pleistocene raised marine deposits of the cap bon peninsula n e tunisia records of sea level highstands climatic changes and coastal uplift abstract morphostratigraphic and sedimentological studies were undertaken in the cap bon peninsula north eastern tunisia these studies have identified a series of middle to late pleistocene age marine deposits discontinuously cropping out on three raised platforms pf i pf ii and pf iii these stepped marine platforms terraces were related to the interplay between pleistocene sea level changes and progressive uplift movement during quaternary period we present here a description of facies organization and stratigraphic characteristics of the platform deposits and their relation with eustatic and climatic variations all the marine platforms unconformably overlie a mio pliocene and quaternary slope succession the sedimentary sequences represented by mixed carbonate and siliciclastic bodies are related to the succession of highstand shorelines and contrasting climate conditions the intercalated soils and calcretization occurred during episodes of relative sea level fall the oldest platforms pf i and pf ii found at an elevation of about 100 m and 60 m respectively have so far no equivalent in the northern in the eastern or in the southern coasts of tunisia they are correspondingly attributed to mis 11 13 and mis 9 11 the youngest and lowest platform pf iii attains an altitude of 40 m and shows three high frequency cycles of sea level rise and fall probably associated with marine isotope stage mis 5e and mis 7

a high relative sea level stand in the middle holocene of southeastern tunisia abstract study of the marine holocene deposits in southeastern tunisia shows bioclastic beaches at elevations ranging between 0 and 100 cm above high tide level a h t l depending on the elevation of these fossilized shorelines the ages obtained are different the age of the older deposits ranges between 5900 and 4000 14cc yr b p 6400 4300 calendar yr b p there deposits consist of bioclastic beaches attaining an elevation of about 40 to 100 cm a h t l the younger deposit is dated at around 2100 14c years ago 1850 calendar yr b p and is found today at the same elevation as the present sea level this deposit also consists of bioclastic beach material and contains pottery fragments postglacial melting should not be responsible for this observed higher relative sea level stand because deglaciation ended about 7000 6000 14c years ago fairbanks 1989 furthermore the regularity of the paleobeach deposit elevation over a broad area in southeastern tunisia suggests that tectonics cannot explain the emergence the emergence of up to 1 m of marine deposits dating back to between 5900 and 4000 14c yr b p should rather be interpreted as the result in the region of a postglacial hydro isostatic rebound as predicted in the theological models of continental margins by for example clark et al 1978 and lambeck 1993 the present situation was reached 2100 14c years ago

statistical relationships between enhanced polar cap flows and pbis 1 poleward boundary intensifications pbis are auroral intensifications along the poleward boundary of the auroral oval and occur during all levels of geomagnetic activity however little is known about the triggering of pbis recent case studies have indicated the existence of longitudinally localized flow channels in the polar cap near and directed toward the nightside open closed field line boundary just before pbis motivated by these studies we analyze 115 events of coordinated observations by the time history of events and macroscale interactions during substorms all sky imager and super dual auroral radar network hf radar at rankin inlet to determine if this polar cap flow pbi relationship is commonly observed we start with isolated and intense pbis and examine the probability of them being associated with equatorward directed polar cap flows our results show the association to be frequent 90 with one to one correlations occurring in 50 of events considering the limitations of the radar observations this result indicates that pbis are commonly correlated with polar cap flow channels directed toward and then traversing the open closed field line boundary the flows statistically occur 1 2 min before the pbi initiations and the duration and width of the flows are comparable to those of the pbis we also perform a reverse study by starting with isolated polar cap flows and obtain similar results the remarkably high occurrence of association between enhanced polar cap flows and pbis indicates that enhanced mesoscale flows within the open field line region that traverse the open closed field line boundary are an important driver of pbi formation

kinematics of the western africa eurasia plate boundary from focal mechanisms and gps data summary the western mediterranean displays a complex pattern of crustal deformation distributed along tectonically active belts developed in the framework of slow oblique plate convergence we used earthquake and global positioning system gps data to study the present day kinematics and tectonics of the africa eurasia plate boundary in this region crustal seismicity and focal mechanisms analysed in terms of seismic moment release and seismic deformation outline the geometry of major seismic belts and characterize their tectonics and kinematics continuous gps data have been analysed to determine euler vectors for the nubian and eurasian plates and to provide the global frame for a new mediterranean gps velocity field obtained by merging continuous and campaign observations collected in the 1991 2005 time span gps velocities and displacements predicted by the nubia eurasia rotation pole provide estimates of the deformation accommodated across the tectonically active belts the rather simple deformation occurring in the atlantic region characterized by extension about perpendicular to the middle atlantic and terceira ridges and right lateral motion along the gloria transform fault turns into a complex pattern of deformation occurring along broader seismic belts where continental lithosphere is involved our analysis reveals a more complex fragmentation of the plate boundary than previously proposed the roughly e w trending mainly compressive segments i e southwestern iberia northern algeria and southern tyrrhenian where plate convergence is largely accomodated across rather localized deformation zones and partially transferred northward to the adjacent domains i e the algero balearic and tyrrhenian basins are interrupted by regions of more distributed deformation i e the rif alboran betics tunisia libya and eastern sicily or limited seismicity i e the strait of sicily which are characterized by less homogeneous tectonics regimes mainly transcurrent to extensional in correspondence of the observed breaks tectonic structures with different orientation interfere and we find belts with only limited deformation i e the high and middle atlas the tunisian atlas and the offshore tunisia libya belt that extends from the plate boundary into the nubian plate along pre existing tectonic lineaments our analysis suggest that the sicilian pelagian domain is moving independently from nubia according to the presence of a right lateral and extensional decoupling zone corresponding to the tunisia libya and strait of sicily deformation zone despite the space variability of active tectonic regimes plate convergence still governs most of the seismotectonic and kinematic setting up to the central aeolian region in general local complexities derive from pre existing structural features inherited from the tectonic evolution of the mediterranean region on the contrary along calabria and the apennines the contribution of the subducted ionian oceanic lithosphere and the occurrence of microplates i e adria appear to substantially modify both tectonics and kinematics finally gps data across the gibraltar arc and the tyrrhenian calabria domain support the hypothesis that slab rollback in these regions is mostly slowed down or stopped

evidence of relative sea level rise along the coasts of central apulia italy during the late holocene via maritime archaeological indicators abstract we investigated archaeological sites located along the coasts of central apulia italy to estimate the relative sea level changes which have occurred in this region since the bronze age and test the most recent model of predicted sea level for this region surveys focused on six sites located on both the adriatic and ionian coasts of apulia at the feet of the carbonatic murge plateau a tectonically stable zone as of the last 125 ka the sites present the remains of ancient settlements ranging from the bronze age circa ii millennium bc to the messapian and magna grecia age c 2 5 ka bp the roman c 2 ka bp and middle ages c 1 ka bp the archaeological sea level markers investigated in these sites provided new insight into the history of the relative sea level changes which have occurred in this region during the last c 3 3 ka bp data from 17 archaeological settlements from the above mentioned sites placed above or below the present sea level were analyzed the intervening relative sea level changes successive to their construction were estimated via the submergence of the functional elevations of significant architectural features related to the mean sea level at the time during which the settlements were functioning the r s l changes were estimated using detailed topographic surveys tide analyses and or hydrodynamic equations although not all archaeological markers allowed univocal interpretations r s l rise at about 2 25 0 20 m as of the bronze age and at least 0 90 0 20 m in the last 2 0 1 5 ka was estimated a comparison between the elevation of the marker and two different predicted sea level models seems to confirm a tectonic stability of the investigated region in the last c 3 3 ka bp

the submerged paleolandscape of the maltese islands morphology evolution and relation to quaternary environmental change after the end of the last glacial maximum 450 km2 of former terrestrial and coastal landscape of the maltese islands was drowned by the ensuing sea level rise in this study we use high resolution seafloor data multibeam echosounder data seismic reflection profiles and remotely operated vehicle imagery and bottom samples to reconstruct 300 km2 of this submerged maltese paleolandscape the observed paleolandscape is exceptionally well preserved and comprises former coastal landforms i fault related escarpments ii paleoshore platforms and associated shorelines iii paleoshoreline deposits and iv mass movement deposits and former terrestrial landforms v river valleys vi alluvial plains vii karstified limestone plateaus and viii sinkholes these elements indicate that the paleolandscape has been primarily shaped by tectonic activity combined with fluvial coastal slope instability and karstic processes these are the same processes the shaped the current terrestrial and coastal landscape by correlating the identified landforms with the timing of known changes in sea level during the last glacial cycle we infer that the alluvial plains and the shallowest limestone plateaus had up to 100 kyr to develop whereas the paleoshoreline deposits are likely to have formed between 28 kyr and 14 kyr the most prominent paleoshore platforms shorelines and river valleys were generated between 60 kyr and 20 kyr fluvial erosion is likely to have been prevalent during periods of low sea level last glacial maximum and stadial conditions during mis 3 whereas karst processes should have been more effective during warm and humid interstadial periods our results have implications for improving the characterization of past environments and climates as well as providing a much needed background for prehistoric and geoarcheological research in the central mediterranean region

