levee morphology and sedimentology along the lower tuross river south eastern australia levees on the lower tuross river in south eastern australia reflect a complex interplay between depositional and erosional processes stream power conditioned primarily by valley width is the key determinant of levee morphology and sedimentology in this confined valley setting three styles of levee are described the rewlee levee is functionally linked to a flood channel in narrow valley settings 250 m these levees contain a diverse facies assemblage characterized by various scales of erosion surfaces vertical accretion on levees has produced conditions under which stream power values exceed the threshold for catastrophic floodplain stripping the levee at the mortfield site is associated with less confined settings valley width 500 600 m which present lower flood stage and stream power conditions this levee hosts a wide range of facies but erosion surfaces are seldom observed in the more open valley setting at the central site valley width 700 1000 m levees comprise uniform fine grained deposits which grade to pronounced distal floodplains with backswamps as levees reflect a combination of within channel and overbank processes both depositional and erosional these geomorphic features influence the character and sedimentology of adjacent landforms and the associated alluvial architecture of the basin

form facies and depositional history of the north long john rock avalanche owens valley california the prehistoric but geomorphically pristine north long john rock avalanche of the inyo mountains piedmont california formed by the catastrophic collapse and disintegration of a 500 1000 m range front bedrock slab this failure rapidly produced and transferred 25 million cubic metres of new sediment to the piedmont where it was deposited in a trough between two coalesced alluvial fans the avalanche consists of nearly monolithologic aplitic unstratified very angular muddy cobble pebble gravel with boulders concentrated at the top and outer margins the deposits are clast supported except in the lower central zone coarse clasts exhibit crackle breccia fabric and the voluminous equant pebbles are the disaggregated products of these clasts the avalanche deposits are distributed in a u shaped body with paired lateral levees 10 60 m high that extend 1560 m from the range front to a 108 m high distal snout each levee contains three segments that along with the snout overlap and extend progress

worldwide initiation of holocene marine deltas by deceleration of sea level rise radiocarbon dated deltaic sequences of holocene age from different parts of the world began to accumulate within a restricted time range from about 8500 to 6500 years ago evaluation of major delta processes indicates that deceleration in sea level rise was the key factor in holocene delta formation within many deltas there is as much as a 2000 year age range between basal deposits in seaward and landward cores this age difference records the progressive landward migration of near mean sea level depositional environments during the lower to mid holocene establishment of a chronostratigraphic framework for holocene delta development provides a fundamental global baseline for distinguishing sea level change from vertical land motion by tectonism and isostasy and for evaluating rates of future marine incursion into low lying deltas

river stabilisation due to changing climate and vegetation during the late quaternary in western tasmania australia abstract the stanley river in western tasmania australia contains sub fossil rainforest logs within the channel and floodplain of the more than 85 radiocarbon dates obtained all but 3 date from 17 ka to the present and permit an interpretation of fluvial and related environmental changes over this period particular attention is focused on the interactive relationship between the river and its riparian rainforest following the last glacial maximum the stanley river was a laterally active gravel load system reworking most of its valley floor in the upstream reaches with ameliorating conditions at the end of the pleistocene climate became less seasonal and flow regimes less energetic huon pines already present in the catchment re asserted themselves in the form of dense tree cover along the river banks and floodplains with basal floodplain deposition shifting from gravels to coarse sands and granules by about 3 5 ka a further change in climate reduced stream discharges substantially as a result the channel reduced in size transported finer sediment became laterally stable and the floodplain accreted with overbank deposits of sand and silt huon pines falling into the channel formed obstructions of woody debris some surviving for 2 ka these have reduced stream power and boundary shear stress further contributing to channel stability generational sequences of huon pines on the river banks some extending back 1 2 ka are additional evidence of this stability since the pleistocene changing climate and the re establishment of dense riparian rainforest appear to have stabilised the river channels and floodplains of western tasmania

landslide hazard assessment in the three gorges area of the yangtze river using aster imagery zigui badong this paper reports a regional assessment of landslide hazard in the three gorges area china based on terra 1 satellite advanced spaceborne thermal emission radiometer aster imagery data including a stereo image derived digital elevation model dem and multi spectral reflective and thermal imagery in combination with limited field investigation the three gorges dam and reservoir project has gained international attention not only for its great potential for hydro electrical power generation and flood control but also for its potentially harmful effects on the environment and socio economy the most significant and widespread natural hazard in the region is slope instability a simple multi variable elimination and characterisation model employing geometric mean and boolean decision rules has been applied to a multi criterion image dataset to categorise the area into a series of potential landslide hazard levels which are presented in map form the results presented here show high levels of hazard in and around all the main inhabited areas along the river limited fieldwork has been conducted to provide reliable ground control and the results of this paper show good correlation with this field evidence

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

large landslides associated with a diapiric fold in canelles reservoir spanish pyrenees detailed geological geomorphological mapping trenching and electrical resistivity imaging abstract detailed geomorphological geological mapping in canelles reservoir the spanish pyrenees reveals the presence of several large landslides overlooked in previous cartographic works one of the slope movements designated as the canelles landslide corresponds to a 40 10 6 m 3 translational landslide reactivated in 2006 by a severe decline in the reservoir water level the geomorphic features mapped in the upper part of the canelles landslide including surface ruptures corroborated by electrical resistivity imaging and trenching indicate multiple displacement episodes previous to the 2006 human induced event consistently the stratigraphic and structural relationships observed in a trench record at least two displacement events older and larger in magnitude than the 2006 reactivation the oldest recorded event occurred in the 6th to 7th centuries and the second in 1262 1679 yr ad this latter episode might be correlative to the 1373 ribagorza earthquake m w 6 2 which caused the reactivation of a landslide and the consequent destruction of a village in the adjacent valley the available data indicate that over more than one millennium the kinematics of the landslide has been characterised by discrete small displacement episodes these data together with the available literature on rapid rockslides do not concur with the acceleration predicted by modelling in a previous investigation which foresees a speed of 16 m s 1 despite the low average dip of the sliding surface 9 10 this case study illustrates that the trenching technique may provide valuable practical information on the past behaviour of landslides covering a much broader time span than instrumental and historical records

electrical imaging of sliding geometry and fluids associated with a deep seated landslide la clapiere france this paper deals with the applicability of electrical resistivity tomography ert for the recognition of large landslide structures at depths which have never previously been imaged accurately one of the most studied and instrumented deep landslides in europe is taken as an example the la clapiere landslide the first stage of the study consisted of an accurate geological mapping taking into account a morphological analysis of gravitational deformations this allowed a very fine definition of the landslide structure that could be compared with three provided ert profiles performed within the landslide body very good correlations were obtained for the determination of sub horizontal structures and associated fluid circulations it confirmed the position of the sliding surface that reached a maximum depth of 100 m forward computing was however necessary to determine the influence and then the presence of vertical discontinuities it supports the use of ert as an efficient tool for large scale landslide imaging such as deep seated landslides copyright 2010 john wiley sons ltd

