quaternary reactivation of a basement structure in the barreirinhas basin brazilian equatorial margin the pirapemas lineament is a remarkable 200 km long ne sw trending structure in the barreirinhas basin one of the several brazilian coastal basins this lineament splits the study area in two sectors of distinctive morphology drainage patterns and sedimentary covers terrain northward of the lineament presents a smooth topography with sub parallel to sub dendritic drainage patterns whereas a dissected plateau characterized by incised valleys and rectangular drainage pattern occurs southward suggesting a structural control by joints and faults geological field data crossed with thermal luminescence tl and optically stimulated luminescence osl dating revealed that the surface southward of the lineament consists mostly of miocene and late pleistocene sedimentary deposits represented by the barreiras formation and the post barreiras sediments respectively in contrast relatively younger sands mantle most of the northward terrain as indicated by well preserved paleodune deposits that grade into active aeolian dunes of the lencois maranhenses national park geomorphological and geological data analysis suggests that the northern sector is under the effect of subsidence proving that the pirapemas lineament is an active agent modeling the landscape in the region geophysical data gravity and seismic confirm that such a structural feature is the surface expression of an active deep seated basement fault

pore properties as indicators of breakdown mechanisms in experimentally weathered limestones the results are reported of four experimental weathering tests freeze thaw wetting and drying slake durability and salt weathering on five different types of limestone effective porosity mercury intrusion porosimetry and scanning electron microscopy were used to evaluate changes in pore properties while weight loss and fracture density were used to assess deterioration severity a primary aim was to observe modifications in porosity due to weathering and to draw inferences about the internal rock deterioration mechanisms taking place it is concluded that the five limestones not only show a wide range of resistance to weathering in general but considerable difference in resistance to particular weathering processes consequently when assessing durability it is essential to consider rock properties in the context of the weathering process to which the rock is subject the type of deterioration indicator used is also important in interpretation of durability a variety of pore modification mechanisms operate including changes in pore connectivity pore infilling and the introduction of additional void space there are indications that changes to the internal pore structure of rocks due to weathering may be a precursor to more substantial macrodeterioration copyright 2001 john wiley sons ltd

lithological anomalies in a relict coastal dune geophysical and paleoenvironmental markers 1 ground exposures of migration surfaces slipfaces of a relict holocene coastal dune along the southeastern baltic sea coast provide an ideal opportunity for establishing the causes of prominent reflections on geophysical profiles high amplitude reflections on high resolution ground penetrating radar gpr images correlate well with two major lithological anomalies 1 paleosols developed on dune slipfaces and 2 slipfaces consisting of heavy mineral concentrations hmcs paleosols serve as indicators of dune stability represent datable chronostratigraphic surfaces and help reconstruct dune paleo morphology hmcs have substantially higher magnetic susceptibility values than background quartz rich sands and where they are well developed can be also used for spatial correlation based on their occurrence at the study site these enriched horizons likely represent periods of increased wind activity storminess multiple hmcs upwind of paleosol p1 800 670 cal years bp likely reflect periods of intensified wind activity along the southeast baltic region during the medieval warm period

effective electrode array in mapping karst hazards in electrical resistivity tomography when conducting environmental and engineering investigations in karst terranes engineers and geologists often supplement exploratory borehole results with data gathered from surface geophysics to reduce the site characterization cost and establish the most useful locations for borings or samples when conducting resistivity investigations a frequently occurring problem is the need to determine which of the many existing electrode configurations will respond best to the material changes in karst features each array has its advantages and disadvantages in terms of depth of investigation sensitivity to horizontal or vertical variations and signal strength in the application presented in this paper numerical forward modeling was conducted of dipole dipole schlumberger and wenner arrays and they produced markedly different anomaly shapes for a conceptual model of the development of a cover collapse sinkhole the resolution of the three above mentioned arrays was further evaluated along a section of i 70 near frederick maryland where a sinkhole had occurred in the median of the highway the image from the dipole dipole array appeared to be better than those from the wenner and schlumerger arrays in displaying the sinkhole collapse area however they are all less effective than a mixed array in which apparent resistivities from all the three arrays are combined and processed together in the model because the mixed array requires a significant increase in data collection the dipole dipole array appears to be the most effective and less costly configuration in mapping karst hazards areas this conclusion was then confirmed by two case studies

seismic imaging of reservoir flow properties time lapse amplitude changes asymptotic methods provide an efficient means by which to infer reservoir flow properties such as permeability from time lapse seismic data a trajectory based methodology much like ray based methods for medical and seismic imaging is the basis for an iterative inversion of time lapse amplitude changes in this approach a single reservoir simulation is required for each iteration of the algorithm a comparison between purely numerical and the trajectory based sensitivities demonstrates their accuracy an application to a set of synthetic amplitude changes indicates that they can recover large scale reservoir permeability variations from time lapse data in an application of actual time lapse amplitude changes from the bay marchand field in the gulf of mexico we are able to reduce the misfit by 81 in twelve iterations the time lapse observations indicate lower permeabilities are required in the central portion of the reservoir

hydrostratigraphic analysis of the made site with full resolution gpr and direct push hydraulic profiling 1 f ull resolution 3d ground penetrating radar gpr data were combined with high resolution hydraulic conductivity k data from vertical direct push dp profiles to characterize a portion of the highly heterogeneous macro dispersion experiment made site this is an important first step to better understand the influence of aquifer heterogeneities on observed anomalous transport statistical evaluation of dp data indicates non normal distributions that have much higher similarity within each gpr facies than between facies the analysis of gpr and dp data provides high resolution estimates of the 3d geometry of hydrostratigraphic zones which can then be populated with stochastic k fields the lack of such estimates has been a significant limitation for testing and parameterizing a range of novel transport theories at sites where the traditional advection dispersion model has proven inadequate citation dogan m r l van dam g c bohling j j butler jr and d w hyndman 2011 hydrostratigraphic analysis of the made site with full resolution gpr and direct push hydraulic profiling geophys res lett 38 l06405 doi 10 1029 2010gl046439

geodetic imaging reservoir monitoring using satellite interferometry summary fluid fluxes within subsurface reservoirs give rise to surface displacements particularly over periods of a year or more observations of such deformation provide a powerful tool for mapping fluid migration within the earth providing new insights into reservoir dynamics in this paper we use interferometric synthetic aperture radar insar range changes to infer subsurface fluid volume strain at the coso geothermal field furthermore we conduct a complete model assessment using an iterative approach to compute model parameter resolution and covariance matrices the method is a generalization of a lanczos based technique which allows us to include fairly general regularization such as roughness penalties we find that we can resolve quite detailed lateral variations in volume strain both within the reservoir depth range 0 4 2 5 km and below the geothermal production zone 2 5 5 0 km the fractional volume change in all three layers of the model exceeds the estimated model parameter uncertainty by a factor of two or more in the reservoir depth interval 0 4 2 5 km the predominant volume change is associated with northerly and westerly oriented faults and their intersections however below the geothermal production zone proper the depth range 2 5 5 0 km there is the suggestion that both north and northeast trending faults may act as conduits for fluid flow