elevation of the last interglacial highstand in sicily italy a benchmark of coastal tectonics well preserved mis 5 5 terraces in sicily are identified primarily by the index fossil strombus bubonius and dated by amino acid racemization aar electron spin resonance esr uranium thorium u th and thermo luminescence tl methods this review of published data and new results for the island of sicily and neighbouring small islands of egadi ustica and lampedusa identifies areas of rapid uplift in the east up to 175 m elevation above sea level slower uplift in the north 29 m and relative stability in the northwest 2 18 m in contrast about 250 km of the southern coastline of sicily does not appear to contain mis 5 5 outcrops in eastern sicily correlation of mis 5 5 highstands is based on strombus bubonius discovered at 86 m and correlated with the inner margin terrace at 110 m in the taormina area a fossiliferous marine conglomerate on a terrace with an inner margin at 115 m occurs in an area with undated terrace morphology and elevation data based on esr methodology applied to fossils sampled at 105 m in taormina we attribute this terrace to mis 5 probably 5 5 this age allows us to constrain the date of one point along a very long coastline that is otherwise undated a newly discovered fossil beach between 7 and 9 m at cefalu north central sicily attributed to mis 5 1 5 3 using aar analysis permits correlation of mis 5 5 to a 29 m high tidal notch geomorphologically related to a terrace at the same elevation cefalu lies in an important position between the uplifted coastline of northeastern sicily and the more stable coastline of western sicily this compilation of mis 5 5 data for all of sicily reflects the active tectonics of eastern sicily in contrast to the rest of the island

tidal notches in mediterranean sea a comprehensive analysis abstract recent works evelpidou et al 2012 suggest that the modern tidal notch is disappearing worldwide due sea level rise over the last century in order to assess this hypothesis we measured modern tidal notches in several of sites along the mediterranean coasts we report observations on tidal notches cut along carbonate coasts from 73 sites from italy france croatia montenegro greece malta and spain plus additional observations carried outside the mediterranean at each site we measured notch width and depth and we described the characteristics of the biological rim at the base of the notch we correlated these parameters with wave energy tide gauge datasets and rock lithology our results suggest that considering the development of tidal notches the consequence of midlittoral bioerosion as done in evelpidou et al 2012 is a simplification that can lead to misleading results such as stating that notches are disappearing important roles in notch formation can be also played by wave action rate of karst dissolution salt weathering and wetting and drying cycles of course notch formation can be augmented and favoured also by bioerosion which can in particular cases be the main process of notch formation and development our dataset shows that notches are carved by an ensemble rather than by a single process both today and in the past and that it is difficult if not impossible to disentangle them and establish which one is prevailing we therefore show that tidal notches are still forming challenging the hypothesis that sea level rise has drowned them

new insights on the relative sea level change during holocene along the coasts of tunisia and western libya from archaeological and geomorphological markers new data of sea level changes for the mediterranean region along the coasts of northern africa are presented data are inferred from archaeological sites of punic roman age located along the coast of tunisia between tunis and jerba island and along the western coast of libya between sabratha and leptis magna data are based on precise measures of presently submerged archaeological markers that are good indicators of past sea level elevation nineteen selected archaeological sites were studied in tunisia and four in libya all aged between 2 0 and 1 5 ka bp the functional elevations of significant archaeological markers were measured with respect to the sea level at the time of measurements applying corrections for tide and atmospheric pressure values the functional elevations of specific architectural parts of the sites were interpreted related to sea level at the time of their construction providing data on the relative changes between land and sea observations were compared against sea level change predictions derived from the glacio hydro isostatic model associated with the last glacial cycle the results indicate that local relative sea level change along the coast of tunisia and libya has increased 0 2 0 5 m since the last 2 ka besides minor vertical tectonic movements of the land the observed changes are produced by eustatic and glacio hydro isostatic variations acting in the mediterranean basin since the end of the last glacial maximum

submerged archaeological sites along the ionian coast of southeastern sicily italy and implications for the holocene relative sea level change abstract precise measurements of submerged archaeological markers in the siracusa coast southeastern sicily italy provide new data on relative sea level change during the late holocene four submerged archaeological sites have been studied and investigated through direct observations two of them are greek archaic in age 2 5 2 7 ka and are now 0 98 1 48 m below sea level the other two developed during the bronze age 3 2 3 8 ka and are now 1 03 1 97 m below sea level these archaeological data have been integrated with information derived from a submerged speleothem collected in a cave located along the siracusa coast at 20 m depth the positions of the archaeological markers have been measured with respect to present sea level corrected for tide and pressure at the time of surveys these data were compared with predicted sea level rise curves for the holocene using a glacio hydro isostatic model the comparison with the curve for the southeastern sicily coast yields a tectonic component of relative sea level change related to regional uplift uplift rates between 0 3 and 0 8 mm yr have been estimated

thermochemical flows couple the earth s inner core growth to mantle heterogeneity the uppermost 100 km of the earth s inner core is subject to an east west divide seismic waves travel more rapidly and are attenuated more severely in the eastern than in the western hemisphere and the west is more anisotropic that is seismic waves travel at different speeds in different directions than the eastern hemisphere the origin of this hemispherical dichotomy has remained enigmatic aubert et al now show that a model incorporating thermochemical convection and dynamo action can account for these effects by producing a large scale long term outer core flow that couples the heterogeneity of the inner core with that of the lower mantle seismic waves sampling the top 100 km of the earth s inner core have revealed that the eastern hemisphere is seismically faster more isotropic and more attenuating than the western hemisphere it is now shown that a single model of thermo chemical convection and dynamo action can account for all these effects by producing a large scale long term outer core flow that couples the heterogeneity of the inner core with that of the lower mantle seismic waves sampling the top 100 km of the earth s inner core reveal that the eastern hemisphere 40 e 180 e is seismically faster1 2 more isotropic2 3 and more attenuating4 than the western hemisphere the origin of this hemispherical dichotomy is a challenging problem for our understanding of the earth as a system of dynamically coupled layers previously laboratory experiments have established that thermal control from the lower mantle can drastically affect fluid flow in the outer core5 which in turn can induce textural heterogeneity on the inner core solidification front6 the resulting texture should be consistent with other expected manifestations of thermal mantle control on the geodynamo specifically magnetic flux concentrations7 8 in the time average palaeomagnetic field9 10 over the past 5 myr and preferred eddy locations11 in flows imaged below the core mantle boundary by the analysis of historical geomagnetic secular variation12 here we show that a single model of thermochemical convection and dynamo action can account for all these effects by producing a large scale long term outer core flow that couples the heterogeneity of the inner core with that of the lower mantle the main feature of this thermochemical wind is a cyclonic circulation below asia which concentrates magnetic field on the core mantle boundary at the observed location and locally agrees with core flow images this wind also causes anomalously high rates of light element release in the eastern hemisphere of the inner core boundary suggesting that lateral seismic anomalies at the top of the inner core result from mantle induced variations in its freezing rate

multiproxy assessment of holocene relative sea level changes in the western mediterranean sea level variability and improvements in the definition of the isostatic signal abstract a review of 917 relative sea level rsl data points has resulted in the first quality controlled database constraining the holocene sea level histories of the western mediterranean sea spain france italy slovenia croatia malta and tunisia we reviewed and standardized the geological rsl data points using a new multi proxy methodology based on 1 modern taxa assemblages in mediterranean lagoons and marshes 2 beachrock characteristics cement fabric and chemistry sedimentary structures and 3 the modern distribution of mediterranean fixed biological indicators these rsl data points were coupled with the large number of archaeological rsl indicators available for the western mediterranean we assessed the spatial variability of rsl histories for 22 regions and compared these with the ice 5g vm2 gia model in the western mediterranean rsl rose continuously for the whole holocene with a sudden slowdown at 7 5 ka bp and a further deceleration during the last 4 0 ka bp after which time observed rsl changes are mainly related to variability in isostatic adjustment the sole exception is southern tunisia where data show evidence of a mid holocene high stand compatible with the isostatic impacts of the melting history of the remote antarctic ice sheet our results indicate that late holocene sea level rise was significantly slower than the current one first estimates of gia contribution indicate that at least in the northwestern sector it accounts at least for the 25 30 of the ongoing sea level rise recorded by mediterranean tidal gauges such contribution is less constrained at lower latitudes due to the lower quality of the late holocene index points future applications of spatio temporal statistical techniques are required to better quantify the gradient of the isostatic contribution and to provide improved context for the assessment of 20th century acceleration of mediterranean sea level rise

