simplified models of spreading flow of dry granular material shallow flow integrated numerical models of landslide and avalanche motion have recently experienced rapid development an important aspect of model development is verification to show that models

do moderate magnitude earthquakes generate seismically induced ground effects the case study of the m w 5 16 29th december 2013 matese earthquake southern apennines italy seismically induced ground effects characterize moderate to high magnitude seismic events whereas they are not so common during seismic sequences of low to moderate magnitude a low to moderate magnitude seismic sequence with a m w 5 16 0 07 main event occurred from december 2013 to february 2014 in the matese ridge area in the southern apennines mountain chain in the epicentral area of the m w 5 16 main event which happened on december 29th 2013 in the southeastern part of the matese ridge field surveys combined with information from local people and reports allowed the recognition of several earthquake induced ground effects such ground effects include landslides hydrological variations in local springs gas flux and a flame that was observed around the main shock epicentre a coseismic rupture was identified in the sw fault scarp of a small sized intermontane basin mt airola basin to detect the nature of the coseismic rupture detail scale geological and geomorphological investigations combined with geoelectrical and soil gas prospections were carried out such a multidisciplinary study besides allowing reconstruction of the surface and subsurface architecture of the mt airola basin and suggesting the occurrence of an active fault at the sw boundary of such basin points to the gravitational nature of the coseismic ground rupture based on typology and spatial distribution of the ground effects an intensity i vii viii is estimated for the m w 5 16 earthquake according to the esi 07 scale which affected an area of at least 90 km2

crustal deformations in the epicentral area of the west bohemia 2008 earthquake swarm in central europe 1 in west bohemia central europe during october 2008 an earthquake swarm of 25 000 shocks with a maximum event of ml 3 7 3 8 occurred at depths of 7 11 km in 2007 annual gps campaigns were launched during the co seismic phase displacements of a few centimeters were detected at gps sites maximum displacement was revealed at the kopa site which subsided by 167 mm the epicentral area is covered by eluvium of 4 10 m thick and is located in undulating pastures and well forested valleys where visible surface soil effects could not be observed to test possible fault manifestations rough geomorphologic geoelectric and geochemical surveys were performed gps and seismic data with geologic materials were used to build a forward model for surface displacements crustal deformations and shear and normal stress fields the fields enabled us to better determine crustal deformations and stresses that appeared within the seismic cycle during the pre co and post seismic phases during the co seismic phase modeled fault motions along n s faults located within the epicentral zone reached 0 6 1 mm day possible structural block rotations were comprised of these motions a dominant role for stress accumulation release and relaxation was assigned to the marianske lazn fault zone and the nov kostel zone strain loads slowly and when local pt conditions with an action of deep magmatic fluids reach instability the strain is released and stress balancing occurs the process leads to the reversible motions known for silent earthquakes a forward crustal deformation model for west bohemia is also presented within

estimation of lahar flow velocity on popocatepetl volcano mexico during 1997 and 2001 two lahars took place in the tenenepanco and huiloac gorges on the northeastern sector of the popocatepetl volcano in mexico these lahars were the result of volcanic activity characterized by a pyroclastic fall and flow the lahars were triggered by the mass failures produced hours after the eruption the well known superelevation technique commonly used in this kind of study was applied to infer the lahar s mean velocity estimations show a broad flow velocity range of 1 3 13 8 m s depending on the following geomorphological parameters channel depth and slope peak discharge and distance from the initial source these results were compared with lahar velocities from mount st helens 1980 and nevado del ruiz 1985 which were obtained by the same superelevation technique according to the data the lahars from nevado del ruiz and popocatepetl were triggered by similar conditions while at mount st helens they were the result of the conversion of a pyroclastic surge cloud actually the mount st helens lahars were almost twice as fast as the ones at nevado del ruiz and popocatepetl this observation shows the importance of the lahars genesis in that the pyroclastic surge clouds produce faster lahars than do pyroclastic falls such results should be taken into account in lahar risk assessment studies for communities located near active volcanoes 2007 elsevier b v all rights reserved

fan surface evidence for debris flow avulsion controls and probabilities saline valley california debris flow fans form by shifts of the active channel termed avulsions field and experimental evidence suggest that debris flow avulsions may be induced by depositional lobes that locally plug a channel or super elevation of the channel bed above the surrounding fan surface by analogy to fluvial fans to understand debris flow avulsion processes we differentiate between these controls by quantifying the spatial distribution of debris flow lobe and channel dimensions along with channel bed super elevation on nine debris flow fans in saline valley california usa channel beds are generally super elevated by 2 5 channel depths above the fan surface and locally by more than 7 channel depths thereby substantially exceeding super elevation on fluvial fans depositional lobe thickness and channel depth decrease with distance from the fan apex although both are highly variable across the fans median channel depths roughly correspond to the 50 75th percentiles of lobe thicknesses while minimum channel depths roughly correspond to the 10 25th percentiles in contrast the thicknesses of lobes that have triggered avulsions roughly equal local channel depths and are on average twice as thick as the local median lobe thickness the spatial correspondence between avulsion locations and thick lobe deposits and the lack of correlation with channel bed super elevation leads us to infer that avulsions on these fans are mostly caused by thick lobes forming channel plugs although results may vary with climatic and tectonic setting our findings indicate that avulsion hazard assessment on populated fans should include mapping and monitoring of channel depths relative to typical deposit thicknesses on a given fan

