crustal structure evolution and volcanic unrest of the alban hills central italy the alban hills a quaternary volcanic center lying west of the central apennines 15 25 km southeast of rome last erupted 19 ka and has produced approximately 290 km3 of eruptive deposits since the inception of volcanism at 580 ka earthquakes of moderate intensity have been generated there at least since the roman age modern observations show that intermittent periods of swarm activity originate primarily beneath the youngest features the phreatomagmatic craters on the west side of the volcano results from seismic tomography allow identification of a low velocity region perhaps still hot or partially molten more than 6 km beneath the youngest craters and a high velocity region probably a solidified magma body beneath the older central volcanic construct thirty centimeters of uplift measured by releveling supports the contention that high levels of seismicity during the 1980s and 1990s resulted from accumulation of magma beneath these craters the volume of magma accumulation and the amount of maximum uplift was probably at least 40 106 m3 and 40 cm respectively comparison of newer levelings with those completed in 1891 and 1927 suggests earlier episodes of uplift the magma chamber beneath the western alban hills is probably responsible for much of the past 200 ka of eruptive activity is still receiving intermittent batches of magma and is therefore continuing to generate modest levels of volcanic unrest bending of overburden is the most likely cause of the persistent earthquakes which generally have hypocenters above the 6 km deep top of the magma reservoir in this view the most recent uplift and seismicity are probably characteristic and not precursors of more intense activity

improving understanding of near term barrier island evolution through multi decadal assessment of morphologic change abstract observed morphodynamic changes over multiple decades were coupled with storm driven run up characteristics at fire island new york to explore the influence of wave processes relative to the impacts of other coastal change drivers on the near term evolution of the barrier island historical topography was generated from digital stereo photogrammetry and compared with more recent lidar surveys to quantify near term decadal morphodynamic changes to the beach and primary dune system between the years 1969 1999 and 2009 notably increased profile volumes were observed along the entirety of the island in 1999 and likely provide the eolian source for the steady dune crest progradation observed over the relatively quiescent decade that followed persistent patterns of erosion and accretion over 10 30 and 40 year intervals are attributable to variations in island morphology human activity and variations in offshore bathymetry and island orientation that influence the wave energy reaching the coast areas of documented long term historical inlet formation and extensive bayside marsh development show substantial landward translation of the dune beach profile over the near term period of this study correlations among areas predicted to overwash observed elevation changes of the dune crestline and observed instances of overwash in undeveloped segments of the barrier island verify that overwash locations can be accurately predicted in undeveloped segments of coast in fact an assessment of 2012 aerial imagery collected after hurricane sandy confirms that overwash occurred at the majority of near term locations persistently predicted to overwash in addition to the storm wave climate factors related to variations within the geologic framework which in turn influence island orientation offshore slope and sediment supply impact island behavior on near term timescales

geohazards monitoring in roma from insar and in situ data outcomes of the pangeo project within the pangeo project financed by the european commission under the 7th framework program the geological survey of italy ispra and the urban planning department of the city of roma developed a geodatabase and map of the geological hazards for the territory of roma integrating remotely sensed data psinsar permanent scatterer interferometry synthetic aperture radar and in situ geological information numerous thematic layers maps and inventories of hazards e g landslides sinkholes cavities geological and hydrogeological data added to historical and recent urbanization information were compared to the permanent scatterer ps data from the european remote sensing satellites ers 1 2 1992 2000 and envisat 2002 2005 descending scenes in order to produce a ground stability layer gsl based on the ps data most of the territory appears stable almost 70 of ps velocities are within 1 mm year about 14 of the pss show positive line of sight los velocities measured along the los of the satellite between 1 and 3 mm year and more than 2 exceed 3 mm year more than 11 of pss show negative los velocities between 1 and 3 mm year while about 3 exceed 3 mm year with tens of the pss showing velocities over 20 mm year the gsl is comprised of polygons or multi polygons multipart polygons grouping individual polygons under a single identifier geohazard enclosing areas where geohazards have been pointed out by ps data and or in situ surveys observed instabilities and by polygons enclosing areas potentially affected by geohazards based on the available knowledge of the territory potential instabilities in roma s gsl 18 multi polygons covering ca 600 km2 related to observed instabilities have been outlined where ground movements could be detected through insar data or where landslides and sinkholes are known to have occurred other 13 multi polygons covering nearly 900 km2 concern areas where the potential occurrence of geohazards was inferred by combining geological and or geothematic data potential instabilities the geohazards mapped in roma have been landslides collapsible grounds compressible grounds groundwater abstraction mining man made ground tectonic movements and volcanic inflation deflation the lattermost is the likely cause of the significant uplift observed in the alban hills area however this paper focuses on two more currently impending hazards subsidence and sinkholes in general sinkhole prone areas areas of dense underground cavities are hard to discern from satellite data but can be revealed by ruling out other potential causes of observed ground movement based on in situ data subsiding zones are effectively detected by the available psinsar dataset over a total extent of about 60 km2 mostly overlapping the recent alluvial areas of the tiber and its tributaries pss show a very different behaviour inside and outside the historical centre inside loading by anthropogenic construction and man made ground since ancient times has led to an almost complete consolidation of the recent river deposits marked by modest to absent subsidence in contrast outside subsidence clearly stands out with negative los velocities that although generally within several mm year can locally exceed 25 mm year ps data have provided motion information at both a regional and local scale up to the scale of a single building closer to the sea in the tiber delta area velocities increase especially above recently reclaimed marsh areas rich in peat and organic clays velocities can change significantly over short distances as in the international airport area reflecting the local stratigraphic setting the same occurs in the two subsiding areas located within the alban hills volcanic complex which is generally affected by ground uplift as a whole psinsar ground motion velocities offer a significant contribution to susceptibility and hazard recognition studies in particular such a method provides a fast and effective tool available to local authorities to monitor ground and building behaviour possibly allowing for timely prevention activities especially when coupled with appropriate in situ knowledge

detecting and monitoring of landslides using persistent scattering synthetic aperture radar interferometry persistent scatterer synthetic aperture radar interferometry psinsar is an applied time series technique to overcome limitations of insar temporal and geometrical decorrelation and atmospheric delay anomalies for monitoring of ground surface deformations this method only monitors displacements on pixels with nearly constant temporal backscattering characteristics in this study datasets of ascending alos palsar l band images recorded from 2006 to 2010 and descending envisat asar c band images acquisitioned between 2003 and 2010 were processed to detect and monitor the landslide occurred in the noghol area iran application of the psinsar technique on both palsar and asar images has significantly improved monitoring of the noghol landslide however the determination of vertical displacement of the landslide by the asar images processing is more correct compared to results of the palsar processing due to the descending orbital motion of asar the asar images also overwhelm palsar images for determination of the landslide extent because of detection of more persistent scatterer points the landslide displacement and aspect obtained by the global navigation satellite system gnss and psinsar techniques are in agreement about 1 2 1 5 m westward in the period of 2003 2010 particularly processing results of the asar images are more similar to the gnss measurements furthermore assessment of the landslide type mechanism and its displacement direction were possible by integration of the palsar and asar radar images with ascending and descending orbital motions respectively

