preseismic hydrogen gas anomalies caused by stress corrosion process preceding earthquakes simultaneous monitoring of he h2 ar n2 ch4 and rn in gas bubbles of groundwater from the 1 500 m deep nagashima well in the active yoro fault zone central japan reveals that three microearthquakes with m 1 6 2 6 in the fault zone are accompanied and preceded by increases of h2 as is a moderately large event with m 5 4 in the same fault zone all the focal distances of the earthquakes are within 25 km no comparable anomalies were seen in the gas species other than h2 we suggest that the selective and preseimic increases of h2 in groundwater gas bubbles are geochemical signals of the earthquake nucleation process of stress corrosion mechanism aseismic slips preceding earthquakes in the active fault zone are likely to have enhanced h2 production by mechanochemical reaction of fractured rock surface with water in pre existing fault planes as groundwater conduits

co 2 degassing in the hartousov mofette area western eger rift imaged by co 2 mapping and geoelectrical and gravity surveys strong subcontinental mantle dominated co2 degassing occurs in the hartousov and bublak mofette fields in the western eger rift the combination of co2 gas flux and soil gas measurements as well as gravity and geoelectric surveys provides insight into the surface and subsurface of this unique mofette area co2 soil gas and gas flux measurements reveal that large amounts of carbon dioxide are released via channels with diameters below 1 m carbon dioxide emissions of several tens and up to more than 100 kg day 1 are ejected via these small seeps measurements with small spacings are necessary to account for the point like focused gas discharge in the lesser degassing surrounding we estimate that between 23 and 97 tons of co2 are released over an area of about 350 000 m2 each day in the hartousov mofette field the application of widely used geostatistical tools leads to estimations of the co2 discharge with very high standard deviations due to the strong positive skewness of the data distribution geophysical investigations via electrical resistivity tomography and gravity measurements were carried out over areas of strong seepage and reveal distinct anomalies in the subsurface below mofettes indicating rock and sediment alterations and or sediment transport by pressurised ascending co2 and water mobilised by it this study reveals that the gas emanations only occur west of a morphological step which is related to a n s oriented fault zone the pocatky plesna fault zone the results of co2 mapping and the geophysical studies can track the course of this fault zone in this area our results fit into a tectonic model in which the mofette fields are in the centres of two independent pull apart basin like structures we hypothesise that the sinistral strike slip movement of the pocatky plesna fault zone leads to a pull apart basin like opening at which the strong mantle derived co2 degassing occurs nowadays since the hartousov and bublak mofette fields only illustrate examples along the n s striking pocatky plesna fault zone its role and other n s striking faults roles of the regensburg leipzig rostock zone for upper mantle degassing might have been underestimated previously

seismically induced changes of the fluid signature detected by a multi isotope approach he co2 ch4 n2 at the wettinquelle bad brambach central europe 1 we present a study considering the systematics of gas and isotope compositions 3 he 4 he 13 c co2 13 c ch4 15 n of a permanent magmatic co 2 flux in the hydrothermal system of the spring wettinquelle in bad brambach and their relation to the seismic activity beneath the western eger rift the gas and isotope compositions were monitored for more than 3 years the time series includes periods before during and after a 4 month long seismically active period from the end of august to the end of december 2000 shifts due to admixture of crustal components were found for all monitored isotope ratios during and after the seismically active period in case of helium and nitrogen isotopic anomalies occurred already about 6 weeks before the beginning of the seismically active period contemporaneous with a water level anomaly of the well vl4 near the wettinquelle on the one hand preseismic deformations may be responsible for the observed isotope anomalies on the other hand coseismic fracturing processes in the surroundings of the hypocenters may play a role both effects produce greater permeability and result in the release of crustal fluids the migration and admixture of these crustal components to the permanent upper mantle derived fluid flux result in geochemical anomalies that persist for more than 2 years the results of the detailed isotope monitoring have proven to be an important contribution to understand the geodynamic processes that may presently be going on in the region vogtland nw bohemia

crustal deformations in the epicentral area of the west bohemia 2008 earthquake swarm in central europe 1 in west bohemia central europe during october 2008 an earthquake swarm of 25 000 shocks with a maximum event of ml 3 7 3 8 occurred at depths of 7 11 km in 2007 annual gps campaigns were launched during the co seismic phase displacements of a few centimeters were detected at gps sites maximum displacement was revealed at the kopa site which subsided by 167 mm the epicentral area is covered by eluvium of 4 10 m thick and is located in undulating pastures and well forested valleys where visible surface soil effects could not be observed to test possible fault manifestations rough geomorphologic geoelectric and geochemical surveys were performed gps and seismic data with geologic materials were used to build a forward model for surface displacements crustal deformations and shear and normal stress fields the fields enabled us to better determine crustal deformations and stresses that appeared within the seismic cycle during the pre co and post seismic phases during the co seismic phase modeled fault motions along n s faults located within the epicentral zone reached 0 6 1 mm day possible structural block rotations were comprised of these motions a dominant role for stress accumulation release and relaxation was assigned to the marianske lazn fault zone and the nov kostel zone strain loads slowly and when local pt conditions with an action of deep magmatic fluids reach instability the strain is released and stress balancing occurs the process leads to the reversible motions known for silent earthquakes a forward crustal deformation model for west bohemia is also presented within

circulation anomalies associated with tropical convection during northern winter abstract lagged cross correlations between outgoing longwave radiation olr and national meteorological center global analyses are utilized to isolate the preferred upper level and surface circulation anomalies associated with tropical convection during northern winter three intraseasonal time scales are studied 30 70 14 30 and 6 14 days in the 30 70 day band the upper level circulation signals are zonally elongated with zonal wavenumbers 0 2 dominant higher frequency signals are dominated by zonal wavenumbers 5 and 6 in the 14 30 day band convection over the eastern hemisphere is associated with upper level anticyclones in the subtropics and appears to be linked in some cases to midlatitude wave trains the strongest signals are for convection over africa australia and the eastern indian ocean only weak signals are seen for convection over indonesia in these regions of upper level easterlies olr anomalies peak prior to the maximum anomalies in wind suggesting forcing of the circulation b

discovery of the first quaternary maar in the bohemian massif central europe based on combined geophysical and geological surveys abstract based on results of previous investigations of tephra tuff volcaniclastic deposits and a geophysical survey in the surroundings of the elezna h rka quaternary volcano west bohemia we performed detailed geophysical surveys using gravimetry magnetometry and electrical conductivity techniques striking anomalies were revealed in a morphological depression near m tina west bohemia as a strong evidence of the assumed maar diatreme structure the sharp isometric gravity low of 2 30 mgal as well as the corresponding positive magnetic anomaly of 200 nt with a negative rim on its northern side indicate a steeply dipping geological body of low density and containing magnetic rocks minerals magnetic survey also showed pronounced local anomalies outside the depression that can reflect relicts of the tephra rim of the maar this geophysical evidence was then proven by an exploratory drilling near the centre of the gravity anomaly macroscopic on site evaluation of the core and more detailed sedimentological petrochemical palynological and microbiological laboratory analyses further confirmed the existence of a maar structure filled by 84 m of lake sediments reflecting a succession of several warm and cold climatic periods results of palynological analyses confirm the presence of a continuous palaeoclimate archive with at least three successive warmer periods of most probably interstadial character from the upper quaternary saalian complex therefore the recovered sediment sequence holds strong potential for in depth paleoclimate reconstruction and deep biosphere studies at the bottom of the m tina 1 my 1 borehole 84 85 5 m country rock debris was found containing also volcanic bombs and lapilli the discovered volcanic structure is considered to be the first known quaternary maar diatreme volcano on the territory of the bohemian massif because of hidden active magmatic processes in combination with earthquake swarm seismicity ca 20 30 km north of the m tina maar reconstruction of the palaeovolcanological evolution is important for evaluation of hazard potential of the ne and e part of the cheb basin

co 2 co fluid inclusions in a composite peridotite xenolith implications for upper mantle oxygen fugacity fluid inclusions occur in a composite xenolith from the lunar crater volcanic field nevada u s a the xenolith is an amphibole bearing wehrlite that is cut by an andesine amphibole vein the compositions of individual fluid inclusions in both portions of the xenolith have been determined using microthermometry and micro laser raman spectroscopy fluids in the host wehrlite are nearly pure co2 99 mol whereas those in the vein contain from 8 5 to 12 0 mol co in co2 chemical modelling shows that the composition of the vein fluids at t room is representative of the composition at the high p t conditions of trapping graphite has not been observed by optical microscopy in any of the fluid inclusions graphite is probably absent although stable at t 800 c most probably because of the kinetically unfavorable co decomposition reaction and rapid quenching by combining the measured fluid compositions with fluid p v t data and the chemical equilibrium co2 co 1 2 o2 we have calculated the oxygen fugacity of the fluid inclusions at 1200 c log f o 2 8 6 vein and 6 host if the f o 2 of the fluid in the vein represents that in equilibrium with the magma that crystallized to produce the vein then the f o 2 of the basalt magma is near qfm at 1200 c and 10 3 kbar this is similar to values reported for extrusive basaltic lavas if the much lower intrinsic oxygen fugacity values for divines and spinels from alkali basalt nodules are representative of upper mantle conditions then oxidation of basaltic magmas must occur in the upper mantle prior to ascent to the surface implications for the origin of co2 rich fluids and carbon isotope geochemistry are also discussed

