relation between depositional environment and the elemental composition of early diagenetic siderite early diagenetic siderites from marine and fresh water depositional environments are characterized by distinctive compositional trends siderite from fresh water environments is often relatively pure i e greater than 90 mol feco sub 3 and commonly attains end member composition siderite from marine environments however is always extremely impure and has extensive substitution of mg up to 41 mol and to a lesser extent ca up to 15 mol for fe in the siderite lattice in addition marine siderite generally contains less mn and has a higher mg ca ratio than fresh water siderite this compositional variation appears to result from differences in the chemistry of early marine and meteoric pore waters inasmuch as early marine pore waters generally have a higher mg sup 2 ca sup 2 ratio and contain less mn sup 2 and fe sup 2 and more ca sup 2 and mg sup 2 than meteoric waters

earthquake data analysis an example from sweden abstract methods and results of earthquake data analysis are illustrated by the seismicity of sweden in the period 1951 1976 summarizing a comprehensive research project for the past five years starting from the regional structural properties methods are given for the evaluation of instrumental and macroseismic observations including error analysis and source identification the resulting earthquake distribution is investigated in relation to space various types of seismicity mapping time periodicities and magnitude frequency magnitude and energy magnitude relations the tectonophysical explanations of the earthquake origin are still subject to considerable uncertainty and can be treated only by way of discussions the engineering applications stimulated recently by the nuclear power industry can be placed on much more reliable ground they include calculations of seismic risk and fracture risk as well as investigations of certain phenomena of practical consequences especially rockbursts this review is primarily addressed to those who have use for seismological data in their work especially geologists tectonophysicists and engineers it is important for them to realize how the seismological data are obtained their reliability and their range of application sweden is here mainly used as an example but the developed methods have a general applicability to any earthquake region with proper modifications in short our purpose is two fold 1 to summarize recent research on the seismicity of sweden 2 to introduce all users of seismological data into methods and results

automatic approach for increasing the location accuracy of slow moving landslide endogenous seismicity the apoloc method seismological observations offer valuable insights on the stress strain states the physical mechanisms and the possible precursory signs of activation of various earth surface processes i e volcanoes glaciers and landslides comprehensive catalogues of the endogenous landslide seismicity that is corresponding to seismic sources generated by the unstable slope from either mechanical or hydrological origins should include the typology and an estimate of the source parameters location magnitude of the event these advanced catalogues constitute a strong basis to better describe the slope deformation and its time evolution and better understand the controlling factors because the number of seismic events in landslide catalogues is generally large automatic approaches must be considered for defining both the typology and the location of the sources we propose here a new location approach called automatic picking optimization and location method apoloc for locating landslide endogenous seismic sources from seismological arrays located at close distance the approach is based on the automatic picking of the p waves arrivals by optimizing the intertrace correlations the method is tested on calibration shots realized at the super sauze landslide southeast french alps and compared to other location approaches by using a realistic velocity model obtained from a seismic tomography campaign apoloc reduces the epicentre errors to 23 m on average compared to ca 40 m for the other approaches apoloc is then applied for documenting the endogenous seismicity i e slopequakes and rockfalls at the landslide

microseismic emissions from flowslide type movements in south wales abstract many of the unstable hillslopes of south wales have landslides that turn into flowslides over part of their tract the valley slopes at pant teg and glynrhigos are unstable as they possess the optimum requirements for slope failure they have probably been affected by repeated movements during the last 10 000 years significant acoustic emissions ae have been recorded from two landslide sites both subsequent to a major failure pant teg and during continuous movement glynrhigos four distinct types of ae have been recognised so far with frequencies in the 1 7 khz bandwidth with particular peaks at 1 2 2 0 4 2 4 9 5 5 and 6 5 khz the results indicate that there is a potential in developing a warning system for identifying increasing instability

siderite concretions from nonmarine shales westphalian a of the pennines england controls on their growth and composition back scattered electron microscopy has been used to examine the microstructure of nonmarine shale hosted siderite concretions the concretions are composed of 50 100 micrometer zoned crystallites which exhibit no noticeable center to edge variation within any individual concretion this indicates that siderite crystallites nucleated at virtually the same time across the entire concretion and that the concretions did not grow by radial addition of siderite layers around a central nucleus further siderite precipitation took place by crystal growth onto the nuclei the total proportion of siderite in any part of the concretion bears no simple relationship to the porosity of the enclosing shale at the time of precipitation and growth by passive precipitation in pore space is unlikely integration of microprobe data with bulk mineral chemical and stable isotope data suggests that the siderite crystallites are composed of an fe mn rich end member with a delta 13 c value of approximately 10 per mil and a mg ca rich end member with a delta 13 c value of approximately 0 per mil to 5 per mil the mineral chemical and stable isotope compositions of these concretions resulted from microbially mediated processes operating close 10 m to the sediment water interface during methanogenesis methanogenesis can generate low delta 13 c as well as high delta 13 c carbonate cements hence deep burial diagenetic reactions such as decarboxylation of organic matter need not be invoked to generate solutes for siderite precipitation

spatiotemporal sequence of himalayan debris flow from analysis of high frequency seismic noise 1 during the 2003 summer monsoon the hi climb seismological stations deployed across the himalayan range detected bursts of high frequency seismic noise that lasted several hours to days on the basis of the cross correlation of seismic envelopes recorded at 11 stations we show that the largest transient event on 15 august was located nearby a village partially destroyed on that day by a devastating debris flow this consistency in both space and time suggests that high frequency seismic noise analysis can be used to monitor debris flow generation as well as the evacuation of the sediment a systematic study of one year of seismic noise focusing on the detection of similar events provides information on the spatial and temporal occurrence of mass movements at the front of the himalayas with a 50 probability of occurrence of a daily event a total of 46 debris flows are seismically detected most of them were generated in regions of steep slopes large gullies and loose soils during the 2003 summer monsoon storms these events are compared to local meteorological data to determine rainfall thresholds for slope failures including the cumulative rainfall needed to bring the soil moisture content to failure capacity the inferred thresholds are consistent with previous estimates deduced from soil studies as well as sediment supply investigations in the area these results point out the potential of using seismic noise as a dedicated tool for monitoring the spatiotemporal occurrence of landslides and debris flows on a regional scale

accelerated pacific plate movements and climatic changes on time scales of 102 103 years in the late quaternary a synthesis abstract sea level curves constructed for the japan region for the period 14 000 to 10 000 years b p reveal inconsistencies in sea level during the intervals 10 000 10 500 11 500 12 000 and 13 000 13 500 years b p these intervals correspond to episodes of global climatic deterioration and catastrophic volcanic activity in japan these inconsistencies are explained on the basis of field observation by geoidal change and reactivation of the pacific plate movements from a glacio eustatic sea level curve it is supposed that the reactivation of the pacific plate movements was induced by mass redistribution within the earth due to rapid melting of polar ice furthermore the rapid spreading within the ocean basins greatly increased upwelling and this change in the ocean circulation resulted in abrupt global climatic cooling similar phenomena are recognized after 8000 and 130 000 years b p

characterization of alpine rockslides using statistical analysis of seismic signals 1 seismic data analysis is a powerful tool for remote characterization of rock slope failures here we develop quantitative estimates of fundamental rockslide properties e g volume based solely on data from an existing regional seismic network we assembled a data set of twenty known rockslides in the central alps with volumes between 1 000 and 2 000 000 m3 and analyzed their corresponding seismograms common signal characteristics include emergent onsets slowly decaying tails and a triangular spectrogram shape the main component of seismic energy is contained in frequencies below 3 4 hz while higher frequency signals may be caused by block impacts location estimates were generated using automatic arrival time picks and resulted in a mean location error of 10 9 km a linear relationship for the detection limit of a rockslide as a function of volume was identified for our seismic station network to estimate rockslide volume runout distance drop height potential energy and fahrboschung angle of reach we extracted five simple metrics from each seismogram signal duration peak value of the ground velocity envelope velocity envelope area risetime and average ground velocity using multivariate linear regression the combination of duration peak envelope velocity and envelope area best estimated event parameters with r2 values ranging between 0 8 and 0 88 three new rockslides were then used to validate our method and volume runout drop height and potential energy were estimated within the correct order of magnitude when provided with a suitable data set of rockslide events our method can be easily adapted to other regions and seismic networks

formation of siderite mg calcite iron sulphide concretions in intertidal marsh and sandflat sediments north norfolk england concretions cemented mainly by siderite mg calcite and iron monosulphide are common in late holocene marsh and sandflat sediments on parts of the north norfolk coast field experiments have shown that the concretions are actively forming in reduced sediments in which sulphate reducing bacteria are active 13c values ranging from 3 to 11 8 mean 5 9 0 suggest that the carbonate in the concretions is derived partly from marine sources and partly from microbial degradation of organic matter 18o values ranged from 6 4 to 0 8 mean 1 0 suggesting that carbonate precipitated in porewaters ranging from pure sea water to sea water diluted with meteoric water chemical analysis of porewaters showed no evidence of significant sulphate depletion at the depth of concretion formation some concretions have formed around fragments of wood or metal but others contain no apparent nucleus in field experiments siderite fes and mg calcite were precipitated around several different nuclei within a period of six months we suggest that siderite may form wherever the rate of iron reduction exceeds the rate of sulphate reduction such that insufficient dissolved sulphide is available to precipitate all the available dissolved ferrous iron

