ice moraine and landslide dams in mountainous terrain we review recent work on ice moraine and landslide dams in mountainous terrain thus complementing several comprehensive summaries on glacier dams in intracontinental and arctic areas of low relief we discuss the roles of tectonic and climatic forcing on ice moraine and landslide dam formation and sudden drainage and focus on similarities and differences between their geomorphic impacts on confined valleys drained by steep bedrock and gravel bed rivers despite numerous reported failures of natural dams in mountain belts throughout the world their relevance to long term dynamics of mountain rivers remains poorly quantified all types of dams exert local base level controls thus trapping incoming sediment and inhibiting fluvial bedrock incision pervasive geomorphic and sedimentary evidence of outburst events is preserved even in areas of high erosion rates suggesting that sudden dam failures are characterized by processes of catastrophic valley floor aggradation active channel widening and downstream dispersion of sediment during which little bedrock erosion seems to be achieved we find that in the absence of direct evidence of former dams a number of similarities among the geomorphic and sedimentologic characteristics of catastrophic outburst flows may give rise to ambiguous inferences on the dam forming process this is especially the case for tectonically active mountain belts where there is ample and comparable potential for the formation and failure of ice moraine landslide and polygenetic dams concomitant with climatic oscillations or earthquake disturbance hence the palaeoclimatic implications of erroneously inferring the cause of dam formation may be significant we recommend that future research on natural dams in mountainous terrain addresses a climate and earthquake controlled systematics in the pattern of formation and failure b quantification of response of mountain rivers to catastrophic outburst events and their concomitant process sequences c elaboration of a comprehensive classification of natural dams in mountainous terrain with special attention to polygenetic dams d physical based modelling of dam formation failure and routing of water and sediment outbursts and e quantitative controls on the contribution of natural dams to sediment budgets in mountainous terrain

a body wave analysis of the 1966 gisborne new zealand earthquake abstract the ml 6 2 gisborne earthquake of march 4 1966 occurred along the east coast of the north island new zealand modeling of p and s body waves shows that the focal mechanism of this event is consistent with northwestward thrusting of the pacific plate beneath the north island 249 25 and 131 the focal depth is constrained to 18 km significantly less than the values of 25 30 km computed from local network data estimates of the scalar moment source duration and stress drop for the event are 4 1024 dyne cm 2 3 s and 20 120 bar respectively cross correlation errors of synthetic to observed waveforms were computed for all possible p and t axis locations and slip vector orientations and contoured on a projection of the focal sphere the error contour at which the synthetic waveforms distinctly diverged from the observed waveforms was established by eye the procedure shows that the analysis of long period body waves at least in this case provides much better constraint on focal mechanism orientation than does first motion data alone

glaciological and marine geological controls on terminus dynamics of hubbard glacier southeast alaska hubbard glacier located in southeast alaska is the world s largest nonpolar tidewater glacier it has been steadily advancing since it was first mapped in 1895 occasionally the advance creates an ice or sediment dam that blocks a tributary fjord russell fiord the sustained advance raises the probability of long term closure in the near future which will strongly impact the ecosystem of russell fiord and the nearby community of yakutat here we examine a 43 year record of flow speeds and terminus position to understand the large scale dynamics of hubbard glacier our long term record shows that the rate of terminus advance has increased slightly since 1895 with the exception of a slowed advance between approximately 1972 and 1984 the short lived closure events in 1986 and 2002 were not initiated by perturbations in ice velocity or environmental forcings but were likely due to fluctuations in sedimentation patterns at the terminus this study points to the significance of a coupled system where short term velocity fluctuations and morainal shoal development control tidewater glacier terminus position

the hawke s bay new zealand earthquake of 1982 september 02 and deformation in the interior of the subducted pacific plate abstract the most damaging earthquake to occur in new zealand in 1982 was the hawke s bay earthquake of september 02 m b 5 6 an aftershock study using portable microearthquake recorders has established that this event occurred some 20 km south of hastings at a depth of about 47 km this depth places the event in the mantle of the subducted pacific plate this earthquake is a member of a recently recognized class of intraplate shocks occurring along the strike of the subducted plate near the east coast of the north island such events are characterized by normal faulting mechanisms when taken together with activity in the crust of the subducted plate this subcrustal activity resembles a double planed seismic zone restricted in the down dip direction of the subducted plate several lines of evidence suggest that deformation in the mantle of the subducted plate is controlled by the state of coupling of the plate interface at shallow depth 1 1 the subcrustal activity occurs directly beneath the source region of major interplate earthquakes along the east coast of the north island and there appears to be a pairing of interplate and subcrustal events 2 2 stress directions determined for the subcrustal events are concordant with geodetic strain directions and 3 3 the amount of subcrustal activity appears to be related to the state of coupling of the plate interface

a review of catastrophic drainage of moraine dammed lakes in british columbia abstract moraine dammed lakes are common in the high mountains of british columbia most of these lakes formed when valley and cirque glaciers retreated from advanced positions achieved during the little ice age many moraine dams in british columbia are susceptible to failure because they are steep sided have relatively low width to height ratios comprise loose poorly sorted sediment and may contain ice cores or interstitial ice in addition the lakes commonly are bordered by steep slopes that are prone to snow and ice avalanches and rockfalls moraine dams generally fail by overtopping and incision the triggering event may be a heavy rainstorm or an avalanche or rockfall that generates waves that overtop the dam the dam can also be overtopped by an influx of water caused by sudden drainage of an upstream ice dammed lake jokulhlaup melting of moraine ice cores and piping are other possible failure mechanisms failures of moraine dams in british columbia produce destructive floods orders of magnitude larger than normal streamflows most outburst floods are characterized by an exponential increase in discharge followed by an abrupt drop to background levels when the water supply is exhausted peak discharges are controlled by dam characteristics the volume of water in the reservoir failure mechanisms and downstream topography and sediment availability for the same potential energy at the dam site floods from moraine dammed lakes have higher peak discharges than floods from glacier dammed lakes the floodwaters may mobilize large amounts of sediment as they travel down steep valleys producing highly mobile debris flows such flows have larger discharges and greater destructive impact than the floods from which they form moraine dam failures in british columbia and elsewhere are most frequent following extended periods of cool climate when large lateral and end moraines are built a period of protracted warming is required to trap lakes behind moraines and create conditions that lead to dam failure this sequence of events occurred only a few times during the holocene epoch most notably during the last several centuries glaciers built large moraines during the little ice age mainly during the 1700s and 1800s and lakes formed behind these moraines when climate warmed in the 1900s twentieth century climate warming is also responsible for recent moraine dam failures in mountains throughout the world warming from the late 1800s until about 1940 and again from 1965 to today destabilized moraine dams with interstitial or core ice the warming also forced glaciers to retreat prompting ice avalanches landslides and jokulhlaups that have destroyed some moraine dams