a small baseline approach for investigating deformations on full resolution differential sar interferograms this paper presents a differential synthetic aperture radar sar interferometry difsar approach for investigating deformation phenomena on full resolution difsar interferograms in particular our algorithm extends the capability of the small baseline subset sbas technique that relies on small baseline difsar interferograms only and is mainly focused on investigating large scale deformations with spatial resolutions of about 100 spl times 100 m the proposed technique is implemented by using two different sets of data generated at low multilook data and full single look data spatial resolution respectively the former is used to identify and estimate via the conventional sbas technique large spatial scale deformation patterns topographic errors in the available digital elevation model and possible atmospheric phase artifacts the latter allows us to detect on the full resolution residual phase components structures highly coherent over time buildings rocks lava structures etc as well as their height and displacements in particular the estimation of the temporal evolution of these local deformations is easily implemented by applying the singular value decomposition technique the proposed algorithm has been tested with data acquired by the european remote sensing satellites relative to the campania area italy and validated by using geodetic measurements

post caldera activity in the alban hills volcanic district italy 40ar 39ar geochronology and insights into magma evolution we present 24 40ar 39ar ages for the youngest volcanic products from the alban hills volcanic district rome combined with petrological data on these products we have attempted to define the chronology of the most recent phase of activity and to investigate the magma evolution of this volcanic district the early mainly explosive activity of the alban hills spanned the interval from 561 1 to 351 3 ka after approximately 50 kyr of dormancy a mainly effusive phase of activity took place accompanied by the strombolian activity of a small central edifice monte delle faete this second phase of activity spanned the interval 308 2 to 250 1 ka after another dormancy period of approximately 50 kyr a new hydromagmatic phase of activity started at 200 ka at several centers located to the southwest of the monte delle faete edifice after an initial recurrence period of approximately 50 kyr which also characterized this new phase of activity the longest dormancy period approximately 80 kyr in the history of the volcanic district preceded the start of the activity of the albano and giuturna centers at 70 1 ka results of our study suggest a quasi continuous magmatic activity feeding hydromagmatic centers with a new acme of volcanism since around 70 ka based on data presented in this paper we argue that the alban hills should not be considered an extinct volcanic district and a detailed re assessment of the volcanic hazard for the area of rome is in order

geomorphological significance of lichen colonization in a present snow hollow hoya del cuchillar de las navajas sierra de gredos spain abstract this paper discusses the results of a lichenometrical and geomorphological study of one of the few remaining active snow hollows in the central region of the iberian peninsula the study area located on a glacial shoulder is called hoya del cuchillar de las navajas a protalus rampart occurs at the base of the hollow our studies conducted between 1992 and 1998 were designed to determine the geomorphological characteristics of hoya the mobility of the deposits and the characteristics of the snow cover these data formed the basis for a study of the lichen colonization on the blocks and on the wall surrounding the snow hollow all of the lichen species found were analyzed according to their abundance distribution and the extent of their surface cover measurements of the diameter of the thalli of the species rhizocarpon geographicum were also obtained thalli of this species were found to require a mean snow free growing season of at least 95 days 13 5 weeks per year maximum mean thallus diameters indicate that the protalus rampart was formed during the little ice age and became inactive 130 years ago

tectonics sea level changes and palaeoenvironments in the early pleistocene of rome italy abstract the historical site of the monte mario lower pleistocene succession rome italy is an important marker of the pliocene pleistocene boundary recently the monte mario site was excavated and restudied a spectacular angular unconformity characterizes the contact between the monte vaticano and the monte mario formations which marks the pliocene pleistocene boundary biostratigraphical analyses carried out on ostracod foraminifer and calcareous nannofossil assemblages indicate an early pliocene age topmost zanclean 3 81 3 70 ma for the underlying monte vaticano formation whereas the monte mario formation has been dated as early pleistocene santernian 1 66 1 59 ma palaeomagnetic analyses point to c2ar and c1r2r polarity chrons for the monte vaticano and the monte mario formations respectively the monte mario formation consists of two obliquity forced depositional sequences mm1 and mm2 characterized by transgressive systems tracts of littoral marine environments at depths respectively of 40 80 m and 15 20 m the data obtained from foraminifer and ostracod assemblages allow us to reconstruct early pleistocene relative sea level changes near rome at the plio pleistocene transition a relative sea level drop of at least 260 m occurred as a result of both tectonic uplift of the central tyrrhenian margin and glacio eustatic changes linked to early pleistocene glaciation marine isotope stage 58

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

inflation rate of the colli albani volcanic complex retrieved by the permanent scatterers sar interferometry technique 1 we analyzed 99 ers sar images of the colli albani volcano using the permanent scatterers technique we retrieved the average surface displacement velocities for over 100 000 scatterers for the period 1993 2000 showing that present deformation is concentrated in the area of most recent volcanic activity with rates up to 2 6 mm yr in the satellite line of sight we inverted the observed deformation using several analytical solutions for volcanic sources in an elastic half space the best fit is obtained with two mogi sources aligned in a n s direction at 5 and 7 km depth beneath the western flank of the volcano

sea stack formation and the role of abrasion on beach mantled headlands sea stacks are common and striking coastal landforms but few details are known about how how quickly and under what conditions they form we present numerical and analytical models of sea stack formation due to preferential erosion along a pre existing headland to address these basic questions on sediment rich rocky coasts as sea cliffs erode and retreat they produce beach sediment that is distributed by alongshore sediment transport and controls future sea cliff retreat rates depending on their width beaches can encourage or discourage sea cliff erosion by acting either as an abrasive tool or a protective cover that dissipates wave energy seaward of the cliff along the flanks of rocky headlands where pocket beaches are often curved and narrow due to wave field variability abrasion can accelerate alongshore directed sea cliff erosion eventually abrasion induced preferential erosion can cut a channel through a headland separating it from the mainland to become a sea stack under a symmetrical wave climate i e equal influence of waves approaching the coastline from the right and from the left numerical and analytical model results suggest that sea stack formation time and plan view size are proportional to preferential erosion intensity caused by for example abrasion and or local rock weakness from joints faults or fractures and initial headland aspect ratio and that sea stack formation is discouraged when the sediment input from sea cliff retreat is too high i e sea cliffs retreat quickly or are sand rich when initial headland aspect ratio is too small and the headland is rounded much wider in the alongshore direction at its base than at its seaward apex the headland is less conducive to sea stack formation on top of these geomorphic and morphologic controls a highly asymmetrical wave climate decreases sea stack size and discourages stack formation through rock sediment interactions copyright 2014 john wiley sons ltd

