identification of neolithic to modern erosion sedimentation phases using geochemical approach in a loess covered sub catchment of south moravia czech republic abstract a colluvial soil with a 380 cm deep humus enriched horizon was studied in a loess region of south moravia czech republic which is characterized by a strong soil material re deposition distribution of soil properties within the colluvial soil profile was used for distinguishing the different sedimentation phases and understanding colluvial soil formation the colluvial profile is stratified into different horizons distinguishable by a specific distribution of basic soil properties soil organic carbon content carbonate content or soil reaction in the profile low organic carbon content 0 6 0 8 and increased carbonate content up to 8 in the upper 260 cm indicates a rapid change of the soil cover and significant admixture of loess parent material in the sediment an abrupt increase of organic carbon content 2 and no carbonates between 300 and 380 cm is evidence of a buried chernozem at this depth antropogenically induced substances such as pesticide residues or increased nutrient content connected to agricultural practices enables the detection of sedimentation periods the peak ddt content up to 0 04 mg kg at the depth of 50 150 cm clearly delineates the material sedimented in the 1950s 1970s and material sedimented in earlier or later stages the same trend can be traced in phosphorus and potassium content given by intensive use of fertilizers at a given time period the potential use of lead and cadmium as another indicator of anthropogenic influence at some stage of soil sedimentation was not proven due to their low concentration in the colluvial profile three phases of soil erosion and sedimentation were distinguished each reflecting different land use and intensity of agriculture the highest amount of soil material 2 m deposited in the colluvial profile can be attributed to the last and shortest erosional phase corresponding to intensive agriculture and massive land consolidation in the last 70 years

systematic analysis of crustal anisotropy along the karadere duzce branch of the north anatolian fault s u m m a r y we perform a systematic analysis of crustal anisotropy along and around the karadere duzce branch of the north anatolian fault naf which ruptured during the 1999 mw 7 4 izmit and mw 7 1 duzce earthquakes a method consisting of an iterative grid search for the best shear wave splitting parameters in sliding time windows is applied to 22 000 measurements recorded in the 6 month period after the izmit main shock based on objective criteria 6600 measurements are assigned high quality and used for further detailed analysis most stations near the rupture zone have fast polarization directions that are parallel to and change with the nearby fault strike the average delay times for ray paths that propagate along the rupture zone are larger than for the other paths these results suggest the existence of an approximately 1 km broad zone around the karadere duzce branch with fault parallel cracks or shear fabric however some fault zone fz stations record bimodal or scattered polarization directions while stations near large structural complexities e g branching and offsets show average fast polarization directions that are almost perpendicular to the local fault strike the average fast polarization directions from ray paths that propagate inside the almacik block south of the karadere duzce branch are neither parallel to the local fault strike nor to the expected regional maximum compressive stress direction the large overall spatial variations of the results imply that multiple structures and mechanisms contribute to the observed crustal anisotropy in our study area most stations do not exhibit a clear dependency of shear wave splitting delay time with increasing depth and hypocentral distance indicating that the anisotropy is confined primarily to the top 3 4 km of the crust using the observed average delay time at fz stations and assumed propagation distance of 3 5 km we estimate the apparent crack density in the damaged shallow fz rock to be approximately 7 per cent

influence of pedon history and washing nature on luminescence dating of holocene colluvium on the example of research on the polish loess areas abstract although colluvium is a valuable record of past human impact there is a lack of a precise method of age determination the luminescence method could be used but the basic difficulty is partial bleaching of quartz grains in this study colluviums from southern poland were investigated using the osl method all examples for this study are colluviums deposited on holocene fossil soils in dry valleys in all cases the area of research has been very well recognized in terms of archaeological significance the youngest 50 year old colluviums were also studied using the 137 cs method the obtained luminescence results are in stratigraphic order and in good agreement with archaeological data and 14 c dating the dated sediment samples are usually well bleached this is not due to transportation on the slope but rather from mixing by ploughing or bioturbation osl dating results together with distributions may therefore be helpful in determining the origin of colluvium this is not possible by examination of macroscopic lithogenetic characteristics as the diagnostic sedimentary structures of colluvium were destroyed by postsedimentation soil processes the results confirmed that soil erosion started in the neolithic