a stress forecast earthquake with hindsight where migration of source earthquakes causes anomalies in shear wave polarisations abstract the stress aligned shear wave splitting observed throughout most of the crust is a three dimensional function of the effective elastic anisotropy of distributions of fluid saturated grain boundary cracks and preferentially oriented pores fluid saturated microcracks are highly compliant and crack geometry responds readily to changes in stress monitoring with shear wave splitting allows the accumulation of stress before earthquakes to be recognised and the time and magnitude of the impending earthquake to be stress forecast such increases in stress have been observed some 15 times with hindsight and one successful real time stress forecast here we report a further with hindsight stress forecast in northern iceland where increases of time delays implying stress accumulation are observed before a 4 9 earthquake at two seismic stations at epicentral distances of 50 km and 92 km there are however two anomalies changes in shear wave polarisations at the nearest station appear to be due to migration of shear wave source earthquakes in a uniform anisotropic symmetry into ray path directions with different anisotropic shear wave polarisations such directional changes in shear wave polarisations are occasionally observed above small earthquakes and may be misinterpreted as structural or temporal changes in anisotropy a further anomaly is that the station at 92 km displays variations in time delays but a station just 4 km farther away on the other side of a major fault appears to be in the stress shadow of the fault and does not display temporal variations despite having adequate source data

monitoring of hydrogen along the san andreas and calaveras faults in central california in 1980 1984 hydrogen h2 has been monitored continuously at 1 5 m depth at nine sites along the san andreas and calaveras faults in central california since december 1980 site characteristic small noninstrumental diurnal variations were recorded during quiescent periods at most sites abrupt h2 changes were observed concurrently at two sites on the calaveras fault some of these were correlated with oscillatory fault slips large 1000 4000 ppm h2 increases were recorded at some sites on the san andreas fault between july 1982 and november 1983 which may be correlated with eleven m 5 earthquakes that occurred near coalinga during this period we attribute both the h2 increases and the triggering of the earthquakes to a large scale compressive stress field within the ductile mafic crust near the plate boundary the stress perhaps caused bulging of the base of the brittle upper crust and thus caused dilation of the san andreas fault zone allowing the escape of pent up h2 generated by hydration reaction of the mafic crust at the same time mobile serpentinites may have squeezed into the seismogenic fault beneath the coalinga area triggering the earthquakes

source to sink analysis of continental rift sedimentation triassic cuyo basin precordillera argentina abstract the northernmost outcrops of the triassic extensional cuyo basin in western argentina reveal a basal coarse conglomerate overlain by a thinning fining upward siliciclastic red bedded section with subordinated tuffs and microbial rich carbonates cerro puntudo formation unconformably covered by a second coarse conglomerate el relincho formation which were previously interpreted as two rifting events an integrated analysis of facies associations stacking patterns paleocurrent and provenance was carried out in order to reveal the rift sedimentation using a source to sink approach besides the traditional controls in continental basins e g sedimentation tectonics and climate this study considers possible drainage pattern evolution in order to differentiate isolated versus integrated depocenter stages u pb zircon data corroborate our analysis and reveal a volcanic basement source of 256 8 3 5 ma permian lopingian and a sedimentation age of 249 8 2 5 ma early triassic for a tuff interbedded within the cerro puntudo formation complementing previous age of 243 8 1 9 ma middle triassic at the top of this unit stratigraphic stacking allows the interpretation of three evolutionary stages a first stage represented by thick massive boulder volcanic rich conglomerates characterizing alluvial fan deposition indicates strong tectonic activity of border faults first rifting event these features suggest high surface gradient and high available space controlling accommodation and dispersal of gravity and debris flow deposits paleocurrents to the east reveal largely north south normal faults located to the west and sediment supply from a proximal volcanic source area a second stage represented by a notable fining thinning upward facies including fluvial and palustrine stromatolites with pedogenetic features deposits indicates a transition to tectonic quiescence these facies associations developed in a context of low sedimentation rate limited tectonic relief and low accommodation space a third stage is represented by greenish well rounded coarse grained polymictic conglomerates of el relincho formation that unconformably truncate the cerro puntudo formation these conglomerates are interpreted as perennial braided fluvial systems with paleocurrents to the northwest indicating drainage reorganization primarily influenced by climate change and combined tectonic reactivation previously considered the second rifting event climate change affected sediment delivery and allowed regionally connectivity and overfilling of the depocenters in this last stage northwest axial transport from variable sources within the precordillera to the southeast is inferred from provenance analysis indicating open linked depocenters this study suggests a new stratigraphic correlation for the northern part of the cuyo basin implying that during the first rifting event a semi arid climate prevailed with development of isolated and independent depocenters first and second stages whereas above the unconformity initiating the second rifting event third stage depocenters were interconnected in the light of our source to sink analysis such paleogeographic change allowed overfilling and laterally linkage of separate half grabens along the cuyo basin whereas tectonic reactivation may better explain renewed conglomerate deposition climate change toward more humid conditions allowed previously separated depocenters to be connected through axial drainages

carbon dioxide earth degassing and seismogenesis in central and southern italy 1 we present the first regional map of co2 earth degassing from a large area most of central and south italy derived from the carbon of deep provenance dissolved in the main springs of the region the investigation shows that a globally significant amount of deeply derived co2 10 of the estimated global co2 emitted from subaerial volcanoes is released by two large areas located in western italy the anomalous flux of co2 suddenly disappears in the apennine in correspondence to a narrow band where most of seismicity concentrates here at depth the gas accumulates in crustal traps generating co2 overpressurized reservoirs which induce seismicity

monitoring of helium and carbon isotopes in the western eger rift area czech republic relationships with the 2014 seismic activity and indications for recent 2000 2016 magmatic unrest abstract we report new data of the regional distribution pattern of total gas compositions as well as he and co2 isotopic compositions from 25 gas exhalations in the western eger rift and its surroundings additionally the first time series data from gas exhalations in a clay pit within the cheb basin cb are given at 21 degassing locations the first data were obtained 20 years ago from 7 locations within the degassing center cb and from 3 degassing sites belonging to the marianske lazn ml degassing center neon and argon isotope compositions were determined also co2 is the major component at all degassing sites the 13c values display a small range 1 7 to 5 1 and the 3he 4he ratios vary from 1 9 to 5 9 ra the highest 3he 4he ratios are found at locations along the pocatky plesna fault zone followed by the degassing site in the clay pit on the nova ves fault and the locations on the ml fault at the edge of the cb although gas flow and co2 concentrations in all degassing centers are very high the fractions of mantle derived helium are different with presently up to 94 in relation to the sclm 3he 4he of 6 32 ra in the cb up to 73 in the ml and up to 35 in the karlovy vary degassing center at the locations in the eastern part of the cb a clear progressive increase of the 3he 4he ratio has been observed since the first sampling campaigns there in 1993 and 1994 whereas at the other degassing sites the helium isotope ratio remained essentially the same the progressive increase of the 3he 4he ratio in the eastern part of the cb together with further short time increases up to 6 3 ra at one location bublak before both the 2000 and 2008 earthquake swarms indicate an ongoing magmatic process beneath this area which seems to be associated with the occurrence of seismicity the cb is located close to the nov kostel focal zone where since the beginning of our investigations four strong periods of seismicity with magnitudes 3 occurred the latest gas data confirm our earlier findings time series studies showed that in relation with seismic events decreased 3he 4he ratios were repeatedly observed due to admixed seismically released crustal helium presently the eastern part of the cb is the most active non volcanic region in the european cenozoic rift system with gas signatures similar to those found in free mantle derived gases from the east african rift system

monthly monitoring of gas and isotope compositions in the free gas phase at degassing locations close to the nový kostel focal zone in the western eger rift czech republic abstract we report new data on gas and isotope compositions of mantle derived exhalations from five locations in the vogtland germany nw bohemia czech republic area close to the nov kostel focal zone recorded by monthly sampling of gases over a three year period this region is the locus typicus for the term earthquake swarm since 1985 86 the largest numbers of earthquake swarms in the vogtland nw bohemia have occurred in the nov kostel focal zone mantle derived degassing has been studied at four locations within the cheb basin degassing centre and at the wettinquelle spring to the north on the edge of the cheb basin the bublak and u mostku locations are on the pocatky plesna fault zone ppz while the kopanina and dolni castkov locations are on the marianske lazn fault mlf the mantle derived helium content at locations along the ppz covers the range of the sub continental lithospheric mantle sclm along the mlf the 3 he 4 he ratios are with up to 5 4 ra a little bit lower as at the ppz locations the co 2 3 he ratios point to a predominantly magmatic source depending on the magnitude of gas flux the monthly sampling results indicated various major influences on the fluid signatures at the monitored locations due to seasonal cycles based on the different strong influence of co 2 water interaction micro seismicity occurred repeatedly during the monitoring period and seismically triggered geochemical anomalies were repeatedly observed at the locations close to the focal zone the 3 he 4 he ratios drop from 5 9 ra mean up to 5 6 ra at bublak and from 5 6 ra up to 5 3 ra at u mostku a decrease in 3 he 4 he ratios was observed prior to seismic events due to stress accumulation before rupturing and also after the events due to the release of crustal derived components within the area of the focal zone due to the higher helium baseline content of the kopanina gas the 3 he 4 he ratios decreased there only from 4 6 to 4 5 ra at the wettinquelle the most distant from the focal zone the 3 he 4 he ratios ranged between 2 3 and 2 5 ra altogether superimposed to the seismically induced anomalies a clear three month lasting increase of mantle derived helium was observed at the locations on the ppz the 3 he 4 he ratios increased to 6 3 ra at bublak and to 6 0 ra at u mostku an increase in the 3 he 4 he ratios was also noted at kopanina to 4 7 ra and dolni castkov to 5 4 ra interpreted as indicating an ascent of less degassed magma dyke intrusions from the deeper lithospheric mantle reservoir superimposed geochemical effects initiated by the temporal and spatial evolution of a hidden magmatic driven geodynamic process have therefore been observed in a continental rift system for the first time

