latest miocene to quaternary horizontal and vertical displacement rates during simultaneous contraction and extension in the southern apennines orogen italy foreland contraction and hinterland extension in the southern apennines orogen of italy produced a complex spatial and temporal pattern of vertical and horizontal displacement remarkably late miocene to mid pleistocene foreland migration of the contractional front at 16 mm yr 1 was not accompanied by uplift and the frontal thrust belt remained at or below sea level only following a mid pleistocene reduction in horizontal displacement did the frontal thrust belt and foreland begin uplift at 0 5 mm yr 1 a rate that increased to 1 mm yr 1 after 125 ka although the extensional hinterland experienced net subsidence during formation of the tyrrhenian basin an extensional transition zone adjacent to the frontal thrust belt records sustained uplift at 0 3 mm yr 1 the interaction of preexisting crustal structure and deep tectonic processes resulted in time integrated displacement rates suggesting steady state deformation for periods of 106 years displacement rate changes were abrupt and occurred over intervals of 105 years or less

the 30 may 1998 spencer south dakota storm part i the structural evolution and environment of the tornadoes abstract on the evening of 30 may 1998 atmospheric conditions across southeastern south dakota led to the development of organized moist convection including several supercells one such supercell was tracked by both a weather surveillance radar 1988 doppler wsr 88d from sioux falls south dakota kfsd and by a doppler on wheels dow mobile radar this supercell remained isolated for an hour and a half before being overtaken by a developing squall line during this time period the supercell produced at least one strong and one violent tornado the latter of which passed through spencer south dakota despite the absence of strong low level environmental wind shear the two tornadoes were observed both visually and with the dow radar at ranges between 1 7 and 12 9 km the close proximity to the tornadoes permitted the dow radar to observe tornado scale structures on the order of 35 to 100 m while the nearest wsr 88d only resolved the parent mesocyclone in the supercell the dow observations revealed

seismic evidence of longitudinal extension in the southern apennines chain italy the 1997 1998 sannio matese seismic sequence 1 we present evidence of longitudinal extension in the apennines based on data from the 1997 1998 sannio matese seismic sequence the earthquakes occurred between the nw se faults responsible for larger historical earthquakes inversion of focal mechanisms indicates a stress field with a prevailing normal stress characterized by a nnw sse sub horizontal 3 this stress regime is consistent with normal movements along ne sw faults these features suggest that the ne sw faults located in between the nw se faults cannot be interpreted as transfer faults or old faults reactivated during the eastward migration of the chain we propose that the deformation due to the eastward chain migration concentrates along nw se normal faults which are responsible for the largest earthquakes whereas the deformation related to the chain curvature concentrates along ne sw normal faults which are responsible for the lower energy seismic sequences

linear iterative refinement method for the rapid simulation of borehole nuclear measurements part i vertical wells as a result of its high numerical accuracy and versatility to include complex tool configurations and arbitrary spatial distributions of material properties the monte carlo method is the foremost numerical technique used to simulate borehole nuclear measurements although recent advances in computer technology have considerably reduced the computer time required by monte carlo simulations of borehole nuclear measurements the efficiency of the method is still not sufficient for estimation of layer by layer properties or combined quantitative interpretation with other borehole measurements we develop and successfully test a new linear iterative refinement method to simulate nuclear borehole measurements accurately and rapidly the approximation stems from monte carlo derived geometric response factors referred to as flux sensitivity functions fsfs for specific density and neutron tool configurations our procedure first invokes the integral representation of boltzmann s transport equation to describe

