carbon dioxide discharged through the las canadas aquifer tenerife canary islands carbon dioxide is one of the first gases to escape the magmatic environment due to its low solubility in basaltic magmas at low pressures the exsolved co2 gas migrates towards the surface through rock fractures and high permeability paths if an aquifer is located between the magmatic environment and the surface a fraction of the co2 emitted is dissolved in the aquifer in this paper an estimation of the water mass balance and the co2 budget in las canadas aquifer tenerife canary islands is presented magmatic co2 is transported by groundwater and discharged through man made sub horizontal drains or galleries that exist in this island and by the flow of groundwater discharged laterally towards other aquifers or to the ocean in addition the pco2 at the gallery mouth or entrance and at the gallery bottom internal and deepest discharge point where the gallery starts are calculated and mapped the total co2 advectively transported by groundwater is estimated to range from 143 to 211 t co2 d 1 considering that the diffuse soil emission of co2 for the same area is 437 t d 1 the diffuse dissolved co2 flux ratio varies between 2 and 3 the high dissolved inorganic carbon content of groundwater explains the ability of this low temperature hydrothermal water to dissolve and transfer magmatic co2 at volcanoes even during quiescence periods

total co2 output from vulcano island aeolian islands italy 1 total co2 output from fumaroles soil gas bubbling gas discharges and water dissolved gases discharged from the island was estimated for vulcano island italy the co2 emission from fumaroles from the la fossa summit crater was estimated from the so2 crater output while co2 discharged through diffuse soil emission was quantified on the basis of 730 measurements of co2 fluxes from the soil of the island performed by using the accumulation chamber method the results indicate an overall output of 500 t day 1 of co2 from the island the main contribution to the total co2 output comes from the summit area of the la fossa cone 453 t day 1 with 362 t day 1 from crater fumaroles and 91 t day 1 from crater soil degassing the release of co2 from peripheral areas is 20 t day 1 by soil degassing palizzi and istmo areas mainly an amount comparable to both the contribution of water dissolved co2 6 t day 1 as well as to seawater bubbling co2 4 t day 1 measured in the istmo area presented data september 2007 refer to a period of moderate solphataric activity when the fumaroles temperature were 450 c and gas water molar ratio of fumaroles was up to 0 16 the calculated total co2emission allows the estimation of the mass release and related thermal energy from the volcanic hydrothermal system

deep co2 emitted at furnas do enxofre geothermal area terceira island azores archipelago an approach for determining co2 sources and total emissions using carbon isotopic data abstract quantification of the co2 released by the volcanoes to the atmosphere is relevant for the evaluation of the balance between deep derived biogenic and anthropogenic contributions the current study estimates the co2 released from furnas do enxofre degassing area terceira island azores archipelago by applying an approach that integrates the flux of co2 from the soil with the 13c co2 values a deep derived co2 output of 2 54 t d 1 is estimated for an area of 23 715 m2 high biogenic derived co2 flux values 45 g m 2 d 1 associated with light carbon isotopic content 13c 28 1 1 are detected and explained by the type of vegetation that characterizes the study site carbon isotopic compositions of the co2 6 4 1 2 measured in olivine hosted fluid inclusions of the terceira basalts are presented for the first time and contribute to defining the mantle co2 signature differences between these values and heavier carbon isotope values from gas in fumaroles at furnas do enxofre 4 66 to 4 27 are explained by the carbon isotopic fractionation occurring when co2 reacts to form calcite in the geothermal reservoir at temperatures 180 c a clear correlation between the soil temperature and deep co2 fluxes is observed and the integration of the diffuse degassing information with the composition of the fumarolic emissions allows estimating a thermal energy flux of 1 1 mw

effect of the volcanic front migration on helium nitrogen argon and carbon geochemistry of hydrothermal magmatic fluids from hokkaido volcanoes japan abstract active volcanoes from hokkaido are distributed along the sw ne trending volcanic front where the subducting pacific plate changes direction from n s to wsw ese one exception is the tokachi volcano which is located approximately 50 km to the north west of the current volcanic front the tokachi oki slab cracking zone represents the transitional zone between the honshu and kurile trenches this change is responsible for the rapid lateral variation of the subduction angle and slab shape we investigate the consequence of this change on the chemical and isotopic compositions from hydrothermal magmatic fluids and mineral separates collected from three volcanoes of hokkaido northern japan namely tarumae tokachi and meakan our data show that these volcanoes have a distinct range of he n and c isotopic compositions meakan fumaroles have a 3he 4he ratio that ranges from 4 46ra to 6 88ra 15n from 2 2 to 3 5 and 13c co2 from 8 47 to 9 81 consistent with subducted sediment contribution tarumae fumaroles have a particularly low 3he 4he ratio 3 08ra in comparison with their hot springs up to 5 24ra and are associated with high co2 3he ratios 2 2 5 3 1011 hydrothermal crustal interactions from the dome or from a deeper hydrothermal system are the main mechanisms that control the 3he 4he and co2 3he ratios in tarumae fumaroles the 15n and 13c co2 values for tarumae volcano range from 0 6 to 3 1 and from 6 34 to 6 43 respectively tokachi fumaroles are characterized by high 3he 4he up to 7 38ra low 15n 2 4 0 1 and low 13c co2 up to 5 32 consistent with mantle contribution and minor subducted sediment contribution the limestone sediment mantle ratio shows a decreasing contribution from subducted sediments starting from tokachi 1 9 to meakan 3 4 and finally tarumae 5 3 this change of isotopic compositions from the sw ne of hokkaido is the result of the tokachi oki slab cracking zone slab dehydration under tokachi occurs at a deeper level 150 200 km than in other hokkaido volcanoes 100 km which produces the migration of the volcanic front therefore we argue that the isotopic signature of tokachi is the result of i a lower sediment contribution from the slab ii a deeper dehydration of the slab and iii a lower degree of partial melting