seismic monitoring system for landslide hazard assessment and risk management at the drainage plant of the peschiera springs central italy abstract the assessment of landslide hazards and design of strategies for managing the related risk have been widely studied topics in the scientific community due to the settlements infrastructures and tourist and cultural heritage sites that may be threatened by deformations involving unstable slopes engineering geological and geophysical techniques have been recently integrated in multidisciplinary approaches to study gravity induced slope instabilities and monitor their evolution the slope that hosts the peschiera springs drainage plant central italy is involved in a mass rock creep process associated with deep karst dissolution due to the importance of this infrastructure which provides water to the rome aqueduct an accelerometric network was installed in 2008 and a nanoseismic array was added in 2014 in this paper data recorded by the nanoseismic array were used to locate 397 microseismic events related to the slope instability process distinguished into two types with different waveforms 16 failures and 381 collapses the failures were distributed throughout the slope while the collapses exhibited two spatially separate clusters below the groundwater level at a depth where karst processes produce cavities the clusters were analysed as two distinct microseismic sources characterised by specific frequency magnitude curves of events that describe their attitude to produce events of different magnitudes regarding the accelerometric network an automated procedure was developed for quickly analysing the seismic records which include signals from teleseisms and near to far field earthquakes that can induce deformation in the landslide involved slope the results obtained by the two seismic monitoring systems were integrated with the aim of implementing a landslide hazard matrix based on the statistical frequency of the occurrence of such events and their probability of exceedance during a reference period providing a useful tool for managing the related landslide risk

seismic monitoring of rockfalls slide quakes and fissure development at the super sauze mudslide french alps applying the method nanoseismic monitoring to the fast moving mudslide in super sauze french alps we observed different types of seismic events caused by varying slope dynamics we identified signals caused by rockfalls in the source area of the slope and different types of signals which had obviously been generated by material failure within the unstable part of the mudslide signal analysis and further investigations e g the analysis of magnitude frequency distribution and simultaneous measurements by nanoseismic monitoring and extensometer devices revealed the generation of the observed seismic signals fracture processes i e slide quakes within the unstable sediments and the development of fissures at the slope s surface the spatial distribution of the epicenters slide quakes respectively the estimated source area fissure development correlates well with parts of the slope moving with higher velocities at the surface most of these signals were generated close to the in situ crests which are mostly covered by the mudslide material today indicating specific dynamics in these particular slope areas

crustal movements and geodynamics in fennoscandia abstract morner n a 1981 crustal movements and geodynamics in fennoscandia in p vyskocil r green and h malzer editors recent crustal movements 1979 tectonophysics 71 241 251 the fennoscandian shield the classical area of glacial isostasy has been subjected to a complex sequence of motions throughout the late cenozoic still the geometry of the areas deformed has been roughly the same an asthenosphere of low viscosity 1020 1021 poises and a lithosphere of high flexural rigidity are established the present uplift represents an other mechanism than the rapid glacial isostatic readjustment of the low viscosity asthenosphere and seems to originate from mesospheric motions at around 1900 1910 there was a distinct geodynamic change which seems to be controlled by changes in the earth s rate of rotation the postglacial uplift of fennoscandia is found to be associated with intensive neotectonism faulting fracturing and seismicity

analysis of rock fall and rock fall avalanche seismograms in the french alps this study reviews seismograms from 10 rock fall events recorded between 1992 and 2001 by the permanent seismological network sismalp in the french alps a new seismic magnitude scale was defined which allowed us to compare and classify g round motion vibrations generated by these alpine rock falls each rock fall has also been cha racterized by its ground motion duration t30 at an epicentral distance of 30 km no relation was found between rock fall parameters fall height runout distance volume potential energy and rock fall s eismic magnitudes derived from seismogram amplitudes on the other hand the signal duration t30 shows a rough correlation with the potential energy and the runout distance highlighting the co ntrol of the propagation phase on the signal length the signal analysis suggests the existence of at le ast two distinct seismic sources one corresponding to the initial rupture associated with an elastic r ebound during the detachment and the other one generated by the rock impact on the slope although the fall phenomenon includes other complex processes fragmentation of the block interaction with topography plastic deformation during and after impact 2d finite element simulations of thes e two seismic sources are able to retrieve the main seismogram characteristics

seismic precursory patterns before a cliff collapse and critical point phenomena 1 we analyse the statistical pattern of seismicity before a 1 2 103 m3 chalk cliff collapse on the normandie ocean shore western france we show that a power law acceleration of seismicity rate and energy in both 40 hz 1 5 khz and 2 hz 10khz frequency range is defined on 3 orders of magnitude within 2 hours from the collapse time simultaneously the average size of the seismic events increases toward the time to failure these in situ results are derived from the only station located within one rupture length distance from the rock fall rupture plane they mimic the critical point like behavior recovered from physical and numerical experiments before brittle failures and tertiary creep failures our analysis of this first seismic monitoring data of a cliff collapse suggests that the thermodynamic phase transition models for failure may apply for cliff collapse

automatic discrimination among landslide explosion quake and microtremor seismic signals at stromboli volcano using neural networks in this article we report on the implementation of an automatic system for discriminating landslide seismic signals on stromboli island southern italy this is a critical point for monitoring the evolution of this volcanic island where at the end of 2002 a violent tsunami occurred triggered by a big landslide we have devised a supervised neural system to discriminate among landslide explosion quake and volcanic microtremor signals we first preprocess the data to obtain a compact representation of the seismic records both spectral features and amplitude versus time information have been extracted from the data to characterize the different types of events as a second step we have set up a supervised classification system trained using a subset of data the training set and tested on another data set the test set not used during the training stage the automatic system that we have realized is able to correctly classify 99 of the events in the test set for both explosion quake landslide and explosion quake microtremor couples of classes 96 for landslide microtremor discrimination and 97 for three class discrimination landslides explosion quakes microtremor finally to determine the intrinsic structure of the data and to test the efficiency of our parametrization strategy we have analyzed the preprocessed data using an unsupervised neural method we apply this method to the entire dataset composed of landslide microtremor and explosion quake signals the unsupervised method is able to distinguish three clusters corresponding to the three classes of signals classified by the analysts demonstrating that the parametrization technique characterizes the different classes of data appropriately

automatic detection and discrimination of volcanic tremors and tectonic earthquakes an application to ambrym volcano vanuatu abstract an algorithm of automatic detection and discrimination of volcanic tremors defined as events containing only p type wave and tectonic earthquakes containing both p and s waves is applied on data recorded on a 3 component sts 2 broad band seismometer installed from july to november 2000 at ambrym volcano vanuatu the algorithm consists in detecting p waves and if any s waves according to a modified version zhizhin m rouland d bonnin j gvishiani a burtsev a 2006 rapid estimation of earthquake source parameters from pattern analysis of waveforms recorded at a single 3 component station bull seism soc am 96 6 2329 2347 of the component energy comparison method cecm proposed by nagano et al nagano k niitsuma h chubachi n 1989 automatic algorithm for triaxial hodogram source location in downhole acoustic emission measurement geophysics 54 4 508 513 the duration and maximum amplitude are automatically measured for each volcanic tremor and for each tectonic earthquake with corresponding duration and amplitude magnitudes during the four and half months of observation 1959 local and regional tectonic earthquakes with epicentral distances estimated from s p interval time ranging from a few kilometres to about 800 km and 14942 volcanic tremors with duration ranging from 10 to 2000 s have been detected the gutenberg and richter laws of tectonic earthquakes and volcanic tremors are examined according to their duration and amplitude magnitudes and completeness of the corresponding catalogues is studied the observations on the coherence of some long duration volcanic tremors which display four different intermittencies 77 17 min 165 10 min 565 50 min 1065 50 min are interpreted as different types of degassing

origin and timing of siderite cementation in upper ordovician glaciogenic sandstones from the murzuq basin sw libya the origin and timing of siderite cementation have been constrained in relation to depositional facies and sequence stratigraphy of upper ordovician glaciogenic sandstones from the murzuq basin sw libya optical microscope backscattered electron imagery and carbon and oxygen stable isotope analysis have revealed that siderite is of eo and mesogenetic origin eogenetic siderite is mg poor with a mean composition of fe91 7mg1 5ca0 3mn6 5 co3 and occurs in paraglacial tide dominated deltaic highstand systems tract hst sandstones in paraglacial foreshore to shoreface hst sandstones and in postglacial gilbert type deltaic lowstand systems tract lst sandstones this siderite is typically of meteoric water origin that influxed into the lst and hst sandstones during relative sea level fall and basinward shift of the strandline mesogenetic siderite which engulfs and thus postdates quartz overgrowths and illite is mg rich with a mean composition of fe72 2mg21 7ca0 8mn5 3 co3 and occurs in the paraglacial tide dominated deltaic hst sandstones in paraglacial foreshore to shoreface hst sandstones in glacial tide dominated estuarine transgressive systems tract tst sandstones in postglacial gilbert type deltaic lst sandstones and in postglacial shoreface tst sandstones 18ov pdb values of this siderite which range between 22 6 and 13 8 suggest that precipitation has occurred from evolved formation waters with 18o values between 14 0 and 1 0 and was either meteoric mixed marine meteoric and or marine in origin by assuming postdating quartz overgrowths and illite temperature between 80 and 130 c

