co2 emissions related to the yellowstone volcanic system 2 statistical sampling total degassing and transport mechanisms a stratified adaptive sampling plan was designed to estimate co2 degassing in yellowstone national park and was applied in the mud volcano thermal area the stratified component of the sampling design focused effort in thermal areas and the adaptive component in high flux regions yet neither sampling technique biased the estimate of total degassing both diffuse soil fluxes up to 30 000 g m 2d 1 and emission rates from thermal vents up to 1 7 108 mol yr 1 were measured in thermal areas soil fluxes observed in most nonthermal regions were similar to values reported for conifer forests 15 g m 2 d 1 however through adaptive sampling high flux vegetated sites were identified in mud volcano that likely would not have been found if sampling was focused in obvious thermal or altered regions a simple model applied to flux measurements suggests that 40 of the analyzed measurements were dominated by possible advective transport and 30 by diffusive transport isotopic signatures of soil co2 generally suggest a deep origin 13c 2 3 to 0 0 in thermal areas and biogenic origin 13c 20 5 in nonthermal low flux areas vent emissions accounted for 32 63 of the total degassing observed at mud volcano 2 4 to 4 0 109 mol yr 1 the largest source of error in the estimation of total degassing factor of 2 resulted because the population distribution of thermal feature emissions was indeterminate total co2 emissions at mud volcano are comparable to other hydrothermal regions worldwide suggesting that the yellowstone volcanic system is likely a large contributor to global volcanic metamoohic hydrothermal vmh emissions

a multidisciplinary approach to detect active pathways for magma migration and eruption at mt etna sicily italy before the 2001 and 2002 2003 eruptions two strong flank eruptions occurred in july august 2001 and from late october 2002 to late january 2003 at mt etna volcano the two eruptions mainly involved the upper southern flank of the volcano a particularly active area during the last 30 years damaging several tourist facilities and threatening some villages the composite eruptive activity on the upper southern flank of mt etna during 2001 2003 has confirmed a posteriori the results of a multidisciplinary study started well before its occurrence by combining geological seismic and geochemical data gathered in this part of the volcano we were able in fact to highlight fractured zones likely to be re activated in the near future in this area where the largest majority of eruptive fissures in the recent past opened along n120 to n180 ranging directions the spatial distribution of earthquake epicentres during the period june 30th 2000 june 30th 2001 showed the greatest frequency in a sector compatible with both the direction of the main fissures of the pre 2001 period and that of the 2001 and 2002 lateral eruptions soil co2 and soil temperature surveys carried out in the studied area during the last 3 years have revealed anomalous release of magmatic fluids mainly co2 and water vapour along some nnw sse trending volcano tectonic structures of the area even during inter eruptive periods indicating persistent convective hydrothermal systems at shallow depth connected with the main feeder conduits of etna the temporal changes in both seismic and geochemical data from june 30th 2000 to june 30th 2001 were compared with the evolution of volcanic activity the comparison allowed to recognize at least two sequences of anomalous signals august to december 2000 and april to june 2001 likely related to episodes of step like magma ascent towards the surface as indicated by the following eruptive episodes the n120 to n180 structural directions are in accord with one of the main structural lines affecting eastern sicily they would be important pathways for magma uprise to the surface that will keep on feeding the eruptive activity of etna in the near future this study also pointed out the high instability of the southern slope of etna a sector where the potential hazard by lava flow invasion will remain high also in the near future

temporal variability of major and trace element concentrations in the groundwaters of mt etna italy effects of transient input of magmatic fluids highlighted by means of cluster analysis data for major minor and trace elements in groundwaters from mt etna volcano collected in 1994 1995 and 1997 were analyzed using cluster analysis ca two groups of sampling sites were identified named clusters a and b mainly on the basis of their different salinity and content of dissolved co2 the highest levels of both of these parameters were observed in the sites of cluster a located in the lower southwestern and central eastern flanks of the volcano for both of the statistical groups ca was repeated taking into account the mean values of each parameter in time and the results allowed us to recognize four distinct groups of parameters for each group of sites on the basis of their temporal patterns four different types of temporal patterns were recognized concave convex increasing decreasing the observed changes were basically interpreted as a result of the different response of dissolved chemical elements to changes in the aqueous environment and or in their solubility mobility in water due to different rates of input of magmatic gases to etna s aquifers the main changes occurred in 1995 when etna s volcanic activity resumed after a two year period of rest the temporal changes of the majority of the studied parameters water temperature water conductivity eh ph al mg b ca cl hg mn mo na ni se si sr cr zn and pco2 were not cluster dependent therefore they were not apparently affected by differences in water salinity between the two groups of sampling sites a limited number of parameters ti k li hco 3 as fe so 4 2 cu and v however manifested different behaviors depending on the cluster of sites to which they belonged thus suggesting their apparent dependency on water salinity