reservoir monitoring and characterization using satellite geodetic data interferometric synthetic aperture radar observations from the krechba field algeria deformation in the material overlying an active reservoir is used to monitor pressure change at depth a sequence of 11 field estimates allows us to construct a measure of diffusive traveltime throughout a reservoir the dense distribution of traveltime values means that we can construct an exactly linear inverse problem for reservoir flow properties application to interferometric synthetic aperture radar insar data gathered over a carbon dioxide c o2 injection site in algeria reveals pressure propagation along two northwest trending corridors an inversion of the traveltimes indicates the existence of two northwest trending high permeability zones the high permeability features trend in the same direction as the regional fault and fracture zones model parameter resolution estimates indicate the features are well resolved

integrated geophysical and geomorphological approach to investigate the snowmelt triggered landslide of bosco piccolo village basilicata southern italy abstract most of basilicata region in the southern italian apennines is characterized by landslides often developing in clayey marly formations many events have been triggered by extreme rainfall or snowmelt the most important happened on february march 2005 at bosco piccolo 5 km far from potenza this landslide developed subsequently to rapid snowmelt occurred during alternating short periods of high temperatures and intense and continuous snowfalls this complex landslide affected 4 ha of surface and reached a maximum depth of 20 m inducing damage and collapse of about 80 of the buildings in the village an integrated multidisciplinary approach has been adopted to study the landslide a multitemporal aerial photo interpretation and detailed geomorphological surveys have been carried out combined electrical resistivity tomography ert and self potential sp measurements have been performed and calibrated with boreholes stratigraphy such an integrated approach allowed us to partially reconstruct the geometry of the investigated body and to evaluate the effectiveness of drainage system planned for the area

4 d constrained depth conversion for reservoir compaction estimation application to ekofisk field ekofisk field in the norweigian sector of the north sea is a remarkable example of a strongly compacted chalk reservoir since the start of production in 1971 the water bottom has subsided by over 8 m as a result of reservoir compaction hermansen et al the field wide waterflood begun in 1989 was expected to halt pressure depletion and reservoir compaction after a few years of waterflooding ekofisk reservoir pressure began increasing but compaction and subsidence continued laboratory studies on chalk cores indicated that high porosity oil filled chalk compacts strongly when flushed with seawater these studies along with reservoir flow simulation and geomechanic modeling led to a model of a water weakening compaction sylte et al ongoing efforts deployed to monitor the reservoir compaction and seabed subsidence include twice a year compaction logging in a monitoring well daily gps measurements at the platforms and periodic bathymetry surveys nine surveys from 1970 to 1999

precise gps acoustic positioning of seafloor reference points for tectonic studies abstract global networks for crustal strain measurement provide important constraints for studies of tectonic plate motion and deformation to date crustal strain measurements have been possible only in terrestrial settings on continental plates and island sites within oceanic plates we report the development of technology for horizontal crustal motion determination at seafloor sites allowing oceanic plates to be monitored where islands are not available seafloor crustal monitoring is an important component of global strain measurement because about 70 of the earth s surface is covered by water and this region contains most of the tectonic plate boundaries and zones of crustal deformation using the global positioning system gps satellites and underwater acoustics we have established a geodetic reference site on the juan de fuca plate at 2 6 km depth approximately 150 km off the northwest coast of north america we measure the baselines between this site and two terrestrial gps stations on vancouver island british columbia the juan de fuca plate site is an appropriate setting to develop seafloor observation methods since it is a well studied area easily accessible from west coast canadian and united states ports determination of seafloor motion at this site addresses questions related to convergence between the juan de fuca and north american plates across the cascadia subduction zone at the juan de fuca seafloor geodetic reference site we installed precision acoustic transponders on the seafloor and measured ranges to them from a sound source at a surface platform ship or buoy the platform is equipped with a set of three gps antennas allowing determination of the sound source position at times of signal transmission and reception merging the satellite and acoustic data allows determination of the transponder network location in global reference frame coordinates data processing to date suggests repeatabilities of 0 8 cm north and 3 9 cm east in the seafloor transponder network position relative to reference points on vancouver island

monitoring landslides and tectonic motions with the permanent scatterers technique spaceborne differential synthetic aperture radar interferometry dinsar has already proven its potential for mapping ground deformation phenomena e g volcano dynamics however atmospheric disturbances as well as phase decorrelation have prevented hitherto this technique from achieving full operational capability these drawbacks are overcome by carrying out measurements on a subset of image pixels corresponding to pointwise stable reflectors permanent scatterers ps and exploiting long temporal series of interferometric data results obtained by processing 55 images acquired by the european space agency esa ers sar sensors over southern california show that the ps approach pushes measurement accuracy very close to its theoretical limit about 1 mm allowing the description of millimetric deformation phenomena occurring in a complex fault system a comparison with corresponding displacement time series relative to permanent gps stations of the southern california integrated gps network scign is carried out moreover the pixel by pixel character of the ps analysis allows the exploitation of individual phase stable radar targets in low coherence areas this makes spaceborne interferometric measurements possible in vegetated areas as long as a sufficient spatial density of individual isolated man made structures or exposed rocks is available the evolution of the ancona landslide central italy was analysed by processing 61 ers images acquired in the time span between june 1992 and december 2000 the results have been compared with deformation values detected during optical levelling campaigns ordered by the municipality of ancona the characteristics of ps gps and optical levelling surveying are to some extent complementary a synergistic use of the three techniques could strongly enhance quality and reliability of ground deformation monitoring d 2002 elsevier science b v all rights reserved

an estimation method for effective stress changes in a reservoir from 4d seismics data advances in seismics acquisition and processing and the widespread use of 4d seismics have made available reliable production induced subsurface deformation data in the form of overburden time shifts inversion of these data is now beginning to be used as an aid to the monitoring of a reservoir s effective stress past solutions to this inversion problem have relied upon analytic calculations for an unrealistically simplified subsurface which can lead to uncertainties to enhance the accuracy of this approach a method based on transfer functions is proposed in which the function itself is calibrated using numerically generated overburden strain deformation calculated for a small select group of reference sources this technique proves to be a good compromise between the faster but more accurate history match of the overburden strain using a geomechanical simulator and the slower less accurate analytic method synthetic tests using a coupled geomechanical and fluid flow simulator for the south arne field confirm the efficacy of the method application to measured time shifts from observed 4d seismics indicates compartmentalization in the tor reservoir more heterogeneity than is currently considered in the simulation model and moderate connectivity with the overlying ekofisk formation

