mass and heat flux of volcanic gas discharging from the summit crater of iwodake volcano satsuma iwojima japan during 1996 1999 abstract volcanic gas of iwodake has been discharged continuously from high temperature 900 c maximum fumaroles and a degassing vent which formed on the central floor of the summit crater after 1994 although most of the high temperature fumaroles located on the crater wall before 1991 many fumaroles appeared on the crater floor associated with the vent opening suggesting a shift of thermal activity from the peripheral to the central crater a large amount of volcanic gas has been discharged from the fumaroles and vent since heat has been transferred from ascending gas to the surrounding soil a region showing a surface temperature anomaly has developed around the fumaroles and vent to quantify iwodake thermal activity heat and volcanic gas mass fluxes were estimated during 1996 1999 using infrared thermal images and plume velocity and temperature data which were observed by a pitot tube and thermocouple the estimated gas mass flux was compared with the cospec data to investigate the accuracy of our estimation the gas mass flux had been decreased from 230 kg s in october 1996 to 30 kg s in november 1999 although the vent diameter had increased from 20 to 70 m during the same period this mass flux variation had indicated the decline of degassing rate the degassing depth was estimated from the volcanic gas mass flux and temperature the depth showed a tendency of magma head migration to shallower depth during 1996 1999 which was consistent with the drastic change of the surface manifestation

sulfur dioxide from nevado del ruiz volcano colombia total flux and isotopic constraints on its origin abstract nevado del ruiz volcano has been releasing extraordinarily large volumes of sulfur dioxide gas from its arenas crater since september 1985 and probably since the renewal of volcanic activity began in late 1984 the combined release from eruptive and passive flux has been approximately 3 4 1 0 10 6 metric tons in the four years after november 1984 this value combined with data of others on pre eruption sulfur content of the magma allows the calculation of a minimum required volume of magma of 0 92 km 3 consideration of the continued high flux and typical ratios of erupted to degassed magma indicate that the true minimum volume of magma involved is probably at least 4 6 9 2 km 3 a systematic study of the various species of sulfur in the volcanic plume and the hydrothermal system has provided a characterization of the geochemistry and sulfur isotopic variation consideration has been given to five potential sources of the sulfur dioxide dissolution of subvolcanic evaporites remobilization and oxidation of native sulfur within summit crater fumaroles large scale release from the hydrothermal system by reduction of sulfate or water rock interaction assimilation and oxidation of a pre existing sulfide deposit and magmatic volatiles the data are most realistically explained by the passage of magmatic gas through the hydrothermal system with some disproportionation of sulfur dioxide to produce the high sulfate content and low ph of the waters this model is also most consistent with the distribution of acid sulfate chloride hot springs high chloride and fluoride content of the hydrothermal waters sulfide deposition within the volcanic pile and the transient increase in sulfate content of the acid sulfate chloride hot springs that reached a maximum approximately one year after the november 1985 eruption the magmatic model is in apparent conflict with the absence of general deformation from the time that data began to be collected about one week before the eruption until the time this manuscript was finalized september 1989 although this conflict cannot be resolved with certainty it is noted that the absence of deformation is only an indication of the lack of magma movement not of the absence of magma an alternative magmatic model considers the available geological data and proposes that the system is related to a large scale caldera in this model the degassing is related to a long term process of exsolution of magmatic volatiles from a large volume of crystallizing magma left from the construction of modern ruiz this model can better explain the combined geological and geophysical data as well as the geochemical and isotopic data the nature of the degassing data at ruiz is interesting because it is an example of an explosive eruption cycle in which the gas flux is actually dominated by passive release the nature of the degassing allows us to hypothesize that some major change in the system occurred in april may 1986 and to predict that the present high flux can be expected to last for another decade

possible magma intrusion revealed by temporal gravity ground deformation and ground temperature observations at mount komagatake hokkaido during the 1996 1998 crisis summary mount komagatake 1131 m above sea level is a subduction related active volcano in hokkaido japan where two phreatic eruptions occurred in 1996 march and 1998 october after 54 years of dormancy we analyse four sessions of geodetic microgravity and ground temperature observations made over a two year period from november 1996 to may 1997 neither significant gravity nor significant elevation changes gps or levelling were observed from may 1997 to november 1997 we observed a slight subsidence 1 2 cm and contraction within 1 cm of the edifice a gravity increase 15 30 gal at the benchmarks inside the 2 km wide summit crater and a local temperature increase of 15 20 c at the summit crater from november 1997 to may 1998 we observed an edifice wide gravity increase of about 15 gal with no significant elevation change for benchmarks outside the summit crater besides this edifice scale variation we recorded a subsidence of about 5 6 cm and apparently no change of gravity inside the summit crater we inverted our data using models of increasing complexity elastic models are able to explain our deformation observations but they cannot explain either the gravity data or the temperature observations satisfactorily we introduced both an isothermal and a non isothermal porous medium filled with fluids to model deformation and gravity variations and we used a fissure model to invert the temperature anomaly our observations are consistent with a model of underground shallow water evaporation occurring as a result of heat rising from a hot and dense body density contrast of 200 kg m 3 of about 1011 kg at 4 5 km depth this interpretation suggests a possible intrusion of a magmatic body within the edifice

birth death and resurrection the life cycle of suprasubduction zone ophiolites 1 suprasubduction zone ssz ophiolites display a consistent sequence of events during their formation and evolution that suggests that they form in response to processes that are common to all such ophiolites this sequence includes the following 1 birth which entails the formation of the ophiolite above a nascent or reconfigured subduction zone this stage is typically characterized by the eruption of arc tholeiite lavas and the formation of layered gabbros and sheeted dike complex 2 youth during which is continued melting of refractory asthenosphere depleted during birth occurs in response to fluid flux from the subducting slab with extensional deformation of the older plutonic suite eruption of refractory lavas and the intrusion of wehrlite pyroxenite 3 maturity with the onset of semistable arc volcanism typically calc alkaline as the subduction zone matures and stabilizes and the intrusion of quartz diorite and eruption of silicic lavas and 4 death which is the sudden demise of active spreading and ophiolite related volcanism which in many cases is linked to collision with an active spreading center and the onset of shallow underthrusting of the buoyant spreading axis expressed as dikes and lavas with oceanic basalt compositions that crosscut or overlie rocks of the older suites 5 resurrection with emplacement by obduction onto a passive margin or accretionary uplift with continued subduction the early stages 1 3 may be diachronous and each stage may overlap in both time and space the existence of this consistent progression implies that ophiolite formation is not a stochastic event but is a natural consequence of the ssz tectonic setting