diffuse emission of carbon dioxide methane and helium 3 from teide volcano tenerife canary islands diffuse emission of co2 ch4 and he was investigated in the summit crater of teide volcano tenerife canary islands the results indicate that teide volcano releases abundant co2 not only from its active crater but also from its flanks as diffuse soil emanations the spatial distribution of these emanations correlates quite closely with that of geothermal anomalies and manifestations our flux measurements indicate a total output of 380 ton day 1 of co2 and 1 6 on day 1 of ch4 by diffuse degassing from the he co2 ratios and the co2 flux we estimate a diffuse he flux of 0 052 mol year 1 isotopic analysis of carbon in soil gas samples from sites of high soil co2 flux indicates a magmatic origin for the co2 also reported by high he 4he ratios of 5 50 and 5 87 ra the origin of methane is more uncertain with low 13c values suggesting a biogenic contribution

new perspectives on volcano monitoring in a tropical environment continuous measurements of soil co2 flux at piton de la fournaise la reunion island france detecting renewal of volcanic activity is a challenging task and even more difficult in tropical settings continuous measurements of soil co2 flux were carried out at the piton de la fournaise volcano during 2013 2016 since this site is in the tropics periods of heavy rainfall are in the norm measurements covered volcanic unrest after a hiatus of 3 5 years we find that while temperature has the strongest effect extreme rainfall causes short term noise when corrected and filtered from the environmental influence soil co2 time series permit to detect a major deep magmatic event during march april 2014 three months before the first eruption of the new activity phase correlation with geophysical datasets allow timing of further stages of upward fluid ascent our study validates soil co2 flux monitoring in tropical environments as a valuable tool to monitor magma transfer and to enhance understanding of volcano unrest down to the lithospheric mantle

chemical and isotopic characterization of the gases of mount etna italy abstract in the period 1990 1995 43 samples of dissolved gases in groundwaters wells springs and drainage galleries and 64 samples of free gases fumaroles bubbling and soil gases from the mount etna area were collected and analysed isotopic analyses were also carried out of both the carbon of the co 2 in free gases and dissolved inorganic carbon dic in the waters the chemical composition of the gases depends on the relative abundances of three interacting components these are gases of 1 atmospheric origin enriched in o 2 and n 2 present almost exclusively in dissolved gases 2 deep origin enriched in co 2 prevalent in the majority of cases and 3 more superficial origin enriched in ch 4 prevailing in peripheral areas the isotopic composition of co 2 carbon confirms its mantle origin with either thermometamorphic co 2 contributions or modifications due to interaction with hot waters

statistical analysis reveals spatial and temporal anomalies of soil co2 efflux on mount etna volcano italy abstract extensive geochemical surveys were carried out on the western flank of mt etna volcano for the determination of soil co 2 effluxes in order to study the relationship between soil gas anomalies faults and volcanic activity the areas of santa maria di licodia sml and w rift wr were selected because of their importance within the volcano tectonic framework of etna two gas surveys were performed in each area in different periods november 2005 and may 2006 in sml september 2007 and june 2008 in wr with 2140 measurements in total in each survey data were log normally distributed and were statistically different from the other surveys therefore their standard normal form was used to compare them log probability plots revealed five populations of data in each survey due to varying degrees of mixing between biogenic and magmatic co 2 and indicated anomalous co 2 effluxes for values 36 g m 2 d 1 magmatic output was 39 2 t d 1 in november 2005 15 8 t d 1 in may 2006 98 4 t d 1 in september 2007 and 234 1 t d 1 in june 2008 natural neighbor interpolation of standardized data produced distribution maps that showed some clustering of anomalous values along directions possibly related to hidden faults compatible with volcanic or regional structural trends analysis of magmatic co 2 emissions in time suggested a possible influence from seasonal variations but comparison with volcanic activity of etna also indicated a volcanic influence accompanying the 2008 2009 flank eruption