the displacement field of the landers earthquake mapped by radar interferometry geodetic data obtained by ground or space based techniques can be used to infer the distribution of slip on a fault that has ruptured in an earthquake although most geodetic techniques require a surveyed network to be in place before the earthquake1 3 satellite images when collected at regular intervals can capture co seismic displacements without advance knowledge of the earthquake s location synthetic aperture radar sar interferometry first introduced4 in 1974 for topographic mapping5 8 can also be used to detect changes in the ground surface by removing the signal from the topography9 10 here we use sar interferometry to capture the movements produced by the 1992 earthquake in landers california11 we construct an interferogram by combining topographic information with sar images obtained by the ers 1 satellite before and after the earthquake the observed changes in range from the ground surface to the satellite agree well with the slip measured in the field with the displacements measured by surveying and with the results of an elastic dislocation model as a geodetic tool the sar interferogram provides a denser spatial sampling 100 m per pixel than surveying methods1 3 and a better precision 3 cm than previous space imaging techniques12 13

permanent scatterers for landslide investigations outcomes from the esa slam project within the slam project service for landslide monitoring launched in 2003 by the european space agency esa the permanent scatterers ps technique a multi image interferometric approach coupled with the interpretation of aerial photos and optical satellite images was carried out for landslide investigations the ps analysis was applied at a regional scale as support for landslide inventory mapping and at local scale for the monitoring of single well known slope movements for the integration of the ps measurements within a landslide inventory the arno river basin italy was chosen as test site for the presence of a high number of mass movements to date about 300 areas at high landslide risk and more than 27 000 individual landslides mapped by the institutional authorities about 350 sar images have been interferometrically processed by means of the ps technique with the detection of about 600 000 ps the use of optical images contributed spatial meaning to the point wise information provided by the ps making it easier to identify terrain features related to slope instability and the landslide boundaries here we describe the employed methodology and its impact in the updating of a preexisting landslide inventory 6 8 of the total number of landslides were characterized by ground displacement measurements from the ps 6 1 of already mapped landslides and 0 8 of new unstable areas detected through the ps analysis moreover most of the ps are located in urban areas showing that the proposed methodology is suitable for landslide mapping in areas with a quite high density of urbanization but that over vegetated areas it still suffers from the limitations induced by the current space borne sar missions e g temporal de correlation on the other hand the use of insar for the monitoring of single slow landslides threatening built up areas has provided satisfactory results allowing the measurement of superficial deformations with high accuracy on the landslide sectors characterized by a good radar reflectivity and coherence

ground deformation monitoring by using the permanent scatterers technique the example of the oltrepo pavese lombardia italy abstract the applicability of the permanent scatterers synthetic aperture radar interferometry psinsar technique for detecting and monitoring ground displacements was tested in the oltrepo pavese territory northern italy southern lombardia which could be representative of similar geological contexts in the italian apennines the study area which extends for almost 1100 km 2 is characterized by a complex geological and structural setting and the presence of clay rich sedimentary formations these characteristics make the oltrepo pavese particularly prone to several geological hazards shallow and deep landslides subsidence and swelling shrinkage of the clayey soils the psinsar technique used in this study overcomes most of the limitations of conventional interferometric approaches by identifying within the area of interest a set of radar benchmarks ps where very precise displacement measurements can be carried out more than 90 000 ps were identified by processing synthetic aperture radar sar images acquired from 1992 to 2001 by the european remote sensing satellites ers the psinsar application at a sub regional scale detected slow ground deformations ranging from 5 to 16 mm year and resulting from various processes landslides swelling shrinkage of clay soils and water pumping the ps displacements were analysed by collecting data obtained through geological geomorphologic field surveys geotechnical analysis of the soils and the information was integrated within a landslide inventory and the damaged building inventory despite the limited number of landslide bodies with ps 7 of the inventoried landslides the ps data helped to revise the state of activity of several landslides furthermore some previously unknown unstable slopes were detected two areas of uplift and two areas of subsidence were identified