jokulhlaups a reassessment of floodwater flow through glaciers 1 in glaciated catchments glacier generated floods jokulhlaups put human activity at risk with large sporadic jokulhlaups accounting for most flood related fatalities and damage to infrastructure in studies of jokulhlaup hydrodynamics the view predominates that floodwater travels within a distinct conduit eroded into the underside of a glacier however some jokulhlaups produce subglacial responses wholly inconsistent with the conventional theory of drainage by focusing on icelandic jokulhlaups this article reassesses how floodwater flows through glaciers it is argued that two physically separable classes of jokulhlaup exist and that not all jokulhlaups are an upward extrapolation of processes inherent in events of lesser magnitude and smaller scale the hydraulic coupling of multiple nonlinear components to the flood circuit of a glacier can induce extreme responses including pressure impulses in subglacial drainage representing such complexity in mathematical form should be the basis for upcoming research as future modeling results may help to determine the glaciological processes behind heinrich events moreover such an approach would lead to more accurate predictive models of jokulhlaup timing and intensity

late holocene activity of sherman and sheridan glaciers prince william sound alaska abstract two adjacent glaciers in the chugach mountains of south central alaska have markedly different histories on decadal to perhaps centennial timescales sheridan glacier has advanced and retreated hundreds of metres during the latest holocene its recent fluctuations have markedly altered local base level of sherman river which drains sherman glacier and flows into sheridan lake sheridan glacier advanced to its greatest extent during the little ice age raising base level of sherman river and inducing aggradation there of up to 17 m of sediment retreat of sheridan glacier formed a series of lakes that have coalesced as lower lake outlets have become available base level of sherman river has dropped resulting in the evacuation of substantial volumes of sediment from sherman river valley in about 2000 the terminus of sheridan glacier began to disintegrate retreat accelerated dramatically in 2010 by 2016 the glacier had retreated an average of 600 m from its 2010 terminus although some areas retreated up to 1 9 km and others did not retreat at all meanwhile sherman glacier continued a slow advance initiated by a rock avalanche that blanketed much of its ablation area in the 1964 alaska earthquake

characterization of an internal slope movement structure by hydrogeophysical surveying a hydrogeophysical study was carried out by a water controlled injection within a landslide situated on an active part of the la clapiere landslide foot alpes maritimes france coupling of both real time geophysical and hydrological follow ups allowed the representation and quantification of the surface water drainage in space and time within the slipped mass thus 30 of the injected water is quickly drained by a complex slipping surface meanly situated at 10 m depth the transit time between injection and outflow of the water allowed an overloading of about 10 m3 i e 10 tons comparable with classical rain events in the area this weight and the associated interstitial pressures increase have not led to any movements asking for the origin of the water volumes which could induce destabilizations this experiment enabled an accurate redefinition of the internal slope structure and the understanding of the dynamics of the slipped mass with a surface hydraulic request

uisge meinne mine water hydrogeology in the celtic lands from kernow cornwall uk to ceap breattain cape breton canada

hydrogeological framework for assessing the possible environmental impacts of large scale gold mines abstract hydrogeological information is crucial to the development of a sound environmental impact assessment eia for a proposed mine as well as the management of potential environmental impacts during and after exploitation however the determination of hydrogeological parameters is not customarily included in mineral exploration surveys with the result that many eias end up being rather light in hydrogeological content examples from the tarkwa gold mining district of ghana illustrate this point consequences of such an inadequate hydrogeological understanding are potentially serious ranging from an inability to predict future problems in water quality after the cessation of mining to a lack of understanding of hydrogeological controls on slope stability which is arguably manifest in the catastrophic spill of cyanide rich processing effluents from a breached tailings dam at wassa west near tarkwa on 16 october 2001 to redress this deficiency we propose that a hydrogeological database be assembled during the mineral exploration phase according to a specified protocol check list using these data a rational conceptual hydrogeological model for the mine site and its surrounding area can be developed providing the basis for a thorough consideration of groundwater aspects within the statutory environmental impact assessment which is as in most other countries required by ghanaian government statute before a mining lease is approved the resources required to set up such a database are small compared to the benefits

integrated hydraulic hydrogeochemical assessment of flooded deep mine voids by test pumping at the deerplay lancashire and frances fife collieries

seasonal fluctuations in the advance of a tidewater glacier and potential causes hubbard glacier alaska usa satellite imagery has been used to acquire seasonal terminus positions of tidewater hubbard glacier alaska usa from 1992 to 2006 during this 15 year time period the width averaged advance of the entire terminus has been 620 m at a mean rate of 35 m a 1 seasonal fluctuation of the terminus ranges from 150 to 200 m on average and varies spatially a section of the terminus near a narrow gap where the glacier has now twice closed off 40 km long russell fiord exhibited little to no mean advance during this time period but displayed seasonal fluctuations of 300 500 m seasonal variability in surface ice speeds and surface sea water temperatures was also observed both are potential forcing mechanisms for terminus fluctuations seasonal changes in sea water temperature of 10 128c as well as seasonal changes in subglacial freshwater discharge are inferred to influence calving and submarine melting at the terminus driving seasonal variations displacements of the medial moraine separating hubbard and valerie glaciers at the terminus suggest surge like pulses of the latter with a periodicity of several years the timing of these pulses suggests they may influence the hubbard terminus near gilbert point and have implications for future closures of russell fiord

spatial clustering and stress drops of foreshocks of the february 1990 tennyson and weber new zealand earthquakes the ability to distinguish foreshocks from background seismicity is very important in short term earthquake prediction to that end we have looked at spatial clustering using waveform cross correlation and stress drops of foreshocks of two new zealand earthquake sequences that occurred in 1990 the tennyson sequence located in a continental margin type strike slip environment consisted of a group of foreshocks an ml 5 8 mainshock and many aftershocks a cross correlation analysis showed five spatially close clusters of activity prior to the mainshock two were event pairs located within the final aftershock zone two were clusters of four events each located outside the aftershock zone and the fifth was a cluster of eight immediate foreshocks loated within the aftershock zone an analysis of two nearby control regions showed that pairs of identical events were not uncommon but larger clusters were stress drops of three events in the 12 days before the mainshock obtained by deconvolving small events as empirical green s functions were lower than for earlier preshocks and aftershocks source time functions derived from the green s function deconvolution indicated that a unilateral rupture model was more appropriate than a circular source model cross correlation values from the ml 5 9 weber sequence also showed spatial clustering but this was well removed from the mainshock in space and time a control area also showed similar clustering suggesting that it is a normal feature of the seismicity at a convergent margin the weber foreshocks only four in all were not highly correlated for both sequences foreshocks did not correlate with the aftershocks indicating that they occurred in a region of complete coseismic stress relief a stress drop of 1650 bars was obtained for a 44 km deep event that occurred within the upper part of the subducting pacific plate nearby but not related to the tennyson sequence