a numerical comparison of 2d resistivity imaging with 10 electrode arrays numerical simulations are used to compare the resolution and efficiency of 2d resistivity imaging surveys for 10 electrode arrays the arrays analysed include polepole pp pole dipole pd half wenner hw wenner wn schlumberger sc dipole dipole dd wenner wb array gm multiple or moving gradient array gd and midpoint potential referred measurement mpr arrays five synthetic geological models simulating a buried channel a narrow conductive dike a narrow resistive dike dipping blocks and covered waste ponds were used to examine the surveying efficiency anomaly effects signal to noise ratios and the imaging capabilities of these arrays the responses to variations in the data density and noise sensitivities of these electrode configurations were also investigated using robust l1 norm inversion and smoothness constrained least squares l2 norm inversion for the five synthetic models the results show the following i gm and wn are less contaminated by noise than the other electrode arrays ii the relative anomaly effects for the different arrays vary with the geological models however the relatively high anomaly effects of pp gm and wb surveys do not always give a high resolution image pd dd and gd can yield better resolution images than gm pp wn and wb although they are more susceptible to noise contamination sc is also a strong candidate but is expected to give more edge effects iii the imaging quality of these arrays is relatively robust with respect to reductions in the data density of a multi electrode layout within the tested ranges iv the robust inversion generally gives better imaging results than the l2 norm inversion especially with noisy data except for the dipping block structure presented here v gd and mpr are well suited to multichannel surveying and gd may produce images that are comparable to those obtained with dd and pd accordingly the gd pd dd and sc arrays are strongly recommended for 2d resistivity imaging where the final choice will be determined by the expected geology the purpose of the survey and logistical considerations

determining the impact of the holocene highstand at the coastal fluvial interface shoalhaven river south eastern australia with enhanced rates of sea level rise predicted for the next century the upstream extent of sea level influence across coastal plains is a topic of public importance australian coastal rivers provide a testing ground for exploring this issue because the area is tectonically stable was not glaciated and experienced a holocene highstand between 7 4 and 2 ka of up to 1 5 m above australian height datum ahd in the shoalhaven river of new south wales investigation of a confined bedrock reach at wogamia 32 km inland has identified a unit of dark cohesive silt and sand with marine diatoms shell fragments and enhanced pyrite content interpreted as estuarine the unit is up to 13 m thick thickens downstream and is overlain by fluvial channel and floodplain deposits the estuarine unit on laps a remnant pleistocene terrace and extends to approximately 2 2 m ahd optically stimulated luminescence osl and radiocarbon ages suggest that estuarine deposition commenced prior to 7 8 ka cal bp predating the highstand by 500 years and that marine influence in the area continued to 5 3 0 7 ka during this period a delta probably persisted at wogamia where a narrow upstream reach opens out and subsequently advanced to fill the broad shoalhaven coastal embayment although the effect of sea level rise depends on many factors the results suggest that during a highstand at or above present sea level a strong marine influence may extend for tens of kilometres inland and penetrate confined bedrock reaches landward of coastal embayments copyright 2013 john wiley sons ltd

late pleistocene and holocene sea level change along the australian coast abstract tectonically the australian continent is relatively stable and as such it provides a good platform for studying late pleistocene and holocene sea level change the observations indicate that present sea level was reached at about 6000 years ago and that since then level has remained constant to within a few metres considerable spatial variability in the amplitude of the emergence and in the time at which sea levels first reached their present values have been observed spatial variability has also been observed in the sea level during the last glacial maximum and during the late phase of the holocene transgression much of this variaiblity is the result of the earth s adjustment to the glacial melting in the late pleistocene early holocene time and the concomitant distribution of this meltwater into the oceans conclusions that are drawn from matching observations with this glacio hydro isostatic model include the following 1 the mantle viscosity increases with depth the average upper mantle viscosity is about 2 3 10 20 pa s and the average lower mantle defined as below 670 km depth viscosity is about 10 22 pa s the average lithospheric thickness for the coastal and offshore region is about 70 80 km lateral variations in these mantle parameters are indicated 2 the addition of melwater into the oceans did not cease 6000 years ago but continued at a reduced rate up to more recent times adding an amount of water equivalent to a 3 m sea level rise in this interval 3 the amplitude of the holocene emergence is a function inter alia of coastal geometry and significant variations occur over distances of a few hundred kilometres and more holocene highstands of 1 2 m are generally well developed at the continental margins but are less well developed or do not developed at all at offshore islands and reefs 4 variations in the time of maximum emergence also occur being earlier at upstream tidal river sites than at coastal sites at offshore reefs or islands the sea level curve lags the coastal curves by 1000 years or more 5 considerable spatial variability occurs in the sea levels at the time of the last glacial maximum with variations of up to 30 m occurring across the continental shelves 6 there is generally no need to invoke tectonic movements to explain the sea level data along the australian coast but possible exceptions occur for the perth region and for tasmania

a large rockslide debris avalanche in cohesive soil at pink mountain northeastern british columbia canada abstract in early july 2002 a large rockslide debris avalanche occurred on the west slope of the pink mountain anticline in northeastern british columbia 57 04 n 122 52 w the slopes have been subjected to previous deformation and landsliding pre and post slide digital elevation models dems were created from aerial photography approximately 1 04 m m 3 of sandstone and shale travelled nearly 2 km from an elevation of 1460 m to 1010 m the landslide has a fahrboschung of 11 6 and covered 43 ha the rock debris entrained a certain amount of fine textured till and colluvium increasing its volume by 15 this entrainment caused partial liquefaction of the underlying soil thereby enhancing the mobility of the landslide we used a bingham rheological model to dynamically model the landslide with excellent correspondence between the analysis of the actual observed behaviour of the landslide

late holocene episodic displacement on fault scarps related to interstratal dissolution of evaporites teruel neogene graben ne spain abstract the mio pliocene formations of the turolian type section teruel graben spain have sagged due to dissolution of the underlying triassic evaporites generating a 1 7 km long monocline and accompanying synform with 130 m of structural relief the crest of the monocline is affected by a graben that counterbalances the shortening caused by passive bending in the adjacent syncline this graben is controlled by a master synthetic fault and a swarm of antithetic and synthetic faults with a conspicuous geomorphic expression after acquiring ground penetrating radar gpr profiles three trenches were excavated in depressions associated with uphill facing fault scarps to our knowledge these are the first trenches excavated across faults caused by deep seated dissolution of evaporites the geometrical relationships observed in two trenches indicate late holocene episodic displacement as many as 3 events some of the parameters estimated for the investigated faults are clearly different from those expectable for tectonic faults in this intraplate area they include high apparent vertical slip rates 0 6 1 mm yr low average recurrence of faulting events 1 2 2 ka and very high displacement per event values 65 cm for surface ruptures less then 200 m long our findings suggest that considering evaporite collapse faults as creeping structures is not a reliable criterion to differentiate between tectonic faults seismogenic and dissolution induced gravitational faults nonseismogenic

the effect of crustal structure on strong ground motion attenuation relations in eastern north america strong ground motion attenuation relations are usually described by smoothly decreasing functions of distance however consideration of wave propagation in the crust suggests that attenuation relations should be more complex such complexity may be present in strong ground motion data for eastern north american earthquakes which show amplitudes in the distance range of 60 to 150 km that lie above the trends at smaller and greater distances using a wavenumber integration method to compute green s functions and close in recordings of several earthquakes as empirical source functions we have generated synthetic seismograms that are in good agreement with regional and strong motion recordings of eastern north american earthquakes from these synthetic seismograms we have shown that the observed interval of relatively high amplitudes may be attributable to postcritically reflected s waves from the moho the presence and location of the interval of relatively high amplitudes is highly dependent on the crustal velocity structure and may therefore be expected to show regional variation however for any realistic structure model there will be a transition in the attenuation relation from an interval at shorter distances less than about 100 km that is dominated by direct waves to an interval at greater distances that is dominated by postcritically reflected waves the synthetic seismograms have response spectral velocities that match those of the recorded data and their m blg values are in good agreement with observed values

