climatic impact of the millennium eruption of changbaishan volcano in china new insights from high precision radiocarbon wiggle match dating climatic impact here we report a new high precision 14 c wiggle match age of a d 9463 obtained from a 264year old tree trunk with bark killed during the eruption using the oxcal s bayesian modeling approach with 27 sequentially sampled annual rings of decadal intervals the new chronology conforms well to the calendar date of a d 946 for the eruption inferred from historical documentary evidence we find no stratospherically loaded sulfate spike that might be associated with the a d 946 eruption in the global volcanism record from the gisp2 ice core suggesting the stratospheric sulfate aerosols produced during the eruption were not transported to the arctic region due probably to its relatively low stratospheric sulfur emission and the seasonal effects of the atmospheric circulation at the time of the eruption that likely occurred in the winter of a d 946 947 since the stratospheric volcanic sulfates are the main cause of large scale climate perturbations this finding indicates that the millennium eruption of changbaishan volcano might have limited regional climatic effects rather than global or hemispheric impact as implied by its magnitude citation xu j b pan t liu i hajdas b zhao h yu r liu and p zhao 2013 climatic impact of the millennium eruption of changbaishan volcano in china new insights from high precision radiocarbon wiggle match dating geophys res lett 40 doi 10 1029 2012gl054246

mineralogical hydrogeochemical and isotopic characteristics of the žveplenica sulphide karstic spring trebusa valley nw slovenia sulphide springs in slovenia are very rare and they form a peculiar feature in a carbonate setting the basic geological hydrogeochemical and isotopic characteristics of the veplenica sulphide dolomite spring trebusa valley nw slovenia were investigated along with the geochemical and mineralogical characteristics of the sediment deposited at the spring location geological mapping defined a small structurally and lithologically isolated dolomitic aquifer the major groundwater geochemical composition is hco3 mg2 ca2 indicating dissolution of dolomite the concentration of so42 was very low the groundwater was generally close to saturation with respect to calcite and dolomite geochemical modelling and other analyses indicated sulphur to originate not from gypsum and or anhydrite but from some other sources we suggest the origin of sulphur be the dissolution of volcanogenic sulphidic enrichment in a highly variable ladinian clastic limestone volcanic rock association forming the basis of early carnian cordevolian dolomite from which the spring discharges the measured 13cdic value of 11 9 indicates groundwater with a contribution of degraded organic matter and dissolved inorganic carbon in the aquifer the isotopic composition of oxygen 18oh2o hydrogen dh2o and tritium was 8 1 d 51 4 and 3h 3 64 tu respectively the 18o and d values indicated recharge from precipitation with h2s exsolution while the 3h activity shows groundwater older than 40 years mineralogical and geochemical analysis of sediment showed a typical carbonate mostly dolomite composition which was in agreement with the geochemical and isotopic composition of the groundwater of the spring indicating a deep sourced inorganic form of sulphur such as pyrite

tsunami generation of the 1993 hokkaido nansei oki earthquake heterogeneous fault motion of the 1993 hokkaido nansei oki earthquake is studied by using seismic geodetic and tsunami data and the tsunami generation from the fault model is examined seismological analyses indicate that the focal mechanism of the first 10 s when about a third of the total moment was released is different from the overall focal mechanism a joint inversion of geodetic data on okushiri island and the tide gauge records in japan and korea indicates that the largest slip about 6 m occurred in a small area just south of the epicenter this corresponds to the initial rupture on a fault plane dipping shallowly to the west the slip on the northernmost subfault which is dipping to the east is about 2 m while the slips on the southern subfaults which are steeply dipping to the west are more than 3 m tsunami heights around okushiri island are calculated from the heterogeneous fault model using different grid sizes computation on the smaller grids produces larger tsunami heights that are closer to the observed tsunami runup heights tsunami propagation in the nearly closed japan sea is examined as the free oscillation of the japan sea the excitation of the free oscillation by this earthquake is smaller than that by the 1964 niigata or 1983 japan sea earthquake