changes to monterey bay beaches from the end of the 1982 83 el nino through the 1997 98 el nino abstract the shoreline of monterey bay ca usa demarcates the landward extent of the monterey bay national marine sanctuary along the length of that shoreline nine beaches were profiled 34 times between 1983 and 1998 the resulting data set provides an understanding of processes that affect beach volume width and shape monterey bay which is open to high energy waves generated in the pacific ocean comprises a range of beach environments that respond in a dramatic way to major storms such as the anomalously large el ninos in 1982 83 and 1997 98 this study relates the profile characteristics of the beaches to storminess shoreline location and geomorphic setting because the large el ninos occurred at the start and end of the study the surveys cover both periods of nearly constant beach size and periods of extreme erosion and the data show both the extent of erosion and accretion and the nature of the transition between the two periods

the influence of competition between lichen colonization and erosion on the evolution of soil surfaces in the tabernas badlands se spain and its landscape effects article i nfo badlands often contain a mosaic of soil surface types with contrasting hydrological behaviour which drives their short term geomorphic evolution the tabernas badlands in semiarid se spain show a complex mosaic of bare ground biological soil crusts and plant covered patches and high variability of covers and morphologies previous work has identified the surfaces that act as sources of runoff and sediments and those that act as sinks the pathways of runoff between surfaces and the runoff and erosion at catchment scale however surfaces without vascular plants can be quite dynamic with important effects on geomorphic processes this work aims to generate hypotheses about the dynamics of both bare soil 34 of the area and biological soil crusts 33 and to provide a first estimation of the growth rate of terricolous lichens as increase of coverage and their geomorphological implications the dynamics of ten representative soil surfaces were photographically monitored over 13 years recording the cover and pattern of bare soil and of the two main kinds of biological soil crust brown crust and white crust erosion deposition were measured by erosion pins in unbounded plots and the hydrological and erosional behaviour monitored in bounded plots under natural and simulated rainfall biological colonization and crust growth were studied from 2004 within cleared plots in four crust communities microclimate was continuously monitored in each community after 13 years net erosion was recorded only in previously eroded slopes and divides vegetated sites and those covered by biological soil crust remained more or less invariant or recorded sedimentation in all white crust surfaces whole crust cover increased by 3 on average while macrolichen cover increased by nearly 30 within the driest brown crust macrolichen cover increased by 7 while the whole crust decreased by 3 according to previous work lichen cover particularly of white crust is often greater in north to east facing orientations because of the higher slope stability and the longer duration of moisture however the increase of the whole biological soil crust can depend more on species composition and previous cover and less or not at all on the aspect although certain species do grow faster in particular orientations within the plots cleared in 2004 the greatest increase occurred in the pioneering brown crust which reached an average of 26 cover after one year in spite of it receiving the most insolation significant microclimatic differences exist among the communities mainly in radiation soil moisture and thallus surface temperature terricolous lichen crusts primary colonizers of bare sufficiently stable areas can grow quickly and by increasing soil stability and development and modifying surface hydrology they can influence surface dynamics and ultimately landform dynamics crust growth rate probably decreases as its cover increases and it probably also oscillates with microclimatic oscillations however the high potential growth rate recorded allows detection not only of climatic changes but also short term possibly seasonal periods of stability extensive lichen crusts indicate low erosion rates and particular climatic conditions variations of crust cover could indicate climatic or land use variations

the sediments of the stagno di maccarese marsh tiber river delta central italy a late holocene record of natural and human induced environmental changes the environmental evolution inferred from the sedimentary sequence that has occurred during the last three millennia in a drained coastal marsh in the tiber delta is presented the stratigraphy o

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

the albano maar lake colli albani volcano italy recent volcanic activity and evidence of pre roman age catastrophic lahar events abstract the evaluation of volcanic hazard in the roman hinterland related to the quiescent colli albani volcano has recently been the subject of renewed attention and several interpretations by many authors however very little was known of the recent history of the volcano making such interpretations rather speculative the most recent activity of colli albani volcano originated from the albano polygenetic maar lake which erupted several phreatomagmatic units the most recent of which the peperino albano ignimbrite has been dated at around 25 ka an area of several square kilometers centered around albano lake is presently the site of shallow and frequent seismic activity and gaseous emission as well as hydrothermal activity and is therefore considered the most prone to geologic hazards this paper presents new stratigraphic and geomorphologic data as well as age determinations that allow rejuvenation of the most recent activity of the colli albani volcano and particularly the albano maar lake to the holocene this study allows for the first time to identify a potential hazard related to the albano maar lake withdrawal interpreted to be related to endogenous causes namely co 2 emission the main results of the study are 1 the peperino albano is not as is generally believed the last phreatomagmatic eruption from the colli albani volcano a previously unrecognized phreatomagmatic surge deposit has been identified overlying the paleosol at the top of the peperino albano and related lahar deposits 2 two lahar deposits separated by paleosols top the stratigraphic succession and are dispersed only to the nw corresponding to the lowest point of the maar rim indicating that catastrophic hydrologic events occurred at the albano lake in recent times rapid and substantial lake level variations and lake withdrawal are reported by roman historians and recorded by the stratigraphy of the albano lake lacustrine sediments 3 microfracturing related to seismic energy release is linked to sudden variation of co 2 flow and upwelling of hydrothermal fluids these occurrences across the lake are the likely causes that triggered during holocene several episodes of lake withdrawal rising the water table and probably triggering convective rollover of the lake water

late quaternary environmental evolution of the como urban area northern italy a multidisciplinary tool for risk management and urban planning abstract the historical center of como northern italy is prone to lake flooding and subsidence due to the presence of unconsolidated silty sediments with poor mechanical properties the sedimentary basin beneath the town contains over 180 m thickness of late quaternary lacustrine palustrine and alluvial deposits the landscape evolution and the present day environmental setting of the como area have been reconstructed based on i more than 250 core logs and related geotechnical tests ii detailed stratigraphic sedimentological paleobotanical and geotechnical analysis of several key boreholes iii multi year hydrogeological monitoring iv estimation of subsidence rates and v integration of geomorphology archeological findings and historical documents based on our environmental analysis we derived an integrated geological and geomorphological model of the latest pleistocene to holocene local landscape evolution this model was used to help design an engineering facility to mitigate flood hazards in the como urban area in 2012 we carried out investigations during a re evaluation of the design parameters for the flood mitigation project at the como lake shore the new campaign included seven boreholes many in situ and laboratory tests and four 14c dates we found an organic silty unit historical in age with bad mechanical properties that was critical in the design of the flood mitigation project we also obtained index properties for static and dynamic conditions necessary for robust engineering planning the results were used to update the project and better define future executive phases although the importance of acquiring independent experimental data is often overlooked they can significantly improve the reliability of engineered systems as demonstrated by the como town case history

