the response of black rapids glacier alaska to the denali earthquake rock avalanches 1 we describe the impact of three simultaneous earthquake triggered rock avalanches on the dynamics of black rapids glacier alaska by using spaceborne radar imagery and numerical modeling we determined the velocities of the glacier before and after landslide deposition in 2002 by using a combination of ers 1 ers 2 tandem radarsat 1 and alos palsar synthetic aperture radar data ice velocity above the debris covered area of the glacier increased up to 14 after the earthquake but then decreased 20 by 2005 within the area of the debris sheets mean glacier surface velocity increased 44 within 2 years of the landslides at the downglacier end of the lowest landslide where strong differential ablation produced a steep ice cliff velocities increased by 109 over the same period by 2007 ice velocity throughout the debris area had become more uniform consistent with a constant ice flux resulting from drastically reduced ablation at the base of the debris without further analysis we cannot prove that these changes resulted from the landslides because black rapids glacier displays large seasonal and interannual variations in velocity however a full stokes numerical ice flow model of a simplified glacier geometry produced a reversal of the velocity gradient from compressional to extensional flow after 5 years which supports our interpretation that the recent changes in the velocity field of the glacier are related to landslide induced mass balance changes

spatiotemporal characterization of land subsidence and uplift in phoenix using insar time series and wavelet transforms the effects of land subsidence pose a significant hazard to the environment and infrastructure in the arid alluvial basins of phoenix arizona improving our understanding of the source and mechanisms of subsidence is important for planning and risk management here we employ multitemporal interferometric analysis of large synthetic aperture radar data sets acquired by ers and envisat satellites to investigate ground deformation the ers data sets from 1992 to 1996 and envisat 2003 2010 are used to generate line of sight los time series and velocities in both the ascending and descending tracks the general deformation pattern is consistent among data sets and is characterized by three zones of subsidence and a broad zone of uplift the multitrack envisat los time series of surface deformation are inverted to obtain spatiotemporal maps of the vertical and horizontal deformation fields we use observation wells to provide an in situ independent data set of hydraulic head levels then we analyze vertical interferometric synthetic aperture radar and hydraulic head level time series using continuous wavelet transform to separate periodic signal components and the long term trend the isolated signal components are used to estimate the elastic storage coefficient the inelastic skeletal storage coefficient and compaction time constants together these parameters describe the storage response of an aquifer system to changes in hydraulic head and surface elevation understanding aquifer parameters is useful for the ongoing management of groundwater resources

monitoring of slow ground deformation by ers radar interferometry on the vauvert salt mine france comparison with ground based measurement the differential sar interferometry dinsar technique has been applied to a test site near vauvert france to detect and monitor ground deformation this site corresponds to the location of an industrial exploitation of underground salt using the solution mining technique an area of subsidence has been observed using in situ measurements despite conditions unfavorable for insar because of the vegetal cover we show that radar remote sensing observations provide valuable information which substantially improves our knowledge of the phenomenon an adaptive phase filtering process has been used to improve the coherence level in particular our study shows that the geometry of the subsidence bowl is different to that previously assumed using ground based techniques only the size of the subsidence bowl 8 km is larger than expected this information will be useful for further modeling of the deformation and to improve the coverage of the in situ measurement networks it also shows that radar interferometry can be used for the long term monitoring of such sites and to predict potential environmental issues

recent advances in sar interferometry time series analysis for measuring crustal deformation abstract synthetic aperture radar sar interferometry is a technique that permits remote detection of deformation at the earth s surface and has been used extensively to measure displacements associated with earthquakes volcanic activity and many other crustal deformation phenomena analysis of a time series of sar images extends the area where interferometry can be successfully applied and also allows detection of smaller displacements through the reduction of error sources here we review recent advances in time series sar interferometry methods that further improve accuracy this is particularly important when constraining displacements due to processes with low strain rates such as interseismic deformation we include examples of improved algorithms applied to image deformation associated with the 2010 eruption of eyjafjallajokull volcano in iceland slow slip on the guerrero subduction zone in mexico and tectonic deformation in western anatolia turkey