helium emission at cumbre vieja volcano la palma canary islands abstract we report herein the results of three soil helium surveys undertaken at cumbre vieja volcano la palma island canary islands helium content analyses at the surface environment of the volcano were carried out in the summers of 2002 2003 and 2004 to estimate the diffusion contribution of helium emission soil porosity was estimated indirectly from the granulometry data measured on a previous soil survey carried out in 1997 helium enrichments in the soil layer with respect to the air concentration measured on cumbre vieja indicate a strong structural control in the degassing processes of the volcano and the excess helium seems to be emitted mainly along both n s and n w rifts of the volcano 4 he flux values calculated following a pure diffusive model ranged between non detectable values and 1 0 mg m 2 d 1 in 2002 2003 and 2004 surveys total 4 he emission rate at cumbre vieja was estimated in the range of 18 38 kg d 1 isotopic composition of helium measured in soil gases along the n s volcanic rift of cumbre vieja showed small contributions of morb type helium increasing towards the southern part of the volcano a 3 he 4 he ratio of 9 95 0 12 r a was measured at a cold spring geothermal sample showing a 7 2 contribution of plume type helium 3 he emission results in the range of 0 6 0 7 mol yr support the hypothesis of contemporary degassing at cumbre vieja coming from magmas stored at different depths under la palma island

geochemical surveillance of the solfatara of pozzuoli phlegraean fields during 1983 geochemical surveillance of the phlegraean fields area has been intensified since 1983 in response to the increased uplift rate brady seismic activity fumarolic gases from solfatara pozzuoli were sampled and analyzed monthly a reducing capacity rc monitoring unit was installed at soffione the most active fumarole in the solfatara system the preliminary analysis of the rc temporal variations suggest they are consistent with the rate of the seismic energy release the composition of fumarolic gases indicates that the equilibrium temperature and pressure are higher than those of sampling the observed variations in ch4 content are explained as an increase of pressure from 1982 to the end of 1983 of about 70 at an extimated depth of 3 3 5 km finally during 1983 there were no geochemical indications of both rising magma and significant accumulation of energy at shallow depth

long term record of co2 degassing along mt etna s flanks and its relationship with magma dynamics and eastern flank instability a record of soil co2 flux data on the lower flanks of mt etna measured from 1989 to 2008 is discussed in the framework of multidisciplinary observations including seismicity ground deformations and flank instability a huge increase in soil co2 fluxes appears to be related to the dynamics of magma ascent in the upper portions of the volcano 0 3 km and the intrusion of dykes along the southern rift as mainly observed before the 1991 93 eruption even after the 1991 93 eruption the recharge of the shallow central reservoir was accompanied by a long term increase in soil co2 degassing mainly in the southwestern area the 2001 eruption marked dramatic changes in the areal distribution of seismicity the deformation pattern and the soil co2 degassing indeed while the soil co2 degassing showed background values in the southwestern area it progressively increased in the eastern sector and along the pernicana fault this has been related to the marked sliding of the eastern flank since the 2002 03 eruption and the associated seismicity this study provides evidence that the extent of soil co2 degassing on the lower flanks of mt etna is controlled by 1 the volume of involved magma 2 the intrusion of dykes in the upper parts of the volcano and 3 fault movement and seismicity this implies that different degassing structures must be monitored simultaneously when attempting to understand the behavior of the volcano as a whole

origin of hydrogen and carbon dioxide in fault gases and its relation to fault activity gases occluded in fracture zones of active faults are characterized by a high concentration of h 2 and or co 2 a predominant gas species h 2 or co 2 is related to the lithofacies which the fault cuts carbon dioxide concentration in sediments fluctuates with temperature this evidence and sigma 13 c of co 2 about 20 suggests that co 2 originates from organic materials carbon dioxide with sigma 13 c of 5 to 17 in brecciated gneiss containing marble may have been produced by interaction between organically derived co 2 and the marble or alternatively may have been magmatically derived hydrogen usually occurs in sheared silicate rocks and its concentration fluctuates a great deal the concentration of h 2 from active faults associated with historical earthquakes usually amounts to as high as several percent in maximum whereas the concentration of h 2 from quaternary faults not associated with historical earthquakes is at most 1