genesis and evolution of the fumaroles of vulcano aeolian islands italy a geochemical model a geochemical model explaining the presence of fumaroles having different gas composition and temperature at the top of the crater and along the northeastern coast of vulcano island is proposed a pressurized biphase liquid vapor reservoir at the depth of about 2 km is hypothesized energy and mass balance sheets controlp t conditions in the system p t must vary along a boiling curve of brine as liquid is present the co2 content in the steam is governed by the thermodynamic properties of the fluids in the h2 nacl co2 system on the assumption that oxygen fugacity in the system is between the hm fmq oxygen buffers observed so2 h2s co2 co co ch4 ratios in the fumarolic gases at the fossa crater appear in equilibrium with a temperature higher than that observed such as may exist at depth the more reduced gas phases present on the sea side may result from re equilibrium processes in shallower aquifers the suggested model would help in monitoring changes in volcanic activity by analyzing fumarolic gases

influence of soil cover on reducing the environmental impact of spontaneous coal combustion in coal waste gobs a review and new experimental data abstract the process of spontaneous combustion of coal and coal waste gobs including emitted gases condensation of inorganic and organic species in vents and leachable potential are examined in this study which encompasses a literature review and new experimental data furthermore the potential environmental benefits of cover soil reclamation for reduction of atmospheric and water leachable pollutant emissions are also considered the datong district shanxi province is one of the most important coal production areas in china the resulting large accumulations of mining waste are susceptible to spontaneous combustion three coal gangue dumps in the datong region subjected to a range of reclamation conditions were investigated to assess the influence on coal fires coal coal gangue and condensates from gaseous emissions were characterized in terms of chemical composition particle morphology mineralogy and leaching potential the condensates include tar like deposits elemental sulfur gypsum anhydrite ammonium and hg salts and a broad array of al k fe sulfates the latter may give rise to strongly acidic leachates with high metal loads which may pose a serious threat to the environment these findings led to the development of a proposed condensation sequence model for coal gangue fires the presence and distribution of organic compounds in the condensates deposited at vents were used as geothermometers in support of the proposed condensation model additionally the present study has also explored some feasible remediation measures it was found that covering these coal waste dumps with a layer of compacted soils appears to be an excellent cost effective method to reduce spontaneous combustion scavenge pollutants from gaseous emissions and minimize risks associated with the leaching of readily soluble salts condensed on the surface

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

fumarole emissions at mount st helens volcano june 1980 to october 1981 degassing of a magma hydrothermal system abstract this study is an investigation of the chemical changes in the mount st helens fumarole gases up to october 1981 the sources of the fumarole gases and the stability of gas species in the shallow magma system these problems are investigated by calculations of element compositions thermodynamic equilibria and magmatic volatile hydrothermal steam mixing models the fumarole gases are treated as mixtures of magmatic volatiles and hydrothermal steam formed by magma degassing and boiling of local waters in a dryout zone near conduit and dome magma the magmatic volatile fraction is significant in fumaroles with temperatures in excess of the magma cracking temperature 700 c i e the temperature below which cracking is induced by thermal stresses during cooling and solidification linear composition changes of the fumarole gases over time appear to be the result of a steady decline in the magmatic volatile mixing fraction which may be due to the tapping of progressively volatile depleted magma the maximum proportion of hydrothermal steam in the fumaroles rose from about 25 35 in september 1980 to around 50 70 by october 1981 fractional degassing of magmatic co 2 and sulfur also contributed to the chemical changes in the fumarole gases the steady chemical changes indicate that replenishment of the magma system with undegassed magma was not significant between september 1980 and september 1981 extrapolations of chemical trends suggest that fumarole gases emitted at the time of formation of the first dome in mid june 1980 were more enriched in a magmatic volatile fraction and contained a minimum of 9 co 2 calculations show h 2 s is the predominant sulfur species in mount st helens magma below depths of 200 m rapid release of gases from magma below this depth is a plausible mechanism for producing the high h 2 s so 2 observed in mount st helens plumes during explosive eruptions this study suggests that dacite andesite volcanos may emit gases richer in co 2 during the earlier episodes of an eruptive cycle and burden the atmosphere with much more h 2 s than so 2 during explosive eruptions

eddy covariance measurements of hydrothermal heat flux at solfatara volcano italy abstract the first measurements of volcanic hydrothermal water vapor and heat flux using eddy covariance ec were made at solfatara crater italy june 8 25 2001 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 of water vapor varied between 680 and 11 200 g h2o m 2 d 1 heat fluxes varied diurnally with the solar input and the volcanic component of sensible heat ranged from 25 to 238 w m 2 the highest measurements of both sensible and latent heat flux were made downwind of hot soil regions and degassing pools and during mid day the ratio of average volcanic heat both latent and sensible to co2 flux resulted in an equivalent h2o co2 flux ratio of 2 2 by weight which reflects the deep source h2o co2 gas ratio the amount latent heat flux evaporation was determined to be consistent both with what would be expected from the magnitude of co2 fluxes and the fumarolic h2o co2 ratio as well as with observed surface temperatures and wind speeds given a moist soil this suggests that the water vapor that condenses in the shallow subsurface is remobilized at the soil atmosphere interface through variable evaporation dependent on the deep heat flux and surface temperature the results suggest that ec provides a quick and easy method to monitor average h2o co2 ratios continuously in volcanic regions providing another important tool for volcanic hazards monitoring

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

gaseous emissions and sublimates from the truman shepherd coal fire floyd county kentucky a re investigation following attempted mitigation of the fire abstract the truman shepherd coal mine fire floyd and knott counties kentucky has been the subject of several field investigations over the last four years during july and november 2011 and january 2012 field investigations we measured gas emissions collected minerals and characterized the nature of the fire new vents opened over the course of the study and have continued to open since january 2012 coincident with the eastward advance of the fire this is the first study of kentucky coal fires where the original vents were able to be studied in addition to new vents on each subsequent trip neoformed minerals associated with the vents are primarily ammonium sulfates and ammonium chlorides with minor zeolites btex emissions especially benzene vary considerably ranging from relatively low to comparable to those from very large fires such as the ankney coal fire in wyoming vent emission data collected displays a general trend of decreasing carbon dioxide and carbon monoxide emissions from july through january the projected annual greenhouse gas and mercury emissions from the fire are 65 69 t of co 2 4 51 t of co 5 73 t of ch 4 and 1 667 kg hg the november 2011 co co 2 ratios are indicative of more complete combustion than at any other time during the study possibly indicative of decreased moisture in the system