microseismic activity within a serac zone in an alpine glacier glacier d argentiere mont blanc france a passive seismic study was carried out underneath glacier d argenti ere mont blanc france where an array of seismometers was installed in a subglacial access tunnel the data show a very high emissivity from the glacier fracturing can be discriminated from serac falls using the signal characteristics we apply seismic array methods to locate the sources of these signals using a two step grid search in the parameter space four clusters of activity are found close to the network showing that this fracturing does not take place uniformly over the glacier but rather in isolated small zones we compute a local magnitude using regional earthquakes for calibration the magnitudes follow a classical gutenberg richter law in the range ml 3 to 0 15 showing that no characteristic size events dominate the process we suggest that those spatial clusters of icequakes could reveal the heterogeneous nature of the friction at the base of the glacier with patches of high frictional stresses locally generating intense fracturing within the ice mass

pre collapse identification of sinkholes in unconsolidated media at dead sea area by nanoseismic monitoring graphical jackknife location of weak sources by few low snr records summary the sudden failure of near surface cavities and the resulting sinkholes have constituted a recent hazard affecting the populations lifelines and the economy of the dead sea region this paper describes how seismic monitoring techniques could detect the extremely low energy signals produced by cavitation in unconsolidated layered media dozens of such events were recorded within a radius of 200 m during several night time experiments carried out along the western dead sea shores the absence of prior knowledge about cavitation induced events in unconsolidated media required an initial signal characterization for which a series of source processes were simulated in the field under controlled conditions the waveform analysis by sonograms recognizes two main groups of seismic events impacts on dry material and impacts in liquid our analysis demonstrates that the discrimination between both types of source functions is robust despite the extreme nature of the scatter media in addition to their association with specific source processes these events can be precisely located by a graphical error resistant jackknifing approach using an extended m l scale their source energy can be quantified and related to standard seismic activity in summary it is now possible to monitor subsurface material failures before sinkhole collapse since the discrimination of impact signals on the basis of their frequency content is indicative of the maturity of the cavitation process

monitoring of snow avalanches using a seismic array location speed estimation and relationships to meteorological variables 1 monitoring snow avalanches is necessary in order to better understand their triggering mechanisms and ultimately improve forecast performance seismic monitoring has been developed by several groups over the last 20 years and holds great potential to detect locate and characterize snow avalanches during the 2009 2010 winter a seismic antenna was installed in the french alps close to the village of saint christophe en oisans 1700 m above sea level the array of seven sensors operated during 50 days in october and november 2009 under snow free conditions and during 40 days in january and february 2010 in presence of snow it recorded different types of seismic events including snow avalanches rockfalls shots and regional and local microearthquakes eighty avalanche signals were visually identified using a beam forming method we were able to locate snow avalanches on slopes of various orientations in a radius of about 3 km and track their propagation the location technique allowed for the estimation of avalanches front speed which ranged between 12 and 32 m s 1 the method can also distinguish dry and wet snow avalanches durations of avalanches can be as long as 380 s because of the length of the slopes in the area seismic monitoring provides a catalog of avalanches with precise times which can be used to analyze the impact of meteorological forcings on the avalanche triggering snowfall is found to be the dominant forcing of avalanche activity during this period as revealed by the strongest correlation for the period of study our results suggest that the impact of precipitation on the snowpack instability lasts for about 6 days

petrology and palaeoenvironmental significance of authigenic iron rich clays carbonates and apatite in the claiborne group middle eocene ne texas the claiborne group eocene in north east texas consists of clayey sandstones and mudrocks both with variable proportions of dark green to brown clay pellets deposited in a marginal to open marine setting on the gulf coast margin the composition of concretionary carbonate and clay pellets from 5 localities has been investigated using a wide variety of analytical techniques our palaeontological sedimentological c s and stable isotope data support an interpretation of marginal marine facies with limited freshwater input for the claiborne group dark green mature pellets are predominantly associated with transgressive bioturbated marine sediments from the weches formation through to the youngest crockett formation there is a trend from pellets composed mostly of dark green serpentine rich mixed layer clay to those of mostly brown immature nontronite rich mixed layer clay the serpentine is intermediate between odinite and berthierine and may have been originally odinite that has undergone partial transformation to berthierine pellet maturity apparently corresponds with the degree of winnowing and sedimentation rate it does not appear to correspond with global temperature fluctuations though the serpentine rich rather than glauconite rich composition may do siderite cement mostly in the form of concretions post dates the iron rich clay pellets and pre dates calcite cement carbonate and apatite concretions show a wide range of mineral cement textures reflecting variation in sedimentary environment and early diagenetic processes based on water temperatures derived from verneriacardia bivalves a precipitation temperature of 20 c is assumed for the concretionary siderite using this temperature we surmise that the siderite precipitated from marine pore waters with intermittent meteoric water mixing

differential glacio isostatic uplift of crustal blocks at glen roy scotland abstract detailed measurements of the altitudes of the shorelines of former ice dammed lakes in glen roy and vicinity in the scottish highlands prove erroneous the conventional view that former shorelines in areas affected by glacio isostatic uplift are uniformly tilted and or gently warped the measurements demonstrate differential uplift of blocks of the earth s crust the surfaces of some blocks have no detectable tilt whereas others have gradients up to at least 4 6 m km and are tilted in different directions in three areas 0 7 2 0 km long shorelines are distorted by crustal movements all these areas have landslides attributed to earthquakes that accompanied the release of stress in the area of greatest local distortion three shorelines rose about 3 m above their average altitudes for the immediately surrounding area and a fault scarp was produced possibly these local distortions accompanied catastrophic lake drainage by jokulhlaup analogous to crustal movements associated with man made lakes a relationship between crustal movement and the limit of a glacial advance is demonstrated these findings have implications for other parts of the world affected by glacioisostatic uplift

early diagenesis and its relationship to depositional environment and relative sea level fluctuations upper cretaceous marshybank formation alberta and british columbia early diagenesis of the upper cretaceous late coniacian to early santonian marshybank formation was controlled by depositional environment composition of depositional water fe and organic content of the sediment sedimentation rate proximity to the shoreline and influx of meteoric water related to relative sea level fall five depositional environments each characterized by a distinct early diagenetic mineral assemblage have been recognized offshore shelf sediments that were deposited in a dysaerobic environment are characterized by abundant framboidal pyrite and rare septarian concretions composed of early calcite and siderite intense sulphate reduction promoted by the dysaerobic depositional water was the primary influence on early diagenesis offshore shelf sediments deposited under aerobic conditions are characterized by abundant concretions composed of two generations of siderite s1 and s2 in this environment methanogenesis rather than sulphate reduction was more important early diagenesis of the inner shelf sands was generally limited however in sands deposited proximal to the shoreline mixing of marine and meteoric waters promoted crystallization of fe rich chlorite and siderite the shoreface was characterized by dissolution of detrital minerals in the upper portion and precipitation of kaolinite or illite smectite in the lower portion in the coastal plain environment brackish water and early reducing conditions resulted in formation of abundant euhedral pyrite ankerite rather than siderite is the typical early diagenetic carbonate the 18o values of the earliest cements i e early calcite siderite s1 inner shelf siderite indicate crystallization from a low 18o marine derived porewater assuming crystallization at 25 c a 18o value of about 7 smow can be estimated for the seaway during marshybank formation time similar calculations for the overlying dowling member puskwaskau formation suggest that the 18o value of the seaway increased to about 4 smow consistent with its transgressive nature very low 18o values are exhibited by siderite s2 these results indicate crystallization during intermediate diagenesis 60 c from meteoric water 15 smow that entered the marshybank formation during sea level lowstand

microseismic investigation of an unstable mountain slope in the swiss alps 1 risks associated with unstable rocky slopes are growing as a result of climate change and rapid expansions of human habitats and critical infrastructure in mountainous regions to improve our understanding of mountain slope instability we developed a microseismic monitoring system that operates autonomously in remote areas afflicted by harsh weather our microseismic system comprising 12 three component geophones was deployed across 60 000 m 2 of rugged crystalline terrain above a huge 30 million m 3 recent rockfall in the swiss alps during its 31 month lifetime signals from 223 microearthquakes with approximate moment magnitudes ranging from 2 to 0 were recorded determining the hypocenters was challenging for several reasons 1 p wave velocities were highly heterogeneous varying abruptly from 3 8 km s 2 first break picks were either inaccurate or lacking for some microearthquakes 3 there were no reliable s wave picks 4 numerous microearthquakes occurred just outside the network boundaries these issues were addressed by using a three dimensional 3 d p wave velocity model of the mountain slope determined from refraction tomography in a nonlinear inversion for hypocenter parameters and their probability density functions recordings from geophones at different altitudes and in boreholes constrained microearthquake depth estimates most microearthquakes were concentrated within 50 100 m of the surface in two zones one that followed the recent rockslide scarp and one that spanned the volume of highest fracture zone fault density these two active zones delineated a mass of rock that according to geodetic measurements has moved toward the scarp at 1 2 cm yr