surface rupture associated with a 5 3 mb earthquake the 5 april 1986 cuzco earthquake and kinematics of the chincheros quoricocha faults of the high andes peru abstract the shallow mb 5 3 1986 earthquake that affected the cuzco region reactivated the 18 km long chincheros qoricocha faults in the central part of the cuzco fault system although the event has a moderate magnitude clear surface ruptures were observed to total 3 km in length with maximum 10 cm normal displacements fault kinematics related to the earthquake analyzed where the qoricocha fault had a maximum surface fault displacement is in agreement with roughly n s extension the normal fault mechanism proposed for this earthquake is compatible with the surface kinematic analysis seismic activity prior to the 1986 earthquake is deduced from analysis of holocene scarps trench exposures give evidence for at least three fault displacements suggesting an average recurrence interval of the order of a few thousand years for surface rupturing seismic events these fault reactivations with vertical displacement ranging from 0 6 to 2 m were related to seismic events of mw magnitude probably ranging from 5 8 to 6 9 structural analyses of holocene faults indicate that the chincheros qoricocha fault activity was related to roughly n s trending extension characterized by a horizontal n s trending 3 axis and a vertical 1 axis the n s extensional tectonics that controlled the holocene and 1986 chincheros qoricocha fault activity are the typical deformational pattern of the peruvian high andes and seem to be in agreement with compensated high topography

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

distribution and occurrence of aliphatic acid anions in deep subsurface waters abstract this study reports 144 new analyses of short chain aliphatic acid anions acetate propionate butyrate and valerate in formation waters from eight localities eastern venezuelan basin denver basin eastern green river basin red desert and washakie basins wamsutter arch san juan basin piceance basin raton basin gulf coast basin and the western overthrust reservoir temperature does not predict total or relative abundance of aliphatic acid anions but does predict maximum total concentrations of these species maximum concentrations increase to 90 c above 90 c maximum concentrations decrease above 250 c maximum concentrations should not exceed 1 mg 1 the general order of dominance is acetate propionate butyrate valerate but for coal associated waters is propionate acetate butyrate valerate lack of longer chain aliphatic acid anion dominance over acetate at low reservoir temperatures may suggest hydrologie communication with deeper reservoirs

an assessment of source parameters of earthquakes in the cordillera of the western united states abstract source parameters for 50 earthquakes occurring between 1915 and 1988 have been used to examine the faulting characteristics of magnitude 5 5 to 7 8 earthquakes within the western u s cordillera an area extending from the eastern sierra nevada to the great plains and from northwestern montana to trans pecos texas source parameters used in this study include seismic information from first motion analyses body and surface waveform modeling geodetic studies and geological studies of surface faulting the principal results of this analysis include 1 all earthquakes occurred on faults dipping 38 or more and no evidence for listric of low angle planar faulting was found 2 all m 7 0 earthquakes occurred at depths 12 km and were composed of multiple subevents 3 most earthquakes 70 per cent had unilateral ruptures and 4 no individual subevent had a rupture length 21 km

flow of variably fluidized granular masses across three dimensional terrain 1 coulomb mixture theory rock avalanches debris flows and related phenomena consist of grain fluid mixtures that move across three dimensional terrain in all these phenomena the same basic forces govern motion but differing mixture compositions initial conditions and boundary conditions yield varied dynamics and deposits to predict motion of diverse grain fluid masses from initiation to deposition we develop a depth averaged three dimensional mathematical model that accounts explicitly for solid and fluid phase forces and interactions model input consists of initial conditions path topography basal and internal friction angles of solid grains viscosity of pore fluid mixture density and a mixture diffusivity that controls pore pressure dissipation because these properties are constrained by independent measurements the model requires little or no calibration and yields readily testable predictions in the limit of vanishing coulomb friction due to persistent high fluid pressure the model equations describe motion of viscous floods and in the limit of vanishing fluid stress they describe one phase granular avalanches analysis of intermediate phenomena such as debris flows and pyroclastic flows requires use of the full mixture equations which can simulate interaction of high friction surge fronts with more fluid debris that follows special numerical methods described in the companion paper are necessary to solve the full equations but exact analytical solutions of simplified equations provide critical insight an analytical solution for translational motion of a coulomb mixture accelerating from rest and descending a uniform slope demonstrates that steady flow can occur only asymptotically a solution for the asymptotic limit of steady flow in a rectangular channel explains why shear may be concentrated in narrow marginal bands that border a plug of translating debris solutions for static equilibrium of source areas describe conditions of incipient slope instability and other static solutions show that nonuniform distributions of pore fluid pressure produce bluntly tapered vertical profiles at the margins of deposits simplified equations and solutions may apply in additional situations identified by a scaling analysis assessment of dimensionless scaling parameters also reveals that miniature laboratory experiments poorly simulate the dynamics of full scale flows in which fluid effects are significant therefore large geophysical flows can exhibit dynamics not evident at laboratory scales

debris flow generated tsunamis and their dependence on debris flow dynamics abstract debris flow generated tsunamis can be extremely dangerous for lakeside settlements and infrastructure debris flow composition strongly affects debris flow thickness and velocity and therefore also the generated tsunami this interaction is however poorly understood we investigate the effects of debris flow volume composition gravel sand clay water and subaerial outflow slope on wave celerity and amplitude in a small scale physical model consisting of an inclined outflow channel which transits into a three dimensional water reservoir we find that upon debouching a debris flow pushes the water forward until wave celerity exceeds subaqueous debris flow velocity i e froude number wave celerity has the strongest relation with debris flow velocity debris flow velocity increases with increasing water and clay content up to 22 which both lubricate the flow far field leading wave amplitude has the strongest relation with debris flow momentum velocity times effective mass which is mostly a function of debris flow thickness water and clay content we test the applicability of published semi empirical equations for predicting tsunami amplitude generated by dry landslides and show that they are to some extent also applicable to debris flow potential scale effects especially considering the smallest waves and water depths could influence the applicability of these predictors and translation of the results to the field scale our results demonstrate the importance of debris flow composition on tsunami generation and evolution and thus the necessity of including flow composition in predictive simulation models