total analysis of the 1993 hokkaido nansei oki earthquake using seismic wave tsunami and geodetic data the fault geometry and slip distribution of the hokkaido nansei oki japan earthquake of july 12 1993 are estimated using seismic wave tsunami and geodetic data the moment tensor rate function inversion from p waves shows one nodal plane shallowly dipping to the west and the other nodal plane steeply dipping to the east the best depth is estimated as 10 15 km the source time history consists of an initial pulse with a duration of 10 s and moment release of 2 1020 nm followed by a complex rupture for at least 40 s the centroid moment tensor cmt solution shows one nodal plane shallowly dipping to the east and the other steeply dipping to the west the overall seismic moment is estimated as 5 5 1020 nm mw 7 8 the joint inversion of geodetic data on okushiri island and tsunami waveforms in japan and korea shows that the largest slip about 6 m occurred at a small area just south of the epicenter this corresponds to the initial rupture on a fault plane dipping shallowly to the west the slip on the northernmost fault dipping to the east is about 2 m the slips on the southern faults dipping steeply to the west are more than 3 m total seismic moment of 4 9 1020 nm estimated from the slip distribution is similar to the estimate from cmt inversion

multi proxy dating the millennium eruption of changbaishan to late 946 ce ranking among the largest volcanic eruptions of the common era ce the millennium eruption of changbaishan produced a widely dispersed tephra layer known as the b tm ash which represents an important tie point for palaeoenvironmental studies in east asia hitherto there has been no consensus on its age with estimates spanning at least the tenth century ce here we identify the cosmogenic radiocarbon signal of 775 ce in a subfossil larch engulfed and killed by pyroclastic currents emplaced during the initial rhyolitic phase of the explosive eruption combined with glaciochemical evidence from greenland this enables us to date the eruption to late 946 ce this secure date rules out the possibility that the millennium eruption contributed to the collapse of the bohai kingdom manchuria korea in 926 ce as has previously been hypothesised further despite the magnitude of the eruption we do not see a consequent cooling signal in tree ring based reconstructions of northern hemisphere summer temperatures a tightly constrained date for the millennium eruption improves the prospect for further investigations of historical sources that may shed light on the eruption s impacts and enhances the value of the b tm ash as a chronostratigraphic marker

diatom biostratigraphy of tsunami deposits examples from the 1998 papua new guinea tsunami abstract distinctive diatom assemblages may be associated with tsunami sediments and may often contrast with the assemblages found within sediments underlying the tsunami deposit as well as those associated with the modern coastal environment sediments associated with the 1998 tsunami that destroyed much of the sissano lagoon area in northern papua new guinea have been investigated surface sediments from three transects across the sediment spit near warapu have been examined for diatom content and preservation the preservation is variable and the data show an often chaotic assemblage that can be attributed to the tsunami waves incorporating and depositing diatoms from distinctive habitat zones during their runup and subsequent backwash the diatoms identified within the warapu sediments indicate an origin from within the inter tidal and offshore area rather than from the beach sand spit complex the sand deposits disclose a high percentage in excess of 75 of broken diatom valves and a predominance of centric circular species due to preferential preservation the study demonstrates that the application of diatom biostratigraphy to modern tsunami deposits can be used in conjunction with other stratigraphical lines of evidence to interpret the source and provenance of historical and palaeo tsunami deposits

tsunami deposits from the 1993 southwest hokkaido earthquake and the 1640 hokkaido komagatake eruption northern japan the southwest hokkaido tsunami of july 12th 1993 left continuous onshore sand deposits along the west coast of oshima peninsuka hokkaido northern japan we investigated spatial distribution and lithofacies of the new tsunami deposits for its identification of ancient tsunami deposits an eyewitness acount and bent plants helped our interpretation of the onshore tsunami behavior we regard the following properties as typical of the coastal tsunami sand deposits 1 the deposits cover the surface almost continuously on gentle topography 2 deposit thicknesses and mean grain sizes descrease with distance from the sea 3 deposit thicknesses and lithofacies vary greatly across local surface undulation 4 graded bedding reflecting tsunami runup and backwash is present in thick deposits 5 the deposits are widely distributed along the coast and extend inland several tens of meters to 100 m we examined a candidate for the paleo tsunami deposits associated with the 1640 komagatake eruption and confirmed that the similar patterns are typical of ancient tsunami deposits