insar measurements of compaction and subsidence in the ganges brahmaputra delta bangladesh many of the world s largest river deltas are sinking due to sediment loading compaction and tectonics but also recently because of groundwater extraction hydrocarbon extraction and reduced aggradation little is known however about the full spatial variability of subsidence rates in complex delta systems this study reconstructs subsidence rates in the eastern portion of the ganges brahmaputra delta gbd bangladesh covering more than 10 000 km2 at a high spatial resolution of 100 m the map was produced using interferometric synthetic aperture radar insar covering the period 2007 to 2011 eighteen advanced land observing satellite phased array l band sar scenes were used to generate 30 interferograms calibrated with gps interferograms were stacked to yield average subsidence rates over the study period small baseline subset insar was then applied to validate the results against an additional gps record from dhaka bangladesh land subsidence of 0 to 10 mm yr is seen in dhaka with variability likely related to local variations in shallow subsurface sediment properties outside of the city rates vary from 0 to 18 mm yr with the lowest rates appearing primarily in pleistocene madhupur clay and the highest rates in holocene organic rich muds results demonstrate that subsidence in this delta is primarily controlled by local stratigraphy with rates varying by more than an order of magnitude depending on lithology the ability of l band insar to differentiate between stratigraphic units in this humid vegetated subtropical river delta demonstrates the power of interferometry as a tool for studying the subsurface in deltaic environments

land subsidence in central mexico detected by alos insar time series abstract massive groundwater extraction is common throughout mexico and is well known to result in land subsidence however most land subsidence surveys focus on one single city mainly mexico city and thus fail to reveal the regional extent of the problem here we use 2007 2011 interferometric synthetic aperture radar insar time series analysis of alos data to resolve land subsidence in the entire central mexico region we identify land subsidence in 21 areas including 17 cities linear vertical rates over 30 cm yr are observed in mexico city while in the other locations rates of 5 10 cm yr are detected we define 3 main categories of subsidence using the averaged velocity maps in conjunction with previously published structural surface geology and land use mapping 1 rapid large scale subsidence 2 rapid local scale subsidence and 3 slow patchy subsidence the correlation between subsidence and land use confirms that groundwater extraction mainly for agricultural and urban activities is the main cause of land subsidence we observe that the boundaries of the subsiding areas are typically characterized by high velocity gradients often coinciding with pre existing faults motion on these faults being driven by water extraction rather than by tectonic activity regional surveys of this type are necessary to understand the spatial and temporal evolution of land subsidence to constrain the distribution and connectivity of water bearing units and ultimately to reach better hazard mitigation plans

time dependent land uplift and subsidence in the santa clara valley california from a large interferometric synthetic aperture radar data set 1 we invert 115 differential interferograms derived from 47 synthetic aperture radar sar scenes for a time dependent deformation signal in the santa clara valley california the time dependent deformation is calculated by performing a linear inversion that solves for the incremental range change between sar scene acquisitions a nonlinear range change signal is extracted from the ers insar data without imposing a model of the expected deformation in the santa clara valley cumulative land uplift is observed during the period from 1992 to 2000 with a maximum uplift of 41 18 mm centered north of sunnyvale uplift is also observed east of san jose seasonal uplift and subsidence dominate west of the silver creek fault near san jose with a maximum peak to trough amplitude of 35 mm the pattern of seasonal versus long term uplift provides constraints on the spatial and temporal characteristics of water bearing units within the aquifer the silver creek fault partitions the uplift behavior of the basin suggesting that it acts as a hydrologic barrier to groundwater flow while no tectonic creep is observed along the fault the development of a low permeability barrier that bisects the alluvium suggests that the fault has been active since the deposition of quaternary units

an examination of seasonal deformation at the portuguese bend landslide southern california using radar interferometry 1 the portuguese bend landslide located on the palos verdes peninsula in southern california is a slow moving landslide whose activity is closely tied to infiltration from rainfall we use radar interferometry to constrain the seasonal kinematics of the landslide from 1995 to 2000 traditional interferometric synthetic aperture radar methods estimate an average downslope displacement rate of 1 00 m yr with an uncertainty range of 0 39 2 57 m yr during the summer months interferograms show a consistent loss in phase coherence over the landslide for epochs greater than 6 months especially in the winter interferograms become incoherent as a result of large displacement and decorrelation is used to map the spatial extent of slide movement through time the displacement rate increases sharply several weeks after the beginning of the rainy season as rainwater percolating into the slide elevates pore pressures phase coherence is lost when the slide velocity surpasses 2 6 m yr for interferograms with durations of a few months a physically based model based on rainfall driven landslide movement incorporates these observations to constrain hydraulic diffusivity to between 0 9 and 3 5 10 6 m2 yr