human induced soil erosion and gully system development in the late holocene and future perspectives on landscape evolution the myjava hill land slovakia in humid climate zones like central europe past soil erosion and gullying are strongly connected with agricultural expansion and extreme soil erosion events often play an important role in land abandonment this paper provides a case study to demonstrate the interaction between land use soil erosion floodplain development and land use changes in a 0 order catchment in the babikovce catchment myjava hill land situated in western slovakia sedimentological pedological geoarchaeological and historical data indicate two main periods of intensive hillslope erosion and gullying since the high middle ages in particular a few extreme precipitation events or rapid snowmelts caused intensive runoff events and gullying on cleared land the formation of the gully system and fan deposits in the babikovce catchment and other areas also forced the occurrence of intensive muddy floods and caused floodplain aggradation and meander changes along rivers in the myjava hill land as a result the development of the dense network of permanent gullies in the myjava hill land can be associated with the transformation of woodland into farmland and later land abandonment today the area is highly truncated by soil erosion and very difficult to farm

passive monitoring of anisotropy change associated with the parkfield 2004 earthquake 1 we investigate temporal variations in the polarization of surface waves determined using ambient seismic noise cross correlations between station pairs at the time of the mw 6 0 parkfield earthquake of september 28 2004 we use data recorded by the high resolution seismic network s 3 component seismometers located along the san andreas fault our results show strong variations in azimuthal surface wave polarizations for the paths containing station varb one of the closest stations to the san andreas fault synchronous with the parkfield earthquake concerning the other station pair only smooth temporal variations of are observed two principal contributions to these changes in are identified and separated they are 1 slow and weak variations due to seasonal changes in the incident direction of seismic noise and 2 strong and rapid rotations synchronous with the parkfield earthquake for paths containing station varb strong shifts in are interpreted in terms of changes in crack induced anisotropy due to the co seismic rotation of the stress field because these changes are only observed on paths containing station varb the anisotropic layer responsible for the changes is most likely localized around varb in the shallow crust these results suggest that the polarization of surface waves may be very sensitive to changes in the orientations of distributed cracks and that implementation of our technique on a routine basis may prove useful for monitoring stress changes deep within seismogenic zones

geological and industrial implications of extensive dilatancy anisotropy extensive dilatancy anisotropy is the hypothesized distribution of stress aligned fluid filled microcracks pervading most rocks in the earth s crust the geometry of the cracks and the aligning stress field can be monitored by analysing the waveforms of shear waves propagating through the rockmass the ability to estimate some of the parameters of the crack and stress geometry by analysing shear wave particle displacements has widespread implications

seasonality in particle motion of microseisms summary microseisms are a continuous source of seismic signal which mainly consist of rayleigh waves but are known to contain some other types of seismic waves we developed a simple processing procedure for single station three component seismic data which allows us to select rayleigh wave dominated portions application of this procedure to data from southern california led us to confirm that excitation of the secondary peak microseisms the predominant energy at about 0 15 hz occurs in coastal regions the source directions viewed at each station do not change very much throughout the year we also discovered that the ratio of the horizontal to vertical amplitudes in rayleigh waves termed h z in this paper is shown to have seasonal variations the h z estimates typically reach their maximum in winter and their minimum in summer seasonal variations are observed at most stations but peak to peak amplitudes of seasonal variations vary greatly from station to station ranging between 0 and 40 per cent two hypotheses were examined to explain this phenomenon the first hypothesis is that it is caused by seasonal changes in seismic velocities in a layer between the surface and the groundwater level the second hypothesis is that it is caused by seasonal changes in relative excitation of higher modes compared to dominant fundamental mode rayleigh waves the first hypothesis is not likely because predicted amplitudes of seasonal variations in h z are too small to explain observed variations the second hypothesis seems quite plausible if source regions move seasonally among regions with different ocean depths the technique developed in this paper however is not sufficient to answer this question conclusively