sorbing tracer experiments in a crystalline rock fracture at aspo sweden 2 transport model and effective parameter estimation 1 transport and retention of sorbing tracers in a single altered crystalline rock fracture on a 5 m scale is investigated we evaluate the results of a comprehensive field study referred to as

application of fracture flow hydrogeology to acid mine drainage at the bunker hill mine kellogg idaho abstract the mechanics of groundwater flow through fractured rock has become an object of major research interest during recent years this project has investigated the flow of groundwater through fractured precambrian metaquartzite rocks in a portion of the bunker hill mine near kellogg idaho groundwater flow through these types of rocks is largely dependent upon the properties of fractures such as faults joints and relict bedding planes groundwater that flows into the mine via the fractures is acidic and is contaminated by heavy metals which results in a severe acid mine drainage problem a more complete understanding of how the fractures influence the groundwater flow system is a prerequisite of the evaluation of reclamation alternatives to reduce acid drainage from the mine fracture mapping techniques were used to obtain detailed information on the fracture properties observed in the new east reed drift of the bunker hill mine the information obtained includes fracture type orientation trace length the number of visible terminations roughness waviness infilling material and a qualitative measure of the amount of water flowing through each fracture the hydrogeologic field data collected include routine measurements of the discharge from four individual structural features and four areas where large quantities of water are discharging from vertical rock bolts the depths to water in three piezometer nests at the ground surface the pressure variations in four diamond drillholes and constant discharge flow tests conducted on three of the diamond drillholes the field data indicate that relict bedding planes are the primary conduits for groundwater flow and suggest that the two major joint sets that are present connect water flowing through the discontinuous bedding planes the three minor joint sets that are present do not seem to have a significant impact on groundwater flow but along with the two major joint sets may store relatively large quantities of water it appears that rock bolt holes in the central portion of the drift primarily intersect relict bedding planes whereas rock bolt holes in the southeastern portion of the drift primarily intersect joints this probably is related to the shallower angle of dip of the bedding planes in the central portion of the drift it also appears that recharge from the surface directly above the mined out openings is the primary source of water in the upper workings of the mine and that the large seasonal head variations in the potentiometric surface are primarily responsible for the observed temporal variations in mine inflow infilling material may control the hydrogeologic character of the faults with those filled with gouge having low hydraulic conductivities and those filled with breccia having relatively high hydraulic conductivities in addition one of the faults may act as a positive constant head recharge hydrogeologic boundary a double porosity approach probably is the most appropriate for simulating the groundwater flow system in the vicinity of the new east reed drift finally grouting of a combination of breccia filled faults and relict bedding planes may offer the best hope for minimizing mine water inflow or recharge

normal faulting through subducted oceanic crust the 19 july 1985 earthquake of hawke s bay new zealand abstract source parameters of the m l 5 7 19 july 1985 earthquake of northern hawke s bay new zealand are determined by modelling the teleseismic p and s body waves a focal depth of 31 1 km scalar moment 5 6 10 17 nm and source duration of 3 0 3 5 s are estimated the focal mechanism strike 224 dip 78 rake 273 shows normal faulting on a nw dipping plane that is parallel to the strike of the subducted pacific plate thirty five aftershocks were recorded by a temporary seismograph network 21 of which were relocated using the jhd method the hypocentres define a northwest dipping plane 20 30 km which extends from the hypocentre of the mainshock to a depth of 47 km the position of the subducted plate in hawke s bay is well defined from previous micro earthquake studies in the region of the mainshock the plate interface is located at a depth of approximately 28 to 30 km placing the hypocentre of the mainshock in the crust of the pacific plate the extent and location of the aftershock distribution suggest that the mainshock ruptured downward and extended through the crust of the plate this event thus differs from other normal faulting events in the region that usually occur in the mantle of the subducted plate the scalar moment at long periods t 45s dziewonski et al 1986 exceeds that determined here by a factor of 2 suggesting a source rich in long period energy an idea supported by the relatively large aftershock area

proglacial lakes character behaviour and geological importance proglacial lakes are ubiquitous within the quaternary record and can provide exceptional breadth and depth of palaeoenvironmental information present deglaciation is increasing the number and size of proglacial lakes around the world this study provides a synthesis of knowledge on proglacial lake character and behaviour and critically evaluates the importance of proglacial lakes from a geological perspective we show how ice marginal or ice contact lakes and other distal proglacial lakes can be distinguished from each other by geomorphological sedimentological chemical and biological characteristics the key controls on proglacial lake geomorphology and sedimentology are outlined and discussed proglacial lakes can exacerbate mountain glacier and ice sheet margin ablation via mechanical and thermal stresses but very large lakes can moderate summer air temperatures and relatively retard summer ice ablation proglacial lakes interrupt meltwater flux and are very efficient sediment traps hydrological routing and consequent geomorphological activity can be radically modified by sudden drainage of proglacial lakes and resultant glacial lake outburst floods exceptionally large proglacial lake drainages affected global ocean circulation and global climate during the quaternary overall analyses of proglacial lakes can provide a valuable insight into i patterns character and behaviour of mountain glaciers ice sheets and glaciations and ii the impacts of past present and future deglaciation

hazardous processes and events from glacier and permafrost areas lessons from the chilean and argentinean andes glacier and permafrost hazards such as glacial lake outburst floods and rock ice avalanches cause significant socio economic damages worldwide and these processes may increase in frequency and magnitude if the atmospheric temperature rises in the extratropical andes nearly 200 human deaths were linked to these processes during the twentieth century we analysed bibliographical sources and satellite images to document the glacier and permafrost dynamics that have caused socio economic damages in this region in historic time including glacial lake outburst floods ice and rock ice avalanches and lahars to unravel their causes and geomorphological impacts in the extratropical andes at least 15 ice dammed lakes and 16 moraine dammed lakes have failed since the eighteenth century causing dozens of floods some floods rank amongst the largest events ever recorded 5000 106 m3 and 229 106 m3 respectively outburst flood frequency has increased in the last three decades partially as a consequence of long term decades to centuries climatic changes glaciers shrinkage and lake growth short term days to weeks meteorological conditions i e intense and or prolonged rainfall and high temperature that increased meltwater production have also triggered outburst floods and mass movements enormous mass failures of glaciers and permafrost 10 106 m3 have impacted lakes glaciers and snow covered valleys initiating chain reactions that have ultimately resulted in lake tsunamis and far reaching 50 km flows the eruption of ice covered volcanoes has also caused dozens of damaging lahars with volumes up to 45 106 m3 despite the importance of these events basic information about their occurrence e g date causes and geomorphological impact which is well established in other mountain ranges is absent in the extratropical andes a better knowledge of the processes involved can help to forecast and mitigate these events copyright 2014 john wiley sons ltd