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

japanese volcanoes visualized with muography high energy muons that are generated via the reaction between primary cosmic rays and the earth s atmosphere can be used to map out the density distribution in shallow parts of a volcano s interior

calculation of strong ground motion due to an extended earthquake source in a laterally varying structure abstract lateral heterogeneity of the crust combined with the complexity of an extended earthquake source may account for observations of strong ground motion not easily explained by simplified source models in a laterally homogeneous medium both the effects of an extended source and lateral heterogeneity can be examined using a forward modeling technique that combines distributed nonuniform slip on a fault plane with dynamic ray tracing in a three dimensional medium using this technique velocity seismograms are calculated at ranges less than 10 km for a finite source which occurs in a wedge shaped zone of low velocity this structure is chosen to approximate the structure of fault zones found in reflection and refraction surveys across active faults in california iterative paraxial ray tracing is used to solve the two point ray tracing problem the low velocity zone surrounding the fault causes arrivals in the laterally varying structure to be delayed and rays to leave the fault more closely to the fault normal at most locations examined the effect of the three dimensional structure on isochrone velocity is small compared to the effects on geometric spreading and radiation pattern because rays are bent substantially in the near source region the seismograms calculated for the laterally varying structure vary substantially in amplitude and polarity from seismograms calculated for the laterally homogeneous structure

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

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

volcanic steam output directly measured in fumaroles the observed variations at vulcano island italy between 1983 and 1987 the mass of steam emitted by the fumaroles of the crater of vulcano aeolian islands italy was evaluated by using a direct measuring method measurements were effected with this method between 1983 and 1987 in nine field campaigns the results of which are given in this paper the steam flux measurements were performed by an instrument expressly designed for steam condensation the estimates of the thermal energy transported daily by the steam gave values of up to 10e12 j the sharp variations in the total mass outputs recorded in 1984 and 1985 are here interpreted as being a consequence of the probable accumulation of fluid pressure at depth during the evolution of volcanic activity the different results obtained from the various areas of the fumarolic field during the evolutionary phases have led to the hypothesis that different subsystems exist that feed the fumaroles and that their activity is triggered by volcano tectonics this method can be applied in the evaluation of both fumarolic steam and thermal energy outputs and therefore it is particularly useful in geothermal exploration in the evaluation of the environmental impact of volcanic degassing and in the forecasting of volcanic eruptions the evaluation of the steam output is also useful for quantifying the release of other gaseous species and giving univocal interpretations regarding their variations in concentrations furthermore this direct method provides a new way of calibrating the flux estimates effected by other telemetric techniques lidar cospec etc

evaluation methods of heat discharge and their applications to the major active volcanoes in japan abstract the rates at which thermal energy is released by non eruptive mechanisms associated with active volcanoes in japan have been estimated from surface temperature distributions or from shapes of the fumarolic plume rise values of 5 3 x 107 w and 1 2 x 108 w have been calculated for non eruptive release rates in 100 km segments of the northeast and the southwest japan arc respectively it appears that non eruptive heat discharge is of the same order as that caused by eruptions

visible and invisible volcanic plumes 1 volcanic plumes discharging from craters or fumaroles are usually observed at active volcanoes these plumes are divided into two categories from their appearance one is a transparent invisible plume composed of volcanic gases and the other is a white visible plume containing water droplets in addition to the vapors the difference in plume visibility is caused by changes in the conditions that control water condensation in the plume we present a simple model describing the condition for the water condensation in the plume as a function of the exit temperature volcanic gas composition atmospheric temperature and humidity and tested the model with a field observation the result indicates that we can estimate the exit temperature from the visibility of the plume under known atmospheric conditions

sulfur dioxide and particles in quiescent volcanic plumes from poas arenal and colima volcanos costa rica and mexico measurements of so2 emission rates and concentrations and of particle distribution size shape and composition were made in quiescent volcanic plumes emitted into the troposphere from poas and arenal volcanos costa rica and colima volcano mexico so2 emission rates were 700 180 metric tons per day t d for poas 210 30 t d for arenal and 320 50 t d for colima the concentrations of so2 calculated from the cospec lidar data were 5 380 ppb concentrations of so2 measured directly by flame photometry were 10 250 ppb particles collected in the plumes with a quartz crystal microbalance impactor were mostly less than 3 m in diameter and consisted of droplets of dilute sulfur bearing solutions and minor amounts of larger silicate particles coated with a sulfur bearing film or crust total particle concentrations were 4 7 g m3 for poas and 18 8 g m3 for colima comparison of concentrations of so2 in the plumes with gas samples collected at fumaroles on the ground suggests that the plumes are diluted by the atmosphere by factors of up to 105

broadband seismic observations at satsuma iwojima volcano japan this paper reports the results of preliminary analysis of broadband seismic observations conducted at satsuma iwojima volcano japan the recorded broadband data show a wide variety of seismic features small m 0 short period volcanic earthquakes characterized by a long 5 s emergent phase and by nearly identical waveforms are located at the very shallow part of the summit crater long period seismic pulses synchronized with a regular amplitude modulation of volcanic tremor have an interval of approximately 46 to 50 min each of the long period pulses has almost identical waveform polarization of the long period events suggests a very shallow source which can be interpreted as a result of a volume expansion mechanism the correlation between the long period seismic pulses and volcanic tremor seems to be associated with magma convection and the degassing process inside the conduit of the volcano

fumarole monitoring with a handheld infrared camera volcan de colima mexico 2006 2007 abstract this paper describes a methodology for the monitoring of fumarole temperatures at medium ranges 6 km using a handheld infrared camera wavelength range 8 13 5 m as a relationship between fumarole temperatures gas flux and volcanic activity has been demonstrated by a number of studies fumarole temperature data has a potential use as a monitoring tool volcan de colima is an andesitic stratovolcano with a 300 m diameter summit crater formed by the destruction of the 2004 lava dome by a series of explosions in 2005 between january 2006 and august 2007 sequences of thermal images were recorded from a viewpoint 6 km to the north during regular 24 48 hour monitoring excursions the temperatures of fumaroles on the crater rim and the ground surface on the volcano s flanks were measured a methodology was developed to remove data affected by clouds or volcanic water vapour based on rates of temperature change and scatter within the data for the remaining data it is demonstrated mathematically that at this range typical variations in atmospheric transmissivity will affect the apparent temperatures by 2 c while a 25 change in fumarole heat flux would change it by 5 10 c the mean night time apparent temperature of the fumaroles was calculated for each excursion and showed an irregular decline over the 19 month period subtracting the radiant heat flux of flank rocks from those of the fumaroles removes seasonal variations and gives the clearest view of trends in the fumarole heat flux a sharp drop in fumarole temperature during february 2007 coincided with the emergence of a lava dome in the crater the declining fumarole temperature is interpreted to reflect decreasing gas flux from the crater in line with a change in eruptive regime from frequent small ash rich explosions to slow effusion of lava