development of crestal normal faults associated with deepwater fold growth deepwater anticlines during their early stages of development approximately between interlimb angles of 180 and 140 grow and accumulate weak fine grained and poorly lithified sediment on their crests growth of the anticlines induced gravitational instability within the syn kinematic sediments and development of a range of shallow gravity driven failure mechanisms in addition to shallow tens of metres depth to detachment rotational landslides deeper seated normal fault swarms also affect the fold crests and upper fold limbs these faults tend to penetrate to depths between 200 and 800 m are 100s of metres to a few kilometres long planar to weakly curved in cross section and display throws in the order of tens of metres the faults do not sole out into a detachment but die out downwards they can occur as single sets or tiers of faults that have developed at different times in map view the fault patterns range from straight to anastamosing to highly curved with complex cross cutting relationships the number and orientation of faults corresponds to the maximum slope dip and direction and consequently the faults are inferred to be mainly the product of gravity induced deformation although tangential stresses arising from outer arc bending of a fold or crestal collapse in response to a mobile sedimentary unit may contribute to some extent

intensity prediction equations for north america abstract equations that predict intensity as a function of magnitude and distance are useful tools for hazard and risk assessment and in interpretation of both contemporary and historical earthquake information the intensity prediction equations of atkinson and wald 2007 hereafter aw07 have been remarkably successful in describing the level and intensity of motions reported under the did you feel it dyfi program over the last several years examination of the performance of aw07 for north american earthquakes evaluated using an extensive compiled database of dyfi observations from 2000 to 2013 suggests that there is little statistical basis for revising these equations however a problem with the aw07 equations is that they predict unrealistically large median intensities for large events m 6 at close distances in this study we revise aw07 to improve the intensity scaling at large magnitudes and close distances by reconciling intensity equations with ground motion prediction equations

holocene palaeoecology and formation of the shoalhaven river deltaic estuarine plains southeast australia the shoalhaven river is one of the largest rivers on the south coast of new south wales and the deltaic estuarine plains associated with its mouth represent a mature stage of infill of a barrier estuary the stratigraphy of sediments from more than 60 drillholes from the plains indicates that the area has infilled during the mid holocene as a result of input of marine sands associated with a sand barrier on the high energy coast and fluvial mud and sands from the shoalhaven river molluscan assemblages indicate that marine influence was initially widespread throughout the eastern and southern parts of the embayment and that most of the plains infilled under estuarine conditions prominent levees across the plains surface are interpreted to be part of a birdsfoot delta distributary complex and individual floodbasins accreted progressively as they were encapsulated by distributary extension these former tidal environments mean that there are extensive potential acid sulphate soil conditions beneath the

topographically associated but chronologically disjunct late quaternary floodplains and terraces in a partly confined valley south eastern australia the bellinger river catchment in the new england fold belt on the mid north coast of new south wales is characterized by an assemblage of stepped late quaternary alluvial units late pleistocene terraces were formed by large more competent rivers that eroded almost entire valley floors however a decline in discharge prior to the holocene has resulted in the abandonment of these deposits as elevated terraces or residual alluvium onlapped by contemporary floodplains intrinsic controls on floodplain formation appear to be superimposed over an early mid holocene climatic signature a fluvially active period known as the nambucca phase from 10 to 4 5 ka eroded late pleistocene terraces two floodplain surfaces one higher than the other both started to accrete vertically from 4 ka but with some valley locations remaining vulnerable to episodes of erosion resulting in substantial units of even younger basal alluvium the high floodplain is dominated by horizontally laminated vertically accreted sequences while the low floodplain which overlaps in age is characterized by pronounced cut and fill stratigraphy terraces and floodplains in partly confined settings can have similar elevations but be polycyclic with very different basal ages in such landscapes the classical assumption that individual terrace or floodplain profiles along a valley represent periods of coeval formation is shown to be frequently invalid copyright 2007 john wiley sons ltd

episodes of vertical accretion and catastrophic stripping a model of disequilibrium flood plain development this paper describes flood plains formed episodically by vertical accretion along high energy laterally stable channels in southeastern australia overbank deposition gradually builds a flood plain of fine textured alluvium over a period of hundreds or thousands of years following which catastrophic erosion by a single large flood or a series of more moderate floods strips the flood plain to a basal lag deposit from which it slowly reforms this periodic destruction appears due to the progressive development of large levee banks and flood plain surfaces of highly variable relief as the levees and flood plain grow overbank flow is gradually displaced from the broad flood plain into the main channel and flood plain backchannels with a resulting concentration of erosional energy eventually high flows greatly exceed erosional thresholds and wholesale scour of the channel boundary and flood plain occurs vertical accretion flood plains at different stages of development result in a wide range of bankfull recurrence intervals even along the same river some of these flood plains are so infrequently flooded that they can be mistaken for terraces formed under a prior flow regime the almost random but catastrophic nature of this flood plain erosion means that sediment supply and transport are highly variable and probably impossible to predict this model of flood plain formation is seen as only part of a continuum of alluvial environments ranging from vestigial coarsegrained traction load flood plains along high energy rivers in narrow gorges to extensive low gradient flood plains in which alluvial stratigraphy is dominated by fine grained overbank deposition

sedimentary facies and holocene progradation rates of the changjiang yangtze delta china abstract the changjiang yangtze river one of the largest rivers in the world has formed a broad tide dominated delta at its mouth during the holocene sea level highstand three boreholes cm97 js98 and hq98 were obtained from the changjiang delta plain in 1997 1998 to clarify the characteristics of tide dominated delta sediments and architecture based on sediment composition and texture and faunal content core sediments were divided into six depositional units in ascending order they were interpreted as tidal sand ridge prodelta delta front subtidal to lower intertidal flat upper intertidal flat and surface soil deposits the deltaic sequence from the prodelta deposits to the delta front deposits showed an upward coarsening succession overlain by an upward fining succession from the uppermost part of the delta front deposits to the surface soil thinly interlaminated to thinly interbedded sand and mud sand mud couplets and bidirectional cross laminations in these deposits show that tide is the key factor affecting the formation of changjiang deltaic facies sediment facies and their succession combined with ams 14c dating revealed that isochron lines cross unit boundaries clearly and delta progradation has occurred since about 6000 to 7000 years bp when the rising sea level neared or reached its present position the average progradation rate of the delta front was approximately 50 km kyear over the last 5000 years the progradation rate however increased abruptly ca 2000 years bp going from 38 to 80 km kyear the possible causes for this active progradation could have been an increase in sediment production in the drainage basin due to widespread human interference and or decrease in deposition in the middle reaches related to the channel stability caused by human activity and climatic cooling after the mid holocene

criteria for rapid sliding ii thermo hydro mechanical and scale effects in vaiont case abstract thermally induced excess pore pressures have been included into a two wedge evolutive model of vaiont landslide the problem requires the solution of a system of four coupled balance equations for the shear bands and the surrounding rock as well as the joint equation of motion of the entire slide the model predicts the high velocities observed and is consistent with other data slide geometry residual strength and conditions on the sliding surface the interpretation of a sensitivity analysis suggests that there exists a threshold permeability band in the range 10 8 to 10 10 m s which separates potentially fast motions from slow motions this conclusion is maintained if the scale of the landslide is reduced

