seismic and aseismic deformation associated with the 1952 kern county california earthquake and relationship to the quaternary history of the white wolf fault synthesis of geodetic geologic and seismic data from the white wolf fault california indicates that the fault separates an area of late quaternary and continuing rapid uplift in the tehachapi mountains and transverse ranges from even more rapid subsidence in the southern san joaquin valley on july 21 1952 rupture of the white wolf fault produced the ml 7 2 kern county earthquake we used the aftershock zone to delimit the size of the faulted slip surface and applied constraints imposed by the known 1952 1953 horizontal shear strains to model the measured coseismic vertical displacements with an elastic dislocation model a curved fault trace with decreasing fault depth 27 to 10 km from the surface vertically to the base slip 3 to 1 m and dip 75 to 20 from the 1952 epicenter at the southwest end of the fault toward the northeast provides the fit most consistent with the geodetic record the measured seismic moment the fault plane solution and the pattern of surface rupture two short releveled lines near the 1952 epicenter tilted 4 and 17 rad down to the north from 5 10 years before the earthquake the preseismic tilts differ significantly from ten other surveys of these lines left lateral fault crossing shear strain from 0 2 20 years before the quake was two times greater than both preseismic off fault strains and the post seismic fault crossing strains during the first seven years after the earthquake aseismic deformation was negligible from 1959 to 1972 uplift reached 160 mm over an area larger than the aftershock zone rising first in the epicentral region and then at the northeast end of the fault this was unaccompanied by any surface fault slip reconstruction of the vertical separation on the white wolf fault from late quaternary and late miocene stratigraphic marker beds shows that the rate of reverse fault slip increased forty fold from 0 1 0 2 mm yr to 3 9 mm yr between the past 10 15 m y and the most recent 0 6 1 2 m y we estimate a 170 to 450 yr average recurrence interval for earthquakes on the white wolf fault with slip equivalent to that in 1952 the 1952 earthquake appears to be characteristic of the quaternary record of fault displacement in the increase in white wolf slip toward the san andreas fault the ratio of reverse to lateral slip 1 3 1 and the ratio of vertical fault slip to emergence of the hanging wall block 3 1 the 8500 m deep sedimentary basin on the down thrown block cannot be explained by repeated slip of the white wolf fault in an elastic medium

upward groundwater flow in boils as the dominant mechanism of salinization in deep polders the netherlands as upward seepage of saline groundwater from the upper aquifer is leading to surface water salinization of deep polders in the netherlands we monitored the processes involved in the noordplas polder a typical deep polder our results show three types of seepage 1 diffuse seepage through the holocene confining layer 2 seepage through paleochannel belts in the holocene layer and 3 intense seepage via localized boils they differ with regard to seepage flux chloride concentration and their location in the polder thus their contributions to surface water salinization also differ permeable sandy paleochannel belts cut through the lower part of the holocene layer resulting in higher seepage fluxes than the diffuse seepage through the holocene layer where there are no paleochannels the average chloride concentration of paleochannel seepage is about 600 mg l which is sixfold higher than the average concentration of diffuse seepage the highest seepage fluxes and chloride concentrations are found at boils which are small vents in the holocene layer through which groundwater preferentially discharges at high velocities this results in upconing of deeper and more saline groundwater which produces an average chloride concentration of 1100 mg l despite the fact that seepage fluxes are difficult to measure we were able to calculate that boils contribute more than 50 of the total chloride load entering the noordplas polder and they therefore form the dominant salinization pathway

multi temporal uav data for automatic measurement of rill and interrill erosion on loess soil the fragile landscape of the north european loess belt is prone to soil erosion due to soil properties and intense land use of the fertile region exact measurement of surface changes with high temporal and spatial resolution over large areas is necessary to quantify and understand rill and interrill erosion processes high resolution aerial imagery acquired by an unmanned aerial vehicle uav is used to automatically generate precise digital surface models dsms of high spatial resolution by applying structure from motion image processing tools during an investigation period of ten months a 600 m2 field plot is observed during four field campaigns a stable reference system is established for multi temporal comparison the overall accuracy of the dsms generated from uav images is less than 1 cm verified by comparison with terrestrial laser scanner tls data furthermore a method for automatic rill extraction and rill parameter calculation is developed which enables objective rill description with cm accuracy and resolution soil surface roughness and rill development as well as volumetric quantifications are analysed for multi temporal change detection surface changes during winter season are controlled by soil consolidation crusting and sheet erosion during rainy spring season sheet erosion and rill incision occur two thunderstorms in summer season cause dominant rill erosion erosion rills are more dominantly deepening than widening from to 2 to 4 cm depth and from 17 to 23 cm width resulting in average per rill erosion values of 0 03 and 0 07 m3 respectively an orientation dependent lateral rill shift is revealed implying rill widening in eastern direction due to dominant winds from the west volumetric quantifications indicate high erosion volumes reaching up to 121 tha 1 during the summer events highest erosion volumes are due to rill erosion rather than interrill erosion copyright 2014 john wiley sons ltd

groundwater discharge along a channelized coastal plain stream in the coastal plain of the southeastern usa streams have commonly been artificially channelized for flood control and agricultural drainage however groundwater discharge along such streams has received relatively little attention using a combination of stream and spring flow measurements spring temperature measurements temperature profiling along the stream bed and geologic mapping we delineated zones of diffuse and focused discharge along little bayou creek a channelized first order perennial stream in western kentucky seasonal variability in groundwater discharge mimics hydraulic head fluctuations in a nearby monitoring well and spring discharge fluctuations elsewhere in the region and is likely to reflect seasonal variability in recharge diffuse discharge occurs where the stream is incised into the semi confined regional gravel aquifer which is comprised of the mounds gravel focused discharge occurs upstream where the channel appears to have intersected preferential pathways within the confining unit seasonal fluctuations in discharge from individual springs are repressed where piping results in bank collapse thereby focused discharge can contribute to the morphological evolution of the stream channel

quantifying submerged fluvial topography using hyperspatial resolution uas imagery and structure from motion photogrammetry quantifying the topography of rivers and their associated bedforms has been a fundamental concern of fluvial geomorphology for decades such data acquired at high temporal and spatial resolutions are increasingly in demand for process oriented investigations of flow hydraulics sediment dynamics and in stream habitat in these riverine environments the most challenging region for topographic measurement is the wetted submerged channel generally dry bed topography and submerged bathymetry are measured using different methods and technology this adds to the costs logistical challenges and data processing requirements of comprehensive river surveys however some technologies are capable of measuring the submerged topography through water photogrammetry and bathymetric lidar are capable of reasonably accurate measurements of channel beds in clear water whilst the cost of bathymetric lidar remains high and its resolution relatively coarse the recent developments in photogrammetry using structure from motion sfm algorithms promise a fundamental shift in the accessibility of topographic data for a wide range of settings here we present results demonstrating the potential of so called sfm photogrammetry for quantifying both exposed and submerged fluvial topography at the mesohabitat scale we show that imagery acquired from a rotary winged unmanned aerial system uas can be processed in order to produce digital