palaeotemperatures still exist in the greenland ice sheet the temperature distribution through the greenland ice sheet at the dye 3 borehole is a record of the past climatic changes in the arctic the numerical model of the temperature distribution now presented reproduces the observed temperature distribution within 0 03 k and shows that the basal ice is still cooled 5 k by the cold ice age climate the results suggest a mean ice age temperature of 32 2 c which is 12 k colder than the present temperature and a precipitation rate 50 25 of the present rate calculations of a more detailed temperature history through the present inter glacial period reveal evidence of the ad 1920 50 maximum the little ice age and the atlantic period

submarine volcanoes along the aegean volcanic arc abstract the aegean volcanic arc has been investigated along its offshore areas and several submarine volcanic outcrops have been discovered in the last 25 years of research the basic data including swath bathymetric maps air gun profiles underwater photos and samples analysis have been presented along the four main volcanic groups of the arc the description concerns i paphsanias submarine volcano in the methana group ii three volcanic domes to the east of antimilos volcano and hydrothermal activity in southeast milos in the milos group iii three volcanic domes east of christiana and a chain of about twenty volcanic domes and craters in the kolumbo zone northeast of santorini in the santorini group and iv several volcanic domes and a volcanic caldera together with very deep slopes of several volcanic islands in the nisyros group the tectonic structure of the volcanic centers is described and related to the geometry of the arc and the neotectonic graben structures that usually host them the ne sw direction is dominant in the santorini and nisyros volcanic groups located at the eastern part of the arc where strike slip is also present whereas nw se direction dominates in milos and methana at the western part where co existence of e w disrupting normal faults is observed the volcanic relief reaches 1100 1200 m in most cases this is produced from the outcrops of the volcanic centers emerging usually at 400 600 m depth and ending either below sea level or at high altitudes of 600 700 m on the islands hydrothermal activity at relatively high temperatures observed in kolumbo is remarkable whereas low temperature phenomena have been detected in the santorini caldera around kameni islands and in the area southeast of milos in methana and nisyros hydrothermal activity seems to be limited in the coastal areas without other offshore manifestations

uv induced mass independent sulfur isotope fractionation in stratospheric volcanic sulfate 1 sulfuric acid aerosols produced in the stratosphere following massive volcanic eruptions possess a mass independent sulfur isotopic signature acquired when volcanic so2 experiences uv photooxidation the volcanic data are consistent with laboratory so2 photooxidation experiments using uv light at 248 nm maximum absorption of ozone whereas sulfur isotopic anomalies previously observed in archean samples are consistent with photodissociation at 190 220 nm a mechanism of so2 photooxidation occurring in the early stage of a stratospheric volcanic plume in the range of 220 320 nm weak band absorption of so2 is also proposed since mass independent sulfur isotope anomalies in stratospheric volcanic sulfate appear to depend on the exposure of so2 to uv radiation their measurements might therefore offer the possibility to determine the degree of uv penetration in the ozone absorption window for the present and past atmospheres they can also be used to determine the stratospheric or tropospheric nature of volcanic eruptions preserved in glaciological records offering the possibility to reassess the climatic impact of past volcanic eruptions

radon measurements for earthquake prediction along the north anatolian fault zone a progress report abstract radon 222rn concentration has been continuously measured since 1983 in groundwater at a spring and in subsurface soil gas at five sites along a 200 km segment of the north anatolian fault zone near bolu turkey the groundwater radon concentration showed a significant increase before the biga earthquake of magnitude 5 7 on 5 july 1983 at an epicentral distance of 350 km and a long term increase between march 1983 and april 1985 the soil gas radon concentration showed large changes in 1985 apparently not meteorologically induced the soil gas and groundwater data at bolu did not show any obvious correlation

