fault controlled soil co2 degassing and shallow magma bodies summit and lower east rift of kilauea volcano hawaii 1997 soil co2 flux measurements were carried out along traverses across mapped faults and eruptive fissures on the summit and the lower east rift zone of kilauea volcano anomalous levels of soil degassing were found for 44 of the tectonic structures and 47 of the eruptive fissures intercepted by the surveyed profiles this result contrasts with what was recently observed on mt etna where most of the surveyed faults were associated with anomalous soil degassing the difference is probably related to the differences in the state of activity at the time when soil gas measurements were made kilauea was erupting whereas mt etna was quiescent although in a pre eruptive stage unlike mt etna flank degassing on kilauea is restricted to the tectonic and volcanic structures directly connected to the magma reservoir feeding the ongoing east rift eruption or in areas of the lower east rift where other shallow likely independent reservoirs are postulated anomalous soil degassing was also found in areas without surface evidence of faults thus suggesting the possibility of previously unknown structures

revised calendar date for the taupo eruption derived by 14c wiggle matching using a new zealand kauri 14c calibration data set taupo volcano in central north island new zealand is the most frequently active and productive rhyolite volcano on earth its latest explosive activity about 1800 years ago generated the spectacu

soil co2 degassing along tectonic structures of mount etna sicily the pernicana fault abstract carbon dioxide emissions from the soil have been investigated along lines of equally spaced sampling points perpendicular to the pernicana fault on mt etna anomalous values of soil co2 have been found not only along the fault plane but also along directions parallel to it both to the n and to the s of the main fault the acquired data seem to reveal a shallow step like geometry of the pernicana fault system with parallel faults being generally not deeper than the interface between etna s volcanic cover and its sedimentary basement a few hundred meters the distribution of the anomalous co2 emissions has also revealed that the pernicana fault continues at least as far as the ionian sea in an area where only sedimentary rocks crop out this finding would suggest that the main structure is deeper than the base of the volcanic cover thus cutting at least the uppermost portion of etna s sedimentary basement isotopic analyses of c carried out in samples from locations of high co2 seem to indicate that the emitted co2 is a mixture of an organic shallow component and a minor deeper magmatic one both chemical and isotopic data on soil gases emitted in the easternmost part of the studied area distinguished another tectonic structure which seems to be much deeper than the pernicana fault and is roughly directed nne ssw this direction being coincident with an important structural trend of eastern sicily

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

ages of 24 widespread tephras erupted since 30 000 years ago in new zealand with re evaluation of the timing and palaeoclimatic implications of the lateglacial cool episode recorded at kaipo bog abstract tephras are important for the nz intimate project because they link all three records comprising the composite inter regional stratotype developed for the new zealand climate event stratigraphy nz ces here we firstly report new calendar ages for 24 widespread marker tephras erupted since 30 000 calendar cal years ago in new zealand to help facilitate their use as chronostratigraphic dating tools for the nz ces and for other palaeoenvironmental and geological applications the selected tephras comprise 12 rhyolitic tephras from taupo nine rhyolitic tephras from okataina one peralkaline rhyolitic tephra from tuhua and one andesitic tephra each from tongariro and egmont taranaki volcanic centres age models for the tephras were obtained using three methods i 14 c based wiggle match dating of wood from trees killed by volcanic eruptions these dates published previously ii flexible depositional modelling of a high resolution 14 c dated age depth sequence at kaipo bog using two bayesian based modelling programs bacon and oxcal s p sequence function and the intcal09 data set with sh offset correction 44 17 yr and iii calibration of 14 c ages using oxcal s tau boundary function and the shcal04 and intcal09 data sets our preferred dates or calibrated ages for the 24 tephras are as follows youngest to oldest all mid point or mean ages of 95 probability ranges kaharoa ad 1314 12 taupo unit y ad 232 10 mapara unit x 2059 118 cal yr bp whakaipo unit v 2800 60 cal yr bp waimihia unit s 3401 108 cal yr bp stent unit q 4322 112 cal yr bp unit k 5111 210 cal yr bp whakatane 5526 145 cal yr bp tuhua 6577 547 cal yr bp mamaku 7940 257 cal yr bp rotoma 9423 120 cal yr bp opepe unit e 9991 160 cal yr bp poronui unit c 11 170 115 cal yr bp karapiti unit b 11 460 172 cal yr bp okupata 11 767 192 cal yr bp konini bed b 11 880 183 cal yr bp waiohau 14 009 155 cal yr bp rotorua 15 635 412 cal yr bp rerewhakaaitu 17 496 462 cal yr bp okareka 21 858 290 cal yr bp te rere 25 171 964 cal yr bp kawakawa oruanui 25 358 162 cal yr bp poihipi 28 446 670 cal yr bp and okaia 28 621 1428 cal yr bp secondly we have re dated the start and end of the lateglacial cool episode climate event nzce 3 in the nz ces previously referred to as the lateglacial climate reversal as defined at kaipo bog in eastern north island new zealand using both bacon and oxcal p sequence modelling with the intcal09 data set the ca 1200 yr long cool episode indicated by a lithostratigraphic change in the kaipo peat sequence to grey mud with lowered carbon content and a high resolution pollen derived cooling signal began 13 739 125 cal yr bp and ended 12 550 140 cal yr bp mid point ages of the 95 highest posterior density regions bacon modelling the oxcal modelling generating almost identical ages confirmed these ages the lateglacial cool episode ca 13 8 12 6 cal ka bp thus overlaps a large part of the entire antarctic cold reversal chronozone ca 14 1 12 4 cal ka bp or ca 14 6 12 8 cal ka bp and an early part of the greenland stadial 1 younger dryas chronozone ca 12 9 11 7 cal ka bp the timing of the lateglacial cool episode at kaipo is broadly consistent with the latitudinal patterns in the antarctic cold reversal signal suggested for the new zealand archipelago from marine and terrestrial records and with records from southern south america