vertical displacement trends in the aegean coastal zone ne mediterranean during the holocene assessed by geo archaeological data trends in the vertical displacement i e uplift or subsidence of the aegean sea coastal zone have been assessed by comparing observational data with those derived from the predictive glacio hydro isostatic model of lambeck and purcell 2005 for a period spanning from the mesolithic to the late roman times the data base comprises published studies that use both geomorphological with associated biological material and archaeological sea level indicators markers localities demonstrating uplift of high amplitude were detected in front of the hellenic arc antikythira crete rhodes nisyros and in the northeast aegean region thrace whilst areas experiencing tectonic subsidence were mainly observed in the central aegean region which is characterized by an extensional tectonic domain however regional scale tectonic particularities have caused uplift in parts of the west and east coast of central aegean tectonically stable sites can be found in the cyclades plateau however this is due to a bala

westward traveling surges sliding along boundary arcs and distinction from onset arc brightening 1 after onset auroral brightening rapidly spreads azimuthally along the onset arc typically but not always extending substantially farther westward than eastward expansion phase auroras also expand poleward and can contact an arc along the auroral poleward boundary for such events we find that poleward expansion of the region of active aurora accelerates after contact forming a bulge region that protrudes into the preexisting polar cap and expands westward as the westward traveling surge this westward motion is slower than and initiates later than the azimuthal spreading of the onset arc brightening the poleward boundary arc remains connected to the surge as the surge slides along the equatorward moving edge of the boundary arc and this connection appears to set off the westward traveling poleward protruding activity of the surge via localized polar cap flow adjacent to the boundary arc ground magnetic signatures show a relatively weak h component depression moving westward with the onset arc brightening and a delayed substantially larger depression moving with the westward propagating surge that must be associated with a substantially larger westward ionospheric current the clear distinction between onset arc brightening and the westward traveling surge seen in auroral and magnetometer current signatures implies that their underlying processes are very different evidence suggests that flow channels adjacent to the boundary arc possibly feed surge development these results are consistent with current wedge formation being more associated with post onset activity than with onset and with flow channels from the polar cap being important for surge bulge development

two dimensional structure of auroral poleward boundary intensifications 1 we investigate the two dimensional structure of auroral poleward boundary intensifications pbis pbis are a nightside auroral intensification that has been studied primarily with ground based meridian scanning photometers msps they have a signature that in the msp data appears as an increase in intensity at or near the magnetic separatrix and is often seen to extend equatorward they are also associated with fast flows in the tail and are thus important to the dynamics of the plasma sheet msp data provide information about the temporal evolution of the aurora in one spatial dimension in this case roughly along a magnetic meridian this paper is motivated by a desire to determine the physics of pbis that is revealed by their two dimensional structure to do this we have identified a number of pbi events in the canopus rankin inlet and gillam msps that occurred at times when high resolution two dimensional images of the aurora over the same region were also available the two dimensional images used in this study were obtained by the freja uv imager from october 1992 to january 1993 and by the canopus gillam all sky imager during the winter viewing season of 1996 1997 we find that pbis as observed by the msps are either equatorward extending or non equatorward extending equatorward extending pbis are either north south aligned structures or east west arcs propagating mostly equatorward but we were not able to determine without doubt which type is the most prevalent we suggest that equatorward extending pbis may be the auroral footprint of two major modes of energy transfer in the plasma sheet multiple narrow earthward fast flow channels in the plasma sheet and sequences of azimuthally broad and primarily earthward propagating phase fronts initiating near the separatrix nonequatorward extending pbis are found to mostly be a series of multiple bead like intensifications along the poleward boundary of the aurora zone such pbis may be evidence for shear instabilities at the separatrix boundary on the flanks of the magnetotail

millstone coastal quarries of the mediterranean a new class of sea level indicator abstract the coasts of italy still preserve several remnants of coastal quarries built in antiquity that now provide insights into the intervening sea level changes occurred during the last millennia in this paper we show and discuss a new class of sea level indicator consisting of millstones carved along the rocky coast of southern italy since 2500 bp that are currently submerged they were extracted from beachrocks sandstones or similar sedimentary rocks easier for carving by ancient carving tools our study focuses on 10 coastal sites located at capo d orlando avola and letojanni in sicily soverato tropea and capo dell armi in calabria castellabate palinuro and scario in campania and polignano san vito in apulia unfortunately only limited archaeological information is available for these anthropic structures scario one of these millstone quarries discussed here has been dated through independent archaeological remains allowing us to restrict the exploitation age to the end of xvii century present day elevations of these coastal sites were obtained through geo archaeological surveys calibrated using the nearest tidal stations together with geomorphological and tectonic interpretations data were compared against the latest sea level predictions based on glacio hydro isostatic models our results allow proposal of the age range of these millstone quarries and to estimate the intervening relative sea level changes since the time when they were carved

assessing vermetid reefs as indicators of past sea levels in the mediterranean abstract the endemic mediterranean reef building vermetid gastropods dendropoma petraeum complex dendropoma spp and vermetus triquetrus develop bio constructions rims on rocky shorelines at about mean sea level msl and are therefore commonly used as relative sea level rsl markers in this study we use elevations and age data of vermetid reefs to 1 re assess the vertical uncertainties of these biological rsl indicators and 2 evaluate the vertical growth rates along a mediterranean east west transect in attempt to explain the differences found in both growth rates and uncertainties in israel differential global positioning system dgps and laser measurements relative to the local datum show that the reef surfaces mainly occupy the upper intertidal zone with variations in elevation from 0 51 0 07 m to 0 13 0 05 m along the coast however in specific sites the vertical uncertainty exceeds the tidal range in some places the local vermetid species d anguliferum and v triquetrus appear to alternate along the vertical rim profiles this study documents a spatial variability of vertical growth rates ranging from 1 mm yr 1 in israel and crete to 0 1 0 2 mm yr 1 in nw sicily and spain the order of magnitude of the difference in growth rates correlates with the east west spatial thermal gradient of sea surface temperature sst preferential skeleton deposition of d petraeum and v triquetrus measured by growth axis 18o analysis shows that most calcification occurs at sst above the mean annual value these findings indicate that vermetid reefs are a site specific rsl indicator displaying various vertical uncertainties and inner structure complexities local data on the indicative range of vermetids are required when reconstructing relative sea level changes using fossil vermetids

27 august 2001 substorm preonset phenomena two main onsets field aligned current systems and plasma flow channels in the ionosphere and in the magnetosphere we supplement the results of the 27 august 2001 substorm studied earlier in the series of papers described is the plasma flow in the nightside ionosphere from the near polar region from the polar cap to the auroral oval during the substorm preonset phase and two expansion onsets eo1 and eo2 produced by reconnection in the closed tail magnetic reconnection mr1 and in the open tail lobes mr2 respectively we discuss the location of the mr2 region is it near middle and or distant tail and the eo2 trigger mechanism the upward substorm current wedge field aligned current fac and the downward fac in the polar cap dusk sector that were both produced by different types of magnetosphere ionosphere feedback instability are found to provide the main contribution to the system of facs during eo1 and eo2 also we obtain the estimates for the eo1 and eo2 power and energy addressed are the variations in the tail lobe magnetic flux and their variations association with eo2 in addition we describe a 3 d system of mesoscale cells each of which involves a plasma vortex and a local fac maximum the cells of this system in the inner magnetosphere and in the tail lobes intensify one after other within 2 min interval at last we substantiate the assumption that the fast plasma flow recorded by the cluster satellites 7 min prior to eo1 was a bursty bulk flow from the most distant tail

substorm onset and expansion phase intensification precursors seen in polar cap patches and arcs 1 localized transient polar cap flows impinging on the poleward boundary of the nightside auroral oval have been suggested to precede poleward boundary intensifications pbis which are often followed by auroral streamers some of which propagate equatorward and appear to lead to substorm auroral onset while echo coverage often limits radar flow measurements imaging of polar cap patches and arcs has the potential to monitor localized polar cap flows by tracing emission structures previously associated with enhanced flows over long distances we use such imaging to examine if polar cap patches and arcs moving over large distances can be seen as possible precursors to presubstorm onset pbis we find evidence that such features which are longitudinally narrow propagate from the dayside polar region toward the nightside polar cap boundary prior to pre onset pbis this sequence indicates that transient activity in the dayside polar region may initiate polar cap patches and arcs that propagate across the polar cap and are followed by pre onset pbis furthermore we find evidence that expansion phase active aurora expanded poleward soon after additional polar cap patches and arcs reached close to the nightside polar cap boundary the expansion phase auroral activity significantly weakened when polar cap patches arcs disappeared our findings suggest that plasma transport originating from the dayside and reaching the nightside open closed boundary may trigger in plasma sheet flow bursts and play a crucial role in pre and post onset auroral activity polar cap imaging offers the possibility for monitoring such localized transient plasma transport over large distances