linearized inversion for fault rupture behavior application to the 1984 morgan hill california earthquake we present a technique to infer the rupture history of an earthquake from near source records of ground motion unlike most previous studies each point on the fault is assumed to slip only once when the rupture front passes with a spatially variable slip intensity in this parameterization the data are linearly related to slip intensity but nonlinearly related to rupture time we perform a linearized inversion for slip intensity and rupture time by iteratively perturbing an assumed starting model the inverse problem for the model perturbation is solved using a tomographic back projection technique smoothing and inequality constraints are applied to ensure that the resulting solution is stable and feasible asymptotic ray theory is used to calculate theoretical seismograms and partial derivatives with respect to model parameters in test cases with noisy synthetic data sets we found that it is possible to distinguish between rupture models having variable slip amplitude and models having variable rupture velocity provided the station coverage is adequate we apply the technique to recordings of the april 24 1984 morgan hill earthquake the results indicate that slip amplitude on the fault plane was extremely variable and that the rupture front did not propagate uniformly away from the hypocenter in particular rupture was delayed on a 12 km2 section of the fault approximately 14 km to the southeast of the hypocenter the rupture front surrounded the region which subsequently failed with a component of rupture propagation back toward the hypocenter similar behavior has been observed in dynamic rupture models with stress or strength inhomogeneities this segment of the fault ruptured with a large slip amplitude releasing 12 of the total seismic moment from 4 of the total area of the aftershock zone the surface trace of this section of the fault is characterized by a complex left step that could act to increase the normal stress acting across the fault however the distribution of aftershocks suggests that the fault at depth is simpler and that it may bend to the right in either case our rupture model suggests that this segment of the fault represents an asperity which initially resisted rupture but eventually ruptured massively we estimate the shear fracture energy for this earthquake to be 2 106 j m2

thermal survey of mount etna volcano from space surveys of ground thermal anomalies and the monitoring of their evolution are of great importance in the study of volcanoes thermal monitoring techniques could be used in conjunction with classical monitoring tools i e seismological and deformation networks to give better predictions of the onset of a volcanic event in order to detect and emphasize small anomalies in the surface temperature of the ground we have developed a new method based on the joint use of two satellite radiometers the noaa advanced very high resolution radiometer avhrr for the quality of its thermal band calibration and the landsat thematic mapper tm for its high spatial resolution this method is applied to the mount etna volcano sicily and reveals several thermal anomalies one anomaly is already known and is associated with the permanently active craters of the summit zone the second is a larger area where an eruption occurred one week after the data acquisition 10 23 86 the general trend of the thermal anomalies leads to recognition of a large semi circular intrusive zone corresponding to the borders of the well known valle del bove

rates of sulfur dioxide and particle emissions from white island volcano new zealand and an estimate of the total flux of major gaseous species airborne correlation spectrometry cospec was used to measure the rate of so2 emission at white island on three dates i e november 1983 1230 300 t d november 1984 320 120 t d and january 1985 350 150 t d t metric tons the lower emission rates are likely to reflect the long term emission rates whereas the november 1983 rate probably reflects conditions prior to the eruption of december 1983 the particle flux in the white island plume as determined with a quartz crystal microbalance cascade in november 1983 was 1 3 t d unusually low for volcanic plumes the observed plume particles as shown from scanning electron microscopy include halite native sulfur and silicates and are broadly similar to other volcanic plumes

evolution of fumarolic gases boundary conditions set by measured parameters case study at vulcano italy physical chemical and isotopic parameters were measured in fumaroles at the vulcano crater and in drowned fumaroles near the beach the data were used to define boundary conditions for possible conceptual models of the system crater fumaroles time variations of co2 and so2 concentrations indicate mixing of saline gas rich water with local fresh water cl br ratios of 300 400 favour sea water as a major source for cl brand part of the water in the fumaroles cl concentrations and d values revealed independently amixing of 0 75 sea water with 0 25 local freshwaterin furmarole f 5 during september 1982 patterns of parameter correlation and mass balances reveal that co2 s nh3 and b originate from sources other than sea water the co2 value of 13c 2 o favours at least partial origin from decomposition of sedimentary rocks rather than mantle derived material radiogenic4he 1 3 lo 3 ccstp g water and radiogenic40ar 10 6 10 4 ccstp g water are observed 4he 40ar radiogenic 1 2 well in the range of values observed in geothermal systems drowned fumaroles strongly bubbling gas at a pond and at the beachappears to have the same origin and initial compositionas the crater fumaroles 2 km away the fumarolic gas is modified by depletion of the reactive gases caused by dissolution in shallow water atmospheric ne ar kr and xe are addeden route some radiogenic he and ar are maintained the vulcano system seems to be strongly influenced by the contribution of sea water and decomposition of sedimentary rocks evidence of magmatic contributions is mainly derived from heat

ducks low cost thermal monitoring units for near vent deployment abstract during 1999 we designed and tested a thermal monitoring system to provide a cheap robust modular real time system capable of surviving the hostile conditions encountered proximal to active volcanic vents in november 2000 the first system was deployed at pu u o o kilauea hawai i to target persistently active vents aside from some minor problems such as sensor damage due to tampering this system remained operational until january 2004 the success of the prototype system led us to use the blueprint for a second installation at stromboli aeolian islands italy this was deployed dug into a bomb proof bunker during may 2002 and survived the april 2003 paroxysmal eruption despite being located just 250 m from the vent in both cases careful waterproofing of connectors and selection of suitable protection has prevented water damage and corrosion in the harsh atmosphere encountered at the crater rim the pu u o o system cost us 10 000 and comprises four modules sensors transmission and power hub repeater station and reception site the sensor component consists of three thermal infrared thermometers housed in pelican cases fitted with germanium arsenide selenium windows two 1 field of view fov sensors allow specific vents to be targeted and a 60 fov sensor provides a crater floor overview a hard wire connection links to a pelican case housed microprocessor modem and power module from here data are transmitted via a repeater site to a dedicated pc at the hawaiian volcano observatory here data are displayed with a delay of 3 s between acquisition and display the modular design allows for great flexibility at stromboli 1 and 15 fov sensor modules can be switched depending changes in activity style and crater geometry in addition a direct line of site to the stromboli reception center negates the repeater site requirement reducing the cost to us 5500 for a single sensor system we have also constructed self contained units with internal data loggers for us 1500 unit these have been tested at kilauea stromboli etna masaya santiaguito fuego pacaya poas soufriere hills villarrica and erta ale these instruments have proved capable of detecting thermal signals associated with 1 gas emission 2 gas jetting events 3 crater floor collapse 4 lava effusion 5 lava flow in tubes 6 lava lake activity 7 lava dome activity and 8 crater lake skin temperature

a two phase hydrothermal cooling model for shallow intrusions abstract an approximate model for shallow magma groundwater interaction is developed the model assumes a compressible two phase hydrothermal zone separated from hot mobile magma by a zone of cooler magma having a more plastic rheology and vanishing permeability fig 1 with the model it is shown that the compressibility of vapor causes increases in the cooling rates of shallow intrusions with increasing depth of intrusion furthermore hydrothermal infiltration i e motion of the liquid vapor groundwater zones toward the magma is shown to occur if the rate at which heat is removed by the hydrothermal zone exceeds the rate of heat transfer by conduction across the impermeable plastic zone maximum infiltration rates of several meters per year are predicted by a one dimensional infiltration model other calculations show that the environment exterior to convecting magma which includes the hydrothermal regime is typically far more resistive to heat flow than the convecting magma itself as a result the environment not magma convection determines the cooling rate of typical intrusions as well as the temperature gradients within those intrusions

