estimation of aquifer transmissivity from dar zarrouk parameters in porous media the aim of this paper is to establish an analytical relationship between the aquifer parameters for porous media and the so called dar zarrouk parameters so that the former can best be estimated from the surface resistivity measurements taking the two fundamental laws viz darcy s law of fluid flow and ohm s law of current flow analytical relationships between transmissivity and transverse resistance as well as transmissivity and longitudinal conductance have been established it was found that the relationship between transverse resistance and transmissivity is more meaningful as the product of hydraulic conductivity and electrical conductivity of an aquifer may be assumed to be constant for an area with a particular geological setting and range of water quality this is verified by analysing the data given by kelly

travertine deposits of soda dam new mexico and their implications for the age and evolution of the valles caldera hydrothermal system uranium thorium disequilibrium dates and stable isotope analyses of travertine deposits at soda dam new mexico have been used to determine the age and to document the evolution of the valles caldera hydrothermal system soda dam discharges from paleozoic and precambrian rocks in san diego canyon southwest of the caldera and the canyon was filled with several hundred metres of upper bandelier tuff during formation of valles caldera 1 12 ma according to the dates the valles hydrothermal system is at least 106 yr old or nearly as old as the caldera the basic hydrology of the system has thus remained virtually unchanged during this time travertine ages indicate pulses in travertine deposition from 1 0 to 0 48 ma from 0 107 to 0 058 ma and from 0 005 ma to present the volume of various travertine deposits suggests that the hot spring system at soda dam was once larger than it is today possibly discharging as much as 5 to 10 times more fluid of na hco3 cl composition stable isotopes of the travertines indicate however that the hot spring system has probably never been more than about 10 c hotter than the present maximum temperature of 48 c stable isotopes also show that the 13c of co2 and 18o of h2o in hot spring waters has remained relatively constant for 106 yr the similar ages between caldera formation and the onset of large scale hydrothermal circulation and travertine deposition on pre bandelier tuff rocks imply that incision rates by the jemez river in bandelier tuff were relatively rapid as much as 400 m of tuff were cut by the ancestral jemez river in 105 yr or less

geology of the fenton hill new mexico hot dry rock site abstract the phase i prototype hot dry rock hdr geothermal system was developed in precambrian basement rocks at fenton hill new mexico core and cuttings samples from the four deep wells indicate that the reservoir of this phase i hdr system lies within a homogeneous biotite granodiorite body of very low permeability natural fractures although present are typically sealed with secondary minerals the biotite granodiorite is intrusive into a heterogeneous metamorphic complex comprised of gneisses of variable composition and minor mafic schist amphibolite and metavolcanic rocks the deeper part of this metamorphic section is the site of a deeper phase ii system currently under development differences in geology between the phase i and underlying phase ii systems will provide an opportunity for further testing of hdr development techniques

geochemistry and isotopes of fluids from sulphur springs valles caldera new mexico abstract detailed geochemistry supported by geologic mapping has been used to investigate sulphur springs an acid sulfate hot spring system that issues from the western flank of the resurgent dome inside valles caldera the most intense activity occurs at the intersection of faults offsetting caldera fill deposits and post caldera rhyolites three geothermal wells in the area have encountered pressures 4 8000 mg l these conditions cause argillic alterations throughout a large area non condensible gases consist of roughly 99 co 2 with minor amounts of h 2 s h 2 and ch 4 empirical gas geothermometry suggests a deep reservoir temperature of 215 to 280 c comparison of 13 c and 18 o between caco 3 from well cuttings and co 2 from fumarole steam indicates a fractionation temperature between 200 and 300 c by decarbonation of hydrothermally altered paleozoic limestone and vein calcite in the reservoir rocks tritium concentrations obtained from steam condensed in a mudpot and deep reservoir fluids baca 13 278 c are 2 1 and 1 0 t u respectively suggesting the steam originates from a reservoir whose water is mostly 50 yrs old deuterium contents of fumarole steam deep reservoir fluid and local meteoric water are practically identical even though 18 o contents range through 4 thus precipitation on the resurgent dome of the caldera could recharge the hydrothermal system by slow percolation from analysis of d and 18 o values between fumarol steam and deep reservoir fluid steam reaches the surface either 1 by vaporizing relatively shallow groundwater at 200 c or 2 by means of a two stage boiling process through an intermediate level reservoir at roughly 200 c although many characteristics of known vapor dominated geothermal systems are found at sulphur springs fundamental differences exist in temperature and pressure of our postulated vapor zone we propose that the reservoir beneath sulphur springs is too small or too poorly confined to sustain a true vapor dominated system and that the sulphur springs system may be a dying vapor dominated system that has practically boiled itself dry

monitoring gas and heat emissions at norris geyser basin yellowstone national park usa based on a combined eddy covariance and multi gas approach abstract we quantified gas and heat emissions in an acid sulfate vapor dominated area 0 04 km2 of norris geyser basin located just north of the 0 63 ma yellowstone caldera and near an area of anomalous uplift from 14 may to 3 october 2016 an eddy covariance system measured half hourly co2 h2o and sensible h and latent le heat fluxes and a multi gas instrument measured 1 hz frequency atmospheric h2o co2 and h2s volumetric mixing ratios we also measured soil co2 fluxes using the accumulation chamber method and temperature profiles on a grid and collected fumarole gas samples for geochemical analysis eddy covariance co2 fluxes ranged from 56 to 885 g m 2 d 1 using wavelet analysis average daily eddy covariance co2 fluxes were locally correlated with average daily environmental parameters on several day to monthly time scales estimates of co2 emission rate from the study area ranged from 8 6 t d 1 based on eddy covariance measurements to 9 8 t d 1 based on accumulation chamber measurements eddy covariance water vapor fluxes ranged from 1178 to 24 600 g m 2 d 1 nighttime h and le were considered representative of hydrothermal heat fluxes and ranged from 4 to 183 and 38 to 504 w m 2 respectively the total hydrothermal heat emission rate h le radiant estimated for the study area was 11 6 mw and le contributed 69 of the output the mean standard deviation of h2o co2 and h2s mixing ratios measured by the multi gas system were 9 3 3 1 parts per thousand 467 61 ppmv and 0 5 0 6 ppmv respectively and variations in the gas compositions were strongly correlated with diurnal variations in environmental parameters wind speed and direction atmospheric temperature after removing ambient h2o and co2 the observed variations in the multi gas data could be explained by the mixing of relatively h2o co2 h2s rich fumarole gases with co2 rich and h2o h2s poor soil gases the fumarole h2o co2 and co2 h2s end member ratios 101 7 and 27 1 respectively on average were invariant during the measurement period and fell within the range of values measured in direct fumarole gas samples the soil gas h2o co2 end member ratios 15 30 were variable and low relative to the fumarole end member likely resulting from water vapor loss during cooling and condensation in the shallow subsurface whereas the co2 h2s end member ratio was high 160 presumably related to transport of co2 dominated soil gas emissions mixed with trace fumarolic emissions to the multi gas station nighttime eddy covariance ratios of h2o to co2 flux were typically between the soil gas and fumarole end member h2o co2 ratios defined by multi gas measurements overall the combined eddy covariance and multi gas approach provides a powerful tool for quasi continuous measurements of gas and heat emissions for improved volcano hydrothermal monitoring

mid miocene propagation of the yellowstone mantle plume head beneath the columbia river basalt source region columbia river flood basalt volcanism is the product of mid miocene distortion of the yellowstone mantle plume head against the precambrian margin of north america the overall migration pattern of columbia river basalt vents reflects northward propagation of the plume head beneath the west southwest migrating north american plate thermal uplift mimics the vent migration over the 1 5 m y of grande ronde basalt extrusion the projected crest of the plume head migrated 105 km 7 cm yr from the chief joseph dike swarm east oortheast into the clearwater embayment where uplift occurred over the same period at a rate of 0 67 mm yr chemical variations reflect progressive melting of the plume and mantle lithosphere followed by the mixing of these components with an enriched source from the overriding craton rapid thickening of the plume head against the cratonic margin led to decompressional melting and magma rise beneath a thin oceanic lithosphere of accreted terranes

solute and geothermal flux monitoring using electrical conductivity in the madison firehole and gibbon rivers yellowstone national park abstract the thermal output from the yellowstone magma chamber can be estimated from the cl flux in the major rivers in yellowstone national park and by utilizing continuous discharge and electrical conductivity measurements the cl flux can be calculated the relationship between electrical conductivity and concentrations of cl and other geothermal solutes na so 4 f hco 3 sio 2 k li b and as was quantified at monitoring sites along the madison gibbon and firehole rivers which receive discharge from some of the largest and most active geothermal areas in yellowstone except for some trace elements most solutes behave conservatively and the ratios between geothermal solute concentrations are constant in the madison gibbon and firehole rivers hence dissolved concentrations of cl na so 4 f hco 3 sio 2 k li ca b and as correlate well with conductivity r 2 0 9 for most solutes and most exhibit linear trends the 2011 flux for cl so 4 f and hco 3 determined using automated conductivity sensors and discharge data from nearby usgs gaging stations is in good agreement with those of previous years 1983 1994 and 1997 2008 at each of the monitoring sites continuous conductivity monitoring provides a cost and labor effective alternative to existing protocols whereby flux is estimated through manual collection of numerous water samples and subsequent chemical analysis electrical conductivity data also yield insights into a variety of topics of research interest at yellowstone and elsewhere 1 geyser eruptions are easily identified and the solute flux quantified with conductivity data 2 short term heavy rain events can produce conductivity anomalies due to dissolution of efflorescent salts that are temporarily trapped in and around geyser basins during low flow periods during a major rain event in october 2010 180 000 kg of additional solute was measured in the madison river 3 the output of thermal water from the gibbon river appears to have increased by about 0 2 a in recent years while the output of thermal water for the firehole river shows a decrease of about 10 from 1983 to 2011 confirmation of these trends will require continuing cl flux monitoring over the coming decades

using resistivity measurements for dam safety evaluation at enemossen tailings dam in southern sweden internal erosion is a major reason for embankment dam failures resistivity measurements is an essentially non destructive technique which may have the possibility of detecting internal erosion processes and anomalous seepage at an early stage before the safety of the dam is at stake this paper presents results from part of a dam safety investigation conducted at the enemossen tailings dam in southern sweden longitudinal resistivity sections 2d measurements along the dam crest provided an overview of the whole dam and served to detect anomalous zones in selected areas additional cross sectional 2d surveys gave detailed information about the geo electrical situations in the embankments this information is valuable for similar investigations as information about resistivity in embankment construction material is scarce known problem areas were associated with low resistivities even though the resistivity measurements alone did not provide enough information to confidently come to a decision about the status of the dams

contrasting hydrothermal activity at sierra negra and alcedo volcanoes galapagos archipelago ecuador and approximately 85 so2 of the total sulfur gas relative amounts of he ar and n2 show a distinct hot spot signature the 13c co2 is approximately 3 6 and 34st is approximately 3 3 the d 18o of fumarole h2o indicates steam separation from local meteoric waters whose estimated minimum mean residence time from 3h analyses is 40 years fumarolic activity at alcedo is controlled by a caldera margin fault containing at least seven hydrothermal explosion craters and by an intracaldera rhyolite vent two explosion craters which formed in 1993 1994 produce approximately 15 m3 s of steam yet discharge temperatures are 97 c water content of the total gas is 95 97 mol noncondensible gas is 92 98 mol co2 and sulfur gas is dominated by h2s relative amounts of he ar and n2 show extensive mixing between hot spot and air or air saturated meteoric water components but the average the 13c co2 is approximately 3 5 and 34st is approximately 0 8 the d 18o of fumarole steam indicates separation from a homogeneous reservoir that is enriched 3 5 in 18o compared with local meteoric water 3h indicates that this reservoir water has a maximum mean residence time of approximately 400 years and empirical gas geothermometry indicates a reservoir temperature of 260 320 c the intracaldera hydrothermal reservoir in alcedo is probably capable of producing up to 150 mw however environmental concerns as well as lack of infrastructure and power users will limit the development of this resource

