glacial stage ice core records from the subtropical dunde ice cap china the first ice core record of both the holocene and wisconsin wiirm late glacial stage lgs from the subtropics has been extracted from three ice cores to bedrock from the dunde ice cap on the north central qinghai tibetan plateau ice thicknesses at the ice cap summit average 138 m the bedrock surface is relatively flat surface and basal temperatures are 7 3 and 4 7 c respectively and the ice cap exhibits radial flow away from the summit dome these records reveal a major change in the climate of the plateau 10 000 years ago and suggest that lgs conditions were colder wetter and dustier than holocene conditions this is inferred from the more negative 6180 ratios increased dust content decreased soluble aerosol concentrations and reduced ice crystal sizes which characterize the lgs part of the cores total b radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been 400 mm a 1 at the summit the ice cores have been dated using a combination of annual layers in the insoluble dust and 6180 in the upper sections of core visible dust layers which are annual and ice flow modeling the oxygen isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record

thermal expansion contraction and slope instability of a fumarole field inferred from geodetic measurements at vulcano between 1987 and 1993 fumarole temperatures at the fossa crater of vulcano italy were characterized by the highest values since the 1920 s increasing from about 300 c in 1987 to 690 c in may 1993 before decreasing to 400 c by 1996 1997 during 1990 vulcano s electronic distance measurement edm network was expanded to provide more detailed coverage of the northern sector of the fossa crater and in particular to monitor the movement of the northern flank the fossa cone measurements carried out between 1990 and 1994 showed shortening by about 6 to 7 cm along baselines measured to a small section of the northern rim over the following four years these baselines showed a slow extension by about 3 cm to gradually recover part of the previous deformation we believe that the shortening and lengthening of the edm baselines was respectively due to the increasing and decreasing temperature of the rock body lying close to the deforming area this caused thermal expansion followed by contraction the positive movement of the rim was not completely matched by a negative recovery suggesting that a non recoverable sliding movement was also responsible for some of the shortening of the baselines we verified our hypothesis by calculating the expected dilatation of a rock body as a function of the volume of rock heated and its thermal expansion coefficient and compared the expected deformation to that observed the geodetic investigation showed that the unstable portion affects a small length of the rim about 100 m long and involves a volume of about 0 8 106 m3 however this zone lies directly above a particularly unstable portion of the flank as well as the main village and port on the island

hydrothermal fluid flow disruptions evidenced by subsurface changes in heat transfer modality the la fossa cone of vulcano italy case study detecting volcanic unrest is of primary importance for eruption forecasting especially on volcanoes characterized by highly dangerous and often seemingly unpredictable phreatic or phreatomagmatic eruptions we present a simple and innovative analysis of shallow vertical temperature profiles to depths of 70 cm these data were recorded at la fossa cone of vulcano aeolian islands italy during an episode of increased hydrothermal and seismic activities that occurred between september and december 2009 this work involves the use of the coefficient of determination r 2 on vertical temperature profiles in order to identify changes in conductive versus convec tive heat transfer modality the increase in convective heat transfer can be related to the disruption of the hydrothermal system due to its pressurization and or variation of ground permeability between the hydrothermal system and the surface while raw temperature data do not evidence any significant variation during the period investigated and the classic temperature gradient is highly influenced by seasonal variations the fluctuation of r 2 displayed striking spikes that coincided with the seismic swarm inside the volcanic edifice such a low cost device associated with easy real time data processing could constitute a very promising yet deceptively simple technique to monitor hydrothermal systems in order to assess the hazard posed by high energy eruptions for populations living close to active volcanoes

thermal characterization of the vulcano fumarole field ground based thermal infrared surveys can contribute to complete heat budget inventories for fumarole fields however variations in atmospheric conditions plume condensation and mixed pixel effects can complicate vent area and temperature measurements analysis of vent temperature frequency distributions can be used however to characterise and quantify thermal regions within a field we examine this using four thermal infrared thermometer and thermal image surveys of the vulcano fossa fumarole field italy during june 2004 and july 2005 these surveys show that regions occupied by low temperature vents are characterised by distributions that are tightly clustered around the mean i e the standard deviation is low highly peaked positive kurtosis and skewed in the low temperature direction negative skewness this population is associated with wet fumaroles where boiling controls maximum temperature to cause a narrow distribution with a mode at 90 100 c in contrast high temperature vent regions have distributions that are widely spread about the mean i e the standard deviation is high relatively flat negative kurtosis and skewed in the high temperature direction positive skewness in this dry case fumaroles are water free so that maximum temperatures are not fixed by boiling as a result greater temperature variation is possible we use these results to define two vent types at vulcano on the basis of their thermal characteristics 1 concentrated localized regions of high temperature vents and 2 dispersed low temperature vents these occur within a much larger region of diffuse heat emission across which surfaces are heated by steam condensation the heat from which causes elevated surface temperatures for vulcano s lower fumarole zone high and low temperature vents occupied total areas of 3 and 6 m2 respectively and occurred within a larger 430 m2 vent free zone of diffuse heat emission for this lower zone we estimate that 21 43 103 w of heat was lost by diffuse heat emission a further 4 5 103 w was lost by radiation from high temperature vents and 6 5 103 w from low temperature vents thus radiative heat losses from high and low temperature vents within vulcano s lower fumarole zone respectively account for 10 and 15 of the total heat lost from this zone this shows that radiation from open vents can account for a non trivial portion of the total fumarole field heat budget

tornillos at vulcano clues to the dynamics of the hydrothermal system abstract the number of tornillo events has recently increased at the vulcano island italy while only 15 tornillos were recorded during 2004 2006 584 events occurred in 2007 2008 they were located just below la fossa crater at depths ranging between 0 1 and 1 km b s l during two intervals in 2007 2008 increases in the number of tornillos took place at the same time as temperature and geochemical anomalies were observed the spectral content of the tornillos generally characterized by one two dominant spectral peaks near 6 and 10 hz varied over time with changes also noted in the quality factors the simplest source mechanism proposed for tornillos is the free eigenvibration of a fluid volume within a crack or a conduit based on this model we propose a causal relationship between the temperature and geochemical anomalies and the increases in numbers of tornillos as the amount of hydrothermal fluids increases during the anomalies the upward flux of fluids grows the consequent changes in the pressure temperature and dynamics of the system of cracks and conduits result in the generation of tornillos based on the fluid filled crack conduit model the shallow depths of the sources and the values of the quality factors the fluid within the resonant crack conduit was inferred to be an ash gas or water droplet gas mixture moreover the observed variations in the wavefield can be caused by small changes in the location of the source in the source mechanism or in the medium in between the source and the seismic station finally another peculiar feature of tornillos is the amplitude modulation that can be explained as a result of a beating phenomenon

correlated increase in co2 fumarolic content and diffuse emission from la fossa crater vulcano italy evidence of volcanic unrest or increasing gas release from a stationary deep magma body 1 the peculiarity of the quiescent la fossa volcano is the occurrence of crises characterized by strong increases of fumarole t and output and by chemical changes indicative of an increasing input of magmatic fluids several surveys carried out during a new crisis began in november 2004 indicate that the total diffuse co2 emission for the crater area increases by one order of magnitude during crises up to 1600 ton d 1 in december 2005 concern exists on the possibility that these crises be related to an unrest process leading to eruption the repetition along decades of the same gas compositional variations during crises their temporal coincidence with increases of the local shallow seismicity and the lack of any significant ground motion rather suggest that they correspond to moments of increasing volatile release from a stationary magma system

structure of an active volcano associated with a resurgent block inferred from thermal mapping the yasur yenkahe volcanic complex vanuatu subsurface thermal measurements provide a valuable tool to map hydrothermal fluid release zones in active volcanic areas on the yasur yenkahe volcanic complex tanna island vanuatu archipelago fumaroles and hot springs abound signs of upraising heat fluxes associated to a well developed hydrothermal activity combination of high resolution mapping of ground thermal anomalies with geomorphological analysis allows the characterization of the structural relationships between the active yasur volcano and the yenkahe resurgent block a complex system of heat release and hydrothermal fluid circulation below the yasur yenkahe complex is evidenced circulation though propagating vertically as a whole is funneled by stratification thus the main thermal fluid released is almost exclusively concentrated along structural limits that break the seals induced by the stratified nature of the ground three types of medium high temperature anomalies have been evidenced 1 broad hydrothermalized areas linked with planar stratification that favor lateral spreading 2 linear segments that represent active faults and 3 arcuate segments related to paleo crater rims the limit between the yasur volcano and the yenkahe resurgent block is characterized by an active fault system accommodating both the rapid uplift of the yenkahe block and the overloading induced by the volcano weight in such a setting faults converge below the cone of yasur which acts as a focus for the faults evidence of such structures sometimes hidden in the landscape but detected by thermal measurements is critical for risk assessment of flank landslides

tropical glaciers potential for ice core paleoclimatic reconstructions the objective of this work is to evaluate the potential of tropical glaciers and ice caps for the reconstruction of past climatic conditions by the analysis of firn and ice cores samples were collected in pits and from cores retrieved on three snow fields in the south american andes quelccaya ice cap and huascaran in peru and chimborazo in ecuador these are compared with results from west africa and indonesia measurements include the microparticle concentration oxygen isotopic abundance ratios and total beta radioactivity which in polar regions often exhibit seasonal depositional cycles annual variations in these three parameters are fairly well defined on quelccaya and huascaran and are apparently absent on chimborazo the quelccaya ice cap contains the best preserved annual signal for all three parameters and although in some instances the annual cycle is difficult to distinguish the measurement of more than one stratigraphic parameter aids in the interpretation of the firn core records the relatively flat bottom topography under quelccaya suggests a simple ice flow regime and depth age calculations indicate that an ice core to bedrock should contain a record of 600 to 1300 years this inference was confirmed by drilling to bedrock in 1983 this investigation of tropical glaciers indicates that the quelccaya ice cap on the eastern edge of the peruvian andes has excellent potential to contain a lengthy and interpretable record of climatic conditions within the tropics of south america

