtained and reliable proxy archives of past climate change in continental settings however soil formation in aeolian landscapes may occur under different and changing conditions of dust sedimentation which will affect the growth and development of the pedogenic magnetic component this phenomenon is explored in our study by analyzing depth variations of the following magnetic characteristics frequency dependent magnetic susceptibility anhysteretic magnetic susceptibility and the ratio between anhysteretic susceptibility and isothermal remanent magnetization acquired in a 100 mt back field arm irm 100 mt along three loess paleosol profiles from ne bulgaria a conceptual model for the time evolution of the grain size of the pedogenic magnetic fraction with soil depth is proposed which is build upon the mechanism of soil formation accretional or in stable land surfaces or a combination of the two another magnetic ratio isothermal remanence acquired in a 300 mt back field divided by low field magnetic susceptibility irm 300 mt is utilized as a proxy for the changes in the ratio of silt to clay fractions indicative of changes in dust sedimentation regimes during glacial interglacial transitions according to the proposed conceptual model verified by the magnetic signature of three holocene soils from ne bulgaria discrimination between accretional soils and soils developed without dust additions during soil forming period can be done accretional soils are characterized by parallel changes in grain size sensitive magnetic proxies soils developed at stable landscape conditions show gradation of the depths at which maximum enhancement of various proxies occurs with deepest occurrence of the maximum in fd followed by depth of maximum arm and arm irm 100 mt another implication of the new conceptual model is that the mean coercivity of the pedogenic component of accretional soils will be higher than that of soils developed without eolian input at equal temperature conditions because of the soils thermal gradient and different depths at which pedogenic minerals form in the two settings the results revealed that the holocene soils so has developed under different soil forming conditions than paleosols from the same sites

three climatic cycles recorded in a loess palaeosol sequence at semlac romania implications for dust accumulation in south eastern europe recent inve stigations of the semlac loess section in the south eastern carpathian basin which is situated at an undercut slope position on the right bank of the mures river in its lower reaches banat region western romanian are presented and discussed dating back to marine isotope stage mis 10 the more than 10 m thick loess sequence includes four fossil soil complexes developed in homogenous and relatively fine silty loess because of the good preservation of the sediment semlac is regarded as a key section for the carpathian basin which offers possibilities to a improve the understanding of the type and composition loess homogeneity and pedogenic alteration of the lowland loess sequences in the carpathian basin also beyond the last interglacial palaoesol complex b to reconstruct the temporal evolution of the local loess palaoesol successions c gain better insight into the regional paleoenvironments of the last 300ka and d to compare the loess of the region to loess sequences in adjacent areas and to dust proxy data in the northern hemisphere an integrated age model based on correlation to reference records and luminescence dating is compiled applying this age model we compare climate proxy data from semlac to both global data and to data from the very southeast of the carpathian basin vojvodina serbia the obtained results provide new insight into the dust accumulation regime for the eastern carpathian basin and offer new palaeoenvironmental information for the region and are an important step towards establishing a catena from the thin loess like sediments of the banat foothills in the east towards the thicker and seemingly more complete loess sections of the south eastern and central carpathian basin disentangling grain size data from soil formation proxies is used to investigate patterns of non local dust patterns of non pedogenetic fine material are similar to grain size proxies from china and other parts of the northern hemisphere suggesting western and eastern eurasian loess to have at least partly similar mechanistic climatic origins c 2016 elsevier ltd all rights reserved

global synthetic seismograms using a 2 d finite difference method two dimensional 2 d finite difference fd synthetics which fill the gap between fast 1 d analytic synthetics and time consuming full 3 d synthetics in our ability to model seismograms have been used in many studies we address several issues involving 2 d fd methods in generating global synthetic seismograms these include 1 interfacing point source excitation for earthquakes with 2 d fd methods 2 out of plane spreading corrections and 3 reducing the spherical earth to the flattened models the first issue is tackled using two methods a transparent source box approach and a moment tensor excitation approach where each has its own advantages moreover our source box excitation does not have the late time drift problem that occurred in previous studies the out of plane geometric spreading correction is accounted for by estimating the ray parameter and applying a post simulation filter to 2 d synthetics finally parameters of the earth flattening transformation are discussed and validated the effectiveness of this method is demonstrated by comparing our synthetics with frequency wavenumber summation normal mode and 3 d spectral element synthetics