gas emission from diffuse degassing structures dds of the cameroon volcanic line cvl implications for the prevention of co2 related hazards abstract in the mid 1980s lakes nyos and monoun violently released massive gas mainly magmatic co 2 killing about 1800 people subsequent geochemical surveys and social studies indicate that lakes nyos and monoun event is cyclic in nature and may occur anywhere in the about 37 other volcanic lakes located in the corridor of the cameroon volcanic line cvl this potential threat motivated us to check if alike nyos and monoun the internal dynamic of the other lakes is also controlled by inputs of deep seated derived co 2 and attempt to measure and provide comprehensive insights on the passive gas emission along the cvl this knowledge shall contribute to the prevention of volcanic lake related hazards in cameroon and the refinement of the global carbon cycle we used in situ fixation and dry gas phase sampling methods to determine co 2 origin and the concentration and the accumulation chamber technique to measure diffuse co 2 emission from nine lakes and on soil at nyos valley and mount manenguba caldera the results suggest that although in minor concentrations compared to nyos and monoun ranging from 0 56 mmol kg 1 to 8 75 mmol kg 1 the bottom waters of some lakes also contain measurable magmatic co 2 with 13 c varies from 4 42 to 9 16 vs pdb that finding implies that under certain circumstances e g increase to volcanic and or tectonic activities along the cvl the concerned lakes could develop a nyos type behavioural scheme the diffuse gas emission results indicate that the nine surveyed lakes release approximately 3 69 0 37 kt km 2 yr 1 of co 2 to the atmosphere extrapolation to the approximately 39 volcanic lakes located on the cvl yields an approximate co 2 output of 27 37 0 5 kt km 2 yr 1 representing 0 023 of the global co 2 output from volcanic lakes in addition to the precedent value the gas removal operation in lakes nyos and monoun released approximately 2 52 0 46 10 8 mol km 2 yr 1 co 2 to the atmosphere from january 2001 to march 2013 more than double the per area co 2 released by the yellowstone volcanic system the co 2 emission from soil was estimated to be 4 57 1 30 kt km 2 yr 1 the soil gas geochemistry of the mount manenguba caldera also indicates a dominant magma derived co 2 mean 13 c 8 6 vs vpdb

monitoring volcanic hazard using eddy covariance at solfatara volcano naples italy an eddy covariance ec station was deployed at solfatara crater italy june 8 25 2001 to assess if ec could reliably monitor co2 fluxes continuously at this site deployment at six different locations within the crater allowed areas of focused gas venting to be variably included in the measured flux turbulent ec fluxes calculated in 30 min averages varied between 950 and 4460 g co2 m 2 d 1 the highest measurements were made downwind of degassing pools comparing turbulent fluxes with chamber measurements of surface fluxes using footprint models in diffuse degassing regions yielded an average difference of 0 4 indicating that ec measurements are representative of surface fluxes at this volcanic site similar comparisons made downwind of degassing pools yielded emission rates from 12 to 27 t co2 d 1 for these features reliable ec measurements i e measurements with sufficient and stationary turbulence were obtained primarily during daytime hours 08 00 and 20 00 local time when the wind speed exceeded 2 m s 1 daily average ec fluxes varied by 50 and variations were likely correlated to changes in atmospheric pressure variations in co2 emissions due to volcanic processes at depth would have to be on the same order of magnitude as the measured diurnal variability in order to be useful in predicting volcanic hazard first order models of magma emplacement suggest that emissions could exceed this rate for reasonable assumptions of magma movement ec therefore provides a useful method of monitoring volcanic hazard at solfatara further ec can monitor significantly larger areas than can be monitored by previous methods

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

precursory diffuse carbon dioxide degassing signature related to a 5 1 magnitude earthquake in el salvador central america abstract anomalous changes in the diffuse emission of carbon dioxide have been observed before some of the aftershocks of the 13 february 2001 el salvador earthquake magnitude 6 6 a significant increase in soil co 2 efflux was detected 8 days before a 5 1 magnitude earthquake on 8 may 2001 25 km away from the observation site in addition pre and co seismic co 2 efflux variations have also been observed related to the onset of a seismic swarm beneath san vicente volcano on may 2001 strain changes and or fluid pressure fluctuations prior to earthquakes in the crust are hypothesized to be responsible for the observed variations in gas efflux at the surface environment of san vicente volcano

volatiles and energy released by purace volcano total co2 output of purace volcano colombia was estimated on the basis of fluids discharged by fumaroles soil gases and dissolved carbon species in the aquifer the soil co2 emission was computed from a field survey of 512 points of co2 soil flux measurements at the main degassing areas of purace volcano the co2 flux from purace s plume was estimated using an indirect method that used the so2 plume flux and co2 so2 ratio of the main high temperature fumarole the total output of co2 was estimated at 1500 t day the main contribution of co2 comes from the plume summit degassing and from soil degassing that emit 673 and 812 t day respectively the contributions of summit and soil degassing areas are comparable indicating an intermediate degassing style partitioned between closed and open conduit systems the estimated water vapor discharge as derived from the chemical composition of the fumaroles the h2o co2 ratio and the so2 plume flux allowed calculation of the total thermal energy fumarolic soil degassing and aquifer released from the purace volcanic system this was 360 mw