geology and tsunamigenic potential of submarine landslides in santa barbara channel southern california abstract a large submarine landslide complex and four small landslides developed under the santa barbara channel suggesting a potential hazard from landslide generated tsunamis we integrate offshore stratigraphy and geologic structure multibeam bathymetric information and several kinds of seismic reflection data to understand how and when the submarine landslides formed seismic reflection data show that mass failure along the slope began at least 200 ka ago landslides appear as zones of poor reflectivity having an irregular upper surface and these zones alternate vertically with strong parallel reflections the emplacement ages of two of the three main landslide lobes are well established at 8 and 10 ka the source material for the youngest part of the landslide complex was sediment of probable late pleistocene and holocene age that accumulated in a shelf edge delta directly under this delta growth of faults and anticlines was particularly intense and tended to oversteepen the deltaic deposits these active structures also formed migration pathways and reservoirs for aqueous and hydrocarbon fluids from the deep basin tsunami deposits have been described from a low lying area near santa barbara and numerical modeling of tsunamis generated by hypothetical landslides in santa barbara channel indicates a moderate to severe threat borrero j c dolan j f and synolakis c e 2001 tsunamis within the eastern santa barbara channel geophys res lett 28 4 643 646 involving wave runups of 2 20 m for a range of assumed landslide volumes inundation from these waves however is expected to be highly focused so that only narrow 10 km sections of the shoreline would be affected

floodplains permafrost cottonwood trees and peat what happened the last time climate warmed suddenly in arctic alaska abstract we use the stratigraphy of floodplains on alaska s north slope to describe how tundra watersheds responded to climate changes over the last 15 000 calibrated years bp 15 cal ka bp two episodes of extremely rapid floodplain alluviation occurred during the pleistocene holocene transition one between 14 and 12 8 cal ka bp and the other between 11 5 and 9 5 cal ka bp these aggradation episodes coincided with periods of warming in summer when cottonwood populus balsamifera l expanded its range peatlands became established and widespread thermokarst occurred the two aggradation episodes were separated by a period of floodplain incision during the younger dryas under cooler and possibly drier conditions at times of increasing summer warmth melting permafrost and enhanced precipitation probably triggered widespread mass wasting on hillslopes that overwhelmed the capacity of streams to transport sediment downstream and rapid floodplain aggradation resulted after peatlands became widespread in the early holocene rivers slowly incised their valley fills because major pulses of sediment input were limited to times of rapid thaw and increasing moisture many floodplains on the north slope have been effectively decoupled from upstream hillslopes for much of the past 15 000 years our findings a confirm the sensitivity of arctic watersheds to rapid warming in summer b emphasize the importance of hillslope mass wasting in landscape scale responses to climate change and c suggest that the presence of peatland on this arctic landscape today has raised its geomorphic response threshold to climate warming compared to what it was 14 000 years ago

dating aboriginal stone walled fishtraps at lake condah southeast australia abstract direct dating of stone walled fishtraps has been a methodological challenge in archaeology and is generally considered insurmountable dating is usually associative linking traps to local archaeological sites and geomorphological features of known age limited excavation of sediments burying the lower sections of stone walled fishtrap features has been previously undertaken with limited success recent fine grained excavation and comprehensive ams dating and analysis of channel in fill sediments associated with an elaborate freshwater fishtrap complex at lake condah western victoria yields reliable insights into the phased construction and use of the feature an early phase of basalt bedrock removal to create a bifurcated channel was subsequently in filled with flood sediments incorporating stone artefacts and charcoal dated to c 6600 cal bp after a hiatus basalt blocks were added to the sides of the channel to create multi tiered walls within the past 600 800 years this site provides the first direct insights into the antiquity of the elaborate fishtrapping and aquaculture system developed by aboriginal people in the lake condah region and may represent one of the world s oldest known fishtraps

a late holocene deep seated landslide in the northern french pyrenees abstract a very large deep seated landslide dsl in the northern pyrenees with over 1 4 10 9 m 3 was mapped and dated based on sedimentation rates and 10 be terrestrial cosmogenic radionuclide surface exposure cre dating our analysis on the landslide reveals the role of inherited structures in the landslide process and highlighted typical gravitational morpho structures and a small lake trapped at the toe of the landslide head scarp the rate of lake sedimentation 0 86 0 57 mm yr 1 also provided us with the approximate age of the landslide 1106 540 yr the cre dating result highlights two main slope destabilization phases then we discussed the history of dsl activity and its controlling factors information related to historic markers and the absence of particular climate markers and changes during the medieval dark ages point to a single event in ad 1380 due to a major seismic event lavedan earthquake

optical dating of holocene sediments from a variety of geomorphic settings using single grains of quartz this paper presents an improved method for the optical dating of holocene sediments from a variety of geomorphic settings we have measured the equivalent dose de in individual grains of quartz using green laser light for optical stimulation and have simulated the de distributions for multiple grain synthetic aliquots using the single grain data for 12 samples of known independent age we show that application of a minimum age model to the single grain and small 10 grain aliquot de data provides the most accurate estimate of the burial dose for nine of the samples examined 3 aeolian 5 fluvial and 1 marine the weighted mean de as obtained using the central age model gives rise to burial age overestimates of up to a factor of 10 for these nine samples whether single grains small aliquots or large 100 grain aliquots are used for the other three samples two aeolian and one fluvial application of either the minimum age model or the central age model to the single grain small aliquot and large aliquot de data yields burial ages in accord with the independent age control we infer that these three samples were well bleached at the time of deposition these results show that heterogeneous bleaching of the optical dating signal is commonplace in nature and that aeolian transport offers no guarantee that the sample will be well bleached at the time of deposition we also show that grains sensitive to infrared ir stimulation can give rise to low de values which will result in significant underestimation of the burial dose and hence of the age of deposition we demonstrate that use of a modified single aliquot regenerative dose protocol incorporating ir stimulation prior to green light stimulation deals effectively with contamination by ir sensitive grains we conclude that application of the modified protocol to single grains or small aliquots of quartz using the lowest de population to estimate the burial dose is the best means of obtaining reliable ages for holocene sediments from a wide range of depositional environments d 2003 elsevier b v all rights reserved

spatial variability in the timing nature and extent of channel response to typical human disturbance along the upper hunter river new south wales australia prior to european settlement the upper hunter river near muswellbrook new south wales was a passively meandering gravel bed river of moderate sinuosity and relatively uniform channel width analyses of floodplain sedimentology archival records parish maps and aerial photographs document marked spatial variability in the pattern of channel change since european settlement in the 1820s different types rates and extents of change are reported for seven zones of adjustment along an 8 km study reach this variable adjustment reflects imposed antecedent controls buried terrace material and bedrock which have significantly influenced local variability in river sensitivity to change as well as contemporary morphodynamics and geomorphic complexity local variability in system responses to disturbance has important implications for future river management and rehabilitation