stratigraphic relations and lithologic variations in the jemez volcanic field new mexico over 100 radiometric dates and recent detailed geologic mapping allow some refinements of the stratigraphic relations of major units and generalization of temporal lithologic variations in the jemez volcanic field volcanism had begun in the area by about 16 5 ma with episodic eruptions of alkaline basalts by 13 ma alkaline volcanism had been replaced with eruptions of more voluminous olivine tholeiite high silica rhyolite derived from melts of lower crust also was erupting by about 13 ma basalt and high silica rhyolite continued to be erupted until about 7 and 6 ma respectively but effusions of dominantly andesitic differentiates of basalt that began as early as about 12 ma volumetrically overshadowed all other eruptive products between 10 and 7 ma from 7 to 3 ma the dominant erupted lithology was dacite which appears to have been generated by mixing of magmas whose compositions are approximated by earlier andesites and high silica rhyolites less than 4 3 ma volcanism was dominated by eruption of rhyolitic tuffs field relations geochemistry and dates specifically indicate the following with regards to stratigraphie relations 1 distinctions among basalt of chamisa mesa paliza canyon formation basalts and lobato basalt for other than geographic reasons are artificial basaltic volcanism was continuous in volcanic field from 13 to 7 ma 2 canovas canyon and bearhead rhyolites form a continuum of high silica rhyolite volcanism from 13 to 6 ma 3 hypabyssal and volcanic rocks of the cochiti mining district probably represent the exhumed interior of a keres group volcano s 4 temporal overlaps exist among the major stratigraphie groups which may imply some genetic relations and 5 the tewa group formation cerro rubio quartz latite may more appropriately be considered part of the tschicoma formation of the polvadera group preliminary analysis of hydrothermal alteration in the context of the volcanic stratigraphy suggests at least three distinct hydrothermal events have occurred in the volcanic field s history

noble gas evidence for two fluids in the baca valles caldera geothermal reservoir noble gas elemental and isotopic abundances were measured in steam from four wells in the baca geothermal reservoir located in the valles caldera new mexico the 40ar36ar ratio and noble gas elemental abundances relative to 36ar are all strongly correlated with 1 36ar the inverse of the argon content ratios of n produced 21ne and radiogenic 40ar to total 4he dominantly radiogenic are nearly constant at 2 1 10 8 and 0 20 respectively the 3he4he ratio covers a restricted range of 3 9 to 4 8 times atmospheric the high 3he content of the gas indicates the presence of a helium component ultimately derived from the mantle kr and xe isotopic compositions are close to atmospheric excess 129xe is 0 25 of the total 129xe the high degree of linear correlation among the various noble gas results strongly suggests that the baca reservoir contains two distinct fluids that are produced in varying proportions from individual wells the noble gases in fluid a 2900 mg 1 c1 are air like but with lighter gases and isotopes preferentially enriched the fluid a 36ar content is low only 13 that of 10 c air saturated water asw the second fluid b 1700 mg 1 c1 is the dominant carrier of the radiogenic and mantle derived gases the heavier non radiogenic gases are preferentially enriched in fluid b and its 36ar content is very low only 5 7 asw the source of the noble gases in fluid a is tentatively ascribed to leaching of the relatively young 1 4 m y volcanic bandelier tuff the radiogenic gases and mantle derived helium in fluid b suggest a deeper source possibly including gases escaping from a magma

an interpretation of the alteration assemblages at sulphur springs valles caldera new mexico sulphur springs located near the western edge of the valles caldera north central new mexico is the only vapor dominated surface manifestation of any significance found in the valles the percolating acid sulfate waters and fumarolic gases have leached and oxidized the country rock near the hot springs to a bleached wasteland the near surface mineral assemblages at 90 c are restricted to one and two phases occurring in contact with a variety of solutions and gases the conditions of local equilibrium at 90 g are approximately halotrichite alunogen log fo2 45 log fs2 12 ph 0 3 szomolnokite pyrite log fo2 46 log fs2 16 ph 0 8 alunite log fo2 50 log fs2 10 ph 1 2 kaolinite sulphur log fo2 53 log fs2 10 ph 1 2 log ak 0 0012 m log asio2 0 0033 m and pyrite log fo2 60 log fs2 19 ph 4 3 this study has demonstrated that local equilibrium is closely approached even under the low temperature and pressure conditions found near the surface

annual replenishable ground water potential of india an estimate based on injected tritium studies abstract natural recharge is a vital parameter to be known for ground water budgeting management and modelling percolation of a portion of the rainfall through the vadose zone is the principal source of natural recharge to the aquifer systems in india the tritium injection method based on piston flow model is particularly suitable for quantifying the downward flux of moisture in the vadose zone and for measuring natural recharge in indian climatic condition where about 80 of the annual rainfall is received as pulses and occurs during the four monsoon months from june to september natural recharge measurements using the tritium injection method have been carried out in india during the last 25 years in several basins and watersheds located in varying climatic and hydrogeological situations the mean natural recharge values for 35 study areas well distributed over 17 major river basins are presented the recharge rates range from 24 to 198 mm yr 1 or 4 1 to 19 7 of the local average seasonal rainfall the natural recharge data are grouped into four main hydrogeological provinces namely granitic basaltic sedimentary and alluvial and the regression equations between rainfall and natural recharge are derived for each province these equations enable one to determine the approximate value of natural recharge in any watershed basin from the rainfall data for any year the regression equations are used to compute the total annual replenishment of ground water reserves of the country for an average rainfall year the calculated annual input is about 476 10 9 m 3 yr 1 this can be considered as a minimal quantity as it represents the natural recharge due to precipitation alone and does not account for seepage from ponds lakes stream bed canals and return flow from surface water irrigation

evidence for a new shallow magma intrusion at la soufriere of guadeloupe lesser antilles insights from long term geochemical monitoring of halogen rich hydrothermal fluids more than three decades of geochemical monitoring of hot springs and fumaroles of la soufriere of guadeloupe allows the construction of a working model of the shallow hydrothermal system this system is delimited by the nested caldera structures inherited from the repeated flank collapse events and the present dome built during the last magmatic eruption 1530 ad and which has been highly fractured by the subsequent phreatic or phreatomagmatic eruptions because it is confined into the low volume highly compartmented and partially sealed upper edifice structure the hydrothermal system is highly reactive to perturbations in the volcanic activity input of deep magmatic fluids the edifice structure sealing and fracturing and meteorology wet tropical regime the current unrest which began with a mild reactivation of fumarolic activity in 1990 increased markedly in 1992 with seismic swarms and an increase of degassing from the summit of the dome in 1997 seismic activity increased further and was accompanied by a sudden high flux hcl rich gas from summit fumaroles we focus on the interpretation of the time series of the chemistry and temperature of fumarolic gases and hot springs as well as the relative behaviours of halogens f cl br and i this extensive geochemical time series shows that the deep magmatic fluids have undergone large changes in composition due to condensation and chemical interaction with shallow groundwater scrubbing it is possible to trace back these processes and the potential contribution of a deep magmatic source using a limited set of geochemical time series t co2 and total s content in fumaroles t and cl in hot springs and the relative fractionations between f cl br and i in both fluids coupling 35 years of geochemical data with meteorological rainfall data and models of ion transport in the hydrothermal aquifers has allowed us to identify a series of magmatic gas pulses into the hydrothermal system since the 1976 1977 crisis the contrasting behaviours of s and cl bearing species in fumarolic gas and in thermal springs suggests that the current activity is the result of a new magma intrusion which was progressively emplaced at shallow depth since 1992 although it might still be evolving the characteristics of this new intrusion indicate that it hasalready reached a magnitude similar to the intrusion that was emplaced during the 1976 1977 eruptive crisis the assessment of potential hazards associated with evolution of the current unrest must consider the implications of recurrent intrusion and further pressurization of the hydrothermal system on the likelihood of renewed phreatic explosive activity moreover the role of hydrothermal pressurization on the basal friction along low strength layers within the upper part of the edifice must be evaluated with regards to partial flank collapse at this stage enhanced monitoring research and data analysis is required to quantify the uncertainties related to future scenarios of renewed eruptive activity and magmatic evolution

difference in n2 ar ratio of magmatic gases from northeast and southwest japan new evidence for different states of plate subduction two different plates are subductiog beneath the japanese island arcs the pacific plate in the north and the philippine sea plate in the south geophysical evidence indicates that the philippine sea plate subducts without extending beneath many of the volcanoes in the southwest japan arc the n 2 ar ratio 424 of a common magmatic gas from geothermal and volcanic areas in southwestern japan is an order of magnitude lower than the value 4250 in northeastern japan because the high n 2 ar values reflect input from subducted sediments the large difference in the n 2 ar ratios of magmatic gases indicates that the contribution of subducted sediment to the source of magma in southwestern japan is much lower than that in northeastern japan the n 2 ar ratios off magmatic gases from island arcs elsewhere may also yield information regarding the degree of contribution of subducted sediments to arc magma sources and differences in the states of plate subduction

anomalous chloride flux discharges from yellowstone national park abstract the chloride concentration of some thermal springs in and adjacent to yellowstone national park is constant through time although their discharge varies seasonally as a result the chloride flux from these springs increases during periods of increased discharge we believe that this is caused by changes in the height of the local groundwater table which affects the discharge of the springs but not their chloride concentration the discharge from mammoth hot springs varies seasonally but its chloride concentration remains constant we take this as evidence that this major thermal feature is derived from orifices that are tapping the local water table close to its surface three of the four major rivers yellowstone snake and falls exiting the park also show an increased chloride flux during the spring runoff that cannot be explained solely by the contribution of snowmelt nor by release of hot spring derived chloride stored in the soil during the winter and released in the spring the increased chloride flux in these rivers is attributed to their draining shallow hot springs similar to those mentioned above in contrast to the yellowstone snake and falls rivers the firehole and gibbon rivers which unite to form the madison river and which collectively drain several major geyser basins display a poor correlation between chloride flux and discharge the cause we believe is that a large part of the thermal water input to these two rivers originated at great depths where the seasonal variation in the height of the water table had a negligible effect on hot spring discharge monitoring of seasonal discharge and chloride concentration of thermal features yields information on the depths at which these thermal features tap the local water table