coastal sedimentation associated with the tohoku tsunami of 11 march 2011 in south kuril islands nw pacific ocean sediment deposited by the tohoku tsunami of march 11 2011 in the southern kurils kunashir shikotan zeleniy yuri tanfiliev islands was radically different from sedimentation during local strong storms and from tsunamis with larger runup at the same location sediments from the 2011 tohoku tsunami were surveyed in the field immediately and 6 months after the event and analyzed in the laboratory for sediment granulometry benthos foraminifa assemblages and diatom algae run up elevation and inundation distance were calculated from the wrackline accumulations of driftwood woody debris grass and seaweed marking the distal edge of tsunami inundation run up of the tsunami was 5 m at maximum and 3 4 m on average maximum distance of inundation was recorded in river mouths up to 630 m but was generally in the range of 50 80 m although similar to the local strong storms in runup height the tsunami generally did not erode the coast nor leave a deposit however deposits uncharacteristic of tsunami described as brown aleuropelitic silty and clayey mud rich in organic matter were found in closed bays facing the south kuril strait these closed bays were covered with sea ice at the time of tsunami as the tsunami waves broke the ice the ice floes enhanced the bottom erosion on shoals and destruction of low lying coastal peatland even at modest ranges of runup in the muddy tsunami deposits silt comprised up to 64 and clay up to 41 5 the foraminifera assemblages displayed features characteristic of benthic microfauna in the near shore zone deep sea diatoms recovered from tsunami deposits in two closely situated bays namely krabovaya and otradnaya bays had different requirements for environmental temperature suggesting these different diatoms were brought to the bays by the tsunami wave entraining various water masses when skirting the island from the north and from the south

characteristics of the 2011 great tohoku tsunami on the russian far east coast deep water and coastal observations the source region of the catastrophic tohoku tsunami of 11 march 2011 was not far from the russian far east coast the sakhalin tsunami warning center at yuzhno sakhalinsk issued an alert for threatened coasts of the kuril islands and kamchatka the observed tsunami heights were up to 2 2 5 m along the pacific coast of the kuril islands the tsunami was clearly recorded by a number of coastal tide gauges and by deep ocean bottom pressure stations located in the vicinity of the kuril islands as well as by the russian open ocean dart station 21401 located eastward from the south kuril islands the data from other dart stations in particular those located near japan and the aleutian islands were used for comparison the records from these instruments were used to estimate the major characteristics of the tsunami waves including arrival times maximum heights durations of the signal and main wavelength periods as well as for comparison with the results of numerical modelling in contrast to deep sea stations where the first waves were the highest at russian coastal sites the highest waves occurred several hours after the arrival of the first tsunami wave further analysis indicated significant differences in spectral characteristics of tsunami waves propagating eastward toward north america and those directed in the northeast direction towards the russian far east the main peaks of the eastward propagating tsunami waves were relatively high frequency periods ranging from 6 8 to 15 20 min while those propagating in the northeast direction were mainly low frequency ranging from 25 40 to 60 80 min additionally pronounced spectral peaks with similar long periods were found in the middle field records at hanasaki on the northeastern coast of hokkaido island at yuzhno kurilsk kunashir island and at malokurilsk shikotan island at remote stations the resonant periods associated with local topographic features were predominant in the spectra

incipient subduction and deduction along the eastern margin of the japan sea the eastern margin of the japan sea has been under convergent tectonics since sometime after the pliocene the suture line is on the ocean continent boundary between the japan yamato basins and the tohoku northeast japan arc incipient subduction and obduction of the oceanic and sub oceanic crust are observed along the suture line with the occurrence of numerous n s trending fault bounded ridges and troughs focal mechanism solutions of several compressional type earthquakes with magnitudes of m 6 9 to 7 7 which have occurred along the zone are consistent with the observation of geological thrust faults the convergent stresses in the japan sea may be due to india eurasia collision and its associated intra plate or inter microplate movements in east asia the eastward movement of the amurian plate causes baikal extension along its western margin and the japan sea convergence along its eastern margin

manifestation of the 2011 great tohoku tsunami on the coast of the kuril islands a tsunami with ice the tsunami generated by the 2011 tohoku earthquake mw 9 0 reached maximum heights of about 5 m along the coast of the kuril islands the most essential feature of this event was sea ice about 0 5 m thick moved by the ocean water the tsunami did not cause any essential damage on the kuril islands but significantly affected coastal zones and produced interesting effects the problem of a tsunami accompanied by marine ice is discussed and illustrated with photos