ground motions for induced earthquakes in oklahoma we examine ground motions for a sequence of earthquakes in oklahoma where assessment of hazard contributions from induced seismicity is of particular interest we aim to empirically calibrate a model driven equation that was derived for central and eastern north america cena so that it will match the observed ground motions of the 2011 prague oklahoma sequence we first show that ground motions in oklahoma decay at a rate similar to the average attenuation observed in the stable continental region of cena we then search for any needed adjustments to the cena source model to match ground motions from the induced seismicity sequence that occurred near prague in 2011 an interesting feature noted in the ground motion analysis is that the stress parameters for the prague mainshock events m 5 are notably higher than those for aftershocks moreover the stress parameter that characterizes the high frequency ground motion decays in both time and space relative to the three largest events the largest events in the prague sequence have similar source parameters to natural cena events of the same magnitude and focal depth but their aftershocks have weaker motions

characteristics mechanism and development tendency of deformation of maoping landslide after commission of geheyan reservoir on the qingjiang river hubei province china abstract based on field investigation of the constituent structure and geological formation of the maoping landslide the authors made an in depth study of the deformation characteristics and triggering mechanism of the reservoir induced slide through comprehensive analysis of the about 13 years observation data the maoping landslide the largest ancient landslide in geheyan reservoir with a volume of 23 5 million m3 is located on the left bank of the qingjiang river 66 km upstream of geheyan dam in april 1993 reservoir inundation reactivated the landslide which resulted in relocation of a village of 290 people since then the landslide body has been experiencing persistent deformation with an observed maximum displacement of 2841 4 mm up to october 2005 therefore further development of deformation of the landslide becomes a great concern for the safety of the reservoir and dam the analysis results show that the maoping landslide is an ancient landslide that is an accumulation of several consequent slides along the bank slope and experienced several secondary slumps in its front in later stages the ongoing deformation of the reactivated landslide is controlled by mechanical properties of materials and hydraulic effects induced by reservoir the slip process is of creep deformation as a whole and appears to be attenuating in later stage which indicates very low possibility of the high speed slip and integral failure of the slide

integrated geophysics and soil gas profiles as a tool to characterize active faults the amer fault example pyrenees ne spain the combined use of geophysical and soil gas composition exploration methods allows to rapidly obtain at relative low cost information that might be related to seismic activity conditions in this study we carried out geochemical soil gas sampling 222rn 220rn and co2 electrical resistivity tomography and seismic refraction profiles in two selected zones near the town of amer in the spanish pyrenees where the presence of recent fractures is evident in the field data analysis clearly reveals anomalous values for each gas at specific positions along the electrical imaging transects geomorphologic and hydrogeologic data and the integration of geophysical data and soil gas measurements indicate that 1 endogene gases radon 222rn and carbon dioxide co2 are released from the meta sedimentary basement rocks across the main fractured zones with higher permeability values while lower cenozoic detrital sedimentary formations act as an impervious boundary 2 sites with highest radon concentrations 52 kbq m 3 coincide with the zones in the amer fault showing more recent geomorphic evidence of activity and more specifically with those areas covered by thinner surficial formations 3 the lowest 222rn values 0 2 0 4 kbq m 3 were recorded just on the master active fault plane this pattern could be explained by a dilution effect resulting from high rates of soil co2 efflux 267 g m 2 day 1 4 soil thoron 220rn activity is maximum 143 kbq m 3 in areas with high surficial fracturing 5 groundwater pumping may cause important distortions in the natural flow dynamics and in the measured concentrations of gases the agreement between the different data geochemical geophysical and hydrogeological and field observations geology and geomorphology leads us to propose a preliminary tectonic gravitational model for the study area

a catchment scale model of mountain stream channel morphologies in southeast australia the position of mountain streams high in the channel network and their proportional dominance mean that channel modifications and adjustments within these systems will have important implications for downstream processes and linkages this study develops an analysis framework for examining the catchment scale distribution of reach morphologies and the relationship among reach type catchment lithology and flow competence in southeast australian mountain streams the analysis framework is applied to three catchments which have contrasting proportions of the two dominant lithologies of the region devonian granites and ordovician metasediments the model successfully delineated 68 of reach types and the resultant spatial maps allowed the effects of stream network position and catchment specific controls on channel morphology to be evaluated maximum lengths of the majority of reach morphology types were in second order streams and the maximum number of morphology types six was present in third order streams with dramatic reductions in reach type variability as the network expands the position of catchment lithology within the channel network structure was recognized as more important than the aerial extent of a particular lithology on the distribution and abundance of reach morphologies the model provides an important tool in the management of channel networks for the protection or restoration of ecological diversity by identifying river segments and tributaries with high morphological diversity

evaluation of trenching ground penetrating radar gpr and electrical resistivity tomography ert for sinkhole characterization this paper explores the suitability and advantages of combining the trenching technique with geophysical surveys ground penetrating radar gpr and electrical resistivity tomography ert for sinkhole characterization in a mantled karst area the approach is applied to two active sinkholes concealed by anthropogenic deposits and formed by contrasting subsidence mechanisms collapse and sagging the ert section acquired across the collapse sinkhole images the clayey fill of the depression as an obvious low resistivity area showing the approximate location of the sinkhole edges spatially dense gpr surveys provide information on the position of the boundaries of the concealed subsidence structures and their three dimensional 3d internal geometry revealing the dominant subsidence mechanism we illustrate the impact of several factors on the quality of the gpr data such as sinkhole size nominal frequency of the antennas antenna shielding and the presence of backfilled excavations and above surface objects trenches provided detailed information on the subsurface structure of the sinkhole subsidence magnitude partitioning of the strain and the position of the sinkhole edges especially when they are deep enough and excavated across the central sector and perpendicular to the boundaries the stratigraphic and structural relationships observed in the trench were then used to infer the spatial evolution of the sinkholes e g enlargement their kinematic behavior episodic versus progressive and to differentiate discrete subsidence events and their associated magnitude numerical dates were used to estimate average subsidence rates and the recurrence of subsidence events such integrated data sets may be used as an objective basis to forecast the future behavior of potentially damaging sinkholes and to assess the associated hazard and risk copyright 2013 john wiley sons ltd

holocene valley aggradation driven by river mouth progradation examples from australia since the end of the post glacial sea level rise 6800 years ago progradation of river mouths into estuaries has been a global phenomenon the responses of upstream alluvial river reaches to this progradation have received little attention here the links between river mouth progradation and holocene valley aggradation are examined for the macdonald and tuross rivers in south eastern australia optical and radiocarbon dating of floodplain sediments indicates that since the mid holocene sea level highstand 6800 years ago vertical floodplain aggradation along the two valleys has generally been consistent with the rate at which each river prograded into its estuary this link between river mouth progradation and alluvial aggradation drove floodplain aggradation for many tens of kilometres upstream of the estuarine limits both rivers have abandoned their main holocene floodplains over the last 2000 years and their channels have contracted a regional shift to smaller floods is inferred to be responsible for this change though a greater relative sea level fall experienced by the macdonald river since the mid holocene sea level highstand appears to have been an additional influence upon floodplain evolution in this valley copyright 2006 john wiley sons ltd

