the effect of hydrogeological conditions on variability and dynamic of groundwater recharge in a carbonate aquifer at local scale summary groundwater recharge in fractured karstic aquifers is particularly difficult to quantify due to the rock mass s heterogeneity and complexity that include preferential flow paths along karst conduits the present study s major goals were to assess how the changes in lithology as well as the fractured karst systems influence the flow mechanism in the unsaturated zone and to define the spatial variation of the groundwater recharge at local scale the study area is located within the fractured carbonate western mountain aquifer yarkon taninim west of the city of jerusalem at the ein karem ek production well field field monitoring included groundwater level observations in nine locations in the study area during years 1990 2014 the measured groundwater level series were analyzed with the aid of one dimensional dual permeability numerical model of water flow in variably saturated fractured porous media which was calibrated and used to estimate groundwater recharge at nine locations the recharge values exhibit significant spatial and temporal variation with mean and standard deviation values of 216 and 113 mm year respectively based on simulations relationships were established between precipitation and groundwater recharge in each of the nine studied sites and compared with similar ones obtained in earlier regional studies simulations show that fast and slow flow paths conditions also influence annual cumulative groundwater recharge dynamic in areas where fast flow paths exist most of the groundwater recharge occurs during the rainy season 60 80 from the total recharge for the tested years while in locations with slow flow path conditions the recharge rate stays relatively constant with a close to linear pattern and continues during summer

paleotsunami research along the nankai trough and ryukyu trench subduction zones current achievements and future challenges abstract located near japan s most densely populated and industrially active region the nankai trough subduction zone has long been highlighted as a high risk area for damaging earthquakes and tsunamis in contrast less attention has been paid the adjacent ryukyu trench because historical and geological records are scarce in order to develop better quantitative estimates of the timing and size of the earthquakes and tsunamis generated along these subduction zones comprehensive studies using geological seismological and historical methods have been conducted since the 1990s studies of tsunami deposits in this region have contributed to our current understanding of the history of tsunamis over the last 6000 years following the 2011 t hoku earthquake and tsunami paleotsunami research has especially focused on guiding and enhancing tsunami disaster management and mitigation measures the last nine years have seen a rapid increase in paleotsunami data from the nankai trough and ryukyu trench coasts these recent studies reveal that there are significant differences in the size and recurrence pattern of earthquakes and tsunamis along these subduction zones for instance large earthquakes have repeatedly occurred along the nankai trough every 100 200 years on the other hand large earthquakes and tsunamis may not have occurred over the last few thousand years at the junction between these subduction zones there is also no evidence for the occurrence of large earthquakes along the northern and central ryukyu trench over this time period large earthquakes and tsunamis may have occurred every few hundred years at the southern end of the ryukyu trench nevertheless data on the occurrence of these earthquakes are still insufficient both in quantity and quality to estimate the maximum size or recurrence pattern

the dibdibba aquifer system at safwan zubair area southern iraq hydrogeology and environmental situation the objective of this research is to study the environment and hydrogeology of the dibdibba aquifer system in the safwan zubair area southern iraq in relation to the study area s geology and anthropogenic activities ten groundwater samples were collected from safwan zubair geochemical data aquachem and gis arcmap 10 1 were used as tools to identify natural and anthropogenic factors that affect geochemical data we analyzed water samples for major cations and anions polycyclic aromatic hydrocarbons pahs total uranium tu and heavy metals pb ni cr cd v zn as se cu fe mn as well as the metalloid b groundwater composition in the area of study is classified into six types ca mg cl ca mg na cl ca mg cl so4 ca mg na cl so4 ca na mg so4 cl and mg ca cl so4 the groundwater is influenced by natural factors particularly the concentrations of tu and major ions the concentrations of tu and major ions in some water samples exceed limits for drinking water however the average of all examined heavy metals except for fe and b was within the limits for drinking water as well as the concentrations of pahs the potential use of this groundwater for drinking and irrigation is discussed

a pseudo genetic stochastic model to generate karstic networks summary in this paper we present a methodology for the stochastic simulation of 3d karstic conduits accounting for conceptual knowledge about the speleogenesis processes and accounting for a wide variety of field measurements the methodology consists of four main steps first a 3d geological model of the region is built the second step consists in the stochastic modeling of the internal heterogeneity of the karst formations e g initial fracturation bedding planes inception horizons etc then a study of the regional hydrology hydrogeology is conducted to identify the potential inlets and outlets of the system the base levels and the possibility of having different phases of karstification the last step consists in generating the conduits in an iterative manner using a fast marching algorithm in most of these steps a probabilistic model can be used to represent the degree of knowledge available and the remaining uncertainty depending on the data at hand the conduits are assumed to follow minimum effort paths in a heterogeneous medium from sinkholes or dolines toward springs the search of the shortest path is performed using a fast marching algorithm this process can be iterative allowing to account for the presence of already simulated conduits and to produce a hierarchical network the final result is a stochastic ensemble of 3d karst reservoir models that are all constrained by the regional geology the local heterogeneities and the regional flow conditions these networks can then be used to simulate flow and transport several levels of uncertainty can be considered large scale geological structures local heterogeneity position of possible inlets and outlets phases of karstification compared to other techniques this method is fast to account for the main factors controlling the 3d geometry of the network and to allow conditioning from available field observations

stratigraphic evidence of historical and prehistoric tsunamis on the pacific coast of central japan implications for the variable recurrence of tsunamis in the nankai trough abstract to complement historical written records of tsunamis in the nankai trough and reconstruct prehistoric tsunami records we conducted a coring survey at a coastal lowland in mie prefecture central japan we found 10 sand layers deposited from about 4500 to 500 years ago the layers are interpreted as tsunami deposits because of the presence of abundant bioclasts of marine organisms and sedimentary structures such as alternating sub layers of sand and silt rip up clasts and upward fining structures all of which are common in modern tsunami deposits at the study site no substantial seawater inundations and sand depositions have been recorded even for the largest typhoons to ever hit the region there are historical accounts of earthquake and tsunami damage along the nankai trough in 1498 1361 1096 887 and 684 ce estimated ages of the youngest three sand layers overlap well with tsunamis in 1498 1096 and 684 ce our results support the hypothesis suggested by archaeological studies that the 684 ce rupture extended farther eastward than the historical record indicates or that another tsunami occurred at some time close to 684 ce we did not find any sand layers that were definitely correlated with the tsunamis of 1361 and 887 ce which are thought to have occurred by multi segment ruptures of the nankai trough that includes the segment directly offshore from the study site if the sand layers found at the study site were deposited by the tsunamis of 1498 1096 and 684 ce and if the tsunamis of 1361 and 887 ce did not inundate the study site the tsunami recurrence interval during the relevant time period was about 400 years this finding does not support the widely believed hypothesis that earthquakes and tsunamis occur at regular intervals of approximately 100 years in this area in addition similar to the historical tsunamis intervals of geologically recorded prehistoric tsunamis at the study site vary from about 100 to 600 years the hypothesis of variable recurrence of earthquakes and tsunamis along the nankai trough should be tested by future geological and historical studies in unbiased way

tsunami deposits refine great earthquake rupture extent and recurrence over the past 1300 years along the nankai and tokai fault segments of the nankai trough japan abstract study of prehistoric to medieval age tsunami deposits along a riverbank site near the eastern nankai trough central japan show that not only did tokai earthquakes occur with a higher frequency than previously thought but that contemporaneous ruptures of the tokai and nankai fault segments were also more common the site revealed a 1 km long coast normal cross section of the strand plain and exposed four sandy tsunami deposits each of which indicates inundation over 2 km inland of the coast radiocarbon dating of previously studied and newly discovered deposits in the region indicates a shorter recurrence time for tokai earthquakes and clarifies their linkage with nankai earthquakes we attribute the younger two tsunami deposits to the 1498 and 1096 ce tokai earthquakes the older two deposits confirm the occurrence of the tokai earthquakes in 887 ce and in the latest 7th century these events are not reliably recorded in historical documents in the tokai region but were noted in the nankai area the 887 ce earthquake likely represents a full length rupture of the tokai and nankai segments as was the case for the 1707 ce earthquake integrated with the previous studies these new results show that nine tokai earthquakes occurred over the last 1300 years the oldest in the latest 7th century and in 887 1096 1361 1498 1614 1707 1854 and 1944 ce recalculated recurrence intervals range from 90 to 265 years except for the 1498 meio tokai earthquake the tokai earthquakes occurred simultaneously with nankai earthquakes

geodetic imaging of plate motions slip rates and partitioning of deformation in japan 1 interseismic deformation in japan results from the combined effects of tectonic processes including rotation of crustal blocks and the earthquake cycle process of elastic strain accumulation about upper plate faults and subduction zone interfaces we use spherical linear block theory constrained by geodetic observations from densely spaced global positioning system gps stations to estimate plate motions fault slip rates and spatially variable interplate coupling on the japan kuril sagami and nankai subduction zones the reference model developed in this paper consists of 20 blocks produces a mean residual velocity magnitude of 1 84 mm yr at 950 stations and accounts for 96 of the observed interseismic deformation signal we estimate fault slip rates in excess of 15 mm yr along the niigata kobe tectonic zone and itoigawa shizuoka tectonic line through central japan confirming their hypothesized roles as major tectonic boundaries oblique convergence across the nankai trough is partitioned with 3 4 of the 30 mm yr of trench parallel motion accommodated by strike slip motion on the subduction interface and the remaining 1 4 accommodated by right lateral slip on the median tectonic line in contrast our models suggest negligible slip partitioning in eastern hokkaido where oblique slip on the japan kuril subduction interface accommodates all of the trench parallel component of relative plate motion inferred spatial variations in the rake and magnitude of slip deficit on subduction zone interfaces reflect the influences of megathrust geometry and earthquake cycle processes such as enhanced elastic strain accumulation about seismic asperities and coseismic sense fault motion indicative of silent slip events or afterslip following large earthquakes