present tectonics of the southeast of russia as seen from gps observations summary the present tectonics of northeast asia has been extensively investigated during the last 12 yr by using gps techniques nevertheless crustal velocity field of the southeast of russia near the northeastern boundaries of the hypothesized amurian microplate has not been defined yet the gps data collected between 1997 february and 2009 april at sites of the regional geodynamic network were used to estimate the recent geodynamic activity of this area the calculated gps velocities indicate almost internal between network sites and external with respect to the eurasian tectonic plate stability of the investigated region we have not found clear evidences of any notable present day tectonic activity of the central sikhote alin fault as a whole this fault is the main tectonic unit that determines the geological structure of the investigated region the obtained results speak in favour of the existence of a few separate blocks and a more sophisticated structure of the proposed amurian microplate in comparison with an indivisible plate approach

diatom assemblages in tsunami deposits associated with the 2004 indian ocean tsunami at phra thong island thailand abstract diatom assemblages in sandy deposits of the 2004 tsunami at phra thong island thailand may provide clues to flow conditions during the tsunami the tsunami deposits contain one or more beds that fine upward commonly from medium sand to silty very fine sand diatom assemblages of the lowermost portion of the deposit predominantly comprise unbroken beach and subtidal species that live attached to sand grains the dominant taxa shift to marine plankton species in the middle of the bed and to a mix of freshwater brackish and marine species near the top these trends are consistent with expected changes in current velocities of tsunami through time during high current velocities medium sand is deposited only beach and subtidal benthic diatoms attached to sediment can be incorporated into the tsunami deposit high shear velocity keeps finer material including planktonic diatoms in suspension with decreasing current velocities finer material including marine plankton can be deposited finally during the lull between tsunami waves the entrained freshwater brackish and marine species settle out with mud and plant trash low numbers of broken diatoms in the lower medium sand implies rapid entrainment and deposition whilst selective breakage of marine plankton thalassionema nitzschioides and thalassiosira and coscinodiscus spp in the middle portion of the deposit probably results from abrasion in the turbulent current before deposition

can the okhotsk plate be discriminated from the north american plate the plate geometry in northeast asia has been a long standing question with a major issue being whether the sea of okhotsk and northern japanese islands are better regarded as part of the north american plate or as a separate okhotsk plate this question has been difficult to resolve because earthquake slip vectors along the kuril and japan trenches are consistent with either pacific north america or pacific okhotsk plate motion to circumvent this difficulty we also use slip vectors of earthquakes along sakhalin island and the eastern margin of the japan sea and compare them to the predicted eurasia okhotsk and eurasia north america motions for a model with a separate okhotsk plate we invert 10 eurasia okhotsk and 255 pacific okhotsk slip vectors with pacific north america and eurasia north america nuvel 1 data alternatively for a model without an okhotsk plate those eurasia okhotsk and pacific okhotsk data are regarded as eurasia north america and pacific north america data respectively the model with an okhotsk plate fits the data better than one in which this region is treated as part of the north american plate because the improved fit exceeds that expected purely from the additional plate the data indicate that the okhotsk plate can be resolved from the north american plate the motions on the okhotsk plate s boundaries predicted by the best fitting euler vectors are generally consistent with the recent tectonics the eurasia okhotsk pole is located at northernmost sakhalin island and predicts right lateral strike slip motion on the nne striking fault plane of the may 27 1995 neftegorsk earthquake consistent with the centroid moment tensor focal mechanism and the surface faulting along the northern boundary of the okhotsk plate the north america okhotsk euler vector predicts left lateral strike slip consistent with the observed focal mechanisms on the nw boundary of the okhotsk plate the eurasia okhotsk euler vector predicts e w extension discordant with the limited focal mechanisms and geological data this misfit may imply that another plate is necessary west of the magadan region in southeast siberia but this possibility is hard to confirm without further data such as might be obtained from space based geodesy