depositional history of estuarine infill during the last postglacial transgression gulf of cadiz southern spain abstract the late pleistocene and holocene evolution of the estuaries in the gulf of cadiz is interpreted for the first time using drill cores logs trenches and 38 new radiocarbon data and the results compared with the shelf the odiel tinto and guadalete rivers deposited conglomerates during a highstand that did not reach the present sea level dated at ca 25 30 ka isotopic stage is 3 corresponding to a relatively humid period in the area rivers incised these coarse grained deposits during the last main lowstand at ca 18 ka when sea level dropped to 120 m and the coastline lay 14 km seawards from the present the erosional surface is a sequence boundary and the flooding surface of the postglacial eustatic rise overlain by the valley fill deposits of the transgressive and highstand phases of the last fourth and fifth order depositional sequences recognised in the shelf the first marine influence in the estuaries during the transgression occurs at 25 30 m at ca 10 000 years bp according to fossil assemblages the transgressed basins changed from brackish to more open marine as the sea rose until ca 6500 years bp when it reached the maximum flooding and the sandy estuarine barriers ceased to retrograde toward the muddy central basins then the rate of eustatic rise decreased drastically and the estuarine filling followed a two fold pattern governed by the progressive change from vertical accretion to lateral centripetal progradation at ca 4000 years bp the fluvial input surpassed the already negligible rate of rise causing partial emergence of tidal flats and spit barriers in the largely filled estuarine basins prevalence of coastal progradation upon vertical accretion at ca 2400 years bp caused accelerated expansion of tidal flats and rapid growth of the sandy barriers further changes since the 16th century reflect widespread anthropic impacts

the upper hawkesbury river new south wales australia a holocene example of an estuarine bayhead delta holocene deposits of the hawkesbury river estuary located immediately north of sydney on the new south wales coast record the complex interplay between sediment supply and relative sea level rise within a deeply incised bedrock confined valley system the present day hawkesbury river is interpreted as a wave dominated estuarine complex divisible into two broad facies zones i an outer marine dominated zone extending 6 km upstream from the estuary mouth that is characterized by a large subtidal sandy flood tidal delta ocean wave energy is partially dissipated by this flood tidal delta so that tidal level fluctuations are the predominant marine mechanism operating further landward ii a river dominated zone that is 103 km long and characterized by a well developed progradational bayhead delta that includes distributary channels levees and overbank deposits this reach of the hawkesbury river undergoes minor tidal level fluctuations and low fluvial runoff during baseflow conditions but experiences strong flood flows during major runoff events fluvial deposits of the hawkesbury river occur upstream of this zone the focus of this paper is the hawkesbury river bayhead delta history of deposition within this delta over the last c 12 ka is interpreted from six continuous cores located along the upper reaches of the hawkesbury river detailed sedimentological analysis of facies whole core x ray analysis of burrow traces and a chronostratigraphic framework derived from 10 c 14 dates reveal four stages of incised valley infilling in the study area 1 before 17 ka bp a 0 1 m thick deposit of coarse grained fluvial sand and silt was laid down under falling to lowstand sea level conditions 2 from 17 to 6 5 ka bp a 5 10 m thick deposit composed of fine grained fluvial sand and silt muddy bayhead delta and muddy central basin deposits developed as the incised valley was flooded during eustatic sea level rise 3 during early highstand between 6 5 and 3 ka bp a 3 8 m thick bed of interbedded muddy central basin deposits and sandy river flood deposits formed in association with maximum flooding and progradation of sandy distributary mouth bar deposits commenced 4 since 3 ka bp fluvial deposits have prograded toward the estuary mouth in distributary mouth bar interdistributary bay and bayhead delta plain environments to produce a 5 15 m thick progradational to aggradational bayhead delta deposit at the mouth of the hawkesbury estuary subaqueous fluvial sands interfinger with and overlie marine sands the hawkesbury river bayhead delta depositional succession provides an example of the potential for significant variation of facies within the estuarine to fluvial segment of incised valley systems

reconstructing the geochronological evolution of large landslides by means of the trenching technique in the yesa reservoir spanish pyrenees abstract detailed geomorphological mapping has revealed that the slopes upstream of the yesa dam are affected by several flysch landslides the largest landslides correspond to la refaya rotational slide 11 million m3 situated just upstream of the spillway and el vertedero translational slide 6 million m3 located 1 5 km upstream of the dam a portion of el vertedero landslide 3 million m3 was reactivated in 2006 due to overloading caused by an earth heap a higher earth dam will be built on the downstream side of the existing gravity concrete dam to raise the maximum water level of the reservoir by 23 m the retrodeformation analysis of the deposits exposed in two trenches excavated in the upper part of these landslides together with the obtained absolute ages c14 and osl have provided information on the kinematics and evolution of these slope movements the main findings derived from the 45 m long trench dug in the closed depression developed at the foot of the head scarp of la refaya landslide include 1 the landslide is older than 12 ka and has undergone a cumulative rotation higher than 17 yielding a mean rotation rate of about 1 4 millennium 2 most of the rotation 14 occurred before 5 8 ka and according to the trench stratigraphy the kinematics of the landslide has been dominated by progressive displacement no evidence of catastrophic reactivation has been found the 45 m long trench excavated across the scarp and bench situated at the head of the non reactivated portion of el vertedero translational slide reveals that 1 the landslide is older than 38 ka 2 the trenched portion has undergone at least one reactivation subsequent to 20 ka and has remained inactive for a long time as suggested by the highly degraded bedrock scarp with a slope of 18 compared to the 60 dip of the underlying failure plane based on this study corrective measures with an estimated cost of 11 5 million euros have been designed for this slope the investigation illustrates the usefulness and cost effectiveness of the trenching technique allied with geochronological methods to obtain information on the precise limits age failure mechanism kinematics progressive vs episodic displacement movement rate and chronological evolution of landslides

localization and characterization of an active fault in an urbanized area in central guatemala by means of geoelectrical imaging article i nfo article history the polochic and motagua faults define the active plate boundary between the north american and caribbean plates in central guatemala a splay of the polochic fault traverses the rapidly growing city of san miguel uspantan that is periodically affected by destructive earthquakes this fault splay was located using a 2d electrical resistivity tomography ert survey that also characterized the fault damage zone and evaluated the thickness and nature of recent deposits upon which most of the city is built ert images show the fault as a 50 m wide near vertical low resistivity anomaly bounded within a few meters by high resistivity anomalies forward modeling reproduces the key aspects of the observed electrical resistivity data with remarkable fidelity thus defining the overall location geometry and internal structure of the fault zone as well as the affected lithologies our results indicate that the city is constructed on a 20 m thick surficial layer consisting of poorly consolidated highly porous water logged pumice this soft layer is likely to amplify seismic waves and to liquefy upon moderate to strong ground shaking the electrical conductivity as well as the major element chemistry of the groundwater provides evidence to suggest that the local aquifer might at least in part be fed by water rising along the fault therefore the potential threat posed by this fault splay may not be limited to its seismic activity per se but could be compounded its potential propensity to enhance seismic site effects by injecting water into the soft surficial sediments the results of this study provide the basis for a rigorous analysis of seismic hazard and sustainable development of san miguel uspantan and illustrate the potential of ert surveying for paleoseismic studies