carbon dioxide emissions from soils at hakkoda north japan 1 a soil gas and co2 efflux survey was carried out at hakkoda north japan to investigate the spatial distribution and origin of the gas which caused the accidental death of three japanese soldiers on 12 july 1997 in the study area no fumarolic and or thermal activity is observed chemical composition of the gas from areas with high co2 effluxes 5 000 g m 2 d 1 and high co2 contents 15 vol indicate a strong deep sourced contribution for co2 whereas air and or air saturated water is suggested for the rest of the discharged gases which are mainly released from a shallow aquifer isotopic analysis of soil gas and hot spring discharges suggests a combination of magmatic degassing and thermal decarbonation with magmatic degassing being the main contributior to the high co2 emission approximately 74 t d 1 of deep seated magmatic plus thermal decarbonation origin co2 were estimated to contribute to the total output of co2 from this area

changes in the diffuse co2 emission and relation to seismic activity in and around el hierro canary islands significant changes in the diffuse emission of carbon dioxide were recorded in a geochemical station located at el hierro canary islands before the occurrence of several seismic events during 2004 two precursory co2 efflux increases started thirteen and nine days before two seismic events of magnitude 2 3 and 1 7 which took place near el hierro island canary islands on march 23 and april 15 reaching a maximun value of 51 1 and 46 2 g m 2 d 1 respectively five and eight days before the two seismic events other similar increases started thirteen and five days before the occurrence of two seismic events of magnitude 1 3 and 1 5 which took place on october 15 and 21 respectively reaching the maximum values four and one day before the earthquakes these changes were not related to variations in atmospheric or soil parameters the material failure forecast method ffm which analyzes the rate of precursory phenomena was successfully applied to forecast the first seismic event that took place in el hierro island in 2004

diffuse co2 emission rate from pululahua and the lake filled cuicocha calderas ecuador abstract we report herein the first results of two soil co 2 efflux surveys carried out at cuicocha lake filled and pululahua caldera volcanic systems ecuador a total of 172 and 217 soil co 2 efflux measurements were taken at the surface environment of pululahua and cuicocha calderas respectively by means of the accumulation chamber method during the summer of 2006 to constrain the total co 2 output from the studied area soil co 2 efflux values ranged from non detectable up to 48 5 and 141 7 g m 2 d 1 for cuicocha and pululahua calderas respectively in addition probability graphs were used to distinguish the existence of different geochemical populations sequential gaussian simulation was used to construct an average map for 100 simulations and to compute the total co 2 emission at each studied area 106 and 270 t d 1 metric tons per day for cuicocha 13 3 km 2 and pululahua 27 6 km 2 volcanoes respectively

precursory diffuse co2 and h2s emission signatures of the 2011 2012 el hierro submarine eruption canary islands 1 on october 12 2011 a submarine eruption began 2 km off the coast of la restinga south of el hierro island co2 and h2s soil efflux were continuously measured during the period of volcanic unrest by using the accumulation chamber method at two different geochemical stations hie01 and hie07 recorded co2 and h2s effluxes showed precursory signals that preceded the submarine eruption beginning in late august the co2 efflux time series started increasing at a relatively constant rate over one month reaching a maximum of 19 gm 2d 1 one week before the onset of the submarine volcanic eruption the h2s efflux time series at hie07 showed a pulse in h2s emission just one day before the initiation of the submarine eruption reaching peak values of 42 mg m 2 d 1 10 times the average h2s efflux recorded during the observation period since co2 and h2s effluxes are strongly influenced by external factors we applied a multiple regression analysis to remove their contribution a statistical analysis showed that the long term trend of the filtered data is well correlated with the seismic energy we find that these geochemical stations are important monitoring sites for evaluating the volcanic activity of el hierro and that they demonstrate the potential of applying continuous monitoring of soil co2 and h2s efflux to improve and optimize the detection of early warning signals of future volcanic unrest episodes at el hierro continuous diffuse degassing studies would likely prove useful for monitoring other volcanoes during unrest episodes

diffuse emission of carbon dioxide from cerro negro volcano nicaragua central america we report the first detailed soil co2 efflux survey carried out at cerro negro volcano nicaragua central america soil co2 efflux values ranged from 0 5 to 35 000 g m 2 d 1 spatial distribution of co2 efflux shows that volcanic gas is mainly released from the summit crater and the fissures opened during the august 1999 eruption the total co2 output of cerro negro is conservatively estimated to be 2 800 t d 1 based on a study area of 0 58 km contour maps of soil co2 efflux ground temperature and 13c co2 distributions support an important magmatic contribution for the total output of co2 at cerro negro volcano

three year decline of magmatic co2 emissions from soils of a mammoth mountain tree kill horseshoe lake ca 1995 1997 we used the closed chamber method to measure soil co2 efflux over a three year period at the horseshoe lake tree kill hltk the largest tree kill on mammoth mountain in central eastern california efflux contour maps show a significant decline in the areas and rates of co2 emission from 1995 to 1997 the emission rate fell from 350 t d 1 metric tons per day in 1995 to 130 t d 1 in 1997 the trend suggests a return to background soil co2 efflux levels by early to mid 1999 and may reflect exhaustion of co2 in a deep reservoir of accumulated gas and or mechanical closure or sealing of fault conduits transmitting gas to the surface however emissions rose to 220 t d 1 on 23 september 1997 at the onset of a degassing event that lasted until 5 december 1997 recent reservoir recharge and or extension enhanced gas flow may have caused the degassing event