a new geochemical classification of sedimentary environments because of the relative constancy of ph in most subaqueous sediments and the general lack of measurability of eh these parameters are not practically useful for classifying sedimentary environments in their place a new classification is offered which derived from studies of modern sediments is based on the presence or absence of dissolved oxygen and dissolved sulfide in the sediments at the time of authigenic mineral formation sedimentary environments are first of all divided into oxic and anoxic depending upon the presence or absence of measurable dissolved oxygen anoxic environments in turn are divided into sulfidic and non sulfidic depending upon the presence of measurable dissolved sulfide anoxic nonsulfidic environments are further divided into postoxic or resulting from oxygen removal without sulfate reduction weakly reducing and methanic or resulting from complete sulfate reduction with consequent methane formation strongly reducing the environments are shown to succeed one another during early diagenesis in the order oxic post oxic sulfidic methanic iron and manganese minerals characteristic and stable in each environment are listed and discussed so that they may be used to distinguish the environments when studying the ancient geological record

quaternary sea level changes in western scotland abstract in recent years major advances have been made in our understanding of late quaternary sea level changes in western scotland in particular new hypotheses have been advanced to explain the ages and origins of high level rock platform fragments and high level marine shell beds certain raised shorelines in islay and jura sw argyll and wester ross have been related to former margins of the last ice sheet and are associated with drops in the lateglacial marine limit in some areas the decline in lateglacial sea level took place in association with a stationary ice margin while in others the fall in sea level occurred in conjunction with considerable ice retreat during the lateglacial interstadial relative sea level fell rapidly between ca 13 and ca 12 ka bp and thereafter more slowly until ca 11 ka bp renewed marine erosion during the cold climate of the loch lomond younger dryas stadial ca 11 10 ka bp resulted in the production of the main lateglacial shoreline which declines in altitude to the w sw and s away from the centre of glacio isostatic uplift in the w highlands the shoreline has a maximum altitude of 10 11 m o d in the oban area and passes below sea level in ne islay ardnamurchan colonsay w mull kintyre and arran during the early holocene a pronounced marine transgression took place probably culminating between 6 6 and 7 0 ka bp the culmination of the transgression is represented by the main postglacial shoreline that reaches a maximum altitude of ca 14 m in the oban area and declines gently in altitude away from the centre of glacio isostatic uplift reconstruction of the uplift isobases for this shoreline appears to indicate a slight eastward migration of the uplift centre since the younger dryas in peripheral areas of western scotland the main postglacial shoreline is not present owing to the effect of holocene submergence

geochemistry of early carbonate cements in the cardium formation central alberta abstract authigenic minerals and diagenetic textures in the marine conglomerates and sandstones of the cretaceous cardium formation in the northeast pembina area preserve a complex sequence of diagenetic events textural relationships observed in thin section and under the scanning electron microscope were used to determine the relative timing of diagenetic events in these marine sediments paragenetic sequences are similar for the conglomerate sandstone and siderite nodules in the enclosing shales extensive cementation by siderite and calcite occurred early in the diagenetic history before any significant compaction the geometry and distribution of lithofacies in the cardium may have influenced the diagenesis and internal stratigraphy of the conglomerate overlying shale matrix conglomerate may have trapped upward migrating fluids increased in buoyancy by dissolved co2 produced by decay of organic matter in the enclosing shales these fluids could have infiltrated the upper portion of open matrix conglomerate causing cementation petrographic evidence shows alternating precipitation of siderite and pyrite implying fluctuating activities of dissolved carbonate and hydrogen sulfide probably caused by bacterially mediated processes during early diagenesis early sequences of siderite and pyrite precipitation can be related to zones of iron reduction sulfate reduction and possibly decarboxylation during diagenesis carbon and oxygen isotopic data indicate a systematic change in the isotopic compositions of calcite and siderite from 25 to 3013c and 018o for cements early in the paragenetic sequence to 0 to 513c and 15 18o for cements which are interpreted to occur later in the paragenetic sequence this observation is consiste t with the influence of meteoric water on later stages of cement deposition in the cardium a unit considered to be marine and deposited well offshore on a shallow marine shelf the intrusion of meteoric water far offshore may be related to changes in sea level many variables must be accounted for but it is feasible using the estimated regional dip of the cardium at the time of deposition 0 005 for a 1 m drop in sea level to push the freshwater seawater interface seaward on the order of 100 km

oxygen and carbon isotopic composition of marine carbonate concretions an overview abstract compilation of stable isotope data 18o and 13c for marine calcite siderite and dolomite concretions from a large number of studies reveals consistent and unanticipated isotopic trends although many of the dolomites have 18o values that are compatible with precipitation from unaltered seawater at low temperatures most of the calcites and siderites are far too depleted in 12o for such an origin this is surprising as most of the concretions appear to have formed very early in the diagenetic history of the sediments often within several meters of the sediment water interface the most likely cause of the anomalously depleted oxygen values is a decrease in pore water 18o values during early diagenesis a result perhaps of a significant influx of meteoric water into the marine shelf environment or water mineral interaction e g precipitation of 18o enriched minerals the carbon isotopic field for dolomite is quite different from that for calcite and siderite highly positive 13c values are fairly common only for dolomites this indicates that while dolomite concretions often form in sediments where methanogenesis is rapid precipitation of calcite and siderite concretions is restricted to sediments where either n methanogenesis takes place or where methanogenesis is not extensive enough to generate highly positive pore fluid 13c values this variation in carbon isotopic composition among the different minerals suggests that the rates of organic carbon oxidation and sedimentation may control the mineralogy of carbonate concretions high organic carbon oxidation rates favor dolomite and lower oxidation rates favor calcite or siderite

seismic and geodetic signatures of fault slip at the slumgullion landslide natural laboratory 1 we tested the hypothesis that the slumgullion landslide is a useful natural laboratory for observing fault slip specifically that slip along its basal surface and side bounding strike slip faults occurs with comparable richness of aseismic and seismic modes as along crustal and plate scale boundaries our study provides new constraints on models governing landslide motion we monitored landslide deformation with temporary deployments of a 29 element prism array surveyed by a robotic theodolite and an 88 station seismic network that complemented permanent extensometers and environmental instrumentation aseismic deformation observations show that large blocks of the landslide move steadily at approximately centimeters per day possibly punctuated by variations of a few millimeters while localized transient slip episodes of blocks less than a few tens of meters across occur frequently we recorded a rich variety of seismic signals nearly all of which originated outside the monitoring network boundaries or from the side bounding strike slip faults the landslide basal surface beneath our seismic network likely slipped almost completely aseismically our results provide independent corroboration of previous inferences that dilatant strengthening along sections of the side bounding strike slip faults controls the overall landslide motion acting as seismically radiating brakes that limit acceleration of the aseismically slipping basal surface dilatant strengthening has also been invoked in recent models of transient slip and tremor sources along crustal and plate scale faults suggesting that the landslide may indeed be a useful natural laboratory for testing predictions of specific mechanisms that control fault slip at all scales

the characteristics of seismic signals produced by lahars and pyroclastic flows volcan de colima mexico abstract the general characteristics of seismic signals produced by pyroclastic flows generated by either the collapse of a lava dome or an eruptive column and lahars at volcan de colima mexico are discussed the paper concentrates on the 2004 2006 activity associated with and following the extrusion of andesitic block lava in october november 2004 it is shown that the duration of the broad band seismic records of pyroclastic flows lasts a few minutes while the duration of seismic records of lahars continues for tens of minutes or hours the spectra of seismic records produced by pyroclastic flows are characterized by lower peak frequencies around 3 4 hz than for lahars around 6 8 hz this difference in the frequency content together with the difference in the duration of seismic signals allows early diagnostic of the events in real time

geophysical monitoring of moisture induced landslides a review author s whiteley js chambers je uhlemann s wilkinson pb kendall jm abstract 2018 the authors geophysical monitoring of landslides can provide insights into spatial and temporal variations of subsurface properties associated with slope failure recent improvements in equipment data analysis and field operations have led to a significant increase in the use of such techniques in monitoring geophysical methods complement intrusive approaches which sample only a very small proportion of the subsurface and walk over or remotely sensed data which principally provide information only at the ground surface in particular recent studies show that advances in geophysical instrumentation data processing modeling and interpretation in the context of landslide monitoring are significantly improving the characterization of hillslope hydrology and soil and rock hydrology and strength and their dynamics over time this review appraises the state of the art of geophysical monitoring as applied to moisture induced landslides here we focus on technical and practical uses of time lapse methods in geophysics applied to monitoring moisture induced landslide the case studies identified in this review show that several geophysical techniques are currently used in the monitoring of subsurface landslide processes these geophysical contributions to monitoring and predicting the evolution of landslide processes are currently underrealized hence the further integration of multiple parametric and geotechnically coupled geophysical monitoring systems has considerable potential the complementary nature of certain methods to map the distribution of subsurface moisture and elastic moduli will greatly increase the predictive and monitoring capacity of early warning systems in moisture induced landslide settings