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

giant tuff cone and 12 km wide associated caldera at ambrym volcano vanuatu new hebrides arc abstract ambrym in the new hebrides arc has been considered as an effusive basaltic volcano the present paper discusses the general structure of this edifice which consists of a basal shield volcano topped by an exceptionally large tuff cone surrounding a 12 km wide summit caldera dacitic pyroclastic flow deposits are exposed in the lower part of the tuff series they grade upward into composite sequences of bedded surtseyan type hyaloclastites ash flow deposits and fallout tephra which are essentially basaltic in composition in such a way that the tuff cone may be considered as mainly basaltic the relationship between the eruption of pyroclastics and the collapse event precludes a classical model of caldera formation at a basaltic volcano in which quiet subsidence i e kilauea type is the dominant mechanism interpretation of the tuff series implies intervention of external water and suggests both explosive and collapse mechanisms a model of caldera formation which assumes an enlargement of the ring fracture during a first plinian and dacitic then essentially hydrobasaltic eruption is proposed

chronostratigraphic assignment of volcanopelagic strata above the coast range ophiolite the chronostratigraphic assignments of radiolarian cherts tuffaceous mudstones and volcaniclastic strata referred to herein as volcanopelagic succession overlying the coast range ophiolite in the coast ranges of california have been refined on the basis of additional field data and recent revision of the pessagno and others radiolarian biostratigraphic zonation for the middle and upper jurassic of north america revision of this zonation scheme accomplished through the integration of radiolarian data with ammonite biostratigraphy and geochronometry has enabled close correlation of radiolarian assemblages in north america europe and japan however major differences still exist in the stage assignments of these assemblages among different zonations the pessagno and others scheme is utilized herein to discuss the current chronostratigraphic assignments at five localities in the coast ranges point sal stanley mountain cuesta ridge and llanada in the southern coast ranges and black mountain geyser peak area in the northern coast ranges of california stage assignments for volcanopelagic successions in these areas range from uppermost callovian lower oxfordian to upper tithonian

crater lake heat losses estimated by remote sensing volcanic crater lakes represent the uppermost parts of magmatic hydrothermal systems and can be regarded as calorimeters in order to estimate subsurface heat fluxes here thermal infrared images recorded by the landsat thematic mapper tm are employed to map surface temperatures across poas costa rica ruapehu new zealand and kawah ijen and kelut indonesia volcano lakes first lake areas are constrained by inspection of the nonthermal bands these estimates are used to define lake pixels in the thermal band and the temperature of each flagged pixel is calculated alternatively the hottest pixel can be assumed to represent the temperature of the whole lake surface mitigating the effects of mixed land water pixels taking appropriate values for air temperature humidity and windspeed surface heat flux densities and power outputs are then derived from bulk aerodynamic or other formulae improved capabilities for monitoring crater lakes will be provided by forthcoming satellite missions notably the enhanced thematic mapper etm and advanced spaceborne thermal emission and reflection radiometer aster

radioisotopic and biostratigraphic age relations in the coast range ophiolite northern california implications for the tectonic evolution of the western cordillera the coast range ophiolite cro in northern california includes two distinct remnants the elder creek ophiolite is a classic suprasubduction zone ophiolite with three sequential plutonic suites layered gabbro wehrlite pyroxenite quartz diorite a mafi c to felsic dike complex and mafi c felsic volcanic rocks the entire suite is cut by late mid oceanic ridge basalt morb dikes and overlain by ophiolitic breccia the stonyford volcanic complex sfvc comprises three volcanic series with intercalated chert horizons that form a submarine volcano enclosed in sheared serpentinite structurally below this seamount are melange blocks of cro similar to elder creek u pb zircon ages from plagiogranite and quartz diorites at elder creek range in age from 165 ma to 172 ma u pb zircon ages obtained from cro melange blocks below the sfvc are similar 166 172 ma 40 ar 39 ar ages of alkali basalt glass in the upper sfvc are all younger at 164 ma radiolarians extracted from chert lenses intercalated with basalt in the sfvc indicate that the sedimentary strata range in age from bathonian unitary association zone 6 6 of baumgartner et al 1995a near the base of the complex to late callovian to early kimmeridgian unitary association zones 8 10 in the upper part the sfvc sedimentary record preserves evidence of a major faunal change wherein relatively small sized polytaxic radiolarian faunas were replaced by very robust oligotaxic nassellarian dominated faunas that included praeparvicingula spp we suggest that cro formation began after the early middle jurassic 172 180 ma collision of an exotic or fringing arc with north america and initiation of a new or reconfi gured east dipping subduction zone the data show that the cro formed prior to the late jurassic nevadan orogeny probably by rapid forearc extension above a nascent subduction zone we infer that cro spreading ended with the collision of an oceanic spreading center ca 164 ma coincident with the oldest high grade blocks in the structurally underlying franciscan assemblage we further suggest that the classic nevadan orogeny represents a response to spreading center collision with shallow subduction of young lithosphere causing the initial compressional deformation and with a subsequent change in north american plate motion to rapid northward drift j2 cusp causing sinistral transpression and transtension in the sierra foothills these data are not consistent with models for late jurassic arc collision in the sierra foothills or a back arc origin for the cro

the 1984 morgan hill california earthquake the morgan hill california earthquake magnitude 6 1 of 24 april 1984 ruptured a 30 kilometer long segment of the calaveras fault zone to the east of san jose although it was recognized in 1980 that an earthquake of magnitude 6 occurred on this segment in 1911 and that a repeat of this event might reasonably be expected no short term precursors were noted and so the time of the 1984 earthquake was not predicted unilateral rupture propagation toward the south southeast and an energetic late source of seismic radiation located near the southeast end of the rupture zone contributed to the highly focused pattern of strong motion including an exceptionally large horizontal acceleration of 1 29g at a site on a dam abutment near the southeast end of the rupture zone