gas geochemistry of the valles caldera region new mexico and comparisons with gases at yellowstone long valley and other geothermal systems abstract noncondensible gases from hot springs fumaroles and deep wells within the valles caldera geothermal system 210 300 c consist of roughly 98 5 mol co 2 0 5 mol h 2 s and 1 mol other components 3 he 4 he ratios indicate a deep magmatic source r r a up to 6 whereas 13 c co 2 values 3 to 5 do not discriminate between a mantle magmatic source and a source from subjacent hydrothermally altered paleozoic carbonate rocks regional gases from sites within a 50 km radius beyond valles caldera are relatively enriched in co 2 and he but depleted in h 2 s compared to valles gases regional gases have r r a values 1 2 due to more interaction with the crust and or less contribution from the mantle carbon sources for regional co 2 are varied during 1982 1998 repeat analyses of gases from intracaldera sites at sulphur springs showed relatively constant ch 4 h 2 and h 2 s contents the only exception was gas from footbath spring 1987 1993 which experienced increases in these three components during drilling and testing of scientific wells vc 2a and vc 2b present day valles gases contain substantially less n 2 than fluid inclusion gases trapped in deep early stage post caldera vein minerals this suggests that the long lived valles hydrothermal system ca 1 myr has depleted subsurface paleozoic sedimentary rocks of nitrogen when compared with gases from many other geothermal systems valles caldera gases are relatively enriched in he but depleted in ch 4 n 2 and ar in this respect valles gases resemble end member hydrothermal and magmatic gases discharged at hot spots galapagos kilauea and yellowstone

geothermal solute flux monitoring and the source and fate of solutes in the snake river yellowstone national park wy abstract the combined geothermal discharge from over 10 000 features in yellowstone national park ynp can be can be estimated from the cl flux in the madison yellowstone falls and snake rivers over the last 30 years the cl flux in ynp rivers has been calculated using discharge measurements and cl concentrations determined in discrete water samples and it has been determined that approximately 12 of the cl flux exiting ynp is from the snake river the relationship between electrical conductivity and concentrations of cl and other geothermal solutes was quantified at a monitoring site located downstream from the thermal inputs in the snake river beginning in 2012 continuous 15 min electrical conductivity measurements have been made at the monitoring site combining continuous electrical conductivity and discharge data the cl and other geothermal solute fluxes were determined the 2013 2015 cl fluxes 5 3 5 8 kt yr determined using electrical conductivity are comparable to historical data in addition synoptic water samples and discharge data were obtained from sites along the snake river under low flow conditions of september 2014 the synoptic water study extended 17 km upstream from the monitoring site surface inflows were sampled to identify sources and to quantify solute loading the lewis river was the primary source of cl na k cl sio2 rb and as loads 50 80 in the snake river the largest source of so4 was from the upper snake river 50 most of the ca and mg 50 55 originate from the snake hot springs chloride ca mg na k sio2 f hco3 so4 b li rb and as behave conservatively in the snake river and therefore correlate well with conductivity r2 0 97

estimating aquifer recharge and parameters from water level observations this paper is concerned with the development of a technique to estimate recharge from rainfall and to estimate aquifer parameters using groundwater level records and available climatological data the methodology combines a hydrometeorological model which links rainfall and evapotranspiration to the effective groundwater recharge and a geohydrologic model which links the recharge to the water level in the aquifer results of field application are presented to illustrate the usefulness of the technique

analysis of hot springs and associated deposits in yellowstone national park using aster and aviris remote sensing the advanced spaceborne thermal emission and reflection radiometer aster and the airborne visible ir image spectrometer aviris data were used to characterize hot spring deposits in the lower midway and upper geyser basins of yellowstone national park from the visible near infrared vnir to thermal infrared tir wavelengths field observations of these basins provided the critical ground truth for comparison with the remote sensing results fourteen study sites were selected based on diversity in size deposit type and thermal activity field work included detailed site surveys such as land cover analysis photography global positioning system gps data collection radiometric analysis and vnir spectroscopy samples of hot spring deposits geyser deposits and soil were also collected analysis of aster data provided broad scale characteristics of the hot springs and their deposits including the identification of thermal anomalies aviris high spectral resolution short wave infrared swir spectroscopy provided the ability to detect hydrothermally altered minerals as well as a calibration for the multispectral swir aster data from the image analysis differences in these basins were identified including the extent of thermal alteration the location and abundance of alteration minerals and a comparison of active near extinct and extinct geysers we determined the activity level of each region using a combination of the vnir swir tir spectral differences as well as the presence of elevated temperatures detected by the tir subsystem of aster the results of this study are applicable to the exploration of extinct mineralized hydrothermal deposits on both earth and mars

estimation of natural recharge and its dependency on sub surface geoelectric parameters abstract natural groundwater recharge is estimated using the injected tracer technique in the bairasagara watershed of kolar district karnataka india comprising of medium grained granite and granitic gneiss with weathering fracturing up to 46 m depth on a macroscopic scale it is estimated that the weathered granites act as a uniform body having a recharge capacity of about 6 200 mm per annum for an average value of rainfall of 968 mm marked differences of infiltration rates nil to 130 cm year were observed under cultivated and dry areas the water level fluctuation and recharge are found to be minimum in the ayacut area as compared to the catchment area studies helped in demarcating recharge and discharge areas qualitative correlation studies of estimated natural groundwater recharge have been carried out with depth to basement resistivity of subsurface layers and water level fluctuations an attempt has been made to get empirical relationships between recharge vs depth to basement and recharge vs water level fluctuations the paper discusses the studies carried out the result obtained and the importance of such studies in the evaluation of groundwater resources

chloride flux out of yellowstone national park abstract monitoring of the chloride concentration electrical conductivity and discharge was carried out for the four major rivers of yellowstone national park from september 1982 to january 1984 chloride flux out of the park was determined from the measured values of chloride concentration and discharge the annual chloride flux from the park was 5 86 1010 g of this amount 45 was from the madison river drainage basin 32 from the yellowstone river basin 12 from the snake river basin and 11 from the falls river basin of the annual chloride flux from the yellowstone river drainage basin 36 was attributed to the yellowstone lake drainage basin the geothermal contribution to the chloride flux was determined by subtracting the chloride contribution from rock weathering and atmospheric precipitation and is 94 of the total chloride flux calculations of the geothermal chloride flux for each river are given and the implications of an additional chloride flux out of the western park boundary discussed an anomalous increase in chloride flux out of the park was observed for several weeks prior to the mt borah earthquake in central idaho on october 28 1983 reaching a peak value shortly thereafter it is suggested that the rise in flux was a precursor of the earthquake the information in this paper provides baseline data against which future changes in the hydrothermal systems can be measured it also provides measurements related to the thermal contributions from the different drainage basins of the park

tree ring 14c links seismic swarm to co2 spike at yellowstone usa mechanisms to explain swarms of shallow seismicity and inflation deflation cycles at yellowstone caldera western united states commonly invoke episodic escape of magma derived brines or gases from the ductile zone but no correlative changes in the surface efflux of magmatic constituents have ever been documented our analysis of individual growth rings in a tree core from the mud volcano thermal area within the caldera links a sharp 25 drop in 14 c to a local seismic swarm in 1978 the implied fivefold increase in co 2 emissions clearly associates swarm seismicity with upflow of magma derived fluid and shows that pulses of magmatic co 2 can rapidly traverse the 5 km thick brittle zone even through yellowstone9s enormous hydrothermal reservoir the 1978 event predates annual deformation surveys but recognized connections between subsequent seismic swarms and changes in deformation suggest that co 2 might drive both processes

temporal variations of geyser water chemistry in the upper geyser basin yellowstone national park usa 1 geysers are rare features that reflect a delicate balance between an abundant supply of water and heat and a unique geometry of fractures and porous rocks between april 2007 and september 2008 we sampled old faithful daisy grand oblong and aurum geysers in yellowstone national park s upper geyser basin and characterized temporal variations in major element chemistry and water isotopes 18o d 3h we compare these temporal variations with temporal trends of geyser eruption intervals gei sio2 concentrations and geothermometry indicate that the geysers are fed by waters ascending from a reservoir with temperatures of 190 to 210 c the studied geysers display small and complex chemical and isotopic seasonal variations and geysers with smaller volume display larger seasonal variations than geysers with larger volumes aurum and oblong geysers contain detectable tritium concentrations suggesting that erupted water contains some modern meteoric water we propose that seasonal gei variations result from varying degrees of evaporation meteoric water recharge water table fluctuations and possible hydraulic interaction with the adjacent firehole river we demonstrate that the concentrations of major dissolved species in old faithful geyser have remained nearly constant since 1884 despite large changes in old faithful s eruption intervals suggesting that no major changes have occurred in the hydrothermal system of the upper geyser basin for 120 years our data set provides a baseline for monitoring future changes in geyser activity that might result from varying climate earthquakes and changes in heat flow from the underlying magmatic system

geology of the platanares geothermal area departamento de copan honduras abstract the platanares geothermal area departamento de copan honduras is located within a graben that is complexly faulted the graben is bounded on the north by a highland composed of paleozoic metamorphic rocks in contact with cretaceous tertiary redbeds of unknown thickness these are unconformably overlain by tertiary andesitic lavas rhyolitic ignimbrites and associated sedimentary rocks the volcanic rocks are mostly older than 14 ma and thus are too old to represent the surface expression of an active crustal magma body thermal fluids that discharge in the area are heated during deep circulation of meteoric water along faults in a region of somewhat elevated heat flow geothermometry based upon the chemical composition of thermal fluids from hot springs and from geothermal gradient coreholes suggests that the reservoir equilibrated at temperatures as high as 225 to 240 c within the cretaceous redbed sequence three continuously cored geothermal gradient holes have been drilled fluids of about 165 c have been produced from two drilled along a nw trending fault zone from depths of 250 to 680 m a conductive thermal gradient of 139 c km at a depth of 400 m was determined from the third well drilled 0 6 km west of that fault zone these data indicate that the platanares geothermal area holds considerable promise for electrical generation by moderate to hightemperature geothermal fluids

k ar dates of hydrothermal clays from core hole vc 2b valles caldera new mexico and their relation to alteration in a large hydrothermal system abstract seventeen k ar dates were obtained on illitic clays within valles caldera 1 13 ma to investigate the impact of hydrothermal alteration on quaternary to precambrian intracaldera and pre caldera rocks in a large long lived hydrothermal system 1 0 ma to present clay samples came from scientific core hole vc 2b 295 c at 1762 m which was spudded in the sulphur springs thermal area and drilled into the boundary between the central resurgent dome and the western ring fracture zone six illitic clays within quaternary caldera fill debris flow tuffaceous sediment and ash flow tuff 48 to 587 m depth yield ages from 0 35 to 1 09 ma illite from miocene pre caldera sandstone 765 m gives an age of 6 74 ma two dates on illite from sandstones in permian red beds 1008 and 1187 m are 4 33 and 4 07 ma respectively surprisingly three dates on illites from altered andesite pebbles within the red beds 1010 1014 m are 0 95 to 1 06 ma four illite dates on variably altered precambrian quartz monzonite 1615 1762 m range from 2 90 to 276 ma post valles age illite is not correlated with alteration style argillic to propylitic rather post valles ages are uniformly obtained from illites in highly fractured intensely altered caldera fill rocks and the permian volcanic clasts generally finer clay fractions from identical samples yield younger ages plots of 40 ar 36 ar versus 40 k 36 ar and 40 ar versus 40 k for the illites in caldera fill rocks lie close to a 1 ma isochron most illite dates older than valles caldera are difficult to interpret because they correspond to the ages of pre valles volcanic and hydrothermal episodes in the jemez volcanic field 13 ma in addition older dates may be caused by co mingling of different illites during sample preparation or by inherited argon or lost argon in illites from rocks with potentially complex hydrothermal histories however the range of ages obtained from illites in permian sands and pebbles and from precambrian crystalline rocks indicates that valles hydrothermal activity is overwhelming illite produced by earlier geologic events

