a field experiment for calibrating landslide time of failure prediction functions over the last decades time of failure semi empirical prediction functions have been developed and applied to different landslides with mixed results in this study a field experiment was carried out to calibrate these functions with the simultaneous consideration of small size landslides and landslides that occur on slopes modified by human activities four years of continuous monitoring using an integrated platform consisting of both traditional sensors i e inclinometers piezometers load cells topographic measurement and innovative remote sensing equipment i e terrestrial sar interferometer resulted in the collection of a notably large amount of data several landslides affecting different slopes i e cut slopes cut slopes covered by spritz beton and slopes stabilised by anchored bulkheads were observed as part of the experiment thus facilitating the inference of detailed information for the pre failure behaviour nine landslides were back analysed thus allowing for calibration of the failure prediction functions for different types of slopes from these observations it was found that events occurring on slopes modified by human interventions could be effectively predicted using the voight function if suitable parameters are used as a general remark the landslides that originate from cut slopes in natural terrain behave similar to large landslides reported in the literature similar values of a and while landslides that originate from cut slopes covered by spritz beton and slopes stabilised by anchored bulkheads show values that are significantly lower and a values that are significantly higher than those of landslides on natural terrains

the posidonia shale lower toarcian of sw germany an oxygen depleted ecosystem controlled by sea level and palaeoclimate abstract the lower toarcian posidonia shale is famous for its excellently preserved fossils and its high amount of organic matter up to 16 both quality of preservation and accumulation of organic matter have been explained by permanent anoxic bottom water conditions high resolution geochemical sedimentological and palaeoecological investigations of various sections of the posidonia shale in sw germany however indicate that oxygen availability was variable and ranged from short oxygenated periods to longer term anoxia the benthic macrofauna consists of nine fossil communities and was used in combination with geochemical data to reconstruct a time averaged oxygen curve anoxic conditions prevailed during the deposition of the toarcian black shales they were however punctuated by various short periods weeks to years with oxygenated bottom water conditions sedimentological e g distinctiveness of microlamination siliciclastic content and geochemical parameters e g organic matter content isotopic signatures 18o and 13c molecular redox parameters pristane phytane ratio arylisoprenoids exhibit a remarkable covariation and seem to be controlled by sea level fluctuations maximum oxygen depletion and an extreme negative shift of 13corg values 34 occurred during the early falciferum zone this is explained by the recycling of 12c enriched carbon derived from remineralization of organic matter on and within the substrate during low sea level stand and a highly elevated redox boundary including photic zone anoxia the subsequent transgression permitted enhanced water exchange with the tethyan ocean and caused improvement of living conditions at the end of the falciferum zone other important factors controlling the depositional environment are the overall palaeogeographic situation and climate the early jurassic is the latest period before break up of pangaea and probably was ruled by a strong meridional atmospheric circulation system with pronounced seasonal changes of prevailing trade and monsoon wind systems an estuarine circulation with a positive water balance and surface water with slightly reduced salinity in the summer alternated with an anti estuarine circulation and a negative water balance in the winter during the summer months a stratified water column with anoxic conditions below the halocline developed 18o data indicate low salinity in the surface water during the monsoon influenced summer high productivity was then located in the photic zone and the corresponding isotopically light 18o signal was fixed in the calcareous nannoplankton during the winter months a saline circulation system brought oxygen to the benthic environment favouring temporary benthic colonization especially during times of relative sea level high stand

large boulders along the south eastern ionian coast of sicily storm or tsunami deposits abstract this study investigates the size shape position pre transport setting and long axis orientation of 175 boulders found along the south eastern ionian coast of sicily these megaclasts were deposited by the sea or moved from the same rocky coast to the shore platform and distributed within 60 m of the shoreline most boulders are rectangular to ellipsoidal with sharp broken edges they are calcarenite fragments up to 27 t in mass some of the boulders up to 32 m from shore were observed to have moved after strong winter storms occurring during december 2008 january 2009 whereas the positions of many boulders were unchanged we use wave transport equations jointly with statistical analysis of boulders in order to determine the extreme events geological or meteorological responsible for these singular accumulations using the significant wave height and period of maximum observed storms and historical tsunamis 1693 and 1908 events along the ionian coast of sicily we have estimated the approximate transport distance of boulders by these waves at the coast results show that the largest storm waves were probably responsible for the current distribution of most boulders however since the size and horizontal displacement distance of some boulders scattered randomly along the shoreline at distance 40 m cannot be explained by storm wave action we suggest that they are likely deposited by tsunamis radiocarbon dating performed on three of these anomalous boulders at a distance 40 m from the shoreline gave an age suggesting that two of them were likely deposited by the 1693 or 1908 tsunamis whereas the third was emplaced by a tsunami that occurred after 650 930 a d we show that both wave processes storm and tsunami can deposit boulders we find that the significant difference between storm and tsunami waves is not the breaking wave height but the wave period that influences attenuation and then the flooding distance hence if the boulder transport limit of the largest storm waves in the past at the study area is estimated then it is possible to recognize that the boulders deposited far beyond this limit because of their size and shape were not transported by storm waves but could have been emplaced by waves with longer period such as the tsunamis

why are ancient rocky shores so uncommon the geologic history of rocky shore biotas has been neglected by paleontologists under present conditions of high continentality rocky shores account for more than 33 of the world s coastline they are generally located on shores facing narrow continental shelves where the pattern of global plate tectonics exerts much influence over their regional concentration the highest frequency of rocky shores occurs on islands associated with hot spots island arcs and convergent plate margins associated with subduction rocky shores situated in these settings are subject to recycling so their remains are rare in the stratigraphic record some passive continental margins including those along newly rifted oceans and those with low rates of sedimentation exhibit frequencies of rocky shores as high or higher than those found on many convergent plate margins these have a good chance of being retained in the stratigraphic record for geologically significant periods of time epicontinental flooding reduces the

geological controls on matrix permeability of devonian gas shales in the horn river and liard basins northeastern british columbia canada abstract controls of matrix permeability are investigated for devonian gas shales from the horn river and liard basins in northeastern british columbia canada mineralogy is varied with high carbonate high quartz and moderate quartz carbonate and clay rich strata quartz content varies between 2 and 73 carbonate varies between 1 and 93 and clay varies between 3 and 33 the toc content ranges between 0 3 and 6 wt and porosity varies between about 1 and 7 for horn river basin samples quartz is mainly biogenic in origin derived from radiolarians toc content increases with the quartz content suggesting the toc and quartz both are derived from siliceous phytoplankton a positive relationship between porosity and quartz content is due to the positive relationship between quartz and toc matrix permeability parallel to bedding varies between 7 5e 02 and 7 1e 07 md at an effective stress of 15 mpa variation in permeability is due to a complex combination of factors that includes origin and distribution of minerals pore size distribution and fabric mercury intrusion capillary curves indicate that the higher matrix permeability values 2e 03 md occurs in samples that contain interconnected pore apertures greater than 16 m even when these samples may contain less macropores than low permeability samples the fabric of high permeability samples can be either isotropic or anisotropic however permeability of anisotropic samples is more sensitive to changes in effective stress than isotropic samples more highly anisotropic samples contain moderate amounts of quartz carbonate and in some clay high permeability samples that contain a more balanced ratio between micro meso and macroporosity would not only have faster flow rates but also greater access to sorbed gas within the microporosity compared to samples that lack mesopores several muskwa samples compared to evie and besa river samples contain higher quartz moderate clay and high toc content coupled with high permeability less sensitivity to effective stress and balanced ratios between micro meso and macroporosity would be a lower exploration risk due a greater propensity to fracture the ability to produce and store hydrocarbons due to higher toc contents and greater communication between macropores and micropores in the organic and clay fractions

basal waitemata group lithofacies rapid subsidence in an early miocene interarc basin new zealand the abrupt transition from coastal and shallow shelf sediments to bathyal sediments provides a record of rapid subsidence and deepening of the early miocene waitemata basin basal shallow marine strata kawau subgroup accumulated upon a highly dissected surface that overlies deformed mesozoic metagreywacke the early miocene coast was characterized by an embayed and cliffed shoreline with numerous sea stacks and islands kawau subgroup lithofacies which include pocket beach shallow shelf and base of cliff talus deposits reflect rapidly changing coastline configuration and water depths as the rugged bedrock surface was buried the response to continued rapid subsidence and transgression in waitemata basin was a decrease in the supply of coarse clastic sediment beach gravels were locally displaced to greater water depths by avalanching down steep bedrock slopes the first bathyal turbidite facies which abruptly overlie the shallow water kawau subgroup include locally derived sediment gravity flows commonly ponded by remnant bedrock submarine highs when this local supply of sediment had been exhausted coarse sediment starvation ensued and bathyal muds accumulated with the resumption of sediment supply and gradual burial of submarine bedrock relief submarine fans coalesced and increased in lateral extent subsidence of the waitemata basin to bathyal depths is thought to have occurred in less than a million years from the above hypothesis a general model of sedimentation is proposed

extreme block and boulder transport along a cliffed coastline calicoan island philippines during super typhoon haiyan abstract this paper presents data and analysis for block and boulder transport during super typhoon haiyan along a 4 5 km long low 5 12 m cliffed coastline in calicoan island eastern samar philippines wave runup exceeding 15 2 m elevation above mean sea level drove large limestone clasts with volumes up to 83 m3 up to 280 m inland a few very large clasts with volumes 65 132 m3 were not transported by the waves when combined with recent transport reported in may et al 2015 cox et al 2016 and other literature it is becoming increasingly clear that the largest blocks transported by storms overlie much of the tsunami transport range increasing the difficulty in attributing the transport source without additional evidence comparison of present results with a global database of storm boulder transport shows a mass elevation envelope outside of which no transport is observed initiation of motion criteria were extended to include non rectangular cross sections which significantly reduces inferred velocities particularly for overturning motion these new relations were applied to the largest observed sliding and overturning boulders while considering coefficient uncertainties and resulting velocity uncertainty was large enough that direct inference of wave heights would be problematic estimates of initiation velocities for cliff edge boulders computed using lifting joint bounded relations were unreasonably large when compared to those for sliding and overturning boulders suggesting that processes other than bernoulli lift forces dominated at cliff edges

creep and failure of slopes in clays the accumulated experience on slope stability is reviewed with due consideration to the time dependent behaviour of natural clays prior to failure a consistent picture of the behaviour of both man

graptolites as indicators of regional maturity in lower paleozoic sediments selwyn basin yukon and northwest territories canada variations in reflectance and bireflectance of graptolites and bitumen are documented from lower paleozoic rocks of howard s pass xy zn pb deposit and adjacent portions of the selwyn basin two types of graptolite morphologies are recognized in these rocks a nongranular type comprising blocky and lath shaped varieties and a granular type the nongranular graptolites generally display higher reflectance and bireflectance than granular graptolites bitumen epi impsonite to meso impsonite is common in these rocks and displays a wide range of reflectance and bireflectance values at the howard s pass xy property graptolite reflectance values display a slight increase with depth and anomalously high values 7 46 10 25 are documented in the sulphide rich upper active member in surrounding regions of the selwyn basin remote from howard s pass graptolite reflectance values are lower 3 02 6 26 conodont colour alteration index values reported by others show no detectable variation in the same

wave emplaced coarse debris and megaclasts in ireland and scotland boulder transport in a high energy littoral environment abstract many coastlines of the world particularly those at higher latitudes and those located in tropical cyclone belts are regularly battered by strong storm waves drowning of low lying areas by storm surges and storm floods has been thoroughly recorded however storm deposits at rocky shorelines or on cliffs have been underrepresented in the literature this article presents observations of extraordinary wave deposits along the high wave energy coastlines of western ireland and the northern scottish isles and discusses possible wave event types and time windows of the processes responsible we used archaeological geomorphological and geochronological disciplines to compare our findings with earlier results published for these areas and to contribute to the debate on whether large clasts found well above sea level and or a considerable distance inland were deposited by storms or by tsunamis