evidence for a paleoaquifer from early diagenetic siderite of the cardium formation alberta canada abstract the sedimentology and stratigraphy of the cretaceous cardium formation are generally interpreted as indicating an offshore shallow marine shelf environment of deposition however geochemical and isotopic data suggest that porewater salinity varied widely during early diagenesis for much of the cardium in cases with little or no evidence of subaerial exposure of the sediments this apparent conflict can be resolved by postulating infiltration of early meteoric water into these nearshore sediments behind a mobile mixing zone infiltration of meteoric water and movement of the interface may have been possible during any phase of basin formation whether transgression regression or stillstand evidence for the presence of this paleoaquifer is found in data from the early diagenetic s derite cements of the raven river allomember and carrot creek member of the cardium formation

analysis of seismic signals recorded on a prone to fall rock column vercors massif french alps summary a small aperture 40 m short period seismic array was installed during four months on the vercors massif western french alps at the top of a limestone column which collapsed one month and a half later during this monitoring period 193 seismic events were recorded by the seven seismometers of the array signal analysis yielded three main types of nearby seismic events to be identified from temporal and spectral characteristics microearthquakes single or multiple events individual block falls and rock falls it turned out that 60 per cent of the 193 events were classified as microearthquakes exhibiting distinct p and s waves while 17 per cent of these events remained unclassified out of the microearthquakes 40 events with a good signal to noise ratio were selected and processed p and s wave traveltimes were picked on the records and the inferred hypocentral distances agree with the two zones of the scarp exhibiting fresh ruptures after the fall polarization analysis of the 3 c records along with numerical simulations allowed discriminating between the two possible rupture mechanisms toppling and sliding shear rupture sliding was the predominant mode in the lower part of the column whereas traction rupture toppling affected the upper part finally the comparison between the ground motions recorded on the column and on the rock mass showed a systematic amplification on the column signal processing and numerical modelling both suggest that this amplification resulted from the excitation of the natural frequencies of the column and is particularly high 3 for microearthquakes occurring at the column to mass interface

ten years of debris flow monitoring in the moscardo torrent italian alps abstract field data on debris flows are of utmost importance for improving knowledge of these hazardous phenomena and for the development of attenuation measures in alpine basins debris flows generally occur with a frequency high enough to create serious risk to human settlements and transportation routes but too low to justify monitoring activity capable of providing enough data in a sufficiently short time the moscardo torrent a small stream in the eastern italian alps is an exception to this general situation since it displays a high frequency of debris flows commonly at least one event per year in 1989 this torrent was instrumented and the results of the following 10 years 1989 1998 of debris flow monitoring are presented with an analysis of collected data the equipment installed allowed measurement of rainfall flow stage and ground vibrations caused by debris flows other important debris flow variables that is mean front velocity peak discharge and flowing volume were estimated from instrumental records video pictures have proved to be useful for the visual interpretation of debris flow waves and have made it possible to estimate the surface velocity of debris flows recorded data are compared with other experimental data sets collected and documented worldwide advantages and shortcomings of different types of sensors are discussed with relevance both for research monitoring purposes and for possible use in debris flow warning systems

slope instabilities in dolomieu crater reunion island from seismic signals to rockfall characteristics 1 the seismic signals of hundreds of rockfalls within dolomieu crater piton de la fournaise volcano reunion island have been analyzed to investigate a possible link between physical rockfall generating processes and associated seismic signal features moreover indirect observation of rockfalls via the seismic signals they generate can provide useful data for studying volcanoes and the temporal variations of their structure an increase in the number of rockfall events and their volumes might be an indicator of structural weakness and deformation of the volcano associated with potential eruptive activity the study focuses on a 10 month period following the 6 april 2007 crater floor collapse within dolomieu crater from may 2007 to february 2008 for granular flows a scaling law is revealed between seismic energy and signal duration a semiempirical approach based on both analytical analysis and numerical simulation of these flows shows that a similar scaling law exists between the difference of potential energy computed for an event and its propagation times and also emphasizes the effect of local topography on this scaling law simulated and observed data were compared to evaluate the proportion of potential energy dissipated in the form of seismic waves and confirm a direct link between the seismic energy and potential energy of a given granular flow the mean ratio of seismic to potential energy is of the order of 10 4 comparable to the range of values observed in previous studies a simple method based on these ratios is proposed to estimate the volumes of rockfalls from their seismic signal observed seismic energy and the frequency of rockfalls decreased at the beginning of the studied period and reached a stable level in july thus suggesting a postcollapse relaxation time of dolomieu crater structure of about 2 months from seismic signal analysis which is confirmed by deformation data the total rockfall volume over the study period is estimated to be 1 85 mm3

array analysis using circular wave front geometry an application to locate the nearby seismo volcanic source summary the zero lag cross correlation technique used for array analysis in the hypothesis of plane waves has been modified to allow the wave front to be circular synthetic tests have been performed to check the capability of the method which returns the input test data when the source array distances are not greater than two or three times the array aperture for this distance range the method furnishes an estimate of the apparent velocity and the epicentral coordinates of the source for more distant sources the method becomes equivalent to that based on the planar wave approximation which gives an estimate of the backazimuth to the source and the apparent velocity the method has been applied to seismic data recorded at the active volcano located at deception island antarctica 35 volcanic long period events occurring in a small swarm were selected results show that the epicentres are close to the array between 0 4 and 2 km and aligned in a sw direction in agreement with one of the main directions of the fracture system of deception volcano

seismic monitoring of sechilienne rockslide french alps analysis of seismic signals and their correlation with rainfalls 1 in the french alps sechilienne rockslide is one of the natural phenomena that presents one of the highest levels of risk in terms of socioeconomical outcomes this rockslide has been active for a few decades and has been instrumented since 1985 the current very active volume of this rockslide is estimated to be up to 5 million m3 located on the border of a slowly moving mass reaching 50 100 million m3 the velocity of the most active zone reached 1 4 m yr in 2008 about twice the value of 2000 a seismic network was installed on this rockslide in may 2007 to supplement the monitoring system it has now recorded several thousand events mostly rockfalls but also hundreds of local and regional earthquakes which can be distinguished and classified from their signal characteristics rockfalls and microseismicity which occur in bursts of activity are found to be weakly but significantly correlated with rainfall rockfall occurrence increases linearly with precipitation with however strong fluctuations of the numbers of rockfalls per day for the same rainfall intensity no threshold was found for rainfall triggering with even 1 mm of rain being enough to trigger rockfalls rockfall activity starts almost immediately during a rainfall episode and lasts for several days after the rainfall rain also induces strong accelerations of the rockslide movement which also start quasi instantaneously and last for about a month

winter and summer temperatures of the early middle eocene of france from turritella δ18o profiles the mean annual range of temperature is from a climatological point of view at least as important as the mean annual temperature in order to examine intra annual temperature variations in the warm early cenozoic we have analyzed stable oxygen and carbon isotopes along the transect of growth on excellently preserved specimens of the gastropod turritella imbricataria and the bivalve venericardia imbricata from sedimentary rocks of early middle eocene age ca 46 ma in the paris basin turritella shell growth is fast throughout the year and the isotopic records give the first detailed information about early middle eocene seasonal variations the oxygen isotope profiles indicate winter temperatures of about 14 c and summer temperatures of up to 28 c i e a seasonality indistinguishable from the present situation but an annual temperature some 10 c higher our results contradict the opinion that the climate during this period was more equable than that of today

widespread nearshore and shallow marine deposition within the lower jurassic precipice sandstone and evergreen formation in the surat basin australia abstract in the surat basin of eastern australia the lower jurassic precipice sandstone and evergreen formation are a highly prospective reservoir seal pair for notional future carbon capture and storage however the succession remains poorly constrained from a paleodepositional standpoint and this has impacted the capacity to construct predictive reservoir models here we integrate sedimentological ichnological and palynological data from ten cores located across a large region of the northern and central basin to produce conceptual depositional models for the interval our analysis shows that the lower jurassic series consists of fifteen recurring sedimentary facies that are arranged into six facies associations braidplain lower delta plain subaqueous delta delta influenced shoreface tidally influenced shoreline and restricted marine shoals the facies associations occur in the context of large scale fluvio deltaic systems that occupied the basin these results are supported by ichnological indications of marine and brackish water a coastal suite of palynomorphs and marine palynomorphs including rare dinocysts acritarchs and copepod fragments the very low abundance of marine palynomorphs are confined to the upper portion of the evergreen formation and in combination with the sedimentology and ichnology suggest that marine influence increased through time as the basin was filled the elucidation of marine influenced deposition contravenes all but the most recent facies interpretations of the precipice sandstone and evergreen formation and suggests that the paleogeography of the mesozoic of eastern australia needs to be reconsidered importantly the nearshore and shallow marine depositional affinity has important implications for the size orientation and distribution of geobodies when building geologically realistic static reservoir models for dynamic flow simulation