continuous monitoring of hydrogen and carbon dioxide at mt etna article i nfo this study assessed the use of an h2 fuel cell as an h2 selective sensor for volcano monitoring the resolution repeatability and cross sensitivity of the sensor were investigated and evaluated under known laboratory conditions a tailor made device was developed and used for continuously monitoring h2 and co2 at mt etna throughout 2009 and 2010 the temporal variations of both parameters were strongly correlated with the evolution of the volcanic activity during the monitoring period in particular the co2 flux exhibited long term variations while h2 exhibited pulses immediately before the explosive activity that occurred at mt etna during 2010

atmospheric dispersion of volcanic co 2 at vulcano island abstract intensive carbon dioxide emanations occur throughout the island of vulcano aeolian archipelago north of sicily italy the main sources of co 2 on the island are the hot fumaroles 500 c of the northern ridge of the la fossa crater the fumaroles of the baia di levante and the emission areas spread out both on the slopes of the cone and in the nearby plain the carbon dioxide from the soil can be considered as being emitted at air temperature in this work co 2 concentrations in the air over the island are estimated by means of two numerical codes this paper takes advantage of the parallel knowledge gained from a previously written paper for so 2 emissions from the la fossa volcanic cone j volcanol geotherm res 75 1997 283 here the attention is focused on co 2 and on the roles the different co 2 sources play in the inhabited area of vulcano porto village in the model chain the wind flow is simulated using a 3d mesoscale meteorological model for complex terrain the simulations are performed for the most significant large scale wind conditions derived from a meteorological analysis of the region flow model outputs are then used by way of a lagrangian particle model to simulate the dispersion of the gas and to calculate the concentrations the space and time evolution of gas concentration is discussed for various sources and output rates simulations show that the contributions to the concentrations at the inhabited area of vulcano porto village of 1 the cone slopes and the la forgia vecchia emitting areas and 2 of the crater fumaroles are both negligible the main contribution comes from the soil emission at the volcano feet results agree well with field measurements indicating a sharp decrease in co 2 concentration downwind and nocturnal peaks of few hundred ppm in the areas emitting 10 3 cm 3 co 2 stp cm 2 s the approach shows the absence of any risk to population at the present emission rates

cluster analysis of soil co2 data from mt etna italy reveals volcanic influences on temporal and spatial patterns of degassing soil co2 concentration data were collected periodically from july 2001 to june 2005 from sampling site grids in two areas located on the lower flanks of mt etna volcano paterno and zafferana etnea santa venerina cluster analysis was performed on the acquired data in order to identify possible groups of sites where soil degassing could be fed by different sources in both areas three clusters were recognised whose average co2 concentration values throughout the whole study period remained significantly different from one another the clusters with the lowest co2 concentrations showed time averaged values ranging from 980 to 1 170 ppm vol whereas those with intermediate co2 concentrations showed time averaged values ranging from 1 400 to 2 320 ppm vol and those with the highest concentrations showed time averaged values between 1 960 and 55 430 ppm vol we attribute the lowest co2 concentrations largely to a biogenic source of co2 conversely the highest co2 concentrations are attributed to a magmatic source whereas the intermediate values are due to a variable mixing of the two sources described above the spatial distribution of the co2 values related to the magmatic source define a clear direction of anomalous degassing in the zafferana etnea santa venerina area which we attribute to the presence of a hidden fault whereas in the paterno area no such oriented anomalies were observed probably because of the lower permeability of local soil time series analysis shows that most of the variations observed in the soil co2 data from both areas were related to changes in the volcanic activity of mt etna seasonal influences were only observed in the time patterns of the clusters characterised by low co2 concentrations and no significant interdependence was found between soil co2 concentrations and meteorological parameters the largest observed temporal anomalies are interpreted as release of co2 from magma batches that migrated from deeper to shallower portions of etna s feeder system the pattern of occurrence of such episodes of anomalous gas release during the observation period was quite different between the two studied areas this pattern highlighted an evident change in the mechanism of magma transport and storage within the volcano s feeder system after june 2003 interpreted as magma accumulation into a shallow 8 km depth reservoir