inferring total organic carbon and major element geochemical and mineralogical characteristics of shale core from hyperspectral imagery hyperspectral systems that image drill core can capture detail mineralogical information at the millimeter scale and thus have the potential to enable investigators to characterize shale composition and heterogeneity complementing the direct chemical and x ray diffraction analysis of core samples and guiding detailed sampling this method provides insight into petrophysical and geomechanical properties because these properties are significantly correlated to rock composition we tested this approach on a continuous long core from the shale sequence of the horn river group in the horn river basin british columbia sampled at a spacing of 1 m 40 in and analyzed for geochemical composition these data enable the calibration of spectral imagery to rock composition and specifically predict total organic carbon toc and the abundance of sio2 al2o3 k2o and cao we then imaged nine samples from the woodford shale from the permian basin texas for a blind test to assess the predictive models the models were then used to predict toc and geochemical data over detailed imagery of 300 m 984 ft of horn river group shale core and portray their spatial variability downhole as images and profiles in its simplest form hyperspectral imagery can be enhanced to highlight fabric in shale core that otherwise is difficult to visualize because of low brightness in addition we show that spectral imagery of shale can also be processed to either convey mineralogical quartz clay and carbonate or geochemical information the resulting views can readily be used to guide the selection of samples and may provide tools for scaling reservoir properties from individual plugs to reservoir volumes

quantification of slope displacement rates using acoustic emission monitoring in soil slopes developing shear surfaces generate acoustic emission ae the authors have previously proposed the use of active waveguides for monitoring the stability of such slopes active wave

geological and geochemical characterization of the lower cretaceous pearsall formation maverick basin south texas a future shale gas resource as part of an assessment of undiscovered hydrocarbon resources in the northern gulf of mexico onshore mesozoic section the u s geological survey usgs evaluated the lower cretaceous pearsall formation of the maverick basin south texas as a potential shale gas resource wireline logs were used to determine the stratigraphic distribution of the pearsall formation and to select available core and cuttings samples for analytical investigation samples used for this study spanned updip to downdip environments in the maverick basin including several from the current shale gas producing area of the pearsall formation the term shale does not adequately describe any of the pearsall samples evaluated for this study which included argillaceous lime wackestones from more proximal marine depositional environments in maverick county and argillaceous lime mudstones from the distal lower cretaceous shelf edge in western bee county most facies in the pearsall formation were deposited in oxygenated environments as evidenced by the presence of biota preserved as shell fragments and the near absence of sediment laminae which is probably caused by bioturbation organic material is poorly preserved and primarily consists of type iii kerogen terrestrial and type iv kerogen inert solid bitumen with a minor contribution from type ii kerogen marine based on petrographic analysis and pyrolysis carbonate dominates the mineralogy followed by clays and quartz the low abundance and broad size distribution of pyrite are consistent with the presence of oxic conditions during sediment deposition the pearsall formation is in the dry gas window of hydrocarbon generation mean random vitrinite reflectance values ro 1 2 2 2 and contains moderate levels of total organic carbon average 0 86 wt which primarily resides in the inert solid bitumen solid bitumen is interpreted to result from in situ thermal cracking of liquid hydrocarbon generated from original type ii kerogen that was prevented from expulsion and migration by low permeability the temperature of maximum pyrolysis output tmax is a poor predictor of thermal maturity because the pyrolysis s2 peaks from rock eval analysis are ill defined vitrinite reflectance values are consistent with the dry gas window and are the preferred thermal maturity parameter a maverick basin pearsall shale gas assessment unit was defined using political and geologic boundaries to denote its spatial extent and was evaluated following established usgs hydrocarbon assessment methodology the assessment estimated a mean undiscovered technically recoverable natural gas resource of 8 8 tcf of gas and 3 4 and 17 8 tcf of gas at the f95 and f5 fractile confidence levels respectively significant engineering challenges will likely need to be met in determining the correct stimulation and completion combination for the successful future development of undiscovered natural gas resources in the pearsall formation

waves coastal boulder deposits and the importance of the pre transport setting the pre transport environment of a coastal boulder along with its shape size and density determines the height of wave required for it to be transported different forces act on sub aerial boulders as opposed to submerged boulders when struck by a wave boulders derived from joint bounded blocks on shore platforms predominantly experience lift force and require a wave of greater height to be transported than boulders in other environments no one equation is applicable to determine the height of palaeo waves responsible for depositing a field or ridge of imbricated coastal boulders a range of equations and their derivation is presented here which can be applied to the respective pre transport environment of a boulder such an approach is necessary when attempting to reconstruct the frequency and magnitude of past coastal wave hazards and for differentiating between tsunami and storm wave deposited boulder fields

application of organic petrography in north american shale petroleum systems a review abstract organic petrography via incident light microscopy has broad application to shale petroleum systems including delineation of thermal maturity windows and determination of organo facies incident light microscopy allows practitioners the ability to identify various types of organic components and demonstrates that solid bitumen is the dominant organic matter occurring in shale plays of peak oil and gas window thermal maturity whereas oil prone type i ii kerogens have converted to hydrocarbons and are not present high magnification sem observation of an interconnected organic porosity occurring in the solid bitumen of thermally mature shale reservoirs has enabled major advances in our understanding of hydrocarbon migration and storage in shale but suffers from inability to confirm the type of organic matter present herein we review organic petrography applications in the north american shale plays through discussion of incident light photographic examples in the first part of the manuscript we provide basic practical information on the measurement of organic reflectance and outline fluorescence microscopy and other petrographic approaches to the determination of thermal maturity in the second half of the paper we discuss applications of organic petrography and sem in all of the major shale petroleum systems in north america including tight oil plays such as the bakken eagle ford and niobrara and shale gas and condensate plays including the barnett duvernay haynesville bossier marcellus utica and woodford among others our review suggests systematic research employing correlative high resolution imaging techniques and in situ geochemical probing is needed to better document hydrocarbon storage migration and wettability properties of solid bitumen at the pressure and temperature conditions of shale reservoirs

quantification of landslide velocity from active waveguide generated acoustic emission acoustic emission ae has become an established approach to monitor stability of soil slopes however the challenge has been to develop strategies to interpret and quantify deformation behaviour from the measured ae ae monitoring of soil slopes commonly utilizes an active waveguide that is installed in a borehole through the slope and comprises a metal waveguide rod or tube with a granular backfill surround when the host slope deforms the column of granular backfill also deforms and this generates ae that can propagate along the waveguide results from the commissioning of dynamic shear apparatus used to subject full scale active waveguide models to simulated slope movements are presented the results confirm that ae rates generated are proportional to the rate of deformation and the coefficient of proportionality that defines the relationship has been quantified e g 4 4 105 for the angular gravel examined it is demonstrated that slope velocities can be quantified continuously in real time th

response of a landslide to reservoir impoundment in model tests abstract landslides are often induced or activated by reservoir impoundment within the reservoir area in this paper a physical model test was conducted and compared with another published test to investigate the deformation characteristics and failure behavior of a colluvial landslide for conditions with and without reservoir impoundment the laboratory landslide model represented the lower part of a landslide in the three gorges reservoir area a thrust load was applied to represent the upper part of the landslide the thrust load surface deformation pore water pressure and soil pressure were recorded during the experiments the results show that the effect of the reservoir impoundment reduces the time to failure of the landslide and the load causing the failure as expected when water submerged the lower part of the landslide the shearing resistance was reduced the slip surfaces and failure behavior of the landslide under the two conditions are different the entire landslide mass slid along the contact between the colluvium and the bedrock under reservoir impoundment however without a reservoir the landslide slides partially along this contact and multiple slip surfaces through the colluvium

a multidisciplinary approach in determining the maceral kerogen type and mineralogical composition of upper cretaceous eagle ford formation impact on pore development and pore size distribution abstract maceral kerogen or organic matter type and mineralogical composition with the associated porosity of the upper cretaceous eagle ford formation karnes county texas was investigated in karnes county the calcareous mudstone of the eagle ford formation was deposited in an open marine outer shelf to upper slope environment to adequately characterise all components of this mudrock a multidisciplinary approach was implemented to analyse 26 core samples from a single producing well that completed within the eagle ford formation analyses included organic petrology organic geochemistry light and electron microscopy and spectroscopy pore size distribution analyses and x ray diffraction the bitumen reflectance ranges between 1 94 and 2 08 calculated vr o 1 60 1 69 indicating the mudrock is in the condensate rich gas window the toc content ranges between 1 7 and 7 2 with an average of 3 9 mineral composition is dominated in descending order by calcite clay quartz and plagioclase calcite varies between 32 and 87 with an average of 57 porosity measured by helium pycnometry ranges between 3 5 and 10 3 with an average of 7 5 organic petrology coupled with backscattered and field emission scanning electron microscopy indicates matrix bitumen as the most significant contributor to the toc content and porosity matrix bitumen contains significant meso and microporosity and is enhanced by the secondary cracking of the bitumen an increase in bioclastic mostly foraminifera and siliciclastic components correlates with lower toc content due to the lower volume of organic rich matrix peloids fecal pellets are calcareous organic rich and lack terrigenous sediment indicating a zooplankton source pelagic deposition of peloids is interpreted as a primary mechanism of amorphinite deposition which is converted to hydrocarbons and matrix bitumen the mixed siliciclastic calcareous matrix that surrounds the peloids is comprised of matrix bitumen and dispersed organics from land plants vitrinite fusinite and inertodetrinite the siliciclastic component increases in the middle of the eagle ford and marks the boundary maximum flooding surface between the lower tst and upper hst section of the formation the inorganic and organic components suggest a mixed terrigenous and marine source with both inorganic and organic sediments being derived from the proximal ouachita thrust belt and from pelagic organisms within the overlying water column the lower tst eagle ford formation contains more micro and mesopores than the upper hst eagle ford formation due to higher toc content in the lower eagle formation these results illustrate that a multidisciplinary approach is necessary to identify how pore network are distributed within mudrocks and how this distribution is controlled by organic inorganic deposition and hydrocarbon generation processes

effects of soil deformation and saturation on elastic wave velocities in relation to prediction of rain induced landslides abstract the present means of physical landslide early warning systems make use of moisture sensors or slope deformations sensors all such sensors are point sensors and are sensitive to variation of physical parameters in the vicinity of sensors only a large number of sensors are therefore required to cover a wide potential landslide area an idea to observe soil moisture changes and deformations in slope surface by means of elastic wave propagation in soil is proposed in this paper two series of triaxial experiments were conducted as part of this study the first series of experiments explored the behavior of elastic wave propagation with varying soil moisture in another series of experiments soil specimens were subjected to the field stress path experienced by soil elements during rain induced landslides the response of elastic wave velocities during rain induced landslides was envisaged in this test series it was discovered that both shear and compression wave velocities decrease by nearly half when soil saturation was increased from 20 to 80 from the field stress path tests two distinct phases of rain induced slope failures were identified large change in moisture content of soil was observed in the first phase of failure with the soil deformations being very small whereas in the second phase of failure large deformations occurred with very small increase in moisture content of soil both shear and compression wave velocities decreased gradually in the initial phase whereas a rapid decrease was observed in the second phase of failure by observing the change in wave velocities time of failure initiation and post failure strain rate could distinctly be identified such distinct variation of wave velocities during rain induced slope failures can be helpful in designing a robust landslide prediction system