particle size scales and classification of sediment types based on particle size distributions review and recommended procedures this paper provides a review of different particle size scales size class terminology and particle size distribution textural classification schemes which are widely used in sedimentology geomorphology soil science aquatic ecology and civil engineering it is concluded that a revised system of size class nomenclature based on the udden 1898 and wentworth 1922 schemes provides the most logical and consistent framework for use with sediments and a wide range of other particulate materials a refined scheme is proposed which has five first order size classes boulder gravel sand silt and clay each of which has five second order subdivisions with limits defined at one phi intervals the scheme is simple and intuitively easy to understand the paper also provides a review of previous schemes that have been proposed to describe and classify sediments on the basis of the proportions of gravel sand and mud or sand silt and clay using trigons also termed ternary diagrams many of these schemes do not have a logical basis and provide limited or uneven resolution new gravel sand and mud and sand silt and clay classification systems are proposed that are both more logical and provide greater discriminatory power than previous schemes they are therefore more suitable for use in environmental and forensic investigations a new microsoft excel program freely available to download from http www kpal co uk allows rapid classification of sediments based on the proportions of gravel sand and mud and sand silt and clay proportions and graphical comparison of the data for different sample groups

preliminary reassessment of the aurignacian in banat south western romania abstract despite its richness the romanian paleolithic record has remained for decades relatively poorly known to the broader scientific community the situation swiftly changed after the find at oase cave which brought the romanian paleoanthropological and archeological record into intensive focus spurring several international research projects devoted to the regional early upper paleolithic the present paper provides the first summary of recent research undertaken in the neighboring area of oase the romanian banat particularly focused on the aurignacian open air occupation at cosava a detailed attribute analysis of both old and recently excavated aurignacian collections from cosava supplemented by a comparative overview of the allegedly similar industry at rom nesti dumbr vi a is presented an initial chronological assessment of the banat aurignacian by means of several osl samples from rom nesti is also proposed the results of the lithic analysis much like the new chronological estimations in excess of 30 ka bp confirm the early assignment of the banat assemblages to the krems type aurignacian but also dismiss the unusually young chronology initially attributed to these settlements while several features including the constant presence of krems dufour tools point strongly to an archaic stage of the aurignacian technocomplex protoaurignacian aurignacian 0 other elements carinated forms twisted bladelets and aurignacian blades recall more classical features conventionally associated to the aurignacian i no coherent chrono stadial trend or functional requirements can explain these mixed features in the banat industries with the data at hand their presence nevertheless points to the internal variability of these early aurignacian occurrences

patterns of development of lavaka madagascar s unusual gullies lavaka madagascar s abundant gullies show a complex pattern of development fourteen independent measures of size and shape in 93 lavaka were investigated by principal components analysis and discriminant function analysis typical lavaka start either as wounds and raw patches on mid hillside that develop step like head scarps or as toe slopes collapsed by seepage slumping or undercutting they become deep raw vertical sided teardrop to heart shaped gashes that may be deepest and broadest uphill as the walls retreat slump and become overgrown lavaka become longer broader gentler and partly filled concavities they can grow to reach from the valley floor to the hill crest or even beyond the crest before healing over unless excessive erosion creates tors and inselbergs they heal over and end up as unremarkable hillside reentrants and side valleys

high resolution paleoclimatic proxy data from the mis3 2 transition recorded in northeastern hungarian loess abstract the bodrogkeresztur loess paleosol sequence in northeastern hungary was investigated to improve our understanding of the paleoenvironmental conditions at the foothills of the carpathians and their impact on the gravettian population the main part of the section is comprised of eolian deposits that enable the reconstruction of the paleoenvironmental conditions this study comprises grain size geochemical color and rock magnetic analysis as well as luminescence and radiocarbon dating the chronological data place this section from later mis 3 until present but also suggest erosion of the sediment in the late mis 2 and the early holocene moreover generally more humid conditions during late mis3 and early mis2 are observed in comparison to other regions in the carpathian basin main dust source was most likely the tisza floodplain and the material was probably transported to the site from a northeastern wind direction increased weathering led to the formation of a well developed mis3 paleosol the loess exhibits elevated values of frequency dependent magnetic susceptibility that highlight the relatively mild conditions during loess formation nevertheless two loess layers with high sand abundance in the profile indicate colder and dryer conditions with increased eolian dynamics during short periods within mis2 finally the bodrogkeresztur section highlights the unique microclimatic conditions at the foothill areas of the carpathian basin which may have offered a favorable environment for the gravettian population