source mechanisms of three moderate california earthquakes of july 1986 abstract we studied the source processes of three moderate size earthquakes in california the m s 6 0 event of july 8 1986 near palm springs the m s 5 8 shock of july 13 1986 offshore of oceanside and the m s 6 2 event of july 21 1986 in the chalfant valley on the east side of the sierra nevada the centroidal source parameters are estimated by inversion of long period p and sh waves recorded at teleseismic distances by seismographs of worldwide networks a more detailed description of the source is then obtained by analyzing broadband seismograms the north palm springs earthquake had a simple rupture process most of the seismic moment was released in the first 3 sec in a single step the strike of the source fault plane follows the average trend of the banning fault and its dip agrees with the dip of the fault plane delineated by the aftershocks the faulting mechanism of the main shock is right lateral strike slip with a sizable reverse component that is consistent with uplift north of the banning fault the earthquake offshore of oceanside had a slightly more complex rupture process the far field source time function consists of two pulses that represent the release of most of the moment in the first 3 sec the source mechanism indicates reverse faulting with the compressional axis trending northeast almost perpendicular to the trend of mapped faults offshore the event does not appear to be associated with major mapped faults in the area but the strike of one of the nodal planes agrees with the trend of the major mapped faults offshore and its mechanism is consistent with the missing component of plate convergence not taken up by the onshore strike slip fault systems and the idea of a weak san andreas fault system the rupture process of the chalfant valley earthquake was yet more complicated the source time function indicates that in a 4 sec time window three asperities were broken the source mechanism indicates right lateral strike slip faulting with a small normal faulting component on a fault that dips approximately 50 southwest earthquake activity suggests that presently the deformation in the northern part of the owens valley which includes the chalfant valley is dominated by conjugate strike slip faults which strike obliquely to the main range bounding normal faults the waveforms indicate the presence of a low velocity zone at a depth of about 20 km in the crust in the chalfant valley a synthesis of information from waveform modeling first motion fault plane solutions and aftershock distributions indicates that the nucleation and or termination of rupture for the north palm springs and the chalfant valley events were controlled by preexisting fault geometry

development of a remotely controlled debris flow monitoring system in the dolomites acquabona italy direct measurements of the hydrological conditions for the occurrence of debris flows and of flow behaviour are of the outmost importance for developing effective flow prevention techniques an automated and remotely controlled monitoring system was installed in acquabona creek in the dolomites italian eastern alps where debris flows occur every year its present configuration consists of three on site stations located in the debris flow initiation area in the lower channel and in the retention basin the monitoring system is equipped with sensors for measuring rainfall pore water pressure in the mobile channel bottom ground vibrations debris flow depth total normal stress and fluid pore pressure at the base of the flow three video cameras take motion pictures of the events at the initiation zone in the lower channel and in the deposition area data from the on site stations are radio transmitted to an off site station and stored in a host pc from where they are telemetrically downloaded and used by the padova university for the study of debris flows the efficiency of the sensors and of the whole monitoring system has been verified by the analysis of data collected so far examples of these data are presented and briefly discussed if implemented at the numerous debris flow sites in the dolomitic region the technology used derived from the development of this system will provide civil defence and warn residents of impending debris flows copyright 2003 john wiley sons ltd

occurrence conditions of roll waves for three grain fluid models and comparison with results from experiments and field observation for the flow and deposition behaviour of debris flows phenomena like particle sorting levee formation and the development of roll waves are expected to be important processes however these processes are not well understood and hardly implemented in modelling approaches in this study we focus on the development of roll waves and derive advanced criteria separating stable and instable flow regimes for three debris flowmodels these criteria are expressed using critical froude numbers each of these simple flow models reflect different sources of flow resistance laminar viscous stress bingham type dispersive stress due to particle collision bagnold type and a model combining turbulent and dispersive stresses subsequently we compare the predictions from these models with results from laboratory experiments with grain fluid mixtures in a straight flume and with observations from a debris flow monitoring site at the lattenbach creek in austria the experimental flows match with a turbulent flow model including particle collisions for the natural flows the connection between models and observations is not clear due to limited field data the results of our study contribute to an improved determination of critical flow conditions and provide data for model testing

geohazard cascade and mechanism of large debris flows in tianmo gully se tibetan plateau and implications to hazard monitoring abstract alpine glaciers and permafrost are sensitive to climate change and their degradation due to annual temperature increasing has already induced many mass movements such as debris flows on september 4 of 2007 july 25 31 and september 5 8 of 2010 three large debris flows took place in tianmo gully a left bank tributary of parlung river southeast tibetan plateau the debris flows blocked the river and a section of highway 450 m long including a bridge 76 m long were destroyed by the subsequent outburst flood this paper based on post event investigations witness accounts news reports and satellite image interpretation systematically analyses the geo environments climate conditions and sources of these debris flow events their differences in flow process surge numbers and velocity suggest that they resulted from different geohazard processes cascades and initiation mechanisms the 2007 debris flow originated from a bare rock moraine collapse next to the cirque due to strong alternation of wet and dry conditions the mass moved down the gully with velocity of 30 40 m s estimated by back calculation using superelevation and run up it entrained moraine avalanched snow ice and water from the channel and transformed into high speed debris flow crossing the parlung river and finally depositing onto the highway the other two events in july and september of 2010 initiated from two channel bank landslides triggered by melt water and concentrated rainfall which dammed the channel the subsequent landslide dam failure generated debris flows over several days with velocities of 12 14 m s that temporally blocked parlung river the initiation mechanisms of most large debris flows recorded in parlung region are similar to the events in tianmo gully originating either from rock moraine avalanches or from the collapse of a landslide dam this implies that the periglacial degradation of bedrock and moraine is the key process to be monitored and assessed under climate warming the paper applies the geohazard mechanisms and cascade to hazard monitoring in order to protect the existing sichuan tibet highway and the forthcoming railway