block tectonics of the island of hawaii from a focal mechanism analysis of basal slip the southern third of the island of hawaii is composed of at least three rigid blocks kilauea volcano s south flank mauna loa volcano s southeast flank and mauna loa volcano s west flank analysis of earthquake focal mechanisms suggests that kilauea s south flank the most mobile of these blocks is moving seaward perpendicular to its east rift zone along a southeasterly course at an azimuth of 155 5 mauna loa s southeastern flank is also moving in a southeasterly direction although at a slightly more easterly azimuth of 140 5 although data are sparse on the western flank of mauna loa due to low seismicity and inadequate seismic network station density the available data suggest that this region is translating seaward along a generally westerly azimuth relative differences in these translational azimuths may represent oblique opening across the boundaries between these regions the active rift zones of kilauea and mauna loa volcanoes

clay minerals oxyhydroxide formation element leaching and humus development in volcanic soils a weathering sequence with soils developing on volcanic trachy basaltic parent materials with ages ranging from 100 115 000 years in the etna region served as the basis to analyse and calculate the accumulation and stabilisation mechanisms of soil organic matter som the transformation of pedogenic fe and al the formation and transformation of clay minerals the weathering indices and by means of mass balance calculations net losses of the main elements although the soils were influenced by ash depositions during their development and the soil on the oldest lava flow developed to a great extent under a different climate leaching of elements and mineral formation and transformation could still be measured leaching of major base cations coupled with a corresponding passive enrichment of al or fe was a main weathering mechanism and was especially pronounced in the early stages of soil formation due to mineral or glass weathering with time the weathering indexes such as the k ca ti ratio tend to an asymptotic value chemical and mineralogical changes between 15 000 and 115 000 years in the a and b horizons were small in contrast to this the accumulation of newly formed itm imogolite type materials and ferrihydrite showed a rather linear behaviour with time weathering consisted of the dissolution of primary minerals such as plagioclase pyroxenes or olivine the breakdown of volcanic glass and the formation of secondary minerals such as itm and ferrihydrite the main mineral transformations were volcanic glass imogolite kaolinite clay fraction in the most weathered horizons a very small amount of 2 1 clay minerals could be found that were probably liberated from the inner part of volcanic glass debris the rate of formation and transformation of 2 1 clay minerals in the investigated soils was very low no major changes could be observed even after 115 000 years of soil evolution this can be explained by the addition of ash and the too low precipitation rates in general soil erosion played a subordinate role except possibly for the oldest soils 115 000 years the youngest soils with an age 2000 years had the highest accumulation rate of organic c about 3 0 g c m2 year after about 15 000 years the accumulation rate of organic c in the soils tended to zero soil organic carbon reached an asymptotic value with abundances close to 20 kg m2 after about 20 000 years in general the preservation and stabilisation of som were due to poorly crystalline al and fe phases pyrophosphate extractable kaolinite and the clay content these parameters correlated well with the organic c imogolite type material did not contribute significantly to the stabilisation of soil organic matter

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

soil gas geochemistry in relation to eruptive fissures on timanfaya volcano lanzarote island canary islands spain abstract we report herein the first results of an extensive soil gas survey performed on timanfaya volcano on may 2011 soil gas composition at timanfaya volcano indicates a main atmospheric source slightly enriched in co2 and he soil co2 concentration showed a very slight deep contribution of the timanfaya volcanic system with no clear relation to the main eruptive fissures of the studied area the existence of soil helium enrichments in timanfaya indicates a shallow degassing of crustal helium and other possible deeper sources probably form cooling magma bodies at depth the main soil helium enrichments were observed in good agreement with the main eruptive fissures of the 1730 36 eruption with the highest values located at those areas with a higher density of recent eruptive centers indicating an important structural control for the leakage of helium at timanfaya volcano atmospheric air slightly polluted by deep seated helium emissions co2 degassed from a cooling magma body and biogenic co2 might be the most plausible explanation for the existence of soil gas helium is a deep seated gas exhibiting important emission rates along the main eruptive fissure of the 1730 36 eruption of timanfaya volcano