surface movements in bologna po plain italy detected by multitemporal dinsar abstract we studied the surface deformations affecting the southeastern sector of the po plain sedimentary basin in particular the area of bologna to this aim an advanced dinsar technique referred to as dinsar sbas small baseline subset has been applied this technique allows monitoring the temporal evolution of a deformation phenomenon via the generation of mean deformation velocity maps and displacement time series from a data set of acquired sar images in particular we have processed a set of sar data acquired by the european remote sensing satellite ers sensors and compared the achieved results with optical levelling measurements assumed as reference the surface displacements detected by dinsar sbas from 1992 to 2000 are between 10 mm year in the historical part of bologna town and up to 59 mm year in the ne industrial and agricultural areas former measurements from optical levelling referred to 1897 show 2 3 mm year vertical movements this trend of displacement increased in the second half of the 20th century and the subsidence rate reached 60 mm year we compared the more recent levelling campaigns in 1992 and late 1999 and dinsar results from 1992 to 1999 the standard deviation of the difference between levelling data projected onto the satellite line of sight and dinsar results is 2 mm year this highlights a good agreement between the measurements provided by two different techniques the explanation of soil movements based on interferometric results ground data and geological observations allowed confirming the anthropogenic cause surface effect due to the overexploitation of the aquifers and highlights a natural tectonic subsidence

genesis of selected sandy soils in alberta canada as revealed by microfabric leachate and soil composition micromorphology and lysimeter studies were used to evaluate the nature and formation of the microstructures of some sandy soils in alberta canada the microstructures vary from monic or orthogranic grains uncoated related distribution pattern rdp in the ae horizons to chitonic or chlamydic rdp grains fully or partially coated in the matrix of the b horizons and to porphyric rdp grains embedded in fine mass in the nodules of the b horizons the various genetic transport processes are interpreted to be podzolization including the eluviation of organic matter and organometallic complexes of al and fe lessivage or the mobilization of phyllosilicates particulate fe oxides quartz and feldspar and possibly oxidation reduction processes accountable for the movement of fe2 there are indications in the study that iron oxides like goethite and ferrihydrite are active in the adsorption of organic matter and organo metallic complexes colloidal minerals in the leachates include globular ferrihydrite goethite opal phyllosilicates and very fine quartz chrysophycean stomatocysts and possibly amorphous aluminous materials

quantifying the contribution of multiple factors to land subsidence in the beijing plain china with machine learning technology abstract land subsidence is the ground surface response to underground space development utilization and evolution presently land subsidence has developed into a global comprehensive and interdisciplinary complex systems problem more than half a century has passed since the discovery of subsidence in the beijing plain in the 1960s in this study we investigate the land subsidence in the beijing plain over the period of 2003 2015 using envisat asar and radarsat 2 interferometric datasets and the small baseline subset interferometric synthetic aperture radar sbas insar technique furthermore we introduced the data field model and index based built up index ibi to obtain the dynamic and static load information of the beijing plain then based on a machine learning method we selected the gradient lifting decision tree gbdt model to quantitatively analyze the contributions of groundwater level change compressible deposit thickness and dynamic and static loads to land subsidence the results showed that the maximum land subsidence rate was 122 and 141 mm year in 2003 2010 and 2010 2015 respectively comparisons between the sbas insar results and leveling measurements showed that the minimum absolute error achieved was only 0 2 mm year we suggest that the groundwater exploitation in the third confined aquifer has greater impacts on land subsidence in the beijing plain than the other factors the land subsidence likely occurred in compressible deposit thicknesses exceeding 90 m moreover we found that the compressible thickness and groundwater level contributions to land subsidence exceeded 60 our results provide a scientific basis for the regulation and control of regional land subsidence

