wave dispersion study for tsunami propagation in the sea of marmara in this paper the aim is to investigate whether there are differences between the dispersion and non dispersion solutions on tsunami propagation for this purpose two numerical models of tsunami propagation are compared one of these numerical models is a nondispersive model that uses saint venant equations and the other is a dispersive model that uses boussinesq equations the tsunamis resulting from a submarine mass failure smf which is settled at the bottom of the north eastern sea of marmara are examined an analytical solution considering wave dispersion is developed for obtaining near field tsunami amplitudes above the submarine mass failure numerical modeling is used at the sea surface from the common boundary called as liquid boundary with incident waves up to the coastal regions to get the tsunami amplitudes the output of the analytical model is taken as the disturbances for the numerical method in the numerical solutions telemac 2d software system is used for both dispersive and nondispersive modeling the results of the dispersive and nondispersive models are compared to each other both temporal and spatial differences in the amplitudes and wave shapes are examined the obtained results demonstrate that there are no noticeable differences between the dispersion and non dispersion solutions except some special cases and some special landslide velocities

sandy beaches contamination by arsenic a result of nearshore sediment diagenesis and transport brazilian coastline abstract we studied the distribution of as fe ca and al in beach sands and near shore surface sediments along the brazilian coast from the equatorial zone to rio de janeiro state high concentrations of as up to 120 mg kg 1 exceeding the environmentally acceptable thresholds were found in the beach sands and near shore surface sediment in several segments of the studied coast that increased from north to south the significant positive correlation r 2 0 58 between as and calcium carbonate in the beach sands corroborated the hypothesis that calcareous bioclasts participate in metalloid retention and its accumulation in beach sediments most likely enrichment of as occurs in the oxic horizon of sediments caused by the diagenetic redistribution of various elements enrichment of as in beach sands occurs in the coast of bahia and espirito santo states that is facilitated by clastic material of calcareous algae

acid drainage at the inactive santa lucia mine western cuba natural attenuation of arsenic barium and lead and geochemical behavior of rare earth elements abstract a detailed geochemical study was conducted at the inactive zn pb mine of santa lucia in western cuba the studied mine wastes are characterized by high total concentrations of potentially toxic elements pte with average values of 17 4 fe 5 47 ba 2 27 pb 0 83 zn 1724 mg kg as and 811 mg kg cu oxidation of sulfide minerals in mine waste dumps and in the open pit produces acid mine effluents ph 2 5 2 6 enriched in dissolved so 4 2 up to 6754 mg l fe up to 4620 mg l and zn up to 2090 mg l low ph values 2 5 2 8 and high dissolved concentrations of the same pte were found in surface waters up to 1500 m downstream from the mine nevertheless concentrations of as ba and pb in acid mine effluents and impacted surface waters are relatively low 0 01 0 3 mg l as 0 002 0 03 mg l ba and 0 3 4 3 mg l pb analysis by x ray diffraction and electron microscopy revealed the occurrence of lead bearing barite and beudantite and the more common solid phases reported elsewhere in similar environments including fe oxyhydroxides jarosite anglesite and plumbojarosite because the reported solubilities for barite and beudantite are very low under acidic conditions these minerals may serve as the most important control in the mobility of as ba and pb in contrast fe oxyhydroxides are relatively soluble under acidic conditions and therefore they may have a less significant role in pte on site immobilization mine wastes and stream sediments show a light ree lree and middle ree mree enrichment relative to heavy ree hree in contrast acid mine effluents and surface waters are enriched in hree relative to lree these results suggest that the lree released during the oxidation of sulfides are captured by secondary weathering minerals while the mree are removed from the altered rocks the low concentrations of lree in acid stream water suggest that these elements can be retained in the sediments more strongly than hree and mree one possible explanation for the sharp decrease in dissolved lree might be their retention by low solubility secondary minerals such as anglesite barite and jarosite

