radon earthquake precursor studies in iceland discrete samples of geothermal water have been collected from a network of nine stations for analysis of radon 222 rn content the sampling network consisted of wells that range in wellhead temperature from 48 c to 100 c and the depths range from 38 m to 1338 m the sampling frequency at most stations was about once per week and twice per week at the station fludir the wells are either artesian or pumped more or less continuously the network covered two regions of transform faulting in iceland with seven stations in the southern iceland seismic zone sisz and two stations in northern iceland in the tjornes fracture zone tfz during 1978 and 1979 several anomalous changes in radon content were observed to precede some of the local earthquakes criteria based on tectonic regimes a magnitude distance relationship and time clustering were applied to select a set of 23 earthquakes that could be expected to be preceded by a radon anomaly the magnitude of these earthquakes ranged between 1 0 and 4 3 each of the 23 earthquakes was within the distance range of one or more stations such that altogether 57 potential observations of possible anomalies were available the method of analysis applied to the radon and earthquake data consisted of identifying radon anomalies in retrospect and resulted in nine precursory anomalies 48 cases of failure to observe an anomaly and seven false alarms the probability of observing radon anomalies before earthquakes with magnitudes between 2 0 and 4 3 the largest event observed was found to be approximately 65 based on a weekly sampling rate in the sisz five out of eight earthquakes m 2 were preceded by an anomaly in two cases anomalies were observed at two different stations prior to the same earthquake the anomalies appeared to occur farther away for larger earthquake magnitude an aquiclude that divides the sisz did not seem to affect the occurrence of radon anomalies but the amplitude of anomalies on the east side were larger than the ones on the west side the duration times of the anomalies ranged from 17 to 37 days the large number of failures to observe an anomaly indicated that the occurrence of an anomaly was more strongly dependent on local conditions and earthquake parameters than distance between epicenter and radon station some stations also appeared to be less sensitive than others and three stations never showed an anomaly during periods of bursts in local seismicity some stations reflected distinctively larger background fluctuations which hampered the correlation of the seismicity with the radon data most of the false alarms were related to disturbances caused by changes in well operation in the sisz the high rate of failure to observe an anomaly and the occurrence of false alarms was partly compensated for by operating a dense network of sampling stations wells that are utilized at moderate flow rates are less likely to show false alarms than wells utilized at high flow rates wells situated close to rock formations rich in radioactive minerals may be more likely to show anomalies than others

segmented lateral dyke growth in a rifting event at barðarbunga volcanic system iceland crust at many divergent plate boundaries forms primarily by the injection of vertical sheet like dykes some tens of kilometres long1 previous models of rifting events indicate either lateral dyke growth away from a feeding source with propagation rates decreasing as the dyke lengthens2 3 4 or magma flowing vertically into dykes from an underlying source5 6 with the role of topography on the evolution of lateral dykes not clear here we show how a recent segmented dyke intrusion in the bar arbunga volcanic system grew laterally for more than 45 kilometres at a variable rate with topography influencing the direction of propagation barriers at the ends of each segment were overcome by the build up of pressure in the dyke end then a new segment formed and dyke lengthening temporarily peaked the dyke evolution which occurred primarily over 14 days was revealed by propagating seismicity ground deformation mapped by global positioning system gps interferometric analysis of satellite radar images insar and graben formation the strike of the dyke segments varies from an initially radial direction away from the bar arbunga caldera towards alignment with that expected from regional stress at the distal end a model minimizing the combined strain and gravitational potential energy explains the propagation path dyke opening and seismicity focused at the most distal segment at any given time and were simultaneous with magma source deflation and slow collapse at the bar arbunga caldera accompanied by a series of magnitude m 5 earthquakes dyke growth was slowed down by an effusive fissure eruption near the end of the dyke lateral dyke growth with segment barrier breaking by pressure build up in the dyke distal end explains how focused upwelling of magma under central volcanoes is effectively redistributed over long distances to create new upper crust at divergent plate boundaries

compilation of non annually resolved holocene proxy climate records stacked holocene peatland palaeo water table reconstructions from northern britain abstract the number and range of holocene palaeoclimate reconstructions from various regions of the world have increased dramatically over the last decade the data density for many regions and proxies now offers the potential of robust regional scale reconstructions that avoid the problems of records from individual sites and improve communication between palaeoclimate subdisciplines and climate modellers however there are problems with chronological uncertainties and quantification of proxies which make compilation of multiple records difficult here we explore a stacking and tuning approach to the derivation of regional records from peatland climate proxies to test its applicability to non annually resolved terrestrial records twelve individual records from northern britain based on water table reconstructions from testate amoebae analysis were divided into four regions records were detrended normalised and compared within regions to identify clear correlative events the original chronologies of the records were tuned using both these events and independent age markers the stacked record for northern britain indicates pronounced changes to wet conditions at 3600 2760 and 1600 cal yr bp with more minor changes at 3060 2050 1260 860 550 and 260 cal yr bp the main wet phases are highly correlated with mid european lake highstands wider north atlantic climate change inferred from ocean and ice core records and solar variability tuning and stacking of non annual terrestrial palaeoclimate records is a new approach to the compilation and reconciliation of individual records within coherent climatic regions and provides a tool for upscaling of palaeoclimate records for climate model data comparisons