cyclical slope instability and volcanism related to volcano tectonism in resurgent calderas the ischia island italy case study abstract the results of a detailed stratigraphic study carried out in the areas located to the east and south west of mt epomeo at ischia are presented and compared with those of previous geological archaeological and historical investigations to show the relationships among caldera resurgence volcanism and slope instability in the past 5 5 ka resurgence at ischia began at about 30 ka b p and occurred through intermittent uplifting and tectonic quietness phases during the past 5 5 ka reactivation of faults and related volcanic activity was accompanied by emplacement of deposits generated by surface gravitational movements these deposits were generated in four main phases dated between 5 5 and 2 9 ka around 2 9 ka between 2 6 and 2 3 ka and between 2 3 and 1 9 ka respectively deposits formed by gravitational movements preceded and followed the emplacement of volcanic rocks testifying that slope instability was induced by vertical movements which also activated and or reactivated faults and fractures that fed volcanism the results of this study therefore suggest that although slope failure can occur as a consequence of a variety of factors resurgence has to be considered a factor inducing a particularly intense slope instability resurgence is accompanied by activation of faults and renewal of volcanism causing oversteepening of the slopes and generating seismicity that could trigger surface gravitational movements furthermore the availability of large amount of loose material rapidly accumulated along the slopes during eruptions favors landslide generation

a proposal for the kinematic modelling of w dipping subductions possible applications to the tyrrhenian apennines system in w dipping subduction zones there is a general eastward progression of the back arc basin accretionary wedge foredeep complex with the forward progression early stages of the complex are revealed by slices of upper crust and sedimentary cover abandoned to the west left floating above a new section of mantle a major shear zone should form at the new moho separating upper crust slices of earlier accretionary stages and the eastward flowing mantle the mantle wedging at the top of the subduction plane could be responsible for the uplift of the central parts of the belt the retreating of the subduction hinge is interpreted as due to the push generated by the eastward mantle flow detected in the hot spot reference frame the foredeep depth is mainly a function of the radius of curvature of the subduction hinge the frontal wedge is constructed from the stacking of the upper layers of the subducting plate and the syntectonic clastics that fill the foredeep which are progressively involved in thrusting and later by extension in order to preserve volume balance the lithosphere of the eastern plate before subduction has to be the same size as that which has been subducted due to the longer length of the arc with respect to the original length of the linear margin between the two converging plates laterally stretched subducted lithosphere is predicted at depth w dipping subductions usually have a short life probably due to their inherent capability to produce new lateral heterogeneities of the lithosphere the thin back arc which are a key factor in controlling and generating new subductions both e and w dipping this model is applied to the apennines tyrrhenian sea system

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

slope movements in a dynamic environment a case study of tachia river central taiwan abstract it is well established that landslides are extensively triggered as a result of large seismic events in upland areas some authors have postulated that sediment moves through the drainage system as a slug whilst others have noticed only limited impact as material remains stored in the drainage basin what has almost never been addressed is the continued evolution of the landslides themselves after the seismic event and their continued role in releasing slope materials this paper examines the tachia river basin in western taiwan which was extensively affected by landslides during the 1999 chi chi earthquake using vertical cartographic aerial photographs and satellite images this study demonstrates that the area affected by landslides increased substantially after the main earthquake as a result of high intensity rainfall events analysis of suspended sediment data from downstream of the area affected by landslides show that sediment concentration steadily increases with time in the period after the initialization of slope movements a model in which sediment production increases immediately after the earthquake and then steadily reduces through time appears to be over simplistic and should be replaced by a model that incorporates complex responses to the initial and subsequent events

evaluation of recent glacier recession in the cordillera blanca peru ad 1962 1999 spatial distribution of mass loss and climatic forcing we use a combination of aerial photogrammetry satellite imagery andd ifferential gps mapping to quantify the volume of ice lost between ad 1962 and 1999 from three glaciers on nevado queshque in the cordillera blanca peru 101s the largest averagedsurface lowering thinning occurredin the southwest aspect 22 m andthe least in the eastern aspect 5 m a heuristic sensitivity analysis indicates that 9 3 w m 2 was requiredto melt the total observedice loss andthis can be explainedby sensible heat transfer relatedto a temperature rise of 1 1c combinedwith a latent heat d ecrease relatedto a 0 14 g kg 1 increase in specific humidity a first difference analysis of temperature records from 29 stations in the cordillera blanca shows an average rising trend of 0 261c per decade over the 37 year interval more than adequate to supply the hypothesized sensible heat transfer a simple transmittivity model within a digital elevation model indicates solar radiation related to altered cloudiness was not a predominant climatic forcing the distribution of glacier area with altitude calculated with the digital terrain model explains the observed asymmetrical ice melt r 2005 elsevier ltd all rights reserved