acid resistant microfossils used in the determination of palaeozoic palaeoenvironments in libya abstract a study of silurian acid resistant microfossils from the ghadames basin in tripolitania libya using palynological techniques revealed that the following may be used as palaeoenvironmental indicators spores acritarchs chitinozoa tasmanitids scolecodonts plant tissue eurypterid cuticle and graptolite siculae the palynofacies were defined by quantitative and qualitative diversification of these assemblages sedimentological features were used to confirm these proposed facies six distinct types of palynofacies were identified and related to models of distance from the shoreline it is tentatively suggested that they may relate to lagoonal intermediate and open marine environments

devonian sea level change in bolivia a high palaeolatitude biostratigraphical calibration of the global sea level curve article i nfo available online xxxx during the devonian period the cool water malvinokaffric realm was located at high palaeolatitudes in the southern hemisphere the realm is defined by its highly endemic marine benthic fauna which makes extra malvinokaffric correlations problematic investigation of the devonian palynomorphs from an extensive regional sub surface dataset 24 wells in the chaco basin bolivia reveals the presence of a number of stratigraphically restricted and regionally correlative epiboles peak abundances of the distinctive palynomorphs bimerga bensonii crucidia camirense evittia sommeri petrovina connata and ramochitina magnifica these palynomorph epiboles were then located at outcrop by a high resolution palynological investigation 225 samples of two bolivian outcrop localities in the chaco basin bermejo santa cruz department and campo redondo chiquisaca department the important evittia sommeri epibole in the basal los monos formation is related to a marine transgression that is present in both these outcrop sections additional chronostratigraphic control on this marine transgression comes from the occurrence of rare goniatites in the base of the huamampampa formation at campo redondo which are at least early eifelian in age post chot c event based on the goniatite together with spore data the marine transgression with evittia sommeri in the basal los monos formation can be tentatively assigned to the mid devonian mid late eifelian kacak event the presence of a datable malvinokaffric goniatite has shown that key spore taxa which are used zonally in both laurussia and gondwana do not all have coincident first occurrences in both areas furthermore despite the appearance of some cosmopolitan elements in the microflora mid and late devonian spore assemblages in bolivia are distinct from other regions in being relatively impoverished in both progymnosperm and lycopod spores this floral difference is attributable to the malvinokaffric realm continuing to retain a distinctive cool climatic signature throughout this interval however the sporadic occurrences of extra malvinokaffric macrofauna in restricted stratigraphic intervals of the middle devonian in south america and south africa are significant the oldest known occurrence of the extra malvinokaffric brachiopod tropidoleptus in bolivia is coincident with the late eifelian basal los monos formation transgression hence there was a relationship between influxes of this fauna and marine transgressions i e temporary periods of reduced climatic gradient the migration of devonian spores and particularly heterosporous spores between gondwana and laurussia clearly occurs during the mid and late devonian this is at variance with models claiming a wide rheic ocean during much of the devonian

origin of the fumarolic fluids of vulcano island italy and implications for volcanic surveillance variations in d and 18o values with h2o contents and outlet temperatures indicate that the fumaroles of la fossa crater have discharged mixtures of magmatic water and marine hydrothermal water since 1979 the contribution of meteoric water was low in the period 1979 1982 and very low afterwards the 18o values of the marine hydrothermal component of 5 to 7 2 are due to isotopic exchange with the 18o rich silicates of the rocks under high temperature and low permeability conditions the 18o value of the magmatic end member is generally 3 5 to 4 3 although values as high as 5 5 to 6 5 were reached in the summer of 1988 when magma degassing appears to have extended into the core of the magma body the d values of the end member were close to 20 typical of andesitic waters both the isotopic values and chemical data strongly support a dry model consisting of a central magmatic gas column and a surrounding hydrothermal envelope in which marine hydrothermal brines move along limited fracture zones to undergo total evaporation on approaching the conduits of magmatic fluids the vents at the eastern and western boundaries of the fumarolic field are fed by fluids whose pressure is governed by the coexistence of vapor liquid and halite giving rise to a high risk of phreato magmatic explosions should magma penetrate into these wet environments most la fossa eruptions were triggered by an initial hydrothermal blast and continued with a series of phreatomagmatic explosions the fluids discharged by the forgia vecchia fumaroles are mixed with meteoric water which is largely evaporated although subordinate loss of condensed steam may be responsible for scrubbing most of the acidic gas species the temperatures and pressures and the risk of a sudden pressure increase are low a boiling hydrothermal aquifer at 230 c is present underneath the baia di levante beach this area has a minor risk of hydrothermal explosions

signs of potential renewal of eruptive activity at la fossa vulcano aeolian islands since the end of the last magmatic eruption 1890 activity of la fossa southern tyrrhenian sea italy has consisted of fumarolic emissions of fluctuating intensity fluids are discharged principally at two fumarolic fields located in the northern rim of the active crater and at the beach sited at its northern foot increased thermal seismic and geochemical activity has been recorded since 1978 when an earthquake of m 5 5 occurred in the region this paper combines available geophysical and geochemical information in order to develop a tentative interpretation of two episodes of apparent unrest which occurred in 1985 and 1987 1988 enhancing the risk of renewal of the eruptive activity the 1985 unrest consisted essentially of a sharp build up of the internal pressure in the shallow hydrothermal system which was induced by the injection of hot gases of magmatic origin the crater fumaroles displayed significant increases in co2 and other acid species but their outlet temperature did not change conversely the 1987 1988 episode was characterized by appreciable modifications at the crater fumaroles with only secondary effects at the fumarole system of the beach the sliding of part of the eastern flank of the la fossa cone into the sea occurred on 20 april 1988 when the region was affected by crustal dilatation producing a seismic sequence of relatively high intensity both episodes of unrest were accompanied by increases of local microseismic activity which affected the nothern sector of the island in 1985 and the southern one in 1988 finally a phase of appreciable areal contraction was detected in 1990 probably due to the effect of the cooling and crystallization of magma at relatively shallow depths accompanying the increased thermal activity at the crater fumaroles regional tectonic stress seems to play an important role in the transition of the volcanic system from a phase of relative stability to a phase of apparent unrest inducing the heating and the expansion of shallow hydrothermal fluids available information is insufficient to indicate whether or not the volcano is building towards the renewal of a magmatic eruption and there is no evidence to hypothesize episodes of significant magma migration the frequency of measurements of many parameters needs to be increased in order to learn more about the temporal relationships between geochemical and geophysical variations preceding and accompanying periods of increased thermal activity this will probably be a valid tool for recognizing short term precursors of a future eruption reducing the risk of false alarms

relationships among crustal structure volcanism and strike slip tectonics in the lipari vulcano volcanic complex aeolian islands southern tyrrhenian sea italy abstract the lipari vulcano volcanic complex lvvc aeolian arc southern tyrrhenian sea italy develops along a strike slip fault system that bisects the aeolian arc the lvvc crustal structure is investigated by applying seismic methods to two data sets p wavefronts generated by local and distant events constrain the shallow velocity structure dss data provide shape and depth of the main crustal discontinuities the obtained velocity model shows that the lvvc shallow structure is characterized by the presence of two sharp lateral discontinuities the northern discontinuity bounds a low velocity basin like structure including the la fossa caldera and mt guardia caldera depressions the southern discontinuity coincides with the southern boundary of a high velocity diffractor located beneath the la fossa cone direct modeling of dss data define three crustal discontinuities showing a complex geometry the intra crustal interfaces and the moho discontinuity show an upheaval beneath the lvvc central sector the estimated crustal velocities are lower than those generally reported for the continental crust this feature is due to the high heat flux and fluid circulation affecting the lvvc area the ratio between the thickness of the upper and lower crust and the presence of the moho upheaval are consistent with that reported for continental areas affected by extensional strain the collected geophysical data combined with volcanological and structural information indicate that a the mt guardia and la fossa caldera depressions represent the surface expression of a single structure whose formation is mainly due to tectonic processes b the lvvc crustal structure and the evolution of the volcanism are consistent with those recognized in zones of transition from arc related to rift volcanism in addition results of a preliminary mechanical analysis based on the available structural data indicate low values of the ratio between magmatic overpressure and tectonic stress this suggests a passive mechanism of mantle upwelling the mantle upwelling is due the post collisional normal strike slip tectonics affecting the aeolian arc

interpretation of mono pulse ice radar soundings on two peruvian glaciers during the 1979 and 1980 field seasons mono pulse radar sounding experiments were carried out on the quelccaya ice cap in southern peru and the col of huascaran in northern peru along with ice thickness determinations some of which are described in detail elsewhere the maximum ice thickness measured using the radar was 165 20 m for the quelccaya ice cap and 190 10 m for huascaran studies were conducted to estimate the average temperature of the glaciers and the character of the glacier beds using the measured amplitudes and phases of the radar data values for the electrical properties of ice needed to model absorption in the ice reflection amplitudes at the ice base were compiled from the literature and extrapolated down to 5 mhz an ambiguity in the interpretation of the radar data regarding the relative contributions of reflection and absorption losses to the total attenuation could only be resolved by including additional independent information about the glaciers such as 15 m temperatures and evidence for sliding around the perimeter we conclude from these data that both the quelccaya ice cap and the col of huascaran are temperate glaciers which are dry based near their summits and in the case of quelccaya wet based near the margin