summit outgassing as indicated by radon mercury and ph mapping kilauea volcano hawaii abstract surface geochemical mapping of rn hg and ph on the summit of kilauea volcano hawaii has shown some of the characteristics of outgassing rn concentrations measured in shallow ground gas are highest 10 to 155 units i e up to 0 016 nci l222rn over deep structures associated with the summit caldera low 1 to 5 units over the upper rift zones which are underlain by shallow intrusions and low to negative 1 to 3 units over most of the volcanically inactive peripheral areas high rn concentrations were measured over peripheral well developed structures such as the kaoiki and koae fault systems 45 and 12 units respectively the pattern of rn values broadly suggests the existence of a summit wide convection system interrupted locally by specific permeable structures the low ph 3 5 to 5 6 of soils over the caldera is suggested to be largely due to the sulfurous component of the ground gas the low concentrations of hg 5 to 80 ppb in these soils are postulated as being partly a function of subsurface complexing of hg with the abundant sulfur the shallow intrusions below the upper rift zones appear to have outgassed much of their sulfur content so soils in these areas are only slightly acid 5 6 to 6 2 allowing the accumulation of hg to concentrations of several thousands of ppb these conditions change during extrusive and intrusive events with the increases in shallow subsurface temperatures and volatiles in ground gas producing an increase in rn concentration and a decrease in soil hg due to volatilization after such events rn concentration decreases and soil hg increases significantly

dynamics of diffuse carbon dioxide emissions from cumbre vieja volcano la palma canary islands we report herein the results of 13 soil co2 efflux surveys at cumbre vieja volcano la palma island the most active basaltic volcano in the canary islands the co2 efflux measurements were undertaken using the accumulation chamber method between 2001 and 2013 to constrain the total co2 output from the studied area and to evaluate occasional co2 efflux surveys as a volcanic surveillance tool for cumbre vieja soil co2 efflux values ranged from non detectable up to 2442 g m 2 days 1 with the highest values observed in the south where the last volcanic eruption took place teneguia 1971 isotopic analyses of soil gas carbon dioxide suggest an organic origin as the main contribution to the co2 efflux with a very small magmatic gas component observed at the southern part of the volcano total biogenic and magmatic combined co2 emission rates showed a high temporal variability ranging between 320 and 1544 t days 1 and averaging 1147 t days 1 over the 220 km2 region two significant increases in the co2 emission observed in 2011 and 2013 were likely caused by an enhanced magmatic endogenous contribution revealed by significant changes in the 3he 4he ratio in a co2 rich cold spring the relatively stable emission rate presented in this work defines the background co2 emission range for cumbre vieja during a volcanic quiescence period

compositions and flux of soil gas in liu huang ku hydrothermal area northern taiwan abstract soil co 2 flux has been considered a useful proxy to remotely monitor volcanic activity in a hydrothermal area within a safe distance the liu huang ku lhk area which is close to the taipei basin and many existing active fumaroles and hot springs was chosen for the first systematic soil gas study in a hydrothermal area of taiwan in 2004 and 2006 the soil co 2 flux was measured by the closed chamber method with a non dispersive infrared detector soil co 2 emission rate was estimated 19 8 0 2 t day 1 and 582 t km 2 day 1 in 2004 and 22 4 0 2 t day 1 and 659 t km 2 day 1 in 2006 respectively these values are close to those reported for other active high co 2 flux hydrothermal areas of the world it implies that magmatic gases are actively degassing from subsurface in northern taiwan helium and carbon isotopic data reveal that soil gas in lhk is mainly derived from the mantle and is mixed with a small amount of crustal and air components the abundance of soil co 2 shows a positive correlation with the 3 he 4 he ratios and total sulfur contents which are considered as magmatic sensitive indicators for the fumarolic samples therefore soil co 2 could be used as a good proxy for future monitoring of magmatic activity in this area

aluminum speciation and equilibria in soil solutions of a haplorthod in the adirondack mountains new york u s a abstract aluminum chemistry was evaluated in throughfall and leachates from o e and b horizons of a spodosol typic haplorthod at hardwood and conifer sites in the adirondack mountains new york organic and fluoride complexes were the dominant forms of aluminum in all soil solutions and throughfall whereas sulfate and hydroxide complexes were less prevalent aquo aluminum concentrations were extremely low in o horizon leachates 6 and 7 of total inorganic aluminum at conifer and hardwood sites respectively and increased to 28 and 26 of total inorganic aluminum in solutions from b horizons at conifer and hardwood sites respectively acid soluble aluminum was 51 and 54 of total aluminum in o horizon leachates at the conifer and hardwood sites respectively and 88 of total aluminum in throughfall like aqueous aluminum soil bound aluminum was largely associated with organic matter solutions were generally undersaturated with respect to the solubility of aluminum sulfate and aluminum hydroxide mineral phases elevated concentrations of organic and non labile aluminum in forest floor solutions suggest that biocycling by vegetation may be an important mechanism of aluminum transport in forest ecosystems