sea level change glacial rebound and mantle viscosity fornorthern europe northwestern europe remains a key region for testing models of glacial isostasy because of the good geological record of crustal response to the glacial unloading since the time of the last glacial maximum models for this rebound and associated sea level change require a detailed knowledge of the ice sheet geometry including the ice thickness through time existing ice sheet reconstructions are strongly model dependent and inversions of sea level data for the mantle response may be a function of the model assumptions thus inverse solutions for the sea level data are sought that include both ice and earth model parameters as unknowns sea level data from fennoscandia the north sea the british isles and the atlantic and english channel coasts have been evaluated and incorporated into the solutions the starting ice sheet for fennoscandia is based on a reconstruction of a model by denton hughes 1981 that is characterized by quasi parabolic cross sections and symmetry about the load centre both global northwestern europe as a whole and regional subsets of the data solutions have been made for earth model parameters and ice height scaling parameters the key results are as follows 1 the response of the upper mantle to the changing ice and water loads is spatially relatively homogenous across scandinavia the north sea and the british isles 2 this response can be adequately modelled by an effective elastic lithosphere of thickness 65 85 km and by an effective upper mantle viscosity from the base of the lithosphere to the 670 km depth seismic discontinuity of about 3 4 1020 pa s the effective lower mantle viscosity is at least an order of magnitude greater 3 the ice thickness over scandinavia at the time of maximum glaciation was only about 2000 m much less than the 3400 m assumed in the denton hughes model 4 the ice profiles are asymmetric about the centre of the ice sheet with those over the western part being consistent with quasi parabolic functions whereas the ice heights over the eastern and southern regions increase much more slowly with distance inwards from the ice margin

water load definition in the glacio hydro isostatic sea level equation abstract models of glacio hydro isostatic rebound and the concomitant sea level change have been progressively improved over the past three decades recently the procedures used by the group at the australian national university anu for the hydro isostatic component of the theory have been questioned quat sci rev 21 2002 409 although the details of the anu group s procedures have not been published because they are mainly computational in nature rather than representing significant conceptual advances because of this criticism we set out here in detail the procedures that have been used for the treatment of the migration of shorelines as sea levels rise and fall the effect of retreat and advancing grounded ice on shelves and shallow seas and the transitions from grounded to floating ice and vice versa we conclude that there is no basis for the criticism that these formulations and their implementation provide a high resolution and complete description of both sea level change and of the estimates of volumes of ice exchanged with the oceans the results from this formulation are confirmed by the entirely independent analyses of milne et al quat sci rev 21 2002 361 and mitrovica and milne geophys j int 2002 submitted for publication who conclude that our formulation is significantly more accurate than the procedure advocated by peltier science 265 1994 195 rev geophys 36 1998a 603 geophys res lett 25 1998b 3955

terminal antarctic melting inferred from a far field coastal site abstract the contribution of the antarctic ice sheet ais to deglacial sea level rise is poorly constrained this shortfall gives rise to concerns because incorrect ais estimates impact significantly on our ability to predict sea level change in the course of global warming given the scarcity of geological data and the complexity of the antarctic response to glacio isostatic adjustment processes there is a need for accurate data to constrain the timing of the ice sheet retreat here we provide such data on the holocene antarctic melting through an isolated geographic site on the northern hemisphere which we show is sensitive to the antarctic signal using both our site and other mid latitudinal relative sea level sites our model provides a consensus estimate that the ais released water corresponding to 5 m equivalent sea level at 8 ka and ceased melting at 6 ka this is different to most ais models which release an equal amount of water at 11 ka or after 6 ka our findings change model assumptions about the terminal ais melting and show that future holocene sea level research should focus on broad shelves and large coast embayments in the mid latitudes

history of subduction and back arc extension in the central mediterranean summary geological and geophysical constraints to reconstruct the evolution of the central mediterranean subduction zone are presented geological observations such as upper plate stratigraphy hp lt metamorphic assemblages foredeep trench stratigraphy arc volcanism and the back arc extension process are used to define the infant stage of the subduction zone and its latest back arc phase based on this data set the time dependence of the amount of subducted material in comparison with the tomographic images of the upper mantle along two cross sections from the northern apennines and from calabria to the gulf of lyon can be derived further the reconstruction is used to unravel the main evolutionary trends of the subduction process results of this analysis indicate that 1 subduction in the central mediterranean is as old as 80 myr 2 the slab descended slowly into the mantle during the first 20 30 myr subduction speeds were probably less than 1 cm year x1 3 subduction accelerated afterwards producing arc volcanism and back arc extension and 4 the slab reached the 660 km transition zone after 60 70 myr this time dependent scenario where a slow initiation is followed by a roughly exponential increase in the subduction speed can be modelled by equating the viscous dissipation per unit length due to the bending of oceanic lithosphere to the rate of change of potential energy by slab pull finally the third stage is controlled by the interaction between the slab and the 660 km transition zone in the southern region this results in an important re shaping of the slab and intermittent pulses of back arc extension in the northern region the decrease in the trench retreat can be explained by the entrance of light continental material at the trench

sea level change and vertical land movements since the last two millennia along the coasts of southwestern turkey and israel abstract this paper provides new relative sea level data inferred from coastal archaeological sites located along the turkish coasts of the gulf of fethye 8 sites and israel between akziv and caesarea 5 sites the structures selected are those that for effective functioning can be accurately related to sea level at the time of their construction thus their positions with respect to present sea level provide a measure of the relative sea level change since their time of construction useful information was obtained from the investigated sites spanning an age range of 2 3 1 6 ka bp the inferred changes in relative sea level for the two areas are distinctly different from a rise of 2 41 to 4 50 m in turkey and from 0 to 0 18 m in israel sea level change is the combination of several processes including vertical tectonics glacio hydro isostatic signals associated with the last glacial cycle and changes in ocean volume for the israel section the present elevations of the mis 5 5 tyrrhenian terraces occur at a few meters above present sea level and vertical tectonic displacements are small data from gps and tide gauge measurements also indicate that any recent vertical movements are small the mis 5 5 shorelines are absent from the investigated section of the turkish coast consistent with crustal subsidence associated with the hellenic arc the isostatic signals for the israel section of the coast are also small ranging from 0 11 mm yr to 0 14 mm yr depending on site and earth model and the observed eustatic average sea level change corrected for this contribution is a rise of 13 5 2 6 cm during the past 2 ka this is attributed to the time integrated contribution to sea level from a combination of thermal expansion and other increases in ocean volume the observed sea levels from the turkish sites in contrast indicate a much greater rise of up to 2 2 mm yr since 2 3 ka bp occurring in a wide area between knidos and kekova the isostatic signal here is also one of a rising sea level of up to 1 mm yr and site and earth model dependent and the corrected tectonic rate of land subsidence is 1 48 mm yr this is the primary cause of dramatic relative sea level rise for this part of the coast

holocene sea level change in malta abstract a multidisciplinary approach has been applied to study sea level changes along the coast of malta using data collected from underwater archaeological remains the elevation of archaeological markers have been compared with predicted sea level curves providing new bodies of evidence that outline the vertical tectonic behaviour of this region allowing estimation of the relative sea level changes that occurred in this area of the mediterranean since the bronze age during the roman age sea level was at 1 36 0 1 m while in the midde age it was at 0 56 0 2 m in agreement with previous estimations for the mediterranean region data indicate that malta was tectonically stable during the studied period the occurrence of the present day notch along the coasts of the island indicates recent vertical stability of the area the lack of mis 5 5 deposits all over the island could simply be due to high rates of erosion as its coasts are highly exposed to storm waves rather than tectonic movements however even very slight vertical movements could completely remove field evidence the relative stability of the maltese islands allowed a first attempt to provide a palaeoenvironmental reconstruction of its coasts at different time windows since the last glacial maximum the results have been used to infer time and mode of mammal dispersal to the island during the pleistocene

tracing sea level changes during the mid holocene in the southern mediterranean coast an example from the gulf of gabes abstract mid holocene sea level emergence was recorded along a mid latitude coastal site in the gulf of gabes tunisia in beach rock deposits however the post emergence sea level curve and associated hydro sedimentary processes have rarely been documented this study presents new records of sea level changes along the tunisian coast since the mid holocene each phase of the sea level curve was evidenced and supported by lithostratigraphic morphological and archaeologic markers post emergence sea level fall due to postglacial isostatic rebound was recognized in regressive sequences which vary depending on available accommodation space from a small pocket beach to a well developed dune system sea level stabilization following isostatic rebound has promoted the end phase deposits of the regressive sequences however this stability was interrupted during the late holocene by a high energy storm event that accumulated a transgressive boulder unit at 2 m above present shape and disposition of the boulder ridge behind a prograding modern shoreline suggests that sea level has not changed during the late holocene the existence of a roman fish pond on the upper foreshore confirms stability of sea level during the last two millennia the combination of lithostratigraphic morphological and archaeologic markers represents a tool for improving the accuracy of dating of erosional and depositional periods in mid coastal sections