correlation of carbon dioxide abundance with temperature in clastic hydrocarbon reservoirs relationship to inorganic chemical equilibrium the mol co2 of gas reservoired in sandstones tends to increase with increasing temperature along both the us gulf coast and the norwegian continental shelf each of these provinces displays identical linear correlations between temperature and the log of the partial pressure of co2 i e pco2 in the reservoir fluid that is the product of the mol co2 the reservoir pressure this correlation is the same both in gulf coast reservoirs younger than 17 ma and in norwegian reservoirs of jurassic to triassic age 144 245 ma indicating that it is not dependent on reaction kinetics norwegian shelf data indicate that the same correlation also applies for gas condensate and oil reservoirs we suggest that the log pco2versus temperature correlation is the result of inorganic chemical equilibria between feldspar clay and carbonate minerals a trend of decreasing ph with increasing temperature is fixed by equilibria between aluminosilicate minerals feldspar kaolinite at lower temperatures followed by various reactions between kaolinite illite chlorite and feldspar as temperatures exceed 110 140 c responding to the ph set by the aluminosilicate system co2 activity in the formation water and thereby co2 partial pressure in any gas phase present is controlled by equilibrium with carbonate minerals this model predicts that co2 released by organic maturation will in general result in precipitation of carbonate minerals below 100 120 c and that there should be widespread carbonate dissolution at higher temperatures

field observations of a debris flow event in the dolomites a debris flow event occurred in june 1997 in the dolomites eastern alps italy the phenomenon was directly observed in the field and recorded by a video camera near its initiation area the debris flow originated shortly after an intense rainstorm 25 mm in 30 min whose runoff mobilised the loose coarse debris that filled the bottom of the channel in its upper part the analysis of the steep headwater basin indicates a very short concentration time 9 14 min that fits the quick hydrological response observed in the field the debris flow mobilisation was not contemporaneous with the arrival of the peak water discharge in the initiation area probably due to the time required for the saturation of the highly conductive channel bed material channel cross section measurements taken along the flow channel indicate debris flow peak velocity and discharge ranging from 3 1 to 9 0 m s and from 23 to 71 m3 s respectively samples collected immediately after deposition were used to determine the water content and bulk density of the material channel scouring fines enrichment and transported volume increase testify erosion and entrainment of material along the flow channel field estimates of the rheological properties based on open channel flow of bingham fluid indicate a yield strength of 5000 400 pa and relatively low viscosity 60 326 pa s probably due to a high percentage of fines approx 30

field and laboratory analysis of the runout characteristics of hillslope debris flows in switzerland abstract hillslope debris flows are unconfined flows that originate by shallow failures in unconsolidated material at steep slopes in spite of their significant hazard for persons and infrastructure in mountainous regions research on hillslope debris flows is rather scarce in comparison to other landslide types this study focusses on the runout characteristics of hillslope debris flows applying two different approaches first detailed landslide inventories which include field measurements of 548 slope failures that occurred during the last two decades in seven parts of switzerland were analysed second laboratory tests were carried out to study the effect of the soil water content grain size distribution and mobilized volume on the runout behaviour of hillslope debris flows most of the failures in the field started as shallow translational slides at terrain slopes between 25 and 45 and involved volumes of some tens to a few hundred cubic meters an analysis of the runout distance of 117 hillslope debris flows showed that they normally travelled some tens of meters but sometimes the runout exceeded 300 m a positive relation between volume and runout distance and between volume and affected area was observed although there is considerable scatter in the data the affected area of 63 hillslope debris flows ranged from 100 to 1500 m2 based on the field data a 7 5 m long laboratory hillslope was designed with a geometrical scale factor of 20 a total of 75 runs with volumes from 4 to 20 dm3 water contents from 18 to 38 and four grain size distributions were carried out the laboratory tests revealed that water content is the dominant control but also the clay content strongly influences the runout distance and the affected area even a small increase in water or clay content produces a considerably larger or smaller runout distance respectively in contrast the influence of the volume on the runout was smaller and a positive relation was observed between these two parameters the field and laboratory results are in general agreement and consistent with the results of other studies the results of this work improve the understanding of hillslope debris flows and may aid in the hazard assessments of these processes