nitrogen in future biosphere studies this article suggests a theme for future nitrogen studies involving the functioning and evolution of the biosphere together with certain aspects of human biology it is hoped that this theme could be developed into a multi authored book at some point in the future although numerous new case studies may be required the biosphere can be considered to be a single interactive system comprised of numerous component parts including the atmosphere rain rivers lakes oceans continental ecosystems marine ecosystems soils and sediments in order to study the internal complexity of each of the components and the relationships that exist between them one can choose a common theme the author believes that nitrogen is a good prospect because of its ubiquitous nature and complex chemistry the burial of sedimentary volatiles in the continental crust has contributed to the long term chemical evolution of the exterior environments of the earth the most marked effects notably the accumulation of atmospheric oxygen have been due to the burial of reduced carbon an understanding of the passage of sedimentary volatiles through the crust will provide important constraints on the evolution of the biosphere and may lead to a more meaningful comparative planetology carbon is difficult to trace through crustal processes because its high temperature form graphite is incompatible with the crystal structures of silicate minerals however the high temperature form of sedimentary nitrogen ammonium readily enters into potassic minerals and it can be easily traced through crustal processes herein the fate of sedimentary nitrogen is traced from wet sediments through metamorphic rocks into granites and other crustal melts without the trapping of nitrogen in the crust and the liberation of oxygen that is a consequence of biological nitrogen fixation the n2 o2 of the atmosphere may have been about 82 9 to 16 3 and the total atmospheric pressure about 1 2 atm most of the changes in the oxygen content is due to dilution by nitrogen with only about 5 of the present atmospheric oxygen being a consequence of nitrogen fixation the ancient continental surfaces would have been volcanic deserts containing little 1 ppm or no nitrogen today nitrogen rich soils support continental ecosystems one can use nitrogen as a window to speculate on the colonisation of the continents by land plants herein nitrogen fixation by legumes is considered in detail and by drawing analogies with the present day the author speculates on the colonisation of the continents by land plants having speculated on the co evolution of the atmosphere soils and continental ecosystems one can place a human being in the centre of a tropical forest and begin to examine how they relate to the modern biosphere the chosen example is the metabolism of plant protein and the roles of glutamate dehydrogenase gdh vitamin b2 and flavin mononucleotide fmn the realisation of this theme would imply numerous new case studies notably those concerning the continental crust where nitrogen studies were linked to mineralogy petrology and other geochemical tracers including sr o al and k and where the short range order of 15n were taken into consideration

misr based passive optical bathymetry from orbit with few cm level of accuracy on the salar de uyuni bolivia abstract we demonstrate that under ideal circumstances passive optical measurements can yield surface water depth estimates with an accuracy of a few centimeters our target area is the salar de uyuni in bolivia it is a large active salt flat or playa which is maintained as an almost perfectly level and highly reflective surface by annual flooding to a mean depth of 30 50 cm we use misr data to estimate spatial and temporal variations in water depth during the waning portion of the 2001 flooding cycle we use a single icesat laser altimetry profile to calibrate our water depth model though the salt surface is probably the smoothest surface of its size on earth with less that 30 cm rms height variations over an area of nearly 104 km2 it is not completely featureless topography there includes a peripheral depression or moat around the edge of the salt and several sets of prominent parallel ridges with 5 km wavelength and 30 cm amplitude the process by which these features form is still not well characterized

a preliminary study of summertime tropospheric circulation patterns over south america estimated from cloud winds abstract cloud winds obtained from sms i geostationary satellite images for the southern hemisphere summer time are used to describe the tropospheric circulation over tropical and subtropical south america these data provide good spatial and temporal coverage over south america for at least two levels in the troposphere the summertime circulation derived from cloud winds is similar in pattern to that obtained from sparse conventional winds but is more intense the major features of the time averaged circulation at the upper level 300 100 mb are an intense quasi stationary anticyclone trough system extending over most of south america north of 35 s a band of easterly flow near 10 s and strong cross equatorial northward flow between 60 and 80 w longitudes at the lower level 900 700 mb the major features are the northerly and northwesterly jet type flow along the eastern slopes of the central andes and northeasterly trades over much of the remainder of the continental region to the north and cast

seismically triggered anomalies in the isotope signatures of mantle derived gases detected at degassing sites along two neighboring faults in nw bohemia central europe the vogtland and nw bohemia region is known for its earthquake swarms the most intensive swarm since 1985 86 occurred in october 2008 to find further indications for the interaction of ascending mantle derived fluids and the occurrence of earthquake swarms detailed fortnightly studies of gas compositions co2 n2 ar he h2 and ch4 and isotope ratios 13c 15n and 3he 4he were carried out between october 2008 and april 2011 at four locations close to the nov kostel focal zone and at the wettinquelle spring bad brambach from the start of the 2008 earthquake swarm seismically induced isotope geochemical anomalies were recorded at locations along the pocatky plesna fault zone ppz and were for the first time also found at degassing locations on the marianske lazn fault zone mlf variations were observed in both the temporal and spatial distributions of the anomalies as well in anomaly strengths probably due to the positions of these fault zones relative to the focal zone and to differences in fluid migration pathways prior to both the 2000 and 2008 swarms 3he 4he ratios 6 ra were recorded at the bublak mofette these anomalous pre seismic 3he 4he ratios suggest that both the 2000 and 2008 swarms may have been associated with the supply of fresh magma from a less degassed reservoir in the lithospheric mantle the temporal 13cco2 pattern from detailed studies at bublak between 2005 and 2011 indicates progressive magma degassing as well as seismically induced variations in the 13c providing additional support to the interpretation derived from the 3he 4he ratios

in stream wetland deposits megadroughts and cultural change in the northern atacama desert chile a key concern regarding current and future climate change is the possibility of sustained droughts that can have profound impacts on societies as such multiple paleoclimatic proxies are needed to identify megadroughts the synoptic climatology responsible for these droughts and their impacts on past and future societies in the hyperarid atacama desert of northern chile many streams are characterized by perennial flow and support dense in stream wetlands these streams possess sequences of wetland deposits as fluvial terraces that record past changes in the water table we mapped and radiocarbon dated a well preserved sequence of in stream wetland deposits along a 4 3 km reach of the rio san salvador in the calama basin to determine the relationship between regional climate change and the incision of in stream wetlands the rio san salvador supported dense wetlands from 11 1 to 9 8 6 4 to 3 5 2 8 to 1 3 and 1 0 to 0 5 ka and incised at the end of each of these intervals comparison with other in stream wetland sequences in the atacama desert and with regional paleoclimatic archives indicates that in stream wetlands responded similarly to climatic changes by incising during periods of extended drought at 9 8 3 5 1 3 and 0 5 ka

southern oscillation signal in south american palaeoclimatic data of the last 7000 years abstract during strong el nino events rainfall anomalies and changes in wind patterns are observed in different regions of south america along the central brazilian coast during the 1983 el nino year the frontal systems were blocked to the south provoking a reversal of the longshore sand transport long duration reversals of longshore transport were also recorded in holocene beach ridge terraces from the rio doce coastal plain this led to the formulation of a model relating these reversals of longshore transport to el nino like conditions el nino like conditions are past average climate situations that generate the same perturbations as the strong el nino events observed during the last decade they are likely to correspond to the long duration low phase of the southern oscillation to confirm this hypothesis we compared the holocene beach ridge record with other palaeoenvironmental records from regions where strong el nino events would have a substancial signal as well 1 water level fluctuations of lake titicaca 2 a pollen and sediment record in an eastern amazonian lake 3 changes of the rio xingu discharge in eastern amazonia and 4 variations of sand supply at the rio piura and rio chira outlets in the sechura desert the occurrences of el nino like conditions were numerous before 3900 3600 yr b p absent between 39003600 and 2800 2500 yr b p and infrequent after 2800 2500 yr b p