sea level changes and geoarchaeology between the bay of capo malfatano and piscinni bay sw sardinia in the last 4 kys abstract the bay of malfatano cape is the berthing home to one of the most important maritime structures from the punic roman times in the mediterranean two opposing monumental structures have been preserved between 7 and 2 m due to rising sea level recent studies have identified the paleo sea level relating the eustatic component to the glacio hydroisostatic deformations this paper through stratigraphic palaeontological and geochronological data aims to trace the bay of capo malfatano s evolution in relation to the sea level rise during the last 4 kys based on data derived from geophysical surveys paleoshore lines have been redrawn and compared with data derived from coring in the inner part of the creek finally we evaluated the relationship between changes in palaeogeography and human settlements from the bronze age the breakwaters have been surveyed in detail using d gps techniques correlated to the geodesic 0 level through this data the shape of the breakwaters has been reconsidered and consequently the palaeo sea level has been re evaluated

new insights on the subsidence of lipari island aeolian islands southern italy from the submerged roman age pier at marina lunga abstract lipari island belongs to the aeolian archipelago located in the southern tyrrhenian sea italy which is one of the most active volcanic areas of the mediterranean basin although this region has been settled since prehistory only during roman times were coastal installations built in these islands in this study we present and discuss data on the relative sea level change estimated from a submerged pier of roman age dated 2100 100 bp this structure about 140 60 m is located along the coast of marina lunga corresponding to the present location of the main harbor of lipari island this pier which was accidentally discovered in 2008 during preliminary excavations for the construction of a new pier is a valuable indicator of relative sea level changes and vertical land movements its top surface is presently located at 9 1 0 05 m while the foundations at the outer end of the pier are at 11 6 0 05 m above a shoreline placed at 13 0 0 05 m we studied this site through direct archaeological investigations and ultra high resolution multibeam bathymetry the current submergence of this pier can be explained by the cumulative effect of the relative sea level changes caused by the regional glacio hydro isostatic signal active since the end of the last glacial maximum and the local volcano tectonic land subsidence from our investigations a relative sea level change at 12 3 0 7 m with a subsidence rate at 5 79 0 01 mm y 1 and an average value of volcano tectonic contribution at 5 17 0 01 m y 1 for the last 2100 100 years bp is estimated from comparison against the latest predicted sea level model for the southern tyrrhenian sea these rates of relative sea level change led to the disuse of the harbor after around the fourth century ad in agreement with archaeological interpretations our results provide new insights on the recent evolution of this active volcanic area

archaeological remains as sea level change markers a review abstract the mediterranean sea constitutes a unique basin from an historical and archaeological point of view as it has been a privileged way of communication for thousands of years for the people that dwelled on its shores their passage has left many traces on the seabeds in the areas where the ancient commercial routes passed and remains of structures where moorings havens or dwellings existed some of these structures nowadays submerged offer interesting indications aiding the reconstruction of the ancient coastlines this contribution aims to examine recent work in coastal geo archaeology targeting both 1 gathering and discussion of the data particularly those pertaining to the italian coasts and 2 commentary on the methodological debate and verification of the possibility of a protocol that may contain unequivocal referring elements to investigate the archaeological evidence currently underwater because of the relative sea level variations harbour infrastructures fishponds villae maritimae caves nymphaei private or public buildings or town quarters pre and protohistorical villages quarries caves etc a clear and more coherent methodological assumption may be needed the archaeological interpretation must initially establish the maritime and or harbour nature and vocation of the site determine its typology and specific usage analyze the elements of its building techniques that reveal themselves as meaningful markers of height or depth at the time of building and its functional elements the measure of the emerged part with respect to the average sea level and point out the time of construction its chronological range of usage frequentation the dynamics of its abandonment destruction obliteration the evaluation of both the height and functional depth to the mean sea level depends on the typology of the archaeological evidence its use and the local tide amplitudes the surface of a pier surely has a functional elevation different from that of a haulage area or a platea or a pavement

sea level in roman time in the central mediterranean and implications for recent change instrumental records indicate that ocean volumes during the 20th century have increased so as to raise eustatic sea level by f1 2 mm year and the few available records suggest that this is higher than for the previous century geological data indicate that ocean volumes have increased since the main phase of deglaciation about 7000 years ago but whether this continued into the recent past remains unclear yet this is important for establishing whether the recent rise is associated with global warming or is part of a longer duration non anthropogenic signal here we present results for sea level change in the central mediterranean basin for the roman period using new archaeological evidence these data provide a precise measure of local sea level of 1 35f0 07 m at 2000 years ago part of this change is the result of ongoing glacio hydro isostatic adjustment of the crust subsequent to the last deglaciation when corrected for this using geologically constrained model predictions the change in eustatic sea level since the roman period is 0 13f0 09 m a comparison with tide gauge records from nearby locations and with geologically constrained model predictions of the glacio isostatic contributions establishes that the onset of modern sea level rise occurred in recent time at f100f53 years before present d 2004 elsevier b v all rights reserved

coordinated superdarn themis asi observations of mesoscale flow bursts associated with auroral streamers 1 nightside auroral zone localized flow channels typically associated with auroral poleward boundary intensifications and streamers are an important component of high latitude ionospheric plasma dynamics we investigate the structure of these flow channels using two dimensional line of sight flow observations from the super dual auroral radar network superdarn radars and auroral images from the time history of events and macroscale interactions during substorms themis ground based all sky imager asi array radar echoes captured 500 km horizontal distance from the radars were mainly used to detect small scale flow structures that would otherwise be missed or poorly resolved in long range radar echoes after identifying 135 auroral streamers in the asi images at close radar capture locations we examined the associated ionospheric flow data in the radar echoes flow bursts and streamers are invariably correlated in all events the flow bursts are often directed equatorward and appear simultaneously with the streamers equatorward flows are located just to the east of the streamers less frequently 10 of the time a poleward flow enhancement was detected even when a streamer propagated equatorward the poleward flow enhancement being located to the west of the auroral streamer or to the east of the equatorward flow enhancement consistently with the spatial relationship between flow shear and upward field aligned currents in plasma sheet flow bursts the azimuthal width of the flow channel is on average 75 km and the azimuthal offset of the equatorward flow channel relative to the auroral streamer is 57 km eastward this study demonstrates the capability of radar imager pairs for identifying the 2 d structure of localized flows associated with plasma sheet flow bursts

sea level rise and potential drowning of the italian coastal plains flooding risk scenarios for 2100 abstract we depict the relative sea level rise scenarios for the year 2100 from four areas of the italian peninsula our estimates are based on the rahmstorf 2007 and ipcc ar5 reports 2013 for the rcp 8 5 scenarios www ipcc ch of climate change adjusted for the rates of vertical land movements isostasy and tectonics these latter are inferred from the elevation of mis 5 5 deposits and from late holocene sea level indicators matched against sea level predictions for the same periods using the glacio hydro isostatic model of lambeck et al 2011 we focus on a variety of tectonic settings the subsiding north adriatic coast including the venice lagoon two tectonically stable sardinia coastal plains oristano and cagliari and the slightly uplifting taranto coastal plain in apulia maps of flooding scenarios are shown on high resolution digital terrain models mostly based on lidar data the expected relative sea level rise by 2100 will change dramatically the present day morphology potentially flooding up to about 5500 km 2 of coastal plains at elevations close to present day sea level the subsequent loss of land will impact the environment and local infrastructures suggesting land planners and decision makers to take into account these scenarios for a cognizant coastal management our method developed for the italian coast can be applied worldwide in other coastal areas expected to be affected by marine ingression due to global climate change

u series evidence for two high last interglacial sea levels in southeastern tunisia abstract pleistocene raised marine deposits in southeastern tunisia consist of a siliciclastic unit that culminates at 3 m asl overlain by a carbonate rich unit with strombus bubonius that culminates at 5 m asl 234 u 238 u ratios on fossil ostraea shells from both units are compatible with a marine origin from the uranium incorporated into the shells and show narrowly clustered 230 th ages respectively between 147 and 110 ka and 141 and 100 ka the two units were therefore developed during marine isotopic substage 5e miss 5e last interglacial their heights are comparable to those of contemporaneous marine deposits found in many tectonically stable areas of the world such as in the bahamas and in bermuda and can therefore be used as indicators of eustatic changes during the last interglacial it is argued that on the basis of this evidence the last interglacial was characterised by two eustatic maxima

late quaternary beach deposits and archaeological relicts on the coasts of cyprus and the possible implications of sea level changes and tectonics on the early populations

sea level change during the holocene in sardinia and in the northeastern adriatic central mediterranean sea from archaeological and geomorphological data abstract we provide new data on relative sea level change from the late holocene for two locations in the central mediterranean sardinia and ne adriatico they are based on precise measures of submerged archaeological and tide notch markers that are good indicators of past sea level elevation twelve submerged archaeological sites were studied six aged between 2 5 and 1 6 ka bp located along the sardinia coast and a further six dated 2 0 ka bp located along the ne adriatic coast italy slovenia and croatia for sardinia we also use beach rock and core data that can be related to holocene sea level the elevations of selected significant archaeological markers were measured with respect to the present sea level applying corrections for tide and atmospheric pressure values at the time of surveys the interpretation of the functional heights related to sea level at the time of their construction provides data on the relative changes between land and sea these data are compared with predictions derived from a new glacio hydro isostatic model associated with the last glacial cycle sardinia is tectonically relatively stable and we use the sea level data from this island to calibrate our models for eustatic and glacio hydro isostatic change the results are consistent with those from another tectonically stable site the versilia plain of italy the northeast adriatic italy slovenia and croatia is an area of subsidence and we use the calibrated model results to separate out the isostatic from the tectonic contributions this indicates that the adriatic coast from the gulf of trieste to the southern end of istria has tectonically subsided by 1 5 m since roman times