noble gases from honduras geothermal sites the elemental and isotopic composition of noble gases in hot springs and geothermal test wells were determined as part of a collaborative project to evaluate the potential for geothermal development in honduras central america the relative abundances of the noble gases in samples from the test wells indicate recharge temperatures for the geothermal systems equivalent to mean annual temperatures a common ratio of radiogenic 40ar to 4he of 0 35 corresponding to a k u ratio of 2 104 was found in samples from three of the studied areas platanares azacualpa and san ignacio a constant ratio may imply a common reservoir rock possibly the valle de angeles group of cretaceous to eocene age 3he 4he ratios are correlated in a positive sense with so4 concentration and in a negative sense with geothermal reservoir temperatures determined from chemical geothermometers these correlations are best explained by dilution of primary geothermal fluids with cooler sulfate rich waters the cooler waters inhibit deep boiling preserving high 3he 4he ratios in the surface springs in the el olivar region either the cool diluting fluid is sulfate poor or there is additional excess 3he provided by nearby quaternary trachytic to basaltic volcanism of the southern yojoa graben

the slope movements within the mondores graben drome france the interaction between geology hydrology and typology the mondores graben in the south eastern french alps is an uncommon structural feature which originates in a complex polyphasic tectonic evolution in contrast with its immediate surroundings with hardly any huge landslides the mondores graben is characterised by various types of landslides a huge sagging caused part of the limestone cliff to subside some 50 m within 50 years two recent mud flows that occurred were considered a potential threat to some inhabited places downstream the hydrologic aspects of the boulc mondores landslide resemble the geology infiltration and karst input in the rock sliding zone and exfiltration in the marls resulting in slumps and mud flows the mass movement interactions could be explained by a structural geology analysis with geodetic monitoring using different techniques it is also shown that hydrochemistry as well as geophysical surveys are of importance in unravelling the hydrologic systems and the geological subsurface structures the present paper aims at explaining the geological control of the different slides in view of estimating their potential danger understanding the geological structure and its evolution therefore is a necessary prerequisite

volatile emissions and gas geochemistry of hot spring basin yellowstone national park usa abstract we characterize and quantify volatile emissions at hot spring basin hsb a large acid sulfate region that lies just outside the northeastern edge of the 640 ka yellowstone caldera relative to other thermal areas in yellowstone hsb gases are rich in he and h2 and mildly enriched in ch4 and h2s gas compositions are consistent with boiling directly off a deep geothermal liquid at depth as it migrates toward the surface this fluid and the gases evolved from it carries geochemical signatures of magmatic volatiles and water rock reactions with multiple crustal sources including limestones or quartz rich sediments with low k u or 40 ar 4 he variations in gas chemistry across the region reflect reservoir heterogeneity and variable degrees of boiling gas geothermometer temperatures approach 300 c and suggest that the reservoir feeding hsb is one of the hottest at yellowstone diffuse co2 flux in the western basin of hsb as measured by accumulation chamber methods is similar in magnitude to other acid sulfate areas of yellowstone and is well correlated to shallow soil temperatures the extrapolation of diffuse co2 fluxes across all the thermal altered area suggests that 410 140 t d 1 co2 are emitted at hsb vent emissions not included diffuse fluxes of h2s were measured in yellowstone for the first time and likely exceed 2 4 t d 1 at hsb comparing estimates of the total estimated diffuse h2s emission to the amount of sulfur as so42 in streams indicates 50 of the original h2s in the gas emission is lost into shallow groundwater precipitated as native sulfur or vented through fumaroles we estimate the heat output of hsb as 140 370 mw using co2 as a tracer for steam condensate but not including the contribution from fumaroles and hydrothermal vents overall the diffuse heat and volatile fluxes of hsb are as great as some active volcanoes but they are a small fraction 1 3 for co2 2 8 for heat of that estimated for the entire yellowstone system

a sr isotopic comparison between thermal waters rocks and hydrothermal calcites long valley caldera california abstract the 87 sr 86 sr values of thermal waters and hydrothermal calcites of the long valley caldera geothermal system are more radiogenic than those of young intracaldera volcanic rocks five thermal waters display 87 sr 86 sr of 0 7081 0 7078 but show systematically lighter values from west to east in the direction of lateral flow we believe the decrease in ratio from west to east signifies increased interaction of deeply circulating thermal water with relatively fresh volcanic rocks filling the caldera depression all types of pre syn and post caldera volcanic rocks in the west and central caldera have 87 sr 86 sr m between about 0 7060 and 0 7072 and values for sierra nevada granodiorites adjacent to the caldera are similar sierran pre intrusive metavolcanic and metasedimentary rocks can have considerably higher sr isotope ratios 0 7061 0 7246 and 0 7090 0 7250 respectively hydrothermally altered volcanic rocks inside the caldera have 87 sr 86 sr m slightly heavier than their fresh volcanic equivalents and hydrothermal calcites 0 7068 0 7105 occupy a midrange of values between the volcanic plutonic rocks and the sierran metamorphic rocks these data indicate that the long valley geothermal reservoir is first equilibrated in a basement complex that contains at least some metasedimentary rocks reequilibration of sr isotope ratios to lower values occurs in thermal waters as convecting geothermal fluids flow through the isotopically lighter volcanic rocks of the caldera fill

tectonics of the jemez lineament in the jemez mountains and rio grande rift the jemez lineament is a ne trending crustal flaw that controlled volcanism and tectonism in the jemez mountains and the rio grande rift zone the fault system associated with the lineament in the rift zone includes from west to east the jemez fault zone southwest of the valles toledo caldera complex a series of ne trending faults on the resurgent dome in the valles caldera a structural discontinuity with a high fracture intensity in the ne jemez mountains and the embudo fault zone in the espanola basin the active western boundary faulting of the espanola basin may have been restricted to the south side of the lineament since the mid miocene the faulting apparently began on the sierrita fault on the east side of the nacimiento mountains in the late oligocene and stepped eastward in the early miocene to the canada de cochiti fault zone at the end of the miocene about 5 ma the active boundary faulting again stepped eastward to the pajarito fault zone on the east side of the jemez mountains the north end of the pajarito fault terminates against the jemez lineament at a point where it changes from a structural discontinuity zone of high fracture intensity on the west to the embudo fault zone on the east major transcurrent movement occurred on the embudo fault zone during the pliocene and has continued at a much slower rate since then the relative sense of displacement changes from right slip on the western part of the fault zone to left slip on the east the kinematics of this faulting probably reflect the combined effects of faster spreading in the espanola basin than the area north of the lineament abiquiu embayment and san luis basin the right step in the rift that juxtaposes the san luis basin against the picuris mountains and counterclockwise rotation of various crustal blocks within the rift zone no strike slip displacements have occurred on the lineament in the central and eastern jemez mountains since at least the mid miocene although movements on the still active jemez fault zone in the western jemez mountains may have a significant strike slip component basaltic volcanism was occurring in the jemez mountains at four discrete vent areas on the lineament between about 15 ma and 10 ma and possibly as late as 7 ma indicating that it was being extended during that time

n2 ar he compositions in fluid inclusions indicators of fluid source abstract a quadrupole mass spectrometer was used to measure bulk samples of conservative gas species n 2 ar and he in fluid inclusions from a variety of hydrothermal systems analyses of these tracer elements help determine 1 1 if gases extracted by bulk inclusion analyses can provide accurate measurement of n 2 ar he in active and fossil geothermal systems 2 2 if hydrothermal fluids associated with paleogeothermal systems in a continental setting follow n 2 ar he systematics similar to th the western pacific rim active geothermal systems specifically new zealand and 3 3 whether different deposit types systematically vary with regard to n 2 ar he the n 2 ar he ratios of fluid inclusion volatiles released from recently deposited minerals from the valles system are similar to those of present day valles thermal waters those inclusion samples from deep within the valles system below a regional aquitard increase in n 2 compositions for inclusions from the questa and copper flat porphyry deposits are n 2 rich similar to those of arc related volcanic gases whereas those from taylor creek sn deposit appear to be mixtures of magmatic and crustal components n 2 ar he ratios of the precambrian tribag deposit suggest a basalt source but significant levels of self generated he from u and th in the inclusion fluids are also possible inclusions from two epithermal deposits with low salinity inclusions have n 2 ar he ratios trending towards air saturated meteoric waters asw and those inclusions with higher salinities indicate minor to no asw component the n 2 ar he ratios in fresnillo and cochiti inclusions which have magmatic helium isotopic ratios indicate additions of magmatic gases to meteoric fluids inclusions from sediment hosted deposits that contain hydrocarbon bearing brines are he rich as are meteoric waters with a long residence time in the crust at relevant pressure temperature composition conditions henry s law constants of n 2 ar and he are similar and thus the relative amounts of these species trapped under boiling conditions will not vary appreciably from solubility controlled amounts in coexisting liquid furthermore there is no evidence of he loss or gain in inclusions by diffusion process data from the various systems that were examined indicate that fluid inclusion n 2 ar he compositions may be related to magmatic fluid sedimentary brine deep circulating meteoric fluid and shallow circulating meteoric fluid sources which we modified from those proposed by giggenbach 1986 relationships between the n 2 ar he tracer gases and other measurable quantities in fluid inclusions are indicated to be helpful in understanding fluid mixing processes in paleogeothermal systems

source and fate of inorganic solutes in the gibbon river yellowstone national park wyoming usa i low flow discharge and major solute chemistry abstract the gibbon river in yellowstone national park ynp is an important natural resource and habitat for fisheries and wildlife however the gibbon river differs from most other mountain rivers because its chemistry is affected by several geothermal sources including norris geyser basin chocolate pots gibbon geyser basin beryl spring and terrace spring norris geyser basin is one of the most dynamic geothermal areas in ynp and the water discharging from norris is much more acidic ph 3 than other geothermal basins in the upper madison drainage gibbon and firehole rivers water samples and discharge data were obtained from the gibbon river and its major tributaries near norris geyser basin under the low flow conditions of september 2006 surface inflows from norris geyser basin were sampled to identify point sources and to quantify solute loading to the gibbon river the source and fate of the major solutes ca mg na k sio 2 cl f hco 3 so 4 no 3 and nh 4 in the gibbon river were determined in this study and these results may provide an important link in understanding the health of the ecosystem and the behavior of many trace solutes norris geyser basin is the primary source of na k cl so 4 and n loads 35 58 in the gibbon river the largest source of hco 3 and f is in the lower gibbon river reach most of the ca and mg originate in the gibbon river upstream from norris geyser basin all the major solutes behave conservatively except for nh 4 which decreased substantially downstream from gibbon geyser basin and sio 2 small amounts of which precipitated on mixing of thermal drainage with the river as much as 9 14 of the river discharge at the gage is from thermal flows during this period

