surface and subsurface data integration and geological modelling from the little ice age to the present in the ravenna coastal plain northwest adriatic sea emilia romagna italy abstract new geological analysis of the ravenna coastal plain has allowed a major update of the geological coastal model with anthropogenic overprints removed from an area heavily affected by human actions in the last four centuries a period in which the little ice age lia has had a large influence on the coastal dynamics the geological build up of the coastal plain is a natural occurrence that is important for understanding the present day coastal buildup however coastal zone anthropization has defined the actual coastal morphology canceling out most of surface expression needed to create an accurate coastal evolution model as the beach ridges morphology in the study area as the lack of surface expression due to the anthropogenic actions has changed the coastal zone under study it is not possible to only use geomorphological analysis to construct a local coastal evolution model because of this building a new model and understanding how coastal evolution would proceed without human influence would allow us to understand the interaction between natural forces and anthropogenic influence which has acted to shape the actual morphology of the study area from the lia period to the present days we therefore propose an integration of data using the following actual data from the surface such as the high resolution digital surface model dsm and the digital terrain model dtm the actual database from the emilia romagna region geological survey including the shapefile with the regional soil chart and the geological elements present in the study area knowledge from previous work carried out in the area and the subsurface data from ground penetrating radar gpr which would make the study the first to use a gpr survey of the coastal plain of the northwest adriatic in addition the work will follows a successful case study done in the southern brazilian coastal plain that integrated previous works done in the coastal plain with new methods such as gpr data acquisition the gpr data allows for corroboration of the interpretation of the coastal model constructed using the surface data finally the surface geological model proposed in this work may aid by providing the following i a new means for local coastal geology research ii a methodology to apply to other barrier lagoon systems around the world in order to update our knowledge about these systems and iii powerful information to support coastal managers and decision makers in constructing a long term master plan for effective integrated coastal zone management

topographic expressions of mantle dynamics in the mediterranean abstract the surface of the earth is the ever changing expression of the dynamic processes occurring at depth and at or above its surface however our ability to read landscapes in terms of their underlying tectonic or climatic forcing remains rudimentary during the last decade particular attention has been drawn to the deep dynamic contributions to topography related to the stresses that are produced at the base of the lithosphere by mantle convection and their relevance compared to the iso static component of topography here we use examples from the mediterranean and estimate residual and dynamic topography we then compare those with surface uplift from geology for specific regions to disentangle the dynamic from the static components considering the different topographic signatures of tectonic processes e g actual residual and dynamic topography as well as uplift rates jointly provides a powerful way to distinguish between the contributions of mantle crustal and surface processes such an approach might bring us closer to reading topographic expressions in terms of their geological cause

impact of halite dissolution subsidence on quaternary fluvial terrace development case study of the huerva river ebro basin ne spain abstract this paper analyses the control of evaporite dissolution subsidence on the evolution of the lower 30 km long reach of the huerva river up to its confluence with the ebro river in the study area the huerva river flows across different interfingered lithofacies of the subhorizontally lying ebro basin fill 1 shales and sandstones upstream of cadrete 2 evaporites dominated by gypsum between cadrete and cuarte 3 gypsum with glauberite and halite units in the subsurface downstream of cuarte the halite shows a marked downvalley increase in thickness twelve terrace levels and seven pediment levels correlative to some of the terraces have been mapped in the studied area upstream of cadrete the terrace deposits with a relatively constant thickness less than 4 m and overlying unsoluble bedrock remain undeformed between cadrete and cuarte the deposits of some terraces show local thickening 60 m thick terrace alluvium that fills a 5 km long trough generated by synsedimentary subsidence phenomena caused primarily by the interstratal dissolution of halite the older terraces t1 to t4 show slight thickening 18 m and locally truncate paleocollapse structures ascribed to the interstratal karstification of halite beds the intermediate terraces t5 to t7 correspond to degradation surfaces that grade downstream of cuarte into aggradation flights underlain by the abruptly thickened deposits that fill this 5 km long dissolution trough subsidence migrated episodically downstream during the generation of these terraces and the subsidence aggradation rate was probably large enough to induce a base level drop and knickpoint migration upstream generating strath terraces with convergent longitudinal profiles the sedimentological changes that show the thickened terrace deposits in the subsidence area high proportion of overbank fines 60 including palustrine facies gravel channels with lower width depth ratio multiple fining upward cycles decrease in the calibre of the channel gravels indicate a change in the channel pattern from braided to meandering due to the lowering of the valley slope in the reach affected by subsidence some of the anomalous features of the lower terraces t8 to t12 attributable to dissolution subsidence include 1 steepening of the t8 terrace profile 2 change of the t10 terrace from degradational to aggradational downstream cuarte and 3 thickening recorded beneath the t11 terrace surface

separating natural and anthropogenic vertical movements in fast subsiding areas the po plain n italy case the geological and the anthropogenic components of vertical movement act on different time scales millions to thousands years and hundreds to tens of years respectively this peculiarity has been used in order to separate the factors controlling sea level changes in the po plain area the component due to long term geological processes is calculated from stratigraphic data commercial wells and seismic lines adding to this long term component the contribution of pleistocene deglaciation obtained from analytical models an estimate of the total natural component of vertical velocities is obtained the validity of these values is confirmed by comparison with velocities obtained from archaeological data and detailed palynological and paleontological analyses the anthropogenic components can be inferred by comparison between the total natural vertical velocities we calculate and vertical velocities obtained from other data sets two applications are proposed using tide gauge records and geodetic data respectively