differentiating between gravitational and tectonic faults by means of geomorphological mapping trenching and geophysical surveys the case of the zenzano fault iberian chain n spain abstract the zenzano fault scarp has been developed on the top of a 475 m high erosional escarpment underlain by an upper brittle sequence and a lower halite bearing evaporitic formation the 1850 m long fault with a maximum displacement of 45 m and parallel to the escarpment has offset the back of a dip slope generating an antislope scarp with prominent triangular facets up to 38 m high and obstructing consequent transverse drainages defeated streams both gravitational and tectonic interpretations were previously proposed for this active surface rupture the fault scarp has been investigated by detailed geological and geomorphological mapping geophysical surveys gpr and ert and two trenches excavated across the fault in disrupted drainages the geophysical profiles clearly imaged the fault helping to site the trenches and roughly estimate the thickness of the deposits accumulated in the downthrown block although the maximum displacement to length ratio dmax l of the fault fall within the range of tectonic faults of similar length according to the world database the geological and geomorphological context together with several parameters reveal that this structure corresponds to a gravitational failure 1 anomalously high vertical displacement per event 1 4 m 2 high apparent vertical slip rate 0 6 mm year and 3 short recurrence interval of faulting events the negligible horizontal displacement component on the dip slip fault as well as the presence of very large caprock collapse sinkholes and saline springs strongly suggest that interstratal karstification of the halite bearing evaporites has played a primary role in the development of the gravitational failure the formation of this morphostructure has been favoured by pre existing tectonic faults erosional unloading related to the removal of an overburden ca 800 m thick and enhanced groundwater recharge due to the blockage of the drainage this work illustrates that the proposed multidisciplinary approach allows the identification of features and calculation of parameters that may help to elucidate whether an active failure has a gravitational or a tectonic origin

landslides triggered by the 1949 khait earthquake tajikistan and associated loss of life abstract earthquake triggered landslides are a major geological hazard in central asia in july 1949 the m7 4 khait earthquake triggered many hundreds of landslides in a mountainous region near the southern limit of the tien shan mountains central tajikistan these landslides involved widespread rock slope failure as well as large numbers of flowslides in loess that mantles the steep slopes of the region in the yasman valley hundreds of loess landslides coalesced to form a massive loess flow est vol 245 mm 3 that travelled up to 20 km on a slope of only 2 in an adjacent valley the khait landslide involved transformation of an earthquake triggered rockslide into a very rapid flow by the entrainment of saturated loess into its movement it travelled 7 41 km over a vertical distance of 1421 m with an estimated average velocity of 30 m s we estimate its volume as 75 mm 3 an order of magnitude less that previously published estimates the khait landslide was simulated using dan the number of casualties due to earthquake triggered landslides in the epicentral region was considerable approximately 4000 people were killed in the yasman valley loess flow as 20 villages kishlaks were overwhelmed in the khait landslide alone we estimate ca 800 people lost their lives when the villages of khait and khisorak were overrun by rapidly moving debris our data indicates that a total of approximately 7200 people were killed by earthquake triggered landslides in the epicentral region of the khait earthquake and that in terms of loss of life the 1949 yasman valley loess flow was one of the most destructive landslides in recent history

shaking from injection induced earthquakes in the central and eastern united states abstract in this study i consider the ground motions generated by 11 moderate m w 4 0 5 6 earthquakes in the central and eastern united states that are thought or suspected to be induced by fluid injection using spatially rich intensity data from the u s geological survey did you feel it system i show the distance decay of intensities for all events is consistent with that observed for tectonic earthquakes in the region but for all of the events intensities are lower than the values predicted from an intensity prediction equation that successfully characterizes intensities for regional tectonic events i introduce an effective intensity magnitude m ie defined as the magnitude that on average would generate a given intensity distribution for all 11 events m ie is lower than the event magnitude by 0 4 1 3 magnitude units with an average difference of 0 82 units this suggests stress drops of injection induced earthquakes are systematically lower than tectonic earthquakes by an estimated factor of 2 10 however relatively limited data suggest intensities for epicentral distances less than 10 km are more commensurate with expectations for the event magnitude which can be reasonably explained by the shallow focal depth of the events the results suggest damage from injection induced earthquakes will be especially concentrated in the immediate epicentral region

holocene stratigraphy and geomorphological evolution of the aegean coastal plains of anatolia abstract three main stages can be distinguished in the sedimentary development and geomorphological formation of the present delta plains on the aegean coast of turkey the early holocene is characterized by post glacial transgression and dependent sedimentation the middle holocene was the period when sea level reached the present level and apart from small fluctuations stopped rising alluviation and deltaic progradation were prevalent during this transition period from marine to terrestrial environments as for the late holocene deltaic progradation slowed down and delta plains were covered by floodplain sediments these characteristics can be observed in the same sequence throughout the aegean coast of turkey

catastrophic landslide induced by typhoon morakot shiaolin taiwan abstract typhoon morakot induced the catastrophic and deadly shiaolin landslide in southern taiwan on 9 august 2009 resulting in more than 400 casualties we undertook a geological and geomorphological investigation with the aim of reconstructing the events leading up to this landslide and to clarify factors that contributed to its development cumulative rainfall reached up to 1676 5 mm in about three days under the influence of the typhoon and the shiaolin landslide with a volume of 25 106 m3 occurred one day after the peak in rainfall intensity the landslide occurred on a dip slope overlying late miocene to early pliocene sedimentary rocks consisting of silty shale massive mudstone and sandstone it started as a rockslide in the upper third of the landslide area and transformed into a rock avalanche that crossed a series of terraces and displaced or buried the village below it buried the riverbed of the chishan river and ran up the opposite slope creating a landslide dam 60 m high which was breached about 1 h and 24 min later flooding the village the velocity of the landslide is estimated to have been 20 4 to 33 7 m s 1 and its apparent friction angle was 14 which indicates its high mobility the detachments in the source area consist of combinations of bedding planes and joints or faults the landslide was preceded by gravitational deformation which appeared as hummocky landforms before the landslide and as buckle folds exposed after the event the landslide deposits consist of fragments of mudstone shale and sandstone as well as clayey material at its base this clayey material consisting of illite chlorite quartz feldspar and calcite is assumed to have strongly influenced the long rapid runout

sediment facies and late holocene progradation of the mekong river delta in bentre province southern vietnam an example of evolution from a tide dominated to a tide and wave dominated delta abstract the mekong river delta southern vietnam is a typical mixed tide and wave energy delta with a wide delta plain formed during the last 6 ka and is one of the largest deltas in the world three cores were taken from bentre province in the lower delta plain with the objective to describe the sediment facies and to clarify the changes from tide dominated to tide wave dominated delta of the mekong river delta during the late holocene three cores bt1 bt2 and bt3 were obtained in 1997 holocene sediments in bt1 and bt3 with thickness ranging from 10 to 20 m were mainly composed of deltaic sediments unconformably overlying the late pleistocene sediments the bt2 core however consisted of transgressive estuarine sediments covered by deltaic sediments infilling the paleo mekong river incised valley which is more than 70 m deep and was formed during the last glacial period the deltaic sediment facies and succession in the bt2 and bt3 cores taken from the outer delta plain with beach ridges were different from those of the bt1 core taken from the inland delta plain the bt2 and bt3 cores provide a good example of tide and wave dominated delta sediments and were characterized by a coarsening upward delta front facies covered by a fining upward subtidal to intertidal flat facies followed by a coarsening upward foreshore dune facies these changes from the inland delta plain to the beach ridge delta plain were accompanied by changes in progradation rates and subaqueous delta topography caused by increased wave influence

actively growing anticlines beneath catania from the distal motion of mount etna s decollement measured by sar interferometry and gps we used sar interferometry and gps to measure the rise of an anticline beneath the urban area of catania italy which originates from outward thrusting above the basal decollement of etna volcano the anticline grows at a rate of over 0 015 m a 1 of se thrusting and about 0 007 m a 1 of relative uplift by relating this growth to the simultaneous extension measured at the summit of the volcano we demonstrate the occurrence of active volcanic spreading this process may exert a control on eruptions earthquakes sector collapses and landslides