222ra and 226ra in geothermal waters of bayindir izmir turkey the radioactivity levels 222rn and 226ra and physico chemical properties of geothermal waters from two spas of bayindir are investigated radon and radium measurements were made with collector chamber method the radon concentrations range from 3 0 to 13 3 bq l whereas the radium varies from 0 35 to 1 71 bq l it has been observed that radon levels increase in winter and decrease in summer the 222rn 226ra ratio was found to range from 4 91 to 30 53 physico chemical properties of water samples were also analysed water samples have considerably stable total dissolved solids values slight acidity low electrical conductivity and temperature 42 48 c

single particle mineralogy of microparticles from himalayan ice cores using sem edx and atr ftir imaging techniques for identification of volcanic ash signatures abstract in this study insoluble microparticles from four discrete layers of ice cores drilled out from the east rongbuk glacier of the himalayas were characterized on a single particle basis by scanning electron microscopy coupled with energy dispersive x ray spectrometry sem edx and attenuated total reflectance fourier transform infrared atr ftir imaging the combined application of the two single particle analytical techniques for the analysis of the same individual particles provided complementary information i e their elemental compositions and morphology by sem edx and their molecular species functional groups and crystallinity by atr ftir imaging which is crucial for the definite identification of the mineral species including their polymorphs the results showed that the integrated signatures of volcanic ash va involving their mineralogical characteristics for silica polymorphs vitreous nature of silica and silicate particles chemical heterogeneity within the micrometer sized particles and unique morphology can be used to clearly differentiate micrometer sized va from the mineral dust of a soil origin on a single particle basis the different mineralogical characteristics among the volcanic samples would be due to their association with different volcanic eruptions

radon in soil gas how to identify anomalies caused by earthquakes anomalies have been observed in rn content in soil gas from 3 boreholes at the orlica fault in the krsko basin slovenia to distinguish the anomalies caused by environmental parameters air and soil temperature barometric pressure rainfall from those resulting solely from seismic activity the following approaches have been used i deviation of rn concentration from the seasonal average ii correlation between time gradients of rn concentration and barometric pressure and iii regression trees within a machine learning program approach i is much less successful in predicting anomalies caused by seismic events than approaches ii and iii if 2 criterion is used and is equally successful if 1 is used approaches ii and iii did not fail to observe an anomaly preceding an earthquake but show false seismic anomalies the number of which is much lower with iii than with ii model trees are shown to outperform other approaches a model has been built which in the seismically non active periods when rn is presumably influenced only by environmental parameters predicts the concentration with a correlation of 0 8 this correlation is reduced significantly in the seismically active periods

characteristics and possible source of a 1479 a d volcanic ash layer in a greenland ice core abstract a microparticle concentration peak in a gisp2 ice core contains volcanic glass shards of rhyolitic composition that correspond in age to the 1479 1480 a d mt st helens wn eruption these glass shards are compositionally similar to the wn tephra and constitute 83 of the total particle population the shards are very coarse grained up to 40 m diameter suggesting rapid transport from their source to greenland a major sulfate peak in the ice occurs approximately 4 months after deposition of the glass shards this difference in depositional timing suggests primarily tropospheric transport of the ash and stratospheric transport of the sulfate aerosol large scale climatic perturbations following this eruption were evidently negligible glaciochemical seasonal indicators suggest a late fall to early winter 1479 a d eruption

volcanic triggering of late pliocene glaciation evidence from the flux of volcanic glass and ice rafted debris to the north pacific ocean abstract mass accumulation rates mar of different components of north pacific deep sea sediment provide detailed information about the timing of the onset of major northern hemisphere glaciation that occurred at 2 65 ma an increase in explosive volcanism in the kamchatka kurile and aleutian arcs occurred at this same time suggesting a link between volcanism and glaciation sediments recovered by piston coring techniques during odp leg 145 provide a unique opportunity to undertake a detailed test of this possibility here we use volcanic glass as a proxy for explosive volcanism and ice rafted debris ird as a proxy for glaciation the mar of both glass and ird increase markedly at 2 65 ma further the flux of the volcanic glass increased just prior to the flux of ice rafted material suggesting that the cooling resulting from explosive volcanic eruptions may have been the ultimate trigger for the mid pliocene glacial intensification

past volcanism and climate revealed by greenland ice cores abstract a new method is outlined for estimating the annual injection of volcanic acids mainly sulphuric into the upper troposphere and the stratosphere the potentiality of the method is demonstrated by data on a number of historically well known eruptions analyses of annual layers in a mid greenland ice core reveal a continuous year by year record of the volcanic activity north of 20 s back to a d 553 comparison with various climatic records suggests that periods of frequent and violent eruptions usually coincide with cold climatic conditions for example the highest volcanic activities since a d 553 occurred in a d 1250 1500 and a d 1550 1700 i e in the initial and the culminating phases of the little ice age