tsunamis in the sea of marmara historical documents for the past models for the future abstract more than 30 tsunami events have impacted the coasts of the sea of marmara in the past two millennium clustering in izmit bay the shores of istanbul gemlik bay the shores of the kapidag and gelibolu peninsulas with respect to the last well known tsunami the izmit tsunami of 17 august 1999 available field survey run up data and marine surveys provide an opportunity to evaluate how these events were triggered the main purpose of this study is to determine the slope failure potential as a possible tsunamigenic source in the sea of marmara by utilising multi beam bathymetry shallow and deep seismic reflection data on the basis of the landslide geomorphology the generation propagation and coastal amplifications of tsunamis related to earthquake and slope failure scenarios were tested by using tsunami simulation model two layer the maximum water surface elevations near the shores along the north and south coasts are obtained according to the selected scenarios of tsunami generation by using available data

arsenic and metal mobility from au mine tailings in rodalquilar almeria se spain in the old mining area of rodalquilar mine wastes soil and sediments were characterized and the results revealed high concentration of au ag as bi cu fe mn pb se sb and zn in tailings and sediments the contaminant of greatest environmental concern is as the mean concentration in the tailings was 679 9 and 345 mg kg in the sediments of playazo creek the groundwater samples from the alluvial aquifer showed high concentration of al as cd fe hg mn ni pb se sb and zn and very high concentration of chloride and sulfate which were above the concentration defined in the european standards for drinking water the presence of as in groundwater may be caused by the oxidation of arsenian pyrite the possible as desorption from goethite and ferrihydrite and the jarosite dissolution groundwater concentrations of cd fe mn and possibly cu were associated with low values of eh indicating the possible dissolution of oxy hydroxides of fe and mn the mobility of metals in the column experiments show the release of al fe mn cr cu ni v and zn in significant concentrations but below the detected values in groundwater however as cd sb se pb and au are generally mobilized in concentrations above the detected values in groundwater the possible mass transfer processes that could explain the presence of the contaminants in the aquifer and the leachates was simulated with the phreeqc numerical code and revealed the possible dissolution of the following mineral phases jarosite natrojarosite arsenian pyrite alunite chlorite kaolinite and calcite

numerical modeling of an underwater bingham plastic mudslide and the waves which it generates underwater landslides are a common source of tsunamis in coastal areas theoretical and experimental studies on this problem however are scarce because of the difficulties in modeling and observing a submarine slide and the associated tsunami to study this problem we present a numerical model that simulates the coupling of a bingham plastic mudslide on a gentle uniform slope with the surface waves which it generates a formulation of the dynamics of the problem is presented where the landslide is treated as an incompressible bingham plastic flow and the water motion is assumed irrotational the long wave approximation is adopted for both water waves and the mudslide dispersion of waves and potential turbulent mixing are not considered the resulting differential equations are solved by a finite difference method we present the numerical results for successive profiles of the mud surface the horizontal velocity distributions of the slide the evolution of the surface elevations and the distributions of the particle velocity of the water motion three major parameters dominate the magnitude of the waves if the volume of the mud is fixed the density of mud the yield stress of the mud and the depth of water at the mudslide site because of the yield stress the slides stop on the slope when the shear stress exerted on the bottom become smaller than the yield stress the bingham plastic behavior of the mud significantly reduces the extent and the speed of the mudslide and also the magnitude of the surface waves generated comparison of the solution of the bingham plastic mudslide model with a snow flow test is presented the solution of a viscous fluid model has been derived as a special case of the present solution

propagation of distant tsunamis over slowly varying topography 1 a new two dimensional finite difference numerical scheme is developed to simulate the propagation of distant tsunamis over slowly varying topography with improved dispersion effect of waves the new scheme solves the shallow water equations on a uniform grid system however the actual computation is made on a hidden grid system whose grid size is adjustable according to the condition required to satisfy local dispersion relationships of waves for varying water depth the present model is tested for the cases of two dimensional propagation of an initial gaussian hump over various uniform water depth regions for a varying topography a one dimensional test is conducted the tests show that accuracy of the numerical model is improved significantly over that of the conventional finite difference models finally the present model is applied to the simulation of a historical tsunami event the numerical result shows that the submerged rise and ridge play an important role of a waveguide for the tsunamis propagating over that topography