monitoring of fluid injection and soil consolidation using surface tilt measurements temporal variations of surface tilt may be used for the noninvasive monitoring of subsurface volume change such volume changes may accompany settlement near structures the response due to fluid injection or withdrawal and excavation related activity we outline a methodology for using tilt data to estimate volume changes within poroelastic media the expressions relating subsurface volume change and surface tilt are simple and compact offering the possibility of real time monitoring the inversion of actual tilt data from a site near raymond calif generates images of fluid withdrawal from a complex fracture zone about 30 m below the surface volume changes are confined to an elongated north south zone in agreement with independent well test data we have also applied the methodology for the inversion of surface tilt to data from a grout injection experiment in los banos the technique enables us to monitor grout migration through a porous gravel

influence of pore morphology on the durability of sedimentary building stones from aragon spain subjected to standard salt decay tests the aim of the present article is to identify the influence of the pore morphology on the physical behaviour and durability of natural stone fifteen sedimentary rocks commonly used in the cultural and architectural heritage of aragon spain were characterized the petrography porous structure fluid transport properties and durability of these rocks were analysed they were classified into two different groups according to the results of the different tests for each of these groups the physical behaviour was established a principal components analysis was used in order to examine the correlation between pore structure hydric properties and durability the results show that the percentage of pore throats 0 1 m control the fluid transport properties have an important influence on stone durability and can be used to predict resistance to salt decay while the average pore size does not stones with a high percentage of pore throats 0 1 m are less susceptible to salt decay than stones with higher pore size if their pore network is characterized by high tortuosity and low connectivity

quantifying rates of coastal progradation from sediment volume using gpr and osl the holocene fill of guichen bay south east south australia guichen bay on the south east coast of south australia faces west towards the prevailing westerly winds of the southern ocean the bay is backed by a 4 km wide holocene beach ridge plain with more than 100 beach ridges the morphology of the guichen bay strandplain complex shows changes in the width length height and orientation of beach ridges a combination of geomorphological interpretation shallow geophysics and existing geochronology is used to interpret the holocene fill of guichen bay six sets of beach ridges are identified from the interpretation of orthorectified aerial photographs the ridge sets are distinguished on the basis of beach ridge orientation and continuity a 2 25 km ground penetrating radar gpr profile across the beach ridges reveals the sedimentary structures and stratigraphic units the beach ridges visible in the surface topography are a succession of stabilized foredunes that overlie progradational foreshore and upper shoreface sediments the beach progrades show multiple truncation surfaces interpreted as storm events the gpr profile shows that there are many more erosion surfaces in the subsurface than beach ridges on the surface the width and dip of preserved beach progrades imaged by gpr shows that the shoreface has steepened from around 2 9 to around 7 5 the changes in beach slope are attributed to increasing wave energy associated with beach progradation into deeper water as guichen bay was infilled at the same time the thickness of the preserved beach progrades increases slightly as the beach prograded into deeper water using the surface area of the ridge sets measured from the orthophotography and the average thickness of upper shoreface foreshore and coastal dune sands interpreted from the gpr profile the volume of holocene sediments within three of the six sets of beach ridge accretion has been calculated combining optically stimulated luminescence osl ages and volume calculations rates of sediment accumulation for ridge sets 3 4 and 5 have been estimated linear rates of beach ridge progradation appear to decrease in the mid holocene however the rates of sediment accumulation calculated from beach volumes have remained remarkably consistent through the mid to late holocene this suggests that sediment supply to the beach has been constant and that the decrease in the rate of progradation is due to increasing accommodation space as the beach progrades into deeper water changes in beach ridge morphology and orientation reflect environmental factors such as changes in wave climate and wind regime

discrimination between pressure and fluid saturation changes from time lapse seismic data explicit expressions for computing saturation and pressure related changes from time lapse seismic data have been derived and tested on a real time lapse seismic data set necessary input is near and far offset stacks for the baseline seismic survey and the repeat survey the method has been tested successfully in a segment where pressure measurements in two wells verify a pore pressure increase of 5 to 6 mpa between the baseline survey and the monitor survey estimated pressure changes using the proposed relationships fit very well with observations between the baseline and monitor seismic surveys 27 of the estimated recoverable hydrocarbon reserves were produced from this segment the estimated saturation changes also agree well with observed changes apart from some areas in the water zone that are mapped as being exposed to saturation changes which is unlikely saturation changes in other segments close to the original oil water contact and the top reservoir interface are also estimated and conf

salt weathering influence of evaporation rate supersaturation and crystallization pattern micro and macroscale experiments which document the dynamics of salt damage to porous stone have yielded data which expose weaknesses in earlier interpretations previously unexplained differences are found in crystal morphology crystallization patterns kinetics and substrate damage when comparing the growth of mirabilite na2so4 10h2o and thenardite na2so4 versus halite nacl the crystallization pattern of sodium sulphate was strongly affected by relative humidity rh while a lesser rh effect was observed for sodium chloride macroscale experiments confirmed that mirabilite crystallizing at rh 50 per cent and thenardite crystallizing at rh 50 per cent tend to form subflorescence in highly localized areas under conditions of constant rh and temperature this crystallization pattern was more damaging than that of halite since halite tended to grow as efflorescence or by filling the smallest pores of the stone in a homogeneous fashion a result which contradicts wellman and wilson s theoretical model of salt damage low rh promoted rapid evaporation of saline solutions and higher supersaturation levels resulting in the greatest damage to the stone in the case of both sodium sulphate and sodium chloride crystallization at any particular crystallization condition sodium chloride tended to reach lower supersaturation levels resulting in the crystallization of isometric crystals and created negligible damage while sodium sulphate reached higher supersaturation ratios resulting in non equilibrium crystal shapes resulting in significant damage esem showed no damage from sodium sulphate due to hydration instead after water condensation on thenardite crystals rapid dissolution followed by precipitation of mirabilite took place resulting in stone damage by means of crystallization pressure generation it is concluded that salt damage due to crystallization pressure appears to be largely a function of solution supersaturation ratio and location of crystallization these key factors are related to solution properties and evaporation rates which are constrained by solution composition environmental conditions substrate properties and salt crystallization growth patterns when combined with a critical review of salt damage literature these experiments allow the development of a model which explains variations in damage related to combinations of different salts substrates and environmental conditions

the influence of petrophysical properties on the salt weathering of porous building rocks the influence of pore structure water transport properties and rock strength on salt weathering is evaluated by means of a thorough rock characterisation and a statistical analysis the pore structure was described in terms of its porosity pore size distribution quantified by mean pore radius and specific surface area density and water transport was characterised by means of water permeability saturated flow and capillary imbibition unsaturated flow whilst the rock strength test was carried out using uniaxial compressive strength compressional and shear wave velocities dynamic elastic constants and waveform energy and attenuation were obtained from the digital analysis of the transmitted signal a principal component analysis and a stepwise multiple regression model was carried out in order to examine the direct relationships between salt weathering and petrophysical properties from the principal component analysis two main components were obtained and assigned a petrophysical meaning the first component is mostly linked to mechanical properties porosity and density whereas the second component is associated with the water transport and pore structure salt weathering quantified by the percentage of weight loss after salt crystallisation was included in both principal components showing its dependence on their petrophysical properties the stepwise multiple regression analysis found that rock strength has a predominant statistical weight in the prediction of salt weathering with a minor contribution of water transport and pore structure parameters