late pleistocene loess palaeosol sequences in the vojvodina region north serbia late pleistocene loess palaeosol sequences are widespread in the vojvodina region with thicknesses reaching a maximum of about 20 m our investigations include more than 40 of these loess sections geochronology of the last glacial loess palaeosol sequences based on lumines cence dating and amino acid racemisation provides correlations between upper pleistocene loess palaeosol sediments in vojvodina and comparable deposits at other european localities sedimentary logs of magnetic susceptibility grain size measurements and carbonate content combined with malacological evidence indicate two main relatively cold and arid phases during the last glacial period related to intensive accumulation of loess units l1l1 and l1l2 as well as many brief episodes of dry and windy climatic conditions suggesting a possible relationship with cold events recorded in the north atlantic region generally late pleistocene climate in the region was dry and relatively warm compared with glacial period sites in central europe and was characterised by sharp differences between glacial and interglacial modes new data and interpretations presented in this study emphasise the significance of loess palaeosol sequences in vojvodina for the reconstruction of the temporal and spatial evolution of late pleistocene palaeoclimate in this part of europe copyright 2007 john wiley sons ltd

crusted microtopography on badland slopes in southeast spain summary badland slopes developed in soft miocene marine marls of the guadix baza depression of southeast spain have four crust types developed on them the bare crusted surfaces are confined to slopes with southerly aspects the north facing slopes are sparsely vegetated and these crusts are generally absent the crusts and the weathered mantle on which they occur have been tested for soil ec aggregate stability and investigated in thin section the distribution of crust types in a representative badland gully has been mapped one of the crust types the pediment crust is a depositional feature found on low angled pediments flanking the steep gully side slopes the other three crust types domed tower and pinnacle represent a sequence of increasing age and increasing stability associated with progressive colonisation by the blue green algae microcoleus vaginatus and scytonema and the lichen dermatocarpon lachneum while this is accompanied by a progressive reduction in soil ec the evidence suggests that the algae and lichen play an important role in stabilising the soil surface the development sequence of these crust types is outlined

lithospheric structure across the california continental borderland from receiver functions due to its complex history of deformation the california continental borderland provides an interesting geological setting for studying how the oceanic and continental lithosphere responds to deformation we map variations in present day lithospheric structure across the region using ps and sp receiver functions at permanent stations of the southern california seismic network as well as ocean bottom seismometer obs data gathered by the asthenospheric and lithospheric broadband architecture from the california offshore region experiment albacore which enhances coverage of the borderland and provides first direct constraints on the structure of the pacific plate west of the patton escarpment noisiness of obs data makes strict handpicking and bandpass filtering necessary in order to obtain interpretable receiver functions using h and common conversion point stacking we find pronounced lithospheric differences across structural blocks which we interpret as indicating that the outer borderland has been translated with little to no internal deformation while the inner borderland underwent significant lithospheric thinning most likely related to accommodating the 90 clockwise rotation of the western transverse range block west of the patton escarpment we find that the transition to typical oceanic crustal thickness takes place over a lateral distance of 50 km we detect an oceanic seismic lithosphere asthenosphere transition at 58 km depth west of the patton escarpment consistent with only weak age dependence of the depth to the seismic lithosphere asthenosphere transition sp common conversion point stacks confirm wholesale lithospheric thinning of the inner borderland and suggest the presence of a slab fragment beneath the outer borderland

shallow basin structure and attenuation are key to predicting long shaking duration in los angeles basin ground motions in the los angeles basin during large earthquakes are modulated by earthquake ruptures path effects into the basin basin effects and local site response we analyzed the direct effect of shallow basin structures on shaking duration at a period of 2 10 s in the los angeles region through modeling small magnitude shallow and deep earthquake pairs the source depth modulates the basin response particularly the shaking duration and these features are a function of path effect and not site condition three dimensional simulations using the cvm s4 26 m01 velocity model show good fitting to the initial portion of the waveforms at periods of 5 s and longer but fail to predict the long shaking duration during shallow events especially at periods less than 5 s simulations using cvm h do not match the timing of the initial arrivals as well as cvm s4 26 m01 and the strong late arrivals in the cvm h simulation travel with an apparent velocity slower than observed a higher quality factor than traditionally assumed may produce synthetics with longer durations but is unable to accurately match the amplitude and phase beamforming analysis using dense array data further reveals the long duration surface waves have the same back azimuth as the direct arrivals and are generated at the basin edges while the later coda waves are scattered from off azimuth directions potentially due to strong sharp boundaries offshore improving the description of these shallow basin structures and attenuation model will enhance our capability to predict long period ground motions in basins