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

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

fluid volcano interaction in an active stratovolcano the crater lake system of poas volcano costa rica rowe g l jr brantley s l fernandez m fernandez j f borgia a and barquero j 1992 fluid volcano interaction in an active stratovolcano the crater lake system of po is volcano costa rica j volcanol geotherm res 49 2351 seismic and geochemical data collected at po is volcano costa rica since 1978 suggest that temperature and chemical variations recorded in subaerial fumaroles and the crater lake are related to episodic release of heat and volatiles associated with hydrofracturing of the upper margin of the shallow magma body power outputs associated with these events approach 600 mw and are superimposed on a baseline energy flux of approximately 200 mw the baseline heat flux suggests a magma solidification rate of 0 012 km3 yr and background volatile release rates of 1000 t d h20 66 t d s 13 t d ci and 0 5 t d f these fluxes are comparable to fluxes of f c1 and s exiting the magmatic hydrothermal system through acidic flank springs and are about a factor of five less than estimated volatile fluxes through summit fumaroles during the high temperature event of 1981 1983 mass balance considerations suggest that heat released at the lake surface is primarily supplied by the ascent of heated brines supplemented by condensation of fumarolic steam calculated average seepage rates out of the lake 450 kg s indicate rapid convection of acidic lake brine through underlying lake sediments and pyroclastic deposits circulation of the extremely corrosive lake brine through the volcanoclastic material beneath the lake may enhance subsurface permeabilities fluxes of rock forming elements observed in the rio agrio basin on the northwest flank of po is suggest that dissolution and removal of volcano elastic material occurs at a rate of approximately 1650 m3 yr however estimated sulfur fluxes from the cooling magma body suggest that porosity created by this dissolution could quickly be filled by the deposition of native sulfur finally analysis of heat and water budgets for the crater lake over the period 1978 1989 indicates that the recent decline and disappearance of the lake was caused by variations in summit rainfall combined with an increase in subsurface heat flow to the lake in 1987 1988 the increase in heat flow is related to continued degassing of high temperature volatiles following a hydrofracturing magma ascent episode that occurred in 1986

physical models of fumarolic flow abstract transport of gas from subsurface magma to the atmosphere is modelled as flow through a narrow rough pipe and through a wider conduit filled with spheres representing flow in a porous pipe macroscopic mass momentum and energy balances are written for a control volume representing a short vertical section of the pipe the balances are solved for a perfect gas with the approximate thermodynamic properties of steam losing heat by steady state radial conduction through the pipe walls with boundary conditions of magmatic temperature at the base of the pipe atmospheric pressure at the surface and an ambient geotherm at a specified distance from the conduit results yield the variation of exit temperature with magmatic source depth conduit radius mass flow rate per unit area distance to ambient temperatures vent porosity and porous particle size two ambient geotherms are used 1 a linear gradient from atmospheric to magmatic temperatures and 2 a hydrothermal geotherm based on water saturation temperatures assuming a hydrostatic pressure gradient because individual vents commonly cluster the porous pipe model is considered to be more realistic than the rough pipe model mainly because the conductive cooling approximation is more likely to remain valid exit temperatures fall as conductive losses increase i e as the source depth increases the conduit narrows the mass flow decreases the distance to ambient temperatures reduces or the ambient geotherm cools the porous pipe model is applied to data from two fumarole fields and indicates magmatic source depths of

the heat source of ruapehu crater lake deductions from the energy and mass balances abstract regular observations of temperature outflow rates and water chemistry of crater lake mt ruapehu new zealand have been made for the last 25 years these data have been used to derive a model of the dynamics of the lake and determine the input of energy mass and chloride from the volcano to the crater lake the recent relatively quiescent state of the volcano when virtually no heat has been input to the lake has also enabled an assessment to be made of the surface heat loss characteristics which play an important role in the model of the lake the modelling suggests that since about 1982 the ratio of the volcanic heat to mass added to the base of the lake is about 6 mj kg which is not compatible with heating of the lake by magmatic steam alone thus only about 50 of the heating has been by magmatic steam it is suggested that heat could be transferred from a magmatic source to the region below the lake by a heat pipe mechanism commonly associated with geothermal systems the simultaneous upward movement of vapour phase and downward movement of liquid phase from condensed vapour allows efficient heat transfer without overall mass transfer the permeability necessary to supply the required heat is of the order of 10 darcy and is consistent with a rubble filled vent for at least the last five years there has been a characteristic pattern in the crater lake temperature record with alternate heating and cooling phases the heating phase generally lasts for one or two months while the cooling phase lasts for six months to a year a possible explanation for this cyclic behaviour is the presence of a layer of liquid sulphur under crater lake acting as a partial barrier between the heat pipe and the lake the unusual variations of the viscosity of liquid sulphur with temperature will mean that at temperatures greater than 160 c the layer of sulphur becomes highly viscous and would block any upwards steam flow and hence stop the heat input to crater lake so producing a cooling phase this blockage would last until the heating from below raised the temperature of the sulphur beyond the high viscosity region so gases could again pass through the sulphur

thermal infrared image analysis of a quiescent cone on piton de la fournaise volcano evidence of convective air flow within an unconsolidated soil abstract we report on the detection of air convection with infrared thermal images for two quasi circular craters 20 m and 40 m wide forming the volcanically inactive cone of formica leo reunion island the thermal images have been acquired from an infrared camera at regular time intervals during a complete diurnal cycle during the night and at dawn we observe that the rims are warmer than the centers of the craters the conductivity contrast of the highly porous soils filling the craters and their 30 slopes are unable to explain the systematic temperature drop from rim to centers we suggest that this signal could be attributed to air convection with gas entering the highly permeable soil at the center of each crater then flowing upslope along the bottom of the soil layer before exiting it along the crater rims to quantify this process we present a two dimensional numerical modelling of air convection in a sloped volcanic soil with a surface temperature evolving between day and night this convection depends on a unique dimensionless equivalent rayleigh number ra eq which is the product of the standard rayleigh number with the volumetric heat capacity ratio of the air and the soil the convective flow is unsteady during some periods the convective flow is entirely confined within the soil and at other times air enters the crater at its center and exits it at the rim crests when ra eq 6000 a value likely compatible with the soil permeability and the geothermal heat flux a very strong transient cold air plume occasionally develops along the center of the crater the interval of time between two plumes only depends on the thermal fluctuations within the top boundary layer of the convective cell and thus is not contrasted by the diurnal cycle the detachment of a cold plume can occur at any time after few days of quiescence and lasts several hours during the whole convective cycle the rim to center temperature drop persists and has an amplitude and a shape having an excellent agreement with that found in the ir images this work constitutes a preliminary step to explore the deep thermal structure of the active caldera of bory dolomieu and could help to improve the understanding of volcanic hazards of the reunion volcano