addition of magmatic volatiles into the hot spring waters of loowit canyon mount st helens washington usa geochemical studies on cold meteoric waters post 1980 hot spring waters fumarole emissions from the dacite dome and volcanic rocks at mount st helens msh from 1985 to 1989 show that magmatic volatiles are involved in the formation of a new hydrothermal system hot spring waters are enriched in 18o by as much as 2 and display enrichments in d relative to cold waters a well defined isotopic trend is displayed by the isotopic composition of a 400 c fumarole condensate collected from the central crater in 1980 33 d 6 18o of condensate samples collected on the dome and of cold meteoric and hot spring waters the trend indicates that mixing occurs between local meteoric water and magmatic water degassing from the dacite dome between 30 and 70 magmatic water is present in the dome fumarole discharges and 10 magnatic water has been added to the waters of the hydrothermal system relations between cl so4 and hco3 indicate that the hot spring waters are immature volcanic waters formed by reaction of rocks with waters generated by absorption of acidic volcanic fluids in addition the b cl ratios of the spring waters are similar to the b cl ratios of the fumarole condensates 0 02 values of 13c in the hco3 of the hot springs 9 5 to 13 5 are similar to the magmatic value at msh 10 5 and the 3he 4he ratio relative to air in a hot spring water is 5 7 suggesting a magmatic origin for this component

hydrothermal activity and subsoil complexity implication for degassing processes at solfatara crater campi flegrei caldera the solfatara area and its fumaroles are the main surface expression of the vigorous hydrothermal activity within the active campi flegrei caldera system at depth a range of volcanic and structural processes dictate the actual state of the hydrothermal system below the crater the presence of a large variety of volcanic products at shallow depth including pyroclastic fallout ash beds pyroclastic density current deposits breccias and lavas and the existence of a maar related fault system appears to exert major controls on the degassing and alteration behavior adding further to the complexity of this environment variations in permeability and porosity due to subsoil lithology and alteration effects may further influence fluid flow towards the surface here we report results from a field campaign conducted in july 2015 that was designed to characterize the in situ physical temperature humidity and mechanical permeability strength stiffness properties of the solfatara crater subsoil the survey also included a mapping of the surficial hydrothermal features and their distributions finally laboratory measurements porosity granulometry of selected samples were performed our results enable the discrimination of four main subsoils around the crater 1 the fangaia domain located in a topographic low in the southwestern sector 2 the silica flat domain on the western altered side 3 the new crust domain in the central area and 4 the crusted hummocks domain that dominates the north east and south parts these domains are surrounded by encrusted areas reworked material and vegetated soil the distribution of these heterogeneous subsoils suggests that their formation is mostly related to i the presence of the fangaia domain within the crater and ii a system of ring faults bordering it the subsoils show an alternation between very high and very low permeabilities a fact which seems to affect both the temperature distribution and surficial degassing a large range of surface temperatures from 25 up to 95 degrees c has been measured across these surfaces with the hottest spot corresponding to the mud pools the area of new crust formation and the crusted hummocks in the subsoil the distribution of temperature is more complex and controlled by the presence of coarser and more permeable sandy pebbly levels these act as preferential pathways for hot hydrothermal fluid circulation in contrast low permeability fine grained levels act as thermal insulators that remain relatively cold and hinder fluid escape to the surface hot gases reach the surface predominantly along vertical fractures when this occurs mound like structures can be formed by a cracking and healing process associated with significant degassing it is anticipated that the results presented here may contribute to an improved understanding of the hazard potential associated with the ongoing hydrothermal activity within the solfatara crater at this site the permeability of the near surface environment and its changes in space and time can affect the spatial and temporal distribution of gas and heat emission particularly in areas where reduction in permeability occurs it can produce pore pressure augmentation that may result in explosive events

review of the evolution of geochemical monitoring networks and methodologies applied to the volcanoes of the aeolian arc italy abstract fluids discharged from volcanic systems are the direct surface manifestation of magma degassing at depth and provide primary insights for evaluating the state of volcanic activity we review the geochemical best practice in volcanic surveillance based to a huge amount of monitoring data collected at different active volcanoes using both continuous and discontinuous approaches the targeted volcanoes belong to the aeolian arc located in the tyrrhenian sea italy and they have exhibited different activity states during the monitoring activities reported here la fossa cone on vulcano island has been in an uninterrupted quiescent stage characterized by variable solfataric activity in contrast stromboli island has shown a persistent mild explosive activity episodically interrupted by effusive eruptions in 1985 2002 2007 and 2014 panarea island which is the summit of a seamount rising from the seafloor of the southern tyrrhenian sea showed only undersea fluid release the only observable clues of active volcanism at panarea island have been impulsive changes in the undersea fluid release with the last submarine gas burst event being observed in november 2002 the geochemical monitoring and observations at each of these volcanoes has directly involved the volcanic plume and or the fumarole vents thermal waters and diffuse soil degassing depending on the type of manifestations and the level of activity encountered through direct access to the magmatic samples when possible and the collection of as much observable data related to the fluid release as possible the aim has been i to verify the thermodynamic equilibrium condition ii to discern among the possible hydrothermal magmatic marine and meteoric sources in the fluid mixtures iii to develop models of the fluid circulation supported by data iv to follow the evolution of these natural systems by long term monitoring and v to support surveillance actions related to defining the volcanic risk and the evaluation and possible mitigation of related hazards the examples provided in this review article show the close relationships among data analysis interpretation and modeling we particularly focus on describing the fieldwork procedures since any theoretical approach must always be verified and supported by field data rather than just by experiments controlled in laboratory indeed the natural systems involve many variables producing effects that cannot be neglected the monitored volcanic systems have been regarded as natural laboratories and all of the activities have focused on both volcanological research and surveillance purposes in order to ensure that these two goals have overlapped an appendix is also included that explains the scientific approach to the systematic activities regarding geochemical monitoring of volcanic activity

isotopic variation of the hydrothermal system on vulcano island italy the isotopic and chemical composition of thermal waters and the isotopic composition of high temperature fumarolic steam at vulcano island indicate an evolution of the hydrothermal system from its magmatic origin through interaction with rocks and mixing with meteoric water seawater is not a component in this system the isotopic values of the fumaroles indicate a local magmatic composition of 7 to 8 18o and 5 to 15 d the high d values of this vapor may reflect contamination of the magma by connate water the isotopic and chemical composition of water from well w2 indicates the existence of geothermal fluid formed by mixing of hcl and so2 bearing condensates of volcanic origin with groundwater with subsequent evolution via water rock interaction the estimated isotopic composition of the geothermal water is 18o 1 and d 5 local shallow seismic events result in a temporary increase in fracture permeability enabling the mixing of magmatic vapor with groundwater or geothermal water tectonic activity associated with deep structures appears to increase the contribution of magmatic vapor to the fumaroles

time series analysis of high temperature fumaroles monitored on the island of vulcano aeolian archipelago italy abstract the exhalation activity at the la fossa cone vulcano island aeolian archipelago italy has been ongoing for more than 1 century many of the monitored geochemical and geophysical parameters have showed transient variations of energy release the time series analyses of fumarole temperatures presented in this paper enabled the sequence of observations to be defined and information from different monitoring stations to be integrated the motion of fluids feeding the fumaroles of the la fossa cone is driven by the thermal and kinetic energies that balance the seismic and volcanic forces active in the region and the temperatures of the fumaroles reflect the local response of the hydrothermal system to these forces during a 14 year period of observation from 1998 to 2012 fumarole temperatures showed various trends but also cyclic variations characterized by sharp increases the repetition of these variations during periods with different trends indicates that no physical variation occurred from the hydrothermal source to the surface during the analyzed period and after each periodic geochemical crisis the previous thermal conditions were restored although the continuous monitoring of high temperature fumaroles was limited to only a few sites the observed trends characterized the most important fumaroles in the area of vulcano island an evaluation of thermal energy release based on these spatially discrete measurements would be a speculative exercise in thermodynamics but the analyses of the recorded data represent a step forward in interpreting the signals from ongoing volcanic activity and in assessing the seismic risk

changes in heat released by hydrothermal circulation monitored during an eruptive cycle at mt etna italy the shallow vertical temperature profile has been measured in the proximity of an eruptive fissure far about 4 km north northeast from mt etna central craters the monitoring site was a steam heated soil lying between a group of flank fractures on the upper northeast flank of mt etna italy i e on the northeast rift we chose this area because it was close to an eruptive fissure that opened in 2002 and extended from about 2500 to about 1500 m a s l with our aim being to determine a connection between this fracture system and the ongoing volcanic activity heat flux anomalies from the ground from september 2009 to september 2012 were evaluated changes in the hydrothermal release which can be related to variations in volcanic activity are discussed and compared to the published geophysical data the heat flux ranges varied during the pre eruptive from about 7 to 38 w m 2 syn eruptive from about 3 to 49 w m 2 and post eruptive phases with the heat released being lowest at the latter phase from about 1 to 20 w m 2 moreover the heat flux time variation was strongly correlated with the eruption rate from the new southeast crater between january 2011 and april 2012 the migration of magma through active conduits acts as a changing heating source for steam heated soils located above the active fractures our findings suggest that tracking the heat flux above active fractures constitutes a useful investigation field for low cost thermal monitoring of volcanic activity time variations in their emissions could highlight the relationship between a hydrothermal circuit and the local network of fractures possibly indicating variation in the structural weakness of a volcanic edifice continuous monitoring of heat flux combined with a realistic model would contribute to multidisciplinary investigations aimed at evaluating changes in volcano dynamics