weathering of the new albany shale kentucky usa i weathering zones defined by mineralogy and major element composition abstract comprehensive understanding of chemical and mineralogical changes induced by weathering is valuable information when considering the supply of nutrients and toxic elements from rocks here minerals that release and fix major elements during progressive weathering of a bed of devonian new albany shale in eastern kentucky are documented samples were collected from unweathered core parent shale and across an outcrop excavated into a hillside 40 year prior to sampling quantitative x ray diffraction mineralogical data record progressive shale alteration across the outcrop mineral compositional changes reflect subtle alteration processes such as incongruent dissolution and cation exchange altered primary minerals include k feldspars plagioclase calcite pyrite and chlorite secondary minerals include jarosite gypsum goethite amorphous fe iii oxides and fe ii al sulfate salt efflorescence the mineralogy in weathered shale defines four weathered intervals on the outcrop zones a c and soil alteration of the weakly weathered shale zone a is attributed to the 40 a exposure of the shale in this zone pyrite oxidization produces acid that dissolves calcite and attacks chlorite forming gypsum jarosite and minor efflorescent salt the pre excavation active weathering front zone b is where complete pyrite oxidation and alteration of feldspar and organic matter result in increased permeability acidic weathering solutions seep through the permeable shale and evaporate on the surface forming abundant efflorescent salt jarosite and minor goethite intensely weathered shale zone c is depleted in feldspars chlorite gypsum jarosite and efflorescent salts but has retained much of its primary quartz illite and illite smectite goethite and amorphous fe iii oxides increase due to hydrolysis of jarosite enhanced permeability in this zone is due to a 14 loss of the original mass in parent shale denudation rates suggest that characteristics of zone c were acquired over 1 ma compositional differences between soil and zone c are largely attributed to illuvial processes formation of additional fe iii oxides and incorporation of modern organic matter

pedogenesis and weathering rates of a histic andosol in iceland field and experimental soil solution study abstract it is important to study the rate determining processes of chemical weathering and soil formation in volcanic islands since a significant part of the carbon fixed by chemical weathering of silicates on earth is fixed at the surface of volcanic islands these soils are fertile and much of the river suspended matter delivered to the ocean stems from these islands this study determines the factors that drive the pedogenesis of a histic andosol in western iceland soil solutions were extracted from the profile in the field from undisturbed ex situ mesocosms and from repacked laboratory microcosms concentrations of measured and calculated inorganic species in the field and experimental soil solutions were used for thermodynamic and kinetic interpretation and to calculate the weathering rates the main primary rock constituent of the 205 cm thick soil profile was basaltic glass allophane content ranged from 2 to 22 and the soil carbon content ranged from 11 to 42 mean soil solution ph value ranged from 4 to 6 with the lowest value at 80 cm depth and highest between 150 to 205 cm the high solute concentrations in soil solutions in the beginning of the microcosm weathering experiment declined faster for anions than cations under field conditions inorganic anions were supplied by marine and anthropogenic rather than pedogenic sources and hence these anions were subsequently leached out during the experimental duration when there was a limited input of anions through experimental precipitation the factor which defined the rate at which each ion was depleted from the exchange complex of the soil decreased down the soil profile the release sequence at 50 cm depth was cl na so 4 f si the si and base cations experimental weathering rate when normalized to geographical surface area are similar to or lower than those measured from river catchments in southwestern iceland the dissolved al flux was much higher from the soil when compared to the river catchments field and experimental soil solutions were all highly undersaturated with respect to basaltic glass field and mesocosm samples were supersaturated with respect to secondary allophane and imogolite while samples from the microcosms were often undersaturated with respect to allophane and imogolite predicted dissolution rate was dictated by the soil solution a h 3 a al 3 activity ratio but slowed down by up to 20 and 30 by decreasing undersaturation in field and mesocosms respectively predicted dissolution rates according to the a h 3 a al 3 activity ratio increased up to factor of 7 30 and 37 by speciating al 3 with oxalate in field mesocosms and microcosms respectively speciation with oxalate which represents the maximum effect of the dissolved organic carbon doc on dissolution rates generally had more effect near the surface than at deep levels in the soil profile this study shows that at fixed temperature reactive surface area and composition of the volcanic glass in the soil the chemical weathering rates of andosols are dictated by 1 aeolian deposition rates and drainage which affect the saturation state and the a h 3 a al 3 activity ratio 2 the production of organic anions within the soil and 3 external supply of anions capable of complexing al 3

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

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

new evidence of co2 soil degassing anomalies on piton de la fournaise volcano and the link with volcano tectonic structures insu cnrs and la reunion prefecture projet pour la quantification de l alea volcanique a la reunion

a model of diffuse degassing at three subduction related volcanoes and 13c in soil gas were measured at three active subduction related stratovolcanoes arenal and poas costa rica galeras colombia in general rn co2 and 13c values are higher on the lower flanks of the volcanoes except near fumaroles in the active craters the upper flanks of these volcanoes have low rn concentrations and light 13c values these observations suggest that diffuse degassing of magmatic gas on the upper flanks of these volcanoes is negligible and that more magmatic degassing occurs on the lower flanks where major faults and greater fracturing in the older lavas can channel magmatic gases to the surface these results are in contrast to findings for mount etna where a broad halo of magmatic co2 has been postulated to exist over much of the edifice differences in radon levels among the three volcanoes studied here may result from differences in age the degree of fracturing and faulting regional structures or the level of hydrothermal activity volcanoes such as those studied here act as plugs in the continental crust focusing magmatic degassing towards crater fumaroles faults and the fractured lower flanks