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

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

silicic volcanism on mars evidenced by tridymite in high sio2 sedimentary rock at gale crater tridymite a low pressure high temperature 870 c sio2 polymorph was detected in a drill sample of laminated mudstone buckskin at marias pass in gale crater mars by the chemistry and mineralogy x ray diffraction instrument onboard the mars science laboratory rover curiosity the tridymitic mudstone has 40 wt crystalline and 60 wt x ray amorphous material and a bulk composition with 74 wt sio2 alpha particle x ray spectrometer analysis plagioclase 17 wt of bulk sample tridymite 14 wt sanidine 3 wt cation deficient magnetite 3 wt cristobalite 2 wt and anhydrite 1 wt are the mudstone crystalline minerals amorphous material is silica rich 39 wt opal a and or high sio2 glass and opal ct volatile bearing 16 wt mixed cation sulfates phosphates and chlorides perchlorates chlorates and has minor tio2 and fe2o3t oxides 5 wt rietveld refinement yielded a monoclinic structural model for a well crystalline tridymite consistent with high formation temperatures terrestrial tridymite is commonly associated with silicic volcanism and detritus from such volcanism in a lake gale catchment environment can account for buckskin s tridymite cristobalite feldspar and any residual high sio2 glass these cogenetic detrital phases are possibly sourced from the gale crater wall rim central peak opaline silica could form during diagenesis from high sio2 glass as amorphous precipitated silica or as a residue of acidic leaching in the sediment source region or at marias pass the amorphous mixed cation salts and oxides and possibly the crystalline magnetite otherwise detrital are primary precipitates and or their diagenesis products derived from multiple infiltrations of aqueous solutions having variable compositions temperatures and acidities anhydrite is post lithification fracture vein fill

volcanology 2020 how will thermal remote sensing of volcanic surface activity evolve over the next decade abstract volcanological remote sensing spans numerous techniques wavelength regions data collection strategies targets and applications attempting to foresee and predict the growth vectors in this broad and rapidly developing field is therefore exceedingly difficult however we attempted to make such predictions at both the american geophysical union agu meeting session entitled volcanology 2010 how will the science and practice of volcanology change in the coming decade held in december 2000 and the follow up session 10 years later looking backward and forward volcanology in 2010 and 2020 in this summary paper we assess how well we did with our predictions for specific facets of volcano remote sensing in 2000 the advances made over the most recent decade and attempt a new look ahead to the next decade in completing this review we only consider the subset of the field focused on thermal infrared remote sensing of surface activity using ground based and space based technology and the subsequent research results this review keeps to the original scope of both agu presentations and therefore does not address the entire field of volcanological remote sensing which uses technologies in other wavelength regions e g ultraviolet radar etc or the study of volcanic processes other than the those associated with surface mostly effusive activity therefore we do not consider remote sensing of ash gas plumes for example in 2000 we had looked forward to a golden age in volcanological remote sensing with a variety of new orbital missions both planned and recently launched in addition exciting field based sensors such as hand held thermal cameras were also becoming available and being quickly adopted by volcanologists for both monitoring and research applications all of our predictions in 2000 came true but at a pace far quicker than we predicted relative to the 2000 2010 timeframe the coming decade will see far fewer new orbital instruments with direct applications to volcanology however ground based technologies and applications will continue to proliferate and unforeseen technology promises many exciting possibilities that will advance volcano thermal monitoring and science far beyond what we can currently envision

gaseous emissions from the lotts creek coal mine fire perry county kentucky abstract the lotts creek coal mine fire is burning in abandoned works of the pennsylvanian hazard no 9 coal perry county kentucky over the few months separating sampling trips the fire showed a definite migration to the south several vents sampled on the first trip were extinct on the second trip the flux of major gases varies from 1100 to 440 000 mg s m 2 co 2 and 2 co with the gas temperature being one of the principal drivers of the emissions variations the higher the temperature the more co 2 produced mercury also showing wide variation from 45 to 740 ng s m 2 could not be measured at all vents due to temperature limitations inherent in the instrument in addition to co 2 co and hg a number of gases among the volatile aliphatic and volatile aromatic compounds are emitted in potentially dangerous amounts

strong motion seismology strong motion seismology is concerned with earthquake ground motion in the amplitude range that poses the threat of human injury or property damage because the occurrence of strong motion cannot be predicted in advance and because the time between significant events at any one place may range from tens to thousands of years strong motion data is recorded on triggered instruments that typically must be maintained in readiness for years between periods of significant recording as a consequence the strong motion data set is sparse because of the engineering need for estimates of future ground motion the scope of the field of strong motion seismology encompasses seismic source theory and any other aspect of seismology that can provide insights helpful in making the best possible estimates given the limited data this relationship with the rest of seismology is a reciprocal one in that strong motion data gives perhaps the best information available on earthquake source processes

continuous monitoring of high temperature fumaroles on an active lava dome volcan colima mexico evidence of mass flow variation in response to atmospheric forcing rapid multichannel monitoring of fumaroles on volcan colima mexico provides new insight into the time scales and magnitudes of fumarole temperature variation temperatures in five fumaroles all located along a single fracture cutting the summit lava dome of the volcano were monitored at 20 min intervals between may 1991 and may 1992 measurements were made using a programmable data logger deployed near the fumarole field and data were radiotelemetered to a nearby volcano observatory at regular intervals mean fumarole temperatures varied between 350 c and 550 c statistical analysis of these time series shows that significant diurnal variation occurs in each fumarole magnitudes of these daily fluctuations are generally between 25 c and 50 c although larger amplitude variations occur especially in cooler fumaroles simultaneous monitoring of atmospheric pressure at the fumaroles indicates that these variations in temperature are inversely correlated with barometric pressure these observations indicate that fumarole temperatures respond to atmospheric forcing a numerical model developed to explore the dependence of fumarole temperature on mass flow demonstrates that many aspects of observed temperature variation are accounted for by mass flow variation resulting from small changes in barometric pressure the relationship between mass flow and fumarole temperature is nonlinear the response of fumarole temperatures to a given change in mass flow is greatest in fumaroles with low mass flow and cool temperatures the nature of this dependence is little affected by fumarole geometry for the cases considered continuous measurement of fumarole temperatures may be an effective means of monitoring local mass flow on volcanoes at volcan colima average temperatures changed by less than 100 c during the 1 year sampling period during and immediately following effusive activity changes in degassing were abrupt and inconsistent along the length of the fracture following this period temperatures decreased gradually and there was a higher degree of correlation between fumaroles the method described here represents a substantial improvement over traditional fumarole monitoring techniques because subtle variation can be quickly identified using standard statistical techniques and the method provides regular information about thermal activity on a volcano minimizing the hazards normally associated with the collection of these data on a regular basis