contour scaling of a sandstone by salt weathering under simulated hot desert conditions a laboratory study has been used to investigate relationships between salts and contour scaling a weathering feature commonly observed on rock surfaces in salt rich environments surface disaggregation and essentially surface parallel cracks were produced in sandstone blocks using 10 per cent solutions of sodium sulphate and magnesium sulphate applied daily to single exposed surfaces for sixty days a control block soaked once in saturated magnesium sulphate and subsequently wetted daily with distilled water showed extensive surface disaggregation but no cracking both surface disaggregation and subsurface cracking were associated with relative concentrations of microcrystalline salt a tentative model of contour scaling is proposed which involves linking together potential cracks by salt induced fracturing of intervening crack stopping grains further control blocks treated respectively with 10 per cent and saturated sodium chloride showed no evidence of subsurface cracking and only limited surface disaggregation of the saturated block

estimating fluid induced stress change from observed deformation author s vasco dw harness p pride s hoversten m abstract the authors 2016 published by oxford university press on behalf of the royal astronomical society observed deformation is sensitive to a changing stress field within the earth however there are several impediments to a direct inversion of geodetic measurements for changes in stress estimating six independent components of stress change from a smaller number of displacement or strain components is inherently non unique the reliance upon surface measurements leads to a loss of resolution due to the attenuation of higher spatial frequencies in the displacement field with distance from a source we adopt a technique suited to the estimation of stress changes due to the injection and or withdrawal of fluids at depth in this approach the surface displacement data provides an estimate of the volume change responsible for the deformation rather than stress changes themselves the inversion for volume change is constrained by the fluid fluxes into and out of the reservoir the distribution of volume change is used to calculate the displacements in the region above the reservoir estimates of stress change follow from differentiating the displacement field in conjunction with a geomechanical model of the overburden we apply the technique to interferometric synthetic aperture radar insar observations gathered over a petroleum reservoir in the san joaquin valley of california an analysis of the insar range changes reveals that the stress field in the overburden varies rapidly both in space and in time the inferred stress variations are found to be compatible with the documented failure of a well in the field

on the use of quasi static deformation to understand reservoir fluid flow deformation above a producing reservoir provides a valuable source of information concerning fluid flow and flow properties quasi static deformation occurs when the displacements are so slow that we may neglect inertial terms in the equations of motion we present a method for inferring reservoir volume change and flow properties such as permeability from observations of quasi static deformation such displacements may represent surface deformation such as tilt leveling interferometric synthetic aperture radar insar or bathymetry observations or subsurface deformation as inferred from time lapse seismic surveys in our approach the equation for fluid flow in a deforming reservoir provides a mapping from estimated fractional volume changes to reservoir permeability variations if the reservoir behaves poroelastically over the interval of interest all the steps in this approach are linear thus the inference of reservoir permeability from deformation data becomes a linear inverse problem in an application to the wilmington oil field in california we find that observed surface displacements obtained by leveling and insar are indeed compatible with measured reservoir volume fluxes we find that the permeability variations in certain layers coincide with fault block boundaries suggesting that in some cases faults are controlling fluid flow at depth

a coupled inversion of pressure and surface displacement a coupled inversion of transient pressure observations and surface displacement measurements provides an efficient technique for estimating subsurface permeability variations the methodology has the advantage of utilizing surface observations which are typically much less expensive than measurements requiring boreholes furthermore unlike many other geophysical observables the relationship between surface deformation and reservoir pore fluid volume changes is relatively well understood our treatment enables us to partition the estimation problem into a sequence of three linear subproblems an application of the approach to a set of tilt and borehole pressure data from the raymond field site in california illustrates its efficiency and utility the observations are associated with a well test in which fluid is withdrawn from a shallow fracture zone during the test 13 tiltmeters recorded the movement of the ground surface simultaneously nine transducers measured pressure changes in boreholes intersecting the fracture system we are able to image a high permeability north trending channel located within the fracture zone the existence and orientation of this high permeability feature is substantiated by a semiquantitative analysis of some 4000 transient pressure curves

monitoring of ground surface and subsurface deformations at oil sands using radar interferometry abstractconventional monitoring methods such as surveying and tiltmeter require labor intensive and time consuming fieldwork and they are limited to specific locations either survey stations or an array of tiltmeters furthermore none of the studies about the geomechanical inversion of cumulative surface deformations for the inference of subsurface volumetric changes in canadian oil sands has yet been published radar interferometry has been widely used for monitoring surface deformations over a large area in all weather conditions with high accuracy we have developed a method to detect surface deformations by radar interferometry techniques and to estimate subsurface volumetric changes by geomechanical inversion of surface deformation measurements differential interferometric synthetic aperture radar was implemented using first advanced land observation satellite phased array type l band synthetic aperture radar data the resulting interferograms indicated the vertical surface deformations between

durability of carbonate rock as building stone with comments on its preservation carbonate rocks have been extensively used as building stones because of their availability workability and attractiveness unfortunately however some stones suffer from chemical attack or freeze thaw activity the environmental affects especially those due to pollution of the atmosphere are discussed in terms of weathering processes salt crystallization and acid deposition a review of some recent research in relation to deterioration of stone in urban environments is given and carbonate rocks are classified in relation to position within a building geographical location and degree of pollution some comments on stone preservation are provided especially in terms of the properties a preservative should possess

limestones under salt decay tests assessment of pore network dependent durability predictors three portuguese limestones two grainstones semi rijo and moca creme commercial types and a travertine were subjected to salt crystallisation test en 12370 1999 grainstones specimens showed higher weight loss than the travertine ones results are discussed using parametric and nonparametric statistics in relation to pore space characteristics that have been considered durability predictors evaluated at the macroscopic water imbibition and microscopic mercury injection porosimetry levels several of the pore space parameters indicate differences between grainstones and travertine but these differences are much lower than the differences in weight loss results of the durability dimensional estimator dde seem to present a discrepancy with higher values in the rock type having lower weight loss travertine additionally weathering patterns of travertine samples show marked irregularities a feature that is not assessed by weight loss these irregularities are attributed to heterogeneous spatial distribution of detritic components a feature that is not assessed by pore space parameters comparing the grainstones moca creme showed higher values of mass loss and several durability predictors suggested noteworthy differences in relation to semi rijo however these differences are much lower than differences in weight loss calculated crystallisation pressures are even higher for semi rijo it is proposed that petrographical aspects of moca creme namely heterogeneity related to the presence of bioclasts and veinlets could contribute to explain the higher weathering susceptibility of this rock type these results highlight the need to include petrographical features in assessments of durability and the usefulness of visual description on the characterization of salt weathering