hydrogeomorphic processes of thermokarst lakes with grounded ice and floating ice regimes on the arctic coastal plain alaska thermokarst lakes cover 20 of the landscape throughout much of the alaskan arctic coastal plain acp with shallow lakes freezing solid grounded ice and deeper lakes maintaining perennial liquid water floating ice thus lake depth relative to maximum ice thickness 1 5 2 0 m represents an important threshold that impacts permafrost aquatic habitat and potentially geomorphic and hydrologic behaviour we studied coupled hydrogeomorphic processes of 13 lakes representing a depth gradient across this threshold of maximum ice thickness by analysing remotely sensed water quality and climatic data over a 35 year period shoreline erosion rates due to permafrost degradation ranged from 0 2 m year in very shallow lakes 0 4 m up to 1 8 m year in the deepest lakes 2 6 m this pattern of thermokarst expansion masked detection of lake hydrologic change using remotely sensed imagery except for the shallowest lakes with stable shorelines changes in the surface area of these shallow lakes tracked interannual variation in precipitation minus evaporation p el with periods of full and nearly dry basins shorter term 2004 2008 specific conductance data indicated a drying pattern across lakes of all depths consistent with the long term record for only shallow lakes our analysis suggests that grounded ice lakes are ice free on average 37 days longer than floating ice lakes resulting in a longer period of evaporative loss and more frequent negative p el these results suggest divergent hydrogeomorphic responses to a changing arctic climate depending on the threshold created by water depth relative to maximum ice thickness in acp lakes copyright 2011 john wiley sons ltd

high resolution seismic profiling in the sea of marmara northwest turkey late quaternary sedimentation and sea level changes high resolution sparker seismic profiling was carried out in the sea of marmara northwest turkey to study the late quaternary tectonics and sedimentation of this important active basin at the western end of the north anatolian fault zone a sedimentary unit interpreted as the clinoforms of a prograding delta was observed in places along the outer part of the southern shelf the topset foreset transitions of the latest clinoforms cluster around 100 m below present sea level they were probably deposited during the last glacial maximum and early phase of deglaciation between 25 and 13 k y b p when the level of the aegean was below that of the dardanelles sill 60 70 m below sea level at present therefore the sea of marmara was isolated from the aegean during the last glacial maximum but it is possible that a fluvial overflow existed across the dardanelles during this time stabilizing the level of the marmara lake and allowing the delta progradation rivers that drain into the sea of marmara from the south have a much greater combined drainage basin area and sediment flux than those draining the region to the north this may explain the much broader shelf to the south half graben bounded by north dipping normal faults observed within the southern shelf would tend to trap sediment sourced from the south and subdue any sea bed morphology on the shelf

increasing arsenic mobility in the fine fraction of the dry stream sediments of the semi arid san antonio gold mining district baja california peninsula mexico the geochemical mobility of arsenic and some metals in the fine fraction of 20 alluvial sediment samples collected along the thalweg of the san antonio arroyo was assessed in the abandoned gold mining district of the semi arid southeastern baja california peninsula acid digested element concentrations were determined by treating the fine fraction of the sediments with concentrated hno3 via microwave heating a separate leaching of the diluted acid soluble as and some metals from the samples was carried out using 1 m hcl the most reactive as phase was extracted from the subsamples using an ascorbic solution of na citrate buffered at ph 8 the high abundance of sulphosalts tennantite cu12as4s13 and proustite ag3ass3 in the sediments from the head of the arroyo changes downstream to the predominance of arsenic trioxide arsenolite as2o3 and arsenate scorodite feaso4 2h2o acid digested as concentrations were always found to be high 230 270 mg kg 1 from the san antonio village until the end of the arroyo the concentration of reactive as and its relative contribution increased from low values of 2 3 mg kg 1 and 1 respectively at the upstream of the arroyo to 191 220 mg kg 1 and 75 89 in the middle and lower parts and is probably a result of as release from the mineral sulfide fraction of the tailings metallic contaminants exhibited different behavior with a peak of acid digested and diluted acid leached concentrations observed in the central part of the arroyo and an almost permanent geochemical mobility