focal mechanisms of large earthquakes in the north island of new zealand slip partitioning at an oblique active margin we have used body wave modelling to determine the source parameters of 22 moderate to large earthquakes that have occurred along the hikurangi subduction margin and elsewhere in the north island of new zealand since 1964 we have also included events from the harvard cmt catalogue since 1977 as that catalogue contains smaller events than can be modelled with body waves we have found that shallow earthquakes occurring in the back arc taupo volcanic zone and its extension to the north show predominantly normal faulting with nodal planes parallel to the regional fabric and t axes indicating extension in a direction in agreement with geodetic measurements a normal faulting solution for the 1974 opunake earthquake is compatible with the mapping of active faults in the offshore taranaki region and the initiation depth of 17 km is close to the expected brittle ductile transition for that area earthquakes within the subducted plate at the southwestern end of the margin are dominated by down dip tension that is rotated towards the deepest part of the subducting plate further north the events in the upper part of the wadati benioff zone 200 km show pure down dip tension while this association is less obvious for the deeper events suggesting that the aseismic part of the subducting slab inferred from plate reconstructions has reached the 670 km discontinuity normal faulting earthquakes associated with plate bending below the region of interplate contact occur along the length of the margin while shallow normal faulting events also occur in the trench indicating that some slab pull propagates to that region we infer that large interplate earthquakes are not imminent because in other similar areas they are preceded by outer rise compressional events that have not been recorded in the region in historical times slip vectors of interplate thrust earthquakes indicate that the oblique plate motion across the margin is fully partitioned that is the plate interface accommodates very little transcurrent motion which is instead accommodated by faults in the overlying australian plate extensional geodetic strain has been measured across the margin in the northeast which has been regarded as unusual in view of the plate convergence we suggest that the topography at this part of the margin is too steep to be supported by the current horizontal forces due to friction on the plate interface this may have occurred due to a reduction in friction because of the subduction of seamounts and the subsequent entrapment of sediments this also being consistent with the idea of underplating at this part of the margin or due to the subduction of less buoyant crust other margins such as japan and mid america where there is known to be subduction of sediments also show extension in the forearc compressional strain observed across the margin in the southwest is more usual for a convergent margin but it does not show the partitioning we see in focal mechanisms these data might only agree after the long term compressional strain accumulation has been averaged over a complete seismic cycle large historical and palaeo earthquakes have occurred along the length of the margin associated with deformation in both the axial and the coastal ranges in addition along the length of the margin the rate of recent interplate thrust activity is low compared to margins that have a high proportion of aseismic slip these factors indicate that the entire length of this margin is capable of producing large earthquakes

the importance of pyritic roof strata in aquatic pollutant release from abandoned mines in a major oolitic berthierine chamosite siderite iron ore field cleveland uk abstract the cleveland ironstone field ne england is a major sedimentary iron orefield in which the principal ore minerals are iron silicates berthierine chamosite and carbonates siderite the siderite in this area is known to be rich in mg and mn in solid solution with fe although this ore assemblage would not normally be expected to give rise to acid mine drainage phenomena a number of discrete ferruginous mine water discharges totalling some 6 5 million litres ml day 1 have been identified flowing from abandoned underground mine workings and old spoil heaps in the ore field some of these discharges are extremely acidic ph 3 3 with total fe reaching 1220 mg l 1 at the point of first emergence to the surface most of the discharges are so highly charged with dissolved co2 that they effervesce upon degassing one of the discharges precipitates a ferroan calcite deposit which is most unusual as a mine water discharge precipitate all the other discharges precipitate more usual ferrihydrite and goethite ochres the geochemistry of these waters supports the view that oxidation of pyrite in the roof strata initiates dissolution of siderite in the old workings releasing co2 fe and mg to solution this chain of reactions results in these waters having so2 4 as their major anion from pyrite weathering with mg as the major cation except where fe exceeds mg in concentration two of the near coastal discharges have na as the major cation and elevated cl concentrations suggesting a sea water component however so4 cl ratios suggest that sea water can account for no more than 20 of these waters most of the cleveland mine waters have significant environmental impacts ranging from ecological damage to receiving water courses to flooding problems caused by the clogging of surface sewers with mine water precipitates a range of remedial measures are proposed

glacial outburst flood sediments within disenchantment bay alaska implications of recognizing marine jokulhlaup deposits in the stratigraphic record abstract glacial outburst floods have been observed or inferred in most glaciated regions of the world outburst flooding events along past ice sheet margins have been discussed as possible causes for changes in ocean circulation while subglacial lake drainage under ice sheets may influence ice sheet stability the recognition of these geologically instantaneous events in the marine sediment or rock record is critical in order to characterize the magnitude and frequency of past outburst events as well as to predict the likelihood of future occurrences in this paper we characterize outburst lithofacies and infer depositional processes from two outburst floods within disenchantment bay alaska and compare these deposits to other recognized outburst deposits within marine depositional settings here we show that the outburst deposits are lithologically similar and are composed of stratified mud sand and diamicton we interpret these facies to have been formed by sediment gravity flows and hypopycnal plume sedimentation these results show that the volume of sediment lithofacies and inferred depositional processes cannot be easily distinguished from normal sediment accumulation within the proximal temperate glacimarine depositional environment the paucity of fluvial subglacial discharge in polar glacimarine environments suggests the potential for recognition of such deposits in the antarctic

kinking of the subducting slab by escalator normal faulting beneath the north island of new zealand seismic reflection imaging shows a marked shallow kink at 12 km depth in the pacific plate beneath the central north island new zealand that coincides with 1 a decrease in the amplitude of the plate boundary reflection 2 the locus of prominent landward dipping splay thrust faults in the overlying plate and 3 the onset of seismogenesis on the subduction interface and within the subducted plate we propose that the sharp change in the dip of the plate interface is indicative of the downdip transition from stable to unstable slip regimes earthquake focal mechanisms suggest the kinking is accomplished through simple shear on reactivated normal faults in the crust of the subducted plate akin to the down stepping motion of an escalator the geological record of uplift in the overlying plate indicates the escalator has been operating for the last 7 m y

a procedure for modelling shallow dislocation sources summary expressions for displacements on the surface of a layered half space due to an arbitrary oriented shear dislocation are given in terms of generalized ray expansions useful approximations of these expressions for shallow events as recorded at teleseismic distances for realistic earth models are presented the results of this procedure are used to generate synthetic p sv and sh waveforms for various assumptions of stress drop