poisson s ratio behaviour in various crystalline rocks application to the study of the earth s interior the study of poisson s ratio behaviour in various crystalline rocks under different temperatures and pressures shows this parameter to depend upon the rock composition rather than upon p t conditions the results of this study are presented in the form of a comparison of z distributions within the consolidated crust and continental upper mantle and the specific variations of in crust and mantle rocks underlying the voronezh crystalline massif vcm these investigations which are based upon seismic and seismological data as well as high pressure experiments should clarify in particular the composition and petrology of the earth s interior

new la icp ms cryocell and calibration technique for sub millimeter analysis of ice cores ice cores provide a robust reconstruction of past climate however development of timescales by annual layer counting essential to detailed climate reconstruction and interpretation on ice cores collected at low accumulation sites or in regions of compressed ice is problematic due to closely spaced layers ice core analysis by laser ablation inductively coupled plasma mass spectrometry la icp ms provides sub millimeter scale sampling resolution on the order of 100 m in this study and the low detection limits ng l 1 necessary to measure the chemical constituents preserved in ice cores we present a newly developed cryocell that can hold a 1m long section of ice core and an alternative strategy for calibration using ice core samples from central greenland we demonstrate the repeatability of multiple ablation passes highlight the improved sampling resolution verify the calibration technique and identify annual layers in the chemical profile in a deep section of an ice core where annual layers have not previously been identified using chemistry in addition using sections of cores from the swiss italian alps we illustrate the relationship between ca na and fe and particle concentration and conductivity and validate the la icp ms ca profile through a direct comparison with continuous flow analysis results

ground water radon anomaly before the kobe earthquake in japan radon concentration in ground water increased for several months before the 1995 southern hyogo prefecture kobe earthquake on 17 january 1995 from late october 1994 the beginning of the observation to the end of december 1994 radon concentration increased about fourfold on 8 january 9 days before the earthquake the radon concentration reached a peak of more than 10 times that at the beginning of the observation before starting to decrease these radon changes are likely to be precursory phenomena of the disastrous earthquake

volcanic ash layers from the last glacial termination in the ngrip ice core the tephrochronological record of the 1400 1640 m depth 10 000 16 000 calendar ice core years before present of the ngrip ice core has been established by particle screening of selected samples ash was identified in 20 samples correlation with ice marine and terrestrial records from volcanic source regions in the northern hemisphere positively identifies the saksunarvatn ash and the vedde ash ash zone 1 major element chemistry of the remaining identified ash layers mainly points towards an icelandic origin this tephrochronological record provides new important marker horizons for correlating the timing of the climatic changes associated with the last glacial termination within the north atlantic region as well as outlining more details concerning the frequency and composition of volcanic eruptions occurring at this deglaciation copyright 2005 john wiley sons ltd

synchronous deposition of volcanic ash and sulfate aerosols over greenland in 1783 from the laki eruption iceland 1 sulfate aerosols from the 1783 1784 a d laki eruption are widely used as a reference horizon for constraining greenland ice core time scales yet the timing of the arrival of the sulfate remains under discussion two ice cores from western greenland analyzed with high temporal resolution confirm that sulfate aerosols arrived over greenland late in 1783 concomitant with the tephra elevated concentrations of cd bi and tl all indicators of volcanic emissions and with a short lived rare earth elements anomaly thereafter sulfate deposition declined rapidly very modest concentrations of sulfate in 1784 snowfall evident in six greenland cores suggest a relatively short less than 1 year atmospheric residence time and an injection height limited to the lower stratosphere an improved estimate of the associated stratospheric sulfate burden is calculated and provides an important input for models assessing climatic impacts of this volcanic eruption