wavelet analysis of remote sensing and discharge data for understanding vertical ground movements in sandy and clayey terrains of the po delta area northern italy abstract subsidence phenomena change the proneness of urban and coastal areas to huge flooding particularly in river delta regions many natural and or anthropic processes can induce vertical ground movements identifying the causes of the observed phenomena is a useful even if not easy task for flood forecasting in order to improve the knowledge of natural versus anthropic contributions to vertical ground movements in the present work data analysis techniques polynomial regression analysis frequency analysis and cross wavelet and wavelet coherence analysis are used to analyze both the long and short time scale dependencies between continuous global positioning system cgps and variations of meteorological hydrogeological and hydrological data collected in the po river delta area northern italy from january 2009 to december 2015 the main findings are as follows i occurrence of positive correlations and periodic oscillations of about 2 3 years for all the analyzed meteorological hydrogeological and hydrological records ii a general decrease of the ground level with a faster soil lowering in clayey terrain with respect to sandy terrain and iii negative correlations between cgps and po river discharge records at the intra annual scale 2 6 months which are attributed to an isostatic rebound induced by the change of the river discharge due to precipitation changes over northern italy

coastline regression of the romagna region italy due to natural and anthropogenic land subsidence and sea level rise the romagna coastal area in the northern adriatic sea has experienced in recent times continuous changes because of its precarious environment and low ground elevation above mean sea level msl major processes that may influence the stability of the coast profile include land subsidence of both natural and anthropogenic origin and the msl rise caused by global climate change according to the most accredited modeling predictions msl is expected to rise by almost 0 5 m over the next century because of the greenhouse effect natural land subsidence is the result of deep downward tectonic movement and consolidation of geologically recent deposits it may be estimated in the range of 2 2 5 mm yr in the ravenna area and twice as much in the po river delta anthropogenic land subsidence is primarily related to groundwater pumping from the upper fresh water aquifer system and gas production from plio pleistocene reservoirs geodetic surveys from 1953 to 1990 provide documentary evidence of cumulative land settlement exceeding 0 8 m and 1 2 m at marina di ravenna and cesenatico respectively in this study we estimate both natural and anthropogenic land subsidence for the years 2015 2050 and 2100 with the aid of ad hoc finite element simulation models the use of these predictions together with the expected msl rise shows that many present lowlands may be permanently submerged at the end of the next century the extent of the flooded area of the romagna coastal region can be as much as 690 and 910 km2 using optimistic and pessimistic land subsidence scenarios respectively a local detailed analysis indicates that the areas around the cities of ravenna and cesenatico may be seriously affected by sea water ingression while the city of rimini is well protected because of its relatively high elevation above msl

gps based monitoring of land subsidence in the po plain northern italy abstract we use regional and local networks of continuously operating gps stations cgps distributed in the northern central part of the italian peninsula to investigate the subsidence phenomenon of the po plain sedimentary basin and vertical movements of the surrounding areas the observations of 146 scientific and commercial stations are analyzed and compared adopting analytical techniques widely used to study gps coordinate time series the use of simple antenna supports in commercial installations instead of a more rigorous geodetic monument does not seem to induce significant differences in the noise characteristics and in the amplitudes of annual and semi annual periodic signals the vertical velocity field deduced from 129 sites with observation time spans greater than one year located in the central northern italian peninsula indicates the presence of two mainly subsidence areas the po plain and the arno plain while the sites located in the alps and apennine domains show relatively low uplift the areas of the po plain monitored by gps seem to indicate that the subsidence rate is constant or in some cases decreasing with respect to the values obtained from the last measurements performed up to 2006 by means of both sar and levelling techniques only the central part of the eastern po plain close to the apennine border modena city area is characterized by a peak in subsidence consisting in a velocity of about 15 mm yr

compaction induced stress variations with depth in an active anticline northern apennines italy 1 it is shown that the stress field can vary with depth even within a homogeneous tectonic setting as documented for the active mirandola fault related fold along the buried front of the northern apennines analyses of borehole breakouts and other well data integrated with seismological information and field evidence show that extension perpendicular to the fold axis above approximately 1200 m changes to a strike slip stress field and finally to compression near the main detachment at depth similar along depth strain variations recognized in non active anticlines are usually explained by invoking tangential longitudinal strain folding i e stretching above and shortening below a neutral surface or gravitational instabilities however in this study we propose that differential compaction may play a significant and generally overlooked role with the aid of numerical modeling it is shown that where fold limbs are onlapped by highly compactable deposits as in the mirandola area differential compaction induces stretching at shallow 1 2 km depths the amount of stretching is a function of the shape of the fold and of the thickness of the syn tectonic sediments we conclude that in the mirandola case study the stress variations observed with depth are the result of a combination of a regional compression at depth and local tension driven by differential compaction of growth strata on the limbs of the anticline with respect to its crest