surface deformation of long valley caldera and mono basin california investigated with the sbas insar approach abstract we investigate the surface deformation of the eastern california area that includes long valley caldera and mono basin we apply the sar interferometry insar algorithm referred to as small baseline subset sbas approach that allows us to generate mean deformation velocity maps and displacement time series for the investigated area the results presented in this work represent an advancement of previous insar studies of the area that are mostly focused on the deformation affecting the caldera in particular the proposed analysis is based on 21 sar data acquired by the ers 1 2 sensors during the 1992 2000 time interval and demonstrates the capability of the sbas procedure to identify and analyze displacement patterns at different spatial scales for the overall area spanning approximately 5000 km2 two previously unreported localized deformation effects have been detected at paoha island located within the mono lake and in the mcgee creek area within the sierra nevada mountains a zone to the south of the long valley caldera in addition a spatially extended uplift effect which strongly affects the caldera has been identified and analyzed in detail the insar results clearly show that the displacement phenomena affecting the long valley caldera have a maximum in correspondence of the resurgent dome and are characterized by the sequence of three different effects a 1992 1997 uplift background a 1997 1998 unrest phenomenon and a 1998 2000 subsidence phase moreover the analysis of the retrieved displacement time series allows us to map the extent of the zone with a temporal deformation behavior highly correlated with the detected three phases deformation pattern background uplift unrest subsidence we show that the mapped area clearly extends outside the northern part of the caldera slopes accordingly we suggest that future inversion models take this new evidence into account the final discussion is dedicated to a comparison between the retrieved insar measurements and a set of gps and leveling data confirming the validity of the results achieved through the sbas insar analysis

insar time series investigation of long term ground displacement at beijing capital international airport china abstract interferometric synthetic aperture radar insar time series analysis provides high spatial resolution and continuous temporal coverage for investigations of long term ground displacement beijing the capital city of china has suffered from land subsidence since the 1950s and extreme groundwater extraction has led to subsidence rates of 100 mm year in this study insar time series analysis is performed on different data subsets to investigate the ground displacement at capital international airport beijing between june 2003 and november 2013 the results show that the ground surface in the airport has deformed at different rates ranging from 66 2 mm year sinking to 8 2 mm year uplift relative to the reference point the projected vertical displacement rates agreed with measurements estimated from ground leveling surveys and the correlation coefficient of the fitting result is 0 96 with a standard deviation of 0 9 mm year and a mean different of 2 0 mm year the runways and terminals have been affected by land subsidence to various degrees previous studies has indicated that long term intense groundwater extraction is the main reason leading to land subsidence in this area other triggering factors such as active faults the quaternary compressible layers and urbanization also have different degrees of contribution or impact on land subsidence in beijing plain furthermore some interesting behaviors from groundwater such as inter and semi annual variations and subsidence the relationship between them are also found in this study

subsidence induced by urbanisation in the city of rome detected by advanced insar technique and geotechnical investigations abstract we applied the interferometric point target analysis ipta technique to study the city of rome italy aiming to detect and measure the surface movements of buildings and urban structures the available sar dataset has been delivered by esa cat1 3258 and ranges the period 1992 2005 in particular ers1 ers2 data processed covers 1995 2000 while envisat asar 2002 2005 the point target velocity map shows a general stability except for some very local areas affected by subsidence rate larger than 10 mm year the analysis of the time series compared to a detailed geological and geotechnical investigation of the lithostratigraphy of the alluvial sediments of the tiber river and combined with a temporal reconstruction of the expansion of the city over the alluvial valleys allowed us to depict the main factors controlling the observed subsidence these are the in situ effective stress conditions the related compressibility and viscous characteristics of the loaded soils the thickness of the compressible stratum the time since loading instant and the entity of loading furthermore the observed subsidence is time dependent even at a long time scale with respect to the age of the buildings being most of the buildings constructed since the 50s still affected by slow subsidence we mainly focused on the grottaperfetta stream valley that is characterized by an anomalous high and time lasting subsidence original data on the lithostratigraphic setting of this alluvial valley indicate that the high subsidence rate measured up to 2005 is caused by a still active primary consolidation process