comparison of hydrothermal alteration of carboniferous carbonate and siliclastic rocks in the valles caldera with outcrops from the socorro caldera new mexico abstract continental scientific drilling program csdp drill hole vc 2b total depth 1761 7 m 5780 ft maximum temperature 295 c was continuously cored through the sulphur springs hydrothermal system in the western ring fracture zone of the 1 14 ma valles caldera among other units the hole penetrated 760 2 m 2494 1 ft of paleozoic carbonate and siliciclastic strata underlying caldera fill and precaldera volcanic and epiclastic rocks comparison of the vc 2b paleozoic rocks with corresponding lithologies within and around the 32 1 ma socorro caldera 192 km 119 miles to the south southwest provides insight into the variability of alteration responses to similar caldera related hydrothermal regimes the pennsylvanian madera limestone and sandia formation from vc 2b preserve many of the sedimentological and diagenetic features observed in these units on a regional basis and where unaffected by high temperatures or hydrothermal activity micrites in these formations in vc 2b are generally altered and mineralized only where fractured or brecciated that is where hydrothermal solutions could invade carbonate rocks which were otherwise essentially impermeable alteration intensity and correspondingly inferred paleopermeability is only slightly higher in carbonate packstones and grainstones low to intermediate in siltstones and claystones and high in poorly cemented sandstones hydrothermal fracture filling phases in these rocks comprise sericite and phengite chlorite allanite apatite an unidentified zeolite and sphene in various combinations locally with sphalerite galena pyrite and chalcopyrite terrigenous feldspars and clays are commonly altered to chlorite and seriate and euhedral anhydrite porphyroblasts with minor chlorite occur in sandia formation siltstone fossils are typically unaltered but the walls of some colonial bryozoans in the madera limestone are altered to the assemblage chlorite sericite epidote allanite la ce and nd are present in an unidentified hydrothermal mineral occurring throughout much of the vc 2b pennsylvanian sequence carboniferous carbonate and siliciclastic formations within and around the socorro caldera show a similar style of alteration and mineralization to their valles caldera counterparts but by contrast locally host commercial caldera related base metal sulfide deposits as in the valles rocks mineralization and alteration in those of the socorro caldera were strongly controlled by porosity unless disrupted by fractures breccias or karst cavities not identified in valles caldera drill holes the rocks remained relatively unaltered where these features allowed ingress of mineralizing hydrothermal solutions base metal sulfides and rare earth element bearing minerals were precipitated

p and s velocity structure of the yellowstone volcanic field from local earthquake and controlled source tomography the three dimensional p and s velocity from vp vs ratios distribution and improved hypocenters for the yellowstone volcanic field have been determined from inversion of first arrival times from 7942 local earthquakes and 16 controlled source explosions the p velocity model has an rms residual of 0 09 s whereas the vp vs ratio model calculated from 511 earthquakes has an rms residual of 0 29 s high p and s velocities outside the yellowstone caldera represent thermally undisturbed basement and sedimentary rocks a caldera wide 15 decrease from regional p velocities at depths of 6 to 12 km is coincident with a 60 mgal gravity anomaly and is interpreted as a hot subsolidus granitic batholith with a quasi plastic rheology localized 30 reductions from regional seismic velocities and higher vp vs ratios 8 km beneath yellowstone s resurgent domes are interpreted as partial melts and vestigial magma systems associated with youthful less than 2 ma silicic volcanism additional low seismic velocities and vp vs ratios and a 20 mgal gravity low less than 4 km beneath the northeast caldera rim are interpreted as a hydrothermal fracture zone thermally driven by underlying partial melt hypocenters relocated with the three dimensional p velocity model show subparallel alignment with nw se trending postcaldera volcanic vents and normal faults northwest of the caldera focal depths of relocated earthquakes decrease from more than 11 km outside the caldera to less than 6 km within the caldera reflecting thinning and heating of the seismogenic crust

remediation and analysis of kinematic behaviour of a roadway landslide in the upper minjiang river southwest china because of terrain geological structure river down incising and human activities the upriver minjiang valley in sichuan province southwest china constitutes a disaster area prone to frequent landslides during the roadway rebuilding periods the xiaozongqu landslide reactivated on the g213 roadway in maoxian district of sichuan province from the september to november in 2002 the landslide sped up reaching a maximum movement rate of 32 mm d the rapid slide seriously threatened the road to stabilize the landslide and eliminate the damage of landslide to the road remedying its damage and monitoring further developments are crucial based on its kinematic behaviour remediation was implemented in two phases from november 2002 to october 2003 systematic monitoring has been carried out since 18 june 2003 to determine kinematic variations of the landslide during the post remediation period and to assess the effects of remediation and the potential of the landslide for further destructive influences on the roadway

characteristics and remediation of a landslide complex triggered by the 2008 wenchuan china earthquake case from yingxiu near the earthquake epicenter during the 2008 wenchuan earthquake the river valley from yingxiu to wenchuan experienced numerous landslides and became a prominent area of landslide complexes the present large landslide complex near the earthquake epicenter consisted of laohuzui slide 1 laohuzui slide 2 and douyaping slide the scale geology morphology sliding process and failure mechanism of the landslide complex are analyzed by means of field investigation aerial photograph and stereographic projection technique characteristics of these three slides including seismic response of slope landslide debris damage and potential failure are discussed the convex slope and the upslope of fractured granitic rock at high altitude are highly prone to landsliding under earthquake the high source altitude and long travel path determine grain sizes and the deposit angle of the slide debris the landslide complex completely buries the g213 roadway and dams up the minjiang river in these sections after the earthquake rainfall aftershocks and river erosion may retrigger new failures such as retrogressive slide of weathered fractured rock colluvial landslide debris flow embankment failure and rockfall the following are presented as suggested remedial measures to protect the roadway and stabilize the slope the removing and trenching protective concrete rock blocks against erosion retaining structure rockfall stopping wall rockfall restraining net rock bolt and the planting of vegetation

monitoring super volcanoes geophysical and geochemical signals at yellowstone and other large caldera systems earth s largest calderas form as the ground collapses during immense volcanic eruptions when hundreds to thousands of cubic kilometres of magma are explosively withdrawn from the earth s crust over a period of days to weeks continuing long after such great eruptions the resulting calderas often exhibit pronounced unrest with frequent earthquakes alternating uplift and subsidence of the ground and considerable heat and mass flux because many active and extinct calderas show evidence for repetition of large eruptions such systems demand detailed scientific study and monitoring two calderas in north america yellowstone wyoming and long valley california are in areas of youthful tectonic complexity scientists strive to understand the signals generated when tectonic volcanic and hydrothermal hot ground water processes intersect one obstacle to accurate forecasting of large volcanic events is humanity s lack of familiarity with the signals leading up to the largest class of volcanic eruptions accordingly it may be difficult to recognize the difference between smaller and larger eruptions to prepare ourselves and society scientists must scrutinize a spectrum of volcanic signals and assess the many factors contributing to unrest and toward diverse modes of eruption

heat flow in vapor dominated areas of the yellowstone plateau volcanic field implications for the thermal budget of the yellowstone caldera the yellowstone caldera the 0 11 km 2 obsidian pool thermal area opta and the 0 25 km 2 solfatara plateau thermal area spta conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at 600 locations and from laboratory measurements of soil properties the conductive heat output is 3 6 0 4 mw and 7 5 0 4 mw from the opta and the spta respectively the advective heat output from soils is 1 3 0 3 mw and 1 2 0 3 mw from the opta and the spta respectively and the heat output from thermal pools in the opta is 6 8 1 4 mw these estimates result in a total heat output of 11 8 1 4 mw and 8 8 0 4 mw from opta and spta respectively focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor

extracting geothermal energy can be hard the initially high expectations of the mid 1970 s for the rapid development of geothermal energy have been lowered one reason is continuing uncertainty about the extraction of geothermal energy drillers can have a good idea of which areas have concentrations of geothermal energy beneath the surface and still have trouble bringing up enough energy to make a power plant worthwhile the extraction problem has been highlighted by the recent termination of a federal geothermal demonstration project at the baca field of the valles caldera new mexico the sixth largest geothermal province in the united states the problem at baca is not necessarily insoluble but it is tending to accentuate industry s cautious approach to geothermal exploration

a generalized 3 d geological and hydrogeological conceptual model of granite aquifers controlled by single or multiphase weathering summary the weathered layers of crystalline rocks form aquifers that are of prime interest for water supply in hard rock areas these weathering profiles generally develop under both stable geodynamic conditions weathering rate erosion rate and a hydrolysing climate they are composed of thick stratiform layers that follow the paleo landscape paleotopography and thus present a gently dipping sequence at a regional scale the structure and the hydrodynamic properties of the weathering profile of a granitic area 53 km 2 maheshwaram catchment state of andhra pradesh india were characterized in detail and mapped from observations on outcrops 80 vertical electric soundings and lithologs from 45 borewells in which flowmeter measurements and injection tests were also performed to characterize the hydraulic conductivities of the conductive fissure zones the structure of the weathering profile results from a multiphase process an ancient weathering profile was partly eroded down to its fissured layer it was later re weathered more or less parallel to the current topographic surface this peculiar structure is linked to the geodynamic history of the indian peninsula that underwent alternate weathering and erosion dominated phases the profile is thus composed from top to bottom up to a total depth of 35 m of sandy regolith saprolite 1 3 m 10 15 m of laminated saprolite containing unusual preserved fissures and a 15 20 m thick fissured layer by comparing various case studies in similar terrain a generalized 3 d geological and hydrogeological conceptual model of granite type aquifers granites gneisses etc is proposed in granite type rocks single weathering or multiphase weathering and erosion processes induce similar geological structures a few main geological differences arise from the comparison of single phase and multiphase weathering profiles i in the later the respective thicknesses of the various layers can be deeply modified ii the ancient fissured layer can be re weathered and the resulting new laminated layer may contain quite well preserved and conductive ancient fissures and iii the upper part of the fissured layer is more densely fissured as a result of the same weathering processes the fissures from the fissured layer of single phase or multi phase profiles exhibit very similar hydraulic conductivities and show both a higher density of conductive fissures at the top of the layer the preserved ancient fissures within the laminated layer of a multiphase profile are partly obliterated by the recent weathering their hydraulic conductivity is thus significantly reduced nevertheless they do significantly contribute to borewell yield these weathering induced fissures provide most of the aquifer permeability the use of such a conceptual model for the precise geological mapping of the weathering structure appears to be a prerequisite for groundwater development and management in hard rock areas as it answers to several key issues

radiocarbon dating of silica sinter deposits in shallow drill cores from the upper geyser basin yellowstone national park abstract to explore the timing of hydrothermal activity at the upper geyser basin ugb in yellowstone national park we obtained seven new accelerator mass spectrometry ams radiocarbon 14 c ages of carbonaceous material trapped within siliceous sinter five samples came from depths of 15 152 cm within the y 1 well and two samples were from well y 7 depths of 24 cm and 122 cm these two wells at black sand and biscuit basins respectively were drilled in 1967 as part of a scientific drilling program by the u s geological survey white et al 1975 even with samples as small as 15 g we obtained sufficient carbonaceous material a mixture of thermophilic mats pollen and charcoal for the 14 c analyses apparent time of deposition ranged from 3775 25 and 2910 30 14 c years bp at the top of the cores to about 8000 years bp at the bottom the dates are consistent with variable rates of sinter formation at individual sites within the ugb over the holocene on a basin wide scale though these and other existing 14 c dates hint that hydrothermal activity at the ugb may have been continuous throughout the holocene

generation and evolution of hydrothermal fluids at yellowstone insights from the heart lake geyser basin 1 we sampled fumaroles and hot springs from the heart lake geyser basin hlgb measured water and gas discharge and estimated heat and mass flux from this geothermal area in 2009 the combined data set reveals that diverse fluids share an origin by mixing of deep solute rich parent water with dilute heated meteoric water accompanied by subsequent boiling a variety of chemical and isotopic geothermometers are consistent with a parent water that equilibrates with rocks at 205 c 10 c and then undergoes 21 2 adiabatic boiling measured diffuse co2 flux and fumarole compositions are consistent with an initial dissolved co2 concentration of 21 7 mmol upon arrival at the caldera boundary and prior to southeast flow boiling and discharge along the witch creek drainage the calculated advective flow from the basin is 78 16 l s 1of parent thermal water corresponding to 68 14 mw or 1 of the estimated thermal flux from yellowstone helium and carbon isotopes reveal minor addition of locally derived crustal biogenic and meteoric gases as this fluid boils and degasses reducing the he isotope ratio rc ra from 2 91 to 1 09 the hlgb is one of the few thermal areas at yellowstone that approaches a closed system where a series of progressively boiled waters can be sampled along with related steam and noncondensable gas at other yellowstone locations steam and gas are found without associated neutral cl waters e g hot spring basin or cl rich waters emerge without significant associated steam and gas upper geyser basin