symmetric and asymmetric structures of hurricane boundary layer in coupled atmosphere wave ocean models and observations abstractit is widely accepted that air sea interaction is one of the key factors in controlling tropical cyclone tc intensity however the physical mechanisms for connecting the upper ocean and air sea interface with storm structure through the atmospheric boundary layer in tcs are not well understood this study investigates the air sea coupling processes using a fully coupled atmosphere wave ocean model especially the coupling induced asymmetry in surface winds sea surface temperature air sea fluxes and their impacts on the structure of the hurricane boundary layer hbl numerical experiments of hurricane frances 2004 with and without coupling to an ocean model and or a surface wave model are used to examine the impacts of the ocean and wave coupling respectively model results are compared with the airborne dropsonde and surface wind measurements on board the noaa wp 3d aircraft the atmosphere ocean coupling reduces the mixed layer depth in the rear right quadrant due to storm induced ocean

degassing of so2 and co2 at mount etna sicily as an indicator of pre eruptive ascent and shallow emplacement of magma abstract we studied soil co 2 emissions together with crater so 2 fluxes from mt etna during the period july 1997 to march 1999 this period was characterized by high levels of volcanic activity and ended with the onset of a 10 month long sub terminal eruption on february 4 1999 soil co 2 degassing was measured at two sites p39 on the lower sw flank of etna and p78 on the e flank known for being connected to deep faults that allow the escape of magmatic gas site p39 is inferred to drain gas from a deep 15 km magma reservoir whereas site p78 is connected to a shallower 5 10 km reservoir based on the temporal variations of measured soil co 2 and crater so 2 data five intervals of anomalous degassing were recognized each of them is interpreted as due to massive gas release from a magma batch that is moving toward the surface the time lag between the occurrence of degassing anomalies of co 2 and those of so 2 agrees well with the different depth of exsolution of the two gases our data also indicate a step like migration of magma to the surface which bears on the existence of at least three different temporary storage levels within etna s feeder system lastly the observed anomalies preceded by months to weeks increases in the summit activity of mt etna including the february 4 1999 eruption comparison between the amounts of degassing magma during each interval of anomalous degassing based on so 2 fluxes and erupted volumes of lava during the same periods seems to indicate that the 1999 eruption was largely fed by magma that started entering the upper feeder system of etna about 1 year earlier

measurements of 220rn and 222rn and co2 emissions in soil and fumarole gases on mt etna volcano italy implications for gas transport and shallow ground fracture this work was funded by the istituto nazionale di geofisica e vulcanologia s g m n and by the dipartimento per la protezione civile italy projects v3 6 28 etna m n and v5 08 diffuse degassing in italy s g and nsf ear 063824101 k w w s

investigating the deepest part of a volcano plumbing system evidence for an active magma path below the western flank of piton de la fournaise la reunion island abstract peripheral diffuse degassing of co 2 from the soil occurs across the western flank of piton de la fournaise volcano la reunion island indian ocean along a narrow zone in this area carbon isotopic analysis on soil gas samples highlights significant mixing between magmatic and organic end members the zones with the strongest magmatic signature highest 13 c overlap spatial distribution of hypocenters recorded shortly before and during volcano reactivation and allow discriminating a n135 degassing lineament with a minimum length of 11 km and 140 20 m width such orientation is in accordance with that of an old dyke network along the rift zone and with n120 130 and n140 155 lineaments related to the inheritance of oceanic lithosphere structures our findings show that this n135 lineament represents a preferential magmatic pathway for deep magma transfer below the volcano flank moreover spatial distributions of recent eccentric cones indicate a well founded possibility that future eruptions may by pass the shallow plumbing system of the central area of the volcano taking a lateral pathway along this structure our results also confirm that piton de la fournaise activity is linked to a laterally shifted plumbing system and represent a major improvement in identifying the main high risk area on the densely populated western flank of the volcano