tsunamis caused by offshore active faults and their deposits abstract this paper reviews the variable features of coastal tsunamis caused by offshore active faults along the eastern margin of the japan sea emjs based on the historical records and modern observations of earthquakes and tsunamis tsunami deposits discovered along the emjs coast were also introduced and categorized depending on their sedimentary environments the offshore active faults which are densely distributed along the emjs and generate tsunamis are originated from the opening of the japan sea back arc basin during the late oligocene to miocene period the magnitudes of the earthquakes that caused large tsunamis in the emjs were under 8 0 the size of the fault plane approximately equal to the tsunami source area was approximately 10 100 and several tens of kilometers in length the slip distance of the reverse type faults was less than 20 m the sedimentary characteristics and depositional processes of tsunami deposits were obtained from deposits in various environments such as coastal lowlands marine terraces coastal lagoons and inland ponds certain unique approaches used to identify tsunami deposits were reviewed such as gravel layers that intercalate inorganic soils and a holocene marine terrace dinoflagellate cysts and foraminiferal linings which are potentially derived from the sea and chemical features e g the ca2 mg2 ratio as indicators of seawater inflow into a coastal lagoon the spatial distribution and recurrence of earthquakes and tsunamis in the emjs were found based on previous paleo tsunami studies the difference between tsunami deposits caused by offshore active faults and those by megathrust earthquakes only manifests itself in the horizontal and vertical directions but not in the sedimentary environments and structures the data thus inferred can be used for the estimation of offshore active fault models and validation of previous tsunami disaster reconstructions in the future

the curvature of wadati benioff zones and the torsional rigidity of subducting plates it is an axiom of plate tectonics that lithospheric plates are to a good approximation torsionally rigid that is inextensible in the plane of the plate1 3 although few scientists would question this assumption when it is applied to oceanic lithosphere at the earth s surface there is no consensus as to whether or not oceanic lithosphere maintains its mechanical integrity during subduction com pare refs 4 7 with refs 8 11 i show here that the shapes of many wadati bemoff zones are inconsistent with the notion that they manifest subducted portions of oceanic plates subject only to very small 1 membrane strains

hydrogeochemistry of alpine springs from north slovenia insights from stable isotopes abstract spring water chemistry and carbon cycling in our study mainly depend on geological composition of the aquifer the investigated alpine springs in slovenia represent waters strongly influenced by chemical weathering of mesozoic limestone and dolomite only one spring was located in permo carboniferous shales the carbon isotopic composition of dissolved inorganic carbon dic and suspended organic carbon poc as well as major solute concentrations yielded insights into the origin of carbon in alpine spring waters the major solute composition was dominated by carbonic acid dissolution of calcite waters were generally close to saturation with respect to calcite and dissolved co 2 was up to fortyfold supersaturated relative to the atmosphere 13 c of dic indicates the portion of soil co 2 contributed in water and is related with soil thickness of infiltrating water in aquifer and could be therefore used as a tool for vulnerability assessment the 13 c of dic ranged from 15 8 to 1 5 and indicated less and more vulnerable aquifers mass balances of carbon for spring waters draining carbonate rocks suggest that carbonate dissolution contributes from approximately 49 to 86 and degradation of organic matter from 13 7 to 51 4 depending on spring and its relation with rock type soil environment and geomorphic position stable oxygen isotope composition of water 18 o h2o and tritium values range from 12 2 to 9 3 and from 6 4 to 9 8 tu respectively and indicate recharge from modern precipitation according to active decay of tritium and tritium in modern precipitation the age of spring waters are estimated to be about 2 6 years for springs located in julian alps about 5 years for springs located in karavanke and about 5 years for springs located in kamnisko savinjske alps

re examination of the 1940 shakotan oki earthquake and the fault parameters of the earthquakes along the eastern margin of the japan sea abstract the fault model of the 1940 shakotan oki japan earthquake of aug 1 1940 is re examined on the basis of magnitude aftershock distribution and tsunami data from a careful examination of the s p time distribution of aftershocks and comparison of the tide gauge records with numerical simulation of tsunami the fault area is estimated to be 100 km 35 km the slip 1 5 m and the seismic moment 2 4 1027 dyn cm the fault parameters estimated in this study are significantly different from those of fukao and furumoto and do not support their conclusion that this event has a very long duration and is a tsunami earthquake the source process time is estimated to be 30 s which is normal for an earthquake of this size fault parameters of six earthquakes along the eastern margin of the japan sea including the shakotan oki event are compiled and compared with those of inter plate earthquakes in the pacific ocean different relations from well known scaling laws of the inter plate shocks are found for the earthquakes in the japan sea dip angles aspect ratios of the fault and the average stress drop are larger in the japan sea than those of the pacific events although the seismic moment release per unit fault length is the same the differences can be interpreted in terms of a recent plate boundary model in which the young immature boundary between the north american and the eurasian plates lies at the eastern margin of the japan sea they also partially reflect the different excitation of the tsunami in the japan sea and the pacific ocean