fragipan horizon degradation and bleached tongues formation in albeluvisols of the carpathian foothills poland a fragipan horizon is defined as a natural dense subsurface soil horizon which restricts the infiltration of water and the penetration of roots most fragipans show evidence of degradation which manifests itself in the formation of bleached tongues along vertical cracks despite the fact that fragipans have been extensively studied since the 1940s the problem of their genesis degradation and vertical tongues formation remains obscured the main aim of the present study was to explain the genesis of bleached tongues in fragipan horizon using the example of albeluvisols from the carpathian foothills in poland undisturbed soil material was subjected to detailed micromorphological analysis using optical microscopy bulk soil material and soil clay fractions were analyzed quantitatively using x ray diffraction basing on the obtained results it is concluded that the formation of the vertical cracks is likely to be a result of seasonal drying which promotes the opening of cracks the prevalence of swelling clay minerals within illuvial horizons promotes periodic swelling and shrinking due to moisture changes once vertical cracks are formed the next phase of fragipan degradation i e bleached tongues formation takes place tongues formation is most likely caused by the eluviation microerosion of weathering products eluviation is indicated by a lower concentration of clay minerals and iron oxides in material from vertical tongues when compared with material from prismatic clods and btx horizon in the studied soils the formation of tongues due to the infilling of vertical cracks with material from an upper eluvial horizon is also likely but only in the upper parts of the cracks

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

geophysical evidence for miocene extension and mafic magmatic addition in the california continental borderland the california continental borderland is a key region for understanding the effect on crustal structure of tectonic processes associated with the initiation and elongation of the san andreas transform system because the borderland lies near the point where the pacific farallon spreading system first encountered the north american plate margin whereas the central and northern california margins have been extensively investigated by geophysical surveys in recent years the crustal structure of the borderland particularly the outer borderland has received relatively little attention this paper presents three gravity models that stretch from the pacific ocean floor to shore they provide new evidence that the crust of the entire california continental borderland has been extended and infiltrated by mafic melt since early miocene time the gravity models were constructed from interpretations of nearly 750 km of seismic reflection data seismic refraction studies and geologic maps thus minimizing the nonuniqueness of the method the evidence for extension in the models is that the crust of the accretionary complex and forearc basin that make up the borderland is only 22 km thick 35 thinner than comparable crustal sections in central and northern california extension could well have been accommodated by eastward flow of accretionary complex material during middle miocene formation of a metamorphic core complex in the inner borderland the gravity models also show that the accretionary complex is 100 200 kg m 3 more dense than commonly observed to the north this density difference may result from influx of basaltic melts due to mantle upwelling at the rivera triple junction and beneath the highly extended inner borderland the borderland models permit the occurrence of a discrete mafic layer that forms the base of the crust as is seen along the central and northern california coast but do not require such a layer9s presence anywhere except immediately inland of the shelf slope break

localized water reverberation phases and its impact on backprojection images coherent radiators imaged by back projections bp are commonly interpreted as part of the rupture process nevertheless artifacts introduced by structure related phases are rarely discriminated from the rupture process in this study we use a calibration event to discriminate between rupture and structure effects we re examine the waveforms and bp images of the 2012 mw 7 2 indian ocean earthquake and a calibration event mw 6 2 the p wave codas of both events present similar shape with characteristic period of approximately 10 s which are back projected as coherent radiators near the trench s wave bp doesn t image energy radiation near the trench we interpret those coda waves as localized water reverberation phases excited near the trench we perform a 2d waveform modeling using realistic bathymetry model and find that the steep near trench bathymetry traps the acoustic water waves forming localized reverberation phases these waves can be imaged as coherent near trench radiators with similar features as that in the observations we present a set of methodologies to discriminate between the rupture and propagation effects in bp images which can serve as a criterion of subevent identification