characterization of gas shale pore systems by porosimetry pycnometry surface area and field emission scanning electron microscopy transmission electron microscopy image analyses examples from the barnett woodford haynesville marcellus and doig units the nanometer scaled pore systems of gas shale reservoirs were investigated from the barnett marcellus woodford and haynesville gas shales in the united states and the doig formation of northeastern british columbia canada the purpose of this article is to provide awareness of the nature and variability in pore structures within gas shales and not to provide a representative evaluation on the previously mentioned north american reservoirs to understand the pore system of these rocks the total porosity pore size distribution surface area organic geochemistry mineralogy and image analyses by electron microscopy were performed total porosity from helium pycnometry ranges between 2 5 and 6 6 total organic carbon content ranges between 0 7 and 6 8 wt and vitrinite reflectance measured between 1 45 and 2 37 the gas shales in the united states are clay and quartz rich with the doig formation samples being quartz and carbonate rich and clay poor higher porosity samples have higher values because of a greater abundance of mesopores compared with lower porosity samples with decreasing total porosity micropore volumes relatively increase whereas the sum of mesopores and macropore volumes decrease focused ion beam milling field emission scanning electron microscopy and transmission electron microscopy provide high resolution 5 nm images of pore distribution and geometries image analysis provides a visual appreciation of pore systems in gas shale reservoirs but is not a statistically valid method to evaluate gas shale reservoirs macropores and mesopores are observed as either intergranular porosity or are confined to kerogen rich aggregates and show no preferred orientation or align parallel with the laminae of the shale networks of mesopores are observed to connect with the larger macropores within the kerogen rich aggregates

evolution stages of large deep seated landslides at the front of a subalpine meridional chain maritime alps france abstract studying long term evolution of gravitational slope evolution is a key to understanding deep seated landslide processes this paper deals with three large deep seated landslides dsls at a front of a subalpine meridional chain on the la marbriere slope near the town of grasse alpes maritimes france the geological framework controlling the stability and morphology of the dsls is associated with thick and tamped triassic layers of mudstone with gypsum overlain by highly faulted jurassic limestone gravitational deformation affects the entire slope involving a movement of about 1 1 10 8 m 3 of rock material it creates large disturbances in landscape morphology such as scarps counter slope scarps trenches and other typical gravitational morpho structures geomorphological mapping coupled with deep electrical resistivity tomography ert reveals a strong correlation between these morpho structures and inherited brittle tectonic features this observation relies on spatial and geometrical relations on the surface and at the depth of more than 150 m checked by ert between the most persistent fault and the gravitational morpho structures the specific distribution of the morpho structures on the basis of their morphological typologies and variations in the stage of evolution of three dsls provides an interpretation of their kinematics during the last 400 ka it appears that soft substratums combined with inherited persistent anisotropies are key factors in the development of the dsls indeed outflow of mudstone due to the lithostatic pressure imposed by individual limestone compartments has led to general slope subsidence then a progressive toppling of a rock mass may have led to the catastrophic rock collapse along bedding planes the evolution of the dsls can be divided into three distinct stages represented by three zones a young collapse stage zone 1 a pre collapse stage zone 2 and an old mature stage 400 ka zone 3 as the dsls occur on the same slope and in the same geological context this area offers interesting perspectives for understanding factors controlling the long term gravitational evolution of slopes

global patterns of loss of life from landslides global loss of life from landslides is poorly quantifi ed a global data set of fatalities from nonseismically triggered landslides that resulted in loss of life between a d 2004 and 2010 permits for the fi rst time proper quantifi cation of impacts and spatial distributions in total 2620 fatal landslides were recorded worldwide during the 7 yr period of the study causing a total of 32 322 recorded fatalities these total numbers of landslides and victims are an order of magnitude greater than other data sets have indicated but analysis of the data suggests that it may still slightly underestimate the true human costs the majority of human losses occur in asia especially along the himalayan arc and in china this geographical concentration dominates the annual landslide cycle which peaks in the northern hemisphere summer months finally numbers of fatalities per event show a fat tailed power law distribution with the density of landslides being moderately correlated with the population density on a national basis

reassessment of hydrodynamic equations minimum flow velocity to initiate boulder transport by high energy events storms tsunamis abstract coastal boulders are good evidence of high energy events but the distinction between storm and tsunami boulders remains difficult to identify and mathematical models are still in their preliminary stages in a pioneering contribution nott 1997 2003 developed hydrodynamic equations to assess the minimum wave height required to initiate transport of a coastal boulder by tsunamis or storm surges these equations are widely cited and used but they can be improved in this study nott s equations have been revised 1 the equation for the submerged boulder scenario has been revised by rearranging the lift area of the lift force 2 the subaerial boulder scenario has been reconsidered by rearranging lift area and omitting inappropriate use of inertia force and 3 the joint bounded scenario was revised by balancing force components in the lifting direction and the effect of slope at the pre transport location is tested calculations are performed for four case studies boulders in western and eastern australia data after nott 1997 2003 boulders in southeastern italy data after scicchitano et al 2007 storm boulders in iceland data after etienne and paris 2010 and 2004 tsunami boulders in sumatra data after paris et al 2009 the minimum flow velocity required to initiate the transport of submerged boulders in the revised equation is less than that in nott s equation e g reductions up to 56 for submerged boulders and 65 for joint bounded blocks the minimum flow velocity required to initiate the transport of subaerial boulders from the revised equation also differed in comparison with nott s equation e g 4 22 for boulders detached from a seawall by the 2004 tsunami in sumatra while nott s equation was not applicable to some boulders e g beach rock boulders transported from the nearshore by the 2004 tsunami if we consider a joint bounded scenario for storm boulders in iceland the minimum flow velocity differs 43 to 41 from the results from nott s equation a boulder transport histogram is then introduced to represent the range of flow velocity that satisfies the requirements for initial transport of a boulder in different modes sliding rolling and saltation the boulder transport histogram can be used to predict the possible initial transport mode of a boulder from the flow velocity these theoretical results are compared to field data thus suggesting the initial transport mode of boulders and their pre transport locations the boulder transport histogram would be a valuable tool to reconstruct the magnitude of prehistoric high energy events such as tsunamis or storm surges in terms of flow velocity

tsunami generated boulder ridges in lake tahoe california nevada an array of east trending ridges 1 2 m high and up to 2 km long occurs on the tahoe city shelf a submerged wave cut bench 15 m deep in the northwest sector of the lake the shelf is just north of the amphitheater of the giant subaqueous 10 km 3 mckinney bay landslide which originated on the west wall of lake tahoe images from a submersible camera show that the ridges are composed of loose piles of boulders and cobbles that lie directly on poorly consolidated fine bedded lake beds deposited in an ancestral lake tahoe dredge hauls from landslide distal blocks as well as from the walls of the reentrant of the landslide recovered similar lake sediments the mckinney bay landslide generated strong currents which rearranged previous glacial derived debris into giant ripples creating the boulder ridges the uncollapsed part of the sediment bench including the tahoe city shelf poses a hazard because it may fail again producing a landslide and damaging waves

early detection of first time slope failures using acoustic emission measurements large scale physical modelling early warning systems for slope instability need to alert users of accelerating slope deformation behaviour to enable safety critical decisions to be made this study shows that acoustic emission

hydrocarbon source rock variability within the austin chalk and eagle ford shale upper cretaceous east texas u s a abstract the austin chalk and eagle ford shale are upper cretaceous deposits that extend across texas from the northeast to southwest these formations contain organic carbon enriched mudstones and chalks that were deposited during transgressions of the cretaceous epeiric sea in north america recent workers in petroleum geochemistry have demonstrated that these organic enriched rocks possessed attributes common to oil source rocks the present study of these austin chalk and eagle ford shale rocks is from the perspective of organic petrology and it augments the earlier geochemical work that documented source variability within units of these formations as with the earlier work the results of this study show that both formations contain intervals that are when mature capable of generating commercial quantities of liquid hydrocarbons however this work further revealed that eagle ford rocks not only exhibit greater or ganic carbon contents but also have greater quantities of oil prone kerogen fluorescent amorphinite and exinite when compared with rocks from the austin chalk these source rock differences relate to levels or degrees of organic preservation dysaerobic to oxic depositional settings seem to be more characteristic of the austin chalk than of the eagle ford shale such oxic environments do not consistently favor the preservation of organic matter usually well preserved kerogen forms under more anoxic conditions such as those that occurred during deposition of some eagle ford units these anoxic conditions suggest that the geographically more extensive eagle ford shale is a more important source for oil than is the austin chalk

experimental investigation on progressive deformation of soil slope using acoustic emission monitoring abstract the deformation process of soil slopes observed during a landslide can have progressive characteristics which can be quantified through acoustic emission ae monitoring a model test is designed based on the geological model of a translational landslide and experiments are conducted to reproduce the three stage deformation process of a soil slope the deformation process of progressive landslides is described using equations and an entire loading process is realized using a programmable logic controller plc the maximum velocity of a sliding body is measured to be approximately 6 mm s with the final displacement exceeding 210 mm the ae deformation and mechanical measurements of the entire process are compared to comprehensively evaluate the evolution behavior of progressive soil landslides the experiments demonstrate that ae rates can linearly quantify slope velocity as well as help quantify slope acceleration a copper tube and an aluminum tube are compared as different waveguides and the quantitative relationship between the ae and deformation obtained by the active copper waveguide is found to be more distinct the experiments also show that the acceleration of a slope can be effectively used as a discriminant index of progressive landslides which has the potential to be applied in field monitoring

organic matter hosted pore system marcellus formation devonian pennsylvania the marcellus formation of pennsylvania represents an outstanding example of an organic matter om hosted pore system most pores detectable by field emission scanning electron microscopy fe sem are associated with om instead of mineral matrix in the two wells studied here total organic carbon toc content is a stronger control on om hosted porosity than is thermal maturity the two study wells span a maturity from late wet gas vitrinite reflectance ro 1 0 to dry gas ro 2 1 samples with a toc less than 5 5 wt display a positive correlation between toc and porosity but samples with a toc greater than 5 5 wt display little or no increase in porosity with a further increasing toc in a subset of samples 14 across a range of toc 2 3 13 6 wt the pore volume detectable by fe sem is a small fraction of total porosity ranging from 2 to 32 of the helium porosity importantly the fe sem visible porosity in om decreases significantly with increasing toc diminishing from 30 of om volume to less than 1 of om volume across the range of toc the morphology and size of om hosted pores also vary systematically with toc the interpretation of this anticorrelation between om content and sem visible pores remains uncertain samples with the lowest om porosity higher toc may represent gas expulsion pore collapse that was more complete as a consequence of greater om connectivity and framework compaction whereas samples with higher om porosity lower toc correspond to rigid mineral frameworks that inhibited compactional expulsion of methane filled bubbles alternatively higher toc samples may contain om low initial hydrogen index relatively unreactive that is less prone to development of fe sem detectable pores in this interpretation om type controlled by sequence stratigraphic position is a factor in determining pore size distribution

testing the hypothesis for tsunami boulder deposition from suspension tsunamis are known to deposit boulders but it is not clear if they are transported solely as bed load or whether suspended load can be involved it has been reported that numerous individual boulders and imbricated boulder stacks at elevations above normal storm tide levels along the new south wales nsw coast of se australia have been deposited out of suspension by tsunamis the nsw coast therefore provides an important natural laboratory to test the hypothesis that tsunamis can deposit large boulders from suspension using standard hydrodynamic equations to formulate the relationship between boulder transport and flow depth we provide a test of the suspension hypothesis we show that the tsunami flow depths required for deposition from suspension are most probably physically unrealistic the nsw boulders are therefore not indicative of deposition from suspension and an alternative explanation must be sought for their mechanism of emplacement this analysis has important implications for the emerging sub branch of tsunami boulder geology

megaclasts proposed revised nomenclature at the coarse end of the udden wentworth grain size scale for sedimentary particles abstract the expanded udden wentworth u w grain size scale is an important tool for classifying the size of sedimentary particles however some of the existing terminology at the coarse end of the scale is problematic in particular the current terms block and slab are used to define size ranges despite having recognized shape connotations and simultaneous application in particle form shape diagrams the dual usage such of terminology is undesirable and may have contributed to the lack of strict adherence by the earth science community to the upper end of the u w scale resulting in part in the plethora of alternative expressions that have appeared in recent years for describing very large clasts our solution to this conundrum is to abandon shape related terms and replace them with an incremental system based on the prefixes meso and macro to classify very large boulder size ranges in this way both size and shape classification of very coarse sediments can be accomplished satisfactorily without unnecessary overlap or confusion in nomenclature the term megaclast is appropriate to remain as a universal descriptor for all clasts greater than boulder size i e b axis 4 1 m as previously defined