three dimensional geological modelling and multivariate statistical analysis of water chemistry data to analyse and visualise aquifer structure and groundwater composition in the wairau plain marlborough district new zealand summary concerns regarding groundwater contamination with nitrate and the long term sustainability of groundwater resources have prompted the development of a multi layered three dimensional 3d geological model to characterise the aquifer geometry of the wairau plain marlborough district new zealand the 3d geological model which consists of eight litho stratigraphic units has been subsequently used to synthesise hydrogeological and hydrogeochemical data for different aquifers in an approach that aims to demonstrate how integration of water chemistry data within the physical framework of a 3d geological model can help to better understand and conceptualise groundwater systems in complex geological settings multivariate statistical techniques e g principal component analysis and hierarchical cluster analysis were applied to groundwater chemistry data to identify hydrochemical facies which are characteristic of distinct evolutionary pathways and a common hydrologic history of groundwaters principal component analysis on hydrochemical data demonstrated that natural water rock interactions redox potential and human agricultural impact are the key controls of groundwater quality in the wairau plain hierarchical cluster analysis revealed distinct hydrochemical water quality groups in the wairau plain groundwater system visualisation of the results of the multivariate statistical analyses and distribution of groundwater nitrate concentrations in the context of aquifer lithology highlighted the link between groundwater chemistry and the lithology of host aquifers the methodology followed in this study can be applied in a variety of hydrogeological settings to synthesise geological hydrogeological and hydrochemical data and present them in a format readily understood by a wide range of stakeholders this enables a more efficient communication of the results of scientific studies to the wider community

environmental changes and human impact on landscapes as recorded in lagoon lacustrine sequences of russky island south far east abstract diatom and pollen analyses of paleolake sediments allowed assessment of the natural and anthropogenic factors that affected the local landscape evolution over the last 7500 cal yr on russky island in south far east of russia eight stages in lagoon development mainly controlled by sea level fluctuations were inferred lagoon salinity was highest during the maximum of the holocene transgression the lagoon developed into a brackish lake at 5090 cal yr bp and became completely fresh at 4090 cal yr bp the sedimentation rate decreased around 3510 cal yr bp which coincided with a weakening of the summer monsoon a swamp formed during the last 700 years the data suggest that natural factors were the main controls on the observed changes in the landscape pollen analysis indicates periods of increased proportions of thermophilic species in the broadleaf forests pollen data indicate appearance of korean pine and fir role oak and birches and changes of the plant community on the coast first notable human impact on the vegetation coincided with the neolithic colonization of the coastal area evidence of fires between 5500 and 4920 cal yr bp was possibly associated with human activities human impact on the vegetation increased markedly in the late 19th century

sources and flow of north canterbury plains groundwater new zealand abstract geological hydrological isotope tritium and 18 o and chemical mainly nitrate and chloride concentrations evidence is interpreted to give a mutually consistent picture of the recharge sources and flow patterns of the important groundwater resource in the deep glacial and interglacial deposits of the sector of the canterbury plains between the selwyn river and ashley river particular attention is paid to the confined gravel aquifers which presently provide about 300 000 m 3 daily of mainly very high quality water for the needs of christchurch city the study period for tritium measurements extends over 27 years encompassing the peak and decline of thermonuclear tritium fallout in this region major rivers emerging from the hill and mountain catchments to the west of the plains are depleted in 18 o relative to average low level precipitation most of the groundwater is river recharged but some areas of significant local precipitation recharge contribution are clearly identified by 18 o and chemical concentrations the pressure distribution tritium and chemical data reveal that the artesian ground water underlying christchurch ascends from deeper aquifers into the shallowest aquifer via gaps in the confining layers much of this flow is induced by withdrawal and the data reveal nothing about possible offshore discharge through the seaward extension of the shallowest aquifer which is known to outcrop 40 km beyond the coast the christchurch aquifers are recharged by infiltration from waimakariri river in its central plains reaches and the resulting flow regime is east and southeast directed satisfactory water quality of the deeper christchurch aquifers appears to be guaranteed for the future provided the river can be maintained in its present condition shallow groundwater and water recharged to depth by other rivers irrigation and local precipitation on the unconfined western areas of the plains are more susceptible to agricultural and other pollutants none of this water is encountered in the deeper aquifers under christchurch but only in shallow aquifers and surface discharges or else flowing to the southeast well away from the city area