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

an empirical approach to studying debris flows implications for planetary modeling studies 1 high resolution images acquired by the mars global survey mars orbiter camera show gullies on the walls of impact craters and valley systems on mars depositional aprons associated with these gullies have been interpreted by malin and edgett 2000 to be characteristic of debris flow and to indicate the presence of sources of liquid water at shallow depths below the martian surface by focusing on a terrestrial debris flow we test the application of chezy type modeling to provide more direct estimates of the dynamics of proposed debris flows on mars traditionally planetary scientists constrained by available remotely sensed data have used a range of flow models to gain insights from deposits into the behavior and rheologic nature of features such as lava flows debris flows and gravity driven flows on the basis of these model results broad interpretations of the physics governing flows of granular materials have been tempting based on limited field derived data this study tests and validates the extent to which the absolute value and relative variations of empirical parameters derived from the chezy type models describe the behavior of the general s slide debris flow 38 24 n 78 23 w in madison county virginia the results indicate that extreme caution must be taken when interpreting model results for turbulent flows of granular materials we obtained high precision topographic profiles superelevation data sedimentary facies and sedimentary textural properties over the debris flow this study focuses on the empirical parameter c whose value gauges energy dissipation in a flow thereby called flow resistance using field observations both variations and absolute values of c along the debris flow have been computed using two approaches 1 assuming constant volumetric flow rate q where only topography and high resolution images are required to compute channel dimensions and 2 a variable q calculated using field derived data assuming near newtonian flow conditions in the debris flow estimated values of c range from 0 035 to 0 099 when q is fixed c decreases as a function of distance downstream when q varies and c is computed from field derived flow speeds its value tends to increase downstream slightly these opposite results have been compared to the field observations to determine which best describes the behavior of the flow the variations in c downstream obtained using the flow speeds are most consistent with the geomorphic evidence for erosion of material by the debris flow and the presence of bends in the channel the average values of c 0 036 0 33 for the general s slide have been compared with computed c values for newtonian and near newtonian flows to assess the rheology of the flow during emplacement our terrestrial study demonstrates that advances in understanding of the dynamics of debris flows on the mars depends on obtaining debris flow speeds in addition to channel topography and flow thickness rather than just on channel topography flow thickness and the assumption that q is constant mars orbiter camera moc and mars observer laser altimeter mola data can be used to derive channel topography flow thickness and possibly flow speeds such data will provide more direct estimates of the dynamics of debris flows on mars than are currently available

latest pleistocene and holocene slip rates on the lone mountain fault evidence for accelerating slip in the silver peak lone mountain extensional complex determining the constancy of fault slip rates over time is critical in characterizing strain distribution across plate boundaries such as the pacific north american plate boundary in the western u s we present results from the lone mountain fault a normal fault within the southern walker lane that suggest slip rates there may have increased approximately twofold since the late pleistocene we combine detailed field surficial mapping topographic surveying and 10be cosmogenic nuclide exposure ages to calculate new late pleistocene and holocene slip rates on the lone mountain fault alluvial fans with ages of 14 6 1 4 ka and 8 0 0 9 ka are vertically offset 10 2 0 6 m and 4 7 0 6 m respectively yielding vertical slip rates of 0 7 0 1 mm yr and 0 6 0 1 mm yr these slip rates are faster than the rates of 0 1 to 0 4 mm yr from earlier in the pleistocene defining a pattern of accelerating slip on the lone mountain fault over a timescale of 104 years the possibility of accelerating slip rates in parts of the walker lane partially reconciles the observed discrepancy between long and short term slip rates in this region and elucidates the distribution of strain across an evolving plate boundary

frequency and magnitude of debris flows on cheekye river british columbia abstract natural hazard and risk assessments are predicated on a detailed understanding of the relationship between frequency and magnitude of the hazardous process under investigation when information is sought from the deep past i e several thousand years continuous event records do not exist and the researcher has to rely on proxy data to develop the frequency magnitude f m model such work is often prohibitively expensive and few well researched examples for mass movement are available worldwide the cheekye fan is a desirable location for land development and has a depth and breadth of previous research unprecedented on any debris flow fan in canada we pursued two principal strains of research to formulate a reliable f m relationship the first focuses on stratigraphic analyses combined with radiometric dating and dendrochronology to reconstruct a comprehensive picture of holocene debris flow activity the second approach examines hydrological limitations of rock avalanche evolution into debris flows through either entrainment of saturated sediments or by failure of a landslide generated dam and upstream impoundment we thus hypothesize that debris flows from cheekye river can be separated into two quasi homogenous populations those that are typically triggered by relatively small debris avalanches slumps or rock falls or simply by progressive bulking of in stream erodible sediments and those that are thought to result from transformation of rock avalanches our work suggests that debris flows exceeding some 3 million m3 in volume are unlikely to reach the cheekye fan as a result of limited water available to fully fluidize a rock avalanche this analysis has also demonstrated that in order to arrive at reasonable estimates for the frequency and magnitude of debris flows on a complex alluvial fan significant multidisciplinary efforts are required without the significant precursor investigations and the additional efforts of this study life and property may be jeopardized or the design of debris flow mitigation may be subject to considerable and unquantifiable error

3d dem investigation on the morphology and structure of landslide dams formed by dry granular flows abstract large scale landslide dams triggered by earthquakes or rainfall can cause disasters due to inundation upstream and outburst floods downstream after dam failure landslide dams formed by rock debris avalanches are loose in structure and have a lack of stability thus they are more susceptible to breaking the morphological and structural features of landslide dams directly depend on the formation process and greatly affect the dam stability as well as the dam failure modes this study presents the transportation and deposition characteristics of dry granular flows with grains of mixed sizes during the formation of landslide dams via 3d discrete element method dem simulations mainly taking into consideration of the influence of the sliding area length angle and roughness the results show reverse segregation during grain transportation and deposition processes the position of the particles forming the initial deposited layers was also reversed it was found that when the sliding area angle was larger the crest surface frontal angle and deposit width increased with the increment of the sliding area length for lower sliding area angles the deposit width and crest surface frontal angle showed little change the increase of sliding length and base friction coefficient as well as the decrease of the sliding area angle will enhance the size segregation as the slope angle increases the dominant direction of the force chains shifts significantly and the sliding length mainly influences the magnitude of the normal contact force in the other directions these considerations can contribute to a better understanding of the landslide dam morphology and structure after their formation