overview of the stability and barrier functions of the granitic geosphere at the kamaishi mine relevance to radioactive waste disposal in japan abstract the kamaishi in situ studies were carried out in order to provide a technical basis for the studies of the geological disposal of high level radioactive waste hlw in japan the studies were conducted in drifts located at ca 300 m and ca 700 m below the surface in the former kamaishi iron ore mine situated in the kurihashi granodiorite an early cretaceous granitic rock 110 120 ma in the kitakami area iwate prefecture northeastern japan the fractures identified in the kurihashi granodiorite were mainly formed during the early stages of the cooling process the mineralogical and dating data suggest that almost no new fractures have been generated since 70 60 ma ago the fractures have high porosity fracture fillings with relatively high sorption values that imply the fractured granitic rock could have a significant retardation capability for contaminant transport through the granite monitoring of hydrological and geochemical conditions of groundwater for 10 years showed that even fractured granitic rock close to the drift is not thoroughly oxidized and there are only negligible changes of hydrological conditions and groundwater geochemistry due to earthquakes this information is of considerable importance for the practical design of a hlw repository and to assess any impact of the pre closure conditions on the post closure performance of the geological repository finally the results of the study methodology and tools developed help increase confidence in the technical feasibility of geological disposal of hlw in japan

seismicity structure and tectonics of the wellington region new zealand summary the wellington region lies on the border between the pacific and australian plates the former being subducted the plate interface lies at shallow depth under the region 10 60 km so that detailed and long term monitoring of the seismicity of the zone where large thrust earthquakes are expected to occur is possible hypocentres for events recorded by a 12 station seismic network for the period 1978 1982 7231 events have been refined by the use of a threedimensional velocity model derived from a simultaneous inversion of arrival time data from 129 local events for both hypocentres and velocity the hypocentres show that the subducting pacific plate is defined by a nw dipping zone of relatively intense activity the plate interface as given by the upper envelope of this activity is offset vertically by 7 km on average along a nw se line through cook strait parallel to the direction of absolute motion of the pacific plate rather than to the direction of convergence the strike of the interface at deeper levels also changes across this line this distortion may partly reflect effects of the transition to continent continent type convergence further south within the subducting pacific plate the seismic activity defines two parallel zones separated by about 20 km the lower zone being much less active and perhaps merging with the upper zone at a depth of 80 90 km composite focal mechanisms of events in the upper zone imply predominantly down dip tension with a compression axis perpendicular to the plate interface the mechanism in the lower zone also implies down dip tension but the compression axis has rotated to be horizontal and along strike indicating a component of lateral shearing within the plate these two types of mechanism correlate well with those found previously for events at depths of 150 km or more thus it seems that the large negative buoyancy of the subducted lithosphere dominates the internal stress field throughout the length of the seismically active region the lithosphere acting as a stress guide there is no evidence for a significant number of events with mechanisms indicating thrusting along the plate interface the seismic velocity in the region corresponding to the upper seismic band is close to that typical for oceanic crust which here is probably considerably thicker than normal there is no evidence for a substantial increase in velocity down

stress directions in the shallow part of the hikurangi subduction zone new zealand from the inversion of earthquake first motions the numerous earthquakes recorded during recent dense seismograph deployments in the northern south island and southernmost north island and in the raukumara peninsula of new zealand provide an opportunity to investigate stress directions in the shallow part of the hikurangi subduction zone here we invert for the stress tensor orientation for regions within both the subducted and overlying plates using a new method that invokes the coulomb failure criterion and considers all p wave first motions together regardless of whether or not they are sufficient to define single event focal mechanisms the inversion also provides information on which of the two planes with maximum coulomb failure stress is the preferred fault plane in the crust of the subducted plate the least compressive stress 3 is closely aligned with the dip of the plate the subducted plate is acting as an efficient stress guide with slab pull from the deeper part of the plate being transmitted to shallow depths normal faulting on steeply dipping fault planes is favoured suggesting that bending of the crust of the subducted plate is accomplished through bulk simple shear akin to shuffling a vertical deck of cards in the overlying plate in the northeastern south island the greatest and least compressive stresses 1 and 3 are horizontal thus favouring strike slip faulting the orientation of 1 is close to that expected if the overlying plate is contracting in response to coupling at the underlying plate interface however sinistral motion on nw faults is favoured whereas motion on the major ne ene surface faults is predominantly dextral in the raukumara peninsula thrust faulting on steeply dipping planes is favoured in the lower part of the overlying plate and near the plate interface the stress regime at the plate interface does not favour interplate thrusting and a weak interface is required for this to occur it appears that strain in the overlying plate in both the northeastern south island and raukumara peninsula is partitioned in time conjugate faults may be active in taking up strain in the interseismic period between large events on the major faults

interplate coupling and temporal variation of mechanisms of intermediate depth earthquakes in chile we investigated the temporal variation of the mechanism of large intraplate earthquakes at intermediate depths in relation to the occurrence of large under thrusting earthquakes in chile focal mechanisms were determined for three large events 1 march 1934 m 7 1 d 120 km 20 april 1949 m 7 3 d 70 km and 8 may 1971 m w 7 2 d 150 km which occurred down dip of the great 1960 chilean earthquake m w 9 5 rupture zone the 1971 event is down dip compressional strike 12 dip 80 and rake 100 the 1949 earthquake focal mechanisms is 350 70 and 130 the data available for the 1934 event are consistent with a down dip tensional mechanism thus the two events which occurred prior to the great 1960 chilean earthquake are down dip tensional published fault plane solutions of large intermediate depth earthquakes 28 march 1965 and 7 november 1981 which occurred down dip of the valparaiso earthquakes of 1971 m w 7 8 and 1985 m w 8 0 are also down dip tensional these results suggest that before a major thrust earthquake the interplate boundary is strongly coupled and the subducted slab is under tension at intermediate depths after the occurrence of an interplate thrust event the displacement on the thrust boundary induces transient compressional stress at intermediate depth in the down going slab this interpretation is consistent with the hypothesis that temporal variations of focal mechanisms of outer rise events are due to changes of interplate coupling

hubbard glacier alaska 2002 closure and outburst of russell fjord and postflood conditions at gilbert point 1 hubbard glacier the largest temperate tidewater glacier in the world has been advancing since 1895 ad and has now twice dammed 60 km long russell fjord once in 1986 and more recently in 2002 this paper focuses on the 2002 event when a strong spring advance pushed shallow submarine proglacial sediments against gilbert point closing off russell fjord by late june as a consequence upstream ice flow decelerated from 5 m d 1 to 1 5 m d 1 with flow diverging to either side of gilbert point lake height reached 15 m asl before intense rains caused lake water to overtop the moraine dam on 14 august 2002 three cubic kilometers of water were released within 30 hours with peak discharge reaching 55 000 m3 s 1 24 hours after the flood began the discharge records for the 1986 and 2002 outbursts differ significantly and reflect differences in lake height 26 m versus 15 m and dam types ice versus moraine the 2002 outburst proceeded in two stages 1 relatively slow overtopping of the subaerial moraine with downward erosion rates of 1 2 m h 1 with little lateral expansion 2 followed by faster downward erosion of the submarine moraine up to 7 m h 1 with rapid lateral expansion of the channel by ice calving 7 m h 1 the annual average terminus position at gilbert point has remained constant since 2002 although there are seasonal variations of 100 200 m the deep channel strong tidal currents and seasonally warm ocean water appear to have prevented the advance of this segment of the terminus despite the glacier s continued advance elsewhere along its terminus sediments are slowly filling in the channel at a rate of about 4 m yr 1 and their steady accumulation may eventually trigger the next closure