estimation of hard rock aquifers hydraulic conductivity from geoelectrical measurements a theoretical development with field application summary based on the analogy between darcy s law for groundwater flow and ohm s law for electric current flow a methodology has been developed to estimate the hydraulic conductivity and transmissivity of hard rock granite aquifer from geoelectrical parameters the common parameter aquifer thickness t has been used to combine the two relations and form an analytical equation mathematical relation shows a negative correlation between hydraulic conductivity and aquifer resistivity and a positive correlation between transmissivity and longitudinal conductance the methodology has been calibrated and validated in hard rock granite aquifers in india the good agreement between aquifer hydraulic conductivity k and transmissivity t obtained from the resistivity sounding parameters and those obtained from pumping test analysis proves the potentiality of the methodology it has been applied to estimate the k and t from the surface electrical resistivity parameters and results were utilized to prepare the k and t maps of maheshwaram watershed in hard rock terrain in india

sulfur geochemistry of hydrothermal waters in yellowstone national park i the origin of thiosulfate in hot spring waters thiosulfate s sub 2 o sub 3 sup 2 minus polythionate s sub x o sub 6 sup 2 minus dissolved sulfide h sub 2 s and sulfate so sub 4 sup 2 minus concentrations in thirty nine alkaline and acidic springs in yellowstone national park ynp were determined the analyses were conducted on site using ion chromatography for thiosulfate polythionate and sulfate and using colorimetry for dissolved sulfide thiosulfate was detected at concentrations typically less than 2 micro mol l in neutral and alkaline chloride springs with low sulfate concentrations cl sup minus so sub 4 sup 2 minus 25 the thiosulfate concentration levels are about one to two orders of magnitude lower than the concentration of dissolved sulfide in these springs in most acid sulfate and acid sulfate chloride springs cl sup minus so sub 4 sup 2 minus 10 thiosulfate concentrations were also typically lower than 2 micro mol l however in some chloride springs enriched with sulfate cl sup minus so sub 4 sup 2 minus between 10 and 25 thiosulfate was found at concentrations ranging from 9 to 95 micro mol l higher than the concentrations of dissolved sulfide in these waters polythionate was detected only in cinder pool norris geyser basin at concentrations up to 8 micro mol l with an average s chain length from 4 1 to 4 9 sulfur atoms the results indicate that no thiosulfate occurs in the deeper parts of themore hydrothermal system thiosulfate may form however from 1 hydrolysis of native sulfur by hydrothermal solutions in the shallower parts 50 m of the system 2 oxidation of dissolved sulfide upon mixing of a deep hydrothermal water with aerated shallow groundwater and 3 the oxidation of dissolved sulfide by dissolved oxygen upon discharge of the hot spring upon discharge of a sulfide containing hydrothermal water oxidation proceeds rapidly as atmospheric oxygen enters the water the transfer of oxygen is particularly effective if the hydrothermal discharge is turbulent and has a large surface area less

influx and efflux of moisture in a desert soil during a 1 year period spatial and temporal variation of moisture flux in soil over a 1 year period was studied in the thar desert of india tritium was injected at a depth of 0 8 m at 18 sites distributed over an area of 50 km2 and at 20 adjacent points at a single site over a sand dune before the 1994 monsoon vertical soil profiles were collected from the 18 sites after the end of monsoon and at the end of the year and from the multiple injections site at different time intervals throughout the year moisture flux values computed from tritium and moisture distribution in soil profiles show that the moisture influx at a site depends upon the grain size of the top 20 cm layer and that about 68 of the total influx of water below the injection depth is lost during the summer months the data for the multiple injections site show that the tritium spike was displaced to a depth of 4 m by the end of the monsoon and it remained stationary during the postmonsoon period of 8 months although about 64 of the soil moisture was lost the spiked layer showed enrichment in the specific activity of tritium during summer months these observations suggest that vapor diffusion is the dominant process for moisture loss from the thar desert soil the net input natural recharge to groundwater due to 1994 precipitation was 62 mm

combined estimation of specific yield and natural recharge in a semi arid groundwater basin with irrigated agriculture a water budget approach is developed to jointly estimate specific yield and natural recharge in an unconfined aquifer with significant seasonal water table fluctuations water table fluctuations are due to distinct seasonality in groundwater recharge the separation of the hydrologic year into two or more extended seasons of recharge wet season and no recharge dry season with accompanying changes in water table allows for a split use of the water table fluctuation wtf method first to estimate specific yield from the water table drop during the dry season no recharge and second to estimate recharge from the water table rise during the wet season after considering all other water budget components explicitly the latter includes explicit computation of groundwater storage with the wtf method the application of the wtf method requires a large number of water level measurements throughout the unconfined aquifer before and after each season the advantage of the method is that specific yield and recharge are estimated at the scale of interest to basin hydrologic studies and that the method requires no extensive in situ instrumentation network here the method is demonstrated through a case study in a fractured hard rock aquifer subject to intensive groundwater pumping for irrigation purposes

elevated carbon dioxide flux at the dixie valley geothermal field nevada relations between surface phenomena and the geothermal reservoir abstract in the later part of the 1990s a large die off of desert shrubs occurred over an approximately 1 km 2 area in the northwestern section of the dixie valley dv geothermal field this paper reports results from accumulation chamber measurements of soil co 2 flux from locations in the dead zone and stable isotope and chemical data on fluids from fumaroles shallow wells and geothermal production wells within and adjacent to the dead zone a cumulative probability plot shows three types of flux sites within the dead zone locations with a normal background co 2 flux 7 g m 2 day 1 moderate flux sites displaying excess geothermal flux and high flux sites near young vents and fumaroles a maximum co 2 flux of 570 g m 2 day 1 was measured at a location adjacent to a fumarole using statistical methods appropriate for lognormally distributed populations of data estimates of the geothermal flux range from 7 5 t day 1 from a 0 14 km 2 site near the stillwater fault to 0 1 t day 1 from a 0 01 km 2 location of steaming ground on the valley floor anomalous co 2 flux is positively correlated with shallow temperature anomalies the anomalous flux associated with the entire dead zone area declined about 35 over a 6 month period the decline was most notable at a hot zone located on an alluvial fan and in the sg located on the valley floor gas geochemistry indicates that older established fumaroles along the stillwater fault and a 2 year old vent in the lower section of the dead zone discharge a mixture of geothermal gases and air or gases from air saturated meteoric water asmw stable isotope data indicate that steam from the smaller fumaroles is produced by 100 c boiling of these mixed fluids and reservoir fluid steam from the senator fumarole sf and from shallow wells penetrating the dead zone are probably derived by 140 c to 160 c boiling of reservoir fluid carbon 13 isotope data suggest that the reservoir co 2 is produced mainly by thermal decarbonation of hydrothermal calcite in veins that cut reservoir rocks formation of the dead zone is linked to the reservoir pressure decline caused by continuous reservoir drawdown from 1986 to present these reservoir changes have restricted flow and induced boiling in a subsurface hydrothermal outflow plume extending from the stillwater fault southeast toward the dv floor we estimate that maximum co 2 flux in the upflow zone along the stillwater fault in 1998 was roughly seven to eight times greater than the pre production flux in 1986 the eventual decline in co 2 flux reflects the drying out of the outflow plume

sources fate and flux of riverine solutes in the southwest yellowstone plateau volcanic field usa abstract since the 1970s temporal variations of hydrothermal discharge and thermal output from the numerous hydrothermal features in the yellowstone plateau volcanic field ypvf have been studied by measuring the chloride flux in the major rivers in this study the sources fate and flux of solutes in the fall river and its major tributaries in southwest yellowstone national park were determined the considerable precipitation in southwest ypvf and high groundwater flow through quaternary rhyolites results in river solute fluxes that originate from shallow non thermal groundwater and deep thermal water specific conductance serves as a surrogate measure for thirteen riverine solute concentrations combining continuous 15 minute specific conductance and discharge data the annual chloride arsenic fluoride and silica fluxes from the fall river were determined to be 11 5 25 and 19 of the total flux exiting ypvf approximately 11 of the fall river chloride flux is from non thermal waters which is larger than the previous estimate of 4 to 6 furthermore a large proportion of fluoride and silica in the fall river are derived from water rock interaction in the shallow non thermal groundwater system and the non thermal weathering rate 30 2 t yr km2 is higher than other rivers draining the yellowstone caldera consequently 73 3 of the annual total dissolved solid flux in the fall river is from thermal sources synoptic sampling of river water and discharge measurements was performed during low flow conditions that allowed for the determination of solute sources and their downstream fate it was determined that chloride sodium arsenic rubidium lithium and boron are primarily 89 associated with thermal waters and the bechler river is the primary source of most hydrothermal solutes in the fall river but the major source of arsenic is boundary creek using the chloride inventory method the thermal water discharge from several thermal areas was also determined

a geochemical model of the platanares geothermal system honduras abstract results of exploration drilling combined with results of geologic geophysical and hydrogeochemical investigations have been used to construct a geochemical model of the platanares geothermal system honduras three coreholes were drilled two of which produced fluids from fractured miocene andesite and altered cretaceous to eocene conglomerate at 450 to 680 m depth large volume artesian flows of 160 165 c predominantly bicarbonate water are chemically similar to but slightly less saline than widespread boiling hot spring waters the chemistry of the produced fluid is dominated by equilibrium reactions in sedimentary rocks at greater depths and higher temperatures than those measured in the wells chemical isotope and gas geothermometers indicate a deep fluid temperature of 200 245 c and reflect a relatively short residence time in the fractures feeding the wells chloride enthalpy relations as well as isotopic and chemical compositions of well discharges thermal springs and local cold waters support a conceptual model of ascending high temperature minimum 225 c parent fluid that has cooled conductively to form the 160 165 c shallow to 680 m fluid encountered by the wells the hot spring waters are formed by boiling and steam loss from more or less conductively cooled parent fluid the more dilute boiling spring waters cl 32 mg kg have cooled from 225 c to about 160 c by conduction and from 160 c to 98 c by boiling the most concentrated boiling spring waters cl 37 mg kg have cooled from 225 c to about 200 c by conduction and from 200 c to 98 c by boiling intermediate concentrations reflect mixed cooling paths

valles caldera region new mexico and the emerging continental scientific drilling program valles caldera is best known in recent years as an excellent example of a resurgent caldera smith and bailey 1968 and as the site of a high temperature geothermal system dondanville 1978 however valles caldera and the surrounding jemez mountains volcanic field possess a rich history of geologic research that dates back to the late 1800s through the years the research focus has changed as different economic and scientific factors have exerted their influence early work emphasized mining activity while modern work has stressed volcanology and later geothermal development only in the last 5 years has it been possible to view the region as a dynamic integrated magma hydrothermal system having a complex evolution lasting more than 13 m y gardner et al 1986 goff and nielson 1986 self et al 1986