the holocene record of environmental changes in the stagno di maccarese marsh tiber river delta central italy the stratigraphic study of the stagno di maccarese carried out on the sediments exposed in about 7 km of trenches excavated in an area of approximately 1 5 km2 has shown that in the course of the holocene many environmental variations have taken place the complex evolution of the marsh is demonstrated by the variations in water salinity and the presence of erosion surfaces and soils between the sediments in the early holocene the area studied was an isolated marsh with water having variable salinity and it was only about 6000 cal yr bp that it was encompassed in the system of inner delta marshes in the delta environment the water of the marsh was oligohaline until about 9th 8th centuries bc brackish from 9th 8th centuries bc to about 600 yr bp and later oligohaline until the 19th century drainage a number of environmental variations are connected with local phenomena such as erosion of the beach ridges and tiber floods but the others can be correlated chronologically with climatic events rec

coastal monitoring solutions of the geomorphological response of beach dune systems using multi temporal lidar datasets vendee coast france abstract three beach and dune systems located in the northeastern part of the bay of biscay in france were monitored over 5 years with a time series of three airborne lidar datasets the three study sites illustrate a variety of morphological beach types found in this region reproducible monitoring solutions adapted to basic and complex beach and dune morphologies using lidar time series were investigated over two periods bounded by the three surveys the first period between may 2008 and august 2010 is characterized by a higher prevalence of storm events and thus has a greater potential for eroding the coast than the second period between august 2010 and september 2013 during the first period the central and northeastern part of the bay of biscay was notably impacted by storm xynthia with water levels and wave heights exceeding the 10 year return period and 1 year return period respectively despite differences in dune morphology between the sites the dune crest dhigh and the dune base dlow are efficiently extracted from each dem based on the extracted dune base an original shoreline mobility indicator is built displaying a combination of the horizontal and vertical migrations of this geomorphic indicator between two lidar datasets a geomorphic change detection is also completed by computing dems of difference dod resulting in segregated maps of erosion and deposition and sediment budgets accounting for the accuracy of lidar datasets a probabilistic approach at a 95 confidence interval is used as a threshold for the geomorphic change detection showing more reliable results however caution should be taken when interpreting thresholded maps of changes and sediment budgets because some beach processes may be masked especially on wide tidal beaches by only keeping the most significant changes the results of the shoreline mobility and geomorphic change detection show a high variability in the beach responses between and within the three study sites explained mainly by beach orientation and local factors despite variable site specific mechanisms the recovery processes redistribute the available sand more on the upper parts of the beach producing significant deposition generally in the form of embryo dunes the monitoring of the beach and dune systems with airborne lidar datasets reveals that the three study sites show diverse behaviours during the first period likely associated with storms while the analysis show more homogenous beach responses during the second period likely associated with a recovery phase

coastal erosion and recovery from a cascadia subduction zone earthquake and tsunami abstract tsunamis generated by great earthquakes threaten coastal infrastructure development and human life earlier work has documented the inland extent and frequency of past tsunamis but little is known about the magnitude of material eroded during prehistoric tsunamis and how erosion and coastal recovery are recorded in coastal stratigraphy in this study we use high resolution ground penetrating radar gpr to image and quantify coastal erosion experienced during a late holocene 900 cal bp cascadia subduction zone earthquake and tsunami along the northern california coast the gpr profiles illustrate three stratigraphic signatures created during co seismic subsidence and tsunami erosion and coastal recovery the first is erosional truncation of the underlying seaward dipping reflections created by pre tsunami normal beach progradation the second is a series of landward dipping flat lying and channelized reflections marking the filling of erosional topography and coastal reworking of the irregular shoreline following inundation and erosion the third is an abrupt landward termination of the stratigraphic unit marking coastal straightening and post tsunami rejuvenation of normal coastal progradation erosion from the 900 cal bp earthquake and tsunami extended 110 m inland of the contemporary shoreline and removed reworked 225 000 28 000 m3 of sand from a 1 7 km stretch of the coast far exceeding anything experienced during historical el ninos along the pacific coast of north america this study provides the first quantitative estimate of the amount of coastal erosion from a pre historic earthquake and tsunami and outlines a strategy for estimating erosion during similar events elsewhere

a new method for measuring deformation on volcanoes and other natural terrains using insar persistent scatterers 1 we present here a new insar persistent scatterer ps method for analyzing episodic crustal deformation in non urban environments with application to volcanic settings our method for identifying ps pixels in a series of interferograms is based primarily on phase characteristics and finds low amplitude pixels with phase stability that are not identified by the existing amplitude based algorithm our method also uses the spatial correlation of the phases rather than a well defined phase history so that we can observe temporally variable processes e g volcanic deformation the algorithm involves removing the residual topographic component of flattened interferogram phase for each ps then unwrapping the ps phases both spatially and temporally our method finds scatterers with stable phase characteristics independent of amplitudes associated with man made objects and is applicable to areas where conventional insar fails due to complete decorrelation of the majority of scatterers yet a few stable scatterers are present

mapping small elevation changes over large areas differential radar interferometry a technique that uses synthetic aperture radar sar images to measure very small 1 cm or less surface motions with good resolution 10 m over large swaths 50 km is presented along with experimental results the method could be used for accurate measurements of many geophysical phenomena including swelling and buckling in fault zones residual displacements from seismic events and prevolcanic swelling the method is based on sar interferometry where two images are made of a scene by simultaneously flying two physically separated antennas then the phases of corresponding pixels are differenced and altitude formation is deduced from some simple computation and image rectification it is also possible to use one antenna flown twice over the same scene then if the second flight exactly duplicates the track of the first an interesting possibility occurs there would be no phase changes between the images at all unless there was a physical change in the scene such as ground swelling that would alter the distance from some resolution element to the antenna since the phase changes all occur at the short carrier wavelength the basic limitation on sensitivity is only the phase noise in the system when the two imaging passes are made from flight tracks that are separated which is the case with the seasat images used here it is no longer possible to distinguish surface changes from the parallax caused by topography however with some additional computation a third image made at some other baseline may be used to remove the topography and leave only the surface changes this method was applied using seasat data to an imaging site in imperial valley california where motion effects were observed that were ascribed to the expansion of water absorbing clays phase change images of this area are shown along with associated ground truth about the presence of water problems with the technique are explored along with a discussion of future experimental possibilities on upcoming sar missions like earth observing system eos earth resources satellite ers 1 sir c and the venus imaging radar magellan

the lowest place on earth is subsiding an insar interferometric synthetic aperture radar perspective since the early 1990s sinkholes and wide shallow subsidence features wssfs have become major problems along the dead sea shores in israel and jordan sinkholes are readily observed in the field but their locations and timing are unpredictable wssfs are often difficult to observe in the field however once identified they delineate zones of instability and increasing hazard in this study we identify characterize and measure rates of subsidence along the dead sea shores by the interferometric synthetic aperture radar insar technique we analyze 16 sar scenes acquired during the years 1992 to 1999 by the european remote sensing ers 1 and ers 2 satellites the interferograms span periods of between 2 and 71 months wssfs are observed in the lisan peninsula and along the dead sea shores in a variety of appearances including circular and elongate coastal depressions a few hundred meters to a few kilometers in length depressions in ancient alluvial fans and depressions along salt diapir margins phase differences measured in our interferograms correspond to subsidence rates generally in the range of 0 20 mm yr within the studied period with exceptional high rates that exceed 60 mm yr in two specific regions during the study period the level of the dead sea and of the associated ground water has dropped by 6 m this water level drop within an aquifer overlying fine grained marly layers would be expected to have caused aquifer system consolidation resulting in gradual subsidence comparison of our insar observations with calculations of the expected consolidation shows that in areas where marl layers are known to compose part of the upper 30 m of the profile estimated consolidation settlements are of the order of the measured subsidence our observations also show that in certain locations subsidence appears to be structurally controlled by faults seaward landslides and salt domes gradual subsidence is unlikely to be directly related to the sinkholes excluding the use of the wssfs features as predictable precursors to sinkhole formation