a large scale flow and tracer experiment in granite 2 results and interpretation water and tracer flow has been monitored in a specially excavated drift in the stripa mine several new experimental techniques and equipment were developed and used the whole ceiling and the upper part of the walls were covered with 375 individual plastic sheets where the water flow into the drift could be collected eleven different tracers were injected at distances between 11 and 50 m from the ceiling of the drift the flow rate and tracer monitoring was kept up for more than 2 years the tracer breakthrough curves and flow rate distributions were used to study the flow paths velocities hydraulic conductivities dispersivities and channeling effects in the rock in a companion paper the experimental design and performed experiments are described the present paper describes the interpretation of flow and tracer movement in the rock outside the drift the tracer movement was measured by the more than 160 individual tracer curves the tracer experiments have permitted the flow porosity and dispersion to be studied the possible effects of channeling and the diffusion of tracers into stagnant waters in the rock matrix and in stagnant waters in the fractures have also been addressed

numerical simulation of the paleohydrology of glacial lake oshkosh eastern wisconsin usa abstract proglacial lakes formed during retreat of the laurentide ice sheet evolved quickly as outlets became ice free and the earth deformed through glacial isostatic adjustment with high resolution digital elevation models dems and gis methods it is possible to reconstruct the evolution of surface hydrology when a dem deforms through time as predicted by our model of viscoelastic earth relaxation the entire surface hydrologic system with its lakes outlets shorelines and rivers also evolves without requiring assumptions of outlet position the method is applied to proglacial lake oshkosh in wisconsin 13 600 to 12 900 cal yr bp comparison of predicted to observed shoreline tilt indicates the ice sheet was about 400 m thick over the great lakes region during ice sheet recession each of the five outlets are predicted to uplift more than 100 m and then subside approximately 30 m at its maximum extent lake oshkosh covered 6600 km2 with a volume of 111 km3 using the hydrologic engineering center river analysis system model flow velocities during glacial outburst floods up to 9 m s and peak discharge of 140 000 m3 s are predicted which could drain 33 5 km3 of lake water in 10 days and transport boulders up to 3 m in diameter

catastrophic flooding from glacial lake wisconsin abstract glacial lake wisconsin was a large proglacial lake that formed along the southern margin of the laurentide ice sheet during the wisconsin glaciation it was formed when ice of the green bay lobe came into contact with the baraboo hills in southwestern wisconsin and blocked the south flowing wisconsin river during early glacial recession the ice dam failed catastrophically and the lake drained in about a week despite early recognition of the former lake and the likelihood that it failed catastrophically outflow rates during the failure have not been previously evaluated estimates based on step backwater modeling indicate that peak discharge was between 3 6 and 5 3 10 4 m 3 s in the lower wisconsin river as an alternate method we used a previously derived empirical relationship between lake volume and peak discharge for dam break events from a digital elevation model altered to incorporate isostatic depression we estimated the lake volume to be 87 km 3 just prior to dam breach suggesting that the flooding magnitude was as high as 1 5 10 5 m 3 s at the outlet adjusting these results for downstream flood wave attenuation gives a discharge of around 4 4 10 4 m 3 s in the lower reach which closely matches the results of the step backwater modeling these estimates of discharge from the catastrophic failure of ice marginal lakes improve our understanding of the processes that have produced the morphology and behavior of present day upper midwest river systems

flow dynamics of tidewater glaciers a numerical modelling approach the dynamics of grounded tidewater glaciers is investigated with a time dependent numerical flow model which solves the full equations for the stress and velocity fields and includes a water pressure dependent sliding law the calving criterion implemented in the model shifts the calving front at each time step to the position where the frontal ice thickness exceeds flotation height by a prescribed value with this model the linear relation between calving rate and water depth proposed on empirical grounds is qualitatively reproduced for the situation of a slowly retreating or advancing terminus but not for situations of rapid changes length changes of tidewater glaciers i e especially rapid changes are dominantly controlled by the bed topography and are to a minor degree a direct reaction to a mass balance change thus accurate information on the near terminus bed topography is required for reliable prediction of the terminus changes due to climate changes the results also confirm the suggested cycles of slow advance and rapid retreat through a basal depression rapid changes in terminus positions preferably occur in places where the bed slopes upwards in the ice flow direction

multi decadal elevation changes on bagley ice valley and malaspina glacier alaska 1 digital elevation models dems of bagley ice valley and malaspina glacier produced by i intermap technologies inc iti from airborne interferometric synthetic aperture radar insar data acquired 4 13 september 2000 ii the german aerospace center drl from spaceborne insar data acquired by the shuttle radar topography mission srtm 11 22 february 2000 and iii the us geological survey usgs from aerial photographs acquired in 1972 73 were differenced to estimate glacier surface elevation changes from 1972 to 2000 spatially non uniform thickening 10 7 m on average is observed on bagley ice valley accumulation area while non uniform thinning 47 5 m on average is observed on the glaciers of the malaspina complex mostly ablation area even larger thinning is observed on the retreating tidewater tyndall glacier these changes have resulted from increased temperature and precipitation associated with climate warming and rapid tidewater retreat

morainal bank progradation and sediment accumulation in disenchantment bay alaska response to advancing hubbard glacier 1 morainal banks are primary features at the margins of advancing and stable to quasi stable temperate tidewater glaciers yet their roles in glacier dynamics and terminus stability are poorly defined by submarine observations analysis of new and archival multibeam data and landsat images of the advancing hubbard glacier southeast alaska reveal that between 1978 and 2010 the ice face and morainal bank advanced together at an average rate of 34 m yr varying spatially and temporally between 14 and 80 m yr morphological features including gullies and a boulder lag suggest cyclical deposition and gravitational erosion on the proximal slope of the morainal bank 15 18 and possible ice pushing in an area without recent sedimentation in contrast the morainal bank of the nearby quasi stable surging turner glacier advanced steadily since 1978 by proximal sedimentation on the steep fjord wall below its hanging valley sedimentation in the deep 220 m basin of disenchantment bay increased from 0 88 m yr spanning 1978 to 1999 to 1 22 m yr thereafter this change appears to be a combined response to glacier advance and sediment dispersal farther down fjord and to an increase in sediment yield from other glacial and non glacial sources analysis of hubbard glacier illustrates the direct correlation between movement of the terminus and morainal bank in advancing the grounding line of a marine terminating glacier and that morainal banks provide a fundamental stabilizing role for advance into a deep water fjord compensating for changes in water depth at the grounding line