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

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

three dimensional velocity structure of the kilauea caldera hawaii high resolution velocity models 0 5 km resolution of the kilauea caldera region are obtained by the tomographic inversion of both p and s wave arrival times data are from the permanent hawaiian volcano observatory hvo seismic network a broadband seismic network and a temporary array of stations centered on the southern boundary of the caldera a low velocity p wave anomaly is imaged centered on the southeastern edge of the caldera with a velocity contrast of about 10 and a volume of 27 km the vp vs model mimics the spatial extent of the p wave anomaly but is partitioned into two discrete anomalous volumes centered on the southern boundary of the caldera and on the upper east rift of the volcano the corresponding poisson s ratio in these zones is high 0 25 0 32 which is consistent with a densely cracked hot volume which may contain partial melt the large scale features of the models are consistent with results obtained from an earlier larger scale 2 km resolution tomographic image of kilauea volcano based on hvo network data

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

the role of phytolith formation and dissolution in controlling concentrations of silica in soil solutions and streams abstract by integrating the results of recent studies on the concentration and flux of si in european forest soils podzols and acid brown soils with published evidence on the amounts of si cycled through forest vegetation we conclude that phytoliths must be the principal immediate source and sink of silica in soil solution although mineral weathering is the ultimate source during the growing season forest vegetation takes up most of the si made available by weathering of soil minerals and by phytolith dissolution and converts it into phytoliths phytoliths will be the principal source of si leached from the soil during winter rains and spring snowmelt this work accounts for the plateau concentrations of si observed in laboratory equilibrations of bs horizon soils for the maximum si concentration reported for b horizons in the field for a deep sink for si in bs horizons and for the fact that the concentrations of si in soil drainage water and in streams all fall in or below the range expected for phytolith solubility concentrations of si in surface horizons can exceed these levels during droughts the common assumption that the concentration of si in soil solution is a result of a dynamic balance between si released by mineral weathering and that lost by leaching is untenable for bs horizons

anomalous soil co2 degassing in relation to faults and eruptive fissures on mount etna sicily italy the relationships between soil gas emissions and both tectonic and volcano tectonic structures on mt etna have been studied the investigation consisted of soil co2 flux measurements along traverses orthogonal to the main faults and eruptive fissures of the volcano anomalous levels of soil degassing were found mainly in coincidence with faults whereas only 49 of the eruptive fissures were found to produce elevated co2 soil fluxes this result suggests that only zones of strain are able to channel deep gases to the surface according to this hypothesis several previously unknown structures are suggested based on our geochemical data new structural maps of different areas of etna are proposed the soil co2 fluxes observed in this study are higher than those measured in a 1987 study and they are consistent with the higher level of volcanic unrest during the current study

imaging the crustal magma sources beneath mauna loa and kilauea volcanoes hawaii three dimensional seismic p wave traveltime tomography is used to image the magma sources beneath mauna loa and kilauea volcanoes hawaii high velocity bodies 6 4 km s in the upper 9 km of the crust beneath the summits and rift zones of the volcanoes correlate with zones of high magnetic intensities and are interpreted as solidified gabbro ultramafic cumulates from which the surface volcanism is derived the proximity of these high velocity features to the rift zones is consistent with a ridge spreading model of the volcanic flank southeast of the hilina fault zone along the south flank of kilauea low velocity material

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

initial observations from the lunar orbiter laser altimeter lola as of june 19 2010 the lunar orbiter laser altimeter an instrument on the lunar reconnaissance orbiter has collected over 2 0 10 9 measurements of elevation that collectively represent the highest resolution global model of lunar topography yet produced these altimetric observations have been used to improve the lunar geodetic grid to 10 m radial and 100 m spatial accuracy with respect to the moon s center of mass lola has also provided the highest resolution global maps yet produced of slopes roughness and the 1064 nm reflectance of the lunar surface regional topography of the lunar polar regions allows precise characterization of present and past illumination conditions lola s initial global data sets as well as the first high resolution digital elevation models dems of polar topography are described herein