geographical distribution of 3he 4he ratios in japan implications for arc tectonics and incipient magmatism the 3he 4he and 4he 20ne ratios of 115 natural gas samples including various types of gases from volcanoes hot springs mineral springs water wells petroleum fields and natural gas fields were measured using a mass spectrometer the observed 3he 4he and 4he 20ne ratios range from 7 47 10 8 to 9 65 10 6 and from 0 26 to 1100 respectively the 3he 4he ratios reflect well the geotectonic structure of the japanese islands in northeastern ne japan there is a clear geographical difference in the 3he 4he ratios between the frontal arc forearc and volcanic arc back arc regions lower ratios were found in the trench side region and higher ratios in the back arc side this result suggests that the mantle derived helium in the volcanic arc region is associated with the diapiric uprise of a magma lower 3he 4he ratios in the frontal arc region may be due to radiogenic he produced by radioactive decay of u and th in the crustal and sedimentary rocks in southwestern sw japan there is no clear geographical contrast in the 3he 4he ratios some samples in the frontal arc region show quite high 3he 4he ratios the tendency of the 3he 4he ratios agrees with the distribution of terrestrial heat flow data and reflects geotectonic structures different from ne japan the high 3he 4he ratios observed in the frontal arc region in sw japan may be indicative of renewed or incipient magmatism due to a descending young and warm slab

multivariate analysis of co2 h2s and ch4 diffuse degassing and correlation with fault systems in agua caliente tzitzio michoacan mexico abstract the quantitative relationships between soil gas flux anomalies and faults systems in agua caliente tzitzio geothermal system were analyzed statistically the main degassing features are related with thermal springs the data used in the multivariate analysis are geothermal gas fluxes and spatial structural data i e local fault strike exploratory data analysis eda and multivariate analysis of variance manova were implemented for the first time to statistically describe the relation between the location of degassing features and the presence of some local fault systems discriminating the direction of the main discharge channels and pointing to higher permeability faults the results show that there is a statistically significant correlation between diffuse degassing of co2 and ch4 and the n s and e w fault systems conversely h2s degassing does not show any correlation with the fault systems which may be related with the higher h2s reactivity compared with that of co2 and ch4 it is highly recommended to use eda and manova techniques in order to establish the main degassing directions in geothermal and volcanic areas

crater lake temperature changes of the 2005 eruption of santa ana volcano el salvador central america a sudden eruption at santa ana occurred on 1 october 2005 producing an ash and gas plume to a height in excess of 10 km above the volcano several days before thermal infrared images of the crater provided precursory signals of the eruption a significant increase in the extent and intensity of the fumarolic field inside the crater rim and of the surface temperature of the crater s lake was observed changes in energy input was also estimated to explain the increase in lake temperature based on energy mass balance calculations

six week time series of eddy covariance co2 flux at mammoth mountain california performance evaluation and role of meteorological forcing co sub 2 and heat fluxes were measured over a six week period 09 08 2006 to 10 24 2006 by the eddy covariance ec technique at the horseshoe lake tree kill hltk mammoth mountain ca a site with complex terrain and high spatially heterogeneous co sub 2 emission rates ec co sub 2 fluxes ranged from 218 to 3500 g m sup 2 d sup 1 mean 1346 g m sup 2 d sup 1 using footprint modeling ec co sub 2 fluxes were compared to co sub 2 fluxes measured by the chamber method on a grid repeatedly over a 10 day period half hour ec co sub 2 fluxes were moderately correlated r sup 2 0 42 with chamber fluxes whereas average daily ec co sub 2 fluxes were well correlated r sup 2 0 70 with chamber measurements average daily ec co sub 2 fluxes were correlated with both average daily wind speed and atmospheric pressure relationships were similar to those observed between chamber co sub 2 fluxes and the atmospheric parameters over a comparable time period energy balance closure was assessed by statistical regression of ec energy fluxes sensible and latent heat against available energy net radiation less soil heat flux while incomplete r sup 2 0 77 for 1 1 line the degree of energy balance closure fellmore within the range observed in many investigations conducted in contrasting ecosystems and climates results indicate that despite complexities presented by the hltk ec can be reliably used to monitor background variations in volcanic co sub 2 fluxes associated with meteorological forcing and presumably changes related to deeply derived processes such as volcanic activity less

diffuse emission of hydrogen from poas volcano costa rica america central we report the results of four soil h2 surveys carried out in 2000 2003 at poas volcano costa rica to investigate the soil h2 distribution and evaluate the diffuse h2 emission as a potential surveillance tool for poas volcano soil gas h2 contents showed a wide range of concentration from 0 2 to 7 059 ppmv during the four surveys maps of soil gas h2 based on sequential gaussian simulation showed low h2 concentration values in the soil atmosphere 0 7 ppmv for most of the study area whereas high soil gas h2 values were observed inside the active crater of poas a significant increase in soil gas h2 concentration was observed inside the active crater during 2001 and 2002 with respect to year 2000 followed by a decrease in 2003 the observed spatial and temporal variations of soil h2 concentration have been well correlated with seismicity microgravimetry and fumarolic chemistry changes which occurred during this study these observations evidence changes in the shallow magmatic hydrothermal system of poas and it might be related to a potential magmatic intrusion during the period 1998 2004 therefore monitoring diffuse h2 emission of poas has become an important geochemical tool for the monitoring of its volcanic activity

anomalous diffuse co2 emission prior to the january 2002 short term unrest at san miguel volcano el salvador central america on january 16 2002 short term unrest occurred at san miguel volcano a gas and steamash plume rose a few hundred meters above the summit crater an anomalous microseismicity pattern about 75 events between 7 30 and 10 30 hours was also observed continuous monitoring of co2 efflux on the volcano started on november 24 2001 in the attempt to provide a multidisciplinary approach for its volcanic surveillance the background mean of the diffuse co2 emission is about 16 g m 2 d 1 but a 17 fold increase up to 270 g m 2 d 1 was detected on january 7 nine days before the january 2002 short term unrest at san miguel volcano these observed anomalous changes on diffuse co2 degassing could be related to either a sharp increase of co2 pressure within the volcanic hydrothermal system or degassing from an uprising fresh gas rich magma within the shallow plumbing system of the volcano since meteorological fluctuations cannot explain this observed increase of diffuse co2 emission