the history of the monti sabatini and alban hills volcanoes groundwork for assessing volcanic tectonic hazards for rome abstract the volcanic rocks of rome provide chronostratigraphic constraint that is of use to geologists archaeologists and paleontologists identifying the areal distribution of these rocks their mode of emplacement and a detailed chronology of the eruptive events also is crucial for assessing local natural hazards in a volcanic tectonic context and for recognizing whether the volcanoes may erupt again in the future we have identified and dated many of the volumetrically significant eruptive units from the monti sabatini and alban hills colli albani and propose a formalized volcanic stratigraphy for rome it is probable that seismic events triggered some eruptions as several ignimbrites from the two volcanoes have statistically indistinguishable ages following a 200 kyr period of dormancy that was coincident with a pulse of regional uplift the alban hills appears to have begun recently circa 45 ka a new eruptive cycle therefore accurate assessment of volcanic tectonic hazards and estimation of possible future volcanic activity is necessary for the safety of the five million people living near these volcanoes

long term cliff retreat and erosion hotspots along the central shores of the monterey bay national marine sanctuary abstract quantification of cliff retreat rates for the southern half of santa cruz county ca usa located within the monterey bay national marine sanctuary using the softcopy geographic information system gis methodology results in average cliff retreat rates of 7 15 cm yr between 1953 and 1994 the coastal dunes at the southern end of santa cruz county migrate seaward and landward through time and display net accretion between 1953 and 1994 which is partially due to development in addition three critically eroding segments of coastline with high average erosion rates ranging from 20 to 63 cm yr are identified as erosion hotspots these locations include opal cliffs depot hill and manresa although cliff retreat is episodic spatially variable at the scale of meters and the factors affecting cliff retreat vary along the santa cruz county coastline there is a compensation between factors affecting retreat such that over the long term the coastline maintains a relatively smooth configuration the softcopy gis methodology significantly reduces errors inherent in the calculation of retreat rates in high relief areas e g erosion rates generated in this study are generally correct to within 10 cm by removing errors due to relief displacement although the resulting root mean squared error for erosion rates is relatively small simple projections of past erosion rates are inadequate to provide predictions of future cliff position improved predictions can be made for individual coastal segments by using a mean erosion rate and the standard deviation as guides to future cliff behavior in combination with an understanding of processes acting along the coastal segments in question this methodology can be applied on any high relief coast where retreat rates can be measured

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

analysis of subsidence using terrasar x data murcia case study this study was partially funded by the spanish ministry of science and technology and eu feder projects tec 2008 06764 and cgl 2009 08457 and by the generalitat valenciana project acomp 2010 082 as well as by the spanish geological and mining institute igme with the collaboration of the regional government of murcia the terrasar x images were provided by dlr in the framework of the scientific project geo0389 ers and envisat data were provided by esa in the framework of the cat1 project 2494

sequence stratigraphy and depositional setting of the tiber delta integration of high resolution seismics well logs and archeological data abstract using archeological evidence radiocarbon data well logs and high resolution seismic profiles we applied sequence stratigraphic analysis to sediments deposited during the last glacio eustatic cycle on the tyrrhenian continental margin embracing the tiber river months these sediments form a high frequency sequence of fifth order that has developed over the last 20 000 yr since the last lowstand hereafter referred to as the tiber depositional sequence tds the tds is still evolving and lies on a type 1 sequence boundary that has been identified both on the shelf and below the present delta plain this sequence consists of lowstand transgressive and highstand systems tracts the lowstand deposits are not present on the shelf but are found on the continental slope where they constitute the last progradation set of the continental margin a network of gullies active when the river mouth was at the shelf break is present within the lowstand deposits the transgressive systems tract tst deposits lie directly on the basal unconformity landwards the tst is represented by a retrogradational parasequence set of fluvial coastal barrier lagoon and lagoonal delta facies seaward on the shelf these parasequences merge into a seismically transparent deposit that forms a condensed section the flooding surfaces that bound the parasequences are marked by peat layers that were dated by 14c the radiometric ages were used to draw a carve of sea level rise for the last 11 000 yr the top of the transgressive systems tract maximum flooding surface is represented by the last peat layer which was formed about 4700 5000 yr bp and buried 4 5 m below the present upper delta plain the highstand systems tract is made up of deposits of the present tiber wave dominated delta i e upper and lower delta plain delta front and prodelta slope the aligned beach ridges mark the position of the prograding coastline which for the last 2500 yr can be dated by archeological and historical data the recent very fast progradation of the tiber delta during the last 500 years is consistent with historical data on floods of the city of rome and the suspended load of the tiber river

a quasi elastic aquifer deformational behavior madrid aquifer case study summary the purpose of this paper is to analyze the quasi elastic deformational behavior that has been induced by groundwater withdrawal of the tertiary detrital aquifer of madrid spain the spatial and temporal evolution of ground surface displacement was estimated by processing two datasets of radar satellite images sar using persistent scatterer interferometry psi the first sar dataset was acquired between april 1992 and november 2000 by ers 1 and ers 2 satellites and the second one by the envisat satellite between august 2002 and september 2010 the spatial distribution of psi measurements reveals that the magnitude of the displacement increases gradually towards the center of the well field area where approximately 80 mm of maximum cumulated displacement is registered the correlation analysis made between displacement and piezometric time series provides a correlation coefficient greater than 85 for all the wells the elastic and inelastic components of measured displacements were separated observing that the elastic component is on average more than 4 times the inelastic component for the studied period moreover the hysteresis loops on the stress strain plots indicate that the response is in the elastic range these results demonstrate the quasi elastic behavior of the aquifer during the aquifer recovery phase ground surface uplift almost recovers from the subsidence experienced during the preceding extraction phase taking into account this unique aquifer system a one dimensional elastic model was calibrated in the period 1997 2000 subsequently the model was used to predict the ground surface movements during the period 1992 2010 modeled displacements were validated with psi displacement measurements exhibiting an error of 13 on average related with the inelastic component of deformation occurring as a long term trend in low permeability fine grained units this result further demonstrates the quasi elastic deformational behavior of this unique aquifer system