groundwater dynamics in fossil fractured carbonate aquifers in eastern arabian peninsula a preliminary investigation abstract eastern arabian peninsula represents the main natural groundwater discharge area of the arabian platform fossil aquifer system in such settings connections between aquifers could strongly affect the flow dynamics water quality and availability as well as karst formation and landscape evolution geological structures such as folds and faults are central to aquifer connectivity yet their role on groundwater flow is poorly understood herein we perform mapping of exposed and buried structural features in the qatar peninsula using landsat sentinel 2 and alos palsar scenes correlated with field gpr and isotopic data to assess their role in aquifer connections and groundwater dynamics our results suggest that ene wsw oriented fold related faults act as vertical conduits along which artesian upward leakages from the deep aruma aquifer take place into the shallower main aquifer unit i e umm er radhuma and rus in southern qatar peninsula on the other hand downward leakage from the freshwater lens in the dammam aquifer take place in northern qatar peninsula the deep brackish and gaseous rich waters ascending along faults in south qatar peninsula in addition to degrading the water quality in the main aquifer unit enhance dissolution of carbonates and evaporites leading to strong karstification that produces abundant collapse features our findings suggest that structure controls can add significant complexity to recharge mechanisms and groundwater dynamics in fossil aquifers future large scale radar subsurface mapping will be essential to resolve the variability of the water heads in such areas and its correlation to structural discontinuities

segmentation and supercycles a catalog of earthquake rupture patterns from the sumatran sunda megathrust and other well studied faults worldwide abstract after more than 100 years of earthquake research earthquake forecasting which relies on knowledge of past fault rupture patterns has become the foundation for societal defense against seismic natural disasters a concept that has come into focus more recently is that rupture segmentation and cyclicity can be complex and that a characteristic earthquake model is too simple to adequately describe much of fault behavior nevertheless recognizable patterns in earthquake recurrence emerge from long high resolution spatially distributed chronologies researchers now seek to discover the maximum minimum and typical rupture areas the distribution variability and spatial applicability of recurrence intervals and patterns of earthquake clustering in space and time the term supercycle has been used to describe repeating longer periods of elastic strain accumulation and release that involve multiple fault ruptures however this term has become very broadly applied lumping together several distinct phenomena that likely have disparate underlying causes we divide earthquake cycle behavior into four major classes that have different implications for seismic hazard and fault mechanics 1 quasi periodic similar ruptures 2 clustered similar ruptures 3 clustered complementary ruptures rupture cascades and 4 superimposed cycles segmentation is likewise an ambiguous term we identify master segments and asperities as defined by barriers to fault rupture these barriers may be persistent rarely or never traversed frequent occasionally traversed or ephemeral changing location from cycle to cycle we compile a catalog of the historical and paleoseismic evidence that currently exists for each of these types of behavior on major well studied faults worldwide due to the unique level of paleoseismic and paleogeodetic detail provided by the coral microatoll technique the sumatran sunda megathrust provides one of the most complete records over multiple earthquake rupture cycles long historical records of earthquakes along the south american and japanese subduction zones are also vital contributors to our catalog along with additional data compiled from subduction zones in cascadia alaska and middle america as well as the north anatolian and dead sea strike slip faults in the middle east we find that persistent and frequent barriers rupture cascades superimposed cycles and quasi periodic similar ruptures are common features of most major faults clustered similar ruptures do not appear to be common but broad overlap zones between neighboring segments do occur barrier regions accommodate slip through reduced interseismic coupling slow slip events and or smaller more localized ruptures and are frequently associated with structural features such as subducting seafloor relief or fault trace discontinuities this catalog of observations provides a basis for exploring and modeling root causes of rupture segmentation and cycle behavior we expect that researchers will recognize similar behavior styles on other major faults around the world

conceptual hydrogeological model of flow and transport of dissolved organic carbon in a small jura karst system summary this paper aims at characterizing infiltration and solute transport processes in a karst system during flood events in order to build a conceptual model of hydrogeological functioning the study site is the small karst system of fertans in the french jura soil cover rock matrix and a small spring were monitored to measure hydrological and hydrochemical parameters and particularly a continuous dissolved organic carbon doc signal which is a relevant environmental tracer of fast infiltration we used two combined approaches first from hydrodynamic and hydrochemical data we identified the system structure consistent with a dual porosity scheme and characterized the main processes occurring during flood events second on the basis of this scheme we built a new conceptual hydrogeological model coupled with doc transport to numerically validate the hydrological functioning this modelling approach is based on a rainfall discharge model to simulate spring flow solute transport is modelled using mixing equations including an empirical retardation factor as well as a first order solute decay the model was calibrated and validated on a set of nineteen flood events showing its performances in simulating spring hydrographs and delayed doc signals during flood events with various rainfall intensities we showed that the recharge area of the karst system varied largely with low and high groundwater periods which was attributed to the state of hydraulic connectivity in the unsaturated zone the soil cover appeared to play an important role of mixing and transfer for the recharge water the model simulated the contributions of pre event and event waters during flood events and allowed a better quantification of the available resource it showed in particular that total discharge of some flood events during low water periods is mainly composed of pre event water via piston flow type processes finally this study shows that the mixing model can simulate solute transport correctly taking into account degradation and retardation processes it highlights the need for a quantitative approach on hydrochemical studies of karst systems in order to understand them better

relationship between the maximum extent of tsunami sand and the inundation limit of the 2011 tohoku oki tsunami on the sendai plain japan abstract this paper focuses on the relationship between the maximum extent of sandy tsunami deposits and inundation distance of the 2011 tohoku oki tsunami inundation limits of the tohoku oki tsunami were assessed over seven shore normal transects along the sendai coastal plain inundation distances were found to range from 0 6 to 4 0 km at the maximum extent of the tsunami deposit the sand unit ranged in thicknesses from 0 1 to 4 0 cm the maximum limit of the 0 5 cm thick sand layer extended to over 90 of the inundation distance where the inundation distance was less than 2 5 km this observation is consistent with previous studies that examined characteristics of recent tsunami events that had inundation distances of at least 2 km the maximum limit of the 0 5 cm thick sand layer extended to 3 km 57 76 of the inundation distance where the inundation distance was more than 2 5 km our results are important for estimating paleo tsunami inundation distances based on the landward extent of sand deposits and valuable for the assessment of future tsunami risks in other coastal areas in the world which have been devastated by huge tsunamis in the past

remote sensing and gis techniques for reconstructing arabian palaeohydrology and identifying archaeological sites freshwater availability is critical for human survival and in the saharo arabian desert belt repeated fluctuations between aridity and humidity over the quaternary mean the distribution of freshwater was likely a primary control upon routes and opportunities for hominin dispersals however our knowledge of the spatio temporal distribution of palaeohydrological resources within arabia during mid late pleistocene episodes of climatic amelioration remains limited in this paper we outline a combined method for remotely mapping the location of palaeodrainage and palaeolakes in currently arid regions that were formerly subject to more humid conditions we demonstrate the potential of this approach by mapping palaeochannels across the whole arabian peninsula and palaeolakes and marshes for select regions covering c 10 of its surface our palaeodrainage mapping is based upon quantitative thresholding of hydrosheds data which applies flow routing to digital elevation model dem data while our palaeolake mapping uses an innovative method where spectral classification of landsat thematic mapper tm imagery is used to detect palaeolake deposits within endorheic closed basins before modelling maximum lake extents by flooding the basin to the level of the elevation of the highest detected deposit field survey in the nefud desert and the dawadmi and shuwaymis regions of saudi arabia indicates accuracies of 86 for palaeodrainage mapping and 96 for identifying former palaeolake basins 73 accuracy of classification of individual deposits the palaeolake mapping method has also demonstrated potential for identifying surface and stratified archaeological site locations with 76 of the surveyed palaeolake basins containing archaeological material including stratified palaeolithic archaeology initial examination of palaeodrainage in relation to archaeological sites indicates a relationship between mapped features and previously recorded palaeolithic sites an example of the application of these data for period specific regional palaeohydrological and archaeological reconstructions is presented for a region of northern saudi arabia covering the southern nefud desert and adjacent lava fields

monthly karstic spring flow forecasting using a sequential gaussian simulation technique analyzing groundwater hydrologic equations related to karstic aquifers and spring hydrograph simulation have become the focus of many researches having double or triple porosity structure mixed flow nature and varying conduit permeability have made these formations become complex heterogenic systems with great temporal and spatial hydrodynamic variability in this paper a conditional sequential gaussian simulation sgs is used to simulate monthly flow data of five karstic springs with different hydrogeological properties located in zagros mountain chain in western iran to evaluate the performance of the sgs algorithm the results are compared with those of an autoregressive integrated moving average arima model the results demonstrate the efficiency of the sgs model in simulation of monthly flows compared to the arima model they also show the suitability of this model for handling uncertainty associated with karstic spring flows through generation of several equally probable stochastic realizations

laboratory investigations of compatibility of the kuwait group aquifer kuwait with possible injection waters a laboratory investigation of the compatibility of the kuwait group aquifer of kuwait with desalinated seawater and reverse osmosis processed treated wastewater was carried out in anticipation of the artificial recharge of the aquifer in future even with the use of wax coating and freezing with liquid nitrogen no core plugs could be extracted from the unconsolidated sections and only the consolidated to semi consolidated sections could be studied the aquifer consists of silty and gravelly sand and is often highly calcareous the clay minerals present in the aquifer mostly belong to the montmorillonite and illite groups with some palygorskite mercury injection porosimetry experiments on core plugs from the more cemented parts of the aquifer suggest that to avoid significant clogging from suspended solids particles down to a diameter of 8 m should be filtered out of the injection water core flow experiments suggest that for the samples examined loss of permeability due to clay swelling is not very important the blocking of pore throats by moving fines may be a more serious problem during injection the geochemical simulation indicates that the possibility of scale formation when the injection waters come in contact with the kuwait group formation water is remote rather there is a possibility of dissolution of carbonate minerals in the aquifer in contact with the injection waters