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

large scale longitudinal extension in the southern apennines contractional belt italy during late cenozoic thrusting the interior of the peri tyrrhenian orogenic belt in the southern apennines underwent two episodes of nearly orthogonal extension early extension was oriented subparallel to the axis of the tectonic belt and formed in response to progressive thrust belt arcuation the length of the tectonic belt increased by 50 and the longitudinal strain was accommodated by low angle normal faults concentrated in tectonic domains recording up to 150 200 extension younger extension oriented at a high angle to the orogen was accompanied by pliocene pleistocene uplift and by southeasterly migration of tyrrhenian sea rifting

rheological behaviour of the crust in southern apennine italy results from a thermal and seismological study to add information on the brittle ductile transition of the southern apennine we investigated a rheological profile of the crust along a wsw ene oriented cross section running from neapolitan volcanic zone to apulia foreland the rheological model was obtained computing a thermal modelling and constrained by a relocalization of earthquakes of the area results show that the area is characterized by horizontal rheological variations with two horizons interlayered with ductile horizons that are quite predominant with respect to vertical ones the horizontal stratification of lithospheric rheology has important geodynamic consequence and could provide new insights to better understand the tectonic processes which have played a major role to construct the southern apennine belt results of this study suggested that well constrained rheological models built integrating information from both relocated earthquakes and thermal state could give important hints on the mechanical behaviour of the crust and its related tectonic processes

effect of improper water and land resource utilization on the central main ethiopian rift lakes the ethiopian rift is characterized by a chain of lakes varying in size hydrological and hydrogeological setting some of the lakes and tributary rivers are used for irrigation soda abstraction commercial fish farming and recreation and they support a wide variety of endemic birds and wild animals few lakes shrunk due to excessive abstraction of water others expanded due to increase in surface runoff and groundwater flux from percolated irrigation water excessive land degradation deforestation and over irrigation resulted in sedimentation in lakes and increase in soil salinity the chemistry of some of the lakes has also been changed dramatically this paper addresses the major environmental changes in the last few decades in the central main ethiopian rift lakes that resulted mainly from anthropogenic factors the methods employed include field hydrogeological mapping supported by aerial photograph and satellite imagery interpretations hydro meteorological data analysis water balance estimation catchment hydrological and groundwater flow modelling and hydrochemical analysis a converging evidence or integrated approach has been adapted to reconstruct the temporal and spatial variations of lake levels and hydrochemistry the result revealed that the major changes in the rift valley are related mainly to recent improper utilization of water and land resources in the lakes catchment and direct lake water abstraction aggravated intermittently by climatic changes the terminal lakes show dramatic reduction in level and increase in salinity these changes appear to have grave environmental consequences on the fragile rift ecosystem which demands extremely urgent integrated basin wide water management practice

resolving vertical tectonics in the san francisco bay area from permanent scatterer insar and gps analysis using a combination of gps measured horizontal velocities of 200 sites and 115 487 range change rates determined with the permanent scatterer interferometric synthetic aperture radar insar method in the san francisco bay area we resolve vertical motions in the region at sub mm yr precision the highest displacement rates are due to nontectonic processes such as active landslides subsidence and rebound over aquifers and rapid settling of unconsolidated sediments along the bay margins residual displacement rates are determined by removing the contribution of the gps derived horizontal velocity field from the insar range change rates to isolate vertical tectonic rates we use only those insar measurements made on material that was not quaternary substrate which is susceptible to nontectonic and seasonally varying ground motions the insar residuals indicate significant uplift over the southern foothills of the active mount diablo anticlinorium the mission hills stepover region of the hayward and calaveras faults and the central and southern santa cruz mountains located along a restraining bend of the san andreas fault