sand mining impacts on long term dune erosion in southern monterey bay abstract southern monterey bay was the most intensively mined shoreline with sand removed directly from the surf zone in the u s during the period from 1906 until 1990 when the mines were closed following hypotheses that the mining caused coastal erosion it is estimated that the yearly averaged amount of mined sand between 1940 and 1984 was 128 000 m 3 yr which is approximately 50 of the yearly average dune volume loss during this period to assess the impact of sand mining erosion rates along an 18 km range of shoreline during the times of intensive sand mining 1940 1990 are compared with the rates after sand mining ceased 1990 2004 most of the shoreline is composed of unconsolidated sand with extensive sand dunes rising up to a height of 46 m vulnerable to the erosive forces of storm waves erosion is defined here as a recession of the top edge of the dune recession was determined using stereo photogrammetry and lidar and gps surveys long term erosion rates vary from about 0 5 m yr at monterey to 1 5 m yr in the middle of the range and then decrease northward erosion events are episodic and occur when storm waves and high tides coincide allowing swash to undercut the dune and resulting in permanent recession erosion appears to be correlated with the occurrence of el ninos the calculated volume loss of the dune in southern monterey bay during the 1997 98 el nino winter was 1 820 000 m 3 which is almost seven times the historical annual mean dune erosion of 270 000 m 3 yr the alongshore variation in recession rates appears to be a function of the alongshore gradient in mean wave energy and depletions by sand mining after cessation of sand mining in 1990 the erosion rates decreased at locations in the southern end of the bay but have not significantly changed at other locations

late quaternary glacial phases in the iberian peninsula abstract the only glaciers existing today in the iberian peninsula are small features located in the pyrenees though their number and extension has undergone significant changes over the late quaternary the wide range of glacial landforms and deposits distributed across different iberian ranges suggests the occurrence of several past periods with larger glacial systems the objective of this research is to summarize the current knowledge on the spatial and temporal patterns of glacial activity in the iberian mountains during the late quaternary to this purpose the chronological framework was divided in six periods glaciations prior to the last glacial cycle middle pleistocene last glacial cycle late pleistocene termination 1 holocene little ice age lia and present day the data were geographically divided considering the mountain systems where glacial evidence exists pyrenees cantabrian range nw ranges central range iberian range and sierra nevada during quaternary cold stages ice accumulated in the head valleys of these mountain ranges and glaciers flowed down valleys in all cases glaciers remained confined within the mountain systems and did not reach the surrounding lowlands depending on the combination of temperatures and moisture conditions more or less ice was stored in some ranges there is evidence of middle pleistocene glaciations one potentially correlating with marine isotope stage mis 12 and another correlating with mis 6 with glaciation dated to ca 130 170 ka however most of the glacial records correspond to the last glacial cycle and subsequent termination the maximum glacial expansion of this last pleistocene glaciation stage occurred well before the global last glacial maximum lgm between 30 and 60 ka in the cantabrian mountains and pyrenees at ca 30 ka in sierra nevada and nw ranges and almost synchronously to the lgm in the central range and iberian range a massive glacial retreat occurred in all ranges at 19 20 ka but the long term deglaciation process was interrupted by cold intervals such as the oldest and younger dryas which favoured glacial expansion in the highest mountains temperature increase recorded during the holocene conditioned the melting of glaciers which only reappeared in the highest massifs during the coldest periods such as the lia however post lia warming led to glacier disappearance in the cantabrian mountains sierra nevada and most massifs of the pyrenees together with an accelerated shrinkage of the small glaciers still existing in this range at elevations near 3000 m

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

maximum glacial advance and deglaciation of the pinar valley sierra de gredos central spain and its significance in the mediterranean context abstract pinar valley is located on the north side of galana peak 40 15 21 n 5 18 00 w 2564 m a s l sierra de gredos in the center of the iberian peninsula surface exposure ages based on the in situ accumulation of 36 cl were obtained from six moraine boulders and from three bedrock outcrops to investigate the timing of both the last local glacial maximum and the deglaciation the oldest moraines which probably overrode older glacial deposits are coeval to the global last glacial maximum subsequently the pinar glacier underwent minor pulsations close to its maximum position followed by general glacier retreat after 17 16 ka small cirque glaciers probably remained during the terminal pleistocene but they had completely disappeared by 10 ka

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

recent uplift of the alban hills volcano italy evidence for magmatic inflation first order leveling surveyed in 1951 and 1994 along a line across the alban hills volcano reveals maximum vertical uplift of 30 cm average of 7 mm yr in the region of geologically recent 0 020 0 030 ma explosive activity the uplifted region corresponds to an area where seismic activity is concentrated at depths of 3 6 km uplift exceeding 10 cm is observed over a 14 km wide zone in the center of a 40 km long line with the deformation tapering to zero at both ends of the line data from a few sparse older benchmarks measured in 1891 and 1927 suggest that the deformation in the first half of this century was very small compared to the period 1951 1994 the observed uplift together with increased seismic activity suggest that recent magma injection has occurred in the upper crust beneath the alban hills volcano

last glacial maximum and deglaciation of sierra de gredos central iberian peninsula abstract the study area is located in the sierra de gredos a portion of the sistema central range of central spain specifically in the gredos gorge on the north side of pico almanzor 2596 masl where glacial forms are present down to an altitude of 1410 m 10 km from the headwall this paper presents cosmogenic 36 cl surface exposure dates of four closely spaced lateral moraine ridges within the area of maximum advance of the ancient glacier 8 km from the headwall and two glacially polished bedrock thresholds 3 and 5 km from the headwall the dates are overall coherent and indicate a maximum advance at 26 24 ka subsequently the glacier front stabilized around its maximum position for 3 ka with small scale fluctuations resulting in small closely spaced moraines ridges glacier recession began after 21 ka accelerating sharply by 16 ka the glacier had probably disappeared from the gredos gorge by 15 ka there are no traces of older or more recent moraines than those dated in this study these results are in agreement with the well known late pleistocene climatic evolution of the northern atlantic and with the glacial chronology of the alps and other mediterranean mountains however the gredos gorge has no geomorphic evidence of the younger dryas cold event probably because of the low altitude and southern character of these mountains

physical stratigraphy and sedimentology of the late pleistocene holocene tiber delta depositional sequence the tiber delta lies on the passive continental margin of central western italy the tiber delta is a late pleistocene holocene sedimentary succession and constitutes an incomplete high frequency depositional sequence 4th or 5th order which developed from the last post glacial rise in sea level to the present stillstand it is bound by a type 1 basal unconformity which cuts pleistocene deposits five depositional systems have been identified 1 coastal barrier lagoon 2 shelf transition 3 fluvial braided 4 tiber lagoonal deltas t1 t2 t3 and 5 tiber wave dominated delta the first four systems constitute the transgressive system tract tst which is characterized by a retrogradational parasequences set while the fifth system represents the highstand system tract hst characterized by only one parasequence progradational the evolution of these depositional systems has been mostly controlled by sea level rise which was not continuous but punctuated by eight minor stillstands and rapid rises this mechanism of sea level change led to the formation of parasequences that developed within the depositional systems from a palaeogeographical point of view the present tiber delta area was mainly characterized by a coastal barrier lagoon and tiber lagoonal deltas t1 t2 t3 which migrated landwards during the sea level rise throughout the time of the present stillstand the t3 lagoonal delta prograded rapidly into the lagoon reaching the coastal barrier and the lagoon was replaced first by marshes and then by the alluvial plain finally the tiber river overcame the littoral barrier supplying the coast giving rise to the present wave dominated delta