volcano tectonic control of merapi s lava dome splitting the november 2013 fracture observed from high resolution terrasar x data abstract volcanism at active andesite dacite volcanoes is often associated with the formation and collapse of circular shaped protrusions of extruded highly viscous lava the so called domes which are emplaced in the near summit region growing domes may experience stable and instable structural phases with a gradual transition in between dome collapse and the break off of instable blocks of viscous lava may lead to pyroclastic flows one of the most lethal hazards at stratovolcanoes at merapi volcano indonesia a new dome started growing in the summit region in the amphitheater formed in the course of the climactic 2010 eruption three years later the dome reached a height of approximately 100 m and diameters of 220 and 190 m with a plateau like surface area of 40 000 m2 approximately on 18 11 2013 an explosion occurred without identified precursors leaving a major fracture cutting the complete dome structure based on high resolution terrasar x satellite radar imagery we could identify the linear fracture traceable over 200 m in the long axis up to 40 m wide after geocoding of the radar amplitude imagery the fractures azimuthal trend could be compared to other structural lineaments indicative of a significant nnw sse structural direction that has formed on merapi volcano in the past the merapi dome fractured in a nw se direction and is consistent with the alignment of regional tectonic structures and of anticipated directions of pyroclastic flows the fracture may be part of a larger volcano tectonic system and may affect the dynamics and the stability of the merapi dome

chrysophycean microfossils in paleolimnological studies abstract the chrysophyceae represent a diverse group of algae with approximately 1000 described species most of which are planktonic and found in oligotrophic lakes a characteristic feature of this class is the endogenous formation of a siliceous resting stage known as a statospore vegetative cells in the family mallomonadaceae are covered by overlapping siliceous scales that are often sculptured and ornamented both the statospores and scales are species specific and because they are siliceous they are usually well preserved in lake sediments this paper reviews the applicability of these microfossils in the interpretation of past lake conditions

3d coseismic deformations and source parameters of the 2010 yushu earthquake china inferred from dinsar and multiple aperture insar measurements abstract the coseismic deformation field related to the 2010 mw6 9 yushu earthquake qinghai china has been investigated by previous studies using the satellite differential interferometric synthetic aperture radar dinsar method however one of the limiting factors in the conventional dinsar is that it can measure only one dimensional 1d ground motion along the radar line of sight los direction thus resulting in anamorphic coseismic displacements and biased source parameters in this paper the three dimensional 3d deformation maps for this earthquake were reconstructed over an area of about 100 70 km2 for the first time by a combined use of the dinsar method for detecting los motion and the multiple aperture interferometry mai method for detecting along track at motion the fault slip map for this earthquake was generated using the 3d deformation maps based on the fault traces on the fault slip map we constructed a fault model with five segments and preformed a two step inversion using the 3d deformation data as the constraint our results show that the maximum coseismic displacements in up down north south and east west directions are 40 4 113 8 and 65 7 cm respectively and the peak to peak slip offset between the southern and northern fault wall is 1 82 m our model reveals a shallow dislocation on a nw se trending fault extending about 74 km along which the four fault segments are nearly vertical 84 88 and the one fault segment dips 66 2 to the southwest the estimated seismic moment is 2 43 1019 nm mw6 92 which is close to the solution provided by the global centroid moment tensor gcmt project the slip distribution derived for each fault patch shows that the slip occurrence extends down to 12 km beneath the ground surface and a peak slip of 2 23 m appears at the depth of about 5 km right near the epicenter comparison with the results derived from the seismic waves field investigation gps and conventional dinsar observations indicates that the source parameters of the yushu earthquake can be improved due to the combined use of dinsar and mai measurements

radarsat 2 d insar for ground displacement in permafrost terrain validation from iqaluit airport baffin island canada abstract the use of differential interferometric synthetic aperture radar d insar is rapidly gaining acceptance as a source of ground displacement information for permafrost regions the accuracy of the information however is still not well established this paper uses a stack of radarsat 2 d insar data to map seasonal ground displacement at the iqaluit airport baffin island canada the accuracy and information content of the d insar products are evaluated with a variety of ground truth data the d insar derived seasonal ground displacement patterns align well with surficial geology units and reflect the thaw settlement characteristics of the sediments they also identify localised displacement patterns in the vicinity of features such as ice wedges and frost cracks comparisons with ground settlement measurements from in situ thaw tubes indicate sub centimetre agreement in dry areas in low lying wet areas however subject to saturation and flooding the d insar stack significantly underestimates the true settlement detecting only 3 7 cm of the 8 5 cm thaw tube measurement the combination of high phase gradients and poor coherence over intermittently flooded surfaces makes it challenging to preserve reliable phase measurements in these areas information from electromagnetic surveys shows that some surface displacement is related to sub surface conditions