late quaternary environmental changes in eastern and central australia and their climatic interpretation abstract the march of environmental changes in eastern australia from the last interglacial to the holocene is reviewed palynologic evidence suggests that forest composition fluctuated substantially during oxygen isotope oi substages 5a to 5e but physical evidence for this period is as yet poorly defined during oi stage 3 and possibly part of 4 inland lakes were larger and the hydrologic balance was wetter than at any time since conditions were coldest and dune activity was maximal throughout the continent during oi stage 2 but driest conditions as judged from lake levels occurred at the termination of the pleistocene when temperatures were rising rapidly lags between changes of boundary conditions and responses of natural systems are clearly seen in holocene behaviour of coasts and reefs and the effects of extreme events rather than climatic changes are seen in some sedimentary sequences establishment of the chronology of deposits older than about 35 ka and forging links between the terrestrial and deep sea records are major challenges for future research

oklahoma experiences largest earthquake during ongoing regional wastewater injection hazard mitigation efforts the 3 september 2016 mw 5 8 pawnee earthquake was the largest recorded earthquake in the state of oklahoma seismic and geodetic observations of the pawnee sequence including precise hypocenter locations and moment tensor modeling shows that the pawnee earthquake occurred on a previously unknown left lateral strike slip basement fault that intersects the mapped right lateral labette fault zone the pawnee earthquake is part of an unprecedented increase in the earthquake rate in oklahoma that is largely considered the result of the deep injection of waste fluids from oil and gas production if this is indeed the case for the m5 8 pawnee earthquake then this would be the largest event to have been induced by fluid injection since 2015 oklahoma has undergone wide scale mitigation efforts primarily aimed at reducing injection volumes thus far in 2016 the rate of m3 and greater earthquakes has decreased as compared to 2015 while the cumulative moment or energy released from earthquakes has increased this highlights the difficulty in earthquake hazard mitigation efforts given the poorly understood long term diffusive effects of wastewater injection and their connection to seismicity

alluvial sedimentation rates from southeastern australia indicate post european settlement landscape recovery increased catchment sediment yields are common following the introduction of european style agriculture to relatively undisturbed landscapes catchment erosion rates generally increase immediately after disturbance and then decline over time consequently where a catchment currently sits along this disturbance recovery sequence will strongly influence future catchment sediment yields and river morphology in this study field stratigraphy optical dating and hydraulic modelling are used to investigate changes in catchment sediment yield and storage in the lake burragorang catchment in australia with emphasis placed upon changes occurring since european settlement in a d 1820 on the southern tablelands and the upper cox s river subcatchment a large volume of sediment was liberated by gully erosion early in the post settlement period much of which was deposited at break of slope positions below the catchment s headwaters or stored in alluvial benches adjacent to the channel but within the confines of older holocene alluvium a lack of substantial sediment deposition over the last 20 to 40 years is evidence that catchment sediment yields have strongly declined this is consistent with both reduced erosion rates and re aggradation of the incised gullies that in their erosive phase dominated the catchment s post settlement sediment flux collectively these characteristics indicate the catchment is undergoing a phase of landscape recovery

the significance of large sediment supply active tectonism and eustasy on margin sequence development late quaternary stratigraphy and evolution of the ganges brahmaputra delta abstract borehole data from the ganges brahmaputra delta system unveil an intriguing late quaternary history controlled by immense sediment discharge tectonics and eustasy sea level first intersected a major portion of the lowstand surface 10 000 11 000 cal yr bp marking the onset of sediment trapping and delta growth despite rapid sea level rise 1 cm yr sediment load was sufficient to maintain relative shoreline stability during this time by 7000 cal yr bp accommodation was quickly infilled with slowed sea level rise leading to upstream channel migration and widespread dispersal of sands this forced coastal progradation along the western delta front where the ganges was situated and much of the river s fine grained discharge bypassed the subaerial delta and formed a prograding deltaic clinoform on the shelf concurrently brahmaputra sediments were sequestered to an inland tectonic basin thus starving the adjacent shoreline and leading to transgression along the eastern delta by 5000 cal yr bp the two rivers had migrated or changed course to discharge along the eastern delta shoreline which began to prograde into what is now the modern river mouth estuary present delta configuration appears to have developed by 3000 cal yr bp evolution of the tectonically active ganges brahmaputra g b system reveals important similarities and differences with other deltas overall facies succession follows that of basic models progressing from an alluvial valley to coastal marine delta front to a prograding subaerial delta plain however the timing thickness and controls of these deposits differ immense sediment discharge from the ganges and brahmaputra rivers allowed initial delta growth 2000 3000 yr earlier than the global average despite debouching onto a canyon incised high energy margin subsequently a thick 50 m transgressive systems tract was formed during the early holocene phase of delta aggradation contrasting with extensive shoreline retreat documented along most margins highstand progradation of coastal and shelf sequences ensued by the middle holocene but subsiding inland basins also favored accumulation of a thick to 40 m highstand sequence in the lower floodplains unlike many other delta systems subsidence in the subaerial g b delta is not dominated by compaction but rather by plate driven tectonic processes that generate rates up to 4 mm year overall the huge sediment load tectonic subsidence major seismic events and a nearshore canyon system have led to widespread sediment dispersal and sequence formation across the subaerial delta shelf and deep sea bengal fan throughout the late quaternary

comparison of gpr 2d resistivity and traditional techniques for the subsurface exploration of the oschingen landslide swabian alb germany abstract numerous rotational and translational slides of different sizes cause considerable economic damage in the swabian alb sw germany and are a challenge for risk assessment the oschingen landslide is a typical example for landslides occurring along the escarpment lithology consists of jurassic sedimentary rocks involving clays overlain by marls and limestones a combination of traditional methods drilling mapping inclinometers and geophysical techniques 2d resistivity ert ground penetrating radar gpr was applied to gain knowledge about the thickness and internal structure of the landslide the drillings and penetration tests provided point information on landslide extent structure and material involved in general all inclinometers showed very little movement if at all the gpr results were affected by strong signal attenuation and by overhead reflections from the nearby woods despite these general obstacles for the application of gpr on landslides near surface sediment structures were detected in the 2d resistivity sections higher resistive limestone blocks reaching 10 15 m in thickness could be clearly distinguished from the underlying bedrock the detailed two dimensional data of the electrical resistivity tomography ert along with the rather high survey speed turned out to be the best choice to gain detailed spatial information on thickness and extent of the slope movement the measured profiles coincide with the gpr data and correspond to borehole data surprisingly all results from the applied methods clearly detected the absence of large landslide blocks in the north west of the study area this finding could not be concluded from local geomorphology of this area regarding the current landslide displacement derived from the inclinometer measurements the large landslide blocks seem to be dormant during the measured period

zonation of the landslide hazards in the forereservoir region of the three gorges project on the yangtze river on the basis of the investigation and statistic analysis of the landslide hazards in the forereservoir region of the three gorges project on the yangtze river the major factors that are found to have affected the slope stabilities are outlined and a zonation of landslide hazards of the region is made using an integrated information model it is divided into destructive disastrous slightly disastrous likely disastrous and essentially non disastrous areas the first two cover an area of less than 5 of the total region and are at a distance of more than 20 km from the three gorges dam and so a landslide over there will impose no direct impact to the tgp but may effect to some degree the navigation of the yangtze river and nearby highway transportation reservoir slopes and building of cities and towns