salt and ice crystallisation in porous sandstones salt and ice crystallisation in the pore spaces causes major physical damage to natural building stones the damaging effect of these processes can be traced back to physically induced stress inside of the rock while crystallizing the increasing scientific research done during the past century has shown that there are numerous parameters that have an influence on the weathering resulting from these processes however the working mechanisms of the stress development within the rock and its material dependency are still subject to discussion this article gives an overview of salt and ice weathering additionally laboratory results of various sandstones examined are presented salt crystallisation tests and freeze thaw tests were done to obtain information about how crystallisation weathering depends on material characteristics such as pore space water transportation and mechanical features simultaneous measuring of the length alternating during the salt and ice crystallisation has revealed detailed information on the development of crystal in the pore spaces as well as the development of stress these findings can help to understand the damaging mechanisms

characterization of shallow geology by high frequency seismic noise tomography summary to study the applicability of the passive seismic interferometry technique to near surface geological studies seismic noise recordings from a small scale 2 d array of seismic stations were performed in the test site of nauen germany rayleigh wave green s functions were estimated for different frequencies a tomographic inversion of the traveltimes estimated for each frequency from the green s functions is then performed allowing the laterally varying 3 d surface wave velocity structure below the array to be retrieved at engineering geotechnical scales furthermore a 2 d s wave velocity cross section is obtained by combining 1 d velocity structures derived from the inversion of the dispersion curves extracted at several points along a profile where other geophysical analyses were performed it is shown that the cross section from passive seismic interferometry provides a clear image of the local structural heterogeneities that are in excellent agreement with georadar and geoelectrical results such findings indicate that the interferometry analysis of seismic noise is potentially of great interest for deriving the shallow 3 d velocity structure in urban areas

radar interferometry and its application to changes in the earth s surface geophysical applications of radar interferometry to measure changes in the earth s surface have exploded in the early 1990s this new geodetic technique calculates the interference pattern caused by the difference in phase between two images acquired by a spaceborne synthetic aperture radar at two distinct times the resulting interferogram is a contour map of the change in distance between the ground and the radar instrument these maps provide an unsurpassed spatial sampling density 100 pixels km 2 a competitive precision 1 cm and a useful observation cadence 1 pass month 1 they record movements in the crust perturbations in the atmosphere dielectric modifications in the soil and relief in the topography they are also sensitive to technical effects such as relative variations in the radar s trajectory or variations in its frequency standard we describe how all these phenomena contribute to an interferogram then a practical summary explains the techniques for calculating and manipulating interferograms from various radar instruments including the four satellites currently in orbit ers 1 ers 2 jers 1 and radarsat the next chapter suggests some guidelines for interpreting an interferogram as a geophysical measurement respecting the limits of the technique assessing its uncertainty recognizing artifacts and discriminating different types of signal we then review the geophysical applications published to date most of which study deformation related to earthquakes volcanoes and glaciers using ers 1 data we also show examples of monitoring natural hazards and environmental alterations related to landslides subsidence and agriculture in addition we consider subtler geophysical signals such as postseismic relaxation tidal loading of coastal areas and interseismic strain accumulation we conclude with our perspectives on the future of radar interferometry the objective of the review is for the reader to develop the physical understanding necessary to calculate an interferogram and the geophysical intuition necessary to interpret it

investigations into provenance and properties of ancient building sandstones of the zittau gorlitz region upper lusatia eastern saxony germany

electrical resistivity tomography monitoring of permafrost in solid rock walls 1 this article describes the first attempt to conduct electrical resistivity tomography ert in solid permafrost affected rock faces electrode design instrument settings and processing routines capable of measuring under relevant conditions were developed four transects with nw ne east e and south s aspects were installed in solid rock faces between matter valley and turtmann valley switzerland at 3070 3150 m above sea level dc resistivity in the transects was measured repeatedly during the summer and compared by applying a time lapse inversion routine resistivity values were calibrated using observed rock surface conditions of thawed damp rocks 1 8 k m deeply frozen rocks 18 80 k m and the transition from damp thawed to frozen rocks 8 18 k m mean surface layer resistivities of transects respond to air temperatures below 0 c with a rapid increase by a factor of 1 4 to 2 9 from values of 12 15 k m to values of 22 31 k m rock layers at depths of 2 6 m display a general trend of resistivity decrease in summer corresponding to a persistent thawing process their response to anomalously cool august temperatures occurs with a time lag of 2 to 4 weeks only transects e ne and nw display persistent high resistivity permafrost bodies 50 k m mostly at depths of 6 10 m the maximum thaw depth of a continuous thawing front above permafrost is 6 m however the ert results emphasize the role of heat transfer by deep reaching cleft water systems thus permafrost occurs in lenses rather than layers ert provides rapid detection of ice and water distribution in permafrost affected bedrock

landform characterization using geophysics recent advances applications and emerging tools abstract this paper presents an overview of the strengths and limitations of existing and emerging geophysical tools for landform studies the objectives are to discuss recent technical developments and to provide a review of relevant recent literature with a focus on propagating field methods with terrestrial applications for various methods in this category including ground penetrating radar gpr electrical resistivity er seismics and electromagnetic em induction the technical backgrounds are introduced followed by section on novel developments relevant to landform characterization for several decades gpr has been popular for characterization of the shallow subsurface and in particular sedimentary systems novel developments in gpr include the use of multi offset systems to improve signal to noise ratios and data collection efficiency amongst others and the increased use of 3d data multi electrode er systems have become popular in recent years as they allow for relatively fast and detailed mapping novel developments include time lapse monitoring of dynamic processes as well as the use of capacitively coupled systems for fast non invasive surveys em induction methods are especially popular for fast mapping of spatial variation but can also be used to obtain information on the vertical variation in subsurface electrical conductivity in recent years several examples of the use of plane wave em for characterization of landforms have been published seismic methods for landform characterization include seismic reflection and refraction techniques and the use of surface waves a recent development is the use of passive sensing approaches the use of multiple geophysical methods which can benefit from the sensitivity to different subsurface parameters is becoming more common strategies for coupled and joint inversion of complementary datasets will once more widely available benefit the geophysical study of landforms three cases studies are presented on the use of electrical and gpr methods for characterization of landforms in the range of meters to 100 s of meters in dimension in a study of polygonal patterned ground in the saginaw lowlands michigan usa electrical resistivity tomography was used to characterize differences in subsurface texture and water content associated with polygon swale topography also a sand filled thermokarst feature was identified using electrical resistivity data the second example is on the use of constant spread traversing cst for characterization of large scale glaciotectonic deformation in the ludington ridge michigan multiple cst surveys parallel to an 60 m high cliff where broad 100 m synclines and narrow clay rich anticlines are visible illustrated that at least one of the narrow structures extended inland a third case study discusses internal structures of an eolian dune on a coastal spit in new zealand both 35 and 200 mhz gpr data which clearly identified a paleosol and internal sedimentary structures of the dune were used to improve understanding of the development of the dune which may shed light on paleo wind directions