75 plus years of anisotropy in exploration and reservoir seismics a historical review of concepts and methods the idea that the propagation of elastic waves can be anisotropic i e that the velocity may depend on the direction is about 175 years old the first steps are connected with the top scientists of that time people such as cauchy fresnel green and kelvin for most of the 19th century anisotropic wave propagation was studied mainly by mathematical physicists and the only applications were in crystal optics and crystal elasticity during these years important steps in the formal description of the subject were made at the turn of the 20th century rudzki stressed the significance of seismic anisotropy he studied many of its aspects but his ideas were not applied research in seismic anisotropy became stagnant after his death in 1916 beginning about 1950 the significance of seismic anisotropy for exploration seismics was studied mainly in connection with thinly layered media and the resulting transverse isotropy very soon it became clear that the effect of layer induced anisotropy on data ac

array estimators and the use of microseisms for reconnaissance of sedimentary basins a natural field seismic technique is possible to attain by observing microseisms with a suitably designed array and by digitally processing the data to obtain estimates of the phase velocities of rayleigh waves wavelengths of interest in detecting depth to the basement of sedimentary basins are in the range 2 to 20 km and correspond to wave periods from 1 to 7 s an array of five or seven seismometers deployed as an expanding cross configuration simplifies field procedures and is adequate for phase velocity measurements of rayleigh waves in the required wavelength range provided high resolution frequency wavenumber spectral analysis is used this analysis can be implemented on a minicomputer in the field results obtained from observation in a sedimentary basin of known structure show predominantly fundamental mode rayleigh wave propagation the scatter of velocity estimates is small enough to allow inversion by curve matching and depth to the basement can be computed to an accuracy of 30 percent w

the san andreas fault revisited through seismic noise and surface wave tomography 1 we present here surface wave tomography results for the san andreas fault in the parkfield area california usa that were extracted from microseismic noise in the 0 15 hz to 0 35 hz frequency band using passive seismic correlation techniques using directive noise incoming from the pacific ocean passive seismic noise tomography was performed using three component sensors from a dense seismic network a rotation algorithm was applied to the nine component noise correlation tensor that optimally forced each station pair to re align in the noise direction a necessary condition to extract unbiased travel times from passive seismic processing after the rotation was performed an optimal surface wave tensor is obtained from which love waves were extracted for tomography inversion dispersion curves were then inverted to obtain a three dimensional shear velocity map showing vertical geological structures and a 1 3 km wide low seismic velocity dip which are in agreement with previous tomography studies in the same area

holocene evolution of closed depressions and its relation to landscape dynamics in the loess areas of poland past pleistocene topography of the loess uplands is rich in local sinks closed depressions cds influencing sediment fluxes soil sediment sequences from cds constituting geoarchives where lands

near surface seismic anisotropy attenuation and dispersion in the aftershock region of the 1999 chi chi earthquake summary seismograms from local aftershocks of the 1999 chi chi taiwan earthquake recorded at a 200 m deep downhole station chy of the taiwan central weather bureau seismic network cwbsn have clear direct upgoing shear waves and their surface reflected downgoing phases measurements of time difference between the direct and reflected phases of the fast and slow components of split shear waves show approximately 8 per cent velocity anisotropy in the top 200 m of the crust the phase velocities extracted from the direct and reflected waveforms display clear evidence of attenuation related dispersion taking the dispersion and geometrical spreading factor into account we estimate the q value of the shear waves by fitting calculated results to the observed reflected waveforms the amplitude spectral density ratios between the direct and reflected phases are approximately linear within the frequency range 2 15 hz this allows us also to estimate the q value from the slope of the amplitude spectral ratio in db hz 1 i nthis range the estimated q values with both methods based on a set of similar waveforms and additional 156 high quality records are 61 68 for the fast components and 43 52 for the slow components the observed attenuation anisotropy may be similarly to velocity anisotropy a manifestation of microcracks alignment and their response to in situ stress strong attenuation anisotropy 23 30 per cent in this study along with attenuationrelated dispersion in the shallow crust can affect significantly the properties of shear waves and should be taken into account in studies employing surface and shallow borehole records of shear waveforms