two dimensional ionospheric flow pattern associated with auroral streamers 1 we present direct two dimensional flow observations and auroral images from the super dual auroral radar network superdarn radar and wideband imaging camera onboard imager for magnetopause to aurora global exploration image wic imager to investigate the ionospheric flow pattern associated with auroral streamers for four events using the superdarn observations allows us to observe the flow associated with the streamers in the context of the larger scale background convection for all four cases studied streamers developed from preexisting east west ew arcs that initiated from bead like or small scale auroral intensifications around the auroral poleward boundary we find a vortex like flow pattern with clockwise sense surrounding both the initial auroral forms and the ensuing streamers we also found in three cases signatures of flow bifurcations at the equatorward end of the streamers which suggests a double vortex like flow pattern with the counterclockwise vortex east of the clockwise one our results are consistent with the double vortex flow structure that results from interchange convection associated with a plasma sheet bubble predicted by different numerical simulations this supports several previous studies and offers more complete observational evidence that the observed flow pattern may be the ionospheric manifestation of interchange instability in the plasma sheet

evidence of active subsidence at basiluzzo island aeolian islands southern italy inferred from a roman age wharf abstract the aeolian arc southern tyrrhenian sea italy is one of the most active volcanic areas of the mediterranean basin affected by volcanic hydrothermal and seismic activity ancient populations settled this region since historical times building coastal installations which currently are valuable archaeological indicators of relative sea level changes and vertical land movements in this study we show and discuss data on the relative sea level change estimated from a submerged wharf of roman age dated between 50 b c and 50 a d located at basiluzzo island this structure has been studied through marine surveys and archaeological interpretations and is presently located at a corrected depth of 4 10 0 2 m we explain this submergence by a cumulative effect of the relative sea level change caused by the regional glacio hydro isostatic signal active since the end of the last glacial maximum and the local volcano tectonic land subsidence finally a total subsidence rate of 2 05 0 1 mm yr 1 with a volcano tectonic contribution of 1 43 0 1 mm yr 1 for the last 2 ka bp is inferred from the comparison against the latest predicted sea level curve for the southern tyrrhenian sea suggesting new evaluations of the volcano tectonic hazard for this area of the aeolian islands

bounds on the time history and holocene mass budget of antarctica from sea level records in se tunisia solving the sea level equation for a maxwell earth we analyze the sensitivity of holocene sea level records in se tunisia to the time history of remote ice sheets assuming that mantle viscosity increases moderately with depth we find that in this region the sea level variations driven by the northern hemisphere ice sheets cancel so that the late holocene sea level high stand suggested by the geological record merely reflects the melting history of antarctica new insight into the history of this ice sheet is obtained analyzing the information contained in a revised set of relative sea level observations for sites across the mediterranean covering the last 8 kyrs from a trial and error misfit analysis it holds true that in this region the match between model predictions and observations improves when the volume of water released from antarctica is well below the value imposed by the ice3g chronology and when a sudden meltwater pulse is allowed between 8 and 7 kyrs before present corresponding to the epoch of the catastrophic rise event known as cre3

accounting for magnetic diffusion in core flow inversions from geomagnetic secular variation summary we use numerical dynamos to investigate the possible role of magnetic diffusion at the top of the core we find that the contribution of radial magnetic diffusion to the secular variation is correlated with that of tangential magnetic diffusion for a wide range of control parameters the correlation between the two diffusive terms is interpreted in terms of the variation in the strength of poloidal flow along a columnar flow tube the amplitude ratio of the two diffusive terms is used to estimate the probable contribution of radial magnetic diffusion to the secular variation at earth like conditions we then apply a model where radial magnetic diffusion is proportional to tangential diffusion to core flow inversions of geomagnetic secular variation data we find that including magnetic diffusion does not change dramatically the global flow but some significant local variations appear in the non frozen flux core flow models termed diffusive the hemispherical dichotomy between the active atlantic and quiet pacific is weaker a cyclonic vortex below north america emerges and the vortex below asia is stronger our results have several important geophysical implications first our diffusive flow models contain some flow activity at low latitudes in the pacific suggesting a local balance between magnetic field advection and diffusion in that region second the cyclone below north america in our diffusive flows reconciles the difference between mantle driven thermal wind predictions and frozen flux core flow models and is consistent with the prominent intense magnetic flux patch below north america in geomagnetic field models finally we hypothesize that magnetic diffusion near the core surface plays a larger role in the geomagnetic secular variation than usually assumed

late holocene tsunamogenic coseismic uplift in kerkira island greece the presence of a coralligenic like bioherm constituted by boulders up to 1 2 m in diameter cemented by bioconcretions of calcareous algae and vermetids spp has been recognized in the southernmost part of kerkira island this biostructure is placed at up to 1 4 m above the present mean sea level a few hundred meters north well developed beach rocks are at about the same elevation the morphological continuity of these landforms allows us to hypothesize that a recent coseismic uplift interested this area ams age determination has been performed on different vermetids sampled in the upper part of the raised bioherm moreover a complete review of the chronological data cited in the bibliography highlights the difficulties in the use of some bioindicators as chronologically precise sea level indicators the entire data set suggests a late holocene tectonic behaviour characterized by sequences of subsidence and coseismic uplift in particular the age of the raised bioherm suggests that a coseismic uplift occurred 3 ka bp due to an earthquake of regional interest capable of generating a strong tsunami that impacted the nearest coast of lefkada island and the plaghia peninsula

late pleistocene and holocene sea level change in greece and south western turkey a separation of eustatic isostatic and tectonic contributions summary sea level change during late pleistocene and holocene times is a combination of eustatic isostatic and tectonic contributions in the central mediterranean sea region of greece and western turkey the isostatic components are important due to the changing gravitational potential of the earth the readjustment of the crust upon the removal of the large ice sheets and the addition of the meltwater into the oceans including the mediterranean changes in relative sea level due to these glacio hydro isostatic adjustments have reached amplitudes of 1 mm yr 1 during the last few thousand years a model for the isostatic contribution to sea level change including the movement of shorelines due to the combined eustatic isostatic changes is developed based on earth model and ice sheet parameters estimated from sea level observations from other areas comparisons of this model with observations of sea level change permit rates of vertical movement to be estimated for late holocene time allowance for the isostatic factors makes a significant difference to these rates the plains of argolis lakonia messinia and navarine in the southern peloponnese for example appear to be tectonically stable on time scales of a few thousand years and longer consistent with the position of the last interglacial shoreline close to the present day sea level the observations here of a rising sea level are largely the consequence of the glacio hydro isostasy and not of a long term tectonic process crete as a whole is subject to tectonic uplift but at variable rates and forms part of an arcuate zone of uplift extending from rhodes and karpathos in the east to kithera in the west at rates that locally exceed 4 mm yr 1 the southern shore of the gulf of corinthos is also subject to uplift at rates approaching 1 5 mm yr 1 these isostatically corrected estimates for the past few thousand years are in agreement with longer term estimates based on the position of the last interglacial shoreline only on the perachora peninsula do the tectonic rates over these two time intervals appear to be in disagreement with the late holocene rates being much higher than the long term rates

large scale current systems and ground magnetic disturbance during deep substorm injections 1 we present a detailed analysis of the large scale current systems and their effects on the ground magnetic field disturbance for an idealized substorm event simulated with the equilibrium version of the rice convection model the objective of this study is to evaluate how well the bubble injection picture can account for some classic features of the substorm expansion phase the entropy depletion inside the bubble is intentionally designed to be so severe that it can penetrate deep into geosynchronous orbit the results are summarized as follows 1 both the region 1 sense and region 2 sense field aligned currents facs intensify substantially the former resembles the substorm current wedge and flows along the eastern and western edges of the bubble the latter is connected to the enhanced partial ring current in the magnetosphere associated with a dipolarization front earthward of the bubble in the ionosphere these two pairs of facs are mostly interconnected via pedersen currents 2 the horizontal ionospheric currents show a significant westward electrojet peaked at the equatorward edge of the footprint of the bubble the estimated ground magnetic disturbance is consistent with the typical features at various locations relative to the center of the westward electrojet 3 a prominent harang reversal like boundary is seen in both ground h disturbance and plasma flow pattern appearing in the westward portion of the equatorward edge of the bubble footprint with a latitudinal extent of 5 and a longitudinal extent of the half width of the bubble 4 the dramatic dipolarization inside the bubble causes the ionospheric map of the inner plasma sheet to exhibit a bulge like structure which may be related to auroral poleward expansion 5 the remarkable appearance of the westward electrojet harang reversal like boundary and poleward expansion starts when the bubble reaches the magnetic transition region from tail like to dipole like configuration we also estimate the horizontal and vertical currents using magnetograms at tens of ground stations for a deep injection substorm event occurred on april 9 2008 resulting in a picture that is qualitatively consistent with the simulation based on the simulations and the observations an overall picture of the ionospheric dynamics and its magnetospheric drivers during deep bubble injections is obtained