space geodesy subsidence and flooding in new orleans a subsidence map of the city offers insight into the failure of the levees during hurricane katrina

two examples of the use of sar interferometry on displacement fields of small spatial extent interferometric combination of pairs of sar images acquired by the european ers 1 satellite maps deformation fields associated with two phenomena both of small spatial extension and located in se france the one is rapid terrain deformation caused by a landslide near the city of saint etienne de tinee and the other is slower subsidence caused by underground coal mining near gardanne unlike interferometric measurement of wide field deformation atmospheric propagation heterogeneity is not an accuracy limiting factor although the radar data confirm prior knowledge concerning the landslide such an application of sar interferometry appears difficult under normal conditions of observation using current spaceborne radar systems the study of soil subsidence however can be generalized and improves prior knowledge of the displacement field which has here been modeled assuming elastic deformation in a half space from several sources the two examples help to understand the limits of the interferometric technique

dynamics of slow moving landslides from permanent scatterer analysis high resolution interferometric synthetic aperture radar insar permanent scatterer data allow us to resolve the rates and variations in the rates of slow moving landslides satellite to ground distances range changes on landslides increase at rates of 5 to 7 millimeters per year indicating average downslope sliding velocities from 27 to 38 millimeters per year time series analysis shows that displacement occurs mainly during the high precipitation season during the 1997 1998 el nino event rates of range change increased to as much as 11 millimeters per year the observed nonlinear relationship of creep and precipitation rates suggests that increased pore fluid pressures within the shallow subsurface may initiate and accelerate these features changes in the slope of a hill resulting from increases in the pore pressure and lithostatic stress gradients may then lead to landslides

seismic study of the 41st parallel fault system offshore the campanian latial continental margin italy abstract a set of seismic reflection lines collected in the southern tyrrhenian sea offshore the campanian latial continental margin has been selected and interpreted the aim is to characterize 1 the structural features of the 41st parallel line 41pl an e w elongated magnetic anomaly zone separating the northern tyrrhenian domain from the southern tyrrhenian domain and 2 to study the relationships between the 41pl and the ortona roccamonfina line orl a tectonic structure transversal to the apennines along which the northern apennine arc merges the southern arc the interpretation of the seismic lines is discussed in light of the available geological stratigraphic and structural and geophysical gravimetric and magnetic information results show that the campanian latial continental margin is characterized by a series of structural lows and highs that match with the main structures on the mainland mt massico horst the volturno and garigliano depressions the study area is characterized by ese wnw to e w and ne sw striking faults the activity of these faults developed during pliocene early pleistocene times ese wnw to e w faults display structures consistent with strike slip movements these faults which are located on the maximum gradient of the e w elongated magnetic alignment of 41pl are responsible for the sse translation of the offshore sector of the mt massico horst the horizontal dislocation of mt massico suggests left lateral movements for the ese wnw to e w faults the ne sw faults that affect the mt massico horst which represents the southern tip of orl show seismic features consistent with normal movements as also revealed by inland data since 1 background seismicity is virtually absent along the study area and 2 the uppermost seismic reflectors seem unaffected by faults it is very likely that both the orl and 41pl fault zones are now inactive at least in the campanian latial area seismic data indicate that orl is older than 41pl and support the interpretation that the 41pl represents a deep seated transfer fault system formed in response to the different rates of opening of the tyrrhenian sea the strike slip movements along the 41pl faults and the normal movements along the orl faults are consistent with a nw se extension which is responsible for the longitudinal extension in the southern apennines belt