some aspects of age assessment of holocene loess colluvium osl and 137cs dating of sediment from biala agricultural area south poland abstract at the end of the pleistocene in central eastern europe the accumulation of periglacial loess had already finished from the end of loess accumulation to the establishment of grass cover and forest succession in this area a phase of active modeling of the land surface by slope processes occurred before the beginning of the holocene this activity stopped and mollisol and alfisol formation started these soils are preserved beneath holocene colluvia until the neolithic age the area of loess formations in poland was uninhabited the extensive neolithic agriculture locally induced soil erosion causing slopewash on farmedslopes the scale of this process and establishing the age of the successive stages of the prehistoric soil erosion in loess deposits in poland is a key problem in the investigations of the human environment relationship in prehistory chronostratigraphy of the preserved holocene colluvia is very helpful in the solution of these problems optical osl dating was applied in chronostratigraphical analyses due to expected partial bleaching during sediment transport a single aliquot regenerative dose protocol sar was applied insufficient bleaching during transport on the slope is expected to be a serious problem for luminescence dating of loess colluvia and causes overestimation of the osl age quartz from the study site was suitable for age determination by sar the youngest 50 year old colluvia were also studied using the 137cs method the reliability of the obtained results is discussed in this paper as well as the influence of environmental processes and type of the applied methods on chronological assignments the precise age determination of loess colluvia is important for study of the human impact on the environment the results of osl dating show that soil erosion started in the neolithic with three phases of soil erosion neolithic middle ages and modern

passive seismic imaging with directive ambient noise application to surface waves and the san andreas fault in parkfield ca summary this study deals with surface waves extracted from microseismic noise in the 0 1 0 2 hz frequency band with passive seismic correlation techniques for directive noise we explore the concept of passive seismic noise tomography performed on three component sensors from a dense seismic network from the nine component correlation tensor a rotation algorithm is introduced that forces each station pair to re align in the noise direction a necessary condition to extract unbiased traveltime from passive seismic processing after rotation is performed the new correlation tensor exhibits a surface wave tensor from which rayleigh and love waves can be separately extracted for tomography inversion methodological aspects are presented and illustrated with group speed maps for rayleigh and love waves and ellipticity measurements made on the san andreas fault in the parkfield area california usa

analysis of three component ambient vibration array measurements summary both synthetic and observed ambient vibration array data are analysed using high resolution beam forming in addition to a classical analysis of the vertical component this paper presents results derived from processing horizontal components we analyse phase velocities of fundamental and higher mode rayleigh and love waves and particle motions ellipticity retrieved from h v spectral ratios a combined inversion with a genetic algorithm and a strategy for selecting possible model parameters allow us to define structural models explaining the data the results from synthetic data for simple models with one or two layers of sediments suggest that in most cases the number of layers has to be reduced to a few sediment strata to find the original structure generally reducing the number of soft sediment layers in the inversion process with genetic algorithms leads to a class of models that are less smooth they have a stronger impedance contrast between sediments and bedrock combining love and rayleigh wave dispersion curves with the ellipticity of the fundamental mode rayleigh waves has some advantages scatter is reduced when compared to using structural models obtained only from rayleigh wave phase velocity curves by adding information from love waves some structures can be excluded another possibility for constraining inversion results is to include supplementary geological or borehole information analysing radial components also can provide segments of rayleigh wave dispersion curves for modes not seen on the vertical component finally using ellipticity information allows us to confine the total depth of the soft sediments for real sites considerable variability in the measured phase velocity curves is observed this comes from lateral changes in the structure or seismic sources within the array constraining the inversion by combining love and rayleigh wave information can help reduce such problems frequency bands in which the rayleigh wave dispersion curves show considerable scatter are often better resolved by love waves information from the horizontal component can be used to correctly assign the mode number to the different phase velocity curve segments especially when two modes seem to merge at osculation points such merging of modes is usually observed for rayleigh waves and thus can be partly solved if additional information from the love waves and the horizontal component of rayleigh waves is considered whenever a site presents a velocity inversion below the top layer love wave data clearly helps to better constrain the solution