analysis of well hydrographs in a karst aquifer estimates of specific yields and continuum transmissivities abstract hydrograph analysis techniques have been well developed for hydrographs obtained from streams and springs where data are cast in terms of total discharge the data obtained from well hydrographs provide water level versus time hence a method of hydrograph analysis is required for situations in which only water level data are available it is assumed here that three segments on a recession curve from wells in a karst aquifer represent drainage from three types of storage conduit c fracture f and matrix m hydrographs from several wells in a karst aquifer are used to estimate the specific yields sy associated with each portion of the aquifer c f m as well as continuum transmissivities t data from three short injection tests at one well indicate continuum t at this well bore is approximately 5 m2 day 1 and tests at numerous other wells in the aquifer yield results between 1 and 7 m2 day 1 the t estimated with well hydrographs from two storms indicates a t of 9 8 m2 day 1 well developed conduit systems in which water levels in wells show a flashy response typically show sys of 1 10 4 1 10 3 and 3 10 3 for c f and m respectively less well developed conduit areas show more nearly equal sys 8 6 10 4 1 3 10 3 3 10 3 areas with no evidence for the presence of conduits have only one or in some cases two slopes on the recession curve in these cases water level responses are slow recession curves with a single slope represent drainage from only the lower t matrix those with two slopes have an additional more rapid response segment on the recession curve which represents drainage from the higher t lower sy fractures in the system

challenges of anticipating the 2011 tohoku earthquake and tsunami using coastal geology 1 can the magnitude of a giant earthquake be estimated from paleoseismological data alone attempts to estimate the size of the jogan earthquake of ad 869 whose tsunami affected much of the same coast as the 2011 tohoku tsunami offers an excellent opportunity to address this question which is fundamental to assessing earthquake and tsunami hazards at subduction zones between 2004 and 2010 examining stratigraphy at 399 locations beneath paddy fields along 180 km of coast mainly south of sendai we learned that a tsunami deposit associated with the ad 869 jogan earthquake had run inland at least 1 5 km across multiple coastal lowlands and that one of the lowlands had subsided during the jogan earthquake and an earlier earthquake as well radiocarbon ages just below above sand deposits left by the pre jogan tsunamis suggested recurrence intervals in the range of 500 to 800 years modeling inundation and subsidence we estimated size of the jogan earthquake as moment magnitude 8 4 or larger and a fault rupture area 200 km long we did not consider a longer rupture like the one in 2011 because coastal landform and absence of a volcanic ash layer make any jogan layer difficult to identify along the sanriku coast still sendai tsunami geology might have reduced casualties by improving evacuation maps and informing public awareness campaigns

vertical tectonic crustal movements along the japanese coastlines inferred from late quaternary and recent relative sea level changes abstract observed relative sea level rsl changes during the past 130 kyr make it possible to evaluate the vertical crustal movement due to several tectonic processes such as the subduction of oceanic plates here we infer average rates of tectonic crustal movement along the japanese coastlines on three typical timescales of 50 yr 6 kyr and 125 kyr based on tide gauge and holocene rsl observations and the altitudes of marine terraces formed at the last interglacial lig phase at 125 ka the rates on a timescale of 50 yr are derived from tide gauge data thermosteric sea level changes due to thermal expansion of the oceans and predictions due to the glacio hydro isostatic adjustment gia for the last deglaciation and also recent melting of the mountain glaciers and greenland and antarctic ice sheets those for 6 kyr and 125 kyr are based on the rsl observations and the predictions by gia modelling considering uncertainties for temporal changes in eustatic sea level for the mid to late holocene and lig phase the inferred rates for 50 yr are significantly different from those for 125 kyr in most sites particularly for sites along the coastline from eastern hokkaido to northeastern japan shikoku and south kyushu facing the pacific ocean in these regions the rates for 125 kyr and 50 yr are positive uplift and negative subsidence respectively also the observed rsl changes at 6 ka are consistent with the inferred rsl changes using the rates for 125 kyr and gia predictions in many sites but inconsistent with those for 50 yr in most sites except for a few sites these results suggest that the rates on a timescale of 50 yr are not representative of the tectonic crustal movements for timescales longer than 6 kyr in most sites along the japanese coastlines however the inferred rates on these timescales may be useful in discussing the recurrence of megathrust earthquake with its interval of 1 kyr such as the 2011 earthquake off the pacific coast of tohoku

geochemistry of sediments of the al batin alluvial fan southern iraq the al batin alluvial fan covers a broad area of southern iraq it was the main battlefield of two devastating wars in 1991 and 2003 during which huge amounts of depleted uranium du were used this study aims to assess the geochemistry of this fan sediment including the potential effects of the du used sixty three samples were collected from sediments including three samples from sediments under tanks attacked by du ammunition major elements were measured by xrf fusion bead method whereas icp ms was used to measure the trace elements the results suggest that the most dominant major minerals are in the order of quartz secondary gypsum calcite feldspar clay minerals iron oxide and show abnormal concentrations of sr cr ni and v this study also determined an area with high concentration of u in the north east part of the fan statistical analysis and spatial distribution of important elements suggests that two major factors affect mineral formation the first factor reflects the influence of minerals in the source area of the sediments arabian shield quartz carbonate clay minerals feldspars as well as iron oxides and elevated concentrations of v ni and cr the second factor points at authigenic formation of secondary gypsum and celestite and elevated u concentration under the control of a hot arid climate and the specific groundwater situation however the origin of the sediments is geogenic while the anthropogenic impact seems to be minor spatial distribution of u and the 235 238u ratio did not show any peaks in the places where tanks have been destroyed this is contrary to media speculations and some scientific reports about the permanent risks of du in the area which creates public concern about the potential risk of living in this area

calcrete and near surface geology of kuwait city and suburbs kuwait arabian gulf abstract near surface accumulation of pedogenic carbonate calcrete is a common and characteristic feature of the landscape of kuwait city and its suburbs the principal host material for these calcretes is a thick sequence of unconsolidated quartzose sand a typical fully developed soil profile can be divided into five zones in descending order these are 1 a top calcareous aeolian soil 2 a zone of friable sand with powdery or tightly cemented calcrete lumps nodules 3 a massive calcrete zone 4 a mottled calcrete zone and 5 unaltered parent material episodic formation of calcrete is indicated by the occurrence of multiple profiles in which zones are repeated calcrete ooids and pseudo ooids of accretionary origin are characteristic of the upper calcrete zone the carbonate fraction in the upper calcrete zone consists dominantly of low mg calcite with minor amounts of dolomite replacement was a major process in formation of the massive calcrete and the dominant cementing material is largely low mg calcite and or microcrystalline dolomite aeolian dust is considered to be the major source of ions for calcrete formation in kuwait city and suburbs an earlier introduced model is applied to explain the mechanisms of formation and precipitation of low mg calcite and dolomite the calcrete thickness in the study area is explained by episodic deposition of fluviatile sand and calcrete formation during the oligocene through lower miocene period

analytical 1d dual porosity equivalent solutions to 3d discrete single continuum models application to karstic spring hydrograph modelling abstract one dimensional analytical porosity weighted solutions of the dual porosity model are derived providing insights on how to relate exchange and storage coefficients to the volumetric density of the high permeability medium it is shown that porosity weighted storage and exchange coefficients are needed when handling highly heterogeneous systems such as karstic aquifers using equivalent dual porosity models the sensitivity of these coefficients is illustrated by means of numerical experiments with theoretical karst systems the presented 1d dual porosity analytical model is used to reproduce the hydraulic responses of reference 3d karst aquifers modelled by a discrete single continuum approach under various stress conditions simulation results show the relations between the dual porosity model coefficients and the structural features of the discrete single continuum model the calibration of the equivalent 1d analytical dual porosity model on reference hydraulic responses confirms the dependence of the exchange coefficient with the karstic network density the use of the analytical model could also point out some fundamental structural properties of the karstic network that rule the shape of the hydraulic responses such as density and connectivity

an overview of the surface and near surface geology geomorphology and natural resources of kuwait abstract the surface and near surface geology geomorphology and natural resources of kuwait have been reviewed based on the published work the stratigraphy and structure of the near surface sediments of kuwait have been mainly controlled by the tertiary tectonic activity of the arabian shield the shield started separating from the african mainland by the close of the eocene and drifted northeastward towards the asian plate giving rise to the folding and thrusting of the zagros mountains of iran the tectonic activity superimposed a northwest southeast trend over an earlier north south structural trend and gave rise to parallel ridges and valleys trending northwest southeast through differential erosion it has been possible to identify 15 geomorphic zones and 11 morphostructures from analysis of the surface features of kuwait seven of these morphostructures can be attributed to tectonic processes and two to fluvial processes it has not been possible however to explain satisfactorily the origin of the jal az zor escarpment or the ad dalmaniyah cliff the whole of kuwait can be divided into seven drainage zones of these the internal drainage systems of the ar raudhatain umm al aish drainage system and the ad dibdibba drainage system are hydrogeologically most important the clastic deposits of kuwait group sediments often affected by low temperature carbonate calcite and dolomite and sulfate gypsum precipitation form the surface rock of kuwait these are covered by recent aeolian and residual deposits playa deposits in the enclosed basins and near the coast oolitic sediments beach sands and sabkha deposits the surface and near surface deposits of kuwait contain important reserves of construction sand and gravel as well as the only naturally occurring freshwater reserves of the country an understanding of the nature of these surface deposits is required for the management of environmental issues like sand encroachment land use planning and soil and groundwater pollution