contrasting patterns of hydrological changes in europe in response to holocene climate cooling phases the quantitative reconstruction of climatic parameters from pollen and lake level data obtained at saint jorioz lake annecy eastern france gives evidence for cooler and wetter conditions during the 8 2 ka cold event a comparison of these regional data with other hydrological records reconstructed in europe for the same period suggests as a working hypothesis that mid latitudes between ca 50 and 43 underwent wetter conditions in response to the cooling whereas northern and southern europe were marked by drier climate in the latter case leading to an interruption of the sapropel 1 formation in the mediterranean a similar hydrological tri partition of europe can be observed during other holocene cooling phases associated with north atlantic ird events data indicate that the middle zone characterised by wetter climate conditions could have had a more extended latitudinal amplitude during phases of climate cooling weaker than the 8 2 ka event the differences in expansion of the wet mid european zone depending on holocene climate cooling phases could reflect variations in the strength of the atlantic westerly jet in relation with the thermal gradient between high and low latitudes

precursory and coseismic groundwater temperature perturbation an example from taiwan abstract we have conducted taiwan s first groundwater temperature earthquake precursory and coseismic signal study using totally 8 month time series of groundwater temperature from two monitoring wells in eastern taiwan we applied hilbert huang transform hht analysis to identify possible precursory signals with periods ranging from one to ten minutes and duration of tens of hours that occurred one to three days before mw 4 7 earthquakes these signals are not correlated with atmospheric and pumping processes the precursors are sensitive to an earthquake within an epicentral distance that is about 20 to 25 time of the earthquake rupture length with this limited dataset we found the rates of false positives and false negatives are 16 7 and 28 6 respectively exact physical processes that generate such signals are unclear and additional data are needed but we propose that real time groundwater temperature monitoring has potentials to become a low cost but beneficial way to complement other earthquake precursory projects for more robust short term earthquake forecasting

weathering detected by raman spectroscopy using al ordering in albite albite samples from ontario canada laboratory weathered in hcl solutions at ph 1 have been analysed and compared to unreacted mineral samples with the same crystal orientation using raman microspectrometry the study was focused on raman bands reflecting al ordering because destabilisation of al o bonds with subsequent release of al is well recognised to be a major factor in low ph dissolution of albite analyses of unweathered samples reveal that most bands in the albite spectra show variations in intensities for different crystal orientations in the wavenumber range 100 to 1200 cm 1 a well defined crystal orientation is therefore essential to a successful investigation of weathered samples unweathered albite has two bands 455 and 976 cm 1 in the spectrum normal to the 001 face which have been related to al ordering in the structure in spectra of weathered albite crystals with the same orientation the band most sensitive to alteration is 976 cm 1 this band is very strong for unreacted albite but diminishes in intensity relative to the other bands at the initial stage of weathering when dissolution continued the structural information in the range 700 to 1200 cm 1 was completely lost shown as a bandbroadening of a less organised structure while the characteristic albite bands still could be observed in the range 100 to 600 cm 1

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

a 2000 year record of solar forcing on varved lake sediment in eastern finland abstract a high resolution study was performed on varved sediments from lake lehmilampi in eastern finland varve data was collected by digital image analysis using standard 1 8 mm thick samples impregnated in epoxy and x rayed climatic variability is imprinted on varve properties varve thickness and accumulation of mineral and organic matter during the last 2000 years the cumulative counting error of the varve record is estimated as 2 3 qualitative comparison of varve parameters and residual 14c constructed from tree rings revealed close correspondence between the two records suggesting solar forcing on lake sedimentation classical climatic periods of the last millennia medieval climate anomaly 1060 1280 in the varve record and little ice age cooler phases culminating in 1340 1465 1545 1680 1850 and also in 1930 in the varve record are clearly evident in the varve record at present the physical link between solar activity levels and lake sedimentation has not been established

seismic electric signals ses and earthquakes a review of an updated van method and competing hypotheses for ses generation and earthquake triggering abstract electromagnetic phenomena are sometimes associated with seismic events but earthquake prediction using seismic electric signals ses has not been seriously considered since the early 1990s there are several causes 1 false alarms that have created panics in greece and 2 a strong critique of the varotsos alexopoulos nomicos van method used there an updated van method that includes time series analysis has made successful medium range predictions and short range predictions when coupled with seismic time series analysis four types of potential mechanisms to create precursory ses relying on deformation effects temperature effects ore mineral movement or groundwater variation are reviewed data relevant to each are insufficient to favor a single mechanism records of the number of false positive and missed events for an updated van method have not been well maintained false positives appear to be abundant and render the method unusable co seismic groundwater fluctuations are addressed and two novel hypotheses of earthquake trigger mechanism are also presented ionospherically induced electric and resultant magnetic fields to weaken rock thereby causing failure and volatiles liberated from minerals additionally promoting rock failure recommendations for further study are included