focused and diffuse effluxes of co2 from mud volcanoes and mofettes south of mt etna italy abstract several sites with anomalous emissions of carbon dioxide were investigated in the region south of mt etna volcano in order to assess the types of emission focused and or diffuse their surface extension and the total output of co 2 most of the studied emissions are located on the southwest boundary of mt etna near the town of paterno they consist of three mud volcanoes known as salinelle one spring with bubbling gas acqua grassa and one area of diffuse degassing pescheria another site naftia lake with remarkable gas emissions bubbling gas into a lake as well as adjacent areas of diffuse soil degassing is located further southwest of mt etna in an area of extinct quaternary volcanism on the northwest margin of hyblean mts in all of these areas the origin of the highest co 2 emissions is clearly magmatic and degassing to the atmosphere occurs mostly through tectonic structures probably at a regional scale the magmatic source that feeds anomalous degassing in the above areas is likely to be the same that feeds volcanic activity at mt etna focused degassing was measured at each emission vent using devices that measure the air speed whereas diffuse soil degassing was measured using the accumulation chamber method in total 712 measurements were carried out 146 in focused degassing vents 566 on diffuse degassing areas single co 2 output values ranged from 1 8 10 5 to 1 68 kg s 1 in the case of diffuse degassing areas statistical analyses allowed to discriminate between biogenic co 2 and co 2 deriving from a magmatic hydrothermal source only the efflux values from the latter source were considered in the output estimates the total estimated output thus obtained was about 2 61 kg s 1 relevant to a total surface of about 146 500 m 2 which includes only the magmatic co 2 emissions this value is comparable with that of most non volcanic emissions from geothermal and or faulted areas of central southern italy as well with the co 2 output from some of the volcanic areas of italy

diffuse surface emanations as indicator of structural permeability in fault controlled geothermal systems abstract diffuse degassing processes provide valuable information on geothermal reservoir characteristics not only in the context of monitoring but also for exploration purposes areas with increased gas emissions can be indicative of major upflow zones from the reservoir through deep reaching permeable fault zones these fault zones may act as preferential target areas for geothermal production drillings in this study it is successfully demonstrated that diffuse degassing measurements can be used for the detection and characterization of permeable structural elements the combination of following techniques has been applied at the brady s geothermal system in the basin and range province nevada usa accumulation chamber method for carbon dioxide and hydrogen sulfide measurements alpha spectroscopic measurements of radon and thoron activity concentrations and gamma spectroscopic measurements of selected nuclides

soil co2 degassing on mt etna sicily during the period 1989 1993 discrimination between climatic and volcanic influences wide variations were measured in the diffuse co2 flux through the soils in three selected areas of mt etna between august 1989 and march 1993 degassing of co2 from the area of zafferana etnea s venerina on the eastern slope of the volcano has been determined to be more strongly influenced by meteorological parameters than the other areas the seasonal component found in the data from this area has been excluded using a filtering algorithm based on the best fitting equation calculated from the correlation between co2 flux values and those of air temperature the filtered data appear to have variations temporally coincident with those from the other areas thus suggesting a common and probably deep source of gas the highest fluxes measured in the two most peripheral areas may correlate well with other geophysical and volcanological anomalous signals that preceded the strong eruption of 1991 1993 and that were interpreted as deep pressure increases anomalous decreases in co2 fluxes accompanied the onset and the evolution of that eruption and have been interpreted as a sign of upward migration of the gas source the variations of co2 flux at the 1989 se fracture have also given interesting information on the timing of the magmatic intrusion that has then fed the 1991 1993 eruption

eddy covariance imaging of diffuse volcanic co2 emissions at mammoth mountain ca usa use of eddy covariance ec techniques to map the spatial distribution of diffuse volcanic co2 fluxes and quantify co2 emission rate was tested at the horseshoe lake tree kill area on mammoth mountain california usa ec measurements of co2 flux were made during september october 2010 and ranged from 85 to 1 766 g m 2 day 1 comparative maps of soil co2 flux were simulated and co2 emission rates estimated from three accumulation chamber ac co2 flux surveys least squares inversion of measured eddy covariance co2 fluxes and corresponding modeled source weight functions recovered 58 77 of the co2 emission rates estimated based on simulated ac soil co2 fluxes spatial distributions of modeled surface co2 fluxes based on ec and ac observations showed moderate to good correspondence r2 0 36 to 0 70 results provide a framework for automated monitoring of volcanic co2 emissions over relatively large areas