inflow and outflow facies from the 1993 tsunami in southwest hokkaido abstract we describe in detail the sedimentary facies provenance and grain size distributions of the 1993 tsunami deposits in the lower reaches of usubetsu river only two lithofacies were recognized a gravel lobe facies glf and a sand sheet facies ssf the gravel lobe facies was deposited rapidly by a hydraulic jump in contrast the sand sheet facies which contains both current ripples and dunes was deposited by a traction current under subcritical flow conditions we identified four stratigraphic units unit 1 unit 2 unit 3 and unit 4 in ascending order we interpreted units 1 and 2 as having been deposited by the inflow and outflow events of the first run up and units 3 and 4 by the inflow and outflow events of the second run up respectively units 3 and 4 were more widely distributed and coarser grained than units 1 and 2 because the second run up was larger than the first run up furthermore unit 4 was more widely distributed than unit 3 because the outflow eroded the inflow deposits grain size distributions of the inflow and outflow deposits were clearly different unit 4 deposits had a peak at 2 5 phi p 1 population in contrast unit 3 deposits had a bimodal distribution with peaks at 0 5 1 5 phi p 2 population and at 2 5 phi p 1 population a comparison of the tsunami deposits with other sedimentary deposits near the study area showed that the tsunami deposits were mainly derived from the seabed at depths below 5 5 m in the offshore area where the marine sands are about 2 2 5 phi in size and thus are the source of the p 1 population the p 2 population is derived from coarse 0 5 2 phi fluvial materials eroded during the tsunami run up according to our calculations benthic foraminiferal tests were entrained from the comparatively deep seabed at depths up to 100 m during the tsunami run up and included in the tsunami deposits

historical nankai suruga megathrust earthquakes recorded by tsunami and terrestrial mass movement deposits on the shirasuka coastal lowlands shizuoka prefecture japan geological investigations of coastal sediment sequences play a key role in verifying earthquake and tsunami characteristics inferred from historical records in this paper we present a multi proxy investigation of a coastal lowland site facing the nankai suruga megathrust and appraise evidence for tsunamis and earthquake triggered terrestrial mass movements occurring over the last 800 years combining a high resolution chronology with x ray computed tomography and analyses of particle size diatoms pollen non pollen palynomorphs and aerial photographs we present the most compelling geological evidence of the 1361 ce koan also known as shohei tsunami reported to date from any site along the megathrust this finding is consistent with either of two recent hypotheses a single larger rupture of both the nankai and tnankai regions or two smaller ruptures separated by a few days enhancing the site chronology using bayesian age modelling we verify evidence for inundation during the 1498 ce mei tsunami while previous investigations identified evidence for historically recorded tsunamis in 1605 1707 and 1854 ce and a storm surge in 1680 or 1699 ce we encountered a thick sand layer rather than discrete extreme wave deposits in this interval the overprinting of evidence highlights the potential for geological records to underestimate the frequency of these events a terrestrial mass movement also deposited a sand layer at the site radionuclide dating and aerial photographs provide independent confirmation that this may have been triggered by intense shaking in 1944 ce during the most recent great nankai suruga megathrust earthquake

flow behavior in a dual fracture network a model that incorporates a pseudo random process controlled by mechanical rules of fracturing is used to generate 3d orthogonal joint networks in tabular stratified aquifers the results presented here assume that two sets of fractures each with different conductivities coexist this is the case in many aquifers or petroleum reservoirs that contain sets of fractures with distinct hydraulic properties related to each direction of fracturing constant rate pump tests from partially penetrating wells are simulated in synthetic networks the transient head response is analyzed using the type curve approach and plots as a function of time of pressure propagation in the synthetic network are shown the hydrodynamic response can result in a pressure transient that is similar to a dual porosity behavior even though such an assumption was not made a priori we show in this paper that this dual porosity like flow behavior is in fact related to the major role of the network connectivity especially around the well and to the aperture contrast between the different families of fractures that especially affects the earlier hydrodynamic response flow characteristics that may be interpreted as a dual porosity flow behavior are thus related to a lateral heterogeneity large fracture or small fault accordingly when a dual porosity model matches well test data the resulting reservoir parameters can be erroneous because of the model assumptions basis that are not necessarily verified finally it is shown both on simulated data and well test data that such confusion in the interpretation of the flow behavior can easily occur well test data from a single well must therefore be used cautiously to assess the flow properties of fractured reservoirs with lateral heterogeneities such as large fractures or small faults

shorter intervals between great earthquakes near sendai scour ponds and a sand layer attributable to a d 1454 overwash a sparsely documented tsunami in 1454 may subdivide the recurrence interval between the 869 and 2011 tsunamis near sendai as judged from geomorphic stratigraphic and archival evidence pond filled breaches cut across beach ridges on century old topographic maps the basal pond deposit in one of these breaches postdates 1454 stratigraphy on sendai plain includes a sand sheet that contains marine and brackish diatoms radiocarbon ages suggest that the sheet dates to 1406 1615 2 and written records for this interval in tohoku mention a tsunami in 1454 the inferred inundation extended 1 0 2 5 km inland from an approximate medieval shoreline simulated tsunamis that best account for the sand sheet require a thrust earthquake of moment magnitude 8 4 or larger if the sand sheet represents the 1454 tsunami the two most recent intervals between great thrust earthquakes in sendai region spanned 585 and 557 years

erosion deposition and landscape change on the sendai coastal plain japan resulting from the march 11 2011 tohoku oki tsunami case studies of recent tsunami impacts have proven to be extremely useful in understanding the geologic processes involved during inundation and return flow and refining the criteria used to identify paleotsunami deposits in the geologic record here we report on erosion deposition and associated landscape change resulting from the march 11 2011 tohoku oki tsunami along a nearly 4 5 km shore normal transect on the coastal plain near sendai japan the study area on the broad low relief prograding coastal sendai plain comprised a sand beach backed by 3 m high sand dunes and a forest a wetland the teizan canal agricultural rice fields buildings and roads field observations focused on measurements of tsunami flow characteristics height and direction mapping of erosion features and assessing sediment deposition based on shallow trenches at 50 100 m spacing recorded tsunami inundation heights reached up to about 11 m above mean sea level within the first 500 m from the shoreline and then ranged between 3 and 5 m for the next 2 km gradually decreasing to about 3 m close to the inundation limit the tsunami deposit generally thinned landward from an average maximum 30 cm thick sand deposit in the coastal forest to a thin mud drape several mm thick near the inundation limit a discontinuous sand dominated sheet was prevalent to about 2800 m from the shoreline where mud content then gradually increased further landward eventually resulting in a mud dominated deposit ranging from 3 5 cm to a few mm thickness the overall thinning and fining of the deposit was often interrupted by localized features that led to complex sedimentological relationships over short distances satellite imagery taken on 14 march 2011 3 days after the tohoku oki tsunami shows prominent foreshore incisions with 100 s meters spacing alongshore a foredune ridge that underwent severe erosion and development of a prominent shore parallel elongated scour depression our field survey in early may 2011 revealed that the foreshore recovered quickly with rapid post tsunami sediment deposition from incident waves whereas the dune ridge complex had undergone only minor re working from eolian processes

comparative morphosedimentary framework of small subtropical islands offshore kuwait abstract five small islands offshore of the state of kuwait in the northern arabian gulf miskan awhah kubbar qaruh and umm al maradem occur in differing structural settings and have evolved in a dynamic environment of shifting fluvial depocenters fluctuating holocene sea level and variable tidal conditions as a first step in reconstructing the origin and evolution of the islands bathymetric charts historical photographs topographic profiles and sediment samples were used to investigate their geomorphology and sedimentary environments the subaerial portion of the islands varies in area from 0 04 to 0 57 km2 the plan shape ellipticity ranges from nearly circular 0 10 to oval shaped 0 54 the northern two islands miskan and awhah experience mesotidal conditions and are situated on a shallow platform

ambiguous correlation of precisely dated coral detritus with the tsunamis of 1861 and 1907 at simeulue island aceh province indonesia precise u th dates from coral detritus in two pre 2004 tsunami deposits on simeulue island in aceh province allow us to correlate the deposits with historically documented tsunamis in the recent few centuries but because of potential discordance between the death dates of the corals and deposition of the sand layers ambiguity in this correlation remains pits at coastal lowland sites exposed sand layers beneath the 2004 tsunami deposit at busung and naibos on southern simeulue island the layers share sedimentological characteristics with the deposit of the 2004 tsunami and are interpreted as pre 2004 tsunami deposits historical accounts document earthquakes and tsunamis in 1907 and 1861 and suggest that the 1907 tsunami was larger locally than any others historically nonetheless u th analyses of coral boulders in the younger of two pre 2004 deposits at busung and in the lone deposit at naibos yielded dates of death that overlap with 1861 but there were no tsunami layers that could be directly dated to 1907 the younger pre 2004 sand deposit can be attributed to both the 1861 and 1907 events if the dated corals were killed by uplift in 1861 and subsequently entrained and deposited by the 1907 tsunami a piece of coral in the older of the two pre 2004 sand layers at busung dated to around ad 1783 and was deposited by an unknown tsunami that occurred after ad 1783 or possibly by the 1861 tsunami the nearly equatorial latitude of the study sites minimizes potential for geological confusion between tsunami and storm our results show the difficulty in matching known events and geological records when using limiting maximum ages from allochthonous fossils even with high precision radiometric dates