using provenance analysis in an anthropocene natural laboratory abstract globally anthropogenic perturbations to sediment dispersal systems produce detrital signals that are evident in the recent sedimentary record we review the study of anthropogenic perturbations to sediment dispersal systems from the perspective of detrital signals and discuss the use of provenance analysis in anthropocene sedimentology anthropocene provenance analysis is illustrated by a case study from the monterey bay sediment dispersal system mbds of coastal and offshore central california u s a the mbds records two phases of alterations to sediment flux an early increase in fine flux recognized in increased sedimentation rates and a later decrease in coarse flux recognized in detrital provenance signatures results from the mbds suggest that a multi methodological approaches employing provenance analysis and detailed short timescale 102 104 yr depositional chronology markers combined with the study of other anthropocene indicators like the introduction of non natural detritus are valuable tools for describing natural sedimentary processes in addition to human alterations to natural systems the recognition and description of such perturbations to sediment supply is increasingly recognized as an important variable in understanding the effects of human driven landscape alteration particularly in the face of a changing climate the broad concepts and approach outlined in this study provide tools that can extend environmental observations past the period of historical record and can be used to understand past and predict future impacts of altered sediment flux in response to drivers like climate change and sea level rise

geotechnical studies for foundation settlement in holocenic alluvial deposits in the city of rome italy abstract this study identifies units characterized by specific geomechanical behaviours within some holocene alluvial deposits in the city of rome in particular the highly compressible units which may be responsible for subsidence and settlement phenomena below urban structures have been identified investigations carried out during this study have interpreted nearly 800 stratigraphic sections and physical mechanical features of the alluvial deposits of the tiber and those of its right and left bank tributaries the analysis allowed to define for each investigated deposit a representative series subdivided into lithotechnical units when comparing the stratigraphic and geologic features among the series a remarkable difference in geomechanical behaviour in the deposits from the tiber s left and right bank tributaries and within the river s deposits themselves could be recognized a yield hazard zoning for urban structures related to recent alluvial deposits has also been defined

integrating geomorphological mapping trenching insar and gpr for the identification and characterization of sinkholes a review and application in the mantled evaporite karst of the ebro valley ne spain abstract this contribution illustrates the advantages of integrating conventional geomorphological methods with insar ground penetrating radar and trenching for sinkhole mapping and characterization in a mantled evaporite karst area where a significant proportion of the karstic depressions have been obliterated by artificial fills the main practical aim of the investigation was to elucidate whether buried sinkholes overlap the areas planned for the construction of buildings and services in order to apply a preventive planning strategy old aerial photographs and detailed topographic maps were the most useful sources of information for the identification of sinkholes and helped to obtain information on their chronology either a minimum age or bracketing dates the insar technique provided subsidence rate values ranging from 4 4 to 17 3 mm yr consistent with the spatial distribution of the mapped sinkholes this quantitative deformation data helped corroborating independently the existence of active buried sinkholes and improving the delineation of their limits the gpr profiles contributed to the precise location of sinkhole edges provided information on the geometry of buried sinkholes and deformation structures and helped to site trenches and to rule out the existence of sinkholes in particular areas the main input derived from the trenches includes 1 confirming or ruling out anomalies of the gpr profiles attributable to subsidence 2 precise location of the edge of some filled sinkholes 3 information on subsidence mechanisms recorded by various deformation structures and cumulative subsidence magnitude 4 calculating minimum long term subsidence rates using radiocarbon dates obtained from deformed sinkhole deposits 5 unequivocal evidence of active subsidence in areas assigned for the construction of buildings

volcanic unrest of the colli albani central italy detected by gps monitoring test this work has been partially supported by the dept of civil protection project dpc115 v3 colli albani

spatial and temporal variability of periglaciation of the iberian peninsula abstract active periglacial processes are currently marginal in the iberian peninsula spatially limited to the highest mountain ranges however a wide variety of periglacial deposits and landforms are distributed in low and mid altitude environments which shows evidence of past periods of enhanced periglacial activity the purpose of this paper is to summarize the present knowledge of past periglacial activity in the iberian peninsula the chronological framework takes four main stages into account the last glaciation deglaciation holocene and present day processes this study focuses on the highest massifs pyrenees cantabrian range nw ranges central range iberian range sierra nevada as well as other lower elevation environments namely the central iberian meseta during the last glaciation the periglacial belt extended to much lower altitudes than today reaching current sea level in the nw corner of the iberian peninsula a wide range of geomorphological landforms and sedimentary records is indicative of very active periglacial processes during that phase in some cases related to permafrost conditions i e block streams rock glaciers most of the inactive landforms and deposits in low and mid elevations in iberia are also related to this phase the massive deglaciation of the iberian massifs was caused by a gradual increase in temperatures the deglaciation phase was only interrupted by a short period with colder conditions the younger dryas that reactivated periglacial processes in the formerly glaciated cirques of the highest lands specifically with the widespread development of rock glaciers during the holocene periglacial processes have been only active in the highest ranges shifting in altitude according to temperature regimes and moisture conditions the little ice age saw the reactivation of periglacial activity in lower elevations than today currently periglacial processes are only active in elevations exceeding 2500 m in the southern ranges and above 2000 2200 m in the northern massifs higher in sierra nevada in the south of iberian peninsula

dinsar measurements of ground deformation by sinkholes mining subsidence and landslides ebro river spain differential interferometric synthetic aperture radar dinsar has been applied to detect and measure ground deformation in a stretch of the ebro river valley spain excavated in salt bearing evaporites the capability of the small baseline subset sbas dinsar technique to detect ground displacement is analyzed comparing the dinsar results with the available geomorphological information the deformation map derived from 27 european remote sensing ers satellite images covering more than five years provides sub centimeter displacement measurements in zones coinciding with known active sinkholes and landslides moreover the map provides the first account of mining subsidence in the area the measured deformation rates reach 1 68 cm y for the sinkholes 0 80 cm y for the landslides and 1 45 cm y for the area affected by mining subsidence the sbas dinsar technique provided deformation measurements in a small proportion 5 10 of the known active sinkholes and landslides this limitation is mainly due to the lack of coherence in agricultural areas the spatial resolution of the deformation map pixel size of 90 m and the parallelism between the ers satellite line of sight and the linear escarpment on which most of the landslides occur despite this the interferometric technique provides valuable data that complement traditional geomorphological studies including the quantification of the deformation phenomena the identification of mining subsidence otherwise only recognizable by geodetic methods and the detection of creep deformation which might correspond to premonitory indicators of catastrophic sinkholes and landslides capable of causing the loss of lives detailed dinsar studies combined with field data would be required to improve the analysis of each deformation area copyright 2009 john wiley sons ltd