graphite bearing co2 fluid inclusions in granulites insights on graphite precipitation and carbon isotope evolution graphite in deep crustal enderbitic orthopyroxene garnet plagioclase quartz granulites 740 c 8 9 kb of nilgiri hills southern india were investigated for their spectroscopic and isotopic characteristics four types of graphite crystals were identified the first type gri which is interstitial to other mineral grains can be grouped into two subtypes gria and grib gria is either irregular in shape or deformed and rough textured with average 13c values of 12 7 0 4 n 3 a later generation of interstitial graphite grib shows polygonal crystal shapes and highly reflecting smooth surface features these graphite grains are more common and have 13c values of 11 9 0 3 n 14 both subtypes show well defined raman shifts suggesting a highly crystalline nature cores of interstitial graphite grains have on average lower 13c values by 0 5 compared to that of the rim the second type of graphite grii occurs as solid inclusions in silicate minerals commonly forming regular hexagonal crystals with a slightly disordered structure the third type of graphite griii is associated with solid inclusions up to 100 m that have decrepitation halos of numerous small 15 m satellite fluid inclusions of pure co2 with varying density 1 105 to 0 75 g cm3 the fourth type of graphite griv is found as daughter crystals within primary type co2 fluid inclusions in garnet and quartz these fluid inclusions have a range of densities 1 05 to 0 90 g cm3 but in general are significantly less dense than graphite free primary pure co2 fluid inclusions 1 12 g cm3 raman spectral characteristics of graphite inside fluid inclusions suggest graphite crystallization at low temperature 500 c the precipitation of graphite probably occurred during the isobaric cooling of co2 rich peak metamorphic fluid as a result of oxyexsolution of oxide phases the oxyexsolution process is evidenced by the magnetite ilmenite granular exsolution textures and the systematic presence of numerous micron sized rutile and other oxide inclusions in association with fluid inclusions within garnet plagioclase and quartz the carbon isotope compositions of coexisting co2 in fluid inclusions and graphite show a fractionation co2 gr co2 gr of 6 in garnet consistent with the existing theoretical estimates of co2 gr co2 gr at 800 c a subsequent generation of co2 inclusions trapped in matrix quartz and quartz segregation have higher 13c values 4 and 2 9 respectively graphite in quartz segregations also has higher 13c values 9 8 than those in enderbite 12 7 micro graphite crystals included in garnet quartz enderbite and quartz segregation have average 13c values of 11 1 10 4 and 8 7 respectively indicating progressive enrichment in 13c with a decrease in temperature of recrystallization of respective minerals this progressive enrichment is also observed in carbon isotope compositions of fluid inclusion co2 suggesting isotopic equilibrium during graphite precipitation from co2 fluids thus the carbon isotope record preserved in these rocks by the interstitial graphite co2 fluid in enderbite graphite microcrystals graphite in quartz segregation and co2 fluid in quartz segregation suggests a temperature controlled isotopic evolution this evolution is in accordance with a closed system rayleigh type graphite precipitation process which progressively enriched residual co2 in 13c

high 3he emanation and seismic swarms observed in a nonvolcanic forearc region the 3he 4he and 4he 20ne ratios of gases emergent in the southwestern part of japan have been measured by a mass spectrometer the geographical distribution pattern of the 3he 4he ratios in the kinki district a non volcanic forearc region where microseismic activity at shallow depths has continued over a long period of time is strikingly different from those found in the rest of the japanese islands including the shikoku district which lies next to kinki anomalously high 3he 4he ratios up to 9 69 10 6 are found in the kinki district all the observed phenomena high emanation of 3he of magmatic origin high temperature hot springs high terrestrial heat flow hypocentral distribution of microearthquakes a local irregularity in the dip direction of the subducting philippine sea plate and the presence of molten materials inferred from the characteristic phases of sxp and sxs reflected waves in microseismograms strongly suggest the presence of a shallow magma body beneath the area

helium degassing related to the kobe earthquake the sup 3 he sup 4 he ratios of groundwaters at nishinomiya city close to the epicenter decreased immediately after the 1995 kobe earthquake in japan while the sup 4 he sup 20 ne ratios increased the delta d and delta sup 18 o values of the groundwaters were identical before and after the earthquake apparent groundwater ages calculated by tritium sup 3 he concentrations also did not change if we correct the addition of radiogenic helium into the samples by the earthquake these observations may be attributed to following phenomenon 1 release of radiogenic he as a result of micro fracturing of rocks during the earthquake followed by degassing from the aquifer system in the amount of about 4 0 1 3 x 10 sup 9 cm sup 3 stp cm sup 3 rock 2 simple mixing of low tritium water with high radiogenic helium in the clay layer and high tritium water with atmospheric helium in the aquifer and 3 flow path mixing in the region of the sample screen if we take the 1 degassing hypothesis as a function of micro fracturing it is possible to calculate the total he degassing related to the kobe earthquake 4 x 10 sup 11 cm sup 3 stp which is about 3 of the steady state global he flux of 1 2 x 10 sup 13 cm supmore 3 stp year thus earthquake may play an important role in he degassing from the solid earth less

earthquake impact on iron isotope signatures recorded in mineral spring water we investigated the iron isotope signatures of dissolved fe in the water of the wettinquelle mineral spring bad brambach germany by time series sampling covering seismically active periods related to tectonic activity near the eger rift system in central europe our objective was to test whether fe isotopes trace earthquake induced abiotic and biotic changes in the fluid rock interaction of the deep fissured granitic aquifer we found that the dissolved fe isotope signatures in spring water are distinct from the granitic source signature 56fe 0 09 particularly we discovered that water 56fe values are remarkably stable 0 01 0 11 2sd n 4 before and during a strong seismic swarm period in 2000 local magnitudes ml 3 while o2 and h2 concentrations in water decrease and dissolved fe content increases later recurring events of lower 56fe values down to 0 3 are observed in the period from 2001 to 2003 with intermittent seismic events 1 ml 2 6 the observations indicate a time lag between tectonic forcing and fe isotope response the role of abiotic fluid rock interaction and fe utilizing bacteria identified in the mineral spring water on fe isotope fractionation is discussed we explain recurring changes towards isotopically lighter values by a combination of fe dissolution from deep granite and admixture of isotopically light fe generated by a complex combination of abiotic and biotic processes operating in the aquifer when disturbed by swarm earthquakes events we propose a conceptual model scenario of earthquake triggered changes in biogeochemical processes

evidence for ascending upper mantle derived melt beneath the cheb basin central europe 1 we present new 3he 4he data of co2 rich gas exhalations of three presently nonvolcanic areas in europe the 3he 4he ratios from the cheb basin czech republic are clearly higher than data obtained ten years ago whereas the 3he 4he ratios from the other areas laacher see germany and marianske lazn cr have remained nearly constant no other locality showing such high 3he 4he ratios in free gases supplied by continental mantle degassing is known in the european cenozoic rift system at the northeastern edge of the cheb basin swarm earthquakes repeatedly occur in the context of contemporaneous periods of seismicity the increased 3he 4he ratios are interpreted as the first geochemical evidence for ascending mantle derived melt beneath the cheb basin which is related to the triggering of earthquake swarms

geochemical monitoring of the 2002 2003 eruption at stromboli volcano italy precursory changes in the carbon and helium isotopic composition of fumarole gases and thermal waters significant changes in the helium and carbon isotopic composition of shallow thermal waters vs gas and a crater fumarolic gas have been recorded at stromboli prior and during the 2002 2003 eruption the3he 4he ratios corrected for air contamination rc ra and 13c of fumarolic gases gradually increased from may to november 2002 before the eruption onset these variations imply early degassing of a gas rich magma at depth that likely fed both the intense strombolian activity and small lava overflows recorded during that period the lava effusion of late december 2002 was shortly preceded by a marked rc ra decrease both in water and fumarolic gases comparison of he co2 and ch4 co2 ratios in dissolved gas and with rm delta 13 rm c rm co 2 values rules out the rc ra decrease due to an increasing input of radiogenic4he the rc ra decrease is attributed to the he isotope fractionation during rapid magma ascent and degassing a new uprising of 3he rich magma probably occurred in january to february 2003 when rc ra ratios displayed the highest values in dissolved gases ever measured before 4 56 rc ra the increase in he co2 and ch4 co2 ratios and decrease in 13c of dissolved co2 was recorded after the 5 april 2003 explosive paroxysm likely caused by enhanced gas water interaction inducing co2 dissolution no anomalous rc ra values were recorded in the same period when usual strombolian activity gradually resumed

architecture and temporal variations of a terrestrial co2 degassing site using electric resistivity tomography and self potential the hartousov mofette field in nw bohemia czech republic is characterized by strong co2 degassing from the lithospheric mantle in a test survey using electrical resistivity tomography we observed changes over time in the subsurface structure beneath heavily co2 degassing spots to depths of about 40 m and compared them to co2 gas flux and soil gas mappings from previous studies changes in the electrical resistivity were measured between september 2012 and october 2013 at irregular intervals and highlight large variations in the resistivity distribution where the co2 degassing was strongest 56 103 g m 2 day 1 indicating a fluid induced change of properties of the underlying clayey sediments positive and negative anomalies in the electric self potential parallel to the erts can be found where co2 degassing occurs which indicates varying ascent or descent of fluids within these spots some degassing spots seem not to be actively degassing continuously over time which can also be observed by other studies in the same area we suggest that future gas mappings are accompanied by methods that observe the state of fluid systems at subsurface over time e g electric resistivity tomography and self potential

active magmatic underplating in western eger rift central europe the eger rift is an active element of the european cenozoic rift system associated with intense cenozoic intraplate alkaline volcanism and system of sedimentary basins the intracontinental cheb basin at its western part displays geodynamic activity with fluid emanations persistent seismicity cenozoic volcanism and neotectonic crustal movements at the intersections of major intraplate faults in this paper we study detailed geometry of the crust mantle boundary and its possible origin in the western eger rift we review existing seismic and seismological studies provide new interpretation of the reflection profile 9hr and supplement it by new results from local seismicity we identify significant lateral variations of the high velocity lower crust and relate them to the distribution and chemical status of mantle derived fluids and to xenolith studies from corresponding depths new interpretation based on combined seismic and isotope study points to a local scale magmatic emplacement at the base of the continental crust within a new rift environment this concept of magmatic underplating is supported by detecting two types of the lower crust a high velocity lower crust with pronounced reflectivity and a high velocity reflection free lower crust the character of the underplated material enables to differentiate timing and tectonic setting of two episodes with different times of origin of underplating events the lower crust with high reflectivity evidences magmatic underplating west of the eger rift of the late variscan age the reflection free lower crust together with a strong reflector at its top at depths of 28 30 km forms a magma body indicating magmatic underplating of the late cenozoic middle and upper miocene to recent spatial and temporal relations to recent geodynamic processes suggest active magmatic underplating in the intracontinental setting