paleoclimatic investigations using isotopic signatures of the late pleistocene holocene groundwater of the stratified aquifers in kuwait abstract the study attempts to determine paleo recharge sources for two major aquifer units of kuwait namely kuwait group aquifer kga and dammam formation dfm were collected and analyzed for major ions and isotopes the obtained results of 14c ages indicated that the groundwater samples ranged from 31 9 ky to 3 9 ky in dfm and 23 3 ky to 0 8 ky in kga the variations in 18o signatures with respect to age reflected that there were two major sources of rainwater such as enriched southern indian ocean monsoon and the depleted northwesterly mediterranean vapor source the samples found to show variations during the three marine isotopic stages mis 1 3 heinrich events bolling allerod and dryas time periods in both aquifers a shift in the intertropical convergence zone itcz was witnessed in the groundwater of both aquifers from 7 8 ky to 4 9 ky the variation in the holocene climate is mainly due to the influence of tropospheric easterly jet governed by the swing in itcz as a result of holocene volcanism the mean 18o values of dfm samples 3 81 reflect depletion than kga samples 2 31 and the d excess values were 0 95 and 2 05 respectively thus it could be inferred that the dfm was predominantly recharged during late pleistocene period and it was in a relatively cooler climate than recharge environment of kga the study infers that kga was recharged between 26on and 26 8on latitudes and that of the dfm was noted to be recharged south west of kuwait in two different patches between 25 8on and 26 2on and 26 7on 27 4on latitudes during late pleistocene the kga was concluded to be recharged between 25 5on and 27 5on latitudes south of kuwait during holocene

historical tsunamis and storms recorded in a coastal lowland shizuoka prefecture along the pacific coast of japan four sand units deposited by tsunamis and one sand unit deposited by storm surge s were identified in a muddy marsh succession in a narrow coastal lowland along the pacific coast of central japan tsunamis in ad 1498 1605 1707 and 1854 that were related to large subduction zone earthquakes along the nankai trough and storm surges in 1680 and or 1699 were responsible for the deposition of these sand units these sand units are distinguished by lithofacies sedimentary structures grain size and mineral composition and radiocarbon ages their ages are supported by events in local historical records the tsunami deposits in the study area are massive or parallel laminated sands with associated intraclasts gravels draping mud layers and rarely a return flow subunit the storm surge deposits are devoid of these characteristics and are composed of groups of thin current ripple laminated sand layers the differences in sedimentary structures between the tsunami and storm surge deposits are attributed to the different characteristics of tsunami and storm waves

characterization of groundwater and surface water mixing in a semiconfined karst aquifer using time lapse electrical resistivity tomography groundwater flow in karst includes exchange of water between large fractures conduits and the surrounding porous matrix which impacts both water quality and quantity electrical resistivity tomography combined with end member mixing analysis emma and numerical flow and transport modeling was used to study mixing of karst conduit and matrix waters to understand spatial and temporal patterns of mixing during high flow and base flow conditions to our knowledge this is the first time emma and synthetic geophysical simulations have been combined here we interpret an 8 week time lapse electrical resistivity data set to assess groundwater surface mixing we simulate flow between the karst conduits and the porous matrix to determine fractions of water recharged to conduits that has mixed with groundwater stored in the pore space of the matrix using a flow and transport model in a synthetic time lapse resistivity inversion comparing the field and synthetic inversions our results enable us to estimate exchange dynamics spatial mixing and flow conditions results showed that mixing occurred at a volumetric flux of 56 m3 d with a dispersivity around 1 69 m during the geophysical experiment for these conditions it was determined that conduit water composition ranged from 75 groundwater during base flow conditions to less than 50 groundwater in high flow conditions though subject to some uncertainties the time lapse inversion process provides a means to predict changing hydrologic conditions leading to mixing of surface water and ground water and thus changes to water quantity and quality as well as potential for water rock reactions in a semiconfined sink rise system

semi distributed lumped model of a karst system under active management summary in this paper inverse modeling is used to characterize the regime of a karst aquifer subjected to extensive pumping in a conduit located upstream of its main outlet the systemic approach uses a transfer model that is based on computing the convolution integral of up to several signals e g efficient rainfall pumping to simulate flow rates and groundwater levels in both the karst conduit and the carbonate matrix at the aquifer outlet and in several parts of the catchment area the model is a semi distributed lumped model which simulates the hydrological response of a heterogeneous karst aquifer made up of different hydrologic compartments and is applied to the lez karst system france groundwater is abstracted near the system s major outlet at a higher rate than the low water spring discharge thereby mobilizing stored groundwater during low water periods active management the model s results are very satisfactory especially for the karst system outlet where the water levels are particularly well reproduced the model can also simulate the natural i e non pumping state of the karst system and thereby estimate the impact of active management on the water resource

origin and depositional model of wadi al batin and its associated alluvial fan saudi arabia and kuwait abstract wadi al batin alluvial fan which extends northeastward from hafar al batin in saudi arabia to cover parts of kuwait and southwestern iraq represents the largest of several other non active fans in central and south arabia evidence put forward suggests that like other comparable deposits of varying age in the arabian peninsula the al batin fan was deposited following downdip breaching of a scarp barrier by a large paleoriver further to the west which once flowed southward down the full length of the arabian peninsula the downdip breaching model offers an explanation of how the dibdibba gravels were introduced into kuwait it is postulated that the present southeasterly course of tigris euphrates rivers to the head of the arabian gulf was the last of the easterly diversions of the lower courses of the southward flowing paleoriver as its southern end shifted progressively by a sequence of lateral breaches through the central arabian scarplands it is the postulated existence of this huge former drainage system which is seen as the fundamental explanation for the occurrence of the dibdibba formation in kuwait and comparable gravels elsewhere on the eastern flank of the arabian peninsula after the initial phases of deposition of al batin alluvial fan its surface was dissected by floods from a reduced catchment area no longer carrying the same sediment load and therefore capable of eroding the fan dissection of the fan surface continued until the present wadi ai batin became sufficiently incised into the underlying tertiary bedrock to serve as a permanent outlet this led to the transport and secondary concentration of post dissection gravels along the perimeter of the ancient fan

great earthquakes of variable magnitude at the cascadia subduction zone comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate boundary ruptures of varying length implying great earthquakes of variable magnitude at the cascadia subduction zone inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis and relative amounts of coseismic subsidence and heights of tsunamis written records of a tsunami in japan provide the most conclusive evidence for rupture of much of the plate boundary during the earthquake of 26 january 1700 cascadia stratigraphic evidence dating from about 1600 cal yr b p similar to that for the 1700 earthquake implies a similarly long rupture with substantial subsidence and a high tsunami correlations are consistent with other long ruptures about 1350 cal yr b p 2500 cal yr b p 3400 cal yr b p 3800 cal yr b p 4400 cal yr b p and 4900 cal yr b p a rupture about 700 1100 cal yr b p was limited to the northern and central parts of the subduction zone and a northern rupture about 2900 cal yr b p may have been similarly limited times of probable short ruptures in southern cascadia include about 1100 cal yr b p 1700 cal yr b p 3200 cal yr b p 4200 cal yr b p 4600 cal yr b p and 4700 cal yr b p rupture patterns suggest that the plate boundary in northern cascadia usually breaks in long ruptures during the greatest earthquakes ruptures in southernmost cascadia vary in length and recurrence intervals more than ruptures in northern cascadia

aperiodic recurrence of geologically recorded tsunamis during the past 5500 years in eastern hokkaido japan 1 along hokkaido s pacific coast near the town of kiritappu sandy deposits in a muddy lagoon and on a nearby beach ridge plain provide evidence for 15 tsunamis between 200 and 6000 years ago additional sand beds at the lagoon probably represent the historical tsunamis of a d 1843 and 1894 we observed the sequences of sandy deposits in continuous slices 2 to 4 m deep some of the deposits consist of just a single sand bed whereas others contain multiple units of sand muddy sand or sandy mud and mud caps including plant detritus we also found at the lagoon a 17th century tsunami deposit that thickens and thins regardless of elevation or distance inland we bracketed the ages of most of the inferred tsunamis by radiocarbon dating of detritus mainly seeds and leaves at the lagoon and charcoal at the beach ridge plain from pretsunami and posttsunami beds tsunami dates computed from the bracketing ages commonly have uncertainties spanning 2 to 4 centuries within these uncertainties the inferred sequence of 15 prehistoric tsunamis at the lagoon beginning almost 6000 years ago can be matched tsunami by tsunami with the inferred history at the beach ridge plain 15 km away the sand sheet extents suggest that most of these tsunamis were larger than any generated at hokkaido in the last 200 years the intervals between these inferred outsized tsunamis average nearly 400 years but range widely from about 100 to about 800 years

aeolian processes and sand encroachment problems in kuwait abstract the surface of kuwait is carved in a calcretized clastic sequence of miocene pleistocene age mostly covered by a thin blanket of recent aeolian deposits fast rate of development and increase of human activities contributed to denudation of the vegetative cover and exposure of dry loose sediments to wind action at present kuwait is intensively subjected to aeolian actions manifested by frequent occurrences of sand and dust storms this dictated the need for regional understanding of the magnitude of the aeolian processes their behavior with man made establishments and their long and short term impacts a comparison between the nature and distribution of recent surface sediments in kuwait in 1979 and 1990 shows significant changes that reflect the work of aeolian processes during this period the direct impact of the enhancement of aeolian action is represented by the increase in the rate of sediment transport transportation of fine grained particles in suspension frequently occurs during dust storms usually initiated in southern iraq the particles migrate over kuwait as thick dust clouds and finally settle in the northern part of the arabian gulf bedload transport of sand or saltation frequently occurs during summer whenever wind speed reaches 5 4 m s the average annual sand drift rate in kuwait is about 20 m 3 m width 1 yr 1 the majority of the drift occurring during the period may august to the southeast bedform transport or sand dune movement is also recognized in kuwait sand dunes mostly occur as small barchans of about 3 m height the measured rate of movement of these barchans varies with height a barchan of average height usually moves about 20 m in nine monthes january august the remarkable high rate of sand transport and the increase in development activities in the desert areas are responsible for the enhancement of the sand encroachment problems in kuwait almost all installations roads and farms are significantly affected by the accumulation of considerable amounts of aeolian sand these problems have pronounced adverse environmental and economic impacts