thermokarst lake to lagoon transitions in eastern siberia do submerged taliks refreeze as the arctic coast erodes it drains thermokarst lakes transforming them into lagoons and eventually integrates them into subsea permafrost lagoons represent the first stage of a thermokarst lake transition to a marine setting and possibly more saline and colder upper boundary conditions in this research borehole data electrical resistivity surveying and modelling of heat and salt diffusion were carried out at polar fox lagoon on the bykovsky peninsula siberia polar fox lagoon is a seasonally isolated water body connected to tiksi bay through a channel leading to hypersaline waters under the ice cover the boreholes in the centre of the lagoon revealed floating ice and a saline cryotic bed underlain by a saline cryotic talik a thin ice bearing permafrost layer and unfrozen ground the bathymetry showed that most of the lagoon was ice grounded in spring in bedfast ice areas the electrical resistivity profiles suggest that an unfrozen saline layer was underlain by a thick layer of refrozen talik the modelling suggests thermokarst lake taliks refreeze when submerged in saltwater with mean annual bottom water temperatures below or slightly above 0 c this occurs because the top down chemical degradation of newly formed ice bearing permafrost is slower than the cooling of the talik hence lagoons may pre condition taliks with a layer of ice bearing permafrost before encroachment by the sea and this frozen layer may act as a cap on gas migration out of the underlying talik

shifting balance of thermokarst lake ice regimes across the arctic coastal plain of northern alaska 1 the balance of thermokarst lakes with bedfast and floating ice regimes across arctic lowlands regulates heat storage permafrost thaw winter water supply and over wintering aquatic habitat using a time series of late winter synthetic aperture radar sar imagery to distinguish lake ice regimes in two regions of the arctic coastal plain of northern alaska from 2003 2011 we found that 18 of the lakes had intermittent ice regimes varying between bedfast ice and floating ice conditions comparing this dataset with a radar based lake classification from 1980 showed that 16 of the bedfast ice lakes had shifted to floating ice regimes a simulated lake ice thinning trend of 1 5 cm yr since 1978 is believed to be the primary factor driving this form of lake change the most profound impacts of this regime shift in arctic lakes may be an increase in the landscape scale thermal offset created by additional lake heat storage and its role in talik development in otherwise continuous permafrost as well as increases in over winter aquatic habitat and winter water supply

numerical simulation of permafrost thermal regime and talik development under shallow thaw lakes on the alaskan arctic coastal plain 1 thaw lakes are one of the most obvious manifestations of the hydrological system at work in the tundra regions of the alaskan arctic coastal plain but the extent of the role of thaw lakes in arctic land atmosphere interactions and feedback has yet to be fully understood this study uses a two dimensional heat transfer model with phase change under a cylindrical coordinate system to simulate the long term influence of shallow thaw lakes on the thermal regime of permafrost and talik development on the alaskan arctic coastal plain on the basis of previous studies of permafrost and thaw lakes at barrow alaska a series of simulation cases was conducted using different combinations of long term mean lake bottom temperature and lake depth the simulated results indicate that shallow thaw lakes are a significant heat source to permafrost and talik for a thaw lake with a long term mean lake bottom temperature of greater than 0 0 c a talik forms under the thaw lake the maximum talik thicknesses vertical distance from the ground surface to the permafrost surface are 28 0 43 0 and 53 2 m 3000 years after the formation of a shallow thaw lake with long term mean lake bottom temperatures of 1 0 2 0 and 3 0 c respectively talik development rate is very high in the first several years after a thaw lake formation and decreases gradually with time no talik forms below a thaw lake with a long term mean lake bottom temperature equal to or lower than 0 0 c but the temperature of permafrost below the thaw lake increases with time three thousand years after the formation of a thaw lake with a long term mean lake bottom temperature of greater than or equal to 2 0 c ground temperature increases of more than 0 5 c occur as far as 300 m from the lake shore and as deep as about 400 m below the ground surface it is concluded that variation of long term mean lake bottom temperature has a significant influence on permafrost thermal regime and talik development continued monitoring for thaw lake bottom temperature and ground temperature under shallow thaw lakes is needed to further improve the simulation