grain size geochemistry and organic pollutants in modern fluvial deposits in eastern moravia czech republic modern fluvial deposits from both small and large rivers were studied at 14 monitoring sites over 2 years 4 successive sampling seasons in the area of eastern moravia czech republic grain size geochemistry content of persistent organic pollutants pahs pcbs hchs ddts hcbs and pecb and toc were examined with the aim to understand their mutual relations and seasonal variations in sediment character and pollutant content sand and silt fraction predominate and the clay content is relatively low differences in provenance for various river systems were recognised both regional and seasonal variations in terms of content of persistent organic pollutants were documented the content of toc and mud was shown to play an important role in the accumulation of chlorinated persistent organic pollutants pcbs hchs ddts and hcb

monitoring of fumarole discharge during the 1975 1982 rifting in krafla volcanic center north iceland abstract fumarole discharge chemistry in the krafla geothermal field changed regionally during the 1975 1982 rifting activity the discharge chemistry previously encountered in the krafla fumarole grounds was masked by a carbon dioxide rich gas during the first weeks of rifting the new discharge composition remained unchanged until 1983 when the first signs of recovery of the previous equilibrium composition appeared at the margins of the area the outgassing carbon dioxide is released from the deep aquifers beneath the area by the interaction of magmatic gas with the hydrothermal system in addition to juvenile magmatic carbon the outgassing contains carbon released from the hydrothermal systed upon reaction with acid magmatic gases increased boiling of the hydrothermal fumaroles was induced by the lowering of the partial pressure of steam due to increased gas content in the fumarole conduits at the center of rifting activity above the magma chamber the fumarole discharge was temporarily mixed with magmatic gases during local effusive activity hydrogen was the dominating magmatic gas in that discharge due to the preferred degassing of hydrogen from magma at shallow levels these hydrogen pulses increased in magnitude and duration towards the end of rifting in 1982 the discharge chemistry correlates with the expansion of the magma reservoir of the volcano regional change of long duration and local volcanism short lived change hydrogen pulses the chemical monitoring of fumaroles in krafla shows that the chemical surveillance of volcanos needs rapid methods for sampling and complete chemical analysis which can be interpreted in terms of reactions and magmatic processes

geochemical monitoring system ii prototype gms ii installation at the acqua difesa well within the etna region first data during the 1999 volcanic crisis abstract the geochemical monitoring system ii gms ii prototype was designed assembled tested and installed at the acqua difesa test site near belpasso ct within the etna region in the frame of an ec funded program named automatic geochemical monitoring of volcanoes the easily changeable and versatile configuration of the remote station provides actual data every 10 min recording groundwater temperature electrical conductivity ph redox potential dissolved co 2 he atmospheric pressure and air temperature the radon sensor was assembled despite no jet added to the remote station an automatic sampler collects every 72 h 3 days two bottles of water acidified and not for further laboratory analyses the choice of the acqua difesa test site arises from preliminary volcanological studies deserving special interest i e for the high co 2 degassing for the high he isotopic values exhibiting a direct mantle signature of the volcanic gases and for the peculiar sensitivity to volcanic activity as tested by discrete monitoring in the past and confirmed by the present study during the discussed monitoring period october 1998 june 1999 an enhanced volcanic activity of etna was observed it started on july 1998 with enhanced plume degassing and since september 1998 with periodical lava fountains as well as with episodic low energy earthquakes and seismic swarms m max 3 1 till june 1999 the activity culminated with a summit crater fracture involving a sub terminal eruption on 04 02 1999 the summit crater fracture was not accompanied by enhanced seismicity despite moderate seismic energy release occurring in the succeeding months in that monitoring period the acqua difesa gms ii station recorded a few geochemical anomalies mostly in temperature ph co 2 electrical conductivity and eh as well as in the concentration of some major elements trend mostly in mg and hco 3 the geochemical continuous and discrete data set is discussed in comparison with the available information on the ongoing volcanic and seismic activity tentatively enhancing the comprehension of the aquifers mass heat transport properties of the volcano during crises the experimental observations may be defined at present the forerunners of the etna eruptions affecting the single out acqua difesa well it is nowadays a self consistent site with its own response to the pre eruptive processes defined sensitive to the etna aquifer modifications induced by the volcanic activity in a recurrent way thus we defined the typical answer of this specific test site to the pre eruptive processes and to the associated seismicity further data may modify this statement the station prototype configuration and the results may give hints for future volcanic eruption and seismic activity forecasting