a systematic review of geological evidence for holocene earthquakes and tsunamis along the nankai suruga trough japan the nankai suruga trough the subduction zone that lies immediately south of japan s densely populated southern coastline generates devastating great earthquakes magnitude 8 characterised by intense shaking crustal deformation and tsunami generation forecasting the hazards associated with future earthquakes along this 700 km long fault requires a comprehensive understanding of past fault behaviour while the region benefits from a long and detailed historical record palaeoseismology has the potential to provide a longer term perspective and additional crucial insights in this paper we summarise the current state of knowledge regarding geological evidence for past earthquakes and tsunamis along the nankai suruga trough incorporating literature originally published in both japanese and english and enhancing available results with new age modelling approaches we summarise and critically evaluate evidence from a wide variety of sources palaeoseismic evidence includes uplifted marine terraces and biota marine and lacustrine turbidites liquefaction features subsided marshes and tsunami deposits in coastal lakes and lowlands while 75 publications describe proposed evidence from 70 sites only a limited number provide compelling well dated evidence the best available records enable us to map the most likely rupture zones of twelve earthquakes that occurred during the historical period this spatiotemporal compilation suggests that the 1707 ce earthquake ruptured almost the full length of the subduction zone and that earthquakes in 1361 ce and 684 ce may have been predecessors of similar magnitude intervening earthquakes were of lesser magnitude highlighting the variability in rupture mode that characterises the nankai suruga trough intervals between ruptures of the same seismic segment range from 450 years during the historical period over longer timescales palaeoseismic evidence suggests intervals between earthquakes ranging from 100 to 700 years however these figures reflect a range of thresholds controlling the creation and preservation of evidence at any given site as well as the genuine intervals between earthquakes at present there is no geological data that suggest the occurrence of a larger magnitude earthquake than that experienced in 1707 ce however few studies have sought to establish the relative magnitudes of different earthquake and tsunami events along the nankai suruga trough alongside the lack of research designed to quantify the maximum magnitude of past earthquakes we emphasise issues over alternative hypotheses for proposed palaeoseismic evidence the paucity of robust chronological frameworks and insufficient appreciation of changing thresholds of evidence creation and preservation over time as key issues that must be addressed by future research

geomorphic changes in ras al subiyah area kuwait the ras al subiyah area is considered one of the most promising areas in kuwait for future development this development will include a new town called subiyah and its associated infrastructure this area is also being considered as the location for connection between boubyan island which is now undergoing major development and the kuwait mainland the present study investigates the geomorphology of the ras al sabiyah area in the northern sector of kuwait the study area is generally flat and it is located west of the jal az zor escarpment it is bordered on the east by the khor al sabiyah tidal channel and on the south by kuwait bay the area receives sediments from several sources currently the most important are aeolian sediments and the deposition of mud delivered through the khor al sabiyah from the iraqi marshes the study area has been subjected to severe environmental changes due to the gulf wars and the drainage of iraqi marshes and the associated artificial changes in fluvial system twenty two surface sediments were collected from the ras al subiyah area samples were collected to include the main geomorphologic characteristic features of the study area field observations and remote sensing images from 1990 and 2001 were used to produce an updated geomorphologic map for the ras al subiyah and a map showing geomorphic changes between 1990 and 2001 grain size of the surface sediment ranges from gravel to medium sand in general grain size statistical analysis indicates that most of the areas are composed of two or more classes of sands transported and deposited from different sources including aeolian sabkhas river and the bays the variability in the grain size statistical parameters may be attributed to the complexity of surface morphology as well as the diversity in the type of depositional environment in the ras al subiyah area the total area subjected to change during the 12 year period 1990 2001 is about 32 km2 as calculated using gis techniques

a multicell karstic aquifer model with alternative flow equations a multicell groundwater model was constructed to investigate the potential improvement in the modelling of karstic aquifers by using a mixed equation suitable for both the free surface and pressure flow conditions in karstic conduits to estimate the model parameters the shuffled complex evolution sce optimisation method was used this ensured a fast and objective model calibration the model was applied to two real world karstic aquifers and it became clear that in case of absence of water level measurements the use of the mixed equation did not improved the performance in cases where both spring discharge and water level measurements were available the use of the mixed equation proved to be advantageous in reproducing the features of the observed time series especially of the water level

modelling of the functioning of karst aquifers with a reservoir model application to fontaine de vaucluse south of france summary this work deals with a rainfall discharge model applied to a well known karst aquifer a new approach is developed in order to minimize the fitting parameters here some of the model parameters do not result from a simple fitting as it was the case with earlier models i e some of them were assessed from the hydrograph analysis the conceptual model of the functioning is based on a production function based on a simple calculation of effective rainfall and a transfer function consisting of two reservoirs a slow discharge reservoir transfers the low flow and a rapid discharge reservoir feeds the high flow the model has three fitted parameters plus one for its initialisation three parameters are deduced from the hydrograph analysis over the entire time series for example the recession coefficient of the slow discharge reservoir is determined from the hydrodynamic analysis of the recession mangin a 1975 contribution a l etude hydrodynamique des aquiferes karstiques 3eme partie constitution et fonctionnement des aquiferes karstiques annales de speleologie 30 1 210 124 this model was tested over a ten years period on the fontaine de vaucluse french karst system the first hydrological year is used for fitting the model the nine other cycles validate the modelling the good quality of the model is proved by the nash criterion of 92 3 on the validation period moreover the simulation results were validated by a statistical analysis of measured and simulated time series the model successfully simulates both the high and low flow at the same time also it estimates the water volumes available in the different parts of the aquifer and it proposes a management tool capable of predicting the evolution of the discharge in different climate conditions

kuwaiti dolocrete petrology geochemistry and groundwater origin abstract near surface sediments in southern kuwait show extensive development of duricrusts the host materials are siliciclastic sandstones of the post eocene kuwait group inland the duricrusts are dominantly pedogenic calcrete with some silcrete and gypcrete whereas within 10 20 km of the coast dolomite is the dominant duricrust mineral both these dolocretes and the inland calcretes display a similar maturation sequence in which carbonate rich nodules develop and coalesce carbonate progressively replacing and displacing detrital grains the dolomite of the dolocretes forms mosaics of crystals typically 10 70 m in size varying from simple rhombs to spherulites an intermediate morphology named artichoke dolomite from its appearance in sem is particularly abundant authigenic palygorskite is associated with the dolomite dissolution of cores or zones within dolomite crystals has occurred calcite is present as sparry crystals always post dating dolomite and is the expected precipitate from present day soil and groundwaters chemical analyses of dolomite show highly negative values of 13 c to 10 7 pdb and 18 o varying from 0 6 to 3 3 pdb the oxygen isotope values are interpreted as reflecting evaporation of a marine based fluid manganese values of around 1000 ppm show that this fluid was reducing strontium data show variability reflecting mineral fluid reactions the general absence of metastable carbonates and presence of zoning in dolomite crystals suggests that meteoric dilution of seawater also occurred given that the duricrusts lack biogenic features the light carbon isotope values are taken to indicate oxidation of seeping hydrocarbons the dolocretes are interpreted as groundwater precipitates near the water table of a brackish water body formed at a time of higher relative sea level than today

geomorphological analysis of paleo drainage systems and their environmental implications in the desert of kuwait a well developed drainage network is carved in the hard calcretized and gypcretized gravelly sand of the pleistocene dibdibba formation in northern kuwait the present day aridity suggests that these drainages were developed during pluvial episodes that took place in the post pleistocene time and therefore are considered as paleo drainage detailed morphometrical analysis of the endoeric drainage systems was performed and the degree of correlation among their different morphometric parameters was investigated based on these parameters the studied drainage basins are statistically grouped into three groups such grouping was confirmed by discriminant analysis the categorical data analysis demonstrated the dependence of these groupings on the surface geology regional topography and local geomorphological settings infiltration measurements revealed that the drainage bedrocks have a low infiltration rate 20 cm h 1 whereas the drainage fill deposits have a relatively high infiltration rate 67 30 cm h 1 the impact of the drainage system pattern and morphometry on the hydrological conditions is discussed and potential near surface low salinity to freshwater aquifers is delineated the role of the studied drainage systems in the occurrence of mobile sand and sand dunes rainwater harvesting and land capability are discussed

little late holocene strain accumulation and release on the aleutian megathrust below the shumagin islands alaska can a predominantly creeping segment of a subduction zone generate a great m 8 earthquake despite russian accounts of strong shaking and high tsunamis in 1788 geodetic observations above the aleutian megathrust indicate creeping subduction across the shumagin islands segment a well known seismic gap seeking evidence for prehistoric great earthquakes we investigated simeonof island the archipelago s easternmost island and found no evidence for uplifted marine terraces or subsided shorelines instead we found freshwater peat blanketing lowlands and organic rich silt and tephra draping higher glacially smoothed bedrock basal peat ages place glacier retreat prior to 10 4 ka and imply slowly rising 0 2 m ka relative sea level since 3 4 ka storms rather than tsunamis probably deposited thin discontinuous deposits in coastal sites if rupture of the megathrust beneath simeonof island produced great earthquakes in the late holocene then coseismic uplift or subsidence was too small 0 3 m to perturb the onshore geologic record

an integrated linear non linear flow model for the conduit fissure pore media in the karst triple void aquifer system most karstic aquifer media may be characterized as the triple void media with highly varied hydraulic properties including matrix pore fissure and conduit in which liner flow may co exist with non linear flow in this paper an attempt is made to couple linear flow with non linear flow in a single unified flow governing equations by introducing the concept of equivalent hydraulic conductivity ehc and deriving a general darcy s law for various flow the expression of ehc in the karst conduit and fissure are also derived the procedures of numerical implementation are demonstrated via an ideal model and a case study of karst aquifer system in the beishan ore formation area guangxi autonomous region china

