cassini imaging science initial results on phoebe and iapetus the cassini imaging science subsystem acquired high resolution imaging data on the outer saturnian moon phoebe during cassini s close flyby on 11 june 2004 and on iapetus during a flyby on 31 december 2004 phoebe has a heavily cratered and ancient surface shows evidence of ice near the surface has distinct layering of different materials and has a mean density that is indicative of an ice rock mixture iapetus s dark leading side cassini regio is ancient heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief local albedo variations within and bordering cassini regio suggest mass wasting of ballistically deposited material the origin of which remains unknown

negative creep of soils after unloading the deformation of soils cannot be stable immediately but continues to expand over time even under constant pressure in this paper the expansive deformation over time when effec

mass movement and landform degradation on the icy galilean satellites results of the galileo nominal mission the galileo mission has revealed remarkable evidence of mass movement and landform degradation on the icy galilean satellites of jupiter weakening of surface materials coupled with mass movement reduces the topographic relief of landforms by moving surface materials down slope throughout the galileo orbiter nominal mission we have studied all known forms of mass movement and landform degradation of the icy galilean satellites of which callisto by far displays the most degraded surface callisto exhibits discrete mass movements that are larger and apparently more common than seen elsewhere most degradation on ganymede appears consistent with sliding or slumping impact erosion and regolith evolution sliding or slumping is also observed at very small 100 m scale on europa sputter ablation while probably playing some role in the evolution of ganymede s and callisto s debris layers appears to be less important than other processes sputter ablation might play a significant role on europa only if that satellite s surface is significantly older than 108 years far older than crater statistics indicate impact erosion and regolith formation on europa are probably minimal as implied by the low density of small craters there impact erosion and regolith formation may be important on the dark terrains of ganymede though some surfaces on this satellite may be modified by sublimation degradation while impact erosion and regolith formation are expected to operate with the same vigor on callisto as on ganymede most of the areas examined at high resolution on callisto have an appearance that implies that some additional process is at work most likely sublimation driven landform modification and mass wasting the extent of surface degradation ascribed to sublimation on the outer two galilean satellites implies that an ice more volatile than h2o is probably involved

estimating the ocr in uniform cohesive soil with cone penetrometer tests considering soil structure and index properties a basic empirical approach to estimate the preconsolidation stress and overconsolidation ratio ocr in uniform cohesive soils using the cone penetration and piezocone tests uses a correlation fact

landslides on charon abstract we investigated five large landslides identified in the serenity chasma region of charon the identification of these landslides involved a search for these features in images taken by cameras onboard the new horizons spacecraft various landslide properties were analyzed based on their morphologies using a digital terrain model of the region we found that landslides are confined to the walls of the large normal fault scarps that make up serenity chasma based on extensive landslide runout lengths l relative to their drop heights h we classified these features as long runout landslides by analyzing their geometries we estimated the friction coefficients of the landslide material h l to be between 0 15 to 0 31 and the runout efficiencies l h to be between 3 2 and 6 8 we also estimated that the specific energy released during landslide motion ranged from 0 8 to 1 3 kj kg 1 these amounts of energy were too low to have generated significant melt around landslide particles

calculated and observed behaviour of a reinforced embankment over soft compressible soil the finite element analysis of an instrumented geotextile reinforced test embankment is described and the results are compared with the field measurements the embankment was constructed to failure on a soft compressible organic clayey silt deposit at sackville new brunswick the analysis adopts a fully coupled large strain elasto plastic biot consolidation model with modified cam clay material behaviour it is shown that the analysis captured many features of the embankment behaviour however it is concluded that the elasto plastic modified cam clay formulation is not adequate for accurately and simultaneously predicting the multiple characteristics e g vertical and horizontal deformations pore pressures and geotextile strains of the embankment behaviour primarily because of the rate sensitive nature and the consequent progressive failure of the foundation soil key words embankment geotextile reinforcement analysis field behaviour deformations