atmospheric aerosol loading and transport due to the 1783 84 laki eruption in iceland interpreted from ash particles and acidity in the gisp2 ice core abstract glass shards from the a d 1783 laki fissure eruption in iceland have been identified in the gisp2 ice core from summit greenland at a level just preceding the major acidity sulfate peak detailed reconstruction of ice stratigraphy coupled with analyses of solid particles from filtered samples indicate that a small amount of laki ash was carried via atmospheric transport to greenland in the summer of 1783 whereas the main aerosol precipitation occurred in the summer and early fall of 1784 sulfate concentrations in the ice increase slightly during late summer and fall of 1783 and remain steady throughout the winter due to slow oxidation rates during this season in the arctic the sulfate concentration rises dramatically in the spring and summer of 1784 producing a massive sulfate peak previously believed to have accumulated during the summer of 1783 and commonly used as the marker horizon in greenland ice core studies the chronology of ash and acid fallout at the gisp2 site suggests that a significant portion of the laid eruption plume penetrated the tropopause and that aerosol generated from it remained aloft for at least 1 yr after the eruption based on comparisons with other glaciochemical seasonal indicators abnormally cool conditions prevailed at summit during the summer of 1784 this further supports the claim that a significant volume of sulfate aerosol remained in the arctic middle atmosphere well after the eruption had ceased

modern seismological reassessment and tsunami simulation of historical hellenic arc earthquakes abstract neither large magnitude nor tsunamigenic earthquakes occur frequently in the eastern mediterranean hampering comprehensive study of these events and consequential hazards whenever digital data are required using analog seismograms travel time catalogs and hydrodynamic simulations we reassess here four large m 7 historical earthquakes occurring in various regions of the hellenic arc on 6 october 1947 in the peloponnesus 9 february 1948 near karpathos and a couplet east of rhodos on 24 and 25 april 1957 damaging near field tsunamis are associated with the 1947 and 1948 earthquakes results include seismic moments in units of 1027 dyn cm of 1 26 1947 0 97 1948 0 56 1957a and 1 09 1957b recovered focal mechanisms and hypocentral locations are consistent with the regional stress field resulting from the ongoing collision between the nubia plate and aegea microplate seismological reassessments indicate that the sources of the 1947 and 1948 tsunamis involved submarine slumping hydrodynamic simulations assuming a submarine landslide source for the 1948 tsunami recreate run up and inundation values consistent with eyewitness accounts presented here hydrodynamic simulations also show that the 25 april 1957 earthquake likely generated an unobserved tsunami with a maximum 50 cm run up in rhodos

geochemical constraints for the origin of thermal waters from western turkey the combined chemical composition b and sr isotopes and the basic geologic setting of geothermal systems from the menderes massif in western turkey have been investigated to evaluate the origin of the dissolved constituents and mechanisms of water rock interaction four types of thermal water are present 1 a na cl of marine origin 2 a na hco3 type with high co2 content that is associated with metamorphic rocks of the menderes massif 3 a na so4 type that is also associated with metamorphic rocks of the menderes massif with h2s addition and 4 a ca mg hco3 so4 type that results from interactions with carbonate rocks at shallow depths the na cl waters are further subdivided based on br cl ratios water from the cumali seferihisar and bodrum karaada systems are deep circulated seawater br cl sea water whereas water from canakkale tuzla br cl sea water are from dissolution of messinian evaporites good correlations between different dissolved salts and temperature indicate that the chemical composition of the thermal waters from non marine geothermal systems is controlled by 1 temperature dependent water rock interactions 2 intensification of reactions due to high dissolved co2 and possibly hcl gasses and 3 mixing with overlying cold groundwater all of the thermal water is enriched in b the b isotopic composition 11b 2 3 to 18 7 n 6 can indicate either leaching of b from the rocks or b oh 3 degassing flux from deep sources the large ranges in b concentrations in different rock types as well as in thermal waters from different systems suggest the water rock mechanism 87sr 86sr ratios of the thermal water are used to differentiate between solutes that have interacted with metamorphic rocks 87sr 86sr ratio as high as 0 719479 and carbonate rocks low 87sr 86sr ratio of 0 707864

long range transport of volcanic ash to the greenland ice sheet betzer et al 1 reported the surprising discovery of giant 75 m mineral particles transported more than 10 000 km from their source we have found volcanic ash containing glass shards as large as 300 m in a section of wisconsinian ice from the dye 3 core in greenland which is similarly unexpected and raises interesting questions concerning the long range aeolian transport of particulate matter as the volcanic ash correlates well with similar ash in deep sea sediment cores from the atlantic it also allows us to date the ice with some confidence