double origin of hydrothermal convective flux variations in the fossa of vulcano italy soil temperature measurements can provide information on the distribution of degassing fissures their relationship to the internal structure of the volcano and the temporal evolution of the system at vulcano island italy heat flux from a 3 km deep magma body drives a hydrothermal system which extends across the main fossa crater this heat flux is also associated with variable magmatic gas flow a high density map of soil temperatures was made in 1996 at a constant depth of 30 cm on the central and southern inner flanks of the fossa crater these measurements extended over an area covering about 0 04 km2 across which the heat flux is predominantly associated with a shallow boiling aquifer the map shows that hot zones relate to structures of higher permeability mainly associated with a fissure system dating from the last eruptive cycle 1888 1890 from 1996 to january 2005 we studied the evolution of the heat flux for the high temperature part of the map both by repeating our measurements as part of 14 visits during which temperatures were measured at a constant depth and using data from permanent stations which allowed soil temperatures to be continuously measured for selected vertical profiles these data allowed us to calculate the heat flux and its variation with good precision for values lower than about 100 w m 2 which is generally the case in the study area above 100 w m 2 although the heat flux value is underestimated its variations are recorded with an error less than 10 during the period 1996 2004 two increases in the thermal flux were recorded the first one was related to the seismic crisis of november 1998 which opened existing or new fissures the second in november 2004 was probably due to magma migration and was associated with minor seismic activity

magma budgets and steady state activity of vulcano and stromboli we present three models for magma budget during steady state volcanic activity by which non erupted magma is emplaced as dykes or cumulates or crystallises in place using gas and thermal data we apply our models at vulcano to calculate degassing cooling and crystallisation of magma at a rate of 40 375 kg s 1 within a magma body with an upper surface at a 2 km depth at stromboli we calculate a steady magma supply of 300 1300 kg s 1 to shallow 1 km depths

three dimensional resistivity tomography of vulcan s forge vulcano island southern italy 1 9 525 dc resistivity measurements were taken along 9 profiles crossing the volcanic edifice of la fossa di vulcano the forge of god vulcan in ancient roman mythology vulcano island italy using a total of 958 electrode locations this unique data set has been inverted in 3d by minimizing the l2 norm of the data misfit using a gauss newton approach the true 3d inversion was performed using parallel processing on an unstructured tetrahedral mesh containing 75 549 finite element nodes and 398 208 elements to accurately model the topography of the volcanic edifice the 3d tomogram shows a very conductive body 0 1 s m comprised inside the pietre cotte crater with conductive volumes that are consistent with the position of temperature and co2 anomalies at the ground surface this conductive body is interpreted as the main hydrothermal body it is overlaid by a resistive and cold cap in the bottom of the crater the position of the conductive body is consistent with the deformation source responsible for the observed 1990 1996 deflation of the volcano associated with a decrease of hydrothermal activity

influence of rainfalls on heat and steam fluxes of fumarolic zones six months records along the ty fault soufriere of guadeloupe lesser antilles fumarolic zones are permeable areas where both steam and heat are expelled to the atmosphere surface fluxes and flows which are representative of the intensity of the hydrothermal circulation in depth can be monitored by thermometers thermal infrared cameras spectrometers or condensers however the superficial activity of fumarolic zones can be modified by the meteorological conditions in particular the rainfalls which might result in erroneous estimations from this perspective we developed a set of physical equations to quantify the effects of rainfalls on the thermal behavior of fumarolic zones results were faced to continuous measurements achieved at the ty fault fumarolic zone la soufriere volcano guadeloupe lesser antilles during six months in 2010 using six vertical series of thermometers measuring the heat transfer in the ground and one condenser measuring the rising steam flux results demonstrate that in the absence of rainfalls heat and steam flux reach an equilibrium that is representa tive of the geothermal flux in depth conversely after the rainfalls the cooling of the ground provokes a deepening of the condensation level the related soil temperature drop can be estimated by computing the heat required to warm the infiltrated water up to boiling temperature while the recovery rate is directly linked to the geothermal flux our observations allow defining in which conditions flux are at steady state but also to build a first order numer ical model allowing estimating both the physical parameters of the ground thermal conductivity precipitation efficiency coefficient and surface flux constant and the long term thermal behavior of the hydrothermal system in particular our results predict that the hydrothermal activity must vanish on the zones where the geothermal flux drops under a certain threshold 60 w m 2 at la soufriere the existence of this limit may have strong implications for the precipitation rate of minerals and the possible reactivation of the fumarolic zones during volcanic crises

late aptian cretaceous climate changes in northeastern brazil a reconstruction based on indicator species analysis indval abstract the flora preserved in upper aptian rocks of south america and africa is typical of warm climate conditions and commonly associated with semi arid to arid climate warmth loving conifers of the family cheirolepidiaceae and their pollen classopollis are recorded in upper aptian rocks in most of the south atlantic margin basins however an increase in indicators of humid conditions e g ferns is recorded in most sedimentary basins of brazil the method of indicator species analysis indval was applied as a tool for reconstructing the vegetation during the late aptian the indval index expresses which taxa are strongly associated with particular groups of samples the vegetation reflects climate changes and the indval indices illustrate how the taxa interacted through time and reveal patterns in the changing composition of the vegetation the material studied derives from two well sections drilled through the riachuelo formation in the sergipe basin gtp 17 se angico member 70 samples and gtp 24 se taquari member 108 samples the indicator species are strongly associated with particular stratigraphic intervals indval indices for the angico section indicate seven taxa associated with four intervals viz classopollis classoides interval as 1 callialasporites segmentatus and cicatricosisporites avnimelechi interval as 2 verrucosisporites spp and cicatricosisporites microstriatus interval as 3 araucariacites australis and cyathidites spp interval as 4 values for the taquari section indicate nine taxa associated with four intervals viz classopollis classoides interval ts 1 uesuguipollenites callosus callialasporites segmentatus bennettitaepollenites regaliae cyathidites spp cicatricosisporites spp and araucariacites australis interval ts 2 retitriletes spp interval ts 3 araucariacites australis and verrucosisporites spp interval ts 4 two phases dry and wet are recognized in both sections the dry phase is characterized by high to very high abundance of classopollis classoides a conspicuous change in vegetation is recorded with an increase in ferns and upland flora in particular araucariacites australis a australis is the second most abundant terrestrial palynomorph in the late aptian of south america and africa araucariacites is generally associated with an upland flora and warm and humid climates which may explain its association with fern spores the replacement of classopollis by araucariacites and ferns reflects a change from a dry to wet phase the change in flora may be the result of dislocation of the intertropical convergence zone itcz and a relative sea level rise

stable isotope study of reinjection processes in the larderello geothermal field abstract the effects of reinjected waters on the physico chemical characteristics of the fluids of the larderello vapor dominated geothermal field were monitored using deuterium and oxygen 18 as natural tracers during and after reinjection strong short term variations of the isotopic composition of the steam were observed near the reinjection area these variations were due mainly to mixing between the reinjected and deep components large isotopic fractionations occur at depth during the evaporation of the reinjected water and may affect the evaluation of the recovered fluid using a simple mixing model stable isotope and gas steam ratios are closely correlated in the fluid collected in the monitored wells in agreement with the hypothesis that an effective mixing process occurs at depth accompanied by the formation of a liquid plume subjected to different degrees of evaporation the non linear correlation between isotope and gas steam ratios has been interpreted with a model where the deep areal chemical differences in the original fluids are modified by reinjection

late aptian cretaceous paleoceanography of the south atlantic ocean inferred from dinocyst communities of the sergipe basin brazil the late aptian early cretaceous is a crucial time interval for understanding the paleoceanographic changes in the southern hemisphere oceanographic changes in the emerging south atlantic ocean during this interval are reflected in the stratigraphic distribution of dinoflagellate communities recorded in the muribeca and riachuelo formations of the sergipe basin in northeastern brazil the subtilisphaera community in the lower and middle parts of the section appears to be related to the subtilisphaera ecozone and suggests the onset of tethyan influence in the central south atlantic in a restricted to inner neritic environment the succeeding spiniferites community in the middle part of the section represents the first significant transgression probably of eustatic origin the cyclonephelium exochosphaeridium community in the upper part of the section appears to be related to an oceanic event characterized by intermittent dysoxic anoxic conditions the uppermost part of the section is dominated by the spiniferites community related to a progressive regional transgression and culminating in an open marine fully tethyan environment in the central part of the widening south atlantic

steam output from fumaroles of an active volcano tectonic and magmatic hydrothermal controls on the degassing system at vulcano aeolian arc the results from measurements of extensive parameters steam output and exhaling surface area taken at the crater fumarolic field of vulcano island aeolian arc southern italy are reported along with a detailed description of the measuring method the steam emission rate increased by 1 order of magnitude during the observation time 1983 1995 while its concentration in the released gases was only slightly changed during the same period the total exhaling surface expanded from 50 m2 to more than 2400 m2 and evolved following preferential trends that coincide with the main tectonic structures of the island the observed peaks in steam output show a positive correlation with episodes of volcanic activity unrest the temporal increase of steam output and the observed development in the exhaling surface areas are consistent with a volcano tectonic triggering of the exhaling activity particularly the peaks in the steam output are interpreted as a consequence of degassing from an active magma slowly moving toward the surface