simplified physically based models for free surface flow in karst systems abstract most karst aquifers are characterized as a dual flow system comprised of a highly conductive conduit network embedded in a low porosity matrix the conduits are hydraulically connected to the matrix and behave either as a drain or a source depending on the recharge conditions simplified physically based models are herein employed to simulate the spring outflow for such aquifer systems the processes consist of a free surface flow in the conduit that is interacting laterally with a laminar groundwater flow in the surrounding matrix the conduit is subject to a concentrated recharge at its upstream end while the groundwater aquifer is subject to a diffuse recharge over its contributing surface area the flow system is described by a coupled system of partial differential equations the conduit flow is approximated by the kinematic wave equation and the groundwater flow by the linearized boussinesq equation the governing equations are solved using the laplace transform method after an appropriate linearization of the nonlinear coefficient the derived spring discharge models are a function of three dimensionless parameters the time lag parameter the lumped conduit parameter and the aquifer parameter the simulation results highlight the contrast between pressure driven and gravity driven flows and the importance of the conduit matrix interaction on the response of the karst system application of the models on real karst aquifers demonstrates their effectiveness in simulating the observed spring hydrograph using lumped physical parameters of the karst system

new insights of tsunami hazard from the 2011 tohoku oki event we report initial results from our recent field survey documenting the inundation and resultant deposits of the 2011 tohoku oki tsunami from sendai plain japan the tsunami inundated up to 4 5 km inland but the 0 5 cm thick sand deposit extended only 2 8 km 62 of the inundation distance the deposit however continued as a mud layer to the inundation limit the mud deposit contained high concentrations of water leachable chloride and we conclude that geochemical markers and microfossil data may prove to be useful in identifying the maximum inundation limit of paleotsunamis that could extend well beyond any preserved sand layer our newly acquired data on the 2011 event suggest that previous estimates of paleotsunamis e g 869 ad j gan earthquake and tsunami in this area have probably been underestimated if the 2011 and 869 ad events are indeed comparable the risk from these natural hazards in japan is much greater than previously recognized

tsunamis and submarine landslides in suruga bay central japan caused by nankai suruga trough megathrust earthquakes during the last 5000 years abstract magnitude 8 megathrust earthquakes that have generated large tsunamis with wave heights of 5 m in coastal areas of southwestern japan have occurred every 100 150 years along the nankai suruga trough which marks the convergent boundary between the eurasian and philippine sea plates using sedimentological geochemical and paleontological analyses as well as 14c dating we examined tsunami deposits in 12 sediment cores collected from the hamatome lowland yaizu plain shizuoka which faces the suruga trough four sandy tsunami deposits sands 1 4 are identified in sediments deposited during the last 5000 years sand 1 was deposited between 805 and 405 bc suggesting that only one tsunami left a sedimentological imprint in the hamatome lowland lagoon during the period of 4000 years between 3090 and 2913 bc and the ad 1096 eicho tokai earthquake this very low frequency of tsunami inundation may suggest that this tsunami was larger than those typically associated with megathrust earthquakes sands 2 4 are correlated with tsunamis associated with the eicho tokai ad 1361 shohei koan and ad 1498 meio tokai earthquakes respectively our data indicate that a sand spit which had previously protected the lagoon from oceanic waves was abruptly destroyed following the ad 1096 eicho tokai earthquake and did not re form at the same location this disappearance of the sand spit is inferred to have involved an earthquake induced submarine landslide the data presented in this paper together with information obtained from historical documents indicates that m8 megathrust earthquakes in ad 1096 and ad 1498 caused submarine landslides in the study area resulting in coastal subsidence and damage to coastal areas additional to that caused by the tsunamis

double porosity models for a fissured groundwater reservoir with fracture skin theories of flow to a well in a double porosity groundwater reservoir are modified to incorporate effects of a thin layer of low permeability material or fracture skin that may be present at fracture block interfaces as a result of mineral deposition or alteration the commonly used theory for flow in double porosity formations that is based upon the assumption of pseudo steady state block to fissure flow is shown to be a special case of the theory presented in this paper the latter is based on the assumption of transient block to fissure flow with fracture skin under conditions where fracture skin has a hydraulic conductivity that is less than that of the matrix rock it may be assumed to impede the interchange of fluid between the fissures and blocks resistance to flow at fracture block interfaces tends to reduce spatial variation of hydraulic head gradients within the blocks this provides theoretical justification for neglecting the divergence of flow in the blocks as required by the pseudo steady state flow model coupled boundary value problems for flow to a well discharging at a constant rate were solved in the laplace domain both slab shaped and sphere shaped blocks were considered as were effects of well bore storage and well bore skin resultsmore obtained by numerical inversion were used to construct dimensionless type curves that were applied to well test data for a pumped well and for an observation well from the fractured volcanic rock terrane of the nevada test site less

contiguous rupture areas of two nankai trough earthquakes revealed by high resolution tsunami waveform inversion 1 we have developed a new method for inverting tsunami waveforms that reveals considerable detail in megathrust slip during subduction zone earthquakes previous methods have ensured compliance with the shallow water theory used to compute tsunami waveforms by using large subfaults that generate only long wavelength seafloor deformation we show that a better approach is to use small subfaults coupled with a smoothing criterion that ensures compliance with the shallow water approximation in an application of the method to historical earthquakes in the nankai trough southwestern japan we find that the areas with slip 1 m for the earthquakes of 1944 and 1946 which ruptured adjacent segments of the subduction zone are separated by a sharp non overlapping boundary this establishes that interseismic accumulation of strain energy extends very close to the boundary between rupture zones and strongly suggests that this boundary is associated with a physical barrier to rupture

spheroidal dolomites origin by hydrocarbon seepage spheroidal dolomite cements are a pervasive and distinctive feature in five exposed lithologies of different geological age in kuwait the spheroids range in diameter from 5 350 m have concentric zones and nuclei of fluid inclusions with or without a radial fabric and compositions varying from near stoichiometric to ca56 mg44 all spheroids appear to be primary in origin with no evidence of replacement some concentric zones show selective calcitization and or leaching most of these features are confined to within 30 m of the surface consequently spheroidal dolomites recognizable at depth in ancient sequences may be indicative of a local unconformity the dolomite distributions are areally correlative with known areas of hydrocarbon seepage the latter being confined to prominent oil field anticlinal trends it is proposed that the dolomitization was caused by groundwaters carrying hydrocarbons to the surface which were then oxidized to carbon dioxide the gas bubbles may have acted as nuclei for spheroid growth with a possible inducement by bacteria which have an affinity for hydrocarbons the implication is that the regional distribution of spheroidal dolomites may be an indicator of a potential reservoir facies at depth

derivation of effective hydraulic parameters of a karst aquifer from discharge hydrograph analysis in well developed karst terrains three or more distinct portions of the karst continuum can be identified from hydrographs of springs issuing from the karst aquifer hydrographs from two karst springs within the same drainage basin at the crane naval surface warfare center indiana have been analyzed and ratios of transmissivity and specific yield t sy have been established for the conduit and diffuse flow systems these ratios have been compared with values of t derived from aquifer tests so that independent values of sy can be calculated for the diffuse system similarly if the value of sy is assumed to be 1 0 for a pure conduit then independent values of t can be calculated for this end member of the karst continuum the values of t and sy derived from this study are similar to values obtained from a dye trace of the conduit dominated flow system and of values derived from aquifer tests of the diffuse flow system values of t for the conduit system of these springs may need to be established at a local scale while the values for the diffuse flow system may be applicable at a regional scale a hydrograph separation using isotopic data suggests that the intermediate flow system represents a mix of water from the conduit and diffuse flow systems if this portion of the hydrograph is a truly mixing phenomena ratios of t sy cannot be determined from the hydrograph analysis presented herein however if instead the intermediate flow system represents water released from a third reservoir such as small fractures ratios of t sy can be established for the intermediate flow system

an overview of the tertiary geology and hydrogeology of the northern part of the arabian gulf region with special reference to kuwait abstract tertiary sediments constitute the main source of usable groundwater in kuwait tectonics depositional environment lithology and the hydrogeology of these sediments have been reviewed on a regional scale with special reference to kuwait the review showed that kuwait was situated at the boundary of the stable shelf towards southwest and the unstable shelf towards northeast throughout the tertiary period the tertiary sedimentation started in this area with a marine transgression in the palaeocene shallow marine to sabkha conditions prevailed in the area until the end of the eocene a carbonate evaporite sequence umm er radhuma rus and dammam formation was deposited during this period the sea regressed at the end of eocene and a widespread unconformity causing the absence of oligocene deposits over most of the area marked the event the karstification of the dammam limestone formation that provides localized easier pathways for ground water took place during this period the deposition of the clastic sediments of the kuwait group and its equivalents on the stable shelf under mostly continental conditions started in the early miocene the tertiary aquifers of the area are recharged by occasional rainstorms in the outcrops of saudi arabia and iraq the water flows towards the north and east in the direction of the regional dip and discharges along the present day coast of the gulf the water quality deteriorates in the same direction being more mineralized as it flows through the aquifers the aquifers are presently being exploited at a comparatively high rate since the aquifers extend beyond the political boundaries cooperation among the countries of the region is recommended to ensure the optimum utilization of the scarce water resources of this desert environment