development of progressive landslide failure in cohesive materials the development of progressive failure in slopes is a poorly understood process and relatively few advances in terms of the mechanics of the development of failure have been made since 1967 however advances in the understanding of the development of fractures in brittle materials provide new insights into landslide mechanics in addition the link between the deformation mechanism and movement type allows interpretation of displacement records to determine the mechanisms acting within a slope this paper utilizes these insights into deformation processes combined with reinflation stress path triaxial experiments to propose a new model for the development of a progressive first time failure within a slope this model is able to explain the development of failure when the factor of safety is greater than unity the existence of saito linearity a linear trend when the reciprocal of velocity prior to failure is plotted against time during tertiary creep and the development of failures during periods of apparently increasing normal effective stress

pore structure wettability and tracer migration in four leading shale formations in the middle yangtze platform china abstract deposited in different sedimentary settings four leading shale formations late ordovician wufeng early silurian longmaxi late permian dalong and early jurassic dongyuemiao shales are currently the most promising zones for shale gas development in the middle yangtze platform of south china based on complementary tests low pressure gas physisorption mercury injection capillary pressure micp contact angle measurement fluid imbibition into initially dry shale and tracer diffusion into initially fluid saturated shale followed by tracer mapping with laser ablation inductively coupled plasma mass spectrometry la icp ms this work investigates their pore structure both geometry and connectivity and wettability characteristics as well as the coupled effects of these characteristics on fluid flow and tracer migration pores

research on the displacement response ratio of groundwater dynamic augment and its application in evaluation of the slope stability on the basis of systematic analysis on the motivation and mechanism of displacement and destabilization of the water induced landslides this paper completes a study on the relationship between groundwater dynamic effect laws and displacement response characteristics in the process of the colluvial landslide stability evolution it is found that the displacement and destabilization of landslide are directly controlled by the underground water level variation and also there exists one to one corresponding relation between the deformation of landslide and the groundwater level variation on the basis of the results above the underground water level increment and the corresponding deformation variation are taken to be as the dynamic load parameter of landslide and the dynamic incremental displacement response parameter respectively then the displacement dynamic appraisal parameter and prediction model of the groundwater dynamic incremental displacement response ratio are determined in term of the basic principle of elastic plastic mechanics in this paper meanwhile taking the typical colluvial landslide in the three gorges reservoir area xintan landslide as an example the values and changing rule of the groundwater dynamic incremental displacement response ratio parameter of the a3 and b3 monitoring points on this landslide are obtained by means of the groundwater dynamic incremental displacement response ratio prediction model finding that the change rule of the dynamic incremental displacement response ratio time curve is consistent basically with the dynamic stability evolutional law of the actual slope the research results show that the groundwater dynamic incremental displacement response ratio prediction model can be used to forecast the kinetics of displacement for this slope and this method has widely theory and extensive practicality

characterizing the shale gas resource potential of devonian mississippian strata in the western canada sedimentary basin application of an integrated formation evaluation devonian mississippian strata in the northwestern region of the western canada sedimentary basin wcsb were investigated for shale gas potential in the subsurface thermally mature strata of the besa river horn river muskwa and fort simpson formations attain thicknesses of more than 1 km 0 6 mi encompassing an area of approximately 125 000 km2 48 300 mi2 and represent an enormous potential gas resource total gas capacity estimates range between 60 and 600 bcf section of particular exploration interest are shales and mudrocks of the horn river formation including the laterally equivalent lower besa river mudrocks muskwa formation and upper besa river formation which yield total organic carbon toc contents of up to 5 7 wt fort simpson shales seldom have toc contents above 1 wt horn river and muskwa formations have excellent shale gas potential in a region between longitudes 122w and 123w and latitudes 59n and 60n national topographic system nts 94o08 to 94o15 in this area which covers an areal extent of 6250 km2 2404 mi2 average toc contents are higher 3 wt as determined by wire line log calibrations and have a stratal thickness of more than 200 m 656 ft gas capacities are estimated to be between 100 and 240 bcf section and possibly greater than 400 tcf gas in place a substantial percentage of the gas capacity is free gas caused by high reservoir temperatures and pressures muskwa shales have adsorbed gas capacities ranging between 0 3 and 0 5 cm3 g 9 6 16 scf t at reservoir temperatures of 60 80c 140 176f whereas besa river mudrocks and shales have low adsorbed gas capacities of less than 0 01 cm3 g 0 32 scf t liard basin region because reservoir temperatures exceed 130c 266f potential free gas capacities range from 1 2 to 9 5 cm3 g 38 4 to 304 scf t when total pore volumes 0 4 6 9 are saturated with gas the mineralogy has a major influence on total gas capacity carbonate rich samples indicative of adjacent carbonate platform and embayment successions commonly have lower organic carbon content and porosity and corresponding lower gas capacity 1 toc and 1 porosity seaward of the carbonate slave point edge muskwa and lower besa river mudrocks can be both silica and toc rich up to 92 quartz and 5 wt toc and most favorable for shale gas reservoir exploration because of possible fracture enhancement of the brittle organic and siliceous rich facies however an inverse relation between silica and porosity in some regions implies that zones with the best propensity for fracture completion may not provide optimal gas capacity and a balance between favorable reservoir characteristics needs to be sought

two and three dimensional numerical analysis of the progressive failure that occurred in an excavation induced landslide abstract a finite element approach in which an elasto viscoplastic strain softening model is incorporated is used to analyse a landslide that occurred after deep excavations had been carried out for the construction of several buildings at the toe of the slope the soils involved in the landslide were characterized by a pronounced strain softening behaviour with the shear strength that abruptly reduces as plastic strain increases as is well known a progressive failure may be triggered in these soils by excavation and it can cause the collapse of the slope after some time the numerical approach used in the present study allows this phenomenon to be properly simulated results from both two dimensional 2d and three dimensional 3d analyses of the landslide are performed the results from these analyses confirm the occurrence of a progressive failure within the slope however the 2d analysis does not completely account for the failure process that occurred because of the 3d nature of this process that propagated in both upward and lateral directions a more realistic simulation of the slope failure is achieved by performing a 3d analysis

organic geochemistry distribution and hydrocarbon potential of source rocks in the paleocene lishui sag east china sea shelf basin abstract the lishui sag one of the most promising hydrocarbon exploration areas in the east china sea shelf basin has had no major breakthroughs after its exploration and development therefore it is crucial to carry out a comprehensive assessment of this basin to illustrate the potential and distribution of source rocks in the lishui sag based on organic petrographic examinations rock eval pyrolysis gas chromatography gc and gas chromatography mass spectrometry gc ms analysis the organic geochemical characteristics and paleoenvironment of the source rocks were investigated the results imply that the kerogen type of the source rocks in the lishui sag is dominated by type iii with a small amount of type ii kerogen biomarkers show that the source rocks are characterized by a mixed origin of organic matter in a transitional environment the lower mingyuefeng e1ml lower lingfeng e1ll and yueguifeng e1y formations show higher inputs of aquatic organic matter the base limits of the total organic carbon toc values of effective source rocks were determined to be 0 9 wt in the e1m formation 1 0 wt in the e1l formation and 0 7 wt in the e1y formation based on an artificial neural network ann model and the log r method the distribution of effective source rocks in the lishui sag was illustrated source rocks in the e1ml and lingfeng e1l formations can be expected to generate mixed liquid hydrocarbons while samples from e1y formation are oil prone source rocks with normal oil and light oil potentials additionally the post mature source rocks of the e1y formation may be the origin of natural gas upon full consideration of the potential and distribution of source rocks the north part of the lingfeng uplift is the most favorable exploration zone

evaluation of tsunami flooding using geomorphologic evidence abstract whatever the generating mechanism of a tsunami may be this event can discharge destructive energy along coastal areas and produce widespread inundation the presence of large boulders along rocky coasts could be a useful indicator to understand the extent of the impact of past tsunami floods a detailed study of the deposited boulder features size shape and rock density and their initial position prior to the transport is extremely important when reconstructing the possible morphodynamic scenario s applying the appropriate equations is important when aiming to assess the maximum extent of flooding the integration of morphological and hydrodynamic data allows for an estimation of the water level during the tsunami event responsible for boulder transport moreover it is possible to calculate how far the impacting wave flooded inland this is a function of the wave parameters and of the degree of roughness of the flooded terrain that is expressed by the manning number to evaluate its probable average value experimental data computer simulations and post tsunami surveys have been performed in two sectors of the southern apulia coastline characterised by the presence of tsunami boulder fields and or ridges the surveys in each site have allowed for the calculation of the boulder sizes the estimation of their pre transport location and the extent of inland flooding data have been processed using a geographic information system gis as a result a flooding map useful in planning future possible actions for coastal area use has been produced

nanoscale pore structure and fractal characteristics of a marine continental transitional shale a case study from the lower permian shanxi shale in the southeastern ordos basin china abstract shale samples collected from seven wells in the southeastern ordos basin were tested to investigate quantitatively the pore structure and fractal characteristics of the lower permian shanxi shale which was deposited in a marine continental transitional hereinafter referred to as the transitional environment low pressure nitrogen adsorption data show that the shanxi shale exhibits considerably much lower surface area sa and pore volume pv in the range of 0 6 1 3 m 2 g and 0 25 0 9 ml 100 g respectively type iii kerogen abundant in the transitional shanxi shale were observed to be poorly developed in the organic pores in spite of being highly mature which resulted in a small contribution of organic matter om to the sa and pv instead i s illite smectite mixed clay together with illite jointly contributed mostly to the sa and pv as a result of the large amount of inter layer pores associated with them which were evident in broad ion beam bib imaging and statistical analysis additionally the shanxi shale has fractal geometries of both pore surface and pore structure with the pore surface fractal dimension d1 ranging from 2 16 to 2 42 and the pore structure fractal dimension d2 ranging from 2 49 to 2 68 respectively the d1 values denote a pore surface irregularity increase with an increase in i s and illite content attributed to their more irregular pore surface compared with other mineralogical compositions and om the fractal dimension d2 characterizing the pore structure complexity is closely related to the pore arrangement and connectivity and i s and illite decrease the d2 when their contents increase due to the incremental ordering degree and connectivity of i s or illite hosted pores meanwhile other shale constituents including kaolinite chlorite and om that possess few pores can significantly increase the pore structure complexity by way of pore blocking

from landslide susceptibility to landslide frequency a territory wide study in hong kong abstract rain induced shallow landslide is the major type of landslide that happens on natural terrain in hong kong due to its high seasonal rainfall and deep weathering soil profile the geotechnical engineering office has been in a leading role to steer the risk management of natural terrain landslides in hong kong recently the territory wide rainfall based landslide susceptibility model in terms of landslide density per year has been developed to predict the number of natural terrain landslides that may occur in an anticipated rainfall event subsequently the storm based landslide density has been transformed to the annual landslide frequency to compile the territory wide landslide frequency map by incorporating the mean annual frequency of occurrence of different probable rainfall scenarios the annual rainfall frequency of a particular rainfall scenario is derived from its return period determined based on the abundant real time rainfall data at a five minute interval from 110 automatic raingauges across hong kong at an average density of 10 km2 gauge the transformation is discussed in this paper together with the evaluation of the performance of the landslide frequency map in addition the potential applications of the map in hong kong and the pitfalls of the common evaluation methods including the receiver operating characteristic curve and the success rate curve are highlighted