design and operation of a portable digital impulse radar we have constructed a back portable impulse radar instrument that weighs roughly 12 kg can be powered by dry cells and records and stores data digitally the radar is controlled by an on board purpose built microcomputer that ensures simple field operation facilitates modifications and allows unattended operation when investigating time varying targets the transmitting unit is triggered from the receiver via an optical link and generates an electromagnetic wavelet by discharging two high voltage capacitors through back to back silicon controlled rectifiers into a resistively loaded dipole antenna successful field operations carried out during the summers of 1986 and 1987 include depth profiling as well as studies of englacial and subglacial targets on several temperate and sub polar glaciers

geochemical and seismological investigations at vulcano aeolian islands during 1978 1989 both geochemical and geophysical evidence indicates that the activity of the fumarolic system of the fossa crater can be divided into two periods from 1978 to 1983 such activity has been mainly controlled by two competing processes which affect the permeability of the fumarolic system at deep levels 1 rock fracturing induced by faulting and 2 mineral deposition alteration the latter which causes a slow decrease of the permeability at deep levels through clogging of fractures and voids prevailed at the end of this period determining a fluid pressure increment in the deep parts of the system from 1984 to 1989 fluid pressure at deep levels remained persistently high triggering local microseismic swarms furthermore pt conditions much higher than before were attained in the zones where hydrothermal fluids seep into the conduits from lateral aquifers owing to an uprising of the isotherms a deepening of these seeping zones or both

paleoenvironment reconstruction of parnaiba basin north brazil using indicator species analysis indval of devonian microphytoplankton abstract the microphytoplankton record of parnaiba basin is typically of devonian age and commonly associated with changes in marine environments the method of indicator species analysis indval was applied as a tool for reconstructing marine environment changes during the devonian pragian famennian the indval expresses which taxa are strongly associated with particular groups of samples the devonian microphytoplankton distribution reflects the paleoenvironment and the indval indices illustrated how the taxa interacted through time and reveals patterns in the changing composition of the microphytoplankton the material studied derives from three well sections arn 12 samples na 22 samples and lt 13 samples drilled through the itaim pimenteira and cabecas formations in the parnaiba basin respectively samples were prepared using the standard palynological method the indicator species coincidently are age diagnostic for the devonian succession the indval indicates fourteen taxa viz schizocystia saharica triangulina alargada bimerga paulae pragian emsian interval onondagella asymetrica tunisphaeridium tentaculiferum estiastra spp early givetian interval mediocorpore conspicuus unattributed species of unellium frasnian 1 interval petrovina connata unattributed species of acriora frasnian 2 interval winwaloeusia distracta unattributed species of stellinium frasnian 3 interval arkonites bilixus and unattributed species of duvernaysphaera frasnian famennian interval microphytoplankton typical of more nearshore settings are recorded in the basal interval pragian emsian interval accompanied by high values of phytoclasts and continental marine ratio c m a change in microphytoplankton is recorded with an increase in acritarchs and prasinophycean algae typical of open marine conditions in particular during the frasnian 3 interval the change reflects sea level rise

multiparametric approach in investigating volcano hydrothermal systems the case study of vulcano aeolian islands italy seismic activity ground deformation and soil and fumarole temperatures acquired during 2004 2007 at vulcano aeolian islands are analysed and the time relations among the different time series are discussed changes in temperature of fumarolic gases took place during four anomalous periods november 2004 march 2005 october 2005 february 2006 august october 2006 july december 2007 at the same time as an increasing number of volcano seismic events in particular the temperatures at high temperature vents and at steam heated soil ranged in time from 180 to 440 c and from 20 to 90 c respectively the maximum daily number of volcano seismic events was 57 reached during the second anomalous period this seismicity characterised by focal depth generally lower than 1 km below sea level b s l and composed of different kinds of events associated to both resonance and shear failure processes is related to the shallow dynamics of the hydrothermal system during the analysed period very few volcano tectonic earthquakes took place and tilt recordings showed no sharp or important changes in light of such observations the increases in both temperature and volcano seismic events number were associated to increases in the release of gas from a deep and stable magma body without magma intrusions within the shallow hydrothermal system indeed a greater release of gas from depth leads to increased fluid circulation that can promote increases in volcano seismic events number by both fracturing processes and resonance and vibration in cracks and conduits the different trends observed in the measured geochemical and geophysical series during the anomalous periods can be due to either time changes in the medium permeability or a changing speed of gas release from a deep magma body finally all the observed variations together with the changing temporal distribution of the different seismic event kinds suggest that the hydrothermal system at vulcano can be considered unsteady and dynamic

thermal and gas dynamic investigations at lastarria volcano northern chile the influence of precipitation and atmospheric pressure on the fumarole temperature and the gas velocity abstract fumaroles are hydrothermal manifestations commonly associated with active volcanoes the dynamics of fumaroles are affected by interactions with internal and external factors however hazardous access and corrosive gases have so far limited successful case studies in this study we report and discuss the results of continuous thermal monitoring carried out on three high temperature 250 c fumaroles at the lastarria volcano chile together with simultaneously measured meteorological parameters from december 2013 to march 2016 in addition the dynamic pressure and the co2 concentration were recorded in a fourth vent the investigated sites are located in the largest and most dominant fumarole field which developed in a fracture system on the north west flank of the volcanic edifice we detect external factors controlling the fumarole temperature and the dynamic gas pressure for a better understanding of changes in these parameters and consequently to improve the evaluation of volcanic and hydrothermal activity selected fumaroles showed a continuous decrease in temperature or remained unbiased from this trend showing that the influence of external effects on outlet temperature is strongly site dependent but generally significant decreases in all vent temperatures can be observed in response to intensive precipitation diurnal variations occur only in the coolest fourth fumarole where gas temperature gas pressure and co2 concentration are inversely correlated with atmospheric pressure small barometric pressure reductions account for an increase in mass flow subsequently resulting in a higher temperature and co2 concentration the temperatures and thermodynamic properties of the fumarolic gas and infiltrated precipitation water were used to calculate the amount of discharging gas from the investigated field with about 67 106 m3 per day which is equivalent to 3545 tons

transient self potential anomalies associated with recent lava flows at piton de la fournaise volcano reunion island indian ocean self potential signals are sensitive to various phenomena including ground water flow streaming potential thermal gradients thermoelectric potential and potentially rapid fluid disruption associated with vaporization of water we describe transient self potential anomalies observed over recent 9 years lava flows at piton de la fournaise volcano reunion island indian ocean repeated self potential measurements are used to determine the decay of the self potential signals with time since the emplacement of a set of lava flow we performed a 9 km long self potential profile in february 2004 in the grand brule area this profile was repeated in july august 2006 the second repetition of this profile crossed eight lava flows emplaced between 1998 and 2005 during seven eruptions of piton de la fournaise volcano the self potential data show clear positive anomalies up to 330 mv and spatially correlated with the presence of recent lava flows the amplitude of the self potential anomalies decreases exponentially with the age of the lava flows with a relaxation time of not vert similar 44 months we explain these anomalies by the shallow convection of meteoric water and the associated streaming potential distribution but we cannot exclude possible contributions from the thermoelectric effect and the rapid fluid disruption mechanism this field case evidences for the first time transient self potential signals associated with recent volcanic deposits it can be also a shallow analogue to understand the variation of self potential signals in active geothermal areas and transient self potential signals associated with dike intrusion at larger depths the empirical equation we proposed can also be used to diagnose the cooling of recent lava flow on shield volcanoes

reconstructing the vulcano island evolution from 3d modeling of magnetic signatures abstract high resolution ground and marine magnetic data are exploited for a detailed definition of a 3d model of the vulcano island volcanic complex the resulting 3d magnetic imaging obtained by 3 d inverse modeling technique has delivered useful constraints both to reconstruct the vulcano island evolution and to be used as input data for volcanic hazard assessment models our results constrained the depth and geometry of the main geo structural features revealing more subsurface volcanic structures than exposed ones and allowing to elucidate the relationships between them the recognition of two different magnetization sectors approximatively coincident with the structural depressions of piano caldera in the southern half of the island and la fossa caldera at the north suggests a complex structural and volcanic evolution magnetic highs identified across the southern half of the island reflect the main crystallized feeding systems intrusions and buried vents whose nnw sse preferential alignment highlights the role of the nnw sse tindari letojanni regional system from the initial activity of the submarine edifice to the more recent activity of the vulcano complex the low magnetization area in the middle part of the island may result from hydrothermally altered rocks their presence not only in the central part of the volcano edifice but also in other peripheral areas is a sign of a more diffuse historical hydrothermal activity than in present days moreover the high magnetization heterogeneity within the upper flanks of la fossa cone edifice is an imprint of a composite distribution of unaltered and altered rocks with different mechanical properties which poses in this area a high risk level for failure processes especially during volcanic or hydrothermal crisis