estimating late winter heat flow to the atmosphere from the lake dominated alaskan north slope the conductive heat flux through the snow cover f a is used as a proxy to examine the hypothesis that there is a significant heat flow from the alaskan north slope to the atmosphere because of the large number of lakes in the region f a is estimated from measurements of snow depth temperature and density on tundra grounded ice and floating ice in mid april 1997 at six lakes near barrow northwestern alaska the mean f a values from tundra grounded ice and floating ice are 1 5 5 4 and 18 6 w m 2 respectively a numerical model of the coupled snow ice water soil system is used to simulate f a and there is good agreement between the simulated and measured fluxes the flux from the tundra is low because the soils have a relatively low thermal conductivity and the active layer cools significantly after freezing completely the previous autumn the flux from the floating ice is high because the ice has a relatively high thermal conductivity and a body of relatively warm water remains below the growing ice at the end of winter the flux from the grounded ice is intermediate between that from the tundra and that from the floating ice and depends on the timing of the contact between the growing ice and the lake sediments and whether or not those sediments freeze completely using the estimated f a values combined with the areal fractions of tundra grounded ice and floating ice derived from synthetic aperture radar images area weighted f a values are calculated for six areas f a values for the ice vary between 9 8 and 13 8 w m 2 and those from the ice plus tundra vary between 3 9 and 5 3 w m 2 the f a values are similar to those observed in the sea ice covered regions of the south and north polar oceans in winter the north slope of alaska may thus make a significant contribution to the regional energy budget in winter

evolution of lakes and basins in northern alaska and discussion of the thaw lake cycle 1 we evaluated the development of lake basins on the central coastal plain of northern alaska on the basis of topographic profiles soil and ground ice surveys radiocarbon dating photogrammetric analysis and regional comparisons our analysis reveals that lake evolution is much more complex and less cyclic than theorized by previous investigations in the area we studied there was insufficient ground ice in the oldest terrain to form thaw lakes the aggradation of ice in the margins of drained lake basins was insufficient to heave the surface up to near original topographic conditions and the process occurs at too slow a rate for a thaw lake cycle to develop within the holocene accordingly we revised the conceptual model of lake and basin development to be consistent with the patterns and process we observed on the extensive sand sheets underlying most of the coastal plain developmental stages include 1 initial flooding of depressions to form primary lakes 2 lateral erosion with sorting and redistribution of sediments 3 lake drainage as the stream network expands 4 differential ice aggradation in silty centers and sandy margins 5 formation of secondary thaw lakes in the heaved centers of ice rich basins and infilling of ponds along the low margins and 6 basin stabilization

ice processes and surface ablation in a shallow thermokarst lake in the central qinghai tibetan plateau the qinghai tibetan plateau qtp is characterized by a cold climate and a large number of lakes the long ice season necessitates study of the widespread ice covers in the region an unprecedented multidisciplinary field campaign was conducted on lake ice processes in the central qtp during the period 2019 13 the study lake generally froze up in late october or early november and broke up in mid or late april with a maximum ice thickness of 50 70 cm the mass balances at both ice surface and bottom were measured continuously significant ice surface sublimation ablation was detected and accounted for up to 40 of the whole ice thickness over the ice season a simple heat transfer model was developed for the surface ice loss the calculated values were in good agreement with the observations they also indicated that atmospheric conditions including low air humidity and prevailing strong winds are the primary drivers of the ice surface sublimation

metal fractionation in oxic sediments of an estuary affected by acid mine drainage south western spain abstract fractionation of fe cu zn as cd and pb was studied in 17 surface sediment samples of the ria of huelva in all the cases total concentration of these elements was high especially for fe 11 2 zn 1519 ppm followed by cu 1413 ppm pb 716 ppm as 442 ppm and cd 3 26 ppm the enrichment factors of these metals follow this order cd cu zn pb as fe with respect to the regional background the highest concentrations associated with exchangeable or labile fractions are shown by zn 85 of total concentration followed by cd 76 12 fe 58 41 cu 40 80 pb 37 44 and as 33 88 the main sources of metal input are the tinto and odiel rivers which discharge acidic water ph

arsenic from gold mining in marine and stream sediments in baja california sur mexico the environmental impacts associated with arsenic as from historical mining areas may persist for many years we evaluated the influence of as in smelter and tailing wastes from a historic gold mine near san antonio in the south east of the baja california mexico on fluvial and marine sediments in the san juan de los planes basin and la ventana bay respectively arsenic levels in the smelter and in the surrounding tailing wastes ranged from 82 000 to 208 000 mg kg 1 and from 4220 to 92 000 mg kg 1 respectively the as concentrations in fluvial sediments were much lower as these derived from wastes that had been scattered and had been subject to weathering for some time as concentrations in surface sediments in the san antonio stream close to the smelter and further downstream ranged from 477 to 1100 mg kg 1 and from 64 to 613 mg kg 1 respectively as concentrations were between 0 05 and 9 mg kg 1 in surface shelf sediments from the coast adjacent to la ventana bay the concentration was highest in sediment collected close to the outlet of the main stream la bocana of the los planes basin the as concentrations in all the solid waste samples from near san antonio exceeded the effect range medium erm of the sediment quality guidelines 70 mg kg 1 overall 71 and 43 of the stream samples exceeded the effect range low erl 8 2 mg kg 1 and the erm respectively indicating potential risks for biota and humans