suction and rate dependent behaviour of a shear zone soil from a landslide in a gently inclined mudstone sandstone sequence in the sichuan basin china abstract bedding controlled landslides in alternated mudstone and sandstone beds in cataclinal slopes are common in the sichuan basin and in the three gorges area in china they are characterised by very gentle dip angles of the beds

bedrock sculpturing by tsunami south coast new south wales australia bedrock sculpturing resulting in s forms is associated with catastrophic flooding in near and subglacial environments produced by flow velocities approximating 10 m s 1 these velocities can also be produced by extreme tsunami generated by submarine landslides or comet impacts with oceans repetitive tsunami events during the late holocene have overwashed headlands along the new south wales south coast and produced two suites of bedrock sculptured terrain at the smaller scale s forms similar to muschelbruche v shaped grooves and sichelwannen have developed on upslopes while broad potholes flutes and transverse troughs have formed on headland crests cavitation features consisting of sinuous grooves impact marks drill holes and cavettos appear more ubiquitously at the larger scale stripped ramps large potholes cascade channels and canyon like features have been generated six flow phenomena mach stem waves jetting vortex impingement horseshoe vortices helical flow and multiple vor

sedimentologic and geomorphologic tsunami imprints worldwide a review abstract tsunami events with extreme effects on sedimentary transport or considerable alterations of the coastal configuration are rather rare regarding human history but considering geological timescales they occur frequently at least 100 megatsunami in different parts of the world have been recorded in the past 2000 years but presumably far more have failed to be noticed during historical times and are not mentioned either in written or oral ancient records therefore the topic of paleotsunami requires inevitable sedimentological and geomorphological research however field research concerning paleotsunami is astonishingly rare within the scientific approach and only 5 of the existing tsunami literature is related to this subject future efforts in paleotsunami research should focus on the geological evidence of these mega events to clarify their contribution to coastal forming processes this paper reviews the state of the art knowledge of sedimentologic and geomorphic imprints of tsunami along the world s coastlines in order to highlight the need for more detailed studies of paleotsunami depositional and geomorphological traces

correlation of acoustic emissions with patterns of movement in an extremely slow moving landslide at peace river alberta canada the peace river region alberta canada has experienced extensive landslide activity since deglaciation shear zones within weak lacustrine silt and clay layers typically experience continuous cre

landslide damage incurred to buildings a case study of shenzhen landslide abstract construction solid waste csw landslides are always characterized by high mobility and thus pose much danger to surrounding residents and buildings in this study a back in situ analysis of the catastrophic csw landslide occurred in shenzhen in december 2015 is presented in which the motion accumulation evolution process of the landslide and damage to structures are reproduced and reasonable agreement between the simulation and actual conditions is obtained in landslide process modeling a depth averaged model that can undergo dilation and contraction during deformation is adopted to simulate the behavior of the landslide assuming different conditions of initial solid volume fraction the results show that a small initial solid volume fraction of a water laden landslide undergoes small resistance caused by dilatancy on the basis of landslide process analysis the fluid solid interaction is decoupled and considered to be a one way action of the landslide on structures which is reflected in the form of impact force structural response is evaluated by 3d finite element modeling the failure process presents a type of plastic hinge formation at the beam column connection positions followed by local destruction of the impacted columns and final structural failure is the cumulative result of this damage over time this integrated approach could be implemented in quantitative risk assessment procedures pertaining to landslides

stability analysis and reinforcement evaluation of high steep rock slope by microseismic monitoring abstract the stability of excavated high steep rock slopes is most significant in the long term safety of large scale hydropower projects dagangshan rock slope had an unloading fractured zone xl 316 and a fault f231 during excavation which resulted in a high risk of slope instability anti shear tunnels were constructed for enhancing the overall shear resistance and reinforcing the slope at six different elevations the microseismic technique was employed to investigate microseismic activities during excavation and after reinforcement an integrated method of microseismic energy density and the magnitude frequency relation based on microseismic monitoring was proposed to analyse the stability and reinforcement effect of the slope during excavation a large number of microseismic events took place with few low magnitude events and numerous high magnitude events the aggravated damage occurred in the major discontinuities during excavation the number of low magnitude microseismic events increased after reinforcement and the b value obviously increased which means the slope stability was substantially enhanced microseismic activities were evidently reduced and the accumulated microseismic energy increased slowly the stresses were transferred towards the edge of the anti shear tunnel and a small number of low energy events occurred the targeted reinforcement has served well for its purpose and improves the mechanical performance of the discontinuities the application of the proposed method was verified by 3d rfpa centrifuge software the proposed method can be considered as an effective way to evaluate the reinforcement effect and stability of high steep rock slopes

petroleum potential of serpentine plugs and associated rocks central and south texas abstract during deposition of the upper cretaceous austin chalk and taylor marl serpentine plugs formed by submarine volcanic activity along major fault zones in the ancient gulf of mexico after eruption palagonite tuff mounds formed by the hydration of basaltic glass localized deposition of shoal water carbonates on topographic highs the serpentine plugs occur along an arcuate belt extending approximately 250 mi 400 km from milam county southwestward to zavala county texas hydrocarbon traps in and around serpentine plugs have yielded approximately 47 million bbl of oil and significant quantities of natural gas from altered volcanic tuff and associated shoal water carbonates shallower production is from overlying sedimentary rocks structurally influenced by volcanic plugs entrapment of hydrocarbons occurs as 1 stratigraphic traps within porous zones of carbonate units 2 stratigraphic traps within porous volcanic tuff serpentine 3 structural traps within overlying sands and 4 traps within high porosity fracture zones exploration for plugs should be concentrated along existing fault zones by either magnetic or seismic surveys analysis of the plugs suggests that there are at least 3 distinctive groups 1 a southern group characterized by well developed and productive marginal sands 2 a middle group characterized by hydrocarbon saturated biocalcarenite and reworked volcaniclastic facies and 3 a northern group in which the dominant hydrocarbon saturation is in the volcanics themselves each of these groups appears to reflect a somewhat different geologic history end of article last page 504

the potential hazard from tsunami and seiche waves generated by large earthquakes within lake tahoe california nevada we investigate the potential of local earthquakes to generate tsunamis and seiches within lake tahoe we calculated the long wavelength oscillations generated by 3 hypothetical m w 7 earthquake scenarios for faults with normal slip directly under and outside the lake basin the scenarios involving fault slip under the lake are the north tahoe incline village and west tahoe dollar point scenarios the genoa scenario involves a fault that crops out 10 km east of the lake faulting beneath the lake generates a tsunami followed by a seiche that continues for hours with waves as large as 3 to 10 m the seiche potentially threatens low lying lakeside communities and lifelines we also compare the spectral characteristics of synthetic tide gauge records with wind swell observations the fundamental mode calculated for a seiche is consistent with the wind swell observations

analysis of acoustic emission patterns for monitoring of rock slope deformation mechanisms acoustic emission ae is generated in soil and rock materials by rearrangement of particles during displacement or increasing damage in the microstructure preceding a collapse therefore ae is appropriate for estimation of slope degradation to overcome the high attenuation that characterise geological materials and thus to be able to monitor ae activity a system that makes use of a waveguide to transmit ae waves from a deforming zone to a piezoelectric transducer was developed the system quantifies acoustic activity as ring down count rdc rates in soil applications rdc rates have been correlated with the rate of deformation whereas the recent application to rock slopes requires new interpretation strategies in order to develop new strategies the system was installed at two rock slope trial sites in italy and austria rdc rates from these sites which have been measured over 5 and 1 5 years respectively are analysed and clear and recurring trends are identified the comparison of ae trends with response from a series of traditional instruments available at the sites allows correlation with changes in external slope loading and internal stress changes ae signatures from the large rock slope in italy have been identified as generated in response to variations in the groundwater level and snow loading at the slope in austria ae signatures include the detachment of small boulders from the slope surface caused by the succession of freeze thaw cycles during winter time the work reported in this paper is contributing to the development of ae monitoring and interpretation strategies for rock slopes the longer term aim is to identify approaching failures and derive rules for setting thresholds that can be used to give warning of rock slope failures in time to enable action to be taken

do all fractions of organic matter contribute equally in shale porosity a case study from upper ordovician utica shale southern quebec canada abstract in many unconventional hydrocarbon systems organic matter om substantially contributes to total porosity of the rock that led to a positive correlation between total organic carbon toc and porosity while organic porosity is an important reservoir property of unconventional hydrocarbon systems toc of these rocks consists of different macerals or petrographic fractions these toc fractions can be geochemically divided and quantified by the revised extended slow heating esh rock eval analysis this study discusses the contribution of different fractions of om on porosity variation in the mature to overmature utica shale in southern quebec using esh rock eval analysis helium pycnometery scanning electron microscopy sem and x ray diffraction xrd mineralogy selected samples from three wells at depths of 400 700 and 2000 m covering a range of thermal maturity from late peak oil window vroeqv 1 to dry gas zone vroeqv 2 1 were analyzed in this study the predominant om constituents are solid bitumen chitinozoans and minor graptolites with mean toc of 1 1 0 4 wt the mean porosity for oil and gas window samples decreases with depth from 3 9 0 9 to 2 6 0 5 respectively the sem images reveal that organic porosity is limited to pores developed in solid bitumen while regardless of thermal maturity chitinozoans have a non porous structure throughout the oil to dry gas window this observation suggests that the impact of thermal maturity on porosity is different for different om fractions i e macerals leading to different contribution of om fractions to total porosity the latter conclusion is further supported by the improved correlation observed between the solid bitumen fraction and porosity compared to toc porosity correlation for oil window samples our entire data set suggests that om i e bitumen fraction especially in the dry gas window is not the major controlling factor on the total porosity in the utica shale whereas intergranular porosity has the dominant control on total porosity this observation suggests that the hydrocarbon storage potential may largely reside in inorganic pores rather than organic pores in the analyzed intervals of the utica shale the decrease in total porosity observed from shallower samples i e oil window to deeper samples i e dry gas window also suggests that intergranular porosity is the dominant porosity component which decreases with burial

geological evaluation of halfway doig montney hybrid gas shale tight gas reservoir northeastern british columbia abstract evaluation of the reservoir quality of the triassic halfway montney doig hybrid gas shale tight gas reservoir in the groundbirch field in northeastern british colombia requires an integration of unconventional and conventional methodologies reservoir evaluation includes reservoir thickness and structure total porosity toc content organic maturity pore size distribution micro to macro pore size fractions surface area mineralogy and pulse decay permeability quartz 10 74 carbonate 13 73 and feldspar 0 42 dominate the mineralogy of all formations with illite 0 32 being locally important the t max values range between 443 and 478 c placing the reservoirs beyond the oil window pore size distribution by low pressure gas adsorption analysis identifies a large variation between the contributions from the micro meso and macro pore size fractions matrix permeabilities range between 1 0e 3 and 6 5e 7 md at an effective stress between 2400 and 3300 psi 16 5 22 8 mpa changes in depositional environments and diagenetic processes manifest as differences in lithology and mineralogy within the montney and doig reservoirs which subsequently affect the fabric texture and pore size distribution fabric texture and pore size distribution contribute to the variation in the permeability and the proportions of free to sorbed gas within the reservoir quartz rich coarser grained intervals upper portions of doig c b and halfway formation have lower surface area greater porosities and a higher volume of macropores compared to the carbonate and clay rich finer grained intervals doig a permeabilities do not vary according to lithology with higher permeabilities found within both fine grained doig a and coarser grained halfway formation units permeability is controlled by pore size distribution higher permeability samples contain a balanced ratio between micro meso and macro porosity the finer grained intervals have higher sorbed gas capacity due to higher surface areas because of the higher volumes of finer mesopores and micropores than the coarser grained units however porosity and permeability are low in some parts of the doig a and fracture stimulation is necessary to achieve economic flow rates