land subsidence in china land subsidence in china occurs in different regions it is primarily caused by excessive groundwater withdrawal other reasons for the subsidence include the oil warm groundwater withdrawal and the neotectonic movement the common characteristics of land subsidence in china are slow accumulative irreversible and other unique properties the range of subsidence still keeps extending and the accumulative subsidence increasing though some measures taken adjustment of the aquifer exploitation practice is a subsidiary way to control land subsidence but it cannot solve this problem completely in a specfic way of groundwater changing the contribution of a certain soil layer to the total subsidence depends on its compressibility and thickness besides the elasticity both cohesive soil layers aquitards and sand layers aquifers are observed to be plastic and creep when the groundwater level fluctuates in a specific way which often leads to subsidence delay

lateral podzolization in a sandstone catchment a sandstone catchment of the cool perhumid black forest germany was studied with respect to podzolization processes on a landscape scale soil mapping along a steep slope 25 revealed spodosols with thick e horizons combined with thin spodic horizons in the upper catchment area lowermost parts of the landscape showed thinnest e and thickest bhs horizons this catenary trend was quantified by a non linear increase of the illuviation eluviation ratio of podzolization ierpodzol soil texture pedogenic oxides feo fed alo mnd ph cacl2 corg and mineralogical composition of the clay and medium sand fraction were determined in six representative pedons chemical analysis matched morphology in that very low contents and mass densities of feo fed alo and mnd were found in upslope soils the distal pedons were 2 5 fold higher in these elements the catenary trends corresponded to a downslope increase in ph as well as organic carbon in mineral soils mineralogical analysis showed a decrease in feldspar weathering and an increase in hydroxy interlayered vermiculites towards the downslope soils the morphological chemical and mineralogical results led to the conclusion of a process sequence of i an upslope mobilization and depletion of iron manganese and aluminum e spodosols ii a lateral translocation 30 of catchment discharge occurred as interflow and iii a downslope immobilization resulting in a relative or absolute accumulation of the translocated soil compounds bs spodosols the immobilization probably was controlled by an admixture of fe and base richer rocks into the parent material downslope the concept of lateral podzolization developed in a granite landscape was confirmed in the sandstone area studied

estimating horizontal and vertical movements due to underground mining using alos palsar abstract in this paper the capability of determining the three dimensional 3d ground displacements due to underground mining using the multiple alos palsar interferometric pairs acquired with different viewing geometries has been investigated and validated in the area of west cliff colliery new south wales nsw australia four alos palsar interferometric pairs acquired with two different incidence angles from both ascending and descending orbits were used in this study three different approaches were used to derive the 3d displacement maps the first two approaches utilised sar data only while the third approach required a one dimensional measurement by using other surveying techniques as inputs the results were compared with the gps field survey data obtained between april and may 2008 the obtained results and the gps data agreed well with each other in the vertical and the east west directions however the precision of displacement measured in the north south direction was much poorer for the first two approaches compared to the third approach this was due to two reasons 1 the lack of viewing geometries and 2 the poor temporal overlap in the interferometric combination datasets the results suggested that it is possible to use other one dimensional surveying techniques to assist the insar measurements in order to enhance the accuracy of the 3d deformation derived the horizontal movements in transverse and longitudinal directions were calculated from the 3d deformation results in order to derive the subsidence parameters that have been caused by mining activities the subsidence parameters derived matched well with the gps derived parameters the results suggested that an accurate 3d displacement vectors can be derived by combining insar measurement with measurement from other equipment such as extensometer and optical fibre which may carry out measurement in one direction only ideally north south direction

land subsidence due to groundwater withdrawal in the northern beijing plain china abstract beijing is an international metropolis where over exploration of water resource makes land subsidence becoming more and more serious the related problems cannot be avoided in the coming years because of the giant increase of population the aims of this study are to quantify land subsidence over the period 2003 to 2010 grasp the evolution of the process and investigate the relation with the triggering factors in the northern area of the beijing plain various data including deep compaction from vertical multiple borehole extensometers land subsidence from persistent scatterer interferometry and leveling surveys groundwater levels hydrogeological setting from wellbores and landsat tm image were collected and effectively used to detect the spatial and temporal features of land subsidence and its possible relation with groundwater level changes compressible layer thickness and urban development results show that land subsidence is unevenly distributed and continuously increased from 2003 to 2010 the average loss of elevation over the monitoring period amounted to 92 5 mm with rates up to 52 mm y the distribution of the subsidence bowl is only partially consistent with that of the groundwater depression cone because of the variable thickness of the most compressible fine deposits in fact extensometers reveal that silty clay layers account for the larger contribution to land subsidence with the 15 m thick silty clay layer between 102 and 117 m depth accounting for about 25 of the total subsidence finally no clear correlation has been observed between the subsidence rates and the increase of the load on the land surface connected to the impressive urban development this study represents a first step toward the development of a physically based model of the subsidence occurrence to be used for planning remediation strategies in the northern beijing plain