systematic analysis of shear wave splitting in the aftershock zone of the 1999 chi chi taiwan earthquake shallow crustal anisotropy and lack of precursory variations we analyze shear wave splitting sws in a high quality waveform data set recorded at surface and downhole 0 2 km seismometers in a region around the 20 september 1999 m w 7 6 chi chi taiwan earthquake sequence the data set was generated by events in a 5 year period before during and after the mainshock the purpose is to investigate the depth extent of the crustal anisotropy and its possible temporal evolution in relation to the occurrence of large earthquakes results from downhole records show a stable polarization direction of the fast shear wave that matches well the local global positioning system gps velocity field a slightly different polarization direction of the fast shear wave is obtained from surface data this suggests a possible anisotropy change between the top 0 2 km structure and the deeper section of the crust measured time delays below the downhole station have an average value of 0 16 sec without systematic changes for sources from about 8 km to 20 km in depth estimates of time delays in the top 0 2 km of the crust based on shear waves reflected from the free surface give a constant 0 04 sec a likely depth distribution inferred from these two types of measurements and an s velocity model indicates that the crustal anisotropy in the region is dominated by the top 2 to 3 km the measured polarization directions and time delays give essentially constant values over the 2 7 year premainshock and 2 3 year postmainshock periods in the region adjacent to the chi chi rupture and within 10 km from the epicentral region of its two large m 6 0 aftershocks analysis of sws in waveforms produced by earthquake multiplets confirms further the lack of precursory temporal variations of crustal anisotropy in the immediate neighborhood of the chi chi earthquake sequence the results raise doubts on the general usefulness of sws measurements for earthquake forecasting an apparent coseismic increase in anisotropy time delay of approximately 10 is observed for depths 0 2 km however this value is clearly affected by spatial changes associated with different event locations before and after the chi chi mainshock

deposits of neolithic water soil erosion in the loess region of the malopolska upland s poland a case study of the settlement micro region in bronocice abstract in the well known settlement micro region of the malopolska upland known for extensive studies into the neolithic agricultural anthropopressure the authors have re examined three selected holocene soil sediment sequences derived from soil erosion by water the macroscopic features of both colluvium and proluvium deposits of gully erosion from an area of very strong neolithic anthropopressure in the nidzica river basin have been described and analyses of the basic characteristics of sediments and fossil soils as well as micro morphological analyses performed 40 samples were dated with the sar osl method the results of 14c and osl dating point to the stabilization of loess slopes in the holocene until the intensification of agricultural activity in the funnel beaker culture trb neolith about 3900 cal bc apart from the neolithic colluvium and proluvium only colluvia accumulated during the last millennium were found the presence of bronze age colluvium remains a possibility osl dating confirmed a strong link between the increase in prehistoric farming activity and the growing intensity of holocene water erosion it also revealed the presence of colluvial sequences of erosion gaps with the geologic record obliterated by later pedogenic processes and impossible to identify on the basis of classical macroscopic and micromorphological analyses the study has also shown that the osl method is an important tool in chronostratigraphy of the holocene colluvia as long as it is supported by deep paleo geographical analysis of the entire basin and knowledge of colonization history this method is not suitable for dating gully erosion sediments thus the age of the oldest neolithic gully erosion deposits in bronocice was determined on the basis of dating of the overlaying colluvia