friction of ice on ice 1 new measurements have been made of the friction coefficient of freshwater polycrystalline ice sliding slowly 5 10 8 to 1 10 3 m s 1 upon itself at temperatures from 98 to 263 k under low normal stresses 98 kpa sliding obeys coulomb s law the shear stress is directly proportional to the normal stress across the interface while cohesion offers little contribution to frictional resistance the coefficient of kinetic friction of smooth surfaces varies from k 0 15 to 0 76 and at elevated temperatures 223 k exhibits both velocity strengthening at lower velocities 10 5 to 10 4 m s 1 and velocity weakening at higher velocities strengthening and weakening are attributed to creep deformation of asperities and localized melting respectively at intermediate temperatures of 173 and 133 k the kinetic coefficient appears to not exhibit significant dependence upon velocity however at the low temperature of 98 k the coefficient of kinetic friction exhibits moderate velocity strengthening at both the lowest and the highest velocities but velocity independence over the range of intermediate velocities no effect was detected of either grain size or texture over the range of roughness 0 4 10 6 m ra 12 10 6 m a moderate effect was detected where k ra0 08 slide hold slide experiments revealed that the coefficient of static friction increases by an amount that scales logarithmically with holding time implications of the results are discussed in relation to shearing across tiger stripe faults within the icy crust of saturn s enceladus sliding of the arctic sea ice cover and brittle compressive failure of cold ice

mass wasting and ground collapse in terrains of volatile rich deposits as a solar system wide geological process the pre galileo view the polar terrains of mars are covered in many places with irregular pits and retreating scarps as are some of the surfaces of the outer planet satellites these features are interpreted by us as diagnostic of exogenic degradation due to the loss of a volatile rock forming matrix or cement in this study we propose that sublimation degradation is a plausible solar system wide geological process candidate examples have been identified on mars io and triton and possibly europa and ganymede we envision this process as having two end member expressions pits and scarps for which we hypothesize two end member mechanisms massive localized lenses and areally extensive basal layers in this study we focus on the role this process may play on the surfaces of the galilean satellites our principle modeling results are that for these satellites h2s co2 and nh3are the only viable candidate volatiles for sublimation degradation of landforms in light of galilean satellite cosmochemistry for io s polar regions only h2s and then only from slopes that face the sun and have thin lags is volatile enough to cause the observed sublimation induced erosion at those latitudes so2is not a viable candidate as an agent of erosion especially for these polar landforms in the case of europa only co2and h2s are viable candidates given surface age constraints both species could be efficient eroders in nonpolar regions h2s could generate erosion within the polar regions if the deposition and erosion conditions were essentially identical as those we invoked for io s polar regions for ganymede and callisto nh3might be an agent of erosion in equatorial terrains of great age the sublimation of co2and h2s is much more robust than nh3 the much slower rate of sublimation degradation from nh3might be detectable by galileo and used as a compositional indicator

case history examples of estimating the ocr in structured and structured organic cohesive soil with field vane tests using the shansep based method the accurate estimation of the preconsolidation stress and overconsolidation ratio ocr in uniform cohesive soils using the field vane test is influenced by the combined effects of soil type and p

the use of a combination frequency technique to measure the surf zone bubble population there are great benefits to sizing bubbles using a two frequency technique which examines the appearance of sum and difference signals generated by the interaction between a resonant bubble pulsation and a much higher frequency imaging beam this paper presents the results from using the technique to size bubbles in the ocean surf zone and details the pulsation model used to calibrate the returned data such that the height of the bubble scattered signal can be related to the number of resonant bubbles of that size it also shows how ambiguities and inaccuracies brought on through turbulence and the substantial off resonance nature of the signal which affected earlier oceanic tests using the same method can be identified in the returned signal or removed from the estimate during the data processing

clutter suppression and classification using twin inverted pulse sonar in ship wakes twin inverted pulse sonar twips is here deployed in the wake of a moored rigid inflatable boat rib with propeller turning and then in the wake of a moving tanker of 4580 dry weight tonnage the whitchallenger this is done first to test its ability to distinguish between scatter from the wake and scatter from the seabed and second to test its ability to improve detectability of the seabed through the wake compared to conventional sonar processing techniques twips does this by distinguishing between linear and nonlinear scatterers and has the further property of distinguishing those nonlinear targets which scatter energy at the even powered harmonics from those which scatter in the odd powered harmonics twips can also in some manifestations require no range correction and therefore does not require the a priori environment knowledge necessary for most remote detection technologies

air borne sound generated by sea waves this paper describes a semi empiric model and measurements of air borne sound generated by breaking sea waves measurements have been performed at the baltic sea shores with different slopes and sediment types have been investigated results showed that the sound pressure level increased from 60 db at 0 4 m wave height to 78 db at 2 0 m wave height the 1 3 octave spectrum was dependent on the surf type a scaling model based on the dissipated wave power and a surf similarity parameter is proposed and compared to measurements the predictions show satisfactory agreement to the measurements