geochemical evidence of magma intrusion inferred from diffuse co 2 emissions and fumarole plume chemistry the 2010 2011 volcanic unrest at taal volcano philippines we report herein significant increases in the diffuse co2 emission through the lake and soils of the taal volcano main crater philippines during a volcano seismic unrest period in april 2010 june 2011 monitoring of co2 emissions from the taal main crater lake and soils in the fumarole areas started in 2008 with a collaborative project between iter and phivolcs in august 2010 the total diffuse co2 emission from the taal main crater lake increased almost three times from a previously measured baseline emission value 1 000 t day 1 to 2 716 54 t day 1 this increase occurred during anomalous seismic activity which started in april 2010 the highest co2 emission value in the crater lake was measured in march 2011 at 4 670 159 t day 1 when the volcano was still showing signs of unrest significant changes in the co2 so2 co2 h2o and so2 h2s ratios in the fumarole gases suggest the occurrence of a magmatic injection several weeks before the onset of the volcano seismic unrest period these observed changes in the co2 emission rate and the fumarole gas composition as the result of magmatic activity were likely caused by magma moving from a deep reservoir to a shallow reservoir

flux measurements of explosive degassing using a yearlong hydroacoustic record at an erupting submarine volcano at nw rota 1 are primarily h2o so2 and co2 instantaneous fluxes varied by a factor of 100 over the deployment using melt inclusion information to estimate the concentration of co2 in the explosive gases as 6 9 0 7 wt we calculate an annual co2 eruption flux of 0 4 0 1 tg a 1 this result is within the range of measured co2 fluxes at continuously erupting subaerial volcanoes and represents 0 2 0 6 of the annual estimated output of co2 from all subaerial arc volcanoes and 0 4 0 6 of the mid ocean ridge flux the multiyear eruptive history of nw rota 1 demonstrates that submarine volcanoes can be significant and sustained sources of co2 to the shallow ocean

monitoring quiescent volcanoes by diffuse co2 degassing case study of mt fuji japan since the 8th century more than seventeen eruptions have been recorded for the mt fuji volcano with the most recent eruption occurring in 1707 hoei eruption for the past 300 years the volcano has been in a quiescent stage and since the early 1960s has exhibited neither fumarolic nor thermal activity however the number of low frequency earthquakes with a hypocentral depth of 10 20 km increased significantly beneath the northeastern flank of mt fuji in 2000 2001 suggesting a possible resumption of magmatic activity in this study diffuse co2 efflux and thermal surveys were carried out in four areas of the volcano in 2001 2002 in order to detect possible signs of the upward movement of deep magma at all survey points the co2 efflux was below the detection limit with the exception of a few points with biological co2 emission and ground temperatures at a depth of 20 30 cm were below ambient indicating no surface manifestations of gas or heat emission should magma rise into the subsurface the diffuse co2 efflux would be expected to increase particularly along the tectonically weakened lineation on the mt fuji volcano allowing for the early detection of pre eruptive degassing

fumarole plume and diffuse co 2 emission from sierra negra caldera galapagos archipelago measurements of visible and diffuse gas emission were conducted in 2006 at the summit of sierra negra volcano galapagos with the aim to better characterize degassing after the 2005 eruption a total so2 emission of 11 2 t day 1 was derived from miniature differential optical absorption spectrometer mini doas ground based measurements of the plume emanating from the mini azufral fumarolic area the most important site of visible degassing at sierra negra volcano using a portable multigas system the h2s so2 co2 so2 and h2o so2 molar ratios in the mina azufral plume emissions were found to be 0 41 52 2 and 867 9 respectively the corresponding h2o co2 and h2s emission rates were 562 394 and 3 t day 1 respectively the total output of diffuse co2 emissions from the summit of sierra negra volcano was 990 85 t day 1 with 605 t day 1 being released by a deep source the diffuse to plume co2 emission ratio was about 1 5 mina azufral fumaroles released gasses containing 73 6 mol of h2o the main noncondensable components amounted to 97 4 mol co2 1 5 mol so2 0 6 mol h2s and 0 35 mol n2 the higher h2s so2 ratio values found in 2006 as compared to those reported before the 2005 eruption reveal a significant hydrothermal contribution to the fumarolic emissions 3he 4he ratios measured at mina azufral fumarolic discharges showed values of 17 88 0 25 ra indicating a mid ocean ridge basalts morb and a galapagos plume contribution of 53 and 47 respectively

δd and δ18o variations of the magmatic system beneath deception island volcano antarctica implications for magma ascent and eruption forecasting abstract geochemistry of volatiles in active volcanoes provides insights into the magmatic processes and evolution at depth such as magma evolution and degassing which can be implemented into volcanic hazards assessment deception island is one of the most active volcanoes in antarctica with more than twenty explosive eruptions documented over the past two centuries hydrogen and oxygen isotopic variations in the volatiles trapped in the deception island rocks glass and melt inclusions in phenocrysts provide essential information on the mechanisms controlling the eruptive history in this volcanic suite thus understanding the petrological and related isotopic variations in the island has the potential to foresee the possible occurrence and its main eruptive features of a future eruption the new isotopic results of this study combined with exhaustive petrologic knowledge reveal in deception island i fast ascent and quenching of most magmas preserving pre eruptive magmatic signal of water contents and isotopic ratios with local modification by rehydration due to glass exposition to seawater and by meteoric and fumarolic waters ii a plumbing system s variable with time and currently dominated by closed system degassing leading to explosive eruptions iii control on the interactions of ascending magmas with the surface waters producing hydrovolcanic activity throughout the two main fault systems in deception island and at different magma stagnation depths these results can be considered in further studies of volcanic monitoring to improve the capability to interpret geophysical data and signals recorded during volcanic unrest episodes and hence forecast volcanic eruptions and related hazards