new geological insights and structural control on fluid circulation in la fossa cone vulcano aeolian islands italy accepted 1 june 2009 available online 21 june 2009 keywords electrical resistivity self potential soil co2 degassing temperature fluid circulation hydrothermal system structural boundary vulcano la fossa cone electric resistivity tomography ert self potential sp soil co2 ux and temperature are used to study the inner structure of la fossa cone vulcano aeolian islands nine profiles were performed across the cone with a measurement spacing of 20 m the crater rims of la fossa cone are underlined by sharp horizontal resistivity contrasts sp co2 flux and temperature anomalies underline these boundaries which we interpret as structural limits associated to preferential circulation of fluids the pietre cotte crater and gran cratere crater enclose the main hydrothermal system identified at the centre of the edifice on the base of low electrical resistivity values b20 m and strong co2 degassing sp and temperature anomalies in the periphery the hydrothermal activity is also visible along structural boundaries such as the punte nere forgia vecchia and palizzi crater rims and at the base of the cone on the southern side of the edifice along a fault attributed to the nwmain tectonic trend of the island inside the punte nere crater the ert sections show an electrical resistive body that we interpret as an intrusion or a dome this magmatic body is reconstructed in 3d using the available ert profiles its shape and position with respect to the pietre cotte crater fault allows replacing this structure in the chronology of the development of the volcano it corresponds to a late phase of activity of the punte nere edifice considering the position of the sp soil co2 flux and temperature maxima and the repartition of conductive zones related to hydrothermal circulation with respect to the main structural features la fossa cone could be considered as a relevant example of the strong influence of preexisting structures on hydrothermal fluid circulation at the scale of a volcanic edifice

volcano surveillance using infrared cameras abstract volcanic eruptions are commonly preceded accompanied and followed by variations of a number of detectable geophysical and geochemical manifestations many remote sensing techniques have been applied to tracking anomalies and eruptive precursors and monitoring ongoing volcanic eruptions offering obvious advantages over in situ techniques especially during hazardous activity whilst spaceborne instruments provide a distinct advantage for collecting data remotely in this regard they still cannot match the spatial detail or time resolution achievable using portable imagers on the ground or aircraft hand held infrared camera technology has advanced significantly over the last decade resulting in a proliferation of commercially available instruments such that volcano observatories are increasingly implementing them in monitoring efforts improved thermal surveillance of active volcanoes has not only enhanced hazard assessment but it has contributed substantially to understanding a variety of volcanic processes drawing on over a decade of operational volcano surveillance in italy we provide here a critical review of the application of infrared thermal cameras to volcano monitoring following a summary of key physical principles instrument capabilities and the practicalities and methods of data collection we discuss the types of information that can be retrieved from thermal imagery and what they have contributed to hazard assessment and risk management and to physical volcanology with continued developments in thermal imager technology and lower instrument costs there will be increasing opportunity to gather valuable observations of volcanoes it is thus timely to review the state of the art and we hope thereby to stimulate further research and innovation in this area

vegetation development in an amazonian peatland recent investigations of wetlands in western amazonia have revealed the presence of extensive peat deposits up to 7 5 m thick developing under a variety of vegetation types we report the first attempt to establish the long term centennial to millennial scale vegetation history of one of these peatland sites quistococha a palm swamp close to iquitos in northern peru pollen and sedimentological analyses show that peat formation began at the core site under sedge fen or floating mat vegetation c 2200 calendar years before present cal yr bp a seasonally flooded woodland developed c 1880 cal yr bp the permanently waterlogged palm swamp which persists today began to form c 1000 cal yr bp with the present vegetation community established by c 400 years ago the vegetation at this site has undergone continuous change throughout the period of peat formation with several abrupt transitions and reversals and repetitions in the apparent trajectory of change the pollen data combined with sedimentary evidence suggest that the dominant control on ecosystem functioning and development is the flooding regime there appears to have been a decrease in fluvial influence over time there is no clear evidence of direct climatic or anthropogenic influence although we cannot rule out the possibility of climatically driven hydrological changes our results caution against adopting a simple model of peatland vegetation succession in this region

palynofacies in a late silurian regressive sequence in the welsh borderland and wales the upper whitcliffe and lower part of the downton castle sandstone formations ludlow and pridoli series have been sampled from sequences distributed over an area roughly 4800 square km in west central england and wales ludfordian age rocks have been interpreted as the deposits of shelf and basin environments and those of the lower downton group as near shore to beach sections sampled from the shelf area are in the ludlow type area and in the usk may hill and woolhope inliers basin sediments were sampled at knighton the long mountain capel horeb and kington the samples were analysed for their palynological content and all the organic walled microfossils were studied together with the fragmentary remains of larger plants and animals using a series of ratios between different groups of microfossils it is apparent that there are consistent changes through time in both the palynomorph assemblages and in the structured and unstructured organic material dominance of some microplanktic groups taxa is used to define a new microphytoplanktic phase concept and to compare the sequence of palynoevents depositional environments inferred from palynofacies interpretation of the ludlow type area are closely comparable with those proposed previously from sedimentological data palynofacies sequences differ for the shelf and basin areas but show similar trends we have also recognized a dramatic shift in palynofacies at a level within the downton castle sandstone formation and its correlatives in both shelf and basin areas this change is tentatively interpreted as a storm event

early to middle devonian ironstone and phosphorite in the northwestern gondwana parnaiba basin brazil a record of an epeiric margin paleoceanographic changes abstract pragian to givetian successions in the caninde group parnaiba basin brazil present phosphorites ironstone and organic rich sediments that globally coincide with greenhouse conditions and an increase in continental weathering ocean oxygen levels and black shale deposition events these facies are associated with the evolution of the northern gondwana epeiric sea margin of the rheic ocean and can tell us how ocean chemistry changed and the paleoceanographic factors involved in this particular transition of the ocean record we conducted an integrated study based on sedimentology sequence stratigraphy petrography scanning electron microscopy and x ray diffraction to understand the paleoenvironmental stratigraphic and diagenetic controls lithofacies stacking patterns indicate that deposition occurred during marine transgressions resulting in four depositional sequences late eifelian and givetian maximum flooding surfaces are represented by phosphogenesis and francolite precipitation associated with condensed zones pragian emsian to givetian ironstones were represented by authigenic coated phosphatic iron silicate odinite chamosite clinochlore francolite and siderite precipitation these are related to normal regressions under lowstand and highstand systems tract oxic waters prevailed and episodic upwelling is interpreted as the source of nutrients that maintained fe si and p supply on a storm influenced to storm dominated shelf with an additional source of iron also associated with river discharges phosphorite was formed in a stratified ocean near storm wave base under anoxic sulfide reducing bacteria microbial communities and suboxic conditions productivity fueled by recycled p shallower anoxic conditions near the fair weather wave base existed possible related to a shift in the locus of upwelling and then resumption to oxic conditions indicate that water column stratification was not a stable feature due to variations in base level ventilation terrigenous or marine contribution and progressive microbial degradation at the beginning of late eifelian transgression an event of increased delivery of continental flux and eutrophication can also be proposed the link between organic rich intervals and third order black shale events daleje chot c and kacak suggests that extinction events can be tracked by analyzing sections in south america global correlation with ironstone precipitation and organic rich sediments shows that stepped periods of c sink conditions probably contributed to the ocean oxygenation

joint analysis of electric and gravimetric data for volcano monitoring application to data acquired at vulcano island southern italy from 1993 to 1996 abstract understanding the dynamics of volcanic hydrothermal systems is a key factor for discriminating between magmatic and hydrothermal nature of the sources responsible for the unrest phenomena observed in active volcanic areas numerous studies of geophysical data monitoring in volcano geothermal districts has indeed proven that close relationships exist between the volcanic and hydrothermal fluid circulation and the anomalous geophysical signals observed at the ground surface in this paper a simultaneous analysis that integrates resistivity and gravity data is suggested as a useful tool to infer a consistent conceptual model of hydrothermal volcanic systems and their evolution an application of the proposed analysis to repeated resistivity and gravity measurements performed on vulcano island aeolian archipelago sicily southern italy is presented with the aim of gaining information on the dynamics of the volcanic hydrothermal system the examined period ranges from december 1993 to september 1996 when significant changes in chemical properties temperatures and emission rates of la fossa crater fumaroles were observed all indicating an increase in the flux of hot deep magmatic gases the results of our analysis which refers to a profile located at the foot of the northwest flank of la fossa cone suggest that underground cyclic water to vapour transformations govern the shallow hydrothermal system dynamics generally described by a negative correlation between the monitored resistivity and gravity data the occurrence of positive correlations between the two analysed parameters could be ascribed to volcanic dynamics which would mask the normal hydrological and hydrothermal system behaviour

determination of sensible heat flux in volcanic areas from ground temperature measurements along vertical profiles the case study of mount etna sicily italy measurements of ground temperature at shallow depth continuously transmitted and stored in a data base can be of value to follow volcanic events and to give information about heat flux at the surface of the volcano we propose models to calculate heat flux from temperature measurements for the following cases conductive transfer convective transfer and conductive and convective transfer then we examine the results obtained in the summit area of mount etna in convective areas it is difficult to estimate the flux in the absence of complementary information about the liquid content of the outgoing fluid but the steady flux is more important than the unsteady one at the torre del filosofo station the transfer is conductive it can be used as a reference station and geothermal heat flux can be approached