reconstruction of sediment supply from mass accumulation rates in the northern adriatic basin italy over the past 19 000 years reconstruction of sediment supply is hampered by the incompleteness of the stratigraphic record this problem may be partly circumvented by studying mass accumulation rates in closed systems i e basins in which no sediment has bypassed the site of deposition over the time interval of interest we present time averaged basin wide mass accumulation rates and their associated uncertainties from a well documented closed basin the northern adriatic basin italy spanning the time interval from 19 ka b p to the present the sediment masses of five basin wide lithosomes and their associated uncertainties are derived by means of stochastic simulation using highresolution seismic data porosity profiles and radiocarbon datings this study demonstrates that inferring rates of sediment supply from conformity bounded stratigraphic units is feasible as indicated by the excellent agreement of our results of mass accumulation over the past 400 years with two independently derived estimates formation of the stratigraphic record is not an instantaneous process by comparing spatial patterns of mass accumulation rates on three different timescales decadal centennial and millennial we demonstrate a low preservation potential of sediments presently accumulating near the coast and a continuous cross shore and alongshore sediment transport regime the change from transient to persistent accumulation patterns in the highstand systems tract of the northern adriatic basin occurs at the centennial to millennial timescale intrabasinal erosion and recycling of sediments obscure the relation between rates of sediment supply and net basin wide mass accumulation which limits the amount of information that can be extracted from the stratigraphic record hence a mismatch between rates of sediment supply and accumulation rates is expected for unconformity bounded sequence stratigraphic units given the uncertainties associated with our estimates we are unable to reject the hypothesis that net basin wide mass accumulation rates have been constant over the time interval of 19 000 years at a 10 significance level

apennines subduction related subsidence of venice italy 1 the foreland regional monocline related to the northern apennines subduction can be followed from the po basin to the friuli region italy at least 240 km north eastward in seismic reflection profiles of the po basin and of the northern adriatic sea the dip of the regional monocline gradually decreases from about 22 to close to 0 pleistocene sediments onlap and pinchout to the northeast venice is located on a segment of the active monocline dipping about 1 8 to the southwest in sediments around the venice area the 1 43 ma limit is in the 960 1500 m depth range indicating a long term subsidence rate of about 0 7 1 0 mm yr therefore a significant part of the natural component of the town subsidence is related to the north eastward retreat of the adriatic subduction the subduction related downflexure affects the whole of the po plain basin and part of the southern alps where it opposes to the general uplift related to orogenesis

occurrence and development of folding related to normal faulting within a mechanically heterogeneous sedimentary sequence a case study from inner moray firth uk folds associated with normal faults are potential hydrocarbon traps and may impact the connectivity of faulted reservoirs well calibrated seismic reflection data that image a normal fault system from the inner moray firth basin offshore scotland show that folding was preferentially localized within the mechanically incompetent lower middle jurassic pre rift interval comprising interbedded shales and sandstones and within upper jurassic syn rift shales upward propagation of fault tips was initially inhibited by these weak lithologies generating fault propagation folds with amplitudes of c 50 m folds were also generated or amplified by translation of the hanging wall over curved convex upward fault planes these fault bends resulted from vertical fault segmentation and linkage within mechanically incompetent layers the relative contributions of fault propagation and fault bend folding to the final fold amplitude may vary significantly along the strike of a single fault array in areas where opposite dipping conjugate normal faults intersect the displacement maxima are skewed upwards towards the base of the syn rift sequence i e the free surface at the time of fault initiation and significant fault propagation folding did not occur these observations can be explained by high compressive stresses generated in the vicinity of conjugate fault intersections which result in asymmetric displacement distributions skewed towards the upper tip with high throw gradients enhancing upward fault propagation our observations suggest that mechanical interaction between faults in addition to mechanical stratigraphy is a key influence on the occurrence of normal fault related folding and controls kinematic parameters such as fault propagation slip ratios and displacement rates

recent and active tectonics of the external zone of the northern apennines italy we present a comprehensive study of the recent and active tectonics of the external part of the northern apennines italy by using morphotectonic geological structural and stratigraphic analysis compared with the current seismicity of the region this analysis suggests that the external part of the northern apennines is characterised by presence of three major systems of quaternary compressive structures corresponding to 1 the apenninic watershed 2 the apennines po plain margin pede apenninic thrust front and 3 the emilia ferrara and adriatic fold systems buried below the po plain geological data and interpreted seismic sections indicate a roughly n s quaternary deformation direction with rates 2 5 mm year the shortening decreased since the pliocene when our data indicate compression in a nnw sse direction and rates up to 7 mm year the trend and kinematics of the structures affecting the apennines po plain margin and the po plain subsoil fit well the pattern of the current seismicity of the area as well as recent gps and geodetic levelling data pointing to a current activity of these thrust systems controlled by an overall compressive stress field close to the apenninic watershed earthquake focal mechanisms indicate that shallow extension is associated to deep compression the extensional events may be related to a secondary extensional stress field developing on the hangingwall of the thrust system affecting the apenninic watershed alternatively this thrust system may have been recently deactivated and overprinted by active normal faulting deeper compressive events are related to the activity of both a major basement thrust that connects at surface with the pede apenninic thrust front and a major moho structure

subsidence rates in the po plain northern italy the relative impact of natural and anthropogenic causation abstract the central eastern po plain in northern italy is a rapidly subsiding sedimentary basin that hosts about 30 of the italian population and 40 of italy s total productive activities subsidence rates range from 0 to 70 mm year the maximum occurring in synclinal areas at the po delta and near bologna the minimum located at the top of buried probable tectonically active anticlines mirandola ferrara we show that modern subsidence is at least an order of magnitude higher than due solely to long term natural processes this implies that most subsidence in the po plain has been induced by human activities as previously noted we suggest that the main factor controlling modern subsidence is water withdrawal which was particularly intense during the second half of the 20th century coinciding with accelerating economic growth we also evaluate the impact of rapid subsidence on floods in low areas by comparing subsidence velocity maps with flood maps this shows that there is a clear cut correlation between flood frequency and rapid subsidence in contrast few floods occurred in low subsidence areas which generally correspond with the top of buried anticlines we finally note that the anthropic caused increase in subsidence has now greatly increased the potential for additional floodings