linear response of a stratified tropical atmosphere to convective forcing abstract the three dimensional response of the tropical atmosphere to an isolated heat source is investigated using a primitive equation model linearized about a resting basic state on an equatorial plane the model equations are solved by applying vertical and horizontal normal mode transforms the thermal forcing was chosen to simulate the convection which occurs over tropical south america during the southern hemisphere summer the vertical dependence of the forcing is such that the heating is zero at the top and bottom boundaries with a variable level of maximum beating the model results with steady forcing are compared with the average circulation over tropical south america for a 19 day period in the southern hemisphere summer of 1979 and it is shown that the model reproduces many aspects of the observed circulation the partition of the energy of the steady state response between the vertical modes is calculated and it is shown that the internal mode with an equivalent depth of 208 m is domina

observations of stress relaxation before earthquakes summary theory and observations suggest that seismic shear wave splitting caused by fluid saturated stress aligned microcracks directly monitors low level deformation before fracturing faulting and earthquakes occur in the past it had been assumed that the accumulation of stress before earthquakes continued until stress was released by faulting at the time of the earthquake however new data and reappraisal of existing data sets now suggests that the stress begins to relax and cracks close from tens of minutes to months before the earthquake actually occurs with the logarithm of the duration of the relaxation proportional to the magnitude of the impending earthquake the duration of the relaxation appears to be directly correlated with earthquake magnitude and may have implications for the earthquake source process and the ability to predict earthquakes

seismic imaging of the geodynamic activity at the western eger rift in central europe the western eger rift at the czech german border in central europe is an important geodynamically active area within the european cenzoic rift system ecrs in the forelands of the alps along with two other active areas of the ecrs the french massif central and the east and west eifel volcanic fields it is characterized by numerous co2 rich fluid emission points and frequent micro seismicity existence of a plume s is indicated in the upper mantle which may be responsible for these observations here we reprocess a pre existing deep seismic reflection profile 9hr and interpret the subsurface structures as mapped by seismic reflectivity with previous findings mainly from seismological and geochemical studies to investigate the geodynamic activity in the subsurface we find prominent hints of pathways which may allow magmatic fluids originating in the upper mantle to rise through the crust and cause the observed fluid emanations and earthquake activity

seismic evidence for asthenospheric updoming beneath the western bohemian massif central europe 1 detailed images of the lithosphere beneath the western bohemian massif were obtained by analysis of more than 8500 p receiver functions at the intersection of regensburg leipzig rostock zone and eger rift crustal thickness decreases to 26 km from approx 31 km in the surroundings the receiver functions display a positive phase at about 6 s delay time and a strong negative phase at 7 to 8 s which coincides with an area of moho updoming co2 mantle derived degassing and earthquake swarm activity these phases can be modeled by a velocity increase at 50 km and a velocity decrease at 65 km depth the velocity decrease observed over an area of 5300 km2 gives evidence for local asthenospheric updoming and or a confined body of partial melt which might be the cause for high co2 mantle fluid flow and earthquake swarm activity in this recently nonvolcanic intracontinental rift area

reconnaissance study of an inferred quaternary maar structure in the western part of the bohemian massif near neualbenreuth ne bavaria germany after a comprehensive geophysical prospecting the quaternary m tina maar located on a line between the two quaternary scoria cones komorni h rka kammerbuhl and elezna h rka eisenbuhl could be revealed by a scientific drilling at the german czech border in 2007 further geophysical field investigations led to the discovery of another geological structure about 2 5 km ese of the small town neualbenreuth ne bavaria germany inferred to be also a maar structure being the fourth volcanic feature aligned along the nw se trending tachov fault zone it is only faintly indicated as a partial circular rim in the digital elevation model though not expressed by a clear magnetic anomaly geoelectric and refraction seismic tomography strongly indicates a bowl shaped depression filled with low resistivity and low velocity material correlating well with the well defined negative gravity anomaly of 2 5 mgal below ca 15 m thick debris layer successions of mostly laminated sediments were recovered in a 100 m long sediment core in 2015 sections of finely laminated layers likely varves rich in organic matter and tree pollen were recognized in the upper 22 30 m and lower 70 86 m part of the core respectively interpreted as interglacials whereas mostly minerogenic laminated deposits poor in organic matter and almost barren of tree pollen are interpreted as clastic glacial deposits according to a preliminary age model based on magnetostratigraphy palynology radiocarbon dating and cyclostratigraphy the recovered sediments span the time window from about 85 ka back to about 270 ka covering marine isotope stages 5 8 sedimentation rates are in the range of 10 cm ka 1 in interglacials and up to 100 cm ka 1 in glacial phases the stratigraphic record resembles the one from m tina maar with its eruption date being derived from a nearby tephra deposit at 288 17 ka thus supporting the age model of the inferred neualbenreuth maar

transport of mantle volatiles through the crust traced by seismically released fluids a natural experiment in the earthquake swarm area vogtland nw bohemia central europe abstract vogtland which is located on the czech german border near the crossing of the eger rift and the marianske lazn fault zone is characterised by co 2 rich mineral springs fed by a magmatic source and swarm earthquake activity the free gas of the eisenquelle mineral spring was studied weekly from april 1994 to june 1996 a period which included a quake swarm on december 4 and 5 1994 comprising approximately 500 individual events m local 2 2 co seismic shifts in he content after about a month as well as in the 13 c of co 2 and 3 he 4 he after about 220 days were resolved from seasonal background variations the he concentration shift is assumed to originate near the discharge whereas the isotopic shifts are probably caused by the addition of crustal fluids released by crushing rocks within the hypocentre from the distance of 14 km between the hypocentre to the mineral spring the transport velocity of the released crustal fluids was determined to be at least 50 m day such a high speed indicates gaseous fluid transport along channel like conduits rather than being predominantly controlled by dissolution in water using a simple mass balance it is shown that the amount of crustal fluids potentially released by seismic activity strongly exceeds that required for the observed shifts in 3 he 4 he and 13 c this fact along with the coincidence of both shifts supports the hypothesis that magmatic fluids occurring in mineral waters of the eisenquelle environs flush the hypocentral crustal block by means of advectional transport

quantification of gas fluxes from the subcontinental mantle the example of laacher see a maar lake in germany abstract vertical and horizontal distributions of helium and neon isotopes were measured in the water of laacher see a maar lake in the east eifel volcanic field in germany neon is in approximate atmospheric equilibrium throughout the lake but the concentrations of both helium isotopes increase with depth and reach values of up to 10 4 he and 50 3 he times the atmospheric equilibrium concentration the isotopic ratio of the helium excess r ex 3 he ex 4 he ex is 7 42 0 03 10 6 i e r ex r a 5 36 0 02 where r a 1 384 10 6 is the isotopic ratio in air this indicates the presence of mantle derived helium laacher see is thermally stratified during the summer it acts as an almost perfect trap for injected gases the helium concentration in the hypolimnion deep water approximately doubled from may to september 1991 yielding a mean 4 he flux of 10 2 10 12 atoms m 2 s 1 this value is 30 times smaller than in lake nyos cameroon but 20 times larger than in crater lake usa release of bubbles of nearly pure co 2 99 observable in shallow waters at the eastern shore as well as detected by divers in about 30 m depth was identified as an important source of the helium excess in the lake if carefully sampled by divers to avoid air contamination the bubbles exhibit mantle influenced isotopic signatures not only for helium but also for neon and argon 20 ne 22 ne 9 92 0 03 40 ar 36 ar 391 4 based on the elemental ratios of carbon neon and argon to 3 he the fluxes of volatiles from the mantle into laacher see are determined as 7 4 10 7 atoms m 2 s 1 for 3 he 13 10 7 atoms m 2 s 1 for 20 ne 26 10 7 atoms m 2 s 1 for 361 ar and 6 4 10 17 molecules m 2 s 1 for co 2 non atmospheric neon was also found in the well wallenborn in the west eifel volcanic field with a 20 ne 22 ne ratio as high as 11 21 0 06

natural analogues a potential approach for developing reliable monitoring methods to understand subsurface co2 migration processes one possible way of mitigating carbon dioxide co2 emissions from fossil fuel combustion is using carbon dioxide capture and storage ccs technology however public perception concerning co2 storage in the geosphere is generally negative being particularly motivated by perceived leakage risks therefore a main issue when attempting to gain public acceptance is ensuring provision of appropriate monitoring practices aimed at providing health safety and environmental risk assessment so that potential risks from co2 storage are minimized naturally occurring co2 deposits provide unique natural analogues for evaluating and validating methods used for the detection and monitoring of co2 spreading and degassing into the atmosphere geological and hydrological structures of the cheb basin nw bohemia czech republic represent such a natural analogue for investigating co2 leakage and offer a perfect location at which to verify monitoring tools used for direct investigation of processes along preferential migration paths this shallow basin dating from the tertiary age is characterized by up to 300 m thick neogene sediment deposits and several tectonically active faults the objectives of this paper are to introduce the co2 analogues concept to present the eger rift as a suitable location for a natural co2 analogue site and to demonstrate to what extent such an analogue site should be used with a case study the case study presents the results obtained from a joint application of geoelectrical measurements in combination with soil co2 concentration and flux determination methods for the detection and characterization of natural co2 releases at gas seeps as part of a hierarchic monitoring concept to highlight discharge controlling structural near surface features was the initial motivation for the application of geoelectrical measurements soil gas concentration and flux measurement techniques are relatively simple to employ and are valuable methods that can be used to monitor seeping co2 along preferential pathways joint interpretation of both approaches yields a first insight into fluid paths and reveals that the thickness and permeability of site specific near surface sedimentary deposits have a great influence upon the spatial distribution of the co2 degassing pattern at surface level