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

fluid flow and water rock interaction in the east rift zone of kilauea volcano hawaii the east rift zone of kilauea volcano in hawaii represents a major area of geothermal activity fluid inclusion and stable isotope analyses of secondary hydrothermal minerals in core samples from three scientific observation holes soh drilled into the rift zone indicate that the geothermal system is dominated by meteoric waters to depths of as much as 1500 m below sea level calculated 18o and d values for fluids on the north side of the rift zone indicate that the deep meteoric fluids may be derived from precipitation on the upper slopes of mauna loa volcano in the interior of the rift zone recharge is dominated by seawater mixed with local meteoric water water rock ratios in the rift area are approximately 2 but strongly 18o enriched fluids in the deeper parts of the soh 2 and soh 4 drill holes on the north side of the rift indicate that the fluids underwent extensive interaction with rocks prior to reaching this part of the rift zone marine carbonates at the subaerial to submarine transition between 1700 and 1780 m depth in soh 4 have not fully equilibrated with the fluids suggesting that the onset of hydrothermal activity in this area was relatively recent 2000 years this may represent increased volcanic activity along the rift after the end of the ai la au phase of eruptive activity at the kilauea summit approximately 1000 years ago or it may reflect progressive evolution of the hydrothermal system in response to southward migration of intrusive activity within the rift

geochemical investigations applied to active fault detection in a volcanic area the north east rift on mt etna sicily italy geochemical investigations were performed on the northeast rift of mt etna a prominent volcanic structure of this volcano low temperature fumaroles were found on the upper part of this area and the isotopic compositions of c co2 and he suggest a likely magmatic origin of the emitted gases on the contrary very low degassing was found in the lower part of the ne rift with co2 concentrations generally very close to those in air this pattern is probably due to sealing of the eruptive fissures by the repeated injections of magma solidified into dikes and by consequent shallow hydrothermal alteration of the fissured rocks due to residual magma degassing high soil co2 concentrations were also found in an elongated area parallel to the ne rift and located immediately to the east of it the geometry of these anomalies suggests the existence of several hidden faults sub parallel to the ne rift and likely connected to the pernicana fault system this latter structure seems to merge with the ne rift at the altitude where the fumarole emissions are located the hidden structures together with the pernicana system and the ne rift represent the western and northern boundaries of a large eastward collapsing sector of mt etna

comparing volcanic glass shards in unfertilised and fertilised andisols derived from rhyolitic tephras new zealand evidence for accelerated weathering and implications for land management abstract enhanced weathering associated with the use of phosphate fertilisers has been identified in some of the major farming areas of new zealand and an evaluation of its effects on soil properties and the implications for soil management are needed we assessed changes in the character of volcanic glass shards in topsoils 0 10 cm depth of two tephra derived andisols of differing ages udivitrands hapludands and with and without long term fertilisation to test if fertilising accelerates the weathering of soil constituents using visual assessment based on scanning electron microscopy and electron microprobe analyses of glass shards from samples from paired sites we showed that the average sizes of the shards and the sharpness of the glass shard edges angularity diminished with the age of the soil and that these decreases were more marked in the soils that had been fertilised silica polymorphs were observed only in the older soil hapludand that had been fertilised we concluded that the addition of phosphate containing fertiliser enhanced the dissolution of volcanic glass consistent with phosphoric acid and f induced dealumination and desilication and thus soil weathering has been accelerated the al and si may subsequently coprecipitate as secondary minerals such as allophane however silica polymorphs may form where al activity is low the occurrence of neogenic silica in topsoils despite high annual rainfall that should result in desilication of the topsoil and reprecipitation of silica deeper in the soil is explained by the seasonality of fertiliser application and the spring summer climate where the soil remains moist for periods sufficiently long enough for the dissolution of volcanic glass and possibly of other aluminosilicates the formation of al humus complexes and the subsequent precipitation of silica in dry periods implications of the accelerated weathering for soil and land management are discussed

ten years of soil co2 continuous monitoring on mt etna exploring the relationship between processes of soil degassing and volcanic activity 1 the measurement of soil co2 flux variations is a well established practice in many volcanic areas around the world until recently however most of these were made using direct sampling methods these days a variety of automatic devices providing real time data now make the continuous monitoring of volcanic areas possible a network of automatic geochemical monitoring stations etnagas network was developed by ingv palermo and installed at various sites on the flanks of mt etna here we present a large set of soil co2 flux data recorded by the network dating back 10 years a period in which several noteworthy eruptive phenomena occurred our statistical analysis strongly suggests that anomalous measurements of soil co2 flux are attributable to volcanic origin and in almost all cases precede volcanic activity here we present the actual data series recorded by etnagas and an interpretative model of the expected behavior of soil co2 flux in terms of increase decrease cycles which corresponded well with the volcanic activity during this period through the use of a comparative approach incorporating both volcanological and geochemical data the global soil co2 flux trends are put into a coherent framework highlighting close links between the time flux variations and volcanic activities these insights made possible from 10 years of uninterrupted data confirm the importance of continuous monitoring of volcanic soil degassing and may contribute in the forecasting of imminent eruptive activity or the temporal evolution of an in progress eruption therefore facilitating civil defense planning in volcanic areas under high hazard conditions