glacial isostasy and long term crustal movements in fennoscandia with respect to lithospheric and asthenospheric processes and properties abstract the last glacial loading unloading cycle gave rise to a crustal deformation today seen as an elliptic uplift cone centered over the fennoscandian baltic shield with a maximum uplift of 830 m in the center and a surrounding subsidence trough the mass flow took place in a low viscosity asthenosphere in the order of 1020 poise the flexural rigidity was high in the order of 1025 nm the present uplift represents a linear uplift factor that may be driven by phase boundary displacements and or readjustments in the low velocity zones within the lower lithosphere the long term crustal movements represent deformations of similar geometry and shape indicating a strong influence from the shape of the lithosphere the egt profiles provide new and independent observational data that seem to be in perfect agreement with those obtained from crustal movements the downwarping of the lithosphere explains the repetition of similar geometry and shape of the crustal deformations it also explains the high flexural rigidity established the recording of a low viscosity asthenosphere confirms the conclusions drawn from the uplift area the absence of deformation of the lower boundary of the asthenosphere indicates that the loading unloading was fully compensated within the asthenosphere by horizontal flow hence confirming the model of the glacial isostatic deformation of morner 1979a 1980a

acoustic emission microseismic source location analysis for a limestone mine exhibiting high horizontal stresses a thin and rigid limestone roof and high horizontal stresses in an underground limestone mine have caused severe roof fall problems to help the mine address these problems an acoustic emission microseismic system was installed at the mine however the efficiency of this system was hampered by high background noise and inadequate source locations the focus of this research was therefore to resolve these problems the most beneficial outcome of this research was to demonstrate that the source location calculation at the mine could be improved through a comprehensive source location approach which includes digital filtering an absolute value based optimization method an advanced simplex location algorithm and reliability analysis

course and origin of the fennoscandian uplift the case for two separate mechanisms the classical glacial isostatic uplift paradigm of fennoscandia is in need of a thorough revision as to its course and origin the total uplift amounts to 830 m not 300 m the centre of uplift started to rise 13 000 bp not 9300 bp the uplift appears to be composed of two separate mechanisms one true glacial isostatic rebound and one linear uplift factor possibly representing a phase boundary adjustment calculations and modelling must treat these two factors independently which has not been the case

petrology and palaeoenvironmental significance of glaucony in the eocene succession at whitecliff bay hampshire basin uk following the investigations of odin and others into the distribution of green granules glaucony has been widely assumed to be a reliable indicator of a fully marine open shelf environment with a low sedimentation rate we have investigated the value of glaucony as a palaeoenvironmental indicator through an investigation of the pellets and their distribution and reworking in the predominantly brackish to shallow marine tertiary sediments of the hampshire basin together with a re evaluation of the sedimentology glaucony has apparently formed in situ in all lithofacies from shallow marine to estuarine of the three highest glaucony concentrations all dominated by in situ glaucony two occur within highstand system tracts the third is at a sequence boundary several important surfaces do not have more than a few percent glaucony with very variable proportions of mature and in situ pellets the correlation between glaucony concentration and sequence stratigraphy is most obvious in the london clay and wittering formations where least reworking of pellets has occurred in the barton group there are no major concentrations of glaucony at any of the important stratal surfaces we believe this more random glaucony distribution is due to limited glaucony formation and reworking of older glaucony in these sediments ideal conditions for glaucony formation are interpreted to have been fully marine 10 30 m water depth a warm temperature plus low sedimentation rate with periodic winnowing to concentrate the pellets although most of these conditions for glaucony formation occurred in the selsey formation and barton group a factor or factors mitigated against glauconitization we suggest that this was lowering of the water temperature the london clay and wittering formations were deposited relatively rapidly 50 60 m ma 1 and include intervals of estuarine sedimentation both factors that we believe inhibited glaucony formation glaucony maturity reflects the minimum length of time spent in surface sediments close to the oxic sub oxic interface point count data and chemical data for glaucony indicate widespread reworking and an overall increase in reworking with time possibly due to uplift on the isle of wight monocline the apparently wide range of conditions in which glaucony will form and the frequency with which it is reworked suggest that it is a less useful indicator palaeo environmental indicator than is commonly supposed

an attempt to define a neotectonic period for central and northern europe the neotectonic period is the youngest period of tectonic evolution and extends up to the present the beginning of the neotectonic period during the cenozoic may be regarded as having begun when characteristic changes in the tectonic evolution of a region of interest have occurred for the last time changes in the different tectonic facets which characterize the evolution of a region need not be simultaneous and hence the times of the last change may differ between facets this leads to the definition of a transitional time interval wherein elements of both the palaeotectonic and neotectonic period are present the length of this transitional time interval depends on the regional geological evolution where a broad transitional time interval exists the beginning of the neotectonic period may be defined by the earliest time marker by when most of the characteristic changes of the tectonic evolution of the region had occurred

insights into rock ice avalanche dynamics by combined analysis of seismic recordings and a numerical avalanche model 1 rock ice avalanches larger than 1 106 m3 are high magnitude low frequency events that may occur in all ice covered high mountain areas around the world and can cause extensive damage if they reach populated regions the temporal and spatial evolution of the seismic signature from two events was analyzed and recordings at selected stations were compared to numerical model results of avalanche propagation the first event is a rock ice avalanche from iliamna volcano in alaska which serves as a natural laboratory with simple geometric conditions the second one originated on aoraki mt cook new zealand southern alps and is characterized by a much more complex topography a dynamic numerical model was used to calculate total avalanche momentum total kinetic energy and total frictional work rate among other parameters these three parameters correlate with characteristics of the seismic signature such as duration and signal envelopes while other parameters such as flow depths flow path and deposition geometry are well in agreement with observations the total frictional work rate shows the best correlation with the absolute seismic amplitude suggesting that it may be used as an independent model evaluation criterion and in certain cases as model calibration parameter the good fit is likely because the total frictional work rate represents the avalanche s energy loss rate part of which is captured by the seismometer deviations between corresponding calculated and measured parameters result from site and path effects which affect the recorded seismic signal or indicate deficiencies of the numerical model the seismic recordings contain additional information about when an avalanche reaches changes in topography along the runout path and enable more accurate velocity calculations the new concept of direct comparison of seismic and avalanche modeling data helps to constrain the numerical model input parameters and to improve the understanding of rock ice avalanche dynamics

the use of varved clay chronology for dating paleoseismic events the erstavik record in the stockholm area south sweden abstract geological structures suggest that the fennoscandian shield was subjected to a higher seismicity at the end of the last glaciation than today this article demonstrates the use of varved clay chronology for dating paleoseismic events it is argued that the deposited annually layered glacial varves were sensitive to past ground movements in the stockholm area the erstavik varved clay chronology suggests four paleoseismic events a first i dating from varve year 10 473 to 10 468 bp a second ii 10 451 to 10 445 bp a third iii 10 429 to 10 425 bp and a fourth iv 10 409 to 10 404 bp in de geer s old 1940 chronology the first i dating corresponds with 1117 to 1112 the second ii with 1095 to 1089 the third iii with 1073 to 1069 and the fourth iv with 1053 to 1048 the most pronounced event was the one at around varve year 10 429 bp varve 1073 in de geer s old chronology the recurrence time of about 20 years suggests a totally different seismic regime at the time of deglaciation than what exists today it coincided with the period of maximum isostatic uplift the complexity of the varved clay response to seismic events is also discussed

submarine holocene sedimentary disturbances in the olkiluoto area of the gulf of bothnia baltic sea a case of postglacial palaeoseismicity abstract high resolution echo soundings were used to study the fault activity in the olkiluoto area of the gulf of bothnia southwestern finland echo sounding profiles in holocene submarine sediments show normal faults structures related to gas or groundwater seepage submarine slides and slumps and debris flow type structures the faults and other disturbance structures occur along two bedrock lineaments all faults occur at the same stratigraphical level whose age is estimated at 10 700 calendar years bp 9500 radiocarbon years bp it is suggested that their movement has been triggered by palaeoseismic event s when the late weichselian ice sheet was retreating from the site and bedrock stresses were released through lineaments and fracture zones these are the first observations of postglacial fault movements in quaternary sediments from southern finland but the timing of these movements is contemporaneous with the incidence of postglacial bedrock faulting 9000 10 000 radiocarbon years bp in northern fennoscandia the origin of the gas groundwater seepages remains unclear their reflections in the echo sounding profiles imply that part of the gas is derived from the organic bearing litorina and recent gyttja clays however at least some part of the gas is derived from the bedrock deep gas