a primitive equations model study of the effect of topography on the summer circulation over tropical south america abstract a nonlinear primitive equations model with five levels in a coordinate is applied to study the effects of idealized topography on the summer circulation pattern over tropical south america the model circulation is forced by prescribed latent heating centered over the amazon basin both the steady and the transient components of the response are considered and compared with the corresponding components in the absence of topography it is found that topography blocks low level inflow from the equatorial pacific and leads to the development of a steady northerly jet that is fed from the tropical atlantic other important effects of topography on the response to steady heating are found in the low level field of vertical motion the effects of topography on the response to transient heating are described in terms of a component reflected to the east and a component transmitted to the west by the topography

co2 discharge in an active non volcanic continental rift area czech republic characterisation δ13c 3he 4he and quantification of diffuse and vent co2 emissions abstract in the western eger rift er area along the pocatky plesna fault zone ppz co 2 degassing occurs predominantly within two mofette fields bublak and hartousov we studied 27 wet mofettes belonging to these mofette fields for gas emission rates repeatedly between 2007 and 2009 and selected mofettes for gas composition and isotope ratios 13 c 3 he 4 he detailed ground mapping along the ppz provided further two separated diffuse degassing structures dds within the mofette fields hartousov and bublak the dds hartousov was studied in detail by measurements of 682 co 2 soil gas concentrations 762 co 2 soil gas fluxes max 10 grid spacing and partly by analyses of isotope ratios 13 c 12 c 3 he 4 he of soil gas at the dds hartousov the total co 2 soil flux yielded 1 559 t m 2 d 1 in spring 2009 and the co 2 emission rate at the wet mofettes of hartousov mofette field yielded 0 62 t d 1 the total co 2 discharge of the 27 wet mofettes was 3 75 t d 1 at sites with high co 2 soil flux the portion of mantle derived helium is in the same range as the releasing at wet mofettes both cover the signature of the subcontinental mantle also the 13 c values analysed in the gas releasing from wet mofettes and those analysed in soil gas are nearly the same taking in account a biogenic soil co 2 flux of 25 g m 2 d 1 as background the mantle derived co 2 flux yielded approximately 1566 t m 2 d 1 as a result of the co 2 flux mapping of the dds hartousov it could be proved that 97 4 of the released soil co 2 1 518 t m 2 d 1 stems from sites with co 2 fluxes higher than 500 g m 2 d 1 pointing to dominantly fault related co 2 release at the central mofette bublak b2 the gas emission rate was determined for the first time in 1993 measurements repeated between 2007 and 2009 showed a clear increase in the gas emission rate of more than 40 correlating well with the increase of the 3 he 4 he ratios from 5 ra to approximately 6 ra between 1993 and 2008 at this location brauer et al 2009 the bublak mofette field is characterised by the highest co 2 emission rate along the ppz and in combination with the helium isotope signature of the european subcontinental mantle this area was identified as a deep reaching fluid injection zone

evidence for a nitrogen flux directly derived from the european subcontinental mantle in the western eger rift central europe in the czech german border region of the vogtland and nw bohemia western eger rift central europe chemical and isotopic compositions c n he ar of free gas from a thermal water escape fluorite mine schonbrunn two mineral springs eisenquelle bad brambach sprudel iii bad elster and a mofette bublak located along an 40 km long traverse are reported the gases of bublak and bad brambach are co2 rich 99 vol and have 13c values of 1 95 and 4 29 respectively with distance from the center of co2 degassing bublak the 13c values decrease most likely due to physico chemical fractionation of co2 between gaseous and aqueous phases rather than to admixture of organic biogenic co2 the 15n values range between 3 2 and 0 6 compared to an upper mantle value of 4 0 1 0 the four locations are characterized by 3he 4he ratios decreasing from 5 9 ra in the center bublak to 0 8 ra in the periphery schonbrunn and give evidence for mixing of he from a deep seated magmatic source with a crustal source the location with the highest 3he 4he ratio 5 9 ra is accompanied by the highest 40ar 36ar 550 we argue that the nitrogen of the bublak mofette gas is a mixture of predominantly atmospheric and mantle derived components whereas at the other three locations crustal nitrogen may also be present the bublak 15n value of 4 5 1 0 represents the first free gas 15n reference from the european subcontinental mantle escm and indicates that in contrast to the 3he 4he ratios the 15n values are equal for escm and morb respectively

relationship between amazon and high andes rainfall 1 a regional climate model is used to study the connections between amazon and high andes rainfall the modeling effort focuses on understanding the rainfall response during the last glacial maximum lgm 21 000 years ago as paleoproxy evidence generally suggests that the high andes were wet during this period while conditions over the amazon were drier although there is more uncertainty about the latter analysis of the yearlong present day and full lgm integrations reveals that the delayed onset of amazon convection in the lgm during austral spring is associated with an enhancement of rainfall over the high andes in the absence of convection over the amazon in the austral spring zonal geopotential height gradients over the amazon strengthen resulting in anomalous easterly flow between the amazon and the high andes instead of the low level flow paralleling the andes e g northwesterly the flow impinges more directly onto the eastern slopes of the andes during the lgm where it rises and transports moisture from the amazon up into the mountains enhancing convection over the andes this circulation mechanism explains how the moisture and rainfall over the high andes of peru and bolivia can increase such as the case for the lgm despite large scale drying over south america present day observations are then explored for 1984 2002 and 2003 to identify whether mechanisms identified in the paleoclimate modeling are observable in the present day climate comparison of these particular springs reveals a response analogous to the lgm model response suggesting that this mechanism that connects tropical atlantic sea surface temperatures amazon convection and high andes rainfall is operating in the present climate

temporal and spatial correlations between soil co2 flux and crustal stress in seismically active areas tectonic stress deforms and breaks the rocks of the crust ongoing deformation produces detectable modifications in the shallower portions of the crust resulting in a wide variety of changes in several parameters in this paper we report the results of a large scale spatial across an area of 15 000 km2 and temporal up to 3 years investigation of the relationship between active crustal stress and soil co2 flux we deployed a network of 10 automatic stations in most of the seismically active districts of southern italy to monitor the soil co2 fluxes and we used seismicity data to track crustal stress the results of the investigation show that the co2 flux signals varied independently in the districts with low and sporadic seismicity conversely in the only district with nearly continuous seismic activity almost all of the co2 flux signals were well correlated with each other and we recorded a clear synchronous sharp increase of the seismicity and signals recorded by several stations the high spatial and temporal correlation between seismicity and gas discharge evidenced in this study prove that the crustal stress associated with the seismogenic process is able to effectively modulate the gas release in a seismically active area

the 1994 1995 seismicity and deformation at the hengill triple junction iceland triggering of earthquakes by minor magma injection in a zone of horizontal shear stress since july 1994 an unusually persistent swarm of earthquakes m 4 0 has been in progress at the hengill triple junction sw iceland activity is clustered around the center of the hromundartindur volcanic system geodetic measurements indicate a few centimeters uplift and expansion of the area consistent with a pressure source at 6 5 3 km depth beneath the center of the volcanic system the system is within the stress field of the south iceland transform zone and the majority of the recorded earthquakes represent strike slip faulting on subvertical planes we show that the secondary effects of a pressure source modeled as a point source in an elastic half space include horizontal shear that perturbs the regional stress near the surface shear stress is enhanced in quadrants around the direction of maximum regional horizontal stress and diminished in quadrants around the direction of minimum regional stress the recorded earthquakes show spatial correlation with areas of enhanced shear the maximum amount of shear near the surface caused by the expanding pressure source exceeds 1 strain sufficient to trigger earthquakes if the crust in the area was previously close to failure

lithosphere structure of the ne bohemian massif sudetes a teleseismic receiver function study in 2004 and 2005 a passive seismic experiment was carried out in the northern and northeastern part of the bohemian massif sudetes to study the lithospheric structure we present results from ps and sp receiver function analyses with one exception moho depth at stations in the northwestern part of the study area varies between 28 and 32 km thicker crust up to 35 km was mapped toward the south moldanubian unit and toward the east moravo silesian and brunovistulian units confirming results from previous active seismic measurements there exists a relatively sharp step in moho depth between units of the central sudetes 30 km and the moravo silesian unit 35 km the vp vs ratios inverted from primary and multiple moho ps conversions hint for different crustal compositions of the units toward the carpathian thrust we have no clear indications for any crustal root or slab beneath the western carpathians however our data suggests a deepening of the moho or at least a complicated crust mantle transition in this area additional ps phases were observed between 6 and 10 s delay time in the sudetes these phases cannot be explained by moho reverberations but are most probably caused by low velocity zones in the middle crust or lithospheric mantle as shown by modeling of theoretical receiver functions the stations showing these abnormal phases are located in the area of permo carboniferous basins on probably tepla barrandian crust therefore we assume that the phases hint at a mid crustal low velocity zone between 16 and 20 km depth which is interpreted as a felsic solidified magma reservoir of the permo carboniferous volcanism beneath the sudetic basins sp receiver functions show phases with negative polarity at 9 to 12 s lead time on average which we interpret as lithosphere asthenosphere boundary at about 80 to 110 km depth