rock cut stability assessment in mountainous regions ensuring stability of rock slopes is an essential requirement in the progress of our societies today rock determined to be loose or with potential for failure must be removed or restrained in some way in our work after doing an inventory of the instabilities that occurred in the last 5 years in the basque country we analyse the different factors in slope stability the potential for failure is evaluated for different classes of rock mass characterized previously by their geomechanical properties the characterization of potential risk of each one is undertaken by considering 10 parameters that define the nature of mass rock relative orientation and morphological features of the slope interaction rock massif slope and infrastructure features interaction rock massif slope infrastructure each of these parameters is evaluated separately and a risk factor rf is determined the rf reaches a maximum value of 10 000 and allows to differentiate four categories of slopes each category has its own priority rock mass characteristics also determine the potential damage from instability and the associated correction measures the systematic evaluation of instabilities must allow establishing a priority in the correction measures and thus optimise the available economic resources

isotopic and chemical composition of water and steam discharges from volcanic magmatic hydrothermal systems of the guanacaste geothermal province costa rica the guanacaste geothermal province encompasses three major geothermal systems each centered on its respective volcanic structure rincon de la vieja to the nw miravalles in the center and tenorioto the se each shows corresponding sets of surface manifestations vapor discharges from fumaroles and steam heated pools at altitudes 500 m lower temperature so4cl springs on the lower slopes of the respective volcano and cooler neutral cl springs to the s of the volcanic chain at altitudes 500 m the production of hco3 rich waters is limited to a narrow belt stretching to the s of miravalles volcano chemical and isotopic evidence suggests that the neutral cl waters also discharged from deep wells are derived from a more primitive clso4 water formed by transfer of readily mobilised originally magmatic constituents to deeply circulating groundwater isotopic evidence suggests that this groundwater is derived largely from areas to the north of the volcanic chain the presence of immature waters within drillable depth is indicated by the incursion of an acid so4 water into a well at miravalles after deepening to 2000 m as the cl waters rise they start to boil the separated vapors feed the fumaroles and steam heated features at the surface the residual water travels underground to be discharged some 5 25 km to the s the uniformity in chemical and isotopic compositions of the neutral cl waters is compatible with the assumption that the individual thermal systems are linked at depth to form large contiguous geothermal reservoirs beneath the guanacaste geothermal province

helium isotope and gas discharge variations associated with crustal unrest in long valley caldera california 1989 1992 the onset of anomalous seismic activity in 1989 beneath mammoth mountain on the southwestern rim of the long valley caldera california was followed within approximately 4 months by a large increase in sup 3 he sup 4 he in vapor discharged from a fumarole on the north side of the mountain the helium isotopic ratio at this vent rose to a maximum of 6 7 r sub a in july 1990 and subsequently declined to values near 5 r sub a potential sources of the sup 3 he rich vapors include degassing of fresh magma degassing from fresh surfaces generated in newly fractured igneous rocks and volatile release from a sup 3 he rich gas chamber situated above previously emplaced intrusives the magnitude of the increase in helium isotopic composition from 3 8 to 6 7 r sub a the persistence of relatively high values 5 r sub a over a period of 3 years the increase in the flux of total he relative to gases in air saturated water and the increases in the rates of discharge of steam and gas from this fumarole indicate that magmatic intrusion did in fact begin in 1989 beneath mammoth mountain seismic activity and limited measurements of extensional deformation at the surface suggest that the depth of intrusion maymore be as shallow as 2 km consistent with the prompt appearance of increased sup 3 he sup 4 he ratios in the fumarolic gas and that the intrusive process may have persisted for approximately 1 year in contrast a similar combination of magmatic intrusion and anomalous seismic activity beneath the resurgent dome south moat region during the 1989 1991 period resulted in at most relatively small changes in sup 3 he sup 4 he in fumarolic discharge at the southern edge of the resurgent dome the more subdued response may result from a combination of greater intrusive depths and greater dilution of sup 3 he rich inputs to thermal fluid reservoirs in the shallow hydrothermal system in this area compared with mammoth mountain 60 refs 11 figs 4 tabs less

lithologically constrained rainfall lcr method for estimating spatio temporal recharge distribution in crystalline rocks summary a lithologically constrained rainfall lcr method has been developed to estimate the spatial and temporal natural recharge distribution a complex and high variable hydrological parameter in hard rocks the lithological constraints are coupled to the rainfall in terms of soil resistivity s and vadose zone thickness h in the absence of a bore well in an over exploited area with deep water table it is difficult to get the water table precisely from any surface exploration methods such as remote sensing and geophysics however water table variation being close to the basement in this situation depth to basement was used as an alternative to the vadose zone thickness which yielded equally reliable estimate the method facilitates to estimate temporal due to time varying rainfall and spatial due to lithological variability distribution of natural recharge for many numbers of years say 50 by inputting the precipitation of corresponding years provided once hydrogeophysical s and h parameters are known the method has been successfully validated and applied to study the watershed scale in a granitic terrain and found that the variability is much higher than otherwise expected or estimated by a single method

3he evidence for a wide zone of active mantle melting beneath the central andes we report results of a regional survey of helium isotopes measured in water and gas samples in volcanic sulfataras and geothermal springs from the central andes of northern chile and bolivia between the latitudes 15 s and 23 s the highest 3he4he ratios reported as rra ratios r sample 3he4he ra air 3he4he are associated with the active volcanic arc of the western cordillera 0 92 rra 5 52 and approach ratios found at other convergent margins in the circum pacific region a significant 3he component is also present in fluid and gas samples from the high altiplano plateau 0 48 rra 3 56 and the eastern cordillera 0 03 rra 1 2 up to 300 km east of the active arc and more than 300 km above the subducting slab this wide zone of 3he anomalies is delineated both to the east and the west by regions with low 3he4he ratios 0 2ra typical of radiogenic helium production in the crust studies of the regional groundwater regime suggest that the wide zone of elevated 3he4he values away from the active volcanic arc is unlikely to be caused by lateral and shallow transport of magmatic helium and there is no evidence for significant crustal sources of 3he the high 3he4he ratios are interpreted as reflecting degassing of volatiles from mantle derived magmas emplaced over an area 400 km wide beneath and into crust up to 75 km thick the subducting slab is at depths of 100 350 km in this region in the west underneath the active volcanic arc mantle melting is probably largely controlled by mantle hydration and dehydration and the helium isotope data can be used to delineate the extent of the asthenospheric mantle wedge at depth in contrast mantle melting behind the arc beneath the altiplano and eastern cordillera may be a result of convective removal of the base of the lithosphere the sharp cut off in the mantle helium signal in the east is interpreted as marking the western edge of thick and relatively cold lithosphere devoid of mantle melts which could transport mantle volatiles towards the surface this may coincide with the limit of underthrusting of the brazilian shield beneath the eastern margin of the central andes

hydrothermal petroleums from yellowstone national park wyoming u s a abstract in yellowstone national park oil is actively discharging with thermal waters at several widely separated thermal areas samples from two locations were studied petroleum from calcite springs occurs as vapor condensates in steam vents detailed geochemical analyses show a complex origin for the petroleum fluid deeply buried hydrothermally altered sedimentary rocks are believed to have contributed a high temperature pyrolysate consisting largely of polynuclear aromatic hydrocarbons and heterocyclic compounds shallow sedimentary rocks which are also hydrothermally altered have contributed large amounts of aromatic and polar compounds as well as minor amounts of hydrocarbons the permian phosphoria formation is suggested as a likely source rock for the bulk of the oils autochthonous pyrolysates and lipids from thermally altered surface and near surface bacterial and land plant debris have also been introduced to the vents the latter may have been introduced by downward percolating meteoric water the oil from rainbow springs is a highly paraffinic low s crude oil depleted in light hydrocarbons unlike the calcite springs samples the oil from rainbow springs is believed to have originated from a single sedimentary source rock with little or no hydrocarbon contributions from surface biota the oil contains a unique molecular marker assemblage that suggests both gymnosperm and angiosperm input and places the age of the source unit in the tertiary consideration of the local stratigraphy and water temperatures limits the probable source zone to the eocene aycross formation an intra volcanic lacustrine mudstone calculation of deep water temperatures indicates that this unit is exposed to thermal waters in an extensive near surface aquifer such conditions are consistent with the widespread surface manifestations and biomarker kinetic models consideration of the petroleum chemistry and regional hydrodynamics indicates that the yellowstone park oils did not migrate into the park from distant sources the chemical data are also inconsistent with the oils being generated and trapped prior to tertiary volcanism at both calcite springs and rainbow springs oil generation appears to be contemporaneous and is attributed to thermal alteration of relatively shallow sedimentary rocks by hydrothermal fluids

remotely triggered seismicity in the yellowstone national park region by the 2002 mw 7 9 denali fault earthquake alaska coincident with the arrival of low frequency large amplitude surface waves of the mw 7 9 denali fault earthquake dfe an abrupt increase in seismicity was observed in the yellowstone national park region despite the large epicentral distance of 3100 km within the first 24 hr following the dfe mainshock we located more than 250 earthquakes which occurred throughout the entire yellowstone na tional park region the elevated seismicity rate continued for about 30 days and followed a modified omori law decay with a p value of 1 02 0 07 for a declus tered earthquake catalog the seismicity following the 2002 dfe uniquely stands out with a significance of 30r the increase in seismicity occurred over all magnitude bands in general we observed that seismicity following the dfe outlined the spatial pattern of past seismicity routinely observed in the yellowstone national parkregion however we found significant differences in triggered seismicity inside and outside the caldera earthquakes inside the yellowstone caldera occurred preferentially as clusters close to major hydrothermal systems were of larger magnitude and seis micity decayed more rapidly this suggests that either different trigger mechanisms were operating inside and outside the caldera or that the crust responded differently to the same trigger mechanism depending on its different mechanicalstate compared with other sites that experienced remote earthquake triggering following the 2002 dfe yellowstone showed the most vigorous earthquake activity we attribute this to strong directivity effects of the dfe which caused relatively large peak dynamic stresses 0 16 0 22 mpa in yellowstone and to the volcanic nature of yellowstone

spatial and temporal geochemical trends in the hydrothermal system of yellowstone national park inferences from river solute fluxes we present and analyze a chemical dataset that includes the concentrations and fluxes of hco3 s o4 c l and f in the major rivers draining yellowstone national park ynp for the 2002 2004 water years 1 october 2001 30 september 2004 the total molar flux in all rivers decreases in the following order hco3 ncl nso4 nf but each river is characterized by a distinct chemical composition implying large scale spatial heterogeneity in the inputs of the various solutes the data also display nonuniform temporal trends whereas solute concentrations and fluxes are nearly constant during base flow conditions concentrations decrease solute fluxes increase and hco3 cl and so4 cl increase during the late spring high flow period hco3 so4 decreases with increasing discharge in the madison and falls rivers but increases with discharge in the yellowstone and snake rivers the non linear relations between solute concentrations and river discharge and the change in anion ratios associated with spring runoff are explained by mixing between two components 1 a component that is discharged during base flow conditions and 2 a component associated with snow melt runoff characterized by higher hco3 cl and so4 cl the fraction of the second component is greater in the yellowstone and snake rivers which host lakes in their drainage basins and where a large fraction of the solute flux follows thaw of ice cover in the spring months although the total river hco3 flux is larger than the flux of other solutes hco3 cl 3 the co2 equivalent flux is only 1 of the estimated emission of magmatic co2 soil emissions from yellowstone no anomalous solute flux in response to perturbations in the hydrothermal system was observed possibly because gage locations are too distant from areas of disturbance or because of the relatively low sampling frequency in order to detect changes in river hydrothermal solute fluxes sampling at higher frequencies with better spatial coverage would be required our analysis also suggests that it might be more feasible to detect large scale heating or cooling of the hydrothermal system by tracking changes in gas and steam flux than by tracking changes in river solute flux published by elsevier b v