gravity and magma induced spreading of mount etna volcano revealed by satellite radar interferometry 1 mount etna underwent a cycle of eruptive activity over the past ten years here we compute ground displacement maps and deformation time series from more than 400 radar interferograms to reveal mount etna s average and time varying surface deformation from 1992 to 2001 we find that during this time interval it experienced magmatic inflation and radial spreading to the west south and east steady relative motion between the west and south flanks and between the east and north flanks during this time interval suggests they are related to gravitational spreading of the volcanic edifice time series analysis shows that growth of a southeastern basal anticline began with the end of magma recharge in 1995 thus showing a direct link between deep seated magma intrusions and edifice spreading these observations support a complex mode of radial gravitational collapse underlain by deeper magma driven basal spreading although ultimately the two must be related

modelling gravity variations consistent with ground deformation in the campi flegrei caldera italy abstract in recent years 1970 72 and 1982 84 two inflation episodes took place in the campi flegrei caldera italy characterized by significant ground uplift and gravity variations an elastic half space model with vertical density stratification is employed to compute the displacement field and the gravity variations produced by the deformation of buried layers following the inflation of a spherically symmetric deformation source contributions to gravity variations are produced by dilation contraction of the medium by the displacements of density interfaces the free surface and subsurface layers and of source boundaries and possibly by new mass input from remote distances into the source volume three cases were examined in detail in case i the magma chamber is identified as the deformation source and volume and pressure increase in the magma chamber is due to input of new magma from remote distances in case ii deformation is due to magma differentiation within the magma chamber deformation source with constant mass in case iii the geothermal system is identified as the deformation source and a pressure increase possibly driven by the exsolution of high temperature and high pressure volatiles in the magma chamber is assumed to play a dominant role from the comparison between measured and computed gravity residuals free air corrected gravity variations we can assess that in case i an inflation source with constant density would predict gravity residuals compatible with observations whereas an expansion at constant mass case ii would predict gravity residuals much lower than observed the resolving power of gravity data however prevents accurate assessment of the density of the emplaced material in case iii the pervasive density increase of the geothermal fluids induced by pressure increase is assumed to be the main source of gravity variations the average porosity value required for this model to match both the ground deformation and the gravity residuals is found to be 10 a value which is compatible with measured porosity values at campi flegrei in deep wells the subsidence phases following both inflation episodes and the gravity residuals during subsidence lead us to consider case iii as more plausible even if a suitable combination of cases i and iii cannot be discarded

quantitative interpretation of pulsed neutron capture logs part 1 fast numerical simulation pulsed neutron capture pnc logs are commonly used for formation evaluation behind casing and to assess time lapse variations of hydrocarbon pore volume because conventional interpretation methods for logs assume homogeneous formations errors may arise especially in thinly bedded formations when appraising petrophysical properties of hydrocarbon bearing beds there exist no quantitative interpretation methods to account for shoulder bed effects on logs acquired in sand shale laminated reservoirs because of diffusion effects between dissimilar beds logs acquired in such formations do not obey mixing laws between the responses of pure sand and pure shale end members of the sedimentary sequence we have developed a new numerical method to simulate pnc rapidly and accurately logs the method makes use of late time thermal neutron flux sensitivity functions fsfs to describe the contribution of multilayer formations toward the measured capture cross section it includes a correction procedure

quantitative interpretation of pulsed neutron capture logs part 2 inversion of measurements in thinly bedded formations we have developed an inversion method to reduce shoulder bed effects on pulsed neutron capture pnc logs for estimating layer by layer capture cross sections the method is based on a previously developed rapid approximation of pnc logs tests performed on synthetic examples that include a variety of lithology saturating fluid and bed thickness configurations confirm the efficiency reliability and stability of the inversion procedure inversion consistently improves the vertical resolution and definition of pnc logs across beds thinner than 45 cm our fast iterative algorithm inverts logs in seconds of cpu time and is therefore suitable for joint petrophysical interpretation with other open and cased hole logs