genetically related alluvial deposits across active fault zones an example of alluvial fan terrace correlation from the upper quaternary of the southern po basin italy integrated studies of alluvial fan systems and related intramontane valley deposits provide potentially useful tools for understanding the character of alluvial sedimentation and its control in fault controlled piedmont zones an example is reported from the uppermost quaternary alluvial deposits of the northern apennines and the southern margin of the po basin a distinctive cyclicity characterizes both the outcropping and the buried units in the study area in intramontane valleys individual cycles consist of regular alternations of sections displaying high and low terrace preservation in the subsurface a rhythmic alternation of coarse grained bodies and laterally extensive pelitic horizons occurs at various scales and represents the basic cyclic motif of the depositional system the correlation between the terrace sequences and the depositional cycles in the subsurface allows the differentiation of distinct sequences with a characteristic internal architecture in the lower part of sequences poorly preserved terrace deposits are laterally correlatable with alluvial fan gravel bodies whereas highly preserved terrace deposits are correlated laterally with predominantly floodplain sediments in the upper part of sequences reliable correlation lines have been constructed using 14c dating thrust tectonics and climate exerted a major control on sequence development deep valley excavation with subsequent low terrace preservation occurred in response to relief rejuvenation during successive thrusting events on the other hand decreasing erosion related to periods of minor tectonic activity led to terrace preservation in the intramontane valleys the coeval episodes of alluvial fan growth and abandonment recorded at the basin margin are interpreted to reflect changes in the efficiency of the drainage system due to variations of tectonic uplift in the adjacent areas alternating phases of deglaciation and renewed glaciation however are inferred to have played a major role in controlling the amount and type of sediment delivered to the alluvial fan complexes

mathematical simulation of the subsidence of ravenna land subsidence at ravenna is the result of aquitard and reservoir compaction caused respectively by extensive groundwater withdrawals from the unconsolidated quaternary basin and gas production from a number of pre quaternary pools scattered over the area water pumpage paralleled the postwar industrial development of ravenna until the middle seventies when consumption was drastically curtailed owing to the economic crisis and the activation of a new aqueduct gas production started in 1952 the exploitation of several reservoirs is currently under way and the search for new fields is still in progress geodetic records indicate that the maximum cumulative subsidence over the period 1950 1986 including a natural geologic settlement of perhaps 2 mm yr has been 1 30 m in the industrial zone of ravenna in 1980 the municipality promoted a reconnaissance study with the primary aim of providing the information base needed to reconstruct the actual occurrence understand correctly the physical behavior and produce the essential input data to a mathematical model which realistically relates the subsidence of the city to groundwater withdrawal and gas removal with an emphasis on their respective influences the results from the three dimensional numerical simulations performed with the aid of mixed finite element finite difference and integral models show that the primary responsibility for the regional land sinking should be placed on the subsurface water overdraft which occurred until the middle 1970s gas withdrawal plays a role restricted to the area overlying each reservoir with a magnitude depending on the depth of burial thickness of mineralized rocks and overall volumetric production a major environmental impact may be expected where the gas subsidence bowl is intersected by the adriatic coastline

quantitative evidence that compaction of holocene sediments drives the present land subsidence of the po delta italy 1 deltas are highly dynamic coastal systems that over the last few decades have generally experienced a substantial area loss caused by trapping of river sediments in upland drainage basins as well as land subsidence due to natural and anthropogenic causes a major example is the po delta in the mediterranean in northeastern italy this area has experienced as much as 3 m of land subsidence from the 1930s to the 1970s primarily because of the extraction of gas bearing waters however present subsidence rates are largely unknown and the ground settlement is supposedly controlled by natural long term deep processes we have combined radar interferometric point target analysis ipta with previous geomorphological investigations on aerial satellite images and seismic surveys and geochronological data from core samples and geomechanical in situ tests to assess the current sinking of the delta and to understand the processes controlling the vertical movement the high density of the measurable point targets more than 15 000 allows characterization of the spatial variation in the vertical land motions vlm ranging from 1 to 15 mm yr we find that subsidence rates are significantly correlated with the age of highly compressible holocene deposits that compose the shallowest 30 40 m of the sedimentary sequence a typical log type consolidation equation applicable at the scale of the entire delta has been obtained we conclude that the consolidation of late holocene sediments is the major cause of the present land subsidence in the po river delta this finding has significant impact on the understanding of many other modern deltas that were formed in the lower holocene epoch