volcanic lake systematics i physical constraints volcanic lakes have a wide range of characteristics and we make an attempt to delineate the limiting physical conditions for several lake classes the ratio between heat input and heat dissipation capacity of a lake constrains the temperature for perfectly mixed steady state volcanic lakes poorly mixed lakes are also conditioned by this ratio but their temperature structure is also strongly influenced by the hydrodynamics resulting from different mechanisms of heat transfer the steady state temperatures of volcanic lakes are largely determined by the magnitude of the volcanic heat influx relative to the surface area of the lake small lakes have only a small capacity for heat dissipation and their temperature rises quickly with only small heat inputs large lakes are buffered against variations in heat input both the heat dissipation and meteoric water input into a lake are functions of lake surface area and therefore each lake water temperature demands a certain precipitation rate for mass conservation independent of lake size the results of energy mass balance modeling shows that under common atmospheric conditions most steady state volcanic lakes are unlikely to maintain a temperature in excess of 45 50 c validation of the volcanic lake model was performed using published data from yugama lake japan and the keli mutu lakes indonesia also the model was applied to 24 natural systems to provide a baseline assessment of energy fluxes under the model assumptions so future work on those systems can identify nuances in individual systems that deviate from the simple model conditions we recommend the model for use in assessing temperature variations and volcanic lake stability in settings with known physical and atmospheric conditions application of the energy mass balance calculations of model lakes provides a genetic classification scheme largely based on physical process parameters

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

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

long term tir imagery processing for spatiotemporal monitoring of surface thermal features in volcanic environment a case study in the campi flegrei southern italy the tir monitoring system was partially funded by the 2000 2006 national operating programme and by the italian civil protection department in the framework of the 2004 2006 agreement with the istituto nazionale di geofisica e vulcanologia

measuring and interpreting heat fluxes from shallow volcanic bodies using vertical temperature profiles a preliminary test to test the potential of heat flux prospecting in active volcanic areas using shallow temperature data taken along vertical profiles we carried out two thermal profile surveys one not far from yasur cone on tanna island and another inside the caldera of ambrym new hebrides arc southwestern pacific the basic steady heat flux of internal volcanic origin was determined taking into account both conductive and convective heat transfers at both locations there exists over small distances significant differences in the heat flux these differences correspond to shallow sources of heat the use of a network of vertical profiles allowed a heat flux mapping b location of shallow volcanic heat sources and c observation of the detailed structure of the heat release at quiescent but active volcanoes

fluid immiscibility in volcanic environments volatile components enter the atmosphere oceans and other surface waters through pre syn and post eruptive volcanic processes that involve a variety of fluids aluminosilicate poor fluids include aqueous or carbonic to sulfide sulfate chloride fluoride carbonate and phosphate rich compositions in volcanic environments but other more complex combinations of these constituents may be involved giggenbach 1977 roedder 1984 1992 lowenstern 1995 other rare gases and dissolved constituents e g h2 n2 he ar h3bo3 hg ch4 and other hydrocarbon compounds metals and metalloids are also present but in general they are not sufficiently concentrated to form their own phases or control bulk fluid composition and volcanic processes as a result of their diverse compositions volcanic fluids ranging from vapor to liquid exhibit widely different densities and show strong distinctions in heat capacity dielectric behavior viscosity and other chemical and physical characteristics geiger et al 2006a the density of a saline liquid in the system nacl h2o at 50 mpa and 800 c for example is more than 7 times that of the coexisting aqueous vapor e g 0 2 gm cm3 henley and mcnabb 1978 multiple fluids move mix and or unmix in magma chambers and volcanic conduits in the root zone of fumaroles and in the convective hydrothermal systems that are ubiquitous to volcanic environments hydrothermal systems are typically centered on magmatic intrusions and may include crater lakes at the top of eruptive conduits hydrothermal processes involving two or more fluid phases operate through a variety of geologically relevant shallow crustal pressure temperature composition conditions volcanic fluids occur at supersolidus to subsolidus conditions meaning that the dense aluminosilicate melt that is common to volcanism may or may not be present this chapter addresses the evidence for and occurrence of two or more low density aluminosilicate poor fluids

he n and c isotopes and fluxes in aira caldera comparative study of hydrothermal activity in sakurajima volcano and wakamiko crater kyushu japan abstract we investigate the degassing activity of an active submarine crater wakamiko and an active sub aerial volcano sakurajima both located in aira caldera southern kyushu japan we provide 3he 4he 13c co2 and 15n data for 15 hot springs wells and bubbling gas from sakurajima volcano along with 3he 4he from seawater at four different sites for both kagoshima bay and wakamiko crater we find a common magmatic 3he 4he ratio for sakurajima and wakamiko 7 2 0 8 ra which is consistent with 1 a mixing between air saturated water asw and morb type he and 2 a common magmatic source located in the center of aira caldera corrected 3he 4he 13c co2 and ch4 3he data for sakurajima are correlated with the distance from the volcanic vent showa crater which we attribute to crustal contamination and biogenic reaction the low 13c co2 values 10 1 0 2 to 13 7 0 3 observed at sakurajima may result from the addition of carbon from organic matter from basement rocks in magmatic source after correction for air derived nitrogen we find 15nc values range between 1 7 and 4 3 which indicates that magmatic n is dominated by a sedimentary derived component up to 65 8 we calculate wakamiko fluxes of 4he 975 228 mol y 3he 0 011 0 003 mol y co2 184 43 t d and heat 195 22 mw our helium and heat fluxes are the first in situ fluxes ever reported for wakamiko crater all these wakamiko fluxes are at least one order of magnitude lower than those observed for sakurajima co2 1800 t d 3he 0 71 mol y heat 2100 mw degassing at sakurajima volcano is much stronger than that at wakamiko crater the variation of sakurajima co2 flux with time source minamidake or showa crater and eruptive activity appears not to significantly affect the co2 flux at wakamiko crater which is much more stable 132 307 t d during the last 30 years this indicates that there is no link between sakurajima and wakamiko degassing activity despite having the same magmatic source

quantification of the mass flux of h2o gas steam at three active volcanoes using thermal infrared imagery we apply a measurement technique that utilizes thermal video of vapor dominated volcanic plumes to estimate the h2o gas flux at three degassing volcanoes results are compared with h2o flux measurements obtained using other methods to verify the thermal camera derived values our estimation of the h2o emission rate is based on the mass and energy conservation equations h2o flux is quantified by extracting the temperature and width of the gas plume from the thermal images calculating the transit velocity of the gas plume from the thermal video and combining these results with atmospheric parameters measured on site these data are then input into the equations for conservation of mass and energy selected volcanoes for this study were villarrica in chile stromboli in italy and santa ana in el salvador h2o fluxes estimated from the thermal imagery were 38 250 kg s 1 at villarrica 4 5 14 kg s 1 for stromboli s central crater and 168 219 kg s 1 at santa ana these compare with h2o flux values estimated by other methods of 73 220 3 70 and 266 kg s 1 at the three volcanoes respectively the good agreement between thermal image derived results and those estimated by other methods seem to validate this method