geochemistry of carbonate cements in the sag river and shublik formations triassic jurassic north slope alaska implications for the geochemical evolution of formation waters carbonate cements calcite siderite dolomite and ankerite formed throughout the diagenetic history of the sag river and shublik formations the trace element and isotopic geochemistry of these cements varies as a function of the timing of precipitation earliest calcites formed prior to significant compaction of the sediment are relatively enriched in mg up to 4 4 mol and have 87sr 86sr values mean 0 707898 compatible with the original marine pore waters later calcites are relatively fe rich up to 5 0 mol and are characterized by increasing 87sr 86sr values up to 0 712823 and sr content with decreasing age the fe content of zoned siderite and dolomite ankerite rhombs increases towards the outside of the rhombs i e increasing fe content with decreasing age these geochemical variations appear principally to result from changes in pore water chemistry during diagenesis the increase in 87sr 86 sr and sr content of the cements is most likely due to interaction between pore waters and 87 sr rich clay and possibly feldspar in ellesmerian mudrocks whole rock 87sr 86 sr signatures for the mudrocks are 0 716 pore water fe2 concentration was probably controlled by diagenetic alterations involving fe bearing minerals e g pyrite precipitation a reconnaissance examination of carbonate cements in the overlying kingak shale indicates that similar alterations occurred in the kingak the low 18 o value of some calcite cements 11 96 pdb suggests that an influx of meteoric water may have occurred in the mid neocomian though the low value could also result from an abnormally high geothermal gradient associated with mid neocomian rifting

evolution of the toarcian early jurassic carbon cycle and global climatic controls on local sedimentary processes cardigan bay basin uk the late early jurassic toarcian stage represents the warmest interval of the jurassic period with an abrupt rise in global temperatures of up to 7 c in mid latitudes at the onset of the early toarcian oceanic anoxic event t oae 183 ma the t oae which has been extensively studied in marine and continental successions from both hemispheres was marked by the widespread expansion of anoxic and euxinic waters geographically extensive deposition of organic rich black shales and climatic and environmental perturbations climatic and environmental processes following the t oae are however poorly known largely due to a lack of study of stratigraphically well constrained and complete sedimentary archives here we present integrated geochemical and physical proxy data high resolution carbon isotope data 13c bulk and molecular organic geochemistry inorganic petrology mineral characterisation and major and trace element concentrations from the biostratigraphically complete and expanded entire toarcian succession in the llanbedr mochras farm borehole cardigan bay basin wales uk with these data we 1 construct the first high resolution biostratigraphically calibrated chemostratigraphic reference record for nearly the complete toarcian stage 2 establish palaeoceanographic and depositional conditions in the cardigan bay basin 3 show that the t oae in the hemipelagic cardigan bay basin was marked by the occurrence of gravity flow deposits that were likely linked to globally enhanced sediment fluxes to continental margins and deeper marine shelf basins and 4 explore how early toarcian tenuicostatum and serpentinum zones siderite formation in the cardigan bay basin may have been linked to low global oceanic sulphate concentrations and elevated supply of iron fe from the hinterland in response to climatically induced changes in hydrological cycling global weathering rates and large scale sulphide and evaporite deposition

neotectonics and paleoseismicity within the stockholm intracratonal region in sweden abstract a number of sites with fresh faults and fractures have been mapped in detail their postglacial and sometimes late glacial age is confirmed they form simple and similar patterns consistent with stress release due to a combination of acting forces they are associated with the peak rate of glacial isostasy and increased strain rates by two orders of magnitude they often cut straight across bedrock hills between so called weak zones the fault throws correspond to approximately magnitude 7 on the richter scale sedimentary and morphological data confirm the seismo tectonic origin newly discovered large scale network of crossing faults is found to have changed the course of the stockholm esker in a way that reveals at least two major seismo tectonic events this is consistent with paleoseismic events of magnitude 7 or more

location of seismic signals associated with microearthquakes and rockfalls on the sechilienne landslide french alps the sechilienne rockslide in the french alps has recently been instrumented with three seismic arrays this network has recorded numerous rockfalls and local microearthquakes because the media is highly fractured it is difficult to identify and pick first arrivals beam forming methods were therefore used to locate these events the method has been adapted to take into account the heterogeneity of seismic wave velocities the location accuracy has been estimated to be about 50 m for epicenters by applying the method to calibration shots depth is less constrained due to uncertainties on the velocity model and due to the seismic network geometry this method of location has then been applied to rockfalls and microearthquakes most rockfalls initiate in the most active part of the rockslide called les ruines the others are located on a recent eroded area aside from les ruines the network also allows the estimation of the rockfall trajectory and propagation speed finally 55 microearthquakes have been located within two zones microearthquakes are located within the first 250 m below the surface most microearthquakes are located in les ruines the most active part of the rockslide where the velocity has increased from 0 5 m yr in 1996 to 1 4 m yr in 2008 these events are located close to three faults that delimit a mass of about 3 6 million m3 other events are located close to the summital scarp in a zone moving at a few centimeters per year the western part of the rockslide which moves more slowly did not produce any event large enough to be detected simultaneously by all stations this seismic monitoring suggests that only a very small fraction of the deformation is released through seismic events

seismic monitoring of soft rock landslides the super sauze and valoria case studies this work focuses on the characterization of seismic sources observed in clay shale landslides two landslides are considered super sauze france and valoria italy the two landslides are developed in reworked clay shales but differ in terms of dimensions and displacement rates thousands of seismic signals have been identified by a small seismic array in spite of the high seismic attenuation of the material several detection methods are tested a semi automatic detection method is validated by the comparison with a manual detection seismic signals are classified in three groups based on the frequency content the apparent velocity and the differentiation of p and s waves it is supposed that the first group of seismic signals is associated to shearing or fracture events within the landslide bodies while the second group may correspond to rockfalls or debris flows a last group corresponds to external earthquakes seismic sources are located with an automatic beam forming location method sources are clustered in several parts of the landslide in agreement with geomorphological observations we found that the rate of rockfall and fracture events increases after periods of heavy rainfall or snowmelt the rate of microseismicity and rockfall activity is also positively correlated with landslide displacement rates external earthquakes did not influence the microseismic activity or the landslide movement probably because the earthquake ground motion was too weak to trigger landslide events during the observation periods

paleoseismicity and geodynamics in sweden abstract paleoseismicity denotes past pre instrumental earthquakes as recorded by bedrock structures morphological features and sedimentological criteria glacial varves eskers and deltas are excellent records of paleoseismic events data from sweden are presented faults fractures and various types of sedimentary disturbances of late pleistocene and holocene age frequently occur it is concluded that the seismic activity was very intensive in connection with the peak rates of glacial isostatic uplift and that this was a natural effect of the geodynamic processes operating

spherulitic siderites in the holocene coastal deposits of korea eastern yellow sea elemental and isotopic composition and depositional environment abstract siderite concretions are recovered from both freshwater unit ii and tidal unit i deposits in the holocene macrotidal flat of kyunggi bay west coast of korea siderites from both units show a spherulitic and well rounded texture and well developed equant rhombs on the external surfaces the size of the concretions in unit ii 50 150 m in diameter is normally larger than that in unit i 10 20 m the siderites in unit ii are chemically pure and highly enriched in fe whereas those of unit i are relatively impure and distinctly zoned demarcating high mn up to 69 1 mol in the core and high fe up to 75 9 mol in the margin within siderites of unit i substitution for fe by ca and mg reaches up to 20 3 mol mean 15 1 mol and 16 1 mol mean 12 6 mol respectively bulk 18 o values 0 7 to 1 3 peedee belemnite pdb for siderites in unit i are relatively higher than those 7 1 to 0 5 pdb in unit ii regardless of units siderite 13 c values 21 3 to 11 2 pdb are persistently low indicating microbially mediated precipitation at shallow burial depth extensive mn ca and mg substitution coupled with enrichment of 18 o in the siderites of unit i seems to reflect marine influence during the holocene transgression the occurrence of early diagenetic siderites provides supporting evidence on the depositional environment marine vs non marine of the holocene muddy coastal deposits of korea eastern yellow sea

early eocene climatic optimum environmental impact on the north iberian continental margin the early eocene climatic optimum which constituted the peak of the long term early cenozoic global warming had a significant impact on the environmental evolution of terrestrial and oceanic areas surprisingly however its influence on continental margins is poorly known new insights are provided from a sedimentological stable isotope mineralogical and micropaleontological study of an 1100 m thick lower middle eocene deep marine succession that accumulated on the north iberian continental margin the early eocene climatic optimum is represented by a 410 m thick interval characterized by scarcity of hemipelagic limestones abundance of dark marls which record a reduction in calcium carbonate content and an increase in kaolinite and the occurrence of conspicuous red layers with high siderite and pyrite content series of stratigraphically significant events frame the early eocene climatic optimum based on this analysis the environmental influence of the early eocene climatic optimum started at 52 6 ma and lasted 2 3 m y its onset is marked by rapid drops in 13c and 18o which record the addition of 13c depletedcarbon into the ocean atmosphere system for 80 k y and a concomitant warming a hotter climate and a perennial rainfall regime increased the supply of terrestrial clays organicmatter and iron oxides into the sea eventually these changes affected the deepsea bottom 270 k y after the onset of the early eocene climatic optimum creating conditions in which opportunistic benthic foraminifera thrived and leading to increased methanogenesis in the subsurface which caused the formation of siderite a subsequent gradual recovery culminated abruptly at 50 3 ma with a global cooling episode which is locally recorded by the accumulation of lowstand resedimentation deposits 2015 geological society of america