millennial scale climate oscillations recorded in the lower danube loess over the last glacial period abstract in this study we provide a correlative age model for last glacial loess at the rasova valea cu pietre site in the lower danube region based on the correlation of palaeoenvironmental proxies to independently dated palaeoclimate archives luminescence dating and independent age control provided by the geochemically confirmed presence of the campanian ignimbrite ci tephra the ci tephra originating in the phlegrean fields of southern italy has been dated elsewhere by 40ar 39ar to 39 40 ka bp and is frequently found in the lower danube loess as such the ci tephra represents a valuable temporal and stratigraphic maker across loess deposits in the region our age model facilitates high resolution correlation of palaeoenvironmental features observed at rasova to palaeoclimate archives in greenland and the black sea mediterranean area we observe semi cyclic behaviour of the frequency dependent magnetic susceptibility throughout the profile which we ascribe to millennial scale climate variability also observed elsewhere in the black sea region this is the first study to clearly identify millennial scale climate variability over the holocene and last glacial in the lower danube loess proxy variability in the holocene indicates continuous aeolian sedimentation through this epoch

seismic determination of elastic anisotropy and mantle flow when deformed many rocks develop anisotropic elastic properties on many seismic records a long period 100 to 250 seconds quasi love wave with elliptical polarization arrives slightly after the love wave but before the rayleigh wave mantle anisotropy is sufficient to explain these observations qualitatively as long as the fast axis of symmetry is approximately horizontal quasi love observations for several propagation paths near pacific ocean subduction zones are consistent with either flow variations in the mantle within or beneath subducting plates or variations in the direction of fossil spreading in older parts of the pacific plate

process interactions temporal scales and the development of hillslope gully systems howgill fells northwest england abstract hillslope gully development is often controlled by interactions between multiple processes rather than by individual processes such interactions may have both spatial and temporal characteristics a twenty year monitoring program of hillslope gullying in the howgill fells northwest england has identified the roles of both on slope interactions and slope stream coupling interactions which can be related to several temporal scales on slope interactions are primarily seasonal whereas those related to coupling produce a cyclicity over timescales of up to several years over the longer term decades or more progressive changes in gully morphology modify the nature of both sets of interactions and through negative feedback mechanisms may ultimately lead to gully stabilisation gully development is controlled by the rates of headwall recession and the basal incision stabilisation behaviour after basal stabilisation vegetation encroachment onto the eroding slopes takes place faster than headwall retreat resulting in a finite age and limiting size for gully development a simple model based on the current rates of development adequately describes the morphology of modern gullies but is inappropriate when applied to an older generation of stabilised gullies this suggests that there have been changes in sediment generation and removal rates during the late holocene

first chronometric dates tl and osl for the aurignacian open air site of românesti dumbrăviţa i romania abstract currently absolute dates for the emergence of the early upper paleolithic and the timing of the earliest dispersal of anatomically modern humans amh into europe are sparse this is especially true for regions adjoining the eastern mediterranean and central europe with its dense clusters of sites along the austrian and german danube valley this article makes a first step toward filling this gap and for the first time presents absolute ages for the open air site of rom nesti dumbr vi a i banat sw romania located close to the oase cave where some of the oldest amh fossils were found a set of heated artefacts recently excavated from the aurignacian layer gh3 was dated by thermoluminescence tl and gives early chronometric dates for this technocomplex in romania the luminescence behavior of artefact samples required the use of different multiple and single aliquot measurement protocols to obtain reliable age information in addition analyses of glow curves and the performance during regenerative dose measurements allowed us to distinguish two types of samples since one group is characterized by poor dose reproducibility only samples showing reliable luminescence behavior were considered for final age interpretations as a result we could determine that the last heating of artefacts from gh3 happened most likely between 39 ka single aliquot age estimate and 45 ka multiple aliquot age estimate ago with a weighted average age of the gh3 finds of 40 6 1 5 ka including all data these dates were confirmed by osl dating of sediments of the find layer such an early age fits well to technological and typological features which place the dated lithic assemblage at the very beginning of the development of the aurignacian technocomplex usually seen as a proxy for the earliest wide spread presence of amh in europe