morphological and morphostructural features of kuwait abstract morphostructural analysis and interpretation of the geomorphic features of the surface of kuwait are essentially dependant on the recognition of the structural configuration of the top of the upper eocene dammam formation and its influence on the overlying sediments of the kuwait group the top surface of the dammam formation has an undulatory form representing a series of n s to nnw sse trending domal and flexural structures this surface has regulated to a variable extent the depositional regime and thickness of the overlying kuwait group structures of the dammam formation have directly left an impression on the surface as morphostructural forms and also indirectly controlled the geomorphic forms of the overlying sediments fifteen geomorphic zones characterized by distinct physiographic patterns slope gradients and dependant features are presented on a map data based on the recognition of drainage patterns and slope characteristics were incorporated significant deflection in topographic contours was also identified and geomorphic discontinuities and anomalies were delineated further treatment of the geomorphic zonation data with input from existing geological structural and tectonic data has resulted in the construction of the first morphostructural map of kuwait

multi proxy evidence for small historical tsunamis leaving little or no sedimentary record abstract there has been considerable progress in tsunami research in recent years yet most work has been focussed on identifying and understanding the evidence of large events this study aimed to identify the evidence of small historical tsunamis in lyttelton harbour new zealand the study area has been inundated by multiple relatively small historical tsunamis that left atypical sedimentary evidence no sand or no sediment shallow trenches revealed discontinuous layers of small grey mud clasts at various depths across the study area most likely transported from the nearby tidal flats the origin of these mud clast layers was investigated using a multi proxy approach comprising sedimentological geochemical and diatom analyses complemented by dating from 137cs activity profiles and historical data subtle variations consistent with inclusions of marine mud such as a decrease in organic content and magnetic susceptibility and increases in geochemical markers e g ca kcps k kcps k rb si rb and sr rb were found in the sediment profile variations in diatom assemblages suggesting a marine influence were also recorded at similar depths aligning with layers of mud clasts using 137cs activity profiles and historical data these deposits were attributed to the 1960 chile valdivia and 1964 alaska tsunamis as well as a possible earlier event sedimentary evidence for the 2010 chile maule tsunami was not found at the study site but geochemical analysis of surface samples revealed marked changes in ca cl sr and ti concentrations indicative of a change from a terrestrial to marine influence this was used to identify the landward extent of inundation by the 2010 event ultimately this study shows that a broad multi proxy analysis can distinguish even the subtle signatures of an inconspicuous deposit laid down by a small tsunami

a double medium approach to simulate groundwater level variations in a fissured karst aquifer abstract karst aquifers are known for their complex flow mechanisms produced by the high spatial heterogeneity of void distribution this study aims at confirming and enhancing the understanding of these flow mechanisms in a fissured karst aquifer using flow simulation with a double medium approach groundwater level gwl variations of the studied site a 17 km2 topographic hill located in burgundy france are monitored hourly through 18 boreholes 3 karstic resurgences and the outlet river discharge of the catchment basin 40 km2 the gerke and van genuchten double porosity model is implemented in the metis code and used to simulate gwl variations with a matrix and a fracture medium model parameters are calibrated by fitting a simulated fracture medium gwl to measured gwl for four boreholes that are representative of the topographic hill hydrodynamics the double medium approach succeeds in reproducing measured fast gwl responses after recharge events that are not reproduced by a single medium approach investigating the model parameters impact on simulated gwl variations and the exchange flow between the two media allows the conceptualization of the physical structure and the hydrodynamic mechanisms of the fissured karst aquifer the spatial organization of parameters is observed and indicates areas of higher fracture density producing rapid gwl responses in contrast to lower fracture density areas which produce slower and higher gwl responses the fracture medium hydraulic parameters and the exchange parameter controlling the matrix fracture interface properties are the most influential parameters for the simulated fracture medium gwl and the exchange flow between the matrix and the fracture medium during a recharge event calibrated fracture medium hydraulic conductivity and effective porosity vary respectively from 6 3e to 05 m s 1 and 0 3 to 3 2e 04 m s 1 and 2 4 and the exchange parameter varies from 2 9e 10 m 1 s 1 to 6 5e 10 m 1 s 1 matrix medium hydraulic conductivity variations have little impact on the simulation results while matrix medium effective porosity affects slightly simulated gwl values vary from 11 to 17 finally this study shows the gerke and van genuchten double porous medium validity for the simulation of groundwater level in a fissured karst aquifer

the euphrates tigris karun river system provenance recycling and dispersal of quartz poor foreland basin sediments in arid climate we present a detailed sediment provenance study on the modern euphrates tigris karun fluvial system and mesopotamian foreland basin one of the cradles of humanity our rich petrographic and heavy mineral dataset integrated by sand geochemistry and u pb age spectra of detrital zircons highlights the several peculiarities of this large source to sink sediment routing system and widens the spectrum of compositions generally assumed as paradigmatic for orogenic settings comparison of classical static versus upgraded dynamic petrologic models enhances the power of provenance analysis and allows us to derive a more refined conceptual model of reference and to verify the limitations of the approach sand derived from the anatolia zagros orogen contains abundant lithic grains eroded from carbonates cherts mudrocks arc volcanics obducted ophiolites and ophiolitic melanges representing the exposed shallow structural level of the orogen with relative scarcity of quartz k feldspar and mica this quartz poor petrographic signature characterizing the undissected composite tectonic domain of the entire anatolia iranian plateau is markedly distinct from that of sand shed by more elevated and faster eroding collision orogens such as the himalaya arid climate in the region allows preservation of chemically unstable grains including carbonate rock fragments and locally even gypsum and reduces transport capacity of fluvial systems which dump most of their load in mesopotamian marshlands upstream of the arabian persian gulf allochemical carbonate factory quartz poor sediment from the anatolia zagros orogen mixes with quartz rich recycled sands from arabia along the western side of the foreland basin and is traced all along the gulf shores as far as the rub al khali sand sea up to 4000 km from euphrates headwaters

sources and genesis of the pleistocene gravelly deposits in northern kuwait abstract the dibdibba formation is of pleistocene age and consists of a fluviatile sequence of ungraded often cross bedded sand and gravels intercalated with minor sandy clay layers it occurs in the northern desert of kuwait as subparallel elongated ridges trending ne sw structures and mineralogy of the dibdibba deposits suggest that they have been derived from the basement complex of the northeastern area of saudi arabia as sheet floods and deposited in the alluvial fan of the wadi ar rimmah al batin valley system floods transporting these deposits were intermittent the gravelly bands were deposited during severe floods and the sandy beds during relatively quiet floods

significance and origin of very large regulating power of some karst aquifers in the middle east implication on karst aquifer classification summary karst aquifers are the main groundwater resource in lebanon as well as in most mediterranean countries most of them are not exploited in a sustainable way partly because their characteristics remain unknown karst aquifers are so complex that the assessment of their resource and their exploitable storage requires an analysis of their whole functioning particularly by analysing the spring hydrograph among all various methods the method proposed by mangin aims to characterize at the same time the recharge conditions and the storage and recession of the saturated zone by analyzing the spring hydrograph this method defines two parameters the infiltration delay i and the regulating power k which are the roots of a classification of karst systems this classification makes the distinction between karst and porous aquifers considering the value of the regulating power k is assumed to be lower than 0 5 in karst and between 0 5 and 1 for all other aquifers 1 being the upper limit the study of karst aquifers in lebanon shows values of k 0 5 and even 1 former data from the literature show that other karst springs in middle east have comparable characteristics in fact what is not considered by mangin and others k is equivalent to a mean residence time in years of water in the saturated zone so long residence times are normally observed in poorly karstified aquifers or containing abandoned not functioning karstification the geological framework in which the studied springs are located in fact shows that these aquifers have been subject to a long complex evolution as a consequence of the base level rising this rising produced the flooding of the successive karst drainage network which does not really function anymore and provides a large storage capacity to the aquifer the very interesting properties of these aquifers make them prime targets for fulfilling the increasing needs of water

modelling the hydrologic functions of a karst aquifer under active water management the lez spring a rainfall discharge model is applied to an aquifer characterized by active groundwater management the lez karst aquifer in the south of france groundwater is withdrawn by pumping in the main drain 400 m upstream from the main spring and 48 m below the aquifer overflow level a reservoir model was developed to characterize the functioning of this aquifer it is based on a conceptual model of the karst aquifer that takes into account flow through both the saturated zone and the unsaturated infiltration zone both rapid and slow flow in the infiltration zone and flow in the saturated zone are modelled since pumping withdraws groundwater from the main drain of the saturated zone modules characterizing various pumping practices are taken into account in the saturated zone reservoir the model simultaneously simulates spring discharge and water levels in the drain which characterize the saturated zone of the karst the groundwater reserves stored in the saturated zone can then be estimated the model can be used for water management since runoff and overflow from the aquifer feeding the lez river depend on the degree of saturation of the aquifer the model could be used for the flood management

paleoecological evidence for coastal subsidence during five great earthquakes in the past 1500 years along the northern onshore continuation of the nankai subduction zone abstract during the last 1500 years a marsh on the north coast of suruga bay central japan has experienced as many as five rapid submergence events this conclusion is supported by analyses of depositional facies and pollen and diatom assemblages in sediment cores from the ukishimagahara lowland on the footwall side of the fujikawa kako fault zone fkz the northern extension of the nankai and suruga troughs light colored silt or clay beds 30 50 cm thick deposited as the result of submergence events that drowned the marshland cover terrestrial peat or humic soils produced by the marshland vegetation radiocarbon ages and dated tephras suggest that in this lowland submergence events have occurred at aperiodic intervals of 100 400 years atmospheric phenomena can cause increased precipitation and flooding by rivers and typhoons but they cannot explain the cyclic submergence events at centennial timescales during the late holocene sea levels have been declining relative to land around the japanese islands so high sea levels cannot explain the periodic submergence of the lowland the most likely cause of these events therefore is coseismic subsidence of the lowland related to great earthquakes m8 0 occurring in the fkz or the suruga trough coseismic coastal deformation around the study area during the 1854 ansei tokai earthquake supports this hypothesis