environmental tritium and 18o applied in a hydrological study of the wairau plain and its contributing mountain catchments marlborough new zealand abstract isotope data tritium and 18 o for rivers and ground water acquired since 1968 are combined with geological hydrological and hydrochemical evidence to determine sources and flow patterns of ground water in gravel aquifers of the wairau coastal plain and its southern tributary valleys determination of the components of groundwater origin depends on a strong west east gradient of 18 o concentration between mountain catchment precipitation feeding rivers flowing to the plain and rainwater falling directly on the plain the main aquifer is postglacial alluvial material deposited by wairau river deriving its water from that river locally infiltrated precipitation contributes at most only a few percent to the flow in the shallowest gravels downstream of the infiltration zone in the south of the plain the unconfined aquifer comprises material deposited during the last glaciation its ground water has both local precipitation and inflow from southern tributary streams as appreciable sources the main aquifer is confined near the coast where it is overlain by up to 60 m of marine sediments deposited during postglacial marine transgression and subsequent coastal progradation tritium concentrations show that ground water in the shallowest geological stratum rapaura gravels reaches the confined zone boundary less than 1 year after recharge from the river with much shallow flow being discharged at the surface just upstream of the boundary in contrast ground water in the underlying unit speargrass gravels requires at least 10 years to reach this point analysis of tritium concentrations in the confined zone shows a central zone through which the faster flowing rapaura component dominates as far as the coast but also areas to the north and south where ground water in the rapaura gravels has a dominant older component the combined evidence reveals that the confined ground water is leaking into the overlying sediments allowing water to flow from the lower speargrass gravels into the rapaura gravels because wairau river is the dominant source of ground water for the main aquifer its response to bomb tritium input to its mountain catchments is given detailed consideration much of the river water derives promptly from bare catchment areas but the analysis suggests that about 50 is retained for about 8 years on average before release to the river large deposits of scree in higher lying formerly glacial catchments appears to be the major factor in the surprisingly large quantity of stored water implied by this result

a four component mixing model for water in a karst terrain in south central indiana usa using solute concentration and stable isotopes as tracers the study area lies in a highly karstified carbonate terrain in south central indiana sinkholes conduits and caves form large secondary pathways for the subsurface flow as a result the discharge from a main emergence point for the subsurface flow system the orangeville rise quickly responds to the storm events and shows wide variations in flow rate water chemistry and stable isotopic compositions these responses are attributed to the mixing of water in secondary pathways in the study area recharge occurs through the thick mantled karst plain and the sinkhole plains and the role of soil layer and epikarst in the recharge process is of great importance rain dic 2 hco3 mg l 13cdic 7 soil water dic 544 hco3 mg l 13cdic 14 7 epikarstic water dic 224 hco3 mg l 13cdic 13 6 and phreatic diffuse flow water dic 299 hco3 mg l 13cdic 11 8 generally showed unique and constant dissolved inorganic carbon dic and 13cdic values over time using dic and 13cdic as tracers a four component mixing model was established for the karstic flow system by constructing the discharge hydrograph separation curves the mixing ratio of each component rain 10 6 soil 3 1 epikarstic 52 3 and phreatic 34 0 water was determined for the orangeville rise discharge over the testing period of 104 h after the storm event of 10 4 90 vadose water occupied 55 4 of spring discharge and this demonstrates the importance of the unsaturated zone especially the epikarst in the karstic flow systems