vertical gps ground motion rates in the euro mediterranean region new evidence of velocity gradients at different spatial scales along the nubia eurasia plate boundary we use 2 5 to 14 years long position time series from 800 continuous global positioning system gps stations to study vertical deformation rates in the euro mediterranean region we estimate and remove common mode errors in position time series using a principal component analysis obtaining a significant gain in the signal to noise ratio of the displacements data following the results of a maximum likelihood estimation analysis which gives a mean spectral index 0 7 we adopt a power law white noise stochastic model in estimating the final vertical rates and find 95 of the velocities within 2 mm yr with uncertainties from filtered time series 40 smaller than from the unfiltered ones we highlight the presence of statistically significant velocity gradients where the stations density is higher we find undulations of the vertical velocity field at different spatial scales both in tectonically active regions like eastern alps apennines and eastern mediterranean and in regions characterized by a low or negligible tectonic activity like central iberia and western alps a correlation between smooth vertical velocities and topographic features is apparent in many sectors of the study area glacial isostatic adjustment and weathering processes do not completely explain the measured rates and a combination of active tectonics and deep seated geodynamic processes must be invoked excluding areas where localized processes are likely or where subduction processes may be active mantle dynamics is the most likely process but regional mantle modeling is required for a better understanding

influence of water and sediment supply on the long term evolution of alluvial fans and deltas statistical characterization of basin filling sedimentation patterns 1 the temporal and spatial variability of sedimentation resulting from sediment storage and release and the lateral mobility of sediment transporting flows imparts fundamental patterns into the stratigraphic record recent studies show that paleoenvironmental allogenic signals preserved in stratigraphy may be contaminated by internally generated autogenic sedimentation patterns however it is unclear how the magnitude of autogenic dynamics is related to allogenic forcings utilizing statistical methods we quantify basin filling trends in three laboratory experiments where input water and sediment flux were varied we use the compensation index and compensation time scale to estimate the strength of compensation defined here as the tendency to fill topographic lows faster than would result from random deposit stacking and to estimate the time scales over which autogenic processes operate in the experiments topography of channelized deltas formed by noncohesive sediment was monitored in a basin experiencing temporally and spatially uniform relative subsidence each experiment resulted in construction of a stratigraphic package in excess of 25 channel depths thick we find that compensation strength in the experiments is not influenced by absolute magnitudes of water and sediment flux but does increase as a function of the ratio of water to sediment flux a compensation time scale defined as the maximum depth of a system s channels divided by the long term deposition rate accurately defines the maximum time scale at which autogenic dynamics occur in all experiments when applied to field scale systems we predict that autogenic dynamics occur out to time scales between 5 and 150 kyr

isotopic features of emilia romagna region north italy groundwaters environmental and climatological implications 18o 16o d h tritium and carbon isotopes were analysed together with the main geochemical parameters of selected wells of groundwaters in the emilia romagna region the isotope data collected in a three year monitoring program of surface waters allowed a subdivision of the studied region within the main feeding areas of the po and apennine rivers the isotopic investigation demonstrated the existence of palaeowaters hosted in deep aquifers in the plains and their overexploitation which induced land subsidence phenomena groundwater stable isotopes have been utilized as a proxy for temperature and have shown significant atmospheric temperature variations over the past 30 000 years

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

multiple processes causing sea level rise in the central mediterranean our analysis of a series of sea level records along the italian coast of the adriatic sea indicates a sea level rise not attributable to a global eustatic signal but rather to the combined effects of active tectonics and glacial isostatic adjustment henceforth gia the highest predicted sea level rise of the order of 0 9 1 0 mm yr occurs in proximity of the city of ravenna in the northern sector of the adriatic sea decreasing to 0 4 0 5 mm yr in the northernmost and southern parts of the adriatic sea while gia is the dominant mechanism of sea level rise in the southern sector of the adriatic sea active tectonics and gia contribute a comparable amount in the north our results are of importance for quantitative estimates of trends of sea level changes in a part of the mediterranean the northern adriatic sea where the historical cities of venice and ravenna are severely exposed to sea level rise

grain size of fluvial deposits and late quaternary climate a case study in the po river valley italy by stacking the grain size data interpreted from many logs of borings down to 200 m deep in a sector of the po river valley we have obtained a curve of the clay silt fraction vs depth that matches the oxygen isotope curve of paleotemperatures for the late quaternary contour maps and plots for selected subzones show that the northern half of the study area is characterized by this correlation whereas the southern part adds only a random low amplitude noise to the curve the suggested dependence of grain size of fluvial deposits on climate in a part of the study area would provide an indirect way to date these not otherwise datable sediments allowing an evaluation of the sedimentation rates and of the total subsidence since the last interglacial

spatial analysis of land subsidence induced by groundwater withdrawal abstract a comprehensive study of the factors influencing magnitude and distribution of ground settlements observed during the second half of the twentieth century in the area of bologna italy is presented to derive a unified framework useful for interpreting the observed phenomena and for predicting future scenarios information collected over a surface of more than two hundred square kilometres includes previous geological studies hydro geological geotechnical and topographical investigations carried out with various purposes the geological features of the whole region have been initially reviewed to figure out the local geological and hydro geological setup then the stratigraphic sequence has been obtained by integrating the results of an extensive campaign carried out over the whole region for water exploitation the mechanical characterization of the soil has been based on geotechnical tests performed in the area for the construction of new transportation infrastructures groundwater levels periodically recorded on a distributed net of wells have been interpreted with a two dimensional seepage model capable of back calculating the modification of the groundwater regime induced by water withdrawal the spatial and temporal distributions of settlements have been derived by combining sequential topographical monitoring campaigns covering a period of about sixty years with satellite records to simultaneously analyse all information and provide an interpretation of the observed phenomena all data have been collected in a geographical information system interpolating the measured data with a geostatistical method in such a way the role of the different factors has been captured finding a logical correlation between land subsidence subsoil composition and groundwater withdrawal and a strategy has been traced which can be exported to the analysis of other similar situations