were abrupt lateglacial and early holocene climatic changes in northwest europe linked to freshwater outbursts to the north atlantic and arctic oceans during the lateglacial and early holocene abrupt millennial scale climatic variations are recorded in a wide range of high resolution proxy records from marine and terrestrial archives in nw europe our review of the evidence for these rapid climate events do not show an apparent link to possible forcing factors such as long term orbitally induced variations in solar radiation short term variations in solar activity as inferred from 14 c atmospheric carbon dioxide concentration or volcanic sulphate as recorded in the gisp2 ice core record there is however a remarkable degree of similarity with the number duration and timing of episodes of increased e ux of fresh water to the north atlantic and arctic oceans from the laurentide ice sheet and from the baltic ice lake in sw sweden these freshwater outburst events occurred when continental runoff from the laurentide ice sheet was rerouted from the mississippi river to the hudson river st lawrence river hudson strait and along the mackenzie river to the atlantic and arctic oceans and when the baltic ice lake in sw sweden drained to skagerrak periods of increased freshwater e ow to the north atlantic and arctic oceans may thus provide a mechanism to explain the abrupt and signie cant lateglacial and early holocene climate events in nw europe the idea that freshwater outbursts might drive abrupt climate events is not new but previous work may have underestimated the extent of support from proxy data and overestimated the ine uence of the laurentide ice sheet

orbital imprint on holocene palaeohydrological variations in west central europe as reflected by lake level changes at cerin jura mountains eastern france this paper presents a lake level record for the holocene at lake cerin jura mountains eastern france it is based on a range of sedimentological techniques validated in previous studies with a combination of systematic lithostratigraphic investigations of the infillings accumulated in the lacustrine basin and sediment analyses of two selected cores the chronology is based on 10 radiocarbon dates and pollen stratigraphy on a millennial scale the cerin lake level record shows three distinct successive phases characterised by higher lake level conditions until ca 9000 cal a bp followed by a maximal lowering at ca 9000 8500 cal a bp and a progressive rise until the present this rise was punctuated by centennial scale fluctuations with major events around 4000 2800 and after 1500 cal a bp considered on a multimillennial scale the general pattern of palaeohydrological changes reconstructed at cerin reflects the impact of orbitally driven summer insolation this is in agreement with other regional and extra regional palaeoclimatic records although every record shows peculiarities in timing and shape depending on the proxy used for reconstruction in this general context centennial to multicentennial oscillations appear to have been second order events in comparison with the major influence of the orbital factor copyright 2011 john wiley sons ltd

glacimarine slope sedimentation contourite drifts and bottom current pathways on the barra fan uk north atlantic margin the sedimentary record of a 30 m core md95 2006 from the barra fan in the eastern rockall trough has been correlated with high resolution seismic profiles obtained across sediment drifts and large mass flow deposits a series of sediment drifts featuring upslope migrating wavy bedforms has been identified with deposition focussed along topographic steps created by glacigenic debrite lobes the most extensive drift accumulation termed the barra fan drift is observed on the distal fringe of the fan where an 80 m thick sequence of aggrading to migrating sediment waves onlap a mega debrite scarp prior to 26 ka 14c yr and during the late glacial to holocene transition silty muddy contourites were deposited by the northward flowing deep northern boundary current between 26 and 18 ka and around 14 ka contourite deposition was replaced by distal glacimarine sedimentation featuring thin bedded sandy turbidites that were triggered during shelf edge advances of the british ice sheet during the last glacial period sediments accumulated at rates of more than 40 cm ka as a consequence of the high flux of sediments from the shelf margin and winnowing of exposed mass flow deposits by along slope currents in contrast the holocene is represented by a condensed interval of silty sandy mud due to vigorous bottom circulation and a low terrigenous sediment supply seismic seafloor signatures suggest that the present morphology of the barra fan is shaped by two pathways of bottom currents probably both related to the deep northern boundary current one branch of this water mass follows the lower slope causing pronounced erosion on the distal part of the barra fan drift while the other is directed across the debrite topography of the fan bulge