hydraulic properties of injection formations constrained by surface deformation author s shirzaei m manga m zhai g abstract 2019 the author s wastewater injection over the past decade has increased seismicity in the central usa in some cases accompanied by detectable surface uplift here we use this uplift to constrain subsurface properties and pore pressure evolution we apply an advanced multitemporal interferometric algorithm to 35 synthetic aperture radar images acquired by alos satellite over four years before the 2012 earthquake sequence in east texas where large volumes of wastewater are disposed at depths of 800 m and 1800 m to solve for the hydraulic diffusivity of the injection layers we jointly inverted the injected volume and uplift data considering a poroelastic layered half space we find diffusivity values of 0 3 0 1 m 2 s and 0 7 0 15 m 2 s for shallow and deep injection layers respectively which combined with seismically derived bulk moduli yields permeability values of 5 5 2 6 10 14 m 2 and 1 9 0 25 10 13 m 2 for these layers consistent with permeability range reported for rodessa formation and well test values hydraulic conductivity determines the evolution of pore pressure and thus the origin and location of induced seismicity this study highlights the value of geodetic observations to constrain key hydrogeological properties of injection layers and to monitor the evolution of the subsurface pressure change

natural stones for monuments their availability for restoration and evaluation this paper represents the introduction to the volume focused on the various aspects of natural stone research from the topic issues studied recently four major aspects are covered 1 availability of certain stone types for monuments 2 strategies aiming to strengthen our knowledge of past resources through the establishment of natural stone databases and inventories 3 evaluation of natural stone properties and assessment of the compatibility of repair stones and 4 decay studies of natural stone on monuments and on natural exposures this paper also aims to highlight the importance of the use of local stone resources a practice that has seriously declined during the 20th century in most of the industrialized countries the availability of natural stone from monuments is also discussed in terms of sandstones and travertine in the czech republic and hungary as a typical example natural stone has become the expression to describe the versatile durable and aesthetically plausible building materials currier 1960 from the very beginning of civilization important structures and monuments were built from or were principally based on natural stone the use of local stone resources was mostly in balance with the local environment although highly durable when properly applied no stone type can be considered immortal schaffer 1932 and most of the stone varieties are affected by a polluted atmosphere winkler 1997 deteriorated stone on monuments should be preferably replaced by stone varieties of the same composition from the same quarries however this is often not possible and so stone having similar properties and appearance must be sourced p ikryl 2007 the main aim of this research is to find compatible stones in terms of appearance and geochemical physical properties this task requires a thorough understanding of both the rock properties and its response to external conditions and weathering agents availability of natural stone

recent subsidence of the venice lagoon from continuous gps and interferometric synthetic aperture radar 1 coastal regions are increasingly affected by larger storms and rising sea level predicted by global warming models aggravating the situation in the city of venice where tidal induced seasonal flooding coupled with natural and anthropogenic subsidence have been perennial problems in light of accelerated efforts to protect venice from the rise in sea level we assess land subsidence in the venice lagoon over the last decade through a combined analysis of gps position time series from 2001 55 to 2011 00 for four stations installed by the magistrato alle acque di venezia and thousands of observations of insar permanent scatterers using radarsat 1 images from 2003 3 to 2007 85 we determine that the northern lagoon subsides at a rate of 2 3 mm yr whereas the southern lagoon subsides at 3 4 mm yr the city of venice continues to subside at a rate of 1 2 mm yr in contrast to geodetic studies in the last decade of the 20th century suggesting that subsidence has been stabilized the gps results indicate a general eastward tilt in subsidence and that the natural subsidence rate related to the retreat of the adriatic plate subducting beneath the apennines is at least 0 4 0 6 mm yr our combined gps and insar analysis demonstrates high spatial resolution in the vertical direction with a precision of 0 1 0 2 mm yr with respect to a global reference frame continued efforts to secure the city of venice from flooding must also take into account the significant local and regional subsidence rates as well as the expected rise in sea level

nonlinear subsidence rate estimation using permanent scatterers in differential sar interferometry discrete and temporarily stable natural reflectors or permanent scatterers ps can be identified from long temporal series of interferometric sar images even with baselines larger than the so called critical baseline this subset of image pixels can be exploited successfully for high accuracy differential measurements the authors discuss the use of ps in urban areas like pomona ca showing subsidence and absidence effects a new approach to the estimation of the atmospheric phase contributions and the local displacement field is proposed based on simple statistical assumptions new solutions are presented in order to cope with nonlinear motion of the targets

chemical denudation in arctic alpine latnjavagge swedish lapland in relation to regolith as assessed by radio magnetotelluric geophysical profiles chemical denudation in arctic alpine latnjavagge swedish lappland in relation to regolith as assessed by radio magnetotelluric geophysical profiles

influence of pore system characteristics on limestone vulnerability a laboratory study hyblean limestone of oligo miocene age was widely used as a construction material in the architectural heritage of eastern sicily italy among them the so called pietra bianca di melilli melilli limestone and calcare di siracusa syracuse limestone were prized for their attractive appearance ease of quarrying and workability syracuse limestone shows general weathering whereas melilli limestone is better preserved and only differential erosion or superficial exfoliation can be detected in monuments the cause of the different behavior of these two limestones was investigated from the petrographic and petrophysical points of view the saturation coefficient is higher in melilli limestone and ultrasound measurements indicate that it is less compact than syracuse limestone so that melilli limestone could deteriorate more easily than syracuse limestone however pore interconnections and the size of very small pores play the main role in the durability of both materials the irregularity of the syracuse pore system and its greater number of micropores hinder water flow through the exterior promote stress in pore structure and favor the development of scaling as confirmed by salt crystallization tests in melilli limestone the low concentration of micropores and fast water evaporation allow solutions to reach the surface more easily resulting in less damaging efflorescence

joint inversion in coupled quasi static poroelasticity geodetic surveys now provide detailed time series maps of anthropogenic land subsidence and uplift due to injection and withdrawal of pore fluids from the subsurface a coupled poroelastic model allows the integration of geodetic and hydraulic data in a joint inversion and has therefore the potential to improve the characterization of the subsurface and our ability to monitor pore pressure evolution we formulate a bayesian inverse problem to infer the lateral permeability variation in an aquifer from geodetic and hydraulic data and from prior information we compute the maximum a posteriori map estimate of the posterior permeability distribution and a gaussian approximation of the posterior computing the map estimate requires the solution of a large scale minimization problem subject to the poroelastic equations for which we propose an efficient newton conjugate gradient optimization algorithm the covariance matrix of the gaussian approximation of the posterior is given by the inverse hessian of the log posterior which we construct by exploiting low rank properties of the data misfit hessian first and second derivatives are computed using adjoints of the time dependent poroelastic equations allowing us to fully exploit transient data using three increasingly complex model problems we find the following general properties of poroelastic inversions augmenting standard hydraulic well data by surface deformation data improves the aquifer characterization surface deformation contributes the most in shallow aquifers but provides useful information even for the characterization of aquifers down to 1 km in general it is more difficult to infer high permeability regions and their characterization requires frequent measurement to resolve the associated short response timescales in horizontal aquifers the vertical component of the surface deformation provides a smoothed image of the pressure distribution in the aquifer provided that the mechanical properties are known coupled poroelastic inversion is therefore a promising approach to detect flow barriers and to monitor pore pressure evolution