a study of a flowslide with significant entrainment in loess areas in china flowslides are a frequent type of natural disaster in loess areas and may result in the significant loss of properties and or casualties the dagou flowslide is a typical event in a loess area and is accompanied by significant sediment entrainment to analyze the mechanisms responsible for flowslides and to obtain the parameters for a runout analysis a field investigation was conducted specimens were sampled on site to carry out laboratory tests including a triaxial test sieve analysis and chemical component analysis the parameters were used in the runout study employing an energy based runout model an analytical entrainment model was adopted to calculate the entrainment after considering physical properties and the mechanism of the entrainment process of the loess finally the entrainment model was incorporated into the runout model to simulate the post failure process of this case energy dissipation due to the deformation of slices was considered as it was thought to be important for a slide with a significant deformation the simulation results were compared with the measurements including runout distance total volume erosion depth deposition height at different sections and velocities at specific locations the results indicate that the energy based runout model together with the entrainment model can capture the kinematic characteristics of the dagou flowslide therefore it is feasible to use this model to predict the runout characteristics of flowslides in similar areas copyright c 2017 john wiley sons ltd

faulting on the volcanic tableland owens valley california the volcanic tableland brittle surface of the 764 000 yr old bishop tuff documents extensive faulting in the northern owens valley california during the late quaternary the tableland surface is cut by at least 226 fault scarps with a total of 328 km of surface rupture scarps are lens shaped rips in the surface of the bishop tuff with vertical offsets of a few meters to 140 m and lengths up to several kilometers the scarps have an average trend of n10 20 w and dip steeply both to the east and west the tableland records at least 290 m of cross valley extension in the last 764 000 yrs at an average rate of at least 400 m m y and a cumulative seismic moment of at least 2 8 cdot 10 28 dyne cm the volcanic tableland lies astride what has been called the white mountain seismic gap of the eastern california central nevada seismic zone seismic moment recorded on the tableland can be used to estimate average recurrence interval of surface rupturing earthquakes on the floor of the owens valley

a model for the runout analysis of rapid flow slides debris flows and avalanches runout analyses are used for risk assessment and design of remedial measures against rapid landslides such as debris flows debris avalanches rockslide avalanches large scale liquefaction failure

the maximum background earthquake for the basin and range province western north america the maximum background earthquake mbe is the largest earthquake not associated with significant primary surface rupture the mbe is estimated for the basin and range province considering 22 earthquakes from the province and a simple physical model of a circular rupture in the seismogenic zone in the basin and range province the number of historical earthquakes in the magnitude range 6 to 6 6 without significant surface rupture is clearly greater than the two events below magnitude 6 6 with primary surface rupture based on the historical record the mbe for the basin and range province is magnitude 6 6 but given the various uncertainties involved the usage of a magnitude value of 6 5 may be more reasonable for seismic hazard studied

evaluation of approaches to calculate debris flow parameters for hazard assessment abstract many different runout prediction methods can be applied to estimate the mobility of future debris flows during hazard assessment the present article reviews the empirical analytical simple flow routing and numerical techniques all these techniques were applied to back calculate a debris flow which occurred in 1982 at la guingueta catchment in the eastern pyrenees a sensitivity analysis of input parameters was carried out while special attention was paid to the influence of rheological parameters we used the voellmy fluid rheology for our analytical and numerical modelling since this flow resistance law coincided best with field observations the simulation results indicated that the basal friction coefficients rather affect the runout distance while the turbulence terms mainly influence flow velocity a comparison of the velocity computed on the fan showed that the analytical model calculated values similar to the numerical ones the values of our rheological parameters calibrated at la guingueta agree with data back calculated for other debris flows empirical relationships represent another method to estimate total runout distance the results confirmed that they contain an important uncertainty and they are strictly valid only for the conditions which were the basis for their development with regards to the simple flow routing algorithm this methods could satisfactorily simulate the total area affected by the 1982 debris flow but it was not able to directly calculate total runout distance and velocity finally a suggestion on how different runout prediction methods can be applied to generate debris flow hazard maps is presented taking into account the definition of hazard and intensity the best choice would be to divide the resulting hazard maps into two types final hazard maps and preliminary hazard maps only the use of numerical models provided final hazard maps because they could incorporate different event magnitudes and they supplied output values for intensity calculation in contrast empirical relationships and flow routing algorithms or a combination of both could be applied to create preliminary hazard maps the present study only focussed on runout prediction methods other necessary tasks to complete the hazard assessment can be looked up in the guidelines for landslide susceptibility hazard and risk zoning included in this special issue

cenozoic tectonic evolution of the white mountains california and nevada the white mountains represent the westernmost range of the central northern basin and range province they are situated to the east of the unextended sierra nevada and represent a crustal block that is bounded along its western flank by the high angle white mountains fault zone the fault zone accommodates up to 8 km of total dip slip displacement investigation of the structural and thermal history of the white mountains indicates a two stage cenozoic tectonic evolution preextensional miocene volcanic rocks preserved along the eastern side of the range unconformably overlie mesozoic granitic basement and currently dip up to 25 to the east recording the total cenozoic tilt of the crustal block apatite fission track and u th he thermochronological data indicate that the white mountains underwent rapid exhumation and eastward tilting in the middle miocene starting at ca 12 ma geologic mapping 1 10 000 fault kinematic analysis and dating of younger volcanic sequences show that following middle miocene east west extension the white mountains have been dominated by right lateral transtensional deformation related to the walker lane belt the eruption of late miocene and pliocene volcanic sequences in the eastern white mountains postdates the majority of the uplift of the range as evidenced by infilling of paleodrainages and the presence of east directed flow fabrics fault kinematic indicators from the white mountains fault zone are characterized by apparent overprinting of dip slip fault motion indicators by right lateral slickenfibers and fault striations demonstrating that the range bounding fault system along the western side of the white mountains was reactivated as a dextral strike slip fault system at the northern and southern ends of the range pliocene right lateral transtension along this northwest southeast trending fault systems resulted in the formation of northeast trending pull apart basins that truncate the mountain range and transfer strike slip displacement eastward from the owens valley fault zone to the fish lake valley fault zone the inception of strike slip faulting in fish lake valley occurred at ca 6 ma as constrained by late miocene volcanic units right lateral faulting on the western side of the white mountains occurred at ca 3 ma and is distinctly younger than the faulting in the fish lake valley area indicating a westward migration of transcurrent deformation through time