evaluation of the predictive ability of two elastic viscoplastic constitutive models two elastic viscoplastic constitutive formulations are evaluated using laboratory and field data from sackville new brunswick and gloucester ontario both constitutive models have been implemented in a finite element program and formulated for undrained analysis and fully coupled analysis based on biot consolidation theory a laboratory study of the rate sensitive behaviour of sackville clay is described the response of sackville clay during consolidated anisotropic undrained cau triaxial creep cau triaxial compression and incremental oedometer consolidation is compared with the calculated behaviour the comparisons demonstrate the general ability of three parameter elastic viscoplastic constitutive models to satisfactorily describe the rate dependent behaviour of sackville clay the measured response of gloucester clay during long term rowe cell consolidation tests is compared with the calculated behaviour and the predictive ability of both constitutive formulations is evaluated using the field p

modelling time dependent behaviour of murro test embankment this paper investigates the time dependent behaviour of murro test embankment in finland the embankment was built in 1993 on a soft natural clay deposit which exhibits large strain anisotropy destructuration and viscosity the study is based on extensive experimental data from triaxial and oedometer tests on intact and reconstituted soil samples which shed light on the influence of time on mechanical properties including testing designed for studying soil anisotropy and destructuration the interpretation of the results is done in the framework of a recently developed elasto viscoplastic model evp sclay1s which is used to simulate the soft soil deposit coupled with biot s consolidation theory the determination of model parameters from the test results demonstrates that the model can be relatively easily used for practical applications using these parameters two dimensional finite element analyses have been made as large deformation analysis the comparisons between calculations and measurements de

modeling the viscoplastic behaviour of clays during consolidation application to berthierville clay in both laboratory and field conditions to analyze the effects of strain rate and viscoplastic strain on consolidation of natural clay this paper presents a nonlinear viscoplastic model in which viscoplastic behaviour is modeled by a un

creep and consolidation of a stiff clay under saturated and unsaturated conditions in this paper the one dimensional 1d time dependent behaviour of natural and reconstituted london clay samples under saturated and unsaturated conditions is studied for this purpose a set of 1

shallow normal fault slopes on saturnian icy satellites fault dips are a function of the coefficient of internal friction i of the lithospheric material laboratory deformation experiments of h2o ice at conditions applicable to icy bodies yield 0 i 0 55 such that normal faults dip between 45 and 59 we tested the hypothesis that normal faults on icy bodies reflect these values by using digital elevation models to examine geometries of large extensional systems on three saturnian satellites analyzed faults within ithaca chasma on tethys and avaiki chasmata on rhea all exhibit shallower than predicted topographic slopes across the fault scarp which we term fault slopes a scarp of padua chasmata within dione s wispy terrain also has a shallow fault slope although three others that make up palatine chasmata exhibit steeper slopes as predicted we infer that viscous relaxation is the most viable explanation for these shallow fault slopes and we model the potential role of viscous relaxation in creating shallow fault slopes our modeling results support formation of these normal faults with steep dips consistent with deformation experiments followed by their relaxation due to lithospheric heating events related to radionuclide decay the steepest fault slopes in this terrain yield 0 i 0 73 for dione s lithospheric ice which overlaps the dip range predicted from experiments results of this work suggest that viscous relaxation substantially affected fault slopes on tethys rhea and dione by implication these processes may have also affected fault geometries on other icy satellites

a statistical review of the behaviour of concrete face rockfill dams based on case histories the concrete face rockfill dam cfrd has become a preferred dam type but its design remains largely based on past experiences understanding the behaviour of cfrds is critical to the design and s

characterization of debris avalanche deposits in japan abstract seventy one debris avalanche deposits are identified from 52 japanese quaternary volcanoes the structures of these volcanoes are mostly stratovolcanoes and lava domes no avalanche deposit is found in calderas pyroclastic cones or maar volcanoes debris avalanche deposits are found in 18 of all quaternary volcanoes or 25 of quaternary stratovolcanoes and lava domes the ratio rises to 49 when considering only active stratovolcanoes and lava domes at least five debris avalanche deposits have formed since 9th century the maximum height difference of sliding h for each debris avalanche ranges from 200 to 2400 meters and the maximum runout distance of sliding l ranges from 1 6 to 32 km the ratio h l ranges from 0 2 to 0 06 and becomes smaller in larger debris avalanches they are more mobile than landslides in non volcanic areas volume is within a range of 0 03 and 9 km 3 there is no relation between the direction of sliding and the regional horizontal compressional stress axis at the site of a volcano two dimensional computer simulations of avalanches using a simplified physical model are made the maximum velocity is mainly controlled by the length of steep slope