non sorbing tracer migration experiments in fractured rock at the kamaishi mine northeast japan this paper describes the design implementation and analysis of in situ tracer migration experiments in fractured granite the research highlights the importance of geo hydraulic investigations prior to performing tracer migration experiments the authors conducted a detailed but simple investigation in order to understand the spatial distribution of conductive fractures and the pressure field seven boreholes were drilled in the test area revealing hydraulic compartmentalization and a heterogeneous distribution of conductive features after identifying several suitable conductive fractures three sets of dipole tracer migration experiments were conducted with various combinations of injection and withdrawal hole and dipole ratios the tracer breakthrough curves were analyzed using a streamline analytical solution and numerical analysis of mass transport best fit calculations of the experimental breakthrough curves were obtained by assigning apertures within the range of one to ten times the square root of transmissivity and a dispersion coefficient equal to one tenth of the migration length

source parameters of large historical 1918 1962 earthquakes south island new zealand we have studied 18 earthquakes of m w 5 5 within the north island new zealand region to determine fault parameters for earthquake hazards and regional tectonic studies since most large m w 6 5 earthquakes in the north island occurred prior to 1961 these events provide important information to supplement studies of more recent seismicity our results indicate that no large plate interface earthquakes have occurred in the central and southern north island for the past 80 years although six strike slip earthquakes of m w 6 8 occurred within the australian upper plate during an extremely active 25 year period that began in 1917 only the m w 7 2 strike slip events were associated with surface faulting indicating the difficulties that may arise in attempting to identify active faults within this region two earthquakes m w 6 9 7 1 off the northeastern north island in 1947 appear to have occurred along the plate interface and were associated with local tsunamis having runup heights of up to 10 m two m w 6 8 events also occurred within the pacific lower plate highlighting the hazards related to intraslab events slip vectors for the earthquakes studied suggest that the majority of transcurrent motion along the plate margin is accommodated within the australian plate similar to the results obtained from studies of more recent smaller earthquakes pure thrusting occurs along the plate interface and t axes of intraslab events indicate downdip tension in the pacific plate

outburst floods from glacier dammed lakes the effect of mode of lake drainage on flood magnitude published accounts of outburst floods from glacier dammed lakes show that a significant number of such floods are associated not with drainage through a tunnel incised into the basal ice the process generally assumed but rather with ice marginal drainage mechanical failure of part of the ice dam or both non tunnel floods are strongly correlated with formation of an ice dam by a glacier advancing from a tributary drainage into either a main river valley or a pre existing body of water lake or fiord for a given lake volume non tunnel floods tend to have significantly higher peak discharges than tunnel drainage floods statistical analysis of data for floods associated with subglacial tunnels yields the following empirical relation between lake volume v and peak discharge qp qp 46v0 66 r2 0 70 when qp is expressed in metres per second and v in millions of cubic metres this updates the so called clague mathews relation for non tunnel floods the analogous relation is qp 1100v0 44 r2 0 58 the latter relation is close to one found by costa 1988 for failure of constructed earthen dams this closeness is probably not coincidental but rather reflects similarities in modes of dam failure and lake drainage we develop a simple physical model of the breach widening process for non tunnel floods assuming that 1 the rate of breach widening is controlled by melting of the ice 2 outflow from the lake is regulated by the hydraulic condition of critical flow where water enters the breach and 3 the effect of lake temperature may be dealt with as done by clarke 1982 calculations based on the model simulate quite well outbursts from lake george alaska dimensional analysis leads to two approximations of the form qp vqf hi 0 where q 0 5 to 0 6 hi is initial lake depth 0 is lake temperature and the form of f hi 0 depends on the relative importance of viscous dissipation and the lake s thermal energy in determining the rate of breach opening these expressions along with the regression relations should prove useful for assessing the probable magnitude of breach type outburst floods

subduction and back arc activity at the hikurangi convergent margin new zealand the hikurangi margin is a region of oblique subduction with northwest dipping intermediate depth seismicity extending southwest from the kermadec system to about 42 s the current episode of subduction is at least 16 20 ma old the plate convergence rate varies along the margin from about 60 mm a at the south end of the kermadec trench to about 45 mm a at 42 s the age of the pacific lithosphere adjacent to the hikurangi trench is not known

slug tests in fissured aquifers a simple model of a slug test in a fissured aquifer has been studied in order to gain insight into the difficulties of interpreting data from such tests the model is used to estimate the errors that would result from applying the standard type curve analysis to fissured aquifers it is found that the derived aquifer transmissivity will always be overestimated but by a factor which is unlikely to exceed 3 by contrast the derived storage coefficient can be in error by a factor ranging from 10 6 to 105 the volume of the aquifer influenced by a slug test is investigated and a simple formula for estimating the range of a test is suggested

water flow through temperate glaciers understanding water movement through a glacier is fundamental to several critical issues in glaci ology including glacier dynamics glacier induced floods and the prediction of runoff from glacierized drainage basins to this end we have synthesized a conceptual model of water movement through a temper ate glacier from the surface to the outlet stream pro cesses that regulate the rate and distribution of water input at the glacier surface and that regulate water movement from the surface to the bed play important but commonly neglected roles in glacier hydrology where a glacier is covered by a layer of porous perme able firn the accumulation zone the flux of water to the glacier interior varies slowly because the firn tempo rarily stores water and thereby smooths out variations in the supply rate in the firn free ablation zone in con trast the flux of water into the glacier depends directly on the rate of surface melt or rainfall and therefore varies greatly in time water moves from the surface to the bed through an upward branching arborescent net work consisting of both steeply inclined conduits formed by the enlargement of intergranular veins and gently inclined conduits spawned by water flow along the bottoms of near surface fractures crevasses engla cial drainage conduits deliver water to the glacier bed at a limited number of points probably a long distance downglacier of where water enters the glacier englacial conduits supplied from the accumulation zone are quasi steady state features that convey the slowly varying water flux delivered via the firn their size adjusts so that they are usually full of water and flow is pressurized in contrast water flow in englacial conduits supplied from the ablation area is pressurized only near times of peak daily flow or during rainstorms flow is otherwise in an open channel configuration the subglacial drainage system typically consists of several elements that are distinct both morphologically and hydrologically an up glacier branching arborescent network of channels in cised into the basal ice conveys water rapidly much of the water flux to the bed probably enters directly into the arborescent channel network which covers only a small fraction of the glacier bed more extensive spatially is a nonarborescent network which commonly includes cav ities gaps between the glacier sole and bed channels incised into the bed and a layer of permeable sediment the nonarborescent network conveys water slowly and is usually poorly connected to the arborescent system the arborescent channel network largely collapses during winter but reforms in the spring as the first flush of meltwater to the bed destabilizes the cavities within the nonarborescent network the volume of water stored by a glacier varies diurnally and seasonally small temper ate alpine glaciers seem to attain a maximum seasonal water storage of 200 mm of water averaged over the area of the glacier bed with daily fluctuations of as much as 20 30 mm the likely storage capacity of subglacial cavities is insufficient to account for estimated stored water volumes so most water storage may actually occur englacially stored water may also be released abruptly and catastrophically in the form of outburst floods