rcm e simulation of a thin arc preceded by a north south aligned auroral streamer the time history of events and macroscale interactions during substorms themis all sky imager data have recently revealed a repeatable sequence that occurs during many auroral substorms in which a newly formed thin arc is preceded by an equatorward propagating streamer the paper aims at modeling this sequence using the rice convection model equilibrium the simulation shows a thin arc arising when a plasma sheet bubble with its pv5 3 reduced to the transition region value arrives at the magnetic transition region the modeled thin arc consists of two parts the one east of the streamer is the result of the bubble pushing high pv5 3 flux tubes ahead of it strengthening the upward region 2 current and the one west of the streamer is associated with westward drifting bubble particles sliding along the transition region the model predicts that 1 the westward and eastward leading edges of the thin arc propagate azimuthally at a speed of 0 5 2 7 km s and 2 the streamer induced thin arc is accompanied by classic signatures of bubble injections

mid holocene emergence of southern tunisian coasts abstract we present new sea level data from the coasts of southern tunisia between the gulf of gabes and the libyan border the work tests previously published evidence on holocene shorelines and confirmed that a distinct emergence has occurred in this area during this time the emergence peak lies at least 186 11 cm above present and is inferred from 1 ams radiocarbon dates of subtidal vermetids and boring shells collected in growth position and 2 careful assessment of tidal heights maximum emergence took place between about 6000 and 5000 14c years bp it cannot be ascribed to tectonics and is probably related to post glacial hydro isostatic effects it challenges the inference of a 3 m global sea level rise since 6000 years bp due to residual antarctic melting

millstone quarries along the mediterranean coast chronology morphological variability and relationships with past sea levels abstract the coast of the mediterranean provide several remnants of ancient coastal quarries which are now useful to study sea level change occurring during the last millennia millstones quarries were exploited with same quarrying techniques from rocks like beachrocks sandstones or similar lithologies were shaped to be suitable to grind olives seeds and wheat to produce oil and flour or to break apart soft rocks in this study we integrated historical sources aerial photography field surveys and palaeo sea level modelling to investigate a number of millstones quarries with the aim to asses the intervening sea level change that occurred since the quarries were abandoned we investigated on their chronology spatial distribution and spatial relationship to the sea level our results indicate that most of these were carved close to sea level between 1 45 ka and 0 25 ka cal bp but mainly around 0 45 cal ka bp despite the uncertainties associated with the chronology in we found good agreement between their lowest elevation between 0 33 m and 0 06 m and the paleo sea levels as predicted by the gia models

archaeological and geomorphological indicators of the historical sea level changes and the related palaeogeographical reconstruction of the ancient foreharbour of lechaion east corinth gulf greece abstract study of the architectural morphological and constructional features of the coastal harbour installations of the ancient foreharbour of lechaion indicates that they were built or rebuilt during the period of the roman domination of corinth and has facilitated the reconstruction of the vertical movements and the palaeogeography of the coast on the basis of the current position of the sea level indicators including beachrocks fossilized uplifted and submerged marine notches and ancient coastal harbour installations and the relationship between them the sea level during the roman operation of the harbour was determined to be 0 90 m lower than at present furthermore the subsequent abandonment of the harbour and the siltation of its constructions were determined during two successive tectonic subsidence co seismic events the sea level rose by 2 0 m in total 1 60 m during the first event and 0 40 m during the second one a strong uplift tectonic event followed and the sea level dropped by 1 10 m this regression of the sea was responsible for the present shoreline morphology determination of the sea level fluctuation at the shore of the ancient harbour of lechaion allowed the palaeogeographical reconstruction of the coast in different stages related to these changes

unsolved problems mesoscale polar cap flow channels structure propagation and effects on space weather disturbances recent evidence indicates that the magnetosphere ionosphere system is frequently driven by dynamic mesoscale flow structures that are first seen near the dayside cusps move across the open field line regions of the polar caps and then enter the plasma sheet where they lead to a large variety of space weather disturbances it will be important to uncover the features of these flow enhancements including their structure how they propagate across the polar cap and what controls their dynamic effects after reaching the nightside plasma sheet

palaeogeographical and palaeoenvironmental reconstruction of the medjerda delta tunisia during the holocene abstract the progradation of the medjerda delta has been the subject of many studies since the 19th century the scale and the rapidity of this phenomenon interested researchers in various fields early on such as geomorphology geology palaeogeography history archaeology or geoarchaeology indeed the delta prograded by around 10 km over 3 millennia at the time of its foundation supposedly at the end of the 12th century bc the phoenician city of utica was located on a promontory bathed by the sea but the sediments carried by the medjerda progressively sealed the bay leaving the tip of the utica promontory now 10 km inland this area is therefore an exception to the general pattern along the tunisian coast since as over the same period everywhere else there is a regression of the coastline owing to a sea level rise of several decimeters based on multi proxy analyses of two coring transects this paper aims to reconstruct the palaeoenvironments and the palaeogeography of the medjerda delta s progradation since the mid holocene some aspects of which are described in ancient sources the results highlight in particular an episode of high intensity flooding around the 4th century ad which is consistent with episodes of high floods and an increase in sedimentation rates recorded in the watershed at the end of the roman period the gradual abandonment of the city of utica can certainly be related to the activity of the medjerda river but our results show that it is because of an increase of fluvial sediment contribution in connection with an erosive crisis in the headwaters and not because of the change of course of the river which had occurred long before

large scale imaging of high latitude convection with super dual auroral radar network hf radar observations the hf radars of the super dual auroral radar network superdarn provide measurements of the e b drift of ionospheric plasma over extended regions of the high latitude ionosphere with the recent augmentation of the northern hemisphere component to six radars a sizable fraction of the entire convection zone approximately one third can be imaged nearly instantaneously 2 min to date the two dimensional convection velocity has been mapped by combining line of sight velocity measurements obtained from pairs of radars within common volume areas we describe a new method of deriving large scale convection maps based on all the available velocity data the measurements are used to determine a solution for the distribution of electrostatic potential expressed as a series expansion in spherical harmonics the addition of data from a statistical model constrains the solution in regions of no data coverage for low order expansions the results provide a gross characterization of the global convection we discuss the processing of the radar velocity data the factors that condition the fitting and the reliability of the results we present examples of imaging that demonstrate the response of the global convection to variations in the interplanetary magnetic field imf in the case of a sudden polarity change from northward to southward imf the convection is seen to reconfigure globally on very short 6 min timescales

the 17 march 2013 storm synergy of observations related to electric field modes and their ionospheric and magnetospheric effects the main phase of the 2013 march 17 storm had excellent coverage from ground based instruments and from low and high altitude spacecraft allowing for evaluation of the relations between major storm time phenomena that are often considered separately the shock impact with its concurrent southward imf immediately drove dramatic poleward expansion of the poleward boundary of the auroral oval implying strong nightside reconnection strong auroral activity and strong penetrating mid latitude convection and ionospheric currents this was followed by periods of southward imf driving of electric fields that were at first relatively smooth as often employed in storm modeling but then became extremely bursty and structured associated with equatorward extending auroral streamers the auroral oval did not expand much further poleward during these two latter periods suggesting a lower overall nightside reconnection rate than that during the first period and approximate balance with dayside reconnection characteristics of these three modes of driving were reflected in horizontal and field aligned currents equatorward expansion of the auroral oval occurred predominantly during the structured convection mode when electric fields became extremely bursty the period of this third mode also approximately corresponded to the time of largest equatorward motion of the ionospheric trough of apparent transport of high tec features into the auroral oval from the polar cap and of largest earthward injection of ions and electrons into the ring current the enhanced responses of the aurora currents tec and the ring current indicate a common driving of all these stormtime features during the bursty convection mode period