geochemical precursors to seismic activity studies of earthquake precursory phenomena during the last several decades have found that significant geophysical and geochemical changes can occur prior to intermediate and large earthquakes among the more intensely investigated geochemical phenomena have been 1 changes in the concentrations of dissolved ions and gases in groundwaters and 2 variations in the concentrations of crustal and mantle volatiles in ground gases the concentration changes have typically showed no conanomalies trend either increasing or decreasing and the spatial and temporal distribution of the observed anomalies have been highly variable as a result there is little agreement on the physical or chemical processes responsible for the observed anomalies mechanisms proposed to account for precursory groundwater anomalies include ultrasonic vibration pressure sensitive solubility pore volume collapse fracture induced increases in reactive surfaces and aquifer breaching fluid mixing precursory changes in soil gas composition have been suggested to result from pore volume collapse micro fracture induced exposure of fresh reactive silicate surfaces and breaching of buried gas rich horizons an analysis of the available field and laboratory data suggests that the aquifer breaching fluid mixing ab fm model can best account for many of the reported changes in temperature dissolved ion and dissolved gas concentrations in groundwater ultrasonic vibration and pressure sensitive solubility models cannot reasonably account for the geochemical variations observed and although the pore collapse model could explain some of the observed chemical changes in groundwater and ground gas uncertainties remain regarding its ability to generate anomalies of the magnitude observed other geochemical anomalies in particular those associated with hydrogen and radon seem best accounted for by increases in reactive surface areas irsa model that may accompany precursory deformation around the epicenter of an impending earthquake analysis of the probable response of these models to the earthquake preparation process as well as to other environmental factors suggests that geochemical monitoring programs can provide information that may be valuable in forecasting the probability of an earthquake however because of the complexity of the earthquake preparation process the absolute prediction of seismic events using geochemical methods alone does not presently appear to be feasible

solar forcing of climatic change during the mid holocene indications from raised bogs in the netherlands two cores of mid holocene raised bog deposits from the netherlands were 14 c wiggle match dated 14 c as a proxy for changes in solar activity is validated this paper adds to the increasing body of evidence that solar variability forced climatic changes during the holocene 14 c wiggle match dating mid holocene wet shifts

hydrological changes in the european midlatitudes associated with freshwater outbursts from lake agassiz during the younger dryas event and the early holocene abstract recent studies of lake level fluctuations during the last deglaciation in eastern france jura mountains and pre alps and on the swiss plateau show distinct phases of higher water level developing at the beginning and during the latter part of greenland stade 1 i e younger dryas event and punctuating the early holocene period at 11 250 11 050 10 300 10 000 9550 9150 8300 8050 and 7550 7250 cal yr b p the phases at 11 250 11 050 and 8300 8050 cal yr b p appear to be related to the cool preboreal oscillation and the 8200 yr event assumed to be associated with deglaciation events a comparison of this mid european lake level record with the outbursts from proglacial lake agassiz in north america suggests that between 13 000 and 8000 cal yr b p phases of positive water balance were the response in west central europe to climate cooling episodes which were induced by perturbation of the thermohaline circulation due to sudden freshwater releases to oceans this probably was in response to a southward migration of the atlantic westerly jet and its associated cyclonic track moreover it is hypothesized that during the early holocene varying solar activity could have been a crucial factor by amplifying or reducing the possible effects of lake agassiz outbursts on the climate

hydroquakes central apennines italy towards a hydrogeochemical monitoring network for seismic precursors and the hydro seismo sensitivity of boron abstract hydrogeochemical changes before mw 5 0 earthquakes are hoped to be applicable as seismic precursors it is now necessary to pass from single experiences to structured networks systematically monitoring large seismic areas for long periods our aim is to provide a pilot methodological experience for how such networks could be realized and the types of results they could deliver we present the method and some initial results to document the method s applicability in 2017 we started the hydroquakes project in seismically active central italy with the sulmona and matese areas selected as the two monitoring nodes each node includes 5 6 monitored springs and for each spring we performed laboratory analyses of major and trace elements and some isotopes we installed in situ probes for continuous monitoring between december 2017 and january 2020 the most energetic earthquakes were three events with mw of 3 9 4 1 and 4 4 they were not preceded by significant hydrogeochemical anomalies except for the mw 4 1 event despite its low mw this earthquake occurred over a large normal fault at a great depth in the crust 17 km and was preceded by weak but detectable hydrogeochemical anomalies of boron and 11b that were similar but milder than the hydrogeochemical anomalies before the 2016 mw 6 0 earthquake in the central apennines this and previous evidence show the b and 11b hydro seismo sensitivity and indicates that pre seismic hydrogeochemical anomalies could arise mostly before mw 5 0 earthquakes with weak exceptions occurring in specific conditions such as long and deep faults

geochemical challenge to earthquake prediction the current status of geochemical and groundwater observations for earthquake prediction in japan is described the development of the observations is discussed in relation to the progress of the earthquake prediction program in japan three major findings obtained from our recent studies are outlined i long term radon observation data over 18 years at the ske suikoen well indicate that the anomalous radon change before the 1978 izu oshima kinkai earthquake can with high probability be attributed to precursory changes ii it is proposed that certain sensitive wells exist which have the potential to detect precursory changes iii the appearance and nonappearance of coseismic radon drops at the ksm kashima well reflect changes in the regional stress state of an observation area in addition some preliminary results of chemical changes of groundwater prior to the 1995 kobe hyogo ken nanbu earthquake are presented