thermal surveys of the vulcano fossa fumarole field 1994 1999 evidence for fumarole migration and sealing abstract between 1994 and 1999 we carried out five thermal surveys of the vulcano fossa fumarole field each consisted of 485 1213 vent temperature measurements distributed across the field these show that the field has been cooling and expanding where mean and maximum vent temperatures decreased from 216 to180 c and 541 to 428 c respectively between 1994 and 1997 however expansion of the field resulted in increased heat loss from 45 to 67 mw we suggest that cooling and expansion has been caused by increased gas flux and or permeability where increased flow of fluids of magmatic origin during 1996 is implied by chemical and isotopic data capasso g favara r francofonte s inguaggiato s 1999 chemical and isotopic variations in fumarolic discharge and thermal waters at vulcano island aeolian islands italy during 1996 evidence of resumed volcanic activity j volcanol geotherm res 88 1999 167 175 we propose that the size of the conduit has increased causing the fumarole field to expand and vent temperatures to generally decline as gas and heat losses become distributed over a wider area the increase in exhaling area has outweighed the modulating effect of cooling on total heat losses so that heat loss has increased due to an increased input from the magmatic source and or an increase in system permeability within these field wide trends the rim and then the middle zones have been cooling conversely the lower zone showed evidence of warming during 1994 98 before cooling in 1999 throughout the measurement period a se s thermal migration has been apparent and a new hot zone has developed on the field s southern edge we suggest that sealing of fumaroles by complete boiling of marine fluids on the northern edge of the system and higher permeability on the southern edge may have influenced this expansion direction if vent temperatures drop below 100 c then shallow sulfur sealing will quickly diminish fumarole life expectancy and contribute to the abandonment of vents in cooling zones in our model increased gas flux and or permeability e g due to increased magmatic degassing and or fracturing is the primary mechanism driving observed changes in the field temperature size and location deep and shallow conduit sealing are secondary mechanisms influencing the location of new zones once increased gas and heat fluxes have been triggered

long term monitoring on a closed conduit volcano a 25 year long time series of temperatures recorded at la fossa cone vulcano island italy ranging from 250 c to 520 c abstract the longest record of temperature data from an active volcano in southern italy is presented the dataset comes from continuous monitoring of fumarole temperatures from the la fossa cone of vulcano aeolian islands running from 1991 to 2016 the discussion includes an empirical approach based on a large number of direct measurements at vulcano island geochemical monitoring of the uprising fluids allows detection of the surface effects of perturbation in the state variables of the buried hydrothermal and magmatic systems the presented datasets show that fumaroles changing temperatures which are related to surface heat flow are useful indicators over the past 25 years the combined effects of runoff and chemo physical alterations were negligible on the output temperature of the earliest monitored fumaroles the maximum recorded variation was 298 c measured in the ground very close to the steaming vents at a depth of 0 5 m repetition of output temperature values occurred after 19 years in the same position the time variations suggest a cyclic characteristic although more years are needed to register the complete cyclic modulation a combination of minor cyclical variations has also been registered in the fumarole output the minor cycles appeared in this long series of data after 1995 and they can be interpreted as one of the surface effects of temporary departures from a stationary state assumed for the system feeding the la fossa area in this sector of the mediterranean area the steady state pressure field as well as the steady state temperature gradients can be perturbed either by magmatism or by seismo tectonic processes related to regional dynamics this long term monitoring allowed comparisons of many temperature subsets with other validated geochemical and geophysical data series and highlighted common source mechanisms accounting for endogenous processes changes in the magma source and or seismo tectonic activity have been the primary causes of the time variations the collected data show the effectiveness of the geochemical approach for following the heat flow changes that originated from a deep source in real time even though an estimation of magmatic and or hydrothermal energy release cannot be retrieved by surface temperature monitoring alone

seismic signals in geothermal areas of active volcanism a case study from la fossa vulcano italy since the last eruption 1888 1890 volcanism at vulcano aeolian archipelago southern tyrrhenian sea has taken the form of persistent fumarolic activity the gas vapour phases of the geothermal systems are mainly discharged within two restricted areas about 1 km apart from each other in the northern part of the island these areas are la fossa crater and the beach fumaroles of the baia di levante fluids released at the two main fumarolic fields display quite different chemical and temperature characteristics implying different origins the local seismicity essentially takes the form of discrete shocks of shallow origin depth 1 km at la fossa usually with energy 1013ergs they are thought to be related to the uprise of pressurized hot gases and vapours discharged at the crater fumaroles the present investigation points to the existence of two principal categories of seismic events called m shocks and n shocks these are short events normally 10 s m type shocks are thought to be due to resonance vibrations within the interior of the volcano probably driven by the excitation of shock waves within cavities deeply affected by deposition and alteration of self sealant hydrothermal minerals n type events display features that resemble those of volcano tectonic earthquakes but have no recognizable s phases here they are tentatively attributed to microfracturing of rocks which have been extensively hydrothermally altered results of the present study permit a preliminary conceptual model of the local shallow seismic processes in the framework of geochemical modelling of fumarolic activity and geological inferences from geothermal drilling

depositional environment and maturity of devonian pimenteira formation in the sao luis basin brazil abstract we carried out a detailed organic facies study on shale cutting samples from the devonian pimenteira formation in the sao luis basin northwest brazil to reconstruct the depositional paleoenvironment and origin of the organic matter samples were collected from the stratigraphic well 2 anp 5 ma and were analyzed for total organic carbon toc total sulfur s insoluble residue ri spore coloration index sci vitrinite reflectance ro palynofacies and biomarkers the toc values of the analyzed sediments range from 0 19 to 0 51 s from 0 17 to 0 85 and the total carbonate caco3 is low

scale dependent location of hydrothermal vents stress field models and infrared field observations on the fossa cone vulcano island italy article i nfo hydrothermal venting occurs on numerous volcanoes of various age setting topographic and structural expression vent locations are commonly found not within volcanic craters only but predominantly at the crater margins and topographic highs a case example is vulcano island italy where the control on such vent locations along crater margins remained poorly understood however this paper describes numerical models combined with field observations and infrared imaging to explore the mechanisms that control the ascent paths of fluids in the fossa cone on vulcano using finite element modelling we calculate the gravitational stress in the volcanic edifice imposed by the topography results predict hydrofractures to be arranged in radial patterns at depth and in concentric patterns close to the surface furthermore low compressive stress values are found at the rims of the nested craters we compare the stress models to fumarole field data using a forward looking infrared camera we recorded images of the entire cone images were assembled to a mosaic and geocoded providing the first map of a remotely sensed temperature field in high resolution at la fossa the degassing and high temperature anomalies are found to be located mainly at the crests of the craters predominately in the northern and southern sector of the main crater therefore the stress distribution favours and indeed corresponds to the occurrence of fumaroles at la fossa the stress models also yield compression at the bottom of the crater where temperatures are cool thus we consider that the overall distribution of the fumaroles at the fossa cone is controlled by topography additional mechanisms contribute to the exact position of the degassing sites the influence of the lithological control seems to be strong in the southwestern part of the crater where the fumaroles are located 10 20 m below the inner crater rim in bedded strata in the northern part of the crater the exhalation sites can mainly be found at surface fractures and cracks emphasizing the structural control on the location of the fumaroles at this sector of the fossa cone using combined theoretical modelling and field observations this study helps to shed light into the processes directing fluids in volcanic edifices elsewhere and might contribute to the evaluation of upcoming hazard scenarios

isotope composition of rain water well water and fumarole steam on the island of vulcano and their implications for volcanic surveillance abstract water samples from eight wells in the vulcano porto area and fumarole steam from the crater of vulcano southern italy were collected at monthly intervals over a two year period from february 1987 to january 1989 samples of bulk precipitation were also collected in three points at vulcano porto and vulcano piano island of vulcano and castroreale tyrrhenian coast of sicily again at monthly intervals the weighted mean isotopic composition of rain water on vulcano is d 32 and d 18 o 6 4 results for well waters tend to support the existence of at least two water bodies one of purely meteoric water and the other of brackish thermal water an intermediate water body probably the result of mixing of the other two was also recognized the isotope composition of fumarolic steam from the crater suggests the mixed contribution of both sea and rain waters although mixing is not the only process occurring the existence of a deep marine brine body is inferred characterized by d and 18o values more positive than those of mediterranean sea water a close relationship indicating common source effects is shown by temporal isotopic variations at some wells and the fumarolic steam wich may be used for volcano survey at distance from the active crater

spatio temporal evolution of temperature and fluid flow through a new thermo lithological boundary the case of a pit crater of karthala volcano comoros archipelago refilled on january 13th 2007 by a lava flow on january 13 th 2007 the effusive eruption of karthala volcano in the comoros islands emitted a lava flow which has been perfectly constrained inside the cylindrical shape of the choungou chagnoumeni pit crater 225m in diameter and with a thickness of about 7m the good knowledge of the geometry of this lava flow allowed modeling its cooling with the rheolef code with a good accuracy the results of the thermal modeling were compared with other measurements performed on the field 1 a high resolution electrical resistivity tomography profile crossing the boundary of the crater and 2 the thermal monitoring of temperature with eleven sensors spaced 1 meter apart at 30 cm depth perpendicularly to the boundary of the crater thanks to this multidisciplinary approach it has been possible to display that in the first order the resistivity distribution in the soil 2 years and 5 months after the eruption is directly influenced by the residual temperature and not by the structural boundary during the first three years of cooling an inversion in the shallow lateral temperature gradient was observed in temperature data set collected at 30 cm depth