methane adsorption characteristics of overmature lower cambrian shales of deepwater shelf facies in southwest china abstract the lower cambrian shales of deepwater shelf facies comprise an important part of the marine black shales in southern china in this study twenty four lower cambrian shale samples from southwest china were subjected to analysis of geochemistry pore structure and methane adsorption capacity the samples have total organic carbon toc contents ranging from 0 25 to 11 3 and equivalent vitrinite reflectance eqvro values in the range of 2 51 4 23 specific surface areas determined from n2 adsorption at 77 4 k and specific micropore volumes from co2 adsorption at 273 15 k are in the range of 3 0 38 6 m2 g rock and 2 5 11 4 cm3 kg rock respectively and both of them have positive relationships with toc values the langmuir volumes of these samples at 60 c range from 0 47 cm3 g rock to 5 96 cm3 g rock and are positively correlated with toc values which on the one hand confirms the toc control on methane adsorption capacity and on the other hand also suggests a weak control of thermal maturity on methane adsorption capacity at overmature stages although both specific surface area and specific micropore volume are positively correlated with methane adsorption capacity the latter seems to have a stronger effect and the specific micropore volume determined from subcritical co2 adsorption may be considered as a proxy for the volume of adsorbed methane in dry shales for the extrapolation of measured methane excess adsorption isotherms to geological conditions the use of a constant or varying langmuir volume makes no significant difference with respect to the methane storage capacity of shales when the density of the adsorbed methane is allowed to change with temperature however the absolute methane adsorption quantity at subsurface is obviously dependent on the use of a constant or varying langmuir volume which subsequently affects the estimation of the relative percentages of adsorbed and free methane

a novel approach for determining landslide pushing force based on landslide pile interactions abstract the distribution of soil pressure in landslides above anti slide piles is a key factor in their design the paper describes the evolution of stresses near soil piles by testing a physical scale model during progressive loading displacement monitoring data on the surface of the landslide during loading discloses four main evolutionary stages the initial stage of deformation the uniform deformation stage the accelerating deformation stage and the damage stage during initial deformation the vertical distribution of soil pressure above anti slide piles is sigmoidal with the highest pressures occurring in the middle and upper parts of the slide mass next during the uniform deformation stage the soil pressure begins to assume a parabolic shape in a vertical profile and this shape is fully realized during subsequent accelerating deformation finally during the damage stage the soil pressure relaxes to low values near the center of the slide mass effectively inverting the parabola thus the distribution of soil pressure above anti slide piles changes in a complex manner during deformation and these effects must be accommodated in the analysis and design of anti slide piles

boulder ridges on the aran islands ireland recent movements caused by storm waves not tsunamis abstractireland s aran islands are an excellent place to test whether coastal boulder deposits including individual rocks weighing several tens of tonnes near sea level and clasts weighing several tonnes transported at tens of meters above sea level require a tsunami for emplacement or whether storm waves can do this work elongate deposits of cobbles boulders and megagravel are strung along the atlantic coasts of the aran islands no tsunamis have affected this region in recent centuries so if these deposits are forming or migrating at the present time they must be storm activated we find a diverse range of evidence for recent ridge activity first shells of hiatella arctica subtidal rock boring bivalves preserved in life position within ridge boulders yield radiocarbon ages from 200 ad to modern post 1950 ad second recent motion is attested to by eyewitness accounts that pin the movement of several individual 40 80 t blocks to a specific 1991 storm and by repeat photography over the last fe

storm rogue wave or tsunami origin for megaclast deposits in western ireland and north island new zealand the origins of boulderite deposits are investigated with reference to the present day foreshore of annagh head nw ireland and the lower miocene matheson formation new zealand to resolve disputes on their origin and to contrast and compare the deposits of tsunamis and storms field data indicate that the matheson formation which contains boulders in excess of 140 tonnes was produced by a 12 to 13 m high tsunami with a period in the order of 1 h the origin of the boulders at annagh head which exceed 50 tonnes is disputed we combine oceanographic historical and field data to argue that this is a cliff top storm deposit ctsd a numerical model for ctsds is developed which indicates that boulder shape in addition to density and dimensions should be taken into account when applying hydrodynamic equations to such deposits the model also predicts that the ne atlantic storms are capable of producing boulderites that when size alone is considered cannot be distinguished from tsunamites we review the characteristics that identify the origins of these two deposits

wettability and connectivity of overmature shales in the fuling gas field sichuan basin china the fuling gas field in sichuan basin china has produced greater than 1 5 1010 m3 0 53 tcf of natural gas from overmature upper ordovician wufeng and lower silurian longmaxi shales to systemically investigate the characteristics of wettability and connectivity and to understand the underlying causes of production behavior we study five samples of wufeng and longmaxi shales with different total organic carbon contents and mineral compositions complementary approaches include mercury intrusion capillary pressure micp contact angle measurement spontaneous imbibition and saturated diffusion and tracer both nonsorbing and sorbing migration mapped via laser ablation inductively coupled plasma mass spectrometry according to measured contact angles and imbibition tests conducted on aqueous deionized water and brine and oleic n decane phases wufeng and longmaxi shales are strongly oil wet and moderately strong water wet the lower boundary of estimated permeability obtained from n decane imbibition can reach 137 nd which is higher than the geometric mean permeability derived from the micp method 5 5 68 8 nd effective diffusion coefficients of the wufeng and longmaxi shales are in the range of 10 13 m2 s 1 1 10 12 ft2 s tests of imbibition and saturated diffusion using tracer containing brine show that concentrations of nanometer sized tracers decrease rapidly a factor of 10 over a migration distance of a few millimeters from the sample edge suggesting the presence of poorly edge connected water wet pores sparsely connected hydrophilic pores mixed wettability and highly restricted pathways collectively contribute to the limited migration of nano sized tracers which probably results in the production behavior of initial steep decline and low overall recovery in the fuling gas field

the organic matter distribution and methane capacity of the lower cretaceous strata of northeastern british columbia canada abstract the methane sorption capacity of a succession of sandstone siltstone shale and coal from the lower cretaceous fort st john group of northeastern british columbia was investigated average organic matter om content for all formations is 2 3 wt with a minimum of 0 6 wt and maximum of 10 1 wt the methane sorption capacity ranges between 0 19 and 2 74 cm3 g at 6 mpa and at 30 c total gas capacity free and sorbed gas ranges between 2 2 and 16 6 cm3 g at 6 mpa micropore volumes range between 0 43 and 1 69 cm3 100 g a positive correlation exists between the om content micropore volume and the methane capacity of shales shales with high methane capacities have either high contents of inertodetrinite or vitrinite moisture content shows a positive relationship with om content micropore volume and methane capacity the negative relationship between moisture and surface area derived from n2 adsorption suggests the moisture is located within the microporosity of the om and also explains the positive relationship between methane capacity and moisture the high inertodetrinite and vitrinite contents correlate with sea level regressions that delivered terrestrial om from coastal plains located south of the study area into the basin

geochemical evolution of organic rich shales with increasing maturity a stxm and tem study of the posidonia shale lower toarcian northern germany hydrocarbon generation and retention processes occurring within gas shales as a response to increases in thermal maturation are still poorly constrained while efforts have been directed at unravelling the resource potential composition and textures of these economically important unconventional systems their spatial variability in chemistry and structure is still poorly documented at the sub micrometer scale here we have characterized samples of the lower toarcian posidonia shale samples from northern germany at varying stages of thermal maturation using a combination of compositional organic geochemistry and spectromicroscopy techniques including synchrotron based scanning transmission x ray microscopy stxm we document geochemical and mineralogical heterogeneities down to the nanometer scale within the investigated samples as a function of their level of thermal maturity in particular authigenic albite crystals containing nanometric halite inclusions have been documented within the investigated mature and overmature samples the presence of such tracers of palaeobrine carbonate interactions supports a maturation scenario for the lower toarcian posidonia shale intimately related to ascending brine fluids rather than a maturation scenario solely resulting from high heat flows in addition various types of asphaltene and nso rich bitumen have been detected within the same samples very likely genetically derived from thermally degraded organic precursors furthermore the formation of nanoporous pyrobitumen has been inferred for samples of gas window maturity likely resulting from the formation of gaseous hydrocarbons by providing in situ insights into the fate of bitumen and pyrobitumen as a response to the thermal evolution of the macromolecular structure of kerogen the results reported here constitute an important step towards better constraining hydrocarbon generation processes during natural shale gas maturation

porosity of devonian and mississippian new albany shale across a maturation gradient insights from organic petrology gas adsorption and mercury intrusion the evolution of porosity in shales with increasing maturity was examined in a suite of five new albany shale samples spanning a maturity range from immature vitrinite reflectance ro 0 35 to postmature ro 1 41 devonian to lower mississippian new albany shale samples from the illinois basin used in this study contain marine type ii kerogen having total organic carbon contents from 1 2 to 13 0 wt organic petrology co2 and n2 low pressure adsorption and mercury intrusion capillary pressure techniques were used to quantify pore volumes pore sizes and pore size distributions increasing maturity of the new albany shale is paralleled by many changes in the characteristics of porosity the total porosity of 9 1 vol in immature new albany shale decreases to 1 5 vol in the late mature sample whereas total pore volumes decrease from 0 0365 to 0 0059 cm3 g in the same sequence reversing the trend at even higher maturity the postmature new albany shale exhibits higher porosity and larger total pore volumes compared to the late mature sample with increasing maturity changes in total porosity and total pore volumes are accompanied by changes in pore size distributions and relative proportions of micropores mesopores and macropores porosity related variances are directly related to differences in the amount and character of the organic matter and mineralogical composition but maturity exerts the dominant control upon these characteristics we conclude that organic matter transformation due to hydrocarbon generation and migration is a pivotal cause of the observed porosity differences

a novel nmr surface relaxivity measurements on rock cuttings for conventional and unconventional reservoirs abstract surface relaxivity is an intrinsic rock property that makes low field nmr a valuable tool for determining pore size distribution of geological formations its value can vary considerably in different rocks depending on the type and distribution of the rock minerals rock surface wettability and petrophysical properties therefore laboratory measurement of is required on a case by case basis however existing nmr methods are expensive complex and most often require supplementary and expensive non nmr measurements rock samples are also required to be well consolidated and cylindrical so that experiments can be run at high pressures a barrier for measurements of unconsolidated and thinly laminated unconventional rocks this study proposes a new nmr method termed nmr grain sizing method that uses different grain sizes of a given rock to generate pores of corresponding sizes using a geometric constant grain specific surfaces are transformed to pore surfaces and the governing nmr equation is rearranged so that we have a method that measures from only nmr measurements on rock cuttings this approach is simple inexpensive and does not require supplementary measurements it offers an added advantage for characterizing thinly laminated formations a proof of concept is demonstrated for three unconventional rocks qusaiba shale jafurah carbonate mudrock and eagle ford and two conventional rocks berea sandstone and indiana limestone the ranges of surface relaxivity are 96 9 134 5 m s qusaiba shale 62 07 106 m s jafurah carbonate mudrock 55 9 68 72 m s eagle ford 35 51 43 2 m s berea sandstone and 33 2 40 54 m s indiana limestone all measurements are reproducible with 95 confidence interval the measured values for indiana limestone and berea sandstones were validated with micro ct based pore network models and also compare well with literature data measurement of qusaiba shale and jafurah carbonate source rocks are apparently reported for the first time here

unique and remarkable dilatometer measurements of pyroclastic flow generated tsunamis pyroclastic flows entering the sea may cause tsunamis at coastal volcanoes worldwide but geophysically monitored field occurrences are rare we document the process of tsunami generation during a prolonged gigantic collapse of the soufriere hills volcano lava dome on montserrat on 12 13 july 2003 tsunamis were initiated by large volume pyroclastic flows entering the ocean we reconstruct the collapse from seismic records and report unique and remarkable borehole dilatometer observations which recorded clearly the passage of wave packets at periods of 250 500 s over several hours strain signals are consistent in period and amplitude with water loading from passing tsunamis each wave packet can be correlated with individual pyroclastic flow packages recorded by seismic data proving that multiple tsunamis were initiated by pyroclastic flows any volcano within a few kilometers of water and capable of generating hot pyroclastic flows or cold debris flows with volumes greater than 5 10 6 m 3 may generate significant and possibly damaging tsunamis during future eruptions