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

anomalous diffuse co2 emissions at the masaya volcano nicaragua related to seismic volcanic unrest anomalous changes in the diffuse emission of carbon dioxide within the masaya caldera have been observed before two seismic events that occurred at 10 and 30 km from the observation site their epicenters are located respectively south of managua in las colinas 4 3 magnitude and the xiloa caldera 3 6 magnitude in 2002 and 2003 recorded by the geochemical station located at el comalito masaya volcano nicaragua anomalous increases were observed which occurred around 50 and 8 days before the main seismic event that took place in las colinas and 4 days before the seismic swarm at the xiloa caldera with a maximum co2 efflux of 9 3 and 10 7 kg m 2 day 1 respectively the anomalous co2 efflux increases remained after filtering with multiple regression analysis was applied to the co2 efflux time series which indicated that atmospheric variables during the first 4 months explained 23 co2 variability whereas during the rest of the time series co2 efflux values are poorly controlled with only 6 the observed anomalies of the diffuse co2 emission rate might be related to pressure changes within the volcanic hydrothermal system and or to geostructural changes in the crust due to stress strain changes caused before and during the earthquakes formation and seem not to be related to the activity of the main crater of masaya volcano

hydrological and geochemical change related to volcanic activity of usu volcano japan abstract mt usu is a stratovolcano located on the southern side of the toya caldera in hokkaido japan in historical times it emitted dacitic products associated to remarkable crustal deformations usu volcano erupted on march 31st 2000 after 23 yr of dormancy and this eruption was the fourth in the 20th century secular variations in water levels temperature and chemical compositions of thermal water have been observed around usu volcano the water levels decreased since october 1999 6 months prior to the eruption the decrease in water levels is a precursory change and is probably due to leakage of thermal water from the shallow aquifer hosting it no variations in temperature and chemical composition of thermal water were evident prior to the eruption however in a few wells the temperature of the thermal water increased by up to 15 c with respect to the pre eruptive values moreover the concentration of some solutes na k cl and so4 became higher after the eruption these thermal and chemical changes are ascribable to increased input of a deep hydrothermal liquid into the shallow groundwater aquifer

carbon dioxide degassing by advective flow from usu volcano japan magmatic carbon dioxide co2 degassing has been documented before the 31 march 2000 eruption of usu volcano hokkaido japan six months before the eruption an increase in co2 flux was detected on the summit caldera from 120 september 1998 to 340 metric tons per day september 1999 followed by a sudden decrease to 39 metric tons per day in june 2000 3 months after the eruption the change in co2 flux and seismic observations suggests that before the eruption advective processes controlled gas migration toward the surface the decrease in flux after the eruption at the summit caldera could be due to a rapid release of co2 during the eruption from ascending dacitic dikes spreading away from the magma chamber beneath the caldera

diffuse co2 efflux from iwojima volcano izu ogasawara arc japan abstract iwojima volcano located on the southernmost part of the izu ogasawara arc is characterized by the extrusion of trachyte or trachy andesite lavas and pyroclastic rocks of holocene and surface thermal manifestations small phreatic explosions have been recorded frequently during the last 100 years with the most recent in 1999 and 2001 in order to elucidate the behavior of volcanic volatiles and to assess the potential activity of this volcano diffuse co 2 efflux co 2 content and 13 c co 2 in soil gas and soil temperature at 30 cm depth were measured at 272 sites in march 2000 112 sites in december 2000 and 40 sites in december 2001 we found that high co 2 efflux values of more than 100 g m 2 day 1 occurred at several locations on motoyama volcano corresponding with high soil temperatures more than 60 c at 30 cm depth region and with areas where co 2 with magmatic 13 c was observed here the magmatic 13 c determined for fumarolic co 2 data ranged from 2 to 3 which is clearly higher than magmatic gas values 8 to 2 typically found in island arc settings around the world however this can be explained in terms of carbon isotope fractionation between calcite and co 2 under subsurface temperature and pressure conditions at iwojima a total efflux of co 2 for iwojima volcano is estimated to be 760 t day 1 with a magmatic contribution of about 450 t day 1 this value is rather high compared with other volcanoes in island arc settings since iwojima has no visible plume almost all volcanic co 2 is released as diffuse efflux through the volcanic edifice

a magmatic source for fumaroles and diffuse degassing from the summit crater of teide volcano tenerife canary islands a geochemical evidence for the 2004 2005 seismic volcanic crisis the present work reports the results of 15 studies of diffuse co2 degassing performed at teide volcano crater canary island spain and the chemical and isotopic compositions of fluids discharged from a fumarolic field located at the top of the volcano as measured between 1991 and 2010 a higher contribution of magmatic gases accompanied by enhanced total diffuse co2 emissions were observed in relation with a seismic crisis that occurred in tenerife island between 2001 and 2005 with the main peak of seismic activity between april and june 2004 a significant pulse in total diffuse co2 emission was observed at the crater of teide up to 26 3 t day 1 in 2001 in december 2003 the chemical composition of the teide fumarole changed significantly including the appearance of so2 an increase in the hcl and co concentrations and in the c2h6 c2h4 and c3h8 c3h6 ratios and a decrease in the h2s ch4 and c6h6 concentrations and in the gas steam ratio a few months after a drastic decrease in seismic activity the so2 hcl and co concentrations and the c2h6 c2h4 and c3h8 c3h6 ratios strongly decreased whereas the ch4 and c6h6 concentrations and the gas steam ratios increased according to the trends shown by both the geochemical parameters and the seismic signals late in the observation period the risk of a rejuvenation of volcanic activity at teide is considered to be low the associated temporal changes in seismic activity and magmatic degassing indicate that geophysical and fluid geochemistry signals in this system are related future monitoring programs aimed at mitigating volcanic hazard on tenerife island should involve coupled geophysical and geochemical studies