on the functioning of the southern oscillation in the south american sector part i surface climate abstract the functioning of the southern oscillation so over south america and the surrounding tropical atlantic and eastern pacific oceans is studied through analyses of bimonthly patterns of correlation between an so index and the fields of pressure wind temperature and rainfall hydrometeorological anomalies being further ascertained from river discharge and lake level records and measurements of outgoing longwave radiation most pronounced is the anomalously low pressure over the eastern pacific during the negative so phase defined by anomalously low high pressure at tahiti darwin consistently positive so pressure correlations over the eastern tropical pacific extend eastward into the north atlantic region and southern south america during the respective winter semester during the austral winter the tendency for anomalously abundant rainfall in central chile during the negative so phase appears related to an anomalously weak and northward displaced south pacific subtropical high while relativ

gas anomalies at three mineral springs and a fumarole before an inland earthquake central japan conspicuous anomalies in gas compositions were observed at a fumarole and three mineral springs about 1 3 months prior to an inland earthquake of 6 8 magnitude in central japan on september 14 1984 the epicentral distances are 9 km for the fumarole and 50 71 and 95 km for the springs the anomalies in he ar n2 ar and ch4 ar ratios of bubble gases from the springs can be attributed to fluctuations in the emission rate of some deep seated gas due to change in pore pressure which is subjected to crustal stress resulting in the earthquake the anomaly at the fumarole showed an increase in discharge rate of deep volcanic gas under a compressional stress near the focal region since the behavior of subsurface fluids represented by he ar and other ratios is presumably controlled by the change of pore pressure temporal variations in the fluids can be used as a strain gauge for the crust on the other hand the precursory emissions of h2 which were observed after changes in he ar and other ratios had occurred may have resulted from a reaction between groundwater and the surface of newly formed cracks the timing and amplitude of the geochemical anomalies are compatible with the result predicted by a dilatancy model without fluid diffusion although h2 emission may be related to groundwater permeation into newly formed cracks monitoring of several gases with automatic gas chromatographs at several stations may be useful for unraveling earthquake mechanisms and for predicting earthquakes

summertime precipitation variability over south america role of the large scale circulation abstract the observed large scale circulation mechanisms associated with summertime precipitation variability over south america are investigated particular attention is paid to the altiplano where a close relationship has been observed between rainfall and the position and intensity of the bolivian high empirical orthogonal function eof correlation and composite analyses suggest that on intraseasonal timescales typically 5 20 days rainy periods on the altiplano are associated with at least three types of circulation anomalies involving either extratropical cyclones cold core lows or the westward enhancement of the south atlantic high in each instance the primary support for high rainfall rates is a moist poleward flow at low levels along the eastern flank of the central andes in association with the south atlantic convergence zone sacz the warm low level flow along the sacz also inflates the overlying atmospheric column resulting in an intensification and southward shift of the bolivi

ammonium concentration and nitrogen isotope composition in metasedimentary rocks from different tectonometamorphic units of the european variscan belt the content and isotopic composition of ammonium nh4 were measured by using kjeldahl distillation for 63 samples of predominantly metasedimentary rocks from two different geological settings of the european variscides i e the erzgebirge and the zone of erbendorf vohenstrauss in germany the studied erzgebirge schists represent an early paleozoic passive margin sequence that reappears in different deep subducted metamorphic units this allows an efficient examination of nitrogen loss and isotope fractionation during prograde metamorphism ammonium is found to be progressively depleted accompanied by a shift in 15n from the low grade units 2 kbar 300 c with 638 124 ppm and 15n 2 2 0 6 to the garnet phyllite unit 9 kbar 470 c with 621 190 ppm and 15n 3 5 0 9 the mica schist eclogite unit 12 kbar 550 c with 394 113 ppm and 15n 3 9 0 8 and to the gneiss eclogite unit 12 kbar 730 c with 99 32 ppm and 15n 7 7 2 0 using equilibrium models for rayleigh distillation and batch volatilization suggest that the nitrogen depletion took place by ammonia release only for the mica schists this isotope fractionation can be explained by the loss of molecular nitrogen in comparison with the early paleozoic schists the proterozoic ortho and paragneisses of the erzgebirge gneiss unit 6 8 kbar 650 c contain significantly lower amounts of ammonium 70 ppm and reach relatively low 15n values 2 5 to 3 6 the paragneisses from the zone of erbendorf vohenstrauss zev sampled from the ktb pilot hole represents a separate tectonometamorphic unit that has undergone polyphase metamorphic conditions with the major imprint being amphibolite facies 7 kbar 650 700 c the metagraywackes have nh4 contents of 80 ppm and 15n of approximately 6 gneisses in the vicinity of a late cataclastic shear zone at 2000 m depth are characterized by a shift in nh4 250 ppm and 15n up to 12 which suggest late fluid rock interactions with a nitrogen and 15n enriched fluid

mantle derived volatiles in continental crust the massif central of france co2 rich gases and groundwaters from springs and boreholes originating within the basement of the massif central have variable3he 4he ratios with correspondingr ra values ranging from 0 8 to 5 5 and 0 3 to 2 8 respectively indicating the presence of a significant component of mantle helium molar concentrations of rare gases in the co2 rich gases are approximately 5 orders of magnitude greater than in the waters and suggest that a near surface henry s law fractionation has occurred between exsolving co2 and water 13c values of the co2 rich gases are in the range 4 2 to 6 1 i e in that range normally attributed to mantle carbon but which could also represent an average crustal composition and therefore do not discriminate between mantle and crustal sources c 3he ratios show 4 orders of magnitude variation from 1 4 1012 to 5 108 and compared to a mantlec 3he ratio of 109 indicate that either a complex fractionation has occurred between mantle helium and mantle co2 or more likely that mantle rare gases have been diluted by large quantities of co2 with an average crustal carbon isotope composition the regional distribution of3he and c does not show any obvious relationship to age or proximity of volcanic centres or major faults suggesting that mantle derived c and he components decoupled from their silicate melt sources at some depth the results from this area of active fluid circulation suggest that c isotope data derived from metamorphic terrains should be interpreted with great caution but that input of some mantle derived carbon is expected to accompany crustal extension

co2 rich gases from lakes nyos and monoun cameroon laacher see germany dieng indonesia and mt gambier australia variations on a common theme abstract helium r a 3 0 to 5 6 and carbon 13 c from 7 2 to 3 4 isotopic compositions and relative co 2 ch 4 n 2 he and ar contents of co 2 rich gases from lakes nyos and monoun cameroon laacher see germany dieng volcanic plateau indonesia and a well at mt gambier australia point to a common essentially magmatic origin absorption of the original magmatic gases into deeply circulating groundwater and equilibration of the resulting solutions with crustal rock at temperatures of about 300 c fix co 2 and ch 4 contents on further rise the solutions start to boil separating gas rich vapors which on encountering an impermeable barrier may accumulate to form gas pockets with steadily increasing pressures in the case of sufficiently high gas contents the pressures may exceed lithostatic pressures leading to a blow out or a pneumatic eruption dieng otherwise gas may accumulate to form a stable pocket mt gambier minor leakage from such pockets may lead to surface discharges of co 2 rich gases as at laacher see re absorption into shallow groundwater to the formation of the low salinity co 2 charged waters encountered at lakes nyos and monoun the occurrence of these high co 2 low temperature systems is likely to be favored in tectonically active regions allowing deep possibly mantle gases to rise but with sufficiently low regional heat flows to prevent the establishment of large scale geothermal activity

natural laboratory nw bohemia comprehensive fluid studies between 1992 and 2005 used to trace geodynamic processes comprehensive studies of co2 rich fluids close to the swarm earthquake region nov kostel at the czech german border have been started 15 years ago and have in particular included two extended chemical and isotope monitoring studies lasting for several years each the regional surface distribution patterns of the fluid signatures including the identification of the origin of fluid components are the focus of the detailed studies three degassing centers cheb basin marianske lazn and karlovy vary with high co2 flux and the same level of 13c values but different levels of 3he 4he ratios have been identified the studies have located the co2 source and have investigated seismically induced changes in fluid characteristics on the basis of unique weekly sampling campaigns at selected locations a seismically triggered release of crustal helium was confirmed by both monitoring campaigns finally indications for a presently active magmatic process beneath the cheb basin have been found in contrast to volcanically active regions magma accumulation in the study area takes place at the crust mantle boundary and is not yet accompanied by heat transfer to the surface likewise reactive magma derived components are absent in the degassing fluids the area of investigation has the potential to be a natural laboratory for fundamental studies of active geodynamic processes the results of our fluid monitoring including the stunning observation of mantle derived free fluids marked by 3he 4he ratios within the subcontinental mantle range are supported by geophysical findings from seismic studies and geologic indications