controls of organic and inorganic compositions on pore structure of lacustrine shales of chang 7 member from triassic yanchang formation in the ordos basin china abstract to quantify the contributions of organic and inorganic compositions to pore volumes of chang 7 shales sub critical gas adsorption experiments were performed on a suite of shale and organic matter samples the parameters of pore structure were then calculated from the gas adsorption data the grain densities of the studied samples were also measured based on the total organic carbon toc contents and pore volumes of shale and organic matter samples the contributions of organic matter and inorganic compositions to pore volumes were estimated the results showed that the adsorbed gas volumes pore volumes surface areas and pore size distribution lines of organic matter samples were all higher than those of shale samples it indicated that organic matter was more porous than other fractions in the studied samples the average contributions of organic matter to the volumes of micropore mesopore and macropore are 45 98 27 20 and 33 27 respectively the contributions of organic matter to pore volume increased with the maturity which can be attributed to the formation of organic matter pores during maturation the contributions of organic matter to mesopore and macropore volumes correlated positively with toc content which suggested that toc content is another controlling factor of the contributions of organic matter to pore volume

eagle ford shale prospecting with 3d seismic data within a tectonic and depositional system framework the south texas eagle ford shale formation in is an important emerging shale play in the united states more than 1510 wells have either been drilled or permitted in the play what has emerged is a well defined downdip gas play that transitions rapidly updip into less well defined wet gas and oil fairways with initial gas well rates exceeding 17 million cubic feet per day and initial oil well rates in excess of 1000 barrels of oil per day common in the expanding play exploration companies are pursuing methods to optimize drilling plans limited well and core data describing the eagle ford require the use of 3d seismic to help characterize reservoir quality variations avoid drilling hazards and help predict sweet spots modern long offset full azimuth 3d is an essential tool for building a geophysical description of the shale between wells anisotropic time imaging feeding both acoustic and elastic inversions is helping operators gain better insight into the reser voir s variability the following discussion highlights components of an ongoing effort to extract value from seismic data in shale prospecting unfortunately limited well data for calibration as in many immature shale plays remains the primary constraint on confident linkage between the actual reservoir quality and seismic measurements

morphology genesis and distribution of nanometer scale pores in siliceous mudstones of the mississippian barnett shale research on mudrock attributes has increased dramatically since shale gas systems have become commercial hydrocarbon production targets one of the most significant research questions now being asked focuses on the nature of the pore system in these mudrocks our work on siliceous mudstones from the mississippian barnett shale of the fort worth basin texas shows that the pores in these rocks are dominantly nanometer in scale nanopores we used scanning electron microscopy to characterize barnett pores from a number of cores and have imaged pores as small as 5 nm key to our success in imaging these nanopores is the use of ar ion beam milling this methodology provides flat surfaces that lack topography related to differential hardness and are fundamental for high magnification imaging nanopores are observed in three main modes of occurrence most pores are found in grains of organic matter as intraparticle pores many of these grains contain hundreds of pores intraparticle organic nanopores most commonly have irregular bubblelike elliptical cross sections and range between 5 and 750 nm with the median nanopore size for all grains being approximately 100 nm internal porosities of up to 20 2 have been measured for whole grains of organic matter based on point count data from scanning electron microscopy analysis these nanopores in the organic matter are the predominant pore type in the barnett mudstones and they are related to thermal maturation nanopores are also found in bedding parallel wispy organic rich laminae as intraparticle pores in organic grains and as interparticle pores between organic matter but this mode is not common although less abundant nanopores are also locally present in fine grained matrix areas unassociated with organic matter and as nano to microintercrystalline pores in pyrite framboids intraparticle organic nanopores and pyrite framboid intercrystalline pores contribute to gas storage in barnett mudstones we postulate that permeability pathways within the barnett mudstones are along bedding parallel layers of organic matter or a mesh network of organic matter flakes because this material contains the most pores

sedimentology of rocky shorelines 3 hydrodynamics of megaclast emplacement and transport on a shore platform oahu hawaii abstract megaclasts of well cemented coralgal limestone have been emplaced onto a shore platform by large waves on the north shore of oahu hi emplacement and movements of the largest ca 96 ton megaclast have been dated using aerial photographs hydrodynamic forces at the low submerged shoreline cliff are computed using design wave characteristics based on linear wave theory and experimental results considering the local wave climate and near shore bottom topography force exerted by a tsunami has been estimated based on the 1946 aleutian tsunami the computed forces are evaluated in terms of the initial fracturing along a given failure plane that is required in order for the detachment to occur the analysis shows that tsunami as well as large swell waves are capable of quarrying the megaclast provided that sufficient initial fracturing is present dislodgement and emplacement most likely occurred in a sequence during impact of a single wave on the shoreline cliff swell waves however are seldom capable of emplacing large blocks onto the platform due to their rapid disintegration after breaking so that most blocks quarried from the cliff edge fall back onto the submarine terrace emplacement of large boulders seems to require extreme sea waves with periods longer than storms or north pacific swells usually produce transport mechanisms on the shore platform vary depending on megaclast shape sliding is a common mechanism of transport for larger and irregular megaclasts whereas somewhat smaller and platy megaclasts are occasionally found in overturned positions

possible pore structure deformation effects on the shale gas enrichment an example from the lower cambrian shales of the eastern upper yangtze platform south china abstract shale gas reservoir performance and canister desorption experiments of the lower cambrian organic rich shales in the eastern upper yangtze platform reveal a significant difference in shale gas content between the dabashan arc like fold thrust belt in northeastern chongqing deformed zone and the slightly folded area in southeastern chong non deformed zone integrated pore characterization methods including scanning electron microscopy sem low temperature n2 and co2 adsorption and mercury injection capillary pressure micp analyses were comparatively conducted in both areas in order to examine shale gas reservoir pore size variations and thus the possible microscopic pore structure controls on shale gas enrichment the lower cambrian shales in both deformed zone dz and non deformed zone ndz were deposited in the deep water shelf and show similar organic matter richness and thermal maturity the majority of organic matter om hosted pores in dz samples are in nanoscale size range with the dominance of micro fractures within the om or at the interface of om and minerals in contrast om hosted meso 2 50 nm to macropores 50 nm are the dominant pore types in the ndz samples om hosted micropores the dabashan arc like fold thrust belt took place by the end of the late triassic while the lower cambrian shales have reached thermal maturity peak om hosted meso 2 50 nm to macropores 50 nm in dz samples are most probably collapsed during structural deformation related to tectonic compression while micropores due to their smaller size survived the tectonic stress the om hosted micropores are the main storage space for adsorbed gas in the dz area the dominance of micro pores in dz and lack of connection between those pores and matrix pores led to higher gas content in dz samples on the contrary the well connected om hosted pore network in ndz allows easier gas flow in the rock matrix that eventually led to significant gas leakage during uplift and exhumation and lower gas content in this zone the results of this study suggest that structural deformation can potentially change the pore structure of shales and thus shale gas content which has major significance for shale gas exploration and development in south china where had experienced complex tectonic movements

cliff top megaclast deposits of ireland a record of extreme waves in the north atlantic storms or tsunamis past occurrences of major tsunami in the global record have often been inferred from the presence of megaclast accumulations at significant heights above sea level which sometimes exhibit a pronounced seaward directed imbricate fabric the aran islands off the west coast of ireland exist in a marine environment which is totally unprotected from the most extreme sea states encountered in the north atlantic spectacular megaclast accumulations are found along the tops of vertical cliffs on these islands the elevation of these deposits varies from 0 m to 50 m above mean sea level and they include clasts weighing 250 tonnes at sea level over 117 tonnes at 12 m and 2 9 tonnes at 50 m above sea level imbrication measurements on these megaclasts indicate a well defined and consistent mean direction from the southwest for the emplacing waves one that is consistent with the prevalent storm wind direction for the area the megaclast accumulations are subject to episodic and on going erosion by cliff retreat but the existing accumulations are estimated to record events since at least 1839 recent emplacement and reworking is evidenced by trapped plastic detritus within the deposits and eyewitness accounts of large storms during which clasts have been emplaced similar deposits are found on the exposed coasts of the shetland and orkney islands off scotland there is at present no evidence of any tsunami in recorded history affecting the western irish and scottish coasts other than those generated by the lisbon earthquake of 1755 where the wave effects were slight thus the presence of megaclast accumulations at significant heights above sea level on exposed coasts and exhibiting imbrication should not be used as a definitive criterion for the past occurrence of tsunami these deposits attest to extreme wave conditions occasionally encountered in the north atlantic and act as a record of such events extending back at least 160 years such data on extreme wave conditions are essential for the prediction of the effects of deepwater waves on structures such as offshore drilling platforms

analyzing successive landslide dam formation by different triggering mechanisms the case of the tangjiawan landslide sichuan china abstract the catastrophic tangjiawan landslide triggered by the 2008 wenchuan earthquake blocked the duba river impounding one of the most dangerous coseismic barrier lakes in beichuan china the lake was drained by an artificial spillway within one month after the earthquake to minimize the potential dam breach flooding risk however on september 5 2016 this landslide was reactivated and dammed the river again creating a 20 m high dam at the same location and resulting in the formation of a barrier lake with a volume of 0 6 million m3 the day after the event we carried out a field investigation of the landslide and obtained a high resolution image and dem using uav the satellite images from 2005 2008 2010 and 2015 were also collected to analyze the evolution of the landslide together with multi temporal dems the geometry and volumes of the displaced mass and the landslide dams and barrier lakes were calculated using image interpretation and 3d spatial analysis with gis this landslide is of great scientific interest as it presents a good example of multiple reactivation of a pre historical giant landslide under different triggering conditions a reactivation of an older landslide during the wenchuan earthquake and a second reactivation during a rainfall event several years later meanwhile from the hazard assessment and prevention perspective it is also representative as it dammed the river twice in 2008 and 2016 posing threats to both upstream and downstream areas we infer that the successive landslides in this region could be caused by the strong tectonic activities including earthquakes and high average uplifting rate the results of landslide volume analysis using multi temporal dems contribute to the landslide mechanism analysis and suggest that the landslide volume estimation is effected by the landslide type landslide rupture surface location and resolution of dem we also compare the performance of different empirical models of landslide stability and dam breach flood parameters and discuss their application during the quick assessment of the potential hazard of the landslide dams generally the successive landslide dams at the tangjiawan site are caused by the successive landslide reactivations on an anti dip slope controlled by strong tectonic activity and river erosion involve with a mass of loose materials of previous landslide deposition and possess high flood risk to the downstream area the experience gained in this work can be used to assist the hazard assessment and the planning of the emergency measures for similar landslide dams in the future

mapping an earthquake induced landslide based on uav imagery case study of the 2015 okeanos landslide lefkada greece abstract on november 17 2015 07 10 utc an earthquake of mw 6 5 induced slope failures mainly at the western part of the island of lefkada ionian sea greece the most characteristic one is the okeanos site deep seated landslide near village athani that affected the man made environment part of the site including a dirt road moved downwards along the coastal cliff and a luxury hotel suffered heavy damage the goal of this study is to map in detail the okeanos landslide and to provide relevant quantitative data i e structural data and volume of both the accumulated and removed material in order to achieve this a comparison between pre earthquake and post earthquake point clouds generated from aerial imagery and uav acquired photos took place using structure from motion the steep coastal cliff site was surveyed in detail even in areas that are difficult to approach results from this study show that the total landslide area covers a surface of 36 000 m2 while a removed volume of 93 000 m3 of landslide material was evaluated using change detection techniques in addition fieldwork and survey data revealed that the sliding surface was a pre existing fault surface upon which the geological material moved downwards the coastal cliff the sliding surface dips west and is exposed along a 115 m long and 25 30 m high section scarp as a conclusion this study underlines the importance of a thorough geological study in order to identify landslide prone areas prior to any building activity and shows that a uav survey is capable to provide adequate information during a post earthquake field survey for co seismic landslide mapping and modeling