shear wave anisotropy in the crust around the san andreas fault near parkfield spatial and temporal analysis summary we systematically analysed shear wave splitting sws for seismic data observed at a temporary array and two permanent networks around the san andreas fault saf observatory at depth the purpose was to investigate the spatial distribution of crustal shear wave anisotropy around the saf in this segment and its temporal behaviour in relation to the occurrence of the 2004 parkfield m 6 0 earthquake the dense coverage of the networks the accurate locations of earthquakes and the high resolution velocity model provide a unique opportunity to investigate anisotropy in detail around the saf zone the results show that the primary fast polarization directions pds in the region including the saf zone and the northeast side of the fault are nw se nearly parallel or subparallel to the saf strike some measurements on the southwest side of the fault are oriented to the nne ssw direction approximately parallel to the direction of local maximum horizontal compressive stress there are also a few areas in which the observed fast pds do not fit into this general pattern the strong spatial variations in both the measured fast pds and time delays reveal the extreme complexity of shear wave anisotropy in the area the top 2 3 km of the crust appears to contribute the most to the observed time delays however substantial anisotropy could extend to as deep as 7 8 km in the region the average time delay in the region is about 0 06 s we also analysed temporal patterns of sws parameters in a nearly 4 yr period around the 2004 parkfield main shock based on similar events the results show that there are no appreciable precursory coseismic or post seismic temporal changes of sws in a region near the rupture of an m 6 0 earthquake about 15 km away from its epicentre

luminescence dating of hillslope deposits a review abstract luminescence dating determines the last exposure to light of quartz and feldspar mineral grains and thus the time a sediment was laid down prerequisite is that the sediment grains were sufficiently exposed to light prior to deposition for eolian deposits this seems a fair assumption although exceptions may well exist for other depositional environments light exposure prior to burial is often restricted in duration intensity and spectral composition and may result in an age overestimation recent developments now allow dating of sediments that were exposed to only little light prior to deposition the main developments are single aliquot techniques and statistical tests that allow extraction of valid age estimates even from deposits in which bleached and unbleached grains are mixed these developments in combination with the fact that the great majority of sediments near the earth s surface are not of eolian origin have resulted in the large interest in the luminescence dating of non eolian deposits here we review possibilities and challenges of luminescence dating of colluvial deposits we summarize techniques for the detection and handling of insufficiently bleached sediments a common condition in colluvial deposits we give an overview how luminescence dating has been applied on hillslope sediments for reconstructing landscape response to climate change to analyze past fault activity and unravel human induced soil erosion we discuss sampling strategies and give guidelines as to which techniques are best suited to establish luminescence chronologies for colluvium

three dimensional compressional wavespeed model earthquake relocations and focal mechanisms for the parkfield california region we present a new three dimensional 3d compressional wavespeed v p model for the parkfield region taking advantage of the recent seismicity associated with the 2003 san simeon and 2004 parkfield earthquake sequences to provide increased model resolution compared to the work of eberhart phillips and michael 1993 epm93 taking the epm93 3d model as our starting model we invert the arrival time data from about 2100 earthquakes and 250 shots recorded on both permanent network and temporary stations in a region 130 km northeast southwest by 120 km northwest southeast we include catalog picks and cross correlation and catalog differential times in the inversion using the double difference tomography method of zhang and thurber 2003 the principal v p features reported by epm93 and michelini and mcevilly 1991 are recovered but with locally improved resolution along the san andreas fault saf and near the active source profiles we image the previously identified strong wavespeed contrast faster on the southwest side across most of the length of the saf and we also improve the image of a high v p body on the northeast side of the fault reported by epm93 this narrow body is at about 5 to 12 km depth and extends approximately from the locked section of the saf to the town of parkfield the footwall of the thrust fault responsible for the 1983 coalinga earthquake is imaged as a northeast dipping high wavespeed body in between relatively low wavespeeds 5 km sec extend to as much as 10 km depth we use this model to derive absolute locations for about 16 000 earthquakes from 1966 to 2005 and high precision double difference locations for 9 000 earthquakes from 1984 to 2005 and also to determine focal mechanisms for 446 earthquakes these earthquake locations and mechanisms show that the seismogenic fault is a simple planar structure the aftershock sequence of the 2004 mainshock concentrates into the same structures defined by the pre 2004 seismicity confirming earlier observations waldhauser et al 2004 that the seismicity pattern at parkfield is long lived and persists through multiple cycles of mainshocks online material 3d v p model and earthquake relocations