investigating landslides with space borne synthetic aperture radar sar interferometry abstract this paper is addressed to readers without advanced knowledge of remote sensing it illustrates some current and potential uses of satellite synthetic aperture radar interferometry insar for landslide assessment data acquired by sar systems can provide 3d terrain models and be used to assist in regional scale investigations e g aimed at evaluation of susceptibility of slopes to failure under favourable environmental conditions the innovative permanent scatterers ps technique which overcomes several limitations of conventional sar differential interferometry dinsar applications in landslide studies is suitable for monitoring slope deformations with millimetric precision the ps technique combines the wide area coverage typical of satellite imagery with the capability of providing displacement data relative to individual image pixels with the currently available radar satellites however only very slow ground surface displacements can be reliably detected and measured the presented case study of a landslide from the liechtenstein alps indicates that the most attractive and reliable contribution provided by this remote sensing technique lies in the possibility of i wide area qualitative distinction between stable and unstable areas and ii qualitative relative hazard zonation of large slow landslides based on the identification of segments characterised by different movement rates since only the radar line of sight projection of the displacements can be detected a quantitative exploitation of the ps data is possible only where sufficient ground truth is available in site specific or single landslide investigations the ps data can represent a very useful complementary data source with respect to the information acquired through ground based observations and in situ surveying however the difficulties associated with the feasibility assessments of the applicability of sar data to local scale problems as well as with the interpretation of ps results require a close collaboration between landslide experts and specialists in advanced processing of radar satellite data the interpretation of the exact geotechnical significance of small radar sensed ground surface deformations is challenging especially where ground truth is lacking although any ground deformation is potentially of interest to an engineering geologist detection of movements in both vertical and horizontal directions is needed in the case of landslides to evaluate slope failure mechanisms with their high radar viewing angles however the current space borne systems can detect only a fraction of the horizontal component of movement it is expected that the upcoming sar dedicated missions with new sensors and different acquisition geometries combined with the rapid developments in the field of advanced radar data processing will allow a full 3d reconstruction of deformation data and help to further reduce the current limitations of the ps and similar dinsar approaches

urban subsidence inside the city of napoli italy observed by satellite radar interferometry satellite radar interferometry reveals subsidence occurring in an area of about 2 km by 2 km inside the city of napoli italy the observations show a maximum vertical displacement of about 5 cm between 1992 93 and 1996 while the deformation signal decreases between 1996 and 1998 the investigated area is densely populated and has been influenced between 1992 and 1995 by intensive construction of a new underground railway these interferometric results demonstrate the high correlation between the observed deformation and the excavation of the tunnels for the development of the underground

observation and modelling of the saint etienne de tinee landslide using sar interferometry abstract six different interferograms of the la clapiere landslide were derived from ers 1 sar images during the period aug 20 sept 4 1991 the coherence of the associated images is shown to remain significant over most of the surface of the landslide during the two weeks of the survey the interferograms are remarkably similar and indicate steady state displacements over at least 12 days the displacement field derived from the interferograms is shown to be characterized by a non uniform displacement gradient from top to bottom and reveals a significantly faster motion of the western part of the landslide the amplitude of the motion deduced from interferometry is shown to be in good agreement with ground measurements finally sar interferometry is shown to be able to evidence small scale instabilities which may not be observed with discrete ground measurements