weathering sequence of soils from volcanic ash involving allophane and halloysite new zealand abstract the clay minerals in a series of soils from rhyolitic ash having the same stratigraphy but different leaching environments were estimated quantitatively by oxalate dissolution infrared spectroscopy differential thermal analysis electron microscopy and x ray diffraction three soils were studied in detail these were the kereone soil mean annual rainfall 1200 mm the ohaupo soil 1400 mm and the mairoa soil 2600 mm the kereone soil contained halloysite as the predominant clay mineral whereas the mairoa soil was mainly allophanic the ohaupo soil contained considerable amounts of both allophane and halloysite thus the allophane content of the soils increased as rainfall increased reflecting a sequence of increased l leaching the si concentration in soil solution decreased as rainfall increased also reflecting increasing leaching of the soils at mairoa si is rapidly removed and allophane al si 2 1 with monomeric silicate is formed whereas at kereone less leaching occurs si levels are higher and halloysite al si 1 1 with polymeric silicate is formed at intermediate sites either allophane or halloysite may form the often reported situation of younger allophanic beds overlying older 10 000 year halloysitic beds may not be due to allophane weathering to halloysite but may result from lower temperature and drier climate during the last glacial maximum between 10 000 and 26 000 years before present bp a new weathering scheme for volcanic ash in new zealand is presented

a micromorphological study of pedogenic processes in an evolutionary soil sequence formed on late quaternary rhyolitic tephra deposits north island new zealand abstract the influence of time as a soil forming factor was studied on an evolutionary sequence of five soils 1850 radiocarbo years bp ca 120 000 bp developed in rhyolitic tephra deposits in new zealand new micromorphological observations were combined with existing macromorphological chemical textural and clay mineralogical analyses to assess the extent of polygenesis in the soils the younger soils 1850 bp to ca 22 600 bp are characterised by initial weathering and little secondary mineral formation this status is expressed by abundant pumice fragments and fresh easily weatherable minerals as well as a low clay content with an isotropic character comminution and neoformation are the main pedological processes the older soils ca 120 000 bp are characterised by a high degree of alteration of primary minerals little or no pumice fragments clay illuviation gleying and a high clay content 80 consisting of a range of crystalline clay minerals including halloysite gibbsite kaolinite and vermiculite plus crystalline iron oxides evidence of polygenesis can be observed in the micromorphology of the older soils 1 the range of secondary minerals is the result of the integration and succession of soil forming processes through time 2 the accumulatory character of the tephra deposits has resulted in stronger weathering of the lower horizons than upper horizons because of continuous pedogenesis such polygenesis in the older soils supports the view that the older the soil the more polygenetic it is likely to be

a continuous 5300 yr holocene cryptotephrostratigraphic record from northern new zealand and implications for tephrochronology and volcanic hazard assessment a continuous 5280 calendar cal yr long cryptotephrostratigraphic record of a peat core from northern new zealand demonstrates that cryptotephra studies can enhance conventional tephra records by extending the known distribution of ash fall and enabling re assessment of volcanic hazards a systematic sampling strategy was used to locate peaks in glass shard concentrations and to determine loci of individual geochemical populations and a palynological method involving spiking samples with lycopodium spores was adapted to facilitate accurate counting of glass shard concentrations using glass shard major element compositions and a core chronology based on eight ams 14c ages and two visible macroscopic tephra layers taupo tephra unit y 1688 1748 cal bp and tuhua tephra 6800 7230 cal bp 2cr age ranges four cryptotephras were correlated with known eruptions whakaipo unit v 2743 2782 cal bp stent unit q 4240 4510 cal bp and unit k 4970 5290 cal bp erupted from taupo volcanic ce

direct evidence of the feedback between climate and weathering long term climate moderation is commonly attributed to chemical weathering the higher the temperature and precipitation the faster the weathering rate weathering releases divalent cations to the

subsurface structures of large volcanic complexes on the nearside of the moon a view from grail gravity abstract the lunar nearside large volcanic complexes such as the rumker hills aristarchus plateau and marius hills are likely sites of intense and sustained magmatic activity these volcanic complexes recently proposed to be shield volcanoes are generally located at regionally high elevations and some feature relatively well localized positive gravity anomalies applying localized spectral analyses on high resolution gravity data obtained from the gravity recovery and interior laboratory grail mission and topography data returned from the lunar reconnaissance orbiter lro spacecraft we study the subsurface structures of these volcanic complexes the gravity signal is predicted using a thin elastic lithospheric model that considers both surface and subsurface loads best fit crustal and load densities show that the topographic highs of rumker hills marius hills gardner and kepler are mainly composed of material that has a density of more than 2850 kg m 3 which is consistent with that of emplaced igneous rocks both the aristarchus plateau and hortensius have relatively lower crustal and surface load densities with mean values around 2550 kg m 3 which are well consistent with the average bulk density of the lunar highland crust these results together with evidence of multiple volcanic edifices on the surface suggest that the shallow crusts of the rumker hills marius hills gardner and kepler are mainly composed of dense intrusive extrusive magmatic units and those of the aristarchus plateau and hortensius are mainly composed of low density materials with only small amounts of superimposed volcanic material to further constrain the subsurface structures beneath these volcanic complexes we analyze the bouguer gravity anomalies for these regions results show that dense materials that might be solidified intrusions exist beneath rumker hills marius hills gardner and prinz but no substantial dense materials have been detected beneath the aristarchus plateau hortensius kepler or cauchy the different subsurface structures among these large volcanic complexes suggest that the volcanism style at the lunar nearside is different from each other even for those formed at the same geological time