quantitative analysis of debris torrent hazards for design of remedial measures debris torrents which are rapid flows of soil and organic debris down steep mountain channels are a major natural hazard in many parts of british columbia a series of recent occurrences along the

superelevation of flowing avalanches around curved channel bends flowing avalanches are those with a dense core of flowing granular material at the base which dominates the dynamics causing friction sometimes when avalanches descend they encounter curved channel bends which cause the flowing material to superelevate or climb up on the wall of the channel bend so that the level of the flowing snow is higher on the outside of the bend than at the center of the channel this can provide important information about avalanche speeds the conventional approach for estimating speeds is mathematically equivalent to one developed from equations based on fluid mechanics with a balance between fluid pressure force and centrifugal force to yield a simple expression which relates channel radius avalanche speed and superelevation geometry in this paper the conventional theory is replaced by one which relates avalanche speed to basal friction as appropriate for flowing snow passive snow pressure accounting for friction between snow particles channel radius and superelevation geometry it is shown that the conventional theory is physically unrealistic for flowing snow modeled as a frictional material also the conventional theory will result in lower speed estimates than the new formulation for the same amount of superelevation

field and laboratory investigations of runout distances of debris flows in the dolomites eastern italian alps abstract the estimation of runout distances on fans has a major role in assessing debris flow hazards different methods have been devised for this purpose volume balance limiting topographic methods empirical equations and physical approaches data collected from field observations are the basis for developing testing and improving predictive methods while laboratory tests on small scale models are another suitable approach for studying debris flow runout under controlled conditions and for developing predictive equations this paper analyses the problem of assessing runout distance focusing on six debris flows that were triggered on july 5th 2006 by intense rainfall near cortina d ampezzo dolomites north eastern italy detailed field surveys were carried out immediately after the event in the triggering zone along the channels and in the deposition areas a fine scale digital terrain model of the study area was established by aerial lidar measurements total travel and runout distances on fans measured in the field were compared with the results of formulae from the literature empirical statistical and physically oriented and samples of sediment collected from deposition lobes were used for laboratory tests the experimental device employed in the tests consists of a tilting flume with an inclination from 0 to 38 on which a steel tank with a removable gate was installed at variable distances from the outlet a final horizontal plane works as the deposition area samples of different volumes and variable sediment concentrations were tested multiple regression analysis was used to assess the length of the deposits as a function of both the potential energy of the mass and the sediment concentration of the flow our comparison of the results of laboratory tests with field data suggests that an energy based runout formula might predict the runout distances of debris flows in the dolomites

surface slopes velocity profiles and fluid pressure in coarse grained debris flows saturated with water and mud data on the internal velocity distribution of flowing sediment fluid mixtures such as debris flows are rare but necessary for model development and testing a probe to measure the mean particle velocity at different depths and different locations within experimental debris flows in a 4 m diameter rotating drum was developed in addition the flow depth basal normal stress and basal pore fluid pressure were also measured results show that for a given sediment fluid mixture the velocity profiles collapse to distinct non dimensional profiles macroscopic flow behaviour shows great similarity with mean surface slopes weakly dependent on the shear rate for water saturated gravel but strongly shear rate dependent when pores are filled with mud poorly sorted material with a high content of fines produced fluid pressures close to normal stress and sidewall friction had a strong effect on the flow pattern our results reveal variability in profile characteristics for flows displaying similar macro dynamics and provide data for model testing

an integrated method for rapid estimation of the valley incision by debris flows abstract valley incision by debris flow is an important process in creating and maintaining the topography of a valley in addition to explaining the significant growth of the magnitudes of debris flow hazards in this paper we introduce a semi empirical method to quantitatively estimate the valley incision process by debris flows over complex bed surface we first reproduce natural bed surface across the valley by a polyline and use a hydrograph of discharge versus time to represent the temporal variation of debris flow process the presented method subsequently predicts the debris flow behavior over an irregular bed surface a dynamic erosion law considers the solved debris flow behavior and estimates an instantaneous erosion rate finally the accumulative incision depth of bed sediment is calculated reshaping the initial bed surface across the valley the presented method is simple and therefore notably beneficial for practical work the performance of the proposed method has been tested using two case study applications results demonstrate that the presented method estimates comparable incision depth as revealed in the in situ survey and the numerical simulation

depositional processes in large scale debris flow experiments this study examines the depositional process and characteristics of deposits of large scale experimental debris flows to 15 m3 composed of mixtures of gravel to 32 mm sand and mud the experiments were performed using a 95 m long 2 m wide debris flow flume that slopes 31 following release experimental debris flows invariably developed numerous shallow 10 cm deep surges sediment transported by surges accumulated abruptly on a 3 runout slope at the mouth of the flume deposits developed in a complex manner through a combination of shoving forward and shouldering aside previously deposited debris and through progressive vertical accretion progressive accretion by the experimental flows is contrary to commonly assumed en masse sedimentation by debris flows despite progressive sediment emplacement deposits were composed of unstratified accumulations of generally unsorted debris hence massively textured poorly sorted debris flow deposits are not emplaced uniquely en masse the depositional