scenarios of tsunami amplitudes in the north eastern coast of sea of marmara generated by submarine mass failure in this paper the tsunamis resulting from a submarine mass failure such as slides and slumps triggered by earthquakes or other environmental effects which is settled at the bottom of the north eastern sea of marmara are examined in one sample region as the solution method one hybrid method is developed the main objective of this method is to combine an analytical solution presenting near field tsunami amplitudes above the submarine mass failure with a numerical solution indicating the tsunami amplitudes in the coastal regions for this purpose one common linear boundary between analytical and numerical solution domains is defined movements of submarine mass failures smf are modeled using one simple kinematics source model and the amplitudes of the tsunamis at the region that are closer to the landslide are computed by using the analytical method smf is modeled approximately from the bottom geometry and an average depth is used scenarios of smf are established depending on the velocities and thicknesses of the failure and near field tsunami amplitudes are obtained in the open sea during the source time after the source times the solutions are found in the numerical region using telemac 2d software system with the mentioned boundary above in this boundary the output of the analytical solutions is taken as the boundary conditions or the disturbances for the numerical method with these disturbances the numerical method is performed and the amplitudes are calculated in the coastal area the generation propagation and coastal amplifications of the tsunamis are illustrated at some certain points and regions both in the open sea and near the coast line the results have been visualized and discussed

arsenic content and groundwater geochemistry of the san antonio el triunfo carrizal and los planes aquifers in southernmost baja california mexico the san antonio el triunfo mining district located at a mountainous region 45 km south east of la paz baja california has been worked since the late 1700s mine waste material produced during 200 years of mineral extraction area poses a risk of local groundwater pollution and eventually regional pollution to the carrizal west basin and the los planes east basin aquifers there are different types of deposits in the mining area these are dominated by epithermal veins in which arsenopyrite is an important component carrillo and drever 1998a concluded that even though the amount of mine waste is relatively small in comparison to the large scale area significant as in groundwater derived from the mine waste piles is found locally in the groundwater this paper shows the results of geochemical analyses of groundwater samples from the san antonio el triunfo area and the carrizal and los planes aquifers during several years of monitoring 1993 1997 the highest values of total dissolved solids tds and as are in the mineralized area where the mining operations occurred 1500 ppm tds and 0 41 ppm as the lowest concentrations of tds and as are in general away from the mineralized area 500 ppm tds and 0 01 ppm as sulfate and bicarbonate alkalinity are in general high near the mineralized area and low away from it the arsenic concentrations vary seasonally especially after the heavy summer thunderstorms geochemical modeling minteqa2 and netpath and analysis of the regional geochemical evolution of the groundwater from the mining area towards the aquifer of los planes shows that the most likely hydrochemical processes include dilution precipitation of calcite and adsorption of as onto surfaces of iron oxyhydroxides ferrihydrite these processes act as natural controls to the extent and amount of as pollution in the carrizal and los planes aquifers

evaluation of tsunami amplitudes for the pacific coast of canada abstract maximum tsunami water levels and currents along the british columbia outer coast have been computed for waves originating from alaska chile the aleutian islands shumagin gap and kamchatka three computer models have been developed to generate and propagate a tsunami from each of these source regions in the pacific ocean to the continental shelf off canada s west coast and into 20 separate inlet systems the model predictions have been verified against water level measurements made at tide gauges after the march 28 1964 alaska earthquake simulated seabed motions giving rise to the alaskan and chilean tsunamis have been based on surveys of vertical displacements made after the great earthquakes of 1964 alaska and 1960 chile hypothetical bottom motions have been used for the shumagin gap and kamachatka simulations these simulations represent the largest tsunamigenic events to be expected from these areas maximum wave and current amplitudes have been tabulated for each simulated tsunami in 185 key locations along the british columbia coast on the north coast of british columbia the alaska tsunami generated the largest amplitudes in all other regions of the west coast the largest amplitudes were generated by the shumagin gap simulation wave amplitudes in excess of 9 m were predicted at several locations along the coast and current speeds of 3 to 4 m s were produced the most vulnerable regions are the outer coast of vancouver island the west coast of graham island and the central coast of the mainland some areas such as the north central coast are sheltered enough to limit expected maximum water levels to less than 3 m the computer models developed in this study are sufficiently general to be applicable to other tsunami affected regions on the globe