fluid pressure arrival time tomography estimation and assessment in the presence of inequality constraints with an application to production at the krechba field algeria deformation in the overburden proves useful in deducing spatial and temporal changes in the volume of a producing reservoir based on these changes we have estimated diffusive traveltimes associated with the transient flow due to production and then as the solution of a linear inverse problem the effective permeability of the reservoir an advantage of the approach based on traveltimes as opposed to one based on the amplitude of surface deformation is that it is much less sensitive to the exact geomechanical properties of the reservoir and overburden inequalities constrain the inversion under the assumption that the fluid production only results in pore volume decreases within the reservoir the formulation has been applied to satellite based estimates of deformation in the material overlying a thin gas production zone at the krechba field in algeria the peak displacement after three years of gas production is found to be approximately 0 5 cm overlying the eastern margin of the anticlinal structure defining the gas field using data from 15 irregularly spaced images of range change we have calculated the diffusive traveltimes associated with the startup of a gas production well the inequality constraints were incorporated into the estimates of model parameter resolution and covariance improving the resolution by roughly 30 to 40

utilizing the onset of time lapse changes a robust basis for reservoir monitoring and characterization time lapse monitoring is useful for imaging changes in geophysical attributes due to fluid flow in trying to use time lapse data for reservoir characterization difficulties often arise when relating changes in geophysical observations to changes in fluid saturation and pressure as an alternative approach for reservoir monitoring and characterization we introduce the idea of an onset time the time at which a measured quantity such as a seismic traveltime or a reflection amplitude begins to deviate from its background value we illustrate the idea and demonstrate its utility through the consideration of traveltimes recorded by the continuous active source seismic monitoring system at the frio pilot site near houston texas the system which transmits an elastic wave every 15 min is used to monitor the movement of carbon dioxide injected into a permeable sand formation from these data we can estimate the onset of changes in seismic traveltimes to six receivers in an adjacent borehole numerical simulation and synthetic tests indicate that the onset times are not very sensitive to the method used to compute the effective fluid bulk modulus and correspondingly the seismic compressional velocity rather the onset times are strongly influenced by saturation changes within the formation specifically by the break through time of the injected fluid phase by means of an iterative inversion algorithm we use the onset times to estimate permeability variations between the boreholes at the frio pilot site the authors 2014 published by oxford university press on behalf of the royal astronomical society

in situ shear wave velocity from multichannel analysis of surface waves masw tests at eight norwegian research sites the multichannel analysis of surface waves masw technique which is used to determine shear wave velocity vs and hence small strain stiffness gmax has recently generated considerable interest in the geophysics community this is because of the ease of carrying out the test and analysis of the data the objective of this work was to assess the repeatability accuracy and reliability of masw surface wave measurements for use in engineering studies tests were carried out at eight well characterized norwegian clay silt and sand research sites where vs had already been assessed using independent means as well as being easy and quick to use the masw technique gave consistent and repeatable results and the masw vs profiles for the clay sites were similar to those obtained from other techniques reasonable results were also obtained for the silt and sand sites with the best result being obtained for the finer silt this work also confirms that masw vs clay profiles are comparable to those obtained

geophysical evidence for peat basin morphology and stratigraphic controls on vegetation observed in a northern peatland vegetation patterns in peatlands suggest autogenic peatland development and hydrological processes are controlling factors in peatland evolution these processes regulate vegetation ordination by influencing ph and nutrient availability at the peat surface geophysical studies in caribou bog a 2200 hectare peatland in central maine indicate a close correlation between underlying geologic deposits and dominant vegetation type the location of pools within the bog also appears to be related to subsurface geologic materials electrical resistivity imaging along a 1 km transect across the central unit of caribou bog resolved underlying lake sediment and glacio marine clay thickness as well as variability in depth to glacial till ground penetrating radar precisely defined the organic rich lake sediment the glacio marine interface and elevated till surfaces where peat thickness is less than 10 m direct verification of peat and lake sediment thickness in addition to samples of the glacio marine and till deposits constrained the geophysical interpretation wooded heath wh interspersed with occasional sphagnum lawn occurs where lake sediment and glacio marine clay accumulation is thickest abrupt thinning of both layers such that peat rests directly on till in places correlates with a sharp transition to shrub heath dominated vegetation a major open pool area located within the wh coincides with a localized sandy mineral soil lake sediment contact at the base of the bog the geophysical data suggest the underlying double basin system influences peatland development and dictates vegetation patterning limited groundwater elevation data suggest that sub organic sediment stratigraphy mapped with geophysics regulates water levels at the peat surface exerting a control on vegetation patterning the major pool area located between the basins appears to reflect isolation of stagnant water at a point where peat development is incomplete and thus suggests that pools exist concurrent with peatland formation

the processes dominating ca dissolution of limestone when exposed to ambient atmospheric conditions as determined by comparing dissolution models in order to gain a clearer understanding of the decay mechanisms operating in limestones and to determine the main damage factors at different exposure environments calcite dissolution models from the literature were compared the models recognise three major stone decay mechanisms attack by air pollutants dry deposition dissolution in clean rain karst effect and dissolution caused by neutralisation of rain acidity acidity effect these models were fitted to experimental data obtained from the run off water analysis running over the so called massangis limestone exposed under ambient conditions in five sites in belgium the models demonstrate that different processes dominate the limestone dissolution at the different sites with dry deposition of air pollutants especially so2 being the principal process involved

monitoring the geologic storage of carbon dioxide using multicomponent sar interferometry monitoring the geologic storage of carbon dioxide using multi component sar interferometry alessio rucci 1 d w vasco 2 and fabrizio novali 1 tele rilevamento europa milano italy berkeley laboratory university of california berkeley california 94720 summary combining interferometric synthetic aperture radar insar data from ascending and de scending orbits we estimate both quasi vertical and quasi east west displacements for a region in central algeria an area encompassing an active large scale carbon dioxide stor age project the in salah gas storage project the surface deformation associated with the injection into three horizontal wells is clearly visible in the insar estimates we find that the addition of the quasi horizontal displacement data enables us to discriminate between source models producing similar vertical displacements in particular predictions from a model consisting of a distribution of volume changes restricted to the reservoir depth interval satisfies the quasi vertical data but does not match the quasi east west displace ment data however aperture changes on sub vertical damage zones intersecting each of the injection wells give rise to displacements matching both the quasi east west and vertical components in all cases we can match the observations with the most significant volume and aperture changes in regions immediately surrounding the injection wells key words interferometry deformation inverse problem