erratum to the posidonia shale lower toarcian of sw germany an oxygen depleted ecosystem controlled by sea level and palaeoclimate palaeogeogr palaeoclimatol palaeocol 165 2001 27 52 abstract the lower toarcian posidonia shale is famous for its excellently preserved fossils and its high amount of organic matter up to 16 both quality of preservation and accumulation of organic matter have been explained by permanent anoxic bottom water conditions high resolution geochemical sedimentological and palaeoecological investigations of various sections of the posidonia shale in sw germany however indicate that oxygen availability was variable and ranged from short oxygenated periods to longer term anoxia the benthic macrofauna consists of nine fossil communities and was used in combination with geochemical data to reconstruct a time averaged oxygen curve anoxic conditions prevailed during the deposition of the toarcian black shales they were however punctuated by various short periods weeks to years with oxygenated bottom water conditions sedimentological e g distinctiveness of microlamination siliciclastic content and geochemical parameters e g organic matter content isotopic signatures 18 o and 13 c molecular redox parameters pristane phytane ratio arylisoprenoids exhibit a remarkable covariation and seem to be controlled by sea level fluctuation maximum oxygen depletion and an extreme negative shift of 13 c org values 34 occurred during the early falciferum zone this is explained by the recycling of 12 c enriched carbon derived from remineralization of organic matter on and within the substrate during low sea level stand and a highly elevated redox boundary including photic zone anoxia the subsequent transgression permitted enhanced water exchange with the tethyan ocean and caused improvement of living conditions at the end of the falciferum zone other important factors controlling the depositional environment are the overall palaeogeographic situation and climate the early jurassic is the latest period before break up of pangaea and probably was ruled by a strong meridional atmospheric circulation system with pronounced seasonal changes of prevailing trade and monsoon wind systems an estuarine circulation with a positive water balance and surface water with slightly reduced salinity in the summer alternated with an anti estuarine circulation and a negative water balance in the winter during the summer months a stratified water column with anoxic conditions below the halocline developed 18 o data indicate low salinity in the surface water during the monsoon influenced summer high productivity was then located in the photic zone and the corresponding isotopically light 18 o signal was fixed in the calcareous nannoplankton during the winter months a saline circulation system brought oxygen to the benthic environment favouring temporary benthic colonization especially during times of relative sea level high stand

wave emplaced coarse debris and megaclasts in ireland and scotland boulder transport in a high energy littoral environment a discussion scheffers et al 2009 describe a reconnaissance survey of boulder accumulations along parts of the atlantic coasts of the british isles a substantial part of their report concerns the characteristics of wave transported boulder deposits found high above sea level on cliffs these boulder deposits reach perhaps their ultimate development along the coasts of the aran islands galway bay western ireland and eshaness shetland northern scotland where evidence of wave action reaches elevations of 50 m above sea level a s l we have previously investigated in detail these and numerous other similar localities and concluded that the boulder deposits are cliff top storm deposits ctsds part of an assemblage of features found on certain cliffs on these very high energy coasts that relate to the impacts of extreme waves during major storms williams and hall 2004 hall et al 2006 2008 hansom et al 2008 hansom and hall 2009 however scheffers et al 2009 p 571 claim that at these and other sites no evidence exists for storm wave dislocation of boulders found at altitudes of 120 m a s l indeed no calculations of possible storm wave heights storm wave physics or ages of the deposits and no descriptions of extraordinary storms are sufficient to explain these displacements p 568 and alternative explanations such as tsunamis should be considered p 571 here we rebut these claims by briefly restat

megatsunami deposits on kohala volcano hawaii from flank collapse of mauna loa the origin of coastal and high elevation marine gravels on the hawaiian islands of lanai and molokai is controversial because the vertical tectonics of these islands is poorly constrained the gravels are either from eustatic highstands or were left by massive tsunamis from offshore giant landslides in contrast at kohala on the island of hawaii where continuous subsidence is well established lithofacies analysis and dating of a fossiliferous marine conglomerate 1 5 61 m above present sea level support a tsunami origin and indicate a runup of 400 m 6 km inland the conglomerate age 110 10 ka suggests a tsunami caused by the ca 120 ka giant alika 2 landslide from nearby mauna loa volcano

musings in tectonics i outline and discuss my career in the context of the history of structural geology and tectonics the progressive developments that led to plate tectonics the people who have encouraged and influ

evolution of porosity and pore types in organic rich calcareous lower toarcian posidonia shale low and high resolution petrographic studies have been combined with mineralogical toc rockeval and porosity data to investigate controls on the evolution of porosity in stratigraphically equivalent immature oil window and gas window samples from the lower toarcian posidonia shale formation a series of 26 samples from three boreholes wickensen harderode and haddessen in the hils syncline was investigated the main primary components of the shales are microfossiferous calcite 30 50 clay minerals 20 30 and type ii organic matter toc 7 15 hi 630 720 mg gc in immature samples characteristic sub centimetric light and dark lamination reflects rapid changes in the relative supply of these components total porosities decrease from 10 to 14 at ro 0 5 to 3 5 at ro 0 9 and then increase to 9 12 at ro 1 45 these maturity related porosity changes can be explained by a the primary composition of the shales b carbonate diagenesis c compaction and d the maturation micro migration local trapping and gasification of heterogeneous organic phases calcite undergoes dissolution and reprecipitation reactions throughout the maturation sequence pores quantifiable in sem ca 50 nm account for 14 25 of total porosity at ro 0 5 sem visible macropores1 are associated mainly with biogenic calcite at this maturity clays and organic matter are not visibly porous but nevertheless hold most of the shale porosity porosity loss into the oil window reflects a compaction b carbonate cementation and c perhaps the swelling of kerogen by retained oil in addition porosity is occluded by a range of bituminous phases especially in microfossil macropores and microfractures in the gas window mineral hosted porosity is still the primary form of macroporosity most commonly observed at the organic inorganic interface increasing porosity into the gas window also coincides with the formation of isolated spongy and complex meso and macropores within organic particles related to thermal cracking and gas generation this intraorganic porosity is highly heterogeneous point counted macroporosity of individual organic particles ranges from 0 to 40 with 65 of organic particles containing no macropores we suggest that this reflects the physicochemical heterogeneity of the organic phases plus the variable mechanical protection afforded by the mineral matrix to allow macroporosity to be retained the development of organic macroporosity cannot alone account for the porosity increase observed from oil to gas window major contributions also come from the increased volume of organic micro and meso porosity and perhaps by kerogen shrinkage

hydrocarbon generation and migration routes in the east texas basin the east texas basin is a prolific mature hydrocarbon province producing oil and gas from several reservoirs and a variety of trap types many of the liquid hydrocarbons discovered in the basin are trapped in structures related to movement of the underlying louann salt by determining the structural evolution of the basin we constructed a framework to model the generation of hydrocarbons in the basin geochemical data indicate three major oil types jurassic oil lower cretaceous oil and upper cretaceous oil the jurassic source is mature throughout the basin and began to expel oil at approximately 88 ma the distribution of jurassic oil in cretaceous reservoirs shows that vertical migration routes predominated prospective lower cretaceous source rocks are only matur in the deep central portion of the basin where expulsion began about 47 ma distribution of this oil type suggests that lower cretaceous source rocks occur only in localized areas of the east texas basin organic rich upper cretaceous shales are immature in the main part of the basin but are mature south of the angelina caldwell flexure where they reached peak generation at approximately 20 ma long distance lateral migration routes are necessary to explain the distribution of this oil type migration routes to the giant east texas field may be 100 km or more modeling of this basin suggests an exploration approach in mature basins of defining migration pathways and seeking traps astride them traps in this position have a better probability of being filled and all else being equal are likely to be better fields than traps located away from the major migration routes

huge erratic boulders in tonga deposited by a prehistoric tsunami along some coastlines there are erratic boulders apparently emplaced by tsunamis or cyclonic storms evaluating their origin and time of emplacement places constraints on the frequency severity and location of coastal hazards seven such large coral limestone boulders are present near fahefa village on tongatapu island southwest pacific apparently emplaced by a prehistoric tsunami these boulders are 10 20 m above sea level and above any possible source and all are 100 400 m from the present shoreline coral 230th ages indicate that the limestone formed during the last interglacial sea level highstand ca 120 130 ka the largest boulder is 20 times more massive than any reported boulders emplaced by historically documented storms and may be the largest known tsunami or storm erratic worldwide situated above its source we performed computer simulations to assess whether tsunamis produced by earthquakes undersea landslides or volcanoes could emplace the boulders the simulations indicate that either volcanic flank collapse along the tofua arc 30 40 km to the southwest or undersea landslides on the submarine slopes of tongatapu could be responsible either could explain why these boulders are not widespread on tongatapu and instead occur in a localized group along the western coast this study demonstrates that small 1 km3 submarine slope failures sometimes generate locally large tsunamis the fahefa boulders are in a well studied and well populated area yet were unknown to the scientific community until recently this suggests that systematic searches elsewhere for erratic boulders and other tsunami deposits might provide new information for assessing the size and extent of prehistoric tsunamis

self sedimentation of phytoplankton blooms in the geologic record abstract understanding the formation of laminated organic rich sediments is an essential topic for researchers interested in fossil fuels biogeochemical cycles earth s environmental history and global change biologists have very recently demonstrated that some marine phytoplankton blooms actively govern their own sedimentation by the formation of sticky transparent gels that facilitate rapid aggregation accelerated sinking and efficient export flux here we present fossil evidence of unfragmented low diversity phytoplankton assemblages preserved as sedimentary laminae and irregular flocs that are attributable to a similar phytoplankton driven sedimentary mechanism we term self sedimentation the geological evidence suggests that self sedimentation precludes significant heterotrophic grazing propels the formation of some conspicuous hemipelagic sedimentary laminae and results in efficient carbon and opal flux to the sediments we suggest that the self sedimentation phenomenon may have broad implications for the geological history of biogeochemical cycling oceanic ecological dynamics and abrupt atmospheric environmental change broader recognition of the self sedimentation phenomenon as explicitly defined here is a prerequisite to testing these unconventional hypotheses

microstructural investigation of gas shales in two and three dimensions using nanometer scale resolution imaging the microstructure of gas shale samples from nine different formations has been investigated using a combination of focused ion beam fib milling and scanning electron microscopy sem backscattered electron bse images of fib cross sectioned shale surfaces show a complex microstructure with variations observed among the formations energy dispersive spectroscopy of the shale cross sections indicates that clay carbonate quartz pyrite and kerogen are the most prevalent components in the bse images areas of kerogen are observed interspersed with the inorganic grains pores are observed in both the kerogen and inorganic matrix with the size shape and number of pores varying among the shale samples by using fib milling and sem imaging sequentially and repetitively three dimensional 3 d data sets of sem images have been generated for each of the shale samples three dimensional volumes of the shales are reconstructed from these images by setting thresholds on the gray scale the kerogen and pore networks are segmented out and visualized in the reconstructed shale volumes estimates of kerogen and pore volume percentages of the reconstructed shale volumes have been made and range from 0 to 90 0 for the kerogen and 0 2 to 2 3 for pores estimates of pore size distributions suggest that although pores with radii of approximately 3 nm dominate in number they do not necessarily dominate in total volumetric contribution scanning electron microscopy images and 3 d reconstructions reinforce the facts that shales are quite different and that their microstructures are highly variable and complex