multicentury glacier fluctuations in the swiss alps during the holocene subfossil remains of wood and peat from six swiss glaciers found in proglacial fluvial sediments indicate that glaciers were smaller than the 1985 reference level and climatic conditions allowed vegetation growth in now glaciated basins an extended data set of swiss glacier recessions consisting of 143 radiocarbon dates is presented to improve the chronology of glacier fluctuations a comparison with other archives and dated glacier advances suggests 12 major recession periods occurring at 9850 9600 93008650 85508050 77007550 74506550 61505950 57005500 52004400 43003400 28002700 21501850 14001200 cal yr bp it is proposed that major glacier fluctuations occurred on a multicentennial scale with a changing pattern during the course of the holocene after the younger dryas glaciers receded to a smaller extent and prolonged recessions occurred repeatedly culminating around 7 cal kyr bp after a transition around 6 cal kyr bp weak fluctuations around the present level dominated after 3 6 cal kyr bp less frequent recessions interrupted the trend to advanced glaciers peaking with the prominent little ice age this trend is in line with a continuous decrease of summer insolation during the holocene

earthquake m 5 1 induced hydrogeochemical and δ18o changes validation of aquifer breaching mixing model in koyna india summary hydrochemical parameters and oxygen 18 18o were measured in groundwater from wells and spring waters from the active seismic area around koyna warna reservoirs over a period of three years 2005 2007 to explore their relationship with seismicity in comparison to average values observed later hydrochemical data of one of the wells revealed increased concentrations of chloride 100 per cent sulphate 300 per cent and fluoride 700 per cent while the 18o value decreased contemporarily to the occurrence of an earthquake of magnitude 5 1 on 2005 march 14 based on the hydrochemical and isotopic characteristics of different well waters in this area we conceptualize a model of aquifer breaching and mixing of deep aquifer water with shallow aquifer water due to the earthquake we estimated the fractions of two components of different aquifer waters mixed using two conservative tracers chloride and 18o the necessary mixing proportions of 50 per cent are unprecedented and call for further work to understand the earthquake related processes causing the observed hydrogeochemical and isotopic anomalies in the koyna warna region

chemical signature detection of groundwater and geothermal waters for evidence of crustal deformation along fault zones abstract common crustal igneous and high grade metamorphic rocks contain peroxy defects which remain dormant until the rock experiences stress upon deformation stress activated peroxy defects form highly reactive oxygen species ros at the rock water interface observed in both terrestrial and extraterrestrial rock samples the ros complex is formed upon rock fluid interaction when groundwater combines with the ros to produce hydrogen peroxide giving an indirect measure of the underlying rock stress and crustal deformation along active faults the average concentration of hydrogen peroxide from the sohna thermal spring water falling along the active sohna fault and geothermal field was measured to be 0 53 0 014 mg l similar average concentration was also recorded from borewell sample north of the spring 0 56 0 017 mg l within the same geothermal field lower concentration of hydrogen peroxide was recorded within samples collected from hard rock aquifers outside the geothermal field and the active fault zone 0 138 0 095 mg l the detailed analysis suggests that the presence of hydrogen peroxide is largely dependent on the circulation pattern through the interconnected fractures joints within the quartzite bedrock lying adjacent to the fault plane laboratory analysis results also show high hydrogen peroxide concentration within two borewell samples falling adjacent to the epicentre of a shallow microtremor event within the hard rock region falling alongside a lineament along the delhi hard rock mega fold rock water interaction post stress activation of peroxy defects and formation of ros has therefore been inferred to be responsible for the formation of hydrogen peroxide at the rock water interface within these zones this pilot study provides scientific field evidence that hydrogen peroxide concentrations within groundwaters might offer prospects for seismic stress estimation and crustal deformation along seismically active zones

the spatial and temporal complexity of the holocene thermal maximum the holocene thermal maximum a period of relatively warm climate between 11 000 and 5 000 years ago1 2 is most clearly recorded in the middle and high latitudes2 3 of the northern hemisphere where it is generally associated with the local orbitally forced summer insolation maximum however proxy based reconstructions have shown that both the timing and magnitude of the warming vary substantially between different regions2 3 4 suggesting the involvement of extra feedbacks and forcings here we simulate the holocene thermal maximum in a coupled global ocean atmosphere vegetation model we find that before 7 000 years ago summers were substantially cooler over regions directly influenced by the presence of the laurentide ice sheet whereas other regions of the northern hemisphere were dominated by orbital forcing our simulations suggest that the cool conditions arose from a combination of the inhibition of labrador sea deep convection by the flux of meltwater from the ice sheet which weakened northward heat transport by the ocean and the high surface albedo of the ice sheet we thus conclude that interglacial climate is highly sensitive to relatively small changes in ice sheet configuration

changes in solar activity and holocene climatic shifts derived from 14c wiggle match dated peat deposits closely spaced sequences of accelerator mass spectrometer ams 14 c dates of peat deposits display century scale wiggles which can be e tted to the radiocarbon calibration curve by wiggle matching such sequences high precision calendar age chronologiescan be generated which show that changes in mire surface wetness during the bronze age iron age transition c 850 cal bc and the little ice age wolf sporer maunder and dalton minima occurred during periods of suddenly increasing atmospheric concentration of 14 c replicate evidence from peat based proxy climate indicators in northwest europe suggest these changes in climate may have been driven by temporary declines of solar activity carbon accumulation rates of two raised peat bogs in the uk and denmark record low values during the little ice age which ree ects reduced primary productivity of the peat forming vegetation during these periods of climatic deterioration