tundra lakes and permafrost richards island western arctic coast canada lakes of average size 33 ha occupy a quarter of the surface area of richards island northwest territories most of the lakes have a central pool deeper than the thickness of winter ice and many have prominent shallow littoral terraces the relatively warm lake bottoms cause considerable disturbance to the surrounding continuous permafrost water and lake bottom temperatures the configuration of permafrost and active layer thickness were measured at a tundra lake between 1992 and 1997 the lake is oval 1 6 km long 800 m wide and as deep as 13 m sandy terraces covered by less than 1 m of water extend over 100 m from the shore the terraces are underlain by permafrost which terminates almost vertically at their edge the annual mean temperature measured at lake bottom in the central pool ranged between 1 5 c and 4 8 c depending on depth and between 0 2 c and 5 c on the terraces due to differences in snow cover and proximity to the central pool in consequence the temperature of permafrost at 7 m depth in the terraces also varied from 2 c near shore to 5 c in mid terrace the active layer in the terraces was uniformly 1 4 m deep geothermal modelling of talik configuration indicates that there is no permafrost beneath the central pool of the lake the modelling indicates that under equilibrium conditions about one quarter of the lakes on richards island have taliks that penetrate permafrost and at least 10 15 of the island is underlain by talik short term climatic changes predicted for the region imply a small increase in summer lake water temperature and an extension of the open water season accompanied by thicker snow cover in winter following such changes with longer freeze up and warmer terrace temperatures in winter permafrost may not be sustainable in the lake terraces

rapid degradation of permafrost underneath waterbodies in tundra landscapes toward a representation of thermokarst in land surface models waterbodies such as lakes and ponds are abundant in vast arctic landscapes and strongly affect the thermal state of the surrounding permafrost in order to gain a better understanding of the impact of small and medium sized waterbodies on permafrost and the formation of thermokarst a land surface model was developed that can represent the vertical and lateral thermal interactions between waterbodies and permafrost the model was validated using temperature measurements from two typical waterbodies located within the lena river delta in northern siberia impact simulations were performed under current climate conditions as well as under a moderate and a strong climate warming scenario the performed simulations demonstrate that small waterbodies can rise the sediment surface temperature by more than 10 c and accelerate permafrost thaw by a factor of between 4 and 5 up to 70 of this additional heat flux into the ground was found to be dissipated into the surrounding permafrost by lateral ground heat flux in the case of small shallow and isolated waterbodies under moderate climate warming the lateral heat flux was found to reduce permafrost degradation underneath waterbodies by a factor of 2 under stronger climatic warming however the lateral heat flux was too small to prevent rapid permafrost degradation the lateral heat flux was also found to strongly impede the formation of thermokarst despite this stabilizing effect our simulations have demonstrated that underneath shallow waterbodies 1 m thermokarst initiation happens 30 to 40 years earlier than in simulations without preexisting waterbody

arsenic behaviour in gold ore mill tailings massif central france hydrogeochemical study and investigation of in situ redox signatures abstract historical au ore exploitation at the cheni mine in the massif central france generated 525 000 tonnes of finely ground mill tailings deposited in a heap that has spread with time into three settling basins the tailings which are rich in quartz 80 mica and clay minerals 10 of illite smectite kaolinite and chlorite feldspars 5 but poor in carbonates e h 700 mv to moderate ph and weakly reducing ph 7 6 e h 15 mv the waters are rich in so 4 and ca and have variable as 0 05 95 mg l 1 and fe concentrations 0 07 141 mg l 1 reduced as iii species predominate over as v species as iii as v up to 21 whereas oxidized forms of fe and s are favoured fe ii fe iii up to 0 5 and s iv s vi up to 1 thermodynamic calculations were performed with the phreeqc and eq3nr codes based on a revised as database to evaluate saturation indices si of the waters in relation to the main minerals and define which redox couples control the redox state of the system the important role of carbonates though only present in small amounts explains the acid buffering generated by the oxidation of sulphides for waters in the ph 7 7 5 range measured e h appears to fall between the calculated e h of the fe ii fe iii couple and that of the as iii as v couple illustrating redox disequilibrium