application of osl dating and 137cs measurements to reconstruct the history of water erosion a case study of a holocene colluvium in świerklany south poland abstract slopes used agriculturally at medium latitudes in european loess areas are modelled mainly by washing processes the thickness of colluvium depends on the intensity of washing processes and the length of time of agricultural use and it ranges from tens of centimetres to several meters in extreme cases in southern poland anthropogenic deforestation of some slopes and consequently washing processes begun as early as 5 ka however in many places these processes began much later as a result colluvium accumulated at the foot of the slopes corresponds to different stages of the prehistoric and historical anthropopressure those specific stages of anthropogenic prehistoric erosion can be distinguished by dating methods dating may be used to establish the beginning of the prehistoric agricultural activity in a particular area and to determine the extent of areas used for agriculture in the past to study holocene colluvium the wierklany site was selected mainly due to an archeological rescue excavation associated with the construction of the highway in the vicinity of wierklany village for laboratory study four sample profiles were collected from key points of the study area two of them were located at the foot of slopes one at the eroded part of the slope and one in a former pond area on the extension of the one of the tested slopes beside this 10 cores were collected to measure 137cs activity concentration as a modern erosion tracer in the laboratory analyses of 137cs activity concentration grain size distribution and luminescence characteristics were done the quartz extracted from the collected colluvial sediment was suitable for age determination based on the osl sar protocol the osl results for the lower part of the profiles indicate that fossil soils developed about 10 ka younger results from overlying materials were used to infer a range of erosion and transport processes since deforestation associated with the establishment of wierklany village in the thirteenth century the most modern phase of landscape activation are described by the 137cs measurements because 137cs is present on the slope deposits to plough depth the soil layer which contains 137cs was dated by the osl method for a period of 25 75 years and the results obtained with both methods are in good agreement results of investigations of the colluvium in wierklany area clearly document good bleaching of osl signal for sediments derived from washing slope sediment

determination of shallow shear wave velocity profiles in the cologne germany area using ambient vibrations summary we have used both single station and array methods to determine shallow shear velocity site profiles in the vicinity of the city of cologne germany from ambient vibration records based on fk analysis we assume that fundamental mode rayleigh waves dominate the analysed wavefield in the frequency range of 0 7 2 2 hz according to this view a close relation exists between h v spectral ratios and the ellipticity of the contributing rayleigh waves the inversion of the shape of h v spectral ratios then provides quantitative information concerning the local shear wave velocity structure however based on tests with synthetic data believed to represent a typical situation in the lower rhine embayment dispersion curves were found to provide stronger constraints on the absolute values of the velocity depth model than the ellipticities the shape of the ellipticities was found to be subject to a strong trade off between the layer thickness and the average layer velocity we have made use of this observation by combining the inversion schemes for dispersion curves and ellipticities such that the velocity depth dependence is essentially constrained by the dispersion curves while the layer thickness is constrained by the ellipticities in order to test this method in practice we have used array recordings of ambient vibrations from three sites where the subsurface geology is fairly well known and geotechnical information is at least partially available in order to keep the parameter space as simple as possible we attempted to fit only a single layer over a half space model however owing to earlier studies from the region we assume a power law depth dependence for sediment velocities for all three sites investigated the inversion resulted in models for which the shear wave velocity within the sediment layer both in absolute value at the surface and in depth dependence are found to be remarkably similar to the results obtained by budny from downhole measurements this is strong support for the interpretation of h v spectral ratios as rayleigh wave ellipticities for all three sites the predicted sh wave site amplification factors at the fundamental frequency are of the order of 5 6 with a slightly smaller value south of cologne

near real time near surface 3d seismic velocity and uncertainty models by wavefield gradiometry and neural network inversion of ambient seismic noisegradiometric wave equation inversion