emplacement of the longmen shan thrust nappe belt along the eastern margin of the tibetan plateau abstract the topographic descent from the eastern margin of the tibetan plateau to the sichuan basin passes through the longmen shan thrust nappe belt which is sub divided by six nw dipping major listric thrusts with accompanying duplexes and imbricate fans into five large scale nappes each nappe has its own stratigraphic and deformational features in the inner longmen shan longmen mountains allochthonous nappe units have incorporated both mesoproterozoic basement and sinian neoproterozoic to triassic cover sequences as thick skinned horses whereas in the frontal longmen shan sinian cretaceous cover sediments have been stripped from the basement as thin skinned fold and thrust sheets including the extensively distributed klippen structures pre thrusting extension during devonian to middle late triassic times resulted in syn depositional normal faults structural inversion of these faults initiated the peng xian guan xian basement complex jiuding shan and tangwangzhai nappes during the early episode of the indosinian orogeny norian to rhaetian this was followed by episodic thrusting during latest triassic to early cretaceous times to develop the guan xian an xian and southeastern marginal nappes that have incorporated sediments from the neighbouring foreland basin into the frontal part of the thrust nappe belt during a late miocene reactivation of the pre existing thrusts differential thrusting occurred across the thrust nappe belt

crust and upper mantle p wave velocity structure beneath valles caldera new mexico results from the jemez teleseismic tomography experiment new results are presented from the teleseismic component of the jemez tomography experiment conducted across valles caldera in northern new mexico we invert 4872 relative ital p wave arrival times recorded on 50 portable stations to determine velocity structure to depths of 40 km the three principle features of our model for valles caldera are 1 near surface low velocities of minus 17 percent beneath the toledo embayment and the valle grande 2 midcrustal low velocities of minus 23 percent in an ellipsoidal volume underneath the northwest quadrant of the caldera and 3 a broad zone of low velocities minus 15 percent in the lower crust or upper mantle crust shallower than 20 km is generally fast to the northwest of the caldera and slow to the southeast near surface low velocities are interpreted as thick deposits of bandelier tuff and postcaldera volcaniclastic rocks lateral variation in the thickness of these deposits supports increased caldera collapse to the southeast beneath the valle grande we interpret the midcrustal low velocity zone to contain a minimum melt fraction of 10 percent while we cannot rule out the possibility that this zone is the remnant 1 2 ma bandelier magma chamber the eruption history and geochemistry of the volcanic rocks erupted in valles calderamore following the bandelier tuff make it more likely that magma results from a new pulse of intrusion indicating that melt flux into the upper crust beneath valles caldera continues the low velocity zone near the crust mantle boundary is consistent with either partial melt in the lower crust or mafic rocks without partial melt in the upper mantle in either case this low velocity anomaly indicates that underplating by mantle derived melts has occurred copyright 1998 american geophysical union less

a dynamic comprehensive method for landslide control a slope failure is developed due to progressive external loads and deteriorations of slope geomaterials thus forming a progressive and dynamic development and occurrence of landslides site geological properties and other active factors such as hydrodynamic load and human activities are complex and usually unknown thus this dynamic development and occurrence of landslides can only be understood through the progressive accumulation of knowledge on the landslides for such a progressive process this paper proposes a dynamic comprehensive control method for landslide control this control method takes full advantage of updated monitoring data and site investigations of landslides and emphasizes the implementation of possible measures for landslide control at reasonable stages and in different groups these measures are to prevent the occurrence of a landslide disaster as a case study a landslide project at the panluo open pit iron mine is analyzed to illustrate this dynamic comprehensive control method

hot dry rock geothermal reservoir testing 1978 to 1980 abstract the phase i hot dry rock geothermal energy reservoirs at the fenton hill field site grew continuously during run segments 2 through 5 january 1978 to december 1980 reservoir growth was caused not only by pressurization and hydraulic fracturing but also by heat extraction and thermal contraction effects reservoir heat transfer area grew from 8000 to 50 000 m2 and reservoir fracture volume grew from 11 to 266 m3 despite this reservoir growth the water loss rate increased only 30 under similar pressure environments for comparable temperature and pressure conditions the flow impedance a measure of the resistance to circulation of water through the reservoir remained essentially unchanged and if reproduced in the phase ii reservoir under development could result in self pumping geochemical and seismic hazards have been nonexistent in the phase i reservoirs the produced water is relatively low in total dissolved solids and shows little tendency for corrosion or scaling the largest microearthquake associated with heat extraction measures less than minus one on the extrapolated richter scale

a time space based approach for mapping rainfall induced shallow landslide hazard a rainfall induced shallow landslide is a major hazard in mountainous terrain but a time space based approach is still an unsettled issue for mapping rainfall induced shallow landslide hazards rain induces a rise of the groundwater level and an increase in pore water pressure that results in slope failures in this study an integrated infinite slope analysis model has been developed to evaluate the influence of infiltration on surficial stability of slopes by the limit equilibrium method based on this new integrated infinite slope analysis model a time space based approach has been implemented to map the distributed landslide hazard in a gis geographic information systems and to evaluate the shallow slope failure induced by a particular rainfall event that accounts for the rainfall intensity and duration the case study results in a comprehensive time space landslide hazard map that illustrates the change of the safety factor and the depth of the wetting front over time

geothermal gas compositions in yellowstone national park usa abstract gas samples collected between 1974 and 1986 have been analysed for the ten major components samples have been collected almost exclusively from the tops of pools which has degraded the value of the data and limited inter comparisons to the relatively insoluble components ar n 2 ch 4 h 2 and he a general gas distribution pattern in the park in terms of these components shows the major heat source s to underlie the gibbon and mud volcano areas with all other geothermal areas having gas compositions consistent with a general north south water flow shoshone basin gases show a large range of compositions and these are analysed in detail the patterns conform to that which would be expected from an east west flow or fluid with progressive boiling and subsequent dilution

detection of seepage paths in earth dams using self potential and electrical resistivity methods abstract earth and rockfill dams are designed to operate under steady state seepage anomalous seepage may be a threat to the integrity of the structure in spite of advances made in the fields of geotechnical engineering it is not possible to have 100 leak proof structure any excessive and unplanned seepage may lead to the failure of the dam especially in unconsolidated or fractured terrains geophysical methods play an important role in mapping seepage paths and monitoring the changes of the seepage with time enabling to plan technically and economically worthwhile remedial measures in the present paper utilisation of electrical methods for delineation of seepage zones at two of the four saddle dams of the som kamla amba project rajasthan state india which is founded on heterogeneous rock mass is discussed electrical resistivity method was used to delineate zones favourable for seepage whereas self potential sp method was used to delineate the seepage paths sp measurements have shown negative anomaly of the order of 10 20 mv in amplitude indicating low seepage coinciding with the seepage measurements made by the project authorities

hydrothermal changes related to earthquake activity at mud volcano yellowstone national park wyoming the mud volcano hydrothermal area in yellowstone national park is near the intersection of a 20 km long zone of northeast trending normal faults with the eastern resurgent dome within the 600 000 year old yellowstone caldera recent crustal uplift along the northeast trending axis of the caldera is at a maximum 700 mm since 1923 near the mud volcano area from 1973 through april 1978 less than 10 earthquakes largest m 2 4 were located within 3 km of the mud volcano area in may 1978 earthquakes began occurring beneath the hydrothermal area at depths of 1 to 5 km the seismic activity continued until the end of november with intense swarms 100 events per hour occurring on october 23 and november 7 the largest event m 3 1 occurred on november 14 and at least 8 events were m 2 5 or larger in december 1978 heat flux in the mud volcano hydrothermal features began increasing along a 2 km long northeast trending zone existing mud cauldrons became more active new mud cauldrons and fumeroles were formed and vegetation primarily lodgepole pine was killed by increased soil temperature the increase in heat flux continued through july 1979 then gradually declined reaching the early 1978 level by june 1980 the spatial and temporal association of earthquakes and increased hydrothermal activity at mud volcano suggests that the seismic activity expanded preexisting fracture systems premitting increased fluid flow from depths of several kilometers

estimating net aquifer recharge and zonal hydraulic conductivity values for mahi right bank canal project area india by genetic algorithm abstract the paper presents a recent approach for inverse modeling of groundwater systems based upon a generic algorithm ga global optimization technique which is coupled with a galerkin s finite element fem flow simulation model applicability adequacy and robustness of the developed numerical model is tested by estimating the transmissivity parameter in various zones of a synthetic confined aquifer the numerical model is applied to estimate hydraulic conductivity and recharge parameters of various zones in the mahi right bank canal mrbc project area the solutions of synthetic and field aquifer problems are compared with another inverse model using the gauss newton marquardt gnm method largely the ga results are better compared to gnm parameter estimates except when no measurement errors in the observation head values are assumed head distribution computed using the estimated parameters for the mrbc aquifer is found closer to observed head distribution in the aquifer domain from the adequacy of the estimated parameters the study concludes that the genetic algorithm approach can be successfully used for inverse modeling of regional aquifers where reliable parameter estimation is an important but difficult task for real system simulation

the use of tritium in groundwater to determine fluid mean residence times of valles caldera hydrothermal fluids new mexico usa abstract naturally and artificially produced 3 h in precipitation is used to place limits on mean residence times of fluids associated with the valles caldera geothermal reservoir the 3 h concentrations in precipitation are used to calculate fluid mean residence times using two end member cases piston flow and well mixed reservoirs these simplified models using 3 h yield relative fluid mean residence times in different portions of the system in situ 3 h production in the reservoir through neutron interaction with 6 li is considered and only very low levels of 3 h 0 01 t u are contributed to the waters by this process calculations using the end member cases at valles caldera indicate that mean residence times of geothermal waters in the reservoir are between 3000 and 10 000 years the results also show that the two distinct subsystems of the main reservoir are associated with different fluid mean residence times waters in the redondo creek subsystem are older 4300 to 10 000 years than waters in the sulphur springs subsystem 2000 4400 years comparison of the results of the end member cases with those obtained using more sophisticated methods indicates that the two end member cases with the use of 3 h can provide acceptable limits order of magnitude on a fluid s mean residence time and volumes within a reservoir

fluid inclusion evidence for rapid formation of the vapor dominated zone at sulphur springs valles caldera new mexico usa abstract microthermometric measurements were obtained for 618 fluid inclusions in hydrothermal quartz fluorite and calcite and magmatic quartz phenocrysts in intracaldera tuffs from the vc 2a core hole in order to study evolutionary processes of the sulphur springs hydrothermal system in the valles caldera relatively high t h values in samples from shallow depths indicate erosion of about 200 m of caldera fill since deposition of hydrothermal minerals at shallow depths in the sulphur springs hydrothermal system accompanied by a descent in the water table of the liquid dominated reservoir for samples collected below the current water level of the well the minimum values of homogenization temperature t h fit the present thermal profile whereas minimum t h values of samples from above the water level are several tens of degrees higher than the present thermal profile and fit a paleo thermal profile following the boiling point curve for pure water as adjusted to 92 c at 20 m below the present land surface this is attributed to development of an evolving vapor zone that formed subsequent to a sudden drop in the water table of the liquid dominated reservoir we suggest that these events were caused by the drainage of an intracaldera lake when the southwestern wall of the caldera was breached about 0 5 ma this model indicates that vapor zones above major liquid dominated geothermal reservoirs can be formed due to dramatic changes in geohydrology and not just from simple boiling