modeling of the february 1996 peruvian tsunami the february 1996 peruvian earthquake generated a larger tsunami than expected from its surface magnitude this discrepancy as well as the long rupture duration indicate that this event is a tsunami earthquake the associated tsunami was strong locally with runup heights of 1 to 5 meters along a coastline of 400 km it is shown that this tsunami can be modeled for a seismic moment of 2 1020 nm using a rigidity of 2 1010 n m the tsunami propagation is modeled solving long wave equations by a finite difference method the maximum run up heights in the region of chimbote can be simulated using a grid increment of 10 meters the propagation of this small tsunami across the pacific ocean is modeled taking into account frequency dispersion the only notable amplification occurred in the marquesas islands where wave heights of 2 meters were observed and are simulated

tsunami hazard in the marmara sea turkey a numerical approach to discuss active faulting and impact on the istanbul coastal areas abstract the westward propagation of the seismic ruptures along the north anatolian fault naf during the 20th century has increased the probability that the next rupture will be located offshore in the marmara sea in the prolongation of the 1999 izmit earthquake faulting historical tsunamis have been evidenced in the marmara sea e g those associated with the 1509 may 1766 strong earthquakes that broke submarine parts of the naf in the vicinity of istanbul and future submarine events are expected to produce tsunamis as well that could be triggered either by submarine coseismic displacements or by landsliding the assessment of their amplitude and extent of their effects is discussed in this paper through numerical modeling based on both earthquake and landsliding sources we use a finite difference method that yields the maximum water levels reached in the marmara sea and the effects run up values around the coasts of istanbul using a set of three nested bathymetric grids with a decreasing cell size to focus on istanbul first we consider probable earthquake sources along the northern branch of the emerged naf namely in the eastern cinarcik basin magnitude mw 7 2 in the western tekirdag and central basins magnitude mw 7 5 and along the whole branch magnitude mw 7 6 the impact obtained in istanbul is all the more important as a normal component in the eastern basin is present and maximum water levels can reach 2 m along the shoreline provoking locally significant inundations these results show that the historical tsunami observations around istanbul 1509 may 1766 provided they are directly due to earthquake sources imply a significant normal component in the eastern basin whatever the extent of the rupture westward conversely a source located in the western and or central basin does not provoke large waves in istanbul e g august 1766 most probably finally we test three landslide sources in the southern vicinity of istanbul and show that the damage is expected to be larger than in the case of earthquake sources for moderate to large volumes involved this kind of source in addition to the coseismic deformation could therefore be a good candidate to explain the historical waves in istanbul especially in 1509 where run up values as high as 6 m have been reported provided we are confident in the historical documents available

hydrostatic versus non hydrostatic modeling of tsunamis with implications for insular shelf and reef environments abstract dispersion is known to separate frequency components and reduce the amplitude of tsunami waves in the open ocean the present paper elucidates a reverse process in which the dispersed wave components from trans oceanic propagation of the 2011 tohoku tsunami regroup over the insular shelves and reefs of hawaii the non hydrostatic and hydrostatic modes of a nonlinear long wave model describe the pertinent processes with and without dispersion using the same system of two way nested grids for direct comparison both solutions have very similar amplitude spectra across the ocean and reproduce the dominant components of recorded surface elevations and currents in hawaii despite their markedly different offshore waveforms the hydrostatic solution shows early arrival of short period signals from nonlinear scattering around the hawaiian islands and faster attenuation of the amplitude due to their local source the short period trailing waves from dispersion more effectively excite shelf and reef oscillations giving rise to better agreement with both the amplitude and phase of the recorded data even with larger offshore wave amplitude a hydrostatic model trends to underestimate the surge elevation and current velocity at coastlines fronted by shallow reefs susceptible to resonance oscillations associated with edge waves