using 18o 2h 3h 3he 85kr and cfcs to determine mean residence times and water origin in the grazer and leibnitzer feld groundwater bodies austria two groundwater bodies grazer feld and leibnitzer feld with surface areas of 166 and 103 km2 respectively are characterised for the first time by measuring the combination of 18o 2h 3h 3he 85kr cfc 11 cfc 12 and hydrochemistry in 34 monitoring wells in 2009 2010 the timescales of groundwater recharge have been characterised by 131 18o measurements of well and surface water sampled on a seasonal basis most monitoring wells show a seasonal variation or indicate variable contributions of the main river mur 0 30 max 70 and or other rivers having their recharge areas in higher altitudes combined 18o 2h measurements indicate that 65 75 of groundwater recharge in the unusual wet year of 2009 was from precipitation in the summer based on values from the graz meteorological station monitoring wells downstream of gravel pit lakes show a clear evaporation trend a boron nitrate differentiation plot shows more frequent boron rich water in the more urbanised grazer feld and more frequent nitrate rich water in the more agricultural used leibnitzer feld indicating that a some of the nitrate load in the grazer feld comes from urban sewer water several lumped parameter models based on tritium input data from graz and monthly data from the river mur spielfeld since 1977 yield a mean residence time mrt for the mur water itself between 3 and 4 years in this area data from 18o 3h 3he measurements at the wagna lysimeter station supports the conclusion that 90 of the groundwaters in the grazer feld and 73 in the leibnitzer feld have mrts of 20 m with relative thicker unsaturated zones the young mrt of groundwater from two monitoring wells in the leibnitzer feld was confirmed by 85kr measurements most cfc 11 and cfc 12 concentrations in the groundwater exceed the equilibration concentrations of modern concentrations in water and are therefore unsuitable for dating purposes an enrichment factor up to 100 compared to atmospheric equilibrium concentrations and the obvious correlation of cfc 12 with so4 na cl and b in the ground waters of the grazer feld suggest that waste water in contact with cfc containing material above and below ground is the source for the contamination the dominance of very young groundwater 5 years indicates a recent origin of the contamination by nitrate and many other components observed in parts of the groundwater bodies rapid measures to reduce those sources are needed to mitigate against further deterioration of these waters

historical tsunami records on russian island the sea of japan in this article we provide data evidencing tsunamis on russian island over the last 700 years reconstructions are developed based on the analyses of peat bog sections on the coast of spokoynaya bay including layers of tsunami sands ancient beach sands under peat were deposited during the final phase of transgression of the medieval warm period we used data on diatoms and benthic foraminifers to identify the marine origin of the sands the grain size compositions of the tsunami deposits were used to determine the sources of material carried by the tsunamis the chronology of historical tsunamis was determined based on the radiocarbon dating of the underlying organic deposits there was a stated difference between the deposition environments during tsunamis and large storms during the goni 2015 and lionrock 2016 typhoons tsunami deposits from 1983 and 1993 were found in the upper part of the sections the inundation of the 1993 tsunami did not exceed 20 m or a height of 0 5 m a m s l 0 3 above high tide the more intensive tsunami of 1983 had a run up of 0 65 m a m s l and penetrated inland from the shoreline up to 40 m sand layer of tsunami 1940 extend in land up to 50 m from the present shoreline evidence of six tsunamis was elicited from the peat bog sections the deposits of which are located 60 m from the modern coastal line the deposits of strong historic tsunamis in the japan sea region in 1833 1741 1614 or 1644 1448 the xiv xv century and 1341 were also identified on russian island their run ups and inundation distances were also determined the strong historic tsunamis appeared to be more intensive than those of the xx century and considering the sea level drop during the little ice age the inundation distances were as large as 250 m

deposition models for chronological records abstract long term sedimentary sequences provide a wealth of useful information for research into the palaeo environment especially in relation to past climate change shorter records provide similar information in many archaeological contexts however if such records are to be used to provide precise timing of events and more critically the relative timing between different records methods are needed to provide accurate and precise age depth models for these sequences given the imprecision of individual calibrated radiocarbon determinations it is necessary to use the information we have about the deposition process to refine our chronologies and also to provide interpolation between dated levels in any sequence even with layer counted chronologies the uncertainties are sometimes hard to quantify this paper outlines a range of bayesian models for deposition which have been implemented in the computer programme oxcal these models can be used to combine information from the sediments themselves with radiocarbon or other direct dating information such models have the potential to integrate information between different records and provide a coherent chronology on which to base environmental or archaeological research