constraints on the seismotectonics of the central mediterranean from very long baseline interferometry summary very long baseline interferometry vlbi determined site velocities from seven stations in western europe reveal a stable continental platform north of the alps deformations between sweden germany and spain can not exceed 2 mm yr south of the alps significant motions are occurring with respect to stable europe two sites east of the apennine mountains on peninsular italy have north easttrending velocities which increase from 2 mm yr l in the north at medicina to 6 mm yr l in the south at matera in contrast the vlbi site in the south eastern corner of sicily is moving 7 mm yr i to the north north west these velocities are largely explained if southern sicily is attached to a north westerly moving african plate and the eastern portion of the italian peninsula forms part of a hypothesized adriatic sea crustal block which is rotating counter clockwise with respect to europe about a pole near the alps such an explanation is consistent with the styles of the larger historical earthquakes of the region which show ne sw extension across the apennines north south convergence across the alps and ne sw compression in coastal yugoslavia the adria plate model generates 1 5 2 2 x 10l8 nm yr l of potential earthquake moment along the northern and central apennines historical records suggest that 30 60 per cent of this moment is released seismically based on a direct strain rate measurement recurrence intervals for italian earthquakes south of medicina are estimated to be 12 46 yr for m6 5 quakes and 35 143 years for m7 0 quakes

subsidence due to crack closure and depressurization of hydrothermal systems a case study from mt epomeo ischia island italy levelling surveys carried out between 1990 and 2003 on the mt epomeo resurgent block ischia island record negative dislocations on its northern and southern flanks with a maximum subsidence rate of 1 27 cm yr 1 this deformation is not associated with the cooling crystallization or lateral drainage of magma and cannot be explained by a pressure point or prolate ellipsoid source results from dislocation models and the available structural and geochemical information indicate that the subsidence is due to crack closure processes along two main ene wsw and e w preexisting faults which represent the preferred pathway of co2 degassing from the hydrothermal system located beneath mt epomeo the monitoring of the dislocations and co2 flux along these faults could give useful information on the dynamics of the hydrothermal system

geodetic strain in peninsular italy between 1875 and 2001 1 we determine geodetic strain in peninsular italy by the gps reoccupation of the first order triangulation network of italy installed from 1860 the uncertainties in the original measurements about 3 ppm and the time span between the two observations imply that tectonic signals larger than about 0 03 ppm yr are resolvable along the apenninic belt where the largest earthquakes are concentrated the geodetic deformation has a clear and consistent strain pattern between adjacent regions well above the uncertainties and shows a pervasive ne sw extension along the tyrrhenian and adriatic coasts the geodetic signal is not homogeneous and is comparable with the uncertainty in the original measurements seismic deformation calculated over the same time interval agrees well with estimated extensional direction but the magnitudes of geodetic and seismic strain differ suggesting that in part of the apennines significant strain accumulation over the past 130 years may not have been released in earthquakes

ground deformation due to tectonic hydrothermal gravity hydrogeological and anthropic processes in the campania region southern italy from permanent scatterers synthetic aperture radar interferometry abstract we apply the permanent scatterers synthetic aperture radar interferometry ps insar technique to the campania region southern italy which includes the southern apennines chain and plio quaternary structural depressions with the aim to detect ground displacements at a regional scale the study area which extends for 13 600 km 2 is characterized by intense urbanization active volcanoes phlegraean fields vesuvius and ischia seismogenic structures landslides hydrogeological instability ps insar technique allows us to identify a set of radar benchmarks ps where accurate displacement measurements can be carried out about 1 7 10 6 ps are identified by processing synthetic aperture radar sar images acquired in ascending and descending orbits from 1992 to 2001 by the european remote sensing satellites ers the ps insar application at regional scale detected ground deformations ranging from 28 to 39 mm yr the calculated velocity values are consistent with the available gps and levelling data from selected areas we identify volcanic areas in which the deformation is mainly related to the depressurization of the local hydrothermal systems and recognize deformations along seismogenic and aseismic nnw sse and nw se faults the deformations localized along the southern apennines chain are mainly related to landslides while those occurring in the plains are due to subsidence processes induced by intensive drainage from wells i e anthropic activity the review of 9 years of sar data shows that tectonic volcanic hydrothermal gravity and anthropic processes are responsible for the ground deformation of campania the proposed joint interpretation of deformation fields related to natural and anthopogenic factors provides a comprehensive view of the dynamics of the earth s surface