on postglacial geoid subsidence over the equatorial oceans we develop two new spectral formalisms for the gravitationally self consistent solution of the sea level equation which governs the redistribution of glacial meltwater on a visco elastic earth the first is a purely spectral technique based on an extension of theory outlined by dahlen 1976 for determining the equilibrium oceanic tide on an elastic planet using this technique with a feasible spherical harmonic truncation level l 30 we can obtain convergence in the computed sea level variations within the degree range l 10 we also develop a second pseudospectral technique however which permits the construction of gravitationally self consistent solutions to much higher degree and order l 100 the pseudospectral formalism is employed here to develop a comprehensive physical explanation for the global pattern of present day sea level variations due to ongoing glacial isostatic adjustment in particular we focus upon a mechanism which we term equatorial ocean syphoning that acts to draw water toward the oceanic portion of the collapsing peripheral bulge that encircles previously glaciated regions the collapse of the forebulge induces a flow of water which is required to maintain hydrostatic equilibrium the syphoning mechanism dominates the relative sea level rsl variation in oceans in the far field of the ice sheets that is beyond the peripheral bulge during periods such as the interglacial of the past 4000 years during which the volume of the ice sheets has not apparently changed appreciably while at the same time isostatic adjustment persists the rsl change in the near field is in contrast dominated by the local vertical displacement of the solid surface finally comparison of gravitationally self consistent predictions of rsl change in the far field with the observational data at small pacific island sites has provided an upper bound of 1 to 2 m for the eustatic sea level rise produced by any recent last 3000 years melting of the antarctic ice sheet

stratigraphic control on earthquake induced liquefaction a case study from the central po plain italy abstract studies on earthquake induced liquefaction tied to high resolution stratigraphic analysis have been rarely undertaken we report the results of a multidisciplinary study from the quistello moglia area in the central po plain northern italy in this region combined stratigraphic sedimentological geotechnical and geochemical data allowed assessment of liquefaction potential and identification of the primary source for liquefaction following the second main shock mw 6 of the 2012 po plain earthquake using cone penetration test cpt based simplified procedures for liquefaction hazard evaluation we assessed the highest liquefaction potential of holocene fluvial channel and related crevasse levee fine sand silt facies encased in thick mud prone floodplain and swamp successions the liquefaction potential and the intensity of the manifestations induced on the ground surface decreased for the vertically amalgamated sheet like pleistocene sandy fluvial units encountered at depths greater than 13 m floodplain and swamp deposits were virtually non liquefiable in the quistello area the compositional characterization of sands that were liquefied and extruded during the 2012 earthquake reveals the diagnostic geochemical fingerprint of sediment carried by the po river as opposed to the apennine composition of surficial sediments these data rule out proximity of liquefied layers to the surface and attest the buried meandering po river system at depths of 7 10 m most likely representing the source for the liquefied sand that vented to the surface similarly at moglia liquefied sands were likely sourced from loose and saturated ribbon shaped fluvial sand bodies encased in mud though at shallower 4 7 m depths pronounced liquefaction phenomena in alluvial plain systems are commonly believed to be associated primarily with elongate topographic ridges following paleo river courses here we document that under favorable stratigraphic conditions liquefaction may also occur away from surficial channel levee systems in areas dominated superficially by overbank fines combining subsurface stratigraphic analysis with geotechnical data thus is critical to investigate liquefaction patterns and delineate liquefaction hazard zones

identification of potential subsidence related to pumping in the almeria basin se spain ground subsidence of detrital deposits in the almer ia basin se spain was studied using the remote sensing technique of differential interferometry sar dinsar this basin is one of the most arid in europe receiving an average rainfall of 250 mm per year over the last 60 years the region has experienced an enormous agricultural and urban expansion whose water demand has been largely supplied from groundwater leading to the current situation of overexploitation of water resources this paper outlines the likely relationship between groundwater abstraction and subsidence to this end 34 ers and envisat images taken between 2003 and 2009 were analysed to estimate ground surface deformations and hence compared with water table variations measured in a number of piezometers in the basin the analysis shows a clear parallelism between the variations in piezometric level and deformation of the ground surface in addition the zones of greatest subsidence coincide with those areas where groundwater abstractions are concentrated subsidence over the examined period varies from 10 to 30 mm with extreme values as high as 50 mm which translates to a rate of between 1 7 and 5 mm year reaching maximum rates of 8 mm year at some points given such subsidence rates damage to urban infrastructures are for the moment incipient