time series analysis of subsidence associated with rapid urbanization in shanghai china measured with sbas insar method river delta plains deltas are susceptible to subsidence producing undesirable environmental impact and affecting dense population the city of shanghai located in the easternmost of yangtze delta in china is one of the most developed regions in china that experiences the greatest land subsidence excessive groundwater withdrawal is thought to be the primary cause of the land subsidence but rapid urbanization and economic development mass construction of skyscrapers metro lines and highways are also contributing factors in this paper a spatial temporal analysis of the land subsidence in shanghai was performed with the help of the small baseline subset interferometric synthetic aperture radar twenty l band alos palsar images acquired during 2007 2010 were used to produce a linear deformation rate map and to derive time series of ground deformation the results show homogeneous subsidence within the research area but exceptionally rapid subsidence around skyscrapers along metro lines elevated roads and highways was also observed because groundwater exploitation and rapid urbanization responsible for much of the subsidence in the shanghai region are expected to continue future subsidence monitoring is warranted

patterns and mechanisms of coseismic and postseismic slips of the 2011 mw 7 1 van turkey earthquake revealed by multi platform synthetic aperture radar interferometry on 23rd october 2011 a mw 7 1 reverse slip earthquake occurred in the bardakci saray thrust fault zone in the van region eastern turkey earlier geodetic studies have found different slip distributions in terms of both magnitude and pattern in this paper we present several cosmo skymed csk envisat asar and radarsat 2 interferograms spanning different time intervals showing that significant postseismic signals can be observed in the first three days after the mainshock using observations that combine coseismic and postseismic signals is shown to significantly underestimate coseismic slip we hence employed the csk pair with the minimum postseismic signals to generate one conventional interferogram and one along track interferogram for further coseismic modelling our best fit coseismic slip model suggests that 1 this event is associated with a buried nnw dipping fault with a preferable dip angle of 49 and a maximum slip of 6 5 m at a depth of 12 km and 2 two unequal asperities can be observed consistent with previous seismic solutions significant oblique aseismic slip with predominant left lateral slip components above the coseismic rupture zone within the first 3 days after the mainshock is also revealed by a postseismic csk interferogram indicating that the greatest principal stress axis might have rotated due to a significant stress drop during the coseismic rupture

spectral characterization and aster based lithological mapping of an ophiolite complex a case study from neyriz ophiolite sw iran abstract the neyriz ophiolite occurs along the zagros suture zone in sw iran and is part of a 3000 km obduction belt thrusting over the edge of the arabian continent during the late cretaceous this complex typically consists of altered dunites and peridotites layered and massive gabbros sheeted dykes and pillow lavas and a thick sequence of radiolarites reflectance and emittance spectra of neyriz ophiolite rock samples were measured in the laboratory and their spectra were used as endmembers in a spectral feature fitting sff algorithm laboratory spectral reflectance measurements of field samples showed that in the visible through shortwave infrared vnir swir wavelength region the ultramafic and gabbroic rocks are characterized by ferrous iron and fe mg oh spectral features and the pillow lavas and radiolarites are characterized by spectral features of ferric iron and al oh the laboratory spectral emittance spectra also revealed a wide wavelength range of si o spectral features for the ophiolite rock units after continuum removal of the spectra the sff classification method was applied to the vnir swir 9 band stack and to the 11 band data set of swir and tir data sets of the advanced spaceborne thermal emission and reflection radiometer aster sensor using field spectra as training sets for evaluating the potential of these data sets in discriminating ophiolite rock units output results were compared with the geological map of the area and field observations and were assessed by the use of confusion matrices the assessment showed in terms of kappa coefficient that the sff classification method with continuum removal applied to the swir data achieved excellent results which were distinctively better than those obtained using vnir swir data and tir data alone