genesis and evolution of a beach ridge plain reflecting relative sea level rise a case study from trab el makhadha gulf of gabes southeastern tunisia abstract the trab el makhadha beach ridge plain presents a progradational shoreline feature on the gulf of gabes tunisia diachronic analysis coupled with a morpho sedimentary approach was applied to elucidate the genesis mode of the beach ridge plain its sedimentary sources and the climatic conditions responsible for the prograding trends in the gulf of gabes shapes dimensions sedimentologic compositions and other textural parameters of the sandy ridges have been analyzed therein we found that the trab el makhdha coast is made up of two distinctive categories of eolian beach ridge complex progradational sequences implying a significant change in climatic and hydrological conditions during the deposition of each ridge in the holocene sequence about 5600 14c years old the predominance of detrital material suggests an important contribution to sediment supply from continental input the preservation of the eolian beach ridge and its adjacent marine sediment has been favored by the postglacial hydro isostatic rebound today the paucity of rainfall is reflected by the decrease in input of terrigenous material therefore the modern sequence which has been emerging since 1987 is made mainly of bioclastic sand supplied by subaqueous shoals due to a rapid rise in sea level the observed decrease of sea level around 2100 14c yr b p largely contributed to the formation of the swale the formation of the beach ridge plain shows that since the middle holocene highstand the coastal segment of trab el makhadha has been governed by equilibrium of sediment abundance

structures and tectonics of tunisia abstract in the tunisian atlas nothing is known about the nature of the acoustic basement and in the saharan cratonic part only a few deep exploration wells have reached the precambrian below a thick unfolded palaeozoic sequence north of the craton a major set of faults w e or wnw ese represents the southern limit of palaeo tethys thick sequences of marine late carboniferous and permian were developed below the jeffara and chott jerid triassic evaporites are thick below the tunisian atlas which has enabled detachment of the cover from the basement and folding into plis de couverture structures large diapiric intrusions are known especially in the northwestern sillon tunisien tunisian trough from east to west there is a progressive variation from the stable platform on the eastern side to the unstable shelf of western tunisia between these a zone of tectonic instability named the north south axis corresponds to a deep fault system that acted as a positive suture characterized by tilted blocks gaps in sedimentation and reduced or condensed sequences in the north the unstable shelf of western tunisia grades to the deep furrows where the sediments now forming the tellian and numidian nappes were deposited these nappes overthrust the autochthonous foreland during the miocene orogeny the main folding took place in the pliocene and early pleistocene recent tectonic activity occurs along the main fault zones

evidence of vertical tectonic uplift at briatico calabria italy inferred from roman age maritime archaeological indicators abstract calabria is one of the most complex geological regions of the mediterranean basin which experienced large earthquakes and uplift and is still undergoing active tectonics along its coasts are located archaeological sites that can be used as powerful indicators of the relative vertical movements between land and sea since their construction this paper presents and discusses data on the relative sea level change as estimated from maritime archaeological indicators of the last 2 0 ka bp existing along the tyrrhenian coast of briatico these sites still show the remnants of a roman age fish tank and a submerged breakwater about 320 m long the palaeo sea level has been obtained measuring the functional elevation of the significant archaeological markers their elevation was compared against the latest predicted sea level curve for the holocene along the tyrrhenian coast of calabria as this coastal area is affected by significant and continuous vertical tectonic uplift during pleistocene the data show the counterbalance between coastal uplift and relative sea level change caused by the glacio hydro isostasy acting since the construction of these archaeological sites the sum of these movements determined an about null relative sea level change for this location these data are in contrast with other part of the tectonically stable areas of the mediterranean and provide evidence that crustal uplift continued in the last 1806 50 y at a rate of 0 65 mm y

sea level changes since the middle ages along the coast of the adriatic sea the case of st nicholas basilica bari southern italy abstract during the last decade several papers have been published to estimate the relative sea level change from coastal archaeological indicators of the last 3 4 ka bp in many locations of the italian coasts and the mediterranean sea the use of the archaeological information has been poorly focused for the middle ages due to the few available coastal installations for this period thus not allowing precise sea level estimation for the last 1000 years to complement the instrumental data available for the last 100 120 years this study discusses an archaeological marker of the middle ages used to reconstruct the story of the sea level changes in the last 1000 years at the st nicholas basilica built in 1087 ad along the coast of bari apulia southern italy the elevations of the ancient floor levels of the crypt underwent repeated flooding due to a continuous rising of the groundwater table which required restoration and uplifting of pavements between 1087 and 1956 to keep them dry the palaeo sea levels have been obtained by measuring the position of the groundwater table the elevation of which is mainly driven by sea level since the time of the construction of the basilica the elevation of the archaeological markers and the water table were compared against the latest predicted sea level curve for the holocene along the coast of bari as this coastal area is unaffected by significant vertical tectonic motion over the last 125 ky the data detail the timing of the relative sea level rise since the middle ages and can be used to improve the predicted sea level curve for this region for the last 1000 years

assessing tectonic subsidence from estimates of holocene relative sea level change an example from the nw mediterranean magra plain italy new sedimentological sea level indicators are presented from the river magra coastal plain in nw italy chronologically well constrained paralic peats and organic sediments which had been deposited in a defined relationship with sea level were recovered in four of the seven boreholes considered in this work their evolution scatters in the time span of the past 6000 years since the cores are located within a single sedimentary basin it was possible to correct the elevation of marker horizons for the effect of sediment compaction by means of both a field and a geotechnical method thus seven reliable index points for the mid to late holocene sea level rise were obtained the age depth model derived from them was compared with that of sea level predictions from two different glacial isostatic adjustment gia models available for the area in both cases the modelled sea level estimates overlie the index points suggesting lower relative sea level elevation than the one predicted considering the combin

vertical land movements and sea level changes along the coast of crete greece since late holocene abstract geomorphological survey along the coasts of crete revealed widespread evidence of uplifted and submerged tidal notches different phases of beachrock formation and many relics of ancient coastal constructions about 1 6 ka bp when the sea level was at 1 25 0 05 m the western tectonic block of the island uplifted by 9 15 0 20 m in its westernmost extremity and by 2 00 m approximately in its eastern boundary and tilted southeastward repeated preceding episodes of subsidence submerged the western part of the island by 1 60 m in a period of 2300 years along the western coast the younger phase of the submerged beachrocks was identified and measured at nineteen locations together with the submerged tidal notches and archaeological remains land subsidence by 1 25 0 05 m subsequent to the uplift of the western part occurred after the late venetian occupation period ad 1600 coincident with the submersion of the eastern part of the island in central and eastern crete the relative sea level change evidence from tidal notches and beachrocks revealed five distinct sea level stands at 6 55 0 55 m 3 95 0 35 m 2 70 0 15 m 1 25 0 05 m and 0 55 0 05 m the lowest sea level stand can be identified with the oldest dated tidal notch of western crete between 4200 90 b p and 3930 90 b p two subsequent sea levels can be linked with the protopalatial 1900 1700 b c or 1600 b c and neopalatial period 1600 1450 b c of the minoan civilization according to submerged prehistoric morphologies and inundated minoan constructions the change of sea level from 2 70 0 15 m to 1 25 0 05 m is placed between 1450 b c and the fourth century bc the dating of 1 25 0 05 m sea level stand was based on the measurement and interpretation of ancient coastal installations built along the coast of central and eastern crete during classical hellenistic roman byzantine and venetian periods historical sources report a relative sea level rise by 0 70 m during the ad 1604 paroxysmal event over the last 400 years the relative sea level rose by 0 55 m the uplift of the coast of western crete and the submersion in its central and eastern coast indicate that during the ad 365 paroxysmal event the island was split along a tectonic boundary identified with the neotectonic graben of spili and its northern and southern prolongation

simulations of a quasi taylor state geomagnetic field including polarity reversals on the earth simulator high resolution low viscosity geodynamo simulations have been carried out on the earth simulator one of the fastest supercomputers in a dynamic regime similar to that of earth s core that is in a quasi taylor state our dynamo models exhibit features of the geodynamo not only in spatial and temporal characteristics but also in dynamics polarity reversals occurred when magnetic flux patches at high latitudes moved poleward and disappeared patches with reversed field at low and mid latitudes then moved poleward

ionospheric signatures of a plasma sheet rebound flow during a substorm onset 1 magnetic reconnection in earth s magnetotail produces fast earthward flows in the plasma sheet tailward flows are often observed associated with the earthward flows both return flow vortices at the flanks of an earthward flow channel and rebound of the earthward flow from the intense dipolar magnetic field of the inner magnetosphere have been shown to explain tailward flows observed near earth we combine plasma sheet measurements from cluster with conjugate ground based magnetic and auroral data to examine the development of earthward and tailward flow signatures during a substorm onset we show for the first time observations of ionospheric signatures that appear to be associated with rebound flows because of the highly dynamic magnetotail configuration special care is taken with the satellite footprint mapping the ionospheric footprints produced by the event oriented am02 model drift equatorward and poleward in response to tail magnetic field stretching and dipolarization respectively the footprint motion matches that of the ambient ionospheric structures and the plasma flow measured by cluster agrees with that inferred from the conjugate ionospheric observations confirming the validity of the am02 mapping the ionospheric signatures of fast earthward flows during a substorm onset are shown to resemble the known signatures of quiet time flows including equatorward propagating auroral streamers inside a channel of enhanced poleward equivalent current however the large scale dipolarization results in additional poleward expansion of the signatures as has been predicted by simulations