the storegga slides evidence from eastern scotland for a possible tsunami abstract the second storegga slide on the continental slope off western norway has been dated at between 8000 and 5000 yrs b p a prominent sand layer in flandrian holocene deposits along the coast of eastern scotland and dated at approximately 7000 yrs b p may have been deposited by a tsunami generated by the slide the altitude and stratigraphy of the layer allow estimates to be made of the magnitude of the earthquake which initiated the slide

isotopically heavy oxygen containing siderite derived from the decomposition of methane hydrate authigenic siderite from the miocene and pliocene sediments of the blake outer ridge formed in a methane fermentation zone in equilibrium with anomalously heavy oxygen water as evidenced by its heavy carbon 1 6 to 12 5 13c and heavy oxygen 0 1 to 7 9 18o values blake outer ridge sediments are impregnated with methane hydrate which is generally enriched in 18o relative to ambient water this suggests that decomposition of methane hydrate and subsequent release of large amounts of methane and heavy oxygen water affected the formation of the 18o enriched siderite gas hydrate reaction in sediments is an important process for causing a dramatic variation of oxygen isotopic composition of the interstitial water and of authigenic carbonates formed during burial diagenesis

seismic signals of snow slurry lahars in motion 25 september 2007 mt ruapehu new zealand 1 detection of ground shaking forms the basis of many lahar warning systems seismic records of two lahar types at ruapehu new zealand in 2007 are used to examine their nature and internal dynamics upstream detection of a flow depends upon flow type and coupling with the ground 3 d characteristics of seismic signals can be used to distinguish the dominant rheology and gross physical composition water rich hyperconcentrated flows are turbulent common inter particle and particle substrate collisions engender higher energy in cross channel vibrations relative to channel parallel plug like snow slurry lahars show greater energy in channel parallel signals due to lateral deposition insulating channel margins and low turbulence direct comparison of flow size must account for flow rheology a water rich lahar will generate signals of greater amplitude than a similar sized snow slurry flow

laboratory study of the underground sound generated by debris flows 1 this experimental study investigates the underground sound generated by different kinds of rock motions that occur in debris flows the experiments were divided into two parts the first part consisted of measuring the main characteristics of the underground sound caused by friction of a rock rubbed against a bed of gravel and of that caused by a free falling rock hitting a similar bed of gravel in the second part a hydrophone was installed at the bottom of a laboratory channel to measure the underground sound of debris flows in that channel the sound signals were analyzed using both the fast fourier transform and the gabor transform to represent the signals in both the frequency and time frequency domains the measurement results reveal that the frequency of the sound generated by the rock gravel bed friction is relatively low being mostly between 20 and 80 hz in contrast the frequency range of the collision sound is relatively higher between 10 and 500 hz finally the frequency of the underground sound caused by the debris flows in the flume is in the range of 20 300 hz

diagenetic clinoptilolite and opal ct from the middle eocene wittering formation isle of wight u k abstract thinly interbedded estuarine sandstones and mudstones in the middle eocene wittering formation bracklesham group isle of wight contain authigenic clinoptilolite opal ct and possibly authigenic smectite over a thickness of 8 5 m the clinoptilolite and opal ct cements have resulted in these beds being the only ones tightly cemented in the wittering formation the rest being soft sands and muds the unit contains abundant siliceous sponge spicules many of which are preserved as voids and were the likely source of the opal ct the presence of an organic rich rooted paleosol histosol immediately overlying the unit is believed to have contributed significantly to the early diagenetic history of the estuarine sediments in particular the formation of zeolite although the ph and dissolved silica of unmodified seawater are too low for zeolite formation high concentrations of dissolved silica are believed to have resulted from dissolution of siliceous sponge spicules opal a and formation of silica organic acid complexes organic acid dissolution of feldspars absent from the zeolite bearing interval is the most probable source of alumina and cations for zeolite formation ree data show that volcanic ash was never present and cannot therefore have been the source of the zeolite this investigation therefore demonstrates a novel route by which the pore fluid chemistry required for zeolite formation can be achieved

instability conditions of marly hillslopes towards landsliding or gullying the case of the barcelonnette basin south east france abstract black marl hillslopes in the french alps are strongly affected either by mass movements or by gully erosion due to their susceptibility to weathering processes this paper presents experimental data geomorphological geotechnical geomechanical and hydrological on the parameters of the material of three well known earthflows and of the two stratigraphic parts of the callovo oxfordian black marl the main objectives are to define the geomechanical behaviour of the various formations using different characterisations grain size distribution mineralogy retention capacity consolidation test direct shear test and triaxial test and to demonstrate how such soils can affect the stability of natural slopes particular care must be taken when interpreting the geomechanical tests on this evolving and very heterogeneous clay rich material there are strong relationships between the parent rock and the landslide materials this paper presents a conceptual model of the development of strength over a period of time and investigates the parameters of the material for use in slope stability analysis and risk assessment

ambient seismic noise monitoring of a clay landslide toward failure prediction given that clay rich landslides may become mobilized leading to rapid mass movements earthflows and debris flows they pose critical problems in risk management worldwide the most widely proposed mechanism leading to such flow like movements is the increase in water pore pressure in the sliding mass generating partial or complete liquefaction this solid to liquid transition results in a dramatic reduction of mechanical rigidity in the liquefied zones which could be detected by monitoring shear wave velocity variations with this purpose in mind the ambient seismic noise correlation technique has been applied to measure the variation in the seismic surface wave velocity in the pont bourquin landslide swiss alps this small but active composite earthslide earthflow was equipped with continuously recording seismic sensors during spring and summer 2010 an earthslide of a few thousand cubic meters was triggered in mid august 2010 after a rainy period this article shows that the seismic velocity of the sliding material measured from daily noise correlograms decreased continuously and rapidly for several days prior to the catastrophic event from a spectral analysis of the velocity decrease it was possible to determine the location of the change at the base of the sliding layer these results demonstrate that ambient seismic noise can be used to detect rigidity variations before failure and could potentially be used to predict landslides

microbial influence on the oxygen isotopic composition of diagenetic siderite abstract numerous early diagenetic siderite concretions previously described have been interpreted as the results of microbially mediated reactions interpretation of oxygen isotope data for such material requires an understanding of the effect of temperature on fractionation processes however whilst equilibrium fractionation of oxygen isotopes between siderite and water has been measured down to 33 c extrapolation to lower temperatures may be invalid furthermore inorganic measurements may not be applicable to microbial systems the specific iron reducing microorganism geobacter metallireducens has been cultured anaerobically in the laboratory using acetate as an organic substrate and amorphous feooh as an electron acceptor the acetate is oxidised to co2 with concurrent iron reduction and extracellular siderite precipitation rhombohedral siderite crystals up to 25 m in size have been precipitated over a range of temperatures 18 40 c stable isotopic analysis of these crystals and the solutions from which they precipitate shows that this microbial precipitation of siderite has an associated isotopic fractionation different from the published equilibrium and which is not simply a function of temperature in all cases 18o values of siderite are lower than predicted by inorganic equilibrium fractionation data this may explain the numerous anomalously low 18o values reported for early diagenetic marine siderites and previously attributed to mechanisms such as mixing with meteoric water sediment water interaction recrystallisation or variable isotopic fractionation despite a lack of supporting evidence

geochemistry of early siderite cements from the eocene succession of whitecliff bay hampshire basin u k abstract siderite cements in the eocene of whitecliff bay hampshire basin u k occur in a range of depositional facies and morphological associations most siderites are associated with in situ glaucony or occur beneath conspicuous lithological breaks these associations illustrate the importance of slow deposition for early diagenetic carbonate precipitation siderite in the eocene sediments of whitecliff bay is impure and in many cases comprises zoned crystals with an overall decrease in substitution of ca mg and mn for fe from crystal core to rim trends in ca mg and mn from early to later siderite vary between samples with no evident environmental control siderite concretions without calcite cement occur only beneath lithological breaks where meteoric water may have been introduced precipitation temperatures have been calculated from siderite 18o data and are based on the assumption that precipitation occurred from seawater these temperatures are reasonable for typical microbial siderite precipitated in marine sediment but are slightly low for marine siderite where there may have been meteoric overprinting if the precipitation temperature for siderite cements is assumed from 18o data for time equivalent biogenic carbonate rather than the composition of the precipitating fluid the calculated isotopic composition of the precipitating fluid is generally compatible with the inferred marginal marine depositional environments