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

reconstruction of hydrological changes between 7000 and 3000 bp in the upper and middle vistula river basin poland rhythmic fluctuations in the hydrological regime are demonstrated based on a review of records sensitive to relative climatic stability between 7000 and 3000 bp in the upper and middle parts of the vistula river basin central europe in the fluvial deposits and landforms these variations are very clear phases of higher flood frequency are dated 6600 6000 5500 4750 4500 4100 and 3250 3000 bp these phases coincide very well with sparse information on landslides data on high lake levels in the early subboreal phases of forest ecosystem transformation and finally the reaction of human cultures to these changes their rhythmicity correlates well with records from the alps and the alpine foreland but poorly with those from scandinavia this may be explained by changes in the zonal pattern of air mass circulation among the causes of the humid phases it is the frequency of volcanic eruptions which should be taken into consideration

continuous borehole strain and pore pressure in the near field of the 28 september 2004 m 6 0 parkfield california earthquake implications for nucleation fault response earthquake prediction and tremor near field observations of high precision borehole strain and pore pres sure show no indication of coherent accelerating strain or pore pressure during the weeks to seconds before the 28 september 2004 m 6 0 parkfield earthquake minor changes in strain rate did occur at a few sites during the last 24 hr before the earth quake but these changes are neither significant nor have the form expected for strain during slip coalescence initiating fault failure seconds before the event strain is stable at the 10 11 level final prerupture nucleation slip in the hypocentral region is constrained to have a moment less than 2 10 12 nm m 2 2 and a source size less than 30 m ground displacement data indicate similar constraints localized rupture nucleation and runaway precludes useful prediction of damaging earthquakes coseismic dynamic strains of about 10 microstrain peak to peak were superimposed on volumetric strain offsets of about 0 5 microstrain to the northwest of the epicenter and about 0 2 microstrain to the southeast of the epicenter consistent with right lateral slip observed strain and global positioning system gps offsets can be simply fit with 20 cm of slip between 4 and 10 km on a 20 km segment of the fault north of gold hill m 0 7 10 17 n m variable slip inversion models using gps data and seismic data indicate similar moments observed postseismic strain is 60 to 300 of the coseismic strain indicating incomplete release of accumulated strain no measurable change in fault zone compliance preceding or following the earthquake is indicated by stable earth tidal response no indications of strain change accompany nonvolcanic tremor events reported prior to and following the earthquake

rapid hydrological changes during the holocene revealed by stable isotope records of lacustrine carbonates from lake igelsjon southern sweden a holocene sediment sequence from lake igelsjon south central sweden was studied by stable oxygen and carbon isotope analyses of different carbonate components the deposit which covers the time span from ca 11 500 cal bp to the present was laid down in a small kettle hole lake the hydrological balance of which is presently dominated by groundwater flow isotopic records obtained on bulk carbonates originating mainly from summer produced calcitic algal encrustations exhibit several rapid shifts of more than 2parts per thousand likely reflecting pronounced hydrological variations corresponding isotopic data obtained on calcitic gastropod opercula from parts of the profile show subdued responses to major climatic shifts probably related to an extended calcification season the isotopic records were complemented by studies of modern isotope hydrology and our interpretations are based on a simplistic climate hydrology model in which variations in groundwater generation within the lake catchment produce changes in groundwater level and related adjustments of lake level and surface volume ratio of the basin during the ice free season assumed periods of decreased lake volume in a relatively dry climate low lake level are characterised by enrichment in o 18 and c 13 resulting from increased evaporation inflow ratio and atmospheric equilibration respectively in clear contrast to this situation intervals of more humid climatic conditions give rise to increased lake volume high lake level possibly surface over flow and relatively depleted isotopic ratios relatively humid conditions which may correlate to a wide spread cooling event recorded by various proxies across the north atlantic region are indicated by distinct isotopic shifts at ca 8300 and 8000 cal bp bracketing a period of o 18 depletion the period between ca 8000 and 4000 cal bp was characterised by relatively dry and stable climatic conditions whereas the subsequent part of the holocene experienced a more humid and variable climate following marked and coherent depletions in o 18 and c 13 at ca 4000 cal bp c 2002 elsevier science ltd all rights reserved less