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

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

lithium systematics in howardite eucrite diogenite meteorites implications for crust mantle evolution of planetary embryos we present lithium li abundances and isotope compositions in a suite of howardites eucrites and diogenites heds these meteorites most likely originated from asteroid vesta and were delivered to earth by a series of independent impact events the li concentrations show striking differences between li poor diogenites plus cumulate eucrites and li enriched eucrites whilst howardites have li abundances intermediate between eucrites and diogenites contrary to li elemental inter group differences li isotope compositions are irresolvable among these individual groups of hed meteorites despite their wildly distinct petrography attesting to insignificant li isotope fractionation during formation of a thick basaltic crust by melting of the vestan mantle the mean li isotope composition of bulk silicate vesta is estimated at 3 7 0 6 1 intermediate to that of the earth versus mars and moon but identical with these terrestrial bodies within uncertainty this further validates largely homogeneous inner solar system solids from the li isotope perspective and supports the lack of loss of moderately volatile elements from planetary embryos during their magmatic histories because li does not follow depletion trends inferred from more volatile elements pasamonte eucrite has the same li isotope composition as other eucrites although it may not be directly linked to vesta these observations are also important for generating li elemental and isotope signatures in juvenile basaltic crusts of large terrestrial planets and numerous planetary embryos in the early solar system a combination of cv l chondrites may be less suitable for building vesta from li perspective but this may face sampling bias of available data and only further analyses may resolve this issue alternatively significant shift of 1 towards heavier li isotope compositions must have occurred during thermal processing of cv l 2 2 2 8 mixture in order to account for the observed li isotope systematics in hed meteorites no correlation is observed between li versus zn fe or si isotopes respectively implying unrelated processes of forming stable isotope variations observed in hed meteorites

diffuse emission of co2 from the fossa crater vulcano island italy numerous measurements of co2 degassing from the soil carried out with the accumulation chamber method indicate that in the period april july 1995 the upper part of the fossa cone released a total output of 200 t d 1 of co2 which corresponds to approximately 1000 t d 1 of steam these large amounts of fluids are of the same order of magnitude as those released by the high temperature fumarolic field located inside the crater the spatial distribution of soil gas fluxes shows that the main structures releasing co2 are the inner slopes of the crater and a nw se line located ne of the crater rim which correspond to the main direction of vulcano island active faults the comparison of the co2 maps with the soil temperature distribution derived from both direct measurements and airborne infrared images indicates the occurrence of extensive condensation of fumarolic steam within the upper part of the fossa cone whose total amount is comparable to the rainfall budget part of the condensate which originates from this process contributes to the recharge of the phreatic aquifer of porto plain modifying the chemical and isotopic composition of the groundwater

geochemical evidences of seismo volcanic unrests at the nw rift zone of tenerife canary islands inferred from diffuse co 2 emission we report the results of 49 soil co2 efflux surveys by the accumulation chamber method at the north west rift nwr zone of tenerife island canary islands the surveys were carried out from 2000 to 2016 to evaluate the temporal and spatial variations of co2 efflux and their relationships with the volcanic and seismic activity at tenerife soil co2 efflux values ranged from non detectable 0 5 g m 2 day 1 up to 141 g m 2 day 1 with the highest values measured in may 2005 whereas total co2 emission rates ranged between 52 and 867 t day 1 metric tons per day isotopic analyses of soil gas in carbon dioxide 13c co2 suggest a mixing between organic and atmospheric co2 with a small contribution of deep seated co2 the main temporal variation in the total co2 output does not seem to be driven by external factors it shows a clear temporal correlation with the onsets of seismic activity subsurface magma degassing affecting the central part of the island is proposed as a cause for the observed changes in the total output of diffuse co2 emission as well as for the spatial distribution of soil co2 efflux

diffusive helium emissions as a precursory sign of volcanic unrest significant increases in helium emissions from the soil and 3 he 4 he ratios in groundwater on el hierro island canary islands spain were observed prior to the 2011 2012 submarine eruption off the coast of the island the changes of diffusive helium emissions rate were observed one month prior to the submarine eruption onset 12 october 2011 and the major increase preceded increases in seismic energy release during the volcanic unrest measured 3 he 4 he ratios in groundwaters from a well in el hierro island increased from 2 3 r a to 7 2 r a r a 3 he 4 he ratio in air 1 month prior to the eruption onset and reached a peak of 8 2 r a indicating a dominant magmatic contribution to the dissolved gases in ground waters 3 he 4 he values and diffusive helium emission studies have been extremely important for forecasting the onset of the volcanic unrest and subsequent volcanic eruption an aseismic exsolution of magmatic gases from magma bodies beneath el hierro island through fractures and vertical permeability structures increased the diffusive helium emission rate prior to episodes of seismic energy release associated with the volcanic unrest