gpr stratigraphy of a large active dune on parengarenga sandspit new zealand the parengarenga sandspit figure 1 is new zealand s only coastal source of silica sand for glass manufacturing concerns about the environmental effects of sand extraction from the harbor mouth in the last two decades led the extraction companies to instigate a monitoring program the parengarenga beach dune monitoring program started in 1982 since that time cross profiles have been surveyed twice a year from below chart datum cd to landward of the sparsely vegetated foredune system this is the longest continuous record of beach profile measurement in new zealand and provides important information on the behavior of this coastal spit system parnell 1997 the sedimentary material in parengarenga sandspit consists of 93 5 quartz and has a very uniform fine sandy grain size median 193 microns from near shore to the beach and in the dunes

painting the near surface using geology geophysics and satellites a smooth interpolation of a sparse uphole survey may be the main tool available for modeling the near surface in desert areas an uphole survey does not properly define sharp near surface velocity changes associated with lithologic and topographic variations such as cliffs canyons or outcrops which may be delineated by satellite imagery instead we present a patchy interpolation technique to build a consistent near surface model the algorithm is based on k means clustering to integrate geological geophysical and remote sensing information a somewhat arbitrary aspect of the method is the choice of how many clusters are used in segregating the data linking this parameter to surface geologic formations may be inadequate because p or s wave velocities are unlikely to have a sufficiently unique correlation with geologic age and lithology we suggest an empirical criterion improvement in the seismic stack section achieved by processing with parameters derived by various clustering choices and data t

a mathematical model for compaction in sedimentary basins summary a mathematical model for the non equilibrium compaction of clay rocks in sedimentary basins is formulated the model generalizes those of earlier authors the simplest assumptions are made concerning the rheology and diagenesis is neglected in this case we show that the model reduces to a generalized consolidation equation which for the classical darcy flow is a non linear diffusion equation for the porosity with a free boundary the model is non dimensionalized and it is shown that solutions depend on one significant dimensionless parameter a which is the ratio of the darcy flow rate and the sedimentation rate the model is solved numerically and asymptotic descriptions of the solutions are given for the cases of large and small a

comparison of gpr 2d resistivity and traditional techniques for the subsurface exploration of the oschingen landslide swabian alb germany abstract numerous rotational and translational slides of different sizes cause considerable economic damage in the swabian alb sw germany and are a challenge for risk assessment the oschingen landslide is a typical example for landslides occurring along the escarpment lithology consists of jurassic sedimentary rocks involving clays overlain by marls and limestones a combination of traditional methods drilling mapping inclinometers and geophysical techniques 2d resistivity ert ground penetrating radar gpr was applied to gain knowledge about the thickness and internal structure of the landslide the drillings and penetration tests provided point information on landslide extent structure and material involved in general all inclinometers showed very little movement if at all the gpr results were affected by strong signal attenuation and by overhead reflections from the nearby woods despite these general obstacles for the application of gpr on landslides near surface sediment structures were detected in the 2d resistivity sections higher resistive limestone blocks reaching 10 15 m in thickness could be clearly distinguished from the underlying bedrock the detailed two dimensional data of the electrical resistivity tomography ert along with the rather high survey speed turned out to be the best choice to gain detailed spatial information on thickness and extent of the slope movement the measured profiles coincide with the gpr data and correspond to borehole data surprisingly all results from the applied methods clearly detected the absence of large landslide blocks in the north west of the study area this finding could not be concluded from local geomorphology of this area regarding the current landslide displacement derived from the inclinometer measurements the large landslide blocks seem to be dormant during the measured period

using surface deformation to image reservoir dynamics the inversion of surface deformation data such as tilt displacement or strain provides a noninvasive method for monitoring subsurface volume change reservoir volume change is related directly to processes such as pressure variations induced by injection and withdrawal the inversion procedure is illustrated by an application to tiltmeter data from the hijiori test site in japan an inversion of surface tilt data allows us to image flow processes in a fractured granodiorite approximately 650 barrels of water injected 2 km below the surface produces a peak surface tilt of the order of 0 8 microradians we find that the pattern of volume change in the granodiorite is very asymmetrical elongated in a north northwesterly direction and the maximum volume change is offset by more than 0 7 km to the east of the pumping well the inversion of a suite of leveling data from the wilmington oil field in long beach california images large scale reservoir volume changes in 12 one to two year increments from 1

quaternary neotectonics of the south aegean arc abstract the sedimentary and tectonic quaternary evolution of the south aegean arc has been interpreted from 8000 line km of sparker seismic reflection profiles the older parts of basins formed by e w trending faults and accumulated hemipelagic sediment younger active faulting trends nnw in the western part of the arc and ene in the eastern arc the ene trending faults record sinistral strike slip motion broadly parallel to the convergence direction of the aegean anatolian and african plates the north south faults in the western arc are similar to those on land in the south peloponnese chronology is estimated from sedimentation rates in cores and from stacked progradational units on basin margins controlled by eustatic changes in sea level the younger fault pattern developed at 0 6 0 8 ma in the western and central arc but progressively younger in the southeastern part of the arc the older basin fill with e w faults is of early quaternary and pliocene age an older regional unconformity corresponds to an early pleistocene unconformity in the cretan basin particularly in the area east of santorini faulting has resulted in startling changes in palaeogeography such that some areas were late pliocene basins positive features during the pleistocene and then subsided 600 m in the last 0 2 ma such rapid basin inversion resulted in uplift of stratified hemipelagic muds which were deformed by creep or failure so that debris flow deposits accumulated in valleys and ponded basins these fundamental tectonic changes in the past two million years indicate that much of the deformation resulting from the interaction of the eurasian african and anatolian aegean plates is taken up at the southern margin of the aegean microplate probably because subduction of the african plate has slowed as a result of collision of continental crust regional fault patterns are a consequence of spatially varying effects of subduction roll back

building stone employed in the historical monuments of eastern sicily italy an example the ancient city centre of catania an archaeometric study of the stone materials employed in the late baroque historical monuments of the ancient city centre of catania was carried out lithological maps of a selection of monuments transferred to a digital format revealed that the stone materials are both magmatic and sedimentary rocks the colours of which are matched in a peculiar type of bichromy particular attention focused on sedimentary rocks which consist of various types of limestone quarried near the city of syracuse hyblean plateau south eastern sicily carbonate rocks were characterised in terms of mineralogy petrography and geochemistry by studying rock samples from both monuments and historical extraction sites results showed that although only one name was historically attributed to the above lithotypes i e pietra di siracusa they were quarried from many locations and as they belong to various geological formations they therefore exhibit great variety in order to examine the durability of hyblean limestones employed in works of cultural heritage interest salt crystallisation tests were carried out according to standard procedure norms uni en 12370 1999 determination of resistance to crystallisation of salts 6p results are consistent with the forms of deterioration observed in the monuments and highlight the close relationship between textural characteristics and damage our purpose is to provide a basic tool which may be useful both for conserving monuments of cultural heritage and for their restoration