velocity and runout simulation of destructive debris flows and debris avalanches in pyroclastic deposits campania region italy the campanian apennines are characterized by the presence of monocline ridges mainly formed by limestone during the periods of volcanic activity of the somma vesuvius and phlegrean fields the ridges were mantled with pyroclastic materials in varying thickness the pyroclastics have been involved in destructive landslides both in historical time and in the recent past 1997 1998 1999 the landslides occur following intense and prolonged rainfalls in some cases landslides extended up to 4 km into the surrounding lowlands and reached towns causing severe destruction and over 200 deaths generally the landslides begin as small debris slides that develop into large shallow debris avalanches or debris flows involving pyroclastic horizons and colluvial soils 0 5 2 m thick on steep and vegetated slopes often at the heads of gullies during motion the landslide materials eroded vegetation and soils from the slope so that the moving material volume tended to increase then proceeding towards and beyond the base of the slopes the phenomena evolved into hyperconcentrated streamflow due to dilution by incorporating water the results of motion analyses are described an empirical rheological relationship was used including two principal terms that depend on the total normal stress and on the flow velocity on this basis the model has simulated the velocity and duration of debris avalanches and the distribution of the deposits the selected areas were those of sarno quindici and cervinara where a large amount of data is available both on the material properties and geomorphological setting it was found that the majority of the cases at the two sites can be simulated successfully with only one specific pair of rheologic parameters this provides the possibility for first order predictions to be made of the motion of future landslides such predictions will be a valuable tool for outlining potential hazard areas and designing remedial measures

carboxylic acid anions in formation waters san joaquin basin and louisiana gulf coast u s a implications for clastic diagenesis critical comment the analyses of carboxylic acid anions caas in san joaquin basin and louisiana gulf coast formation waters published by macgowan and scrdam 1990 do little to resolve the important question of whether caas are of great significance to clastic diagenesis over the temperature range in which they dominate fluid alkalinity as advocated by these two authors comparison of their analyses with analyses of formation waters from the same wells previously published by three independent research groups hanor and workman 1986 land et al 1988 and land and macpherson 1989 and fisher and boles 1990 a body of data not discussed in their article reveals that most of the macgowan and surdam values are grossly inflated relative to the previous analyses table 1 fig 1 cedures of llco et al 1982 while field procedures for caas now normally include the addition of a bactericide to the sample an independent check on the upper limit of total caas which could have been present in this water is provided by the results of an alkalinity titration to ph 2 5 also published by hanor and workman 1986 which show that the total concentration of weak acid anions bicarbonate plus caas could not have exceeded approximately 428 mg 1 the alkalinity determinations were done shortly after collection on separate untreated aliquots stored in gas tight glass containers further details are given in workman 1985

recent state of stress change in the walker lane zone western basin and range province united states the nw to north trending walker lane zone wlz is located along the western boundary of the northern basin and range province with the sierra nevada this zone is distinguished from the surrounding basin and range province on the basis of irregular topography and evidence for both normal and strike slip holocene faulting inversion of slip vectors from active faults historic fault offsets and earthquake focal mechanisms indicate two distinct quaternary stress regimes within the wlz both of which are characterized by a consistent wnw 3 axis these are a normal faulting regime with a mean 3 axis of n85 9 w and a mean stress ratio r value r 2 1 3 1 of 0 63 0 74 and a younger strike slip faulting regime with a similar mean 3 axis n65 70 w and r values ranging between 0 1 and 0 2 this younger regime is compatible with historic fault offsets and earthquake focal mechanisms both the extensional and strike slip stress regimes reactivated inherited mesozoic and cenozoic structures and also produced new faults the present day strike slip stress regime has produced strike slip normal oblique slip and normal dip slip historic faulting previous workers have explained the complex interaction of active strike slip oblique and normal faulting in the wlz as a simple consequence of a single stress state with a consistent wnw 3 axis and transitional between strike slip and normal faulting maximum horizontal stress approximately equal to vertical stress or r 0 in both regimes with minor local fluctuations the slip data reported here support previous results from owens valley that suggest deformation within temporally distinct normal and strike slip faulting stress regimes with a roughly constant wnw trending 3 axis zoback 1989 a recent change from a normal faulting to a strike slip faulting stress regime is indicated by the crosscutting striae on faults in basalts 300 000 years old and is consistent with the dominantly strike slip earthquake focal mechanisms and the youngest striae observed on faults in plio quaternary deposits geologic control on the timing of the change is poor it is impossible to determine if there has been a single recent absolute change or if there is rather an alternating or cyclical variation in stress magnitudes our slip data in particular the cross cutting normal and strike slip striae on the same fault plane are inconsistent with postulated simple strain partitioning of deformation within a single regional stress field suggested for the wlz by wesnousky and jones 1994 the location of the wlz between the deep seated regional extension of the basin and range and the right lateral strike slip regional tectonics of the san andreas fault zone is probably responsible for the complex interaction of tectonic regimes in this transition zone in early to mid tertiary time the wlz appears to have had a similarly complex deformational history in this case as a back arc or intra arc region accommodating at least part of the right lateral component of oblique convergence as well as a component of extension

debris flow velocities and superelevation in a curved laboratory channel the vortex equation is often used to estimate the front velocity of debris flows using the lateral slope of the flow surface through a channel bend of a given radius here we report on laboratory e