full 3 d tomography for crustal structure in southern california based on the scattering integral and the adjoint wavefield methods we have successfully applied full 3 d tomography f3dt based on a combination of the scattering integral method si f3dt and the adjoint wavefield method aw f3dt to iteratively improve a 3 d starting model the southern california earthquake center scec community velocity model version 4 0 cvm s4 in f3dt the sensitivity frechet kernels are computed using numerical solutions of the 3 d elastodynamic equation and the nonlinearity of the structural inversion problem is accounted for through an iterative tomographic navigation process more than half a million misfit measurements made on about 38 000 earthquake seismograms and 12 000 ambient noise correlagrams have been assimilated into our inversion after 26 f3dt iterations synthetic seismograms computed using our latest model cvm s4 26 show substantially better fit to observed seismograms at frequencies below 0 2 hz than those computed using our 3 d starting model cvm s4 and the other scec cvm cvm h11 9 which was improved through 16 iterations of aw f3dt cvm s4 26 has revealed strong crustal heterogeneities throughout southern california some of which are completely missing in cvm s4 and cvm h11 9 but exist in models obtained from previous crustal scale 2 d active source refraction tomography models at shallow depths our model shows strong correlation with sedimentary basins and reveals velocity contrasts across major mapped strike slip and dip slip faults at middle to lower crustal depths structural features in our model may provide new insights into regional tectonics when combined with physics based seismic hazard analysis tools we expect our model to provide more accurate estimates of seismic hazards in southern california

geophysical evidence for the evolution of the california inner continental borderland as a metamorphic core complex we use new seismic and gravity data collected during the 1994 los angeles region seismic experiment larse to discuss the origin of the california inner continental borderland icb as an extended terrain possibly in a metamorphic core complex mode the data provide detailed crustal structure of the borderland and its transition to mainland southern california using tomographic inversion as well as traditional forward ray tracing to model the wide angle seismic data we find little or no sediments low 6 6 km s p wave velocity extending down to the crust mantle boundary and a thin crust 19 to 23 km thick coincident multichannel seismic reflection data show a reflective lower crust under catalina ridge contrary to other parts of coastal california we do not find evidence for an underplated fossil oceanic layer at the base of the crust coincident gravity data suggest an abrupt increase in crustal thickness under the shelf edge which represents the transition to the western transverse ranges on the shelf the palos verdes fault merges downward into a landward dipping surface which separates basement from low velocity sediments but interpretation of this surface as a detachment fault is inconclusive the seismic velocity structure is interpreted to represent catalina schist rocks extending from top to bottom of the crust this interpretation is compatible with a model for the origin of the icb as an autochthonous formerly hot highly extended region that was filled with the exhumed metamorphic rocks the basin and ridge topography and the protracted volcanism probably represent continued extension as a wide rift until 13 m y ago subduction of the young and hot monterey and arguello microplates under the continental borderland followed by rotation and translation of the western transverse ranges may have provided the necessary thermomechanical conditions for this extension and crustal inflow

book reviewseismic migration imaging of acoustic energy by wavefield extrapolation a theoretical aspects a j berkhout developments in solid earth geophysics 14a elsevier amsterdam 1982 2nd revised

early upper paleolithic surface collections from loess like sediments in the northern carpathian basin abstract the way in which modern humans first entered europe has been a recent focus of upper paleolithic research a leading theory posits that the danube served as a conduit for migration from southeastern into central and western europe however a challenge to this has been the scarcity of early upper paleolithic sites along the middle danube carpathian basin though several sites with early upper paleolithic features szeletian aurignacian are known from surface prospections few have been archeologically investigated in detail here our aim is to elucidate this long standing deficiency by evaluating two unknown and three known sites from the northern carpathian basin in hungary and slovakia through a series of keyhole excavations the objectives were to see if in situ stratified material still existed and to characterize the sites archeological assemblages and sedimentological contexts to do this field observations supplemented by granulometry were employed to determine if the surrounding sedimentary matrix was eolian loess and or if it had been mixed with underlying older deposits the results indicate that the lithics represent early upper paleolithic assemblages that experienced post depositional mixing however two sites se a i nagyrede 1 showed more nuanced site formation processes and may contain in situ artifacts warranting further exploration these studies highlight the importance of including sedimentological research into archeological investigations because the paucity of sites may not simply mean a lack of human occupation but can indicate a dynamic geomorphological evolution of the pleistocene landscape that may have erased past traces of human settlements through insufficient sedimentation the results provide new insights into the early upper paleolithic settlement and the sedimentary dynamics of the carpathian basin ultimately leading to a greater understanding of the early modern human settlement patterns in europe