seismic stratigraphy and late quaternary shelf history south central monterey bay california abstract the south central monterey bay shelf is a high energy wave dominated tectonically active coastal region on the central california continental margin a prominent feature of this shelf is a sediment lobe off the mouth of the salinas river that has surface expression high resolution seismic reflection profiles reveal that an angular unconformity quaternary underlies the entire shelf and separates undeformed strata above it from deformed strata below it the salinas river lobe is a convex bulge on the shelf covering an area of approximately 72 km 2 in water depths from 10 to 90 m it reaches a maximum thickness of 35 m about 2 5 km seaward of the river mouth and thins in all directions away from this point adjacent shelf areas are characterized by only a thin 2 to 5 m thick and uniform veneer of sediment acoustic stratigraphy of the lobe is complex and is characterized by at least three unconformity bounded depositional sequences acoustically these sequences are relatively well bedded acoustic foresets occur within the intermediate sequence and dip seaward at 0 7 to 2 0 comparison with sedimentary sequences in uplifted onshore pleistocene marine terrace deposits of the monterey bay area which were presumably formed in a similar setting under similar processes suggests that a general interpretation can be formulated for seismic stratigraphic patterns depositional sequences are interpreted to represent shallowing upwards progradational sequences of marine to nonmarine coastal deposits formed during interglacial highstands and or during early stages of falling sea level acoustic foresets within the intermediate sequence are evidence of seaward progradation acoustic unconformities that separate depositional sequences are interpreted as having formed largely by shoreface planation and may be the only record of the intervening transgressions the internal stratigraphy of the salinas river lobe thus suggests that at least several late quaternary regressions and transgressions may be recorded under the present shelf this record may represent the last major eustatic cycle of sea level an interval not observed in uplifted onshore pleistocene marine terraces

stratigraphic and tectonic features of the middle pleistocene sedimentary and volcanic deposits in the area of rome italy the analysis of a large number of stratigraphic logs from boreholes as well as an extensive field survey suggests that the middle pleistocene sedimentary deposits in the area of rome can be subdivided into two groups each one characterised by a different stratigraphy and tectonic setting a north eastern sector corresponding to the eastern urban area of rome and a south western sector corresponding to the ponte galeria area in the north eastern sector the distribution of sediments is influenced by vertical block faulting showing a predominantly north south trend superimposed on a middle pleistocene ne sw extensional tectonic domain in the south western sector we suggest that the ponte galeria formation auct can be subdivided into two depositional sequences that can be linked to isotope stages 19 and 21 in addition a sedimentary hiatus is proposed at the top of the ponte galeria sequence it corresponds to the deposition of a continental succession in the north eastern sector before the emplacement of pyroclastic deposits from the colli albani and sabatini volcanic districts the correlation between these two depositional sequences that have been identified and the oxygen isotope time scale allowed us to extend our investigation across to the urban area of rome where we have recognised six sedimentary cycles all of pleistocene age which have been tentatively related to particular isotopes stages

evidence of active crustal deformation of the colli albani volcanic area central italy by gps surveys abstract colli albani is a volcanic complex located in central italy very close to the city of rome its last eruption is dated at 0 03 0 02 ma now it displays a recurrent seismicity sporadic gas emissions from soils wells and springs and post volcanic hydrothermal circulation moreover an uplift of about 30 cm over the last 43 years was recently detected by comparing the height differences between some vertices of repeated leveling surveys thus suggesting a recent active magmatic process beneath the volcano in 1995 a first epoch gps campaign was carried out with last generation receivers the repetition campaign was performed in 1996 data coming from the two repeated surveys were carefully processed and analyzed a statistical analysis rigorously applied between the 1995 and 1996 adjusted coordinates shows significant coordinate differences some sites of the network in particular the sites of vivaro vvr cava di ciampino cva and istituto nazionale di geofisica ingr display a significant subsidence of 2 6 0 7 2 7 0 8 and 2 0 0 8 cm respectively with a confidence interval at 95 percent level this subsidence seems to be induced by a water table level lowering in vivaro while in the area where the sites of cava di ciampino and ingr are located this motion is also confirmed by historical levelling data that show a subsidence of 2 cm yr during the last 45 years and could be due to local tectonics moreover significant planimetric deformations are exhibited by the site of castel romano csr it is remarkable that the stations of cva ingr and csr are located in the area that was struck by the june 12 1995 m d 3 8 earthquake although the displacement vectors are quite small the motion of the capranica prenestina cpr station which shows an uplift of 2 7 0 7 cm must be considered separately being located outside the volcanic structure and placed over the carbonatic outcrops of the prenestini mts furthermore the accuracy obtained in height determinations does not allow us to confirm if the central part of the gps network corresponding to the area investigated by amato and chiarabba is uplifting within the analyzed time span

subsidence and sinkhole hazard assessment in the southern dead sea area jordan the dead sea area is increasingly facing serious subsidence and sinkhole hazards on march 22 2000 the dyke of a two month old major salt evaporation pond located along the shore of the lisan peninsula jordan collapsed over almost two kilometers the pond was set up over unstable new lands that have been progressively emerging during the last three decades in one hour 56 millions m 3 of brine poured out into the northern natural part of the sea here we present data suggesting that the drop of the water level in conjunction with the particular tectonic setting of this area is at least one of the factors that led to the disaster we focused our study over the northern part of the lisan peninsula and ghor al haditha which are two places undergoing the most intense deformations along the jordanian dead sea coast we used the results of a static high precision gravimetric survey to detect subsurface cavities in ghor al haditha we analyzed a interferometric digital terrain model of the recent emerged platform of the lisan peninsula and interpreted radar differential interferograms contemporary with gravity measurements for the peninsula we discuss the possibilities to detect assess and monitor areas prone to collapse on the jordanian side of the southern dead sea coast

first demonstration of airborne sar tomography using multibaseline l band data in synthetic aperture radar sar interferometry the phase differences between two different sensor positions are used to estimate the terrain topography although it is possible in this way to find a three dimensional 3d surface representation the distribution of the different scatterers in the height direction at a fixed range and azimuth position remains unknown contrary to this tomographic techniques enable a real geometric resolution capability in the height direction and introduce new possibilities for many applications and inversion problems even misinterpretations in sar images caused by layover and foreshortening effects can be solved by the tomographic processing in this paper the successful experimental realization of polarimetric airborne sar tomography is demonstrated for the first time the authors present the concept of aperture synthesis for tomographic imaging for the case of a multibaseline imaging geometry and discuss the constraints arising from the limited number of flight tracks they propose a method for reduction of the height ambiguities associated to the irregular and undersampled spatial distribution of the imaging positions finally they address the experimental requirements for polarimetric airborne sar tomography and show experimental results using a multibaseline data set acquired in l band by dlr s experimental sar e sar of a test site near oberpfaffenhofen germany