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

high resolution analyses of an early holocene climate event may imply decreased solar forcing as an important climate trigger early holocene lacustrine tree ring ice core and marine records reveal that the northern hemisphere underwent a short cooling event at 10 300 calendar yr b p 9100 14 c yr b p the records were compared on a common high resolution time scale and show that the event lasted less than 200 yr with a cooling peak of 50 yr and the event coincides with a distinct holocene thermohaline disturbance recognized in the north atlantic ocean in spite of wellknown freshwater forcings at the time of the event the negligible difference between the modeled d 14 c record based on the gisp2 greenland ice sheet project 2 10 be data and the measured values does not allow for detectable d 14 c changes related to global ocean ventilation we can however show that the onset of the cooling coincides with the onset of one of the largest holocene 10 be flux peaks this finding may imply that the climate system is more

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

centennial scale climate cooling with a sudden cold event around 8 200 years ago the extent of climate variability during the current interglacial period the holocene is still debated temperature records derived from central greenland ice cores show one significant temperature anomaly between 8 200 and 8 100 years ago which is often attributed to a meltwater outflow into the north atlantic ocean and a slowdown of north atlantic deep water formation this anomaly provides an opportunity to study such processes with relevance to present day freshening of the north atlantic anomalies in climate proxy records from locations around the globe are often correlated with this sharp event in greenland but the anomalies in many of these records span 400 to 600 years start from about 8 600 years ago and form part of a repeating pattern within the holocene more sudden climate changes around 8 200 years ago appear superimposed on this longer term cooling the compounded nature of the signals implies that far field climate anomalies around 8 200 years ago cannot be used in a straightforward manner to assess the impact of a slowdown of north atlantic deep water formation and the geographical extent of the rapid cooling event 8 200 years ago remains to be determined

an anomalous radon decrease in groundwater prior to an m6 0 earthquake a possible precursor a significant decrease in the radon concentration of artesian groundwater was observed at a well established observation site in northeast japan about two days before an m 6 0 earthquake occurred about 200 km from the site on the basis of a concurrent in situ minus 126 m temperature drop of the groundwater the authors infer that precursory changes in regional stress were locally amplified near this site and resulted in the temporary mixing of cooler radon poor groundwater into the normal artesian flow

hydrothermal alteration of plagioclase and growth of secondary feldspar in the hengill volcanic centre sw iceland dissolution of igneous feldspar and the formation and occurrence of secondary feldspar in tholeiitic basalts from the hengill volcanic centre in sw iceland was studied by microprobe analysis of cuttings from two ca 2000 m deep geothermal wells well ng 7 in nesjavellir represents a geothermal system in a rift zone where the intensity of young insignificantly altered intrusions increases with depth well khg 1 in kolvioarholl represents the margin of a rift zone where the intensity of intrusives is lower and the intensity of alteration higher this marginal well represents altered basaltic crust in an early retrograde state the secondary plagioclase in both wells is mainly oligoclase occurring in association with k feldspar and chlorite actinolite the texture of this assemblage depends on the lithology and intensity of alteration in nesjavellir ng 7 the composition of secondary albite oligoclase is correlated with the host rock composition this connection is not apparent in more intensely altered samples from kolvioarholl khg 1 the influence of temperature on composition of secondary na feldspar is unclear in both wells although ca is expected to increase with temperature any temperature dependence may be suppressed by the influence of rock composition in nesjavellir and by retrograde conditions at kolvioarhall the absence of clear compositional gradients between igneous plagioclase and secondary feldspar and between na feldspar and k feldspar suggests that secondary feldspars formed by dissolution precipitation reactions c 2002 elsevier science b v all rights reserved less

synchronous holocene climatic oscillations recorded on the swiss plateau and at timberline in the alps eight synchronous pre roman cold phases were found at 9600 9200 8600 8150 7550 6900 6600 6200 5350 4900 4600 4400 3500 3200 and 2600 2350 radiocarbon years bp by reconstructing past climate at two sites on the swiss plateau and at timberline in the alps the cooling events during the early and mid holocene represent temperature values similar to today and apparently the onset of cooling events represents a deviation from today s mean annual temperature of about 1 c and is triggered at a 1000 year periodicity at wallisellen langachermoos 440 m a former oligotrophic lake near zurich the correlation between sum mertime lake levels and the seed production of the amphi atlantic aquatic plantnajas flexilis was used to reconstruct lake levels over a 3000 year period during the first part of the holocene at lake seedorf on the western swiss plateau 609 m the sedimentological palynological and macrofossil record revealed fluctuations of lake levels for the complete holocene from lago basso in the