crustal motion in the zone of the 1960 chile earthquake detangling earthquake cycle deformation and forearc sliver translation temporary deformation in great earthquake cycles and permanent shear deformation associated with oblique plate convergence both provide critical clues for understanding geodynamics and earthquake hazard at subduction zones in the region affected by the mw 9 5 great chile earthquake of 1960 we have obtained gps observations that provide information on both types of deformation our velocity solutions for the first time span the entire latitudinal range of the 1960 earthquake the new observations revealed a pattern of opposing roughly arc normal motion of coastal and inland sites consistent with what was reported earlier for the northern part of this region this finding supports the model of prolonged postseismic deformation as a result of viscoelastic stress relaxation in the mantle the new observations also provide the first geodetic evidence for the dextral motion of an intravolcanic arc fault system and the consequent northward translation of a forearc sliver the sliver motion can be modeled using a rate of 6 5 mm a accommodating about 75 of the margin parallel component of nazca south america relative plate motion with the rate diminishing to the north furthermore the new gps observations show a southward decrease in margin normal velocities of the coastal area we prefer explaining the southward decrease in terms of changes in the width or frictional properties of the megathrust seismogenic zone because of the much younger age of the subducting plate and warmer thermal regime in the south the currently locked portion of the plate interface may be narrower using a three dimensional viscoelastic finite element model of postseismic and interseismic deformation following the 1960 earthquake we demonstrate that this explanation although not unique is consistent with the gps observations to the first order

velocity ratio variations in the source region of earthquake swarms in nw bohemia obtained from arrival time double differences crustal earthquake swarms are an expression of intensive cracking and rock damaging over periods of days weeks or month in a small source region in the crust they are caused by longer lasting stress changes in the source region often the localized stressing of the crust is associated with fluid or gas migration possibly in combination with pre existing zones of weaknesses however verifying and quantifying localized fluid movement at depth remains difficult since the area affected is small and geophysical prospecting methods often cannot reach the required resolution we apply a simple and robust method to estimate the velocity ratio between compressional p and shear s waves upsilon p upsilon s ratio in the source region of an earthquake swarm the upsilon p upsilon s ratio may be unusual small if the swarm is related to gas in a porous or fractured rock the method uses arrival time difference between p and s waves observed at surface seismic stations and the associated double differences between pairs of earthquakes an advantage is that earthquake locations are not required and the method seems lesser dependent on unknown velocity variations in the crust outside the source region it is thus suited for monitoring purposes applications comprise three natural mid crustal 8 10 km earthquake swarms between 1997 and 2008 from the nw bohemia swarm region we resolve a strong temporal decrease of upsilon p upsilon s before and during the main activity of the swarm and a recovery of upsilon p upsilon s to background levels at the end of the swarms the anomalies are interpreted in terms of the biot gassman equations assuming the presence of oversaturated fluids degassing during the beginning phase of the swarm activity

analysis of tropical extratropical interactions with influence functions of a barotropic model abstract influence functions ifs of a linear barotropic vorticity equation model are computed in order to determine the regions in which anomalous divergence at upper levels related to tropical heating anomalies has the largest impact on certain prominent low frequency anomalies the present computation differs from that of branstator in two aspects a the model includes the effects of the basic flow divergence and the advection by anomalous divergent wind and b the influence functions directly assess the influence of upper level divergence anomalies rather than sources of vorticity the ifs are applied to the study of low frequency tropical extratropical interactions at the interannual enso and intraseasonal 30 60 day oscillation timescales the origin of well known teleconnection patterns is explored through the identification of comma influence regions in the tropics and subtropics for their main action centers the subtropical west and central east pacific north of the equator is an impo

nitrogen isotope compositions of metasedimentary rocks in the catalina schist california implications for metamorphic devolatilization history abstract in the catalina schist subduction zone metamorphic complex california metasedimentary rocks show a decrease in n concentration and an increase in 15nair with increasing metamorphic grade lowest grade lawsonite albite rocks contain 632 185 ppm n with 15 n 1 9 0 6 whereas highgrade amphibolite equivalents contain 138 76 ppm n with 15 n 4 3 0 8 loss of n accompanied devolatilization reactions that evolved h2o rich c o h s n fluids through consumption of chlorite and phengitic white mica and production of mineral assemblages containing muscovite biotite garnet and kyanite whole rock n concentrations of up to 200 ppm in veins and pegmatites produced during high p t metamorphism reflect the redistribution of n during devolatilization and partial melting of the metasedimentary rocks bulk fluid rock n isotope fractionations 15n 15nfluid 15nrock of 1 5 1 were calculated with the rayleigh distillation equation taking into account variability in rock composition by comparison of samples with similar k2o concentrations these fractionations are similar to but slightly lower than published calculated fractionations for n2 nh4 exchange at the temperature range of 350 600 c over which most of the devolatilization occurred in the catalina schist approximately 3 4 to 2 25 the n systematics appear to be explained by n2 nh4 exchange and a devolatilization process intermediate in behavior to batch volatilization and rayleigh distillation the observed shifts in n concentration and 15n cannot be explained by nh3 nh4 exchange at these temperatures using the equilibrium models the distillation devolatilization process implicated in this study may govern the behavior of other trace elements partitioned into hydrous fluids during devolatilization e g b cs u similarity of the calculated fluid 15n 1 5 to 5 5 with compositions of natural gases inferred to be derived from metasedimentary sources indicates the possibility of using n as a tracer of large scale volatile transport

el nino southern oscillation enso influence on a sajama volcano glacier bolivia from 1963 to 1998 as seen from landsat data and aerial photography sajama volcano located in the bolivian altiplano is the southernmost tropical glacier and owing to its situation approximately 100 km east of the pacific coast is well suited to study the el nino southern oscillation phenomenon landsat data from 1972 to 1998 and a 1963 aerial photograph are used to monitor the snow line fluctuations on a selected part of sajama volcano we assume that a few months after the rainy season the snow line is representative of the previous rainy season if no recent snowfall has occurred by observing precipitation from the stations surrounding sajama volcano and by verifying snow presence on surrounding summits we detect images with recent snowfall likely to disturb the climatic significance of the snow line a snow line evolution model takes into account the different image acquisition dates and adjusts the snow line elevation accordingly for the middle of the dry season a progressive rise of the snow line elevation is observed from 1963 to 1998 with a sustained rise from 1984 to 1990 the snow line altitude is related to the southern oscillation index even after the high precipitation of the 1996 1997 wet season the following el nino 1997 1998 leads to a substantial rise of the snow line the snow line elevation is related primarily to the total rainy season precipitation and to a lesser degree to the maximum monthly mean temperature of the warmest month thus confirming a greater snow line sensitivity to precipitation than to temperature

the 1986 87 pacific warm episode evolution of oceanic and atmospheric anomaly fields abstract the evolution of oceanic and atmospheric anomaly fields for the period prior to and during the 1986 87 el nino southem oscillation enso is presented a comparison is made between the 1986 87 enso and other warm episodes that occurred during the last 20 yr in addition for the first time an ocean general circulation model was run in a real time diagnostic mode the model output provided detailed information about the evolution of subsurface features throughout the pacific basin a slow trend towards warm episode enso conditions in the pacific was evident throughout the period 1985 86 in certain atmospheric and oceanic variables atmospheric and oceanic fields changed much more rapidly during late 1986 as enhanced atmospheric convection developed in the equatorial pacific near the date line thermocline depths rapidly increased decreased in the eastern western equatorial pacific as low level westerlies developed in the western portion of the basin a remote response to those westerlies wa

juvenile co2in enderbites of tromoy near arendal southern norway a fluid inclusion and stable isotope study the enderbites from tromoy in the central granulite facies part of the proterozoic bamble sector of southern norway contain dominantly co2 and n2 fluid inclusions co2 from fluid inclusions in quartz segregations in enderbites was extracted by mechanical crushing and thermal decrepitation and the 13c measured measurement was also made on samples washed in 10 hcl oxidized with cuo at high temperatures and step wise extracted with progressive heating results between the different techniques are systematic the main results show 13c of 4 5 1 5 for crushing and 7 2 for thermal decrepitation 13c is about constant for co2 extracted at different temperatures and points to a homogeneous isotopic composition due to the presence of carbonate particles and or induced contaminations for the extraction by thermal decrepitation the results for the crushing experiments are assumed the most reliable for fluid inclusion co2 very low values of 13c have not been found in enderbite samples and 13c combined with 18o of the host quartzes 8 11 indicates juvenile values in addition the fluid inclusions were examined by microthermometry and raman analysis and host quartz by acoustic emission and cathodoluminescence co2 fluid inclusions have varying densities with a frequency maximum of 0 92 g cm 3 and generally do not concur with trapping densities at granulite conditions textures show that co2 must have been trapped in fluid inclusions in one early event but transformed to different extents during late isothermal uplift without important fractionation of isotope compositions the present data support a model of intrusion and crystallization of a co2 rich enderbitic magma at granuiite conditions

vegetation invasions into absolute desert a 45 th000 yr rodent midden record from the calama salar de atacama basins northern chile lat 22 24 s plant macrofossils percentage abundance of grass taxa fecal pellet d13 c and plant cuticle contents from 49 fossil rodent middens dated by 14 c record changes in local vegetation and precipitation since 45 ka calibrated or measured to thousands of calendar years before present in the central atacama desert lat 228 248s of northern chile the midden sites are along the hyperarid upper margin 2400 3100 m of the absolute desert in an extreme environment sparsely vegetated by annual herbs and halophytic shrubs conditions between 40 and 22 ka may have been at least intermittently dry and possibly cooler as implied by four middens with low species richness we infer a large increase in summer rainfall between 16 2 and 10 5 ka on the basis of the lowering of steppe grasses by as much as 1000 m prominence of c4 grasses and summer annuals high species richness and displacement of northern species at least 50 km south of their modern ranges the precipitation increase was greatest for a cluster of middens between 11 8 and 10 5 ka abrupt drying evident in a dramatic decrease in grass abundance occurred after 10 5 ka at all four midden localities increased percentages of