vent temperature trends at the vulcano fossa fumarole field the role of permeability between 1994 and 2010 we completed 16 thermal surveys of vulcano s fossa fumarole field aeolian islands italy in each survey between 400 and 1 200 vent temperatures were collected using a thermal infrared thermometer from distances of 1 m the results show a general decrease in average vent temperature during 1994 2003 with the average for the entire field falling from 220 c in 1994 to 150 c by 2003 however between 2004 and 2010 we witnessed heating with the average increasing to 190 c by 2010 alongside these annual scale field wide trends we record a spatial re organisation of the fumarole field characterised by shut down of vent zones towards the crater floor matched by rejuvenation of zones located towards the crater rim heating may be expected to be associated with deflation because increased amounts of vaporisation will remove volume from the hydrothermal system gambino and guglielmino j geophys res 113 b07402 2008 however over the 2004 2010 heating period no ground deformation was observed instead the number of seismic events increased from a typical rate of 37 events per month during 1994 2000 to 195 events per month during 2004 2010 as part of this increase we noticed a much greater number of high frequency events associated with rock fracturing we thus suggest that the heating event of 2004 2010 was the result of changed permeability conditions rather than change in the heat supply from the deeper magmatic source within this scenario cooling causes shut down of lower sectors and re establishment of pathways located towards the crater rim causing fracturing increased seismicity and heat flow in these regions this is consistent with the zone of rejuvenation which lies towards and at the rim being the most favourable location for fracturing given the stress field of the fossa cone schopa et al j volcanol geotherm res 203 133 145 2011 it is also the most established zone having been active at least since the early twentieth century our data show the value of deploying multi disciplinary geophysical campaigns at degassing fumarolic hydrothermal systems this allows more complete and constrained understanding of the true heat loss dynamics of the system in the case study presented here it allows us to distinguish true heating from apparent heating phases while the former are triggered from the bottom up i e they are driven by increases in heat supply from the magmatic source the latter are triggered from the top down i e by changing permeability conditions in the uppermost portion of the system to allow more efficient heat flow over zones predisposed to fracturing

heat flux measurement from thermal infrared imagery in low flux fumarolic zones example of the ty fault la soufriere de guadeloupe monitoring the geothermal flux of a dormant volcano is necessary both for hazard assessment and for studying hydrothermal systems heat from a magma body located at depth is transported by steam to the surface where it is expelled in fumaroles if the heat flow exceeds 500 w m2 if the heat flow is lower than 500 w m2 steam mainly condensates in the soil close to surface and produces a thermal anomaly detectable at the surface in this study we propose a method to quantify low heat fluxes from temperature anomalies measured at the surface by a thermal infrared camera once corrected from the atmospheric and surface effects thermal infrared images are used to compute 1 the excess of radiative flux 2 the excess of sensible flux and 3 the steam flux from the soil to the atmosphere these calculations require measurements of atmospheric parameters temperature wind velocity and humidity and estimations of surface parameters roughness and emissivity this method has been tested on a low flux fumarolic zone of the soufriere volcano guadeloupe island lesser antilles and compared to a flux estimation realized from the thermal gradient measurements into the soil the two methods show a good agreement and a similar precision 267 46 w m2 for the thermal infrared method and 275 50 w m2 for the vertical temperature gradient method if surface roughness is well calibrated

time variability of low temperature fumaroles at stromboli island italy and its application to volcano monitoring the constant and mild activity of stromboli volcano italy is occasionally interrupted by effusive events and or more energetic explosions referred to as major explosions and paroxysms which are potentially dangerous for the human community although several premonitory signals for effusive phases have been identified precursors of major explosions and paroxysms still remain poorly understood with the aim of contributing to the identification of possible precursors of energetic events this work discusses soil temperature data acquired in low temperature fumaroles at stromboli in the period 2006 2010 data analysis revealed that short term anomalies recorded in the thermal signal are potentially useful in predicting state changes of the volcano in particular sudden changes in fumarole temperatures and their hourly gradients were observed from several days to a few hours prior to fracturing and paroxysmal events heralded by peculiar waveforms of the recorded signals the qualitative interpretation is supported by a quantitative theoretical treatment that uses circuit theory to explain the time dependence of the short period temperature variations showing a good agreement between theoretical and observational data

middle to late miocene caribbean dinoflagellate assemblages and palynofacies dsdp leg 15 site 153 abstract changes in oceanic circulation and productivity patterns near central america have been explained using numerous different tools such as tectonics geochemistry and micropaleontology this paper aims to contribute to this discussion through the study of dinoflagellates and palynofacies in the drill core from dsdp site 153 based on foraminiferal data the studied section is divided into the middle and upper miocene and our dinoflagellate events also support an age model of 15 to 8 ma indval ecological indexes and the p g dinoflagellate ratios were used to develop paleoenvironmental inferences the indicator species are operculodinium centrocarpum and tectatodinium pellitum for the mm1 interval spiniferites spp and impagidinium strialatum for mm2 and selenopemphix armageddonensis lejeunecysta spp and l tenella for um3 intervals mm1 and mm2 are characterized by a dominance of gonyaulacoids and inner to outer neritic environments the um3 interval is interpreted as an outer neritic environment in the base middle portion and inner neritic in the uppermost part with a shift from gonyaulacoid to peridinioid dominance suggesting an increase in productivity during the middle miocene productivity is low due to intermittent marine circulation restrictions in the caribbean sea and there is a slight increase during the upper miocene following reestablishment of the global oceanic circulation this is directly connected to the occurrence of geotectonic and paleoceanographic events in the region during the miocene mainly by mass movements such as the panama gateway and the opening of the pedro channel to the north changing the surface conditions in the caribbean sea

permeable convection above magma bodies abstract thermal convection above large shallow magma bodies in the crust is treated as a one dimensional bottom heated convection process in permeable media solutions for single phase convection are briefly reviewed and a solution is developed for two phase permeable convection in bottom heated media heat flow measurement techniques are discussed for permeable geologic zones above magma bodies and these techniques give consistent results for solidifying lava lakes in hawaii kilauea iki q 257 w m2 and iceland heimaey q 465 w m2 the heat loss from a magma body is a strong function of the permeability when a two phase convection zone occurs above the magma body and the heat loss is independent of the thickness of the two phase convection zone in steady state two phase convection zones where permeability does not vary appreciably with depth convective heat flow restrictions tend to limit the maximum saturation temperatures at depth to around 250 c an effect observed in many geothermal steam fields a conduction dominated transition zone tends to occur between the two phase zone and the magma body and the thickness of this transition zone may easily range from a few meters to several kilometers depending on the permeability

practical evaluation of steady heat discharge from dormant active volcanoes case study of vulcarolo fissure mount etna italy abstract from a theoretical approach combined with experimental study i propose a method to compute both sensible and latent heat transfer in a thermally active volcanic area this method is applied to a fumarolic thermal fissure located on the south flank on mount etna italy the method involves four steps 1 mapping of self potential sp to quickly identify thermal anomalies 2 mapping of ground temperature t at constant depth in the area defined by sp mapping 3 measurement of vertical t profiles at selected representative stations including the coldest and hottest and 4 direct measurements of vapor flow where the convective heat flux reaches the surface when heat flux values vary in the range 10 300 w m 2 t measurements at a depth equal to about 1 m are sufficient to estimate the absolute flux value to within an absolute error less than 30 and 10 for the relative value ground temperature measurement is an easy and accurate method for estimating heat discharge on a limited surface to define the fissure system monitor time variations of heat flux or to calibrate remote sensing results on the ground

stable isotope evidence for a magmatic component in fumarole condensates from augustine volcano cook inlet alaska u s a abstract d h and 18 o 16 o ratios have been determined for fumarole condensates from augustine volcano an active calc alkaline stratovolcano in lower cook inlet alaska the isotopic data for the condensates form a linear d 18 o array from low temperature fluids d 150 18 o 19 to high temperature 450 c fluids collected at the volcano summit which are enriched in both d and 18 o d 35 18 o 3 5 several lines of evidence suggest that the d and 18 o rich condensates likely are magmatic fluids released into the hydrothermal system during and immediately after the 1976 eruption prior to 1976 the augustine hydrothermal system was dominated completely by local meteoric waters between 1976 and 1982 fumarole condensates were observed to be variable mixtures of the magmatic fluid and meteoric water with the proportion of the former systematically decreasing as the hydrothermal system cooled following the 1976 eruption

geochemical modeling of mixing between magmatic and hydrothermal gases the case of vulcano island italy abstract in this study we present a geochemical approach to model the mixing of magmatic and hydrothermal gases our model is based on a rigorous formulation of a perfectly dimensioned system of mass and energy balance equations inputs of the equation set are the h2o and co2 content and gas emission temperature at the surface together with some constraints gained from the chemical physical features of the hydrothermal system the output data give the composition of magmatic gas mixing fractions and temperatures of gas mixtures in the mixing zone the comparison of the emission temperature of fumarolic gases with their calculated mixing temperatures provides valuable indications on the expansion process that gases undergo during their ascent towards the surface our mixing model is exemplified by the fumarolic system of vulcano island italy we calculate the thermodynamic parameters of the hydrothermal system by means of an h2o co2 nacl equation of state while the thermo baric conditions of the magma have been assessed by previous geophysical and petrologic investigations the obtained results show that during volcanic crises at vulcano island and in agreement with magma degassing processes both the co2 and the he contents of magmatic gas display peaks with a progressively declining amplitude suggesting a progressive magmatic impoverishment of volatiles strongly partitioned in the gas phase mixing fractions of various fumaroles are normally variable while they display almost homogeneous values during periods of increased volcanic activity on the basis of results gained some implications regarding the hazard of phreato magmatic explosions are also discussed the high temperature reached by fumarolic gases strongly constrains their probable expansion process during the ascent towards the surface a comparison between the temperature of the fumarolic gas and the calculated mixing temperature at depth indicates that the expansion process can be reasonably described as almost iso enthalpic although field evidences suggest that the fumarolic emission temperature could be affected by the sharp permeability changes in the last few hundred meters therefore our results and field evidences clearly indicate that variations in gas emission temperature cannot be considered a good indicator of volcanic activity as it is strongly dependent on expansion process and ultimately on rock permeability changes the model greatly improves the knowledge of the volcanic system of vulcano island and provides an important tool for the interpretation and evaluation of volcanic activity moreover a similar approach can be considered for other volcanic systems having analogous characteristics