coupling between mineral reactions chemical changes in groundwater and earthquakes in iceland chemical analysis of groundwater samples collected from a borehole at hafralaekur northern iceland from october 2008 to june 2015 revealed 1 a long term decrease in concentration of si and na and 2 an abrupt increase in concentration of na before each of two consecutive m 5 earthquakes which occurred in 2012 and 2013 both 76 km from hafralaekur based on a geochemical major elements and stable isotopes petrological and mineralogical study of drill cuttings taken from an adjacent borehole we are able to show that 1 the long term decrease in concentration of si and na was caused by constant volume replacement of labradorite by analcime coupled with precipitation of zeolites in vesicles and along fractures and 2 the abrupt increase of na concentration before the first earthquake records a switchover to nonstoichiometric dissolution of analcime with preferential release of na into groundwater we attribute decay of the na peaks which followed and coincided with each earthquake to uptake of na along fractured or porous boundaries between labradorite and analcime crystals possible causes of these na peaks are an increase of reactive surface area caused by fracturing or a shift from chemical equilibrium caused by mixing between groundwater components both could have been triggered by preseismic dilation which was also inferred in a previous study by skelton et al 2014 the mechanism behind preseismic dilation so far from the focus of an earthquake remains unknown

changes in groundwater chemistry before two consecutive earthquakes in iceland precursor events to earthquakes are rarely reproduced measurement of groundwater chemistry in iceland between 2008 and 2013 reveals distinct changes prior to two consecutive m5 earthquakes

quantitative reconstruction of younger dryas to mid holocene paleoclimates at le locle swiss jura using pollen and lake level data abstract pollen and lake level data from le locle in the swiss jura were used to quantitatively reconstruct climatic parameters for the younger dryas event and the first half of the holocene period the younger dryas cold event at le locle was characterized by i a general trend toward a slight increase in summer temperature and a decrease in annual precipitation and ii a marked drying phase at ca 11 900 cal yr b p that occurred between two wetter ones further phases of major deficit in moisture occured at ca 11 500 cal yr b p younger dryas holocene transition 10 800 cal yr b p 8700 cal yr b p and 6500 cal yr b p climatic parameters reconstructed here suggest that phases of higher lake level developing at ca 12 500 12 000 11 750 11 600 11 200 10 900 synchronous with the preboreal oscillation 10 400 8900 8400 8300 possibly related to the 8200 yr event and 7800 7000 cal yr b p coincided with an increase in annual precipitation a decrease in summer temperature and a shorter growing season conversely periods of low lake level corresponded to a decrease in annual precipitation an increase in summer temperature and a longer growing season this general pattern could have resulted from alternate southward northward displacements of the atlantic westerly jet

dissolution of primary minerals in natural waters abstract the saturation state of olivine plagioclase clinopyroxene orthopyroxene fe ti oxides and apatite of variable composition has been assessed in natural waters in iceland with temperature ranging from 0 c to 300 c and in situ ph from below 5 to above 10 cold waters are undersaturated with respect to olivine orthopyroxene clinopyroxene and plagioclases indicating that all these minerals tend to dissolve under weathering conditions with increasing ph and temperature the waters approach saturation with pyroxene olivine and plagioclases also the degree of undersaturation of olivine and orthopyroxene decreases with increasing fe content of the minerals and fe rich olivine and orthopyroxene are stable between 50 c and 150 c whereas mg rich ones tend to dissolve natural waters in iceland are saturated with respect to pure albite when above 50 c they are on the other hand undersaturated with ca rich plagioclase up to 250 c where the waters reach saturation pure magnetite and hematite are stable at all temperatures with increasing titanium content the minerals become unstable and the waters are undersaturated with respect to pure ulvospinel at temperatures up to 300 c pure ilmenite is however close to saturation under weathering conditions but undersaturated above 200 c f apatite is close to saturation at all temperatures on the other hand undersaturation with respect to oh apatite is observed at all temperatures the weathering susceptibilities of primary minerals of basalt in icelandic waters in increasing order are mg olivine fe olivine ti rich magnetite ca plagioclase mg orthopyroxene fe orthopyroxene clinopyroxene na plagioclase f apatite ti rich ilmenite ti poor magnetite ti poor hematite

post seismic hydrochemical changes in regional groundwater flow systems in response to the 2016 mw 7 0 kumamoto earthquake abstract an understanding of the detailed mechanisms and processes of hydrochemical changes in regional groundwater flow systems in response to large earthquakes has been hindered because of a lack of spatiotemporal datasets to describe these changes to clarify these issues we documented hydrochemical changes observed during the 2016 mw 7 0 kumamoto crustal earthquake using a large amount of analytical records for an area of ca 945 km2 from 139 wells for 82 measured parameters spatiotemporal distribution patterns of these changes were characterized based on a factor notation calculated using a 10 year data trend our results suggest that alteration of hydrogeological properties i e seismic rupturing coseismic mountain water release and release of soil pore waters caused changes in hydrochemical signatures at the regional scale most prominently reflected in elevated dissolved si diluted cl and increased co2 and organic compounds contents other hydrochemical anomalies detected at the local scale were induced by deep fluid upwelling and liquefaction this study identified the combined mechanisms and processes that generate the overall water chemistry changes in active groundwater flow systems in kumamoto our results provide new insights into coseismic hydrochemical changes that could be applied to other aquifer systems and importantly the use of groundwater resources during and after disasters