spatial domain analysis of carbon dioxide from soils on vulcano island implications for co2 output evaluation abstract the carbon dioxide emissions of volcanoes have been targeted as effective contributors of co 2 to the atmosphere however different sources can be effective and active at the same time in the generation and release of co 2 in volcanic zones since isotopic fingerprinting of co 2 allows the precise identification of different sources coupling carbon isotope and co 2 flux measurements enables the evaluation of the mass contribution of each source to the carbon dioxide emissions this paper accounts for the first extensive spatial analysis of coupled measurements of carbon isotopologues of co 2 in the soil gases and co 2 fluxes discharged by soils on vulcano island an innovative method has been designed tested and fine tuned in the laboratory to measure 13 c co 2 values directly in field using a new type of laser based isotopologues analyzer namely a deltaray thermo fisher scientific the method can be used to determine the carbon isotope composition across the full range of co 2 concentrations in the soil gases 0 100 vol these data have been combined with measurements of the co 2 contents in the soil gases to distinguish co 2 from deep origins from co 2 of biogenic origin in the inhabited area of vulcano porto the method of evaluating the amount of deep origin co 2 in the soil gases is widely applicable in volcanic and geothermal zones for evaluation and monitoring purposes for both gas and volcanic hazards

multi scale observations of the variability of magmatic co2 emissions mammoth mountain ca usa abstract one of the primary indicators of volcanic unrest at mammoth mountain is diffuse emission of magmatic co 2 which can effectively track this unrest if its variability in space and time and relationship to near surface meteorological and hydrologic phenomena versus those occurring at depth beneath the mountain are understood in june october 2013 we conducted accumulation chamber soil co 2 flux surveys and made half hourly co 2 flux measurements with automated eddy covariance and accumulation chamber auto chamber instrumentation at the largest area of diffuse co 2 degassing on mammoth mountain horseshoe lake tree kill hltk estimated co 2 emission rates for hltk based on 20 june 30 july and 24 25 october soil co 2 flux surveys were 165 172 and 231 t d 1 respectively the average june october co 2 emission rate estimated for this area was 123 t d 1 based on an inversion of 4527 eddy covariance co 2 flux measurements and corresponding modeled source weight functions average daily eddy covariance and auto chamber co 2 fluxes consistently declined over the four month observation time wavelet analysis of auto chamber co 2 flux and environmental parameter time series was used to evaluate the periodicity of and local correlation between these variables in time frequency space overall co 2 emissions at hltk were highly dynamic displaying short term hourly to weekly temporal variability related to meteorological and hydrologic changes as well as long term monthly to multi year variations related to migration of co 2 rich magmatic fluids beneath the volcano accumulation chamber soil co 2 flux surveys were also conducted in the four additional areas of diffuse co 2 degassing on mammoth mountain in july august 2013 summing co 2 emission rates for all five areas yielded a total for the mountain of 311 t d 1 which may suggest that emissions returned to 1998 2009 levels following an increase from 2009 to 2011

eocene calibration of geomagnetic polarity time scale reevaluated evidence from the green river formation of wyoming we reevaluate the eocene geomagnetic polarity time scale on the basis of single crystal 40 ar 39 ar ages for air fall tuffs from the wilkins peak member of the green river for mation of wyoming tuff 6 is dated as 49 1 6 0 2 ma and tuff 3 is dated as 50 4 6 0 3 ma maximum estimate when combined with published magnetostratigraphic con straints these age determinations suggest that the currently accepted age of chron c22r is 1 5 2 5 m y too old which supports a significantly longer duration for the early eocene for the early eocene climatic optimum and the wasatchian north american land mam mal age

soil gas emanations as precursory indicators of volcanic eruptions field measurements conducted on several active volcanoes in italy the lesser antilles and indonesia demonstrate the common occurrence of diffuse soil gas emanations from the volcanic piles at distances from active craters or fumarolic zones these emanations consist essentially of carbon dioxide and rare gases and their genetic link with crater fumaroles and or magma degassing at depth can be verified both chemically and isotopically we emphasize here the potential use of these fluids for continuous volcano monitoring and eruption forecasting

unmanned aerial vehicle measurements of volcanic carbon dioxide fluxes i we report the first measurements of volcanic gases with an unmanned aerial vehicle uav the data were collected at la fossa crater vulcano italy during april 2007 with a helicopter uav of 3 kg payload carrying an ultraviolet spectrometer for remotely sensing the so 2 flux 8 5 mg d 1 and an infrared spectrometer and electrochemical sensor assembly for measuring the plume co 2 so 2 ratio by multiplying these data we compute a co 2 flux of 170 mg d 1 given the deeper exsolution of carbon dioxide from magma and its lower solubility in hydro thermal systems relative to so 2 the ability to remotely measure co 2 fluxes is significant with promise to provide more profound geochemical insights and earlier eruption forecasts than possible with so 2 fluxes alone the most ubiquitous current source of remotely sensed volcanic gas data

deep co2 release revealed by stable isotope and diffuse degassing surveys at vulcano aeolian islands in 2015 2018 abstract the partitioning of carbon dioxide co2 released by soils at vulcano island aeolian islands italy was performed by combining the co2 flux and the carbon isotope measurements based on this method the amount of co2 of volcanic origin was quantified six times during the period 2015 2018 the data analysis allowed us to establish the correlation between co2 soil degassing and changes in the contribution of volcanic fluids carbon isotope determinations were performed in situ to enhance the coverage of data collection in space and time these data were combined with both the co2 contents in the ground gases and the soil co2 flux the amount of volcanic co2 was distinguished from that of biogenic origin by implementing a three component mixing model the results of this study indicate that the increase in co2 output in september 2018 reflects the increase in volcanic gas emissions the measurement method and analysis presented in this work are sufficiently general to be applicable to the monitoring programs of active volcanoes

soil co2 emissions at furnas volcano sao miguel island azores archipelago volcano monitoring perspectives geomorphologic studies and land use planning application accepted for publication in journal of geophysical research copyright 2010 american geophysical union