large shield volcanoes on the moon 1 the volcanic style of the moon has long been understood to consist almost exclusively of flood basalts erupted from fissures along with minor pyroclastic activity large central vent shield volcanoes that characterize basaltic volcanism on the other terrestrial planets appeared to be absent small few kilometers diameter central vent constructs have long been recognized in the lunar maria and often are found clustered in fields throughout the lunar maria new global topographic data from the lola and lroc instruments on lro reveal that almost all of these volcanic complexes on the moon occur on large regional topographic rises in the lunar maria tens to hundreds of kilometers in extent and between several hundred to several thousand meters high we propose that these topographic swells are shield volcanoes and are the lunar equivalents of the large basaltic shields found on the earth venus and mars the newly recognized lunar shields are found peripheral to the large deeply flooded impact basins imbrium and serenitatis suggesting a genetic relation to those features loading of the lithosphere by these basalt filled basins may be responsible for inducing a combination of flexural and membrane stress inducing a pressure distribution on vertically oriented dikes favorable to magma ascent this condition would occur in a zone annular to the large circular loads produced by the basins where the shield volcanoes occur

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

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

the character of long term eruptions inferences from episodes 50 53 of the pu u ō ō kūpaianaha eruption of kīlauea volcano the pu u k paianaha eruption on the east rift zone of k lauea began in january 1983 the first 9 years of the eruption were divided between the pu u 1983 1986 and k paianaha 1986 1992 vents each characterized by regular predictable patterns of activity that endured for years in 1990 a series of pauses in the activity disturbed the equilibrium of the eruption and in 1991 the output from k paianaha steadily declined and a short lived fissure eruption broke out between k paianaha and pu u in february 1992 the k paianaha vent died and 10 days later eruptive episode 50 began as a fissure opened on the uprift flank of the pu u cone for the next year the eruption was marked by instability as more vents opened on the flank of the cone and the activity was repeatedly interrupted by brief pauses in magma supply to the vents episodes 50 53 constructed a lava shield 60 m high and 1 3 km in diameter against the steep slope of the pu u cone by 1993 the shield was pockmarked by collapse pits as vents and lava tubes downcut as much as 29 m through the thick deposit of scoria and spatter that veneered the cone as the vents progressively lowered the level of the pu u pond also dropped demonstrating the hydraulic connection between the two the downcutting helped to undermine the prominent pu u cone which has diminished in size both by collapse as a large pit crater formed over the conduit and by burial of its flanks intervals of eruptive instability such as that of 1991 1993 accelerate lateral expansion of the subaerial flow field both by producing widely spaced vents and by promoting surface flow activity as lava tubes collapse and become blocked during pauses

fingerprints and age models for widespread new zealand tephra marker beds erupted since 30 000 years ago a framework for nz intimate abstract the role of tephras in the nz intimate project is a critical one because most high resolution palaeoclimatic records are linked and dated by one or more tephra layers in this review first we document eruptive distributional and compositional fingerprinting data both mineralogical and geochemical for 22 key marker tephras erupted since 30 000 years ago to facilitate their identification and correlation we include new glass compositional data the selected marker tephras comprise 10 from taupo and nine from okataina volcanoes rhyolitic one from tuhua volcano peralkaline rhyolitic and one each from tongariro and egmont volcanoes andesitic second we use four approaches to develop 2 age models for the tephras youngest to oldest 1 calendar ages for kaharoa and taupo y were obtained by wiggle matching log derived tree ring sequences dated by 14c 2 whakaipo v was dated using an age depth model from peat 3 14 tephras in the montane kaipo peat sequence waimihia s unit k whakatane tuhua mamaku rotoma opepe e poronui c karapiti b okupata konini waiohau rotorua rerewhakaaitu were dated by simultaneously wiggle matching stratigraphic position and 51 independent 14c age points against intcal04 using bayesian probability methods via both oxcal and bpeat and 4 the five oldest tephras erupted before ca 18 000 cal yr bp were dated by calibrating limited numbers of 14c ages using intcal04 okareka or comparison curves of the expanded cariaco basin sequence te rere kawakawa oruanui poihipi okaia kawakawa oruanui tephra the most widely distributed marker tephra was erupted probably ca 27 097 957 cal yr bp potential dating approaches for the older tephras include their identification in antarctic ice cores if present or annually laminated sediments for which robust calendar age models have been constructed high precision ams 14c dating on appropriate material from environmentally stable sites systematic luminescence dating or new radiometric techniques e g u th he if suitable minerals are available and errors markedly reduced further application of bayesian age modelling to stratigraphic sequences of 14c ages possibly augmented with luminescence ages may help refine age models for pre holocene tephras with the largest errors finally we discuss the critical role these marker tephras play in the ongoing construction of an event stratigraphy for the new zealand region which is a key objective of australasian and southern hemisphere intimate projects