shallow subduction tectonics and fault interaction the weber new zealand earthquake sequence of 1990 1992 a series of four large earthquakes with epicenters very close to one another occurred in 1990 1992 in the weber region of the southeast coast of the north island new zealand the region is one of oblique plate convergence and subduction the plate interface being at about 20 km depth the first event february 19 1990 ml 6 1 mw 6 2 occurred within the upper part of the subducting pacific plate on a steeply northwest dipping normal fault as defined by relocated aftershocks the mechanism of this event reflects downdip tension within the subducting plate due to slab pull forces as is common in new zealand the second event may 13 1990 ml 6 2 mw 6 4 occurred on an imbricate fault in the overlying australian plate dipping shallowly northwest with components of both thrusting and dextral strike slip motion the slip vector is similar to the direction of plate convergence showing no arc normal rotation as observed for subduction thrust events in other areas of oblique convergence it is unlikely that the spatial and temporal closeness of these events is coincidence a similar pair occurred to the south in 1942 but the coupling mechanism is not clear perhaps being related to aseismic slip downdip on the subduction interface two subsequent events both of ml 5 5 occurred on august 15 1990 and march 2 1992 and extended the aftershock zone of the deeper first main shock to the northeast matching the extent of the shallower second main shock mechanisms of aftershocks of the two larger events are quite variable but as a whole are similar to the relevant mainshock the time history of the aftershocks of the first deeper event shows a period of quiescence beginning 35 days before the second shallow event the mean magnitude of those events that did occur was high this observation cannot be explained by station biases weather or changes in analysis methods and may be due to stress changes induced by precursory aseismic slip which would discourage aftershock occurrence

geostatistics based regional characterization of groundwater chemistry in a sedimentary rock area with faulted setting sophisticated modeling of a hydrogeological structure and the environment are crucial for underground construction this study characterizes hydrochemical properties of groundwater in a sedimentary rock area clarifying their spatial distribution and correlation with geologic structure and interpreting the groundwater source and chemical evolution water samples geological columns and well logs to 1 km depth were taken at 10 sites in horonobe of northern japan toward the objectives a 3d model of cl concentration was produced in conjunction with resistivity logging data through kriging estimation and sequential gaussian cosimulation variography shows that the dip of the main omagari fault is a control on the spatial correlation structure of cl concentration the 3d model shows that this fault and its auxiliary constitute a clear boundary between high and low saline waters and that cl concentrations tend to change in accord with sedimentary layer structures the integration of stable isotope analysis suggests that deep saline water with heavy d and 18o originated from fossilized seawater whereas shallow freshwater with light values is of meteoric water origin dilute saline water in the deep part of study area is partially attributable to dehydration of silica minerals vertical and lateral groundwater flows are estimated to prevail near the omagari fault and be general in other zones respectively difference in the depth of transition zones may be caused by the dominant flow among downward ascending and lateral consequently geostatistical techniques and data integration are useful to depict regional groundwater systems with a data set of water investigation limited by quantity and location

younger dryas glaciomarine sedimentation push moraine formation and ice margin behavior in the middle swedish end moraine zone west of billingen central sweden abstract new highway exposures and drilling reveal the stratigraphy and structure of the middle swedish end moraine zone west of billingen sweden the material in the end moraines is primarily glaciomarine clay of younger dryas age that was deposited as varved clay in front of the retreating glacier and then pushed glaciotectonically to form push moraines during minor ice margin oscillations during overall retreat during the younger dryas cold event the moraines are composed of deformed and remobilized clay with some clayey diamicton and penecontemporaneously deposited and deformed sand between the moraines lie intermoraine flats composed of undeformed varved clay of younger dryas age and surface sands of younger dryas to early holocene age based on estimations of moraine volume sedimentation rate and ice margin retreat rates we calculate the overall ice margin retreat and end moraine construction to span 350 800 years within the younger dryas because the number of moraines in the middle swedish end moraine zone varies across sweden we regard the individual oscillations west of billingen to be driven by local physical and glaciologic factors rather than ice sheet wide climate drivers the study area is also the location of the early and final drainages of the baltic ice lake the final drainage of the baltic ice lake took place several decades after the youngest moraine was formed we consider it likely that the earlier allerod drainage of the baltic ice lake bil also took place at billingen despite the lack of clear local stratigraphic evidence however based on our model a retreat driven solely by climate would not have exposed the outlet at billingen and we propose a dynamic break up of the ice margin likely centered on valle harad that was driven by the head difference between the bil and the sea

a large scale flow and tracer experiment in granite 1 experimental design and flow distribution this paper describes the stripa three dimensional experiment where water and tracer flow has been monitored in a specially excavated drift in the stripa mine several new experimental techniques and equipment were developed and used the experiment was performed in a specially excavated drift 100 m long at the 360 m level in granite the whole ceiling and the upper part of the walls were covered with 375 individual plastic sheets where the water flow into the drift could be collected eleven different tracers were injected at distances between 11 and 50 m from the ceiling of the drift the flow rate and tracer monitoring was kept up for more than 2 years the tracer breakthrough curves and flow rate distributions were used to study the flow paths velocities hydraulic conductivities dispersivities and channeling effects in the rock this paper describes the experimental techniques the fracture mapping the tracer and flow rate measurements and the results of the flow rate measurements the detailed observations made possible by the plastic sheeting technique have given some qualitative as well as quantitative information on flow rate distribution in fractured rock which previously has not been available these observations may be of importance for assessing the transport of dissolved species such as radionuclides through fractured rock

holocene history of hubbard glacier in yakutat bay and russell fiord southern alaska stratigraphic and geomorphic data defined by radiocarbon ages tree ring dates and historical observations provide evidence of three major holocene expansions of hubbard glacier early in each advance the hubbard glacier margin blocked russell fiord to create russell lake raising base level and causing stream beds and fan deltas throughout the russell drainage basin to aggrade each hubbard glacier expansion continued with an ice lobe advancing through disenchantment and yakutat bays in the west and an eastern lobe advancing into russell fiord the earlier two holocene expansions were respectively under way at 7690 and 5600 calibrated yr b p and each advance culminated more than 1 k y later the late holocene advance was under way by 3100 yr ago and reached 13 km farther south in russell fiord than the preceding two expansions late holocene deglaciation of yakutat and disenchantment bays was complete before a d 1791 nunatak glacier flowing from neves east of russell fiord became the primary ice source to the russell fiord lobe at or before this date ice retreat from the southern end of russell fiord began in the late eighteenth century and the penultimate russell lake drained ca a d 1860 the relatively slow advances and more rapid retreats of hubbard glacier are consistent with the model of the iceberg calving glacier cycle hubbard glacier is currently advancing and will likely reestablish russell lake in the near future affecting local fisheries however glacier lobes are unlikely to reach the area of the town of yakutat built on late holocene glacial deposits in the next 1 k y