spatial radon anomalies on active faults in california abstract radon emanation has been observed to be anomalously high along active faults in many parts of the world we tested this relationship by conducting and repeating soil air radon surveys with a portable radon meter across several faults in california the results confirm the existence of fault associated radon anomalies which show characteristic features that may be related to fault structures but vary in time due to other environmental changes such as rainfall across two creeping faults in san juan bautista and hollister the radon anomalies showed prominent double peaks straddling the fault gouge zone during dry summers but the peak to background ratios diminished after significant rain fall during winter across a locked segment of the san andreas fault near olema the anomaly has a single peak located several meters southwest of the slip zone associated with the 1906 san francisco earthquake across two fault segments that ruptured during the magnitude 7 5 landers earthquake in 1992 anomalously high radon concentration was found in the fractures three weeks after the earthquake we attribute the fault related anomalies to a slow vertical gas flow in or near the fault zones radon generated locally in subsurface soil has a concentration profile that increases three orders of magnitude from the surface to a depth of several meters thus an upward flow that brings up deeper and radon richer soil air to the detection level can cause a significantly higher concentration reading this explanation is consistent with concentrations of carbon dioxide and oxygen measured in soil air samples collected during one of the surveys

seismic refraction studies of the afro arabian rift system a brief review abstract the crustal and uppermost mantle structure of major units of the afro arabian rift system has been consecutively investigated by seismic refraction surveys in the jordan dead sea rift the red sea the afar depression and the east african rift of kenya with the exception of the jordan dead sea transform the entire afro arabian rift system is underlain by anomalous mantle with pn velocities less than 8 km s while under the rift flanks the velocity is clearly equal to or above 8 0 km s various styles of rifting have been found oceanic crust floors the axial trough of the southern red sea rift thinned continental crust underlies the margins of the red sea as the afar depression and the northern kenya rift on the other hand 30 35 km thick continental crust is found both under the jordan dead sea rift where strike slip rifting is active and thinning towards the mediterranean occurs and under the central kenya rift where updoming is apparently the controlling feature while the transition from thinned continental to 5 6 km thick oceanic crust in the centre of the red sea appears to be more gradual the transition from rift related structure to undisturbed continental crust of 40 5 km thickness is mostly rather abrupt the seismic data indicate various stages of rifting evidenced by different styles of crustal strucre and they imply the presence of heated uppermost mantle under most parts of the rift system possibly related to plume activity local volcanism may disrupt and or underplate the crust in places altering in particular the structure of the lower crust progressive thickening of the rifted crust away from the oceanized centres in the southern red sea and gulf of aden towards north and south may be viewed as an evolutionary sequence which however may be difficult to explain when viewing the afro arabian rift system as an active rift controlled by plume activity

volcanic and deformation history of the bodrum resurgent caldera system southwestern turkey abstract the volcanic rocks of the bodrum peninsula in sw turkey and ne of the hellenic arc outcrop over an area of 138 km 2 a monzonitic intrusion is exposed in the western part of the peninsula upper miocene volcanism is represented by high k hk andesitic andesitic lava flows and pillows sparse hk andesitic and dacitic lava domes and associated block and ash flows a hk andesitic ignimbrite sequence with two stratigraphic units is associated with the collapse of a complex caldera system breccias formed as a result of slumping of the caldera walls are observed inside the caldera post caldera activity is represented by hk andesitic hk basaltic andesitic lava flows domes and associated block and ash flows numerous dykes hk andesitic and shoshonitic in composition cut all volcanic units the structure of the bodrum caldera was investigated using spot image digital elevation model dem aerial photographs as well as field data the bodrum caldera is a ne sw elongated semi elliptical deeply eroded caldera with dimensions of 18 7 7 7 km it is partly submerged in the sw part the complex caldera system can be described in terms of two structural domains the collapse of the dagbelen domain is interpreted as a piston type subsidence while the karakaya domain represents a piecemeal collapse both domains exhibit two separate resurgence events the elongation of the caldera may be related to pre existing regional tectonic structures the caldera is also affected and cut by late stage faults related to regional extensional events moreover pre caldera volcanism is dispersed and cannot be related to a pre existing stratovolcano bodrum volcanism is therefore interpreted as a complex ignimbritic shield volcano