post depositional subsidence of the avellino tephra marker bed in the pontine plain lazio italy implications for early bronze age palaeogeographical water level and relative sea level reconstruction abstract land subsidence has played and is still playing a significant role in coastal wetlands worldwide and in palaeogeographical reconstructions of such wetlands the varying thickness of compaction prone sediments over a stable subsurface is a key factor in determining its magnitude and in locating the most affected areas in the coastal low lying agro pontino lazio italy subsidence of the past 90 years has been mapped using historical elevation data due to the fortunate preservation of distal avellino tephra av tephra ca 1900 cal bce within its marshy strata discovered a decade ago detailed palaeogeographical reconstruction of the landscape in preparation for an assessment of its land use suitability in the early bronze age eba was possible current altitude variations of water lain tephra in lake areas assumed to be connected necessitated a closer look at its original deposition altitude and the role of post depositional subsidence recent subsidence patterns proved very useful for distinguishing stable from subsidence prone areas two different eba palaeo lake environments are distinguished an inland and a near coastal lake the av tephra altitude variation within these lakes partly marks differential post depositional subsidence within these lakes calculation of initial ripening of tephra bearing lake deposits on top of shallowly buried pleistocene ridges allowed for an estimation of original tephra deposition altitudes and associated lake levels for the inland lake a wide lake edge zone between 0 5 and 2 m above current sea level m asl was reconstructed where eba habitation or land use was possible at the near coastal lake a water level of 1 5 to 1 3 m asl at the time of av tephra deposition was constrained because tephra deposition occurred here just after marine influence ceased this altitude range is proposed to be a relative sea level rsl index point at the time of av tephra deposition the altitude range is in agreement with rsl models for tectonically stable areas in this region the importance of subsidence in palaeogeographical water level and rsl reconstructions in the region is stressed

persistent scatterer interferometry analysis of ground deformation in the po plain piacenza reggio emilia sector northern italy seismo tectonic implications

natural and anthropogenic factors affecting freshwater lenses in coastal dunes of the adriatic coast abstract this study characterizes the near shore portion of the shallow coastal aquifer included in the ravenna area northern italy with special attention to the roles of coastal dunes as freshwater reservoirs and their buffer on groundwater salinity the paper focuses on the presence and evolution of freshwater lenses below coastal dunes and highlights the existing differences between preserved natural dunes and dunes strongly affected by human intervention the influence that multiple natural and anthropogenic factors such as land cover local drainage network and beach erosion have on the presence size and evolution of the freshwater lenses in the aquifer is quantified and discussed the methodology includes multiple seasonal monitoring and sampling campaigns of physical water level salinity and temperature and chemical major cations and anions groundwater parameters results indicate that freshwater lenses where existing are limited in thickness about 1 2 m proximity to drainage ditches as well as limited dune elevation and size do not allow the formation and permanent storage of large freshwater lenses in the aquifer below the dunes the pine forest land cover that replaced the typical bush or sand cover intensifies evapotranspiration reducing net infiltration and freshwater storage the cation species distribution in the water shows that a freshening process is ongoing in preserved natural sites with stable or advancing beaches whereas a salinization process is ongoing in anthropogenic impacted areas with strongly fragmented dune systems currently the thin freshwater lenses in the shallow ravenna coastal aquifer are limited in space and have no relevance for irrigation or any other human activity the dune beach system however is the recharge zone of the coastal aquifer and its protection is important to reduce water and soil salinization which in turn control the health of the whole coastal ecosystem

geochemistry of the formation waters in the po plain northern italy an overview abstract the po valley brines represent the base level of the quaternary aquifer located in a thick clay sands sedimentary sequence geochemistry indicates that these are marine waters evaporated to the stage of gypsum precipitation and trapped at the bottom of the basin in the late messinian most of the groundwater samples collected from different springs and wells in the plain result from a mixture of these na cl brines and shallow groundwaters laterally recharged by the alpine and apennine chains natural outflows of brackish waters are associated with major tectonic features mud volcanoes located in the eastern sector of the po plain are constantly monitored as sudden chemical changes are significant precursors of seismic activity in the western sector calcite filled veins isotopically record different degrees of water rock interaction these are outcropping fossil conduits where mixing between shallow groundwaters and deep seated brines has occurred the temporal continuity of the hydrological circuits allows the reconstruction of past and present groundwater circulation patterns this paper summarises and integrates the geochemical data produced over many years in order to obtain a regional picture of brine origins and the natural mechanisms of groundwater flow

two and three dimensional numerical simulations of the stress field at the thrust front of the northern apennines italy 1 two and three dimensional mechanical models simulating the seismic cycle along thrust faults are devoted to the active front of the northern apennines buried under the plio pleistocene sediments of the eastern po plain the models aim at understanding two peculiar characters of the stress field in the region 1 analyses of borehole breakouts and other well data integrated with seismological information and field evidence show along depth variations from extensional to strike slip to compressional for increasing depth of the stress style along the active mirandola anticline and 2 seismic and borehole breakout data suggest strong lateral rotations of the stress axes along the frontal and lateral ramp portions of the mirandola thrust fault modeling results allowed us to understand that the mechanical decoupling along faults strongly affects the stress distribution in their vicinity under the form of strong rotations of the principal stress axes as a consequence the slip either fast or slow along active blind thrust faults could drive to local stress fields very different from that associated with regional tectonics this could explain together with other processes such as differential compaction the along depth variation of the stress field observed in the mirandola region and the strong lateral rotations of the principal stress axes observed along the lateral ramp of the mirandola thrust fault finally the seismic activity along one of the thrust fault ramps along the apennines front should not interfere with the state of stress along adjacent ramps

sea level and subsidence data from a late holocene back barrier lagoon valle standiana ravenna italy abstract late holocene back barrier sediments have been studied in a former lagoon reclaimed during the last century several shallow boreholes were cored from which nine organic rich samples were selected for radiocarbon dating and others for palynological and palaeontological analysis this enabled the reconstruction of the evolution of a back barrier coastal basin during the late holocene coastline progradation since late roman times the rate of relative sea level rise rslr has increased from 1 1 mm yr to over 2 mm yr even after removal of the main human impacts during of the last century this change is ascribed to sediment compaction related to changes in the hydrological regime and possibly to an isostatic subsidence wave accompanying the northward shift of the po delta during the last 2000 years

geomorphological map of the po plain italy at a scale of 1 250 000 a 1 250 000 scale map of the po plain northern italy has been produced by a team of 11 geomorphologists from several italian universities and other scientific institutions their coordinated work in producing the map started in 1986 and was organized through a consortium of 10 local groups the map provides a detailed classification of landforms based on morphogenetic criteria and has a clear morphographic content together with some morphometric elements the temporal evolution in regional landform patterns is not directly evidenced by the legend but may be interpreted through examination of relic surfaces river beds and beach ridges represented on the map the map also highlights the effects of human impacts on the evolution of the river system and coastal zone this paper chronicles the mapping process and presents the geomorphological basis for production of the map itself it uses extracts from the map to illustrate the major points and provides interested readers with information on how to obtain the complete map copyright 1999 john wiley sons ltd

post breakup evolution of the namibian margin constraints from numerical modeling abstract the namibian margin evolution started 130 myr ago after the breakup between south america and southern africa today it shows specific features i an elevation and a bathymetry about 1000 m higher than the surrounding areas ii a significant sediment supply during the late cretaceous following the first sedimentary peak that occurred during rifting and just afterwards and iii a long term progradation since the mid cretaceous this present configuration results in couplings between several processes and the inherited structure we constrained this evolution using a numerical simulation applied both onshore and offshore integrating different couplings i a thermal adjustment of a lithosphere driven by conductivity ii a flexural isostasy and iii the loading unloading effects of surface matter transfer three processes were investigated rock uplift a change in the erosion efficiency and a sea level fall the results were compared to some pertinent observations made on the namibian margin such as the vertical displacements the sediment transfers the denudation and the stratigraphic architecture in the marginal basin in each simulation rift related reliefs were rapidly relaxed resulting in an exponentially decreasing denudation and sediment accumulation sixty myr after the breakup we simulated an additional uplift an increase in the transfer efficiency of the sediment and a sea level fall the subsidence increased by loading inducing a new progradational trend nonetheless the three types of events differed in the duration of this progradation trend the larger the additional uplift the longer the progradation the transfer efficiency increase and sea level fall only resulted in a transient progradation trend from these results we suggest that the post rift evolution of the namibian margin was associated during the upper cretaceous to the rejuvenation of its continental relief triggered by a climate change during the turonian and by a slow long term rock uplift during the cenozoic

geochemistry of heavily exploited aquifers in the emilia romagna region po valley northern italy more than 5 800 chemical analyses on water samples collected during 1987 1995 from 528 monitoring wells located in the southernmost part of the po valley emilia romagna region northern italy one of the most urbanized industrialized and agriculturally developed areas of italy have been processed the analysis of data showed that 1 waters are discharging from both confined and unconfined aquifers 2 the water in the unconfined aquifer s is ca mg hco3 in composition while confined ones are na cl and or na hco3 3 both confined and unconfined aquifer samples have 18o and d isotopic values of meteoric signature 4 waters from both the aquifers are at least 40 years old 5 the pumping rate has caused subsidence particularly where the aquifer s is are unconfined 6 the unconfined aquifer s is exposed to the risk of no3 pollution 7 considering the present pressure i e pumping rate on this natural environment by human activity care must be taken in the future to preserve this strategic resource

integration of gnss and satellite insar data derivation of fine scale vertical surface motion maps of po plain northern apennines and southern alps italy global navigation satellite system gnss and satellite synthetic aperture radar sar interferometry represent the most important space geodetic techniques usually exploited to measure millimetric ground deformation on earth surface at both local and wide area scale sar images processed with persistent scatterers interferometry psi multitemporal approach lack of an absolute reference datum in this paper sar images are calibrated with data derived from permanent gnss stations in order to obtain absolute and more accurate displacement values the method used to correct psi with gnss is based on existing methodologies commonly applied in the geodetic practice of combining crustal and local deformation studies with geospatial statistical analysis the spatial distribution of vertical terrain deformations and their temporal changes are coherently measured leading to a fine scale surface velocity map in the central eastern po plain northern apennines and southern alps in italy the results reveal significant subsidence rates on the north western adriatic coast including the po delta and the lagoon of venice as well as on bologna and ferrara cities in agreement with long term displacement motion values provided by geological data and other previous works performed at local scale this paper demonstrates the importance and effectiveness in creating a single unique surface motion map by merging different data sets in which geodesy plays a relevant role in the datum alignment of psi products before the stacking of the sar maps

present day post glacial sea level change far from the late pleistocene ice sheets implications for recent analyses of tide gauge records we examine the sensitivity of predictions of the present day rate of sea level change due to glacial isostatic adjustment gia in two regions located within the far field of the late pleistocene ice sheets europe north africa and the western pacific caribbean to variations in the mantle viscosity profile the regions considered here encompass the location of 11 of 21 sites used in a recent determination based on gia corrected tide gauge records of the global rate of secular sea level change our analysis suggests that the mean gia correction at the 11 far field sites may vary by as much as 0 5 mm yr depending on the adopted earth model and we derive a bound on the residual secular sea level rise of 1 1 to 1 6 mm yr this bound is consistent with our analysis of the tide gauge record from the u s east coast and it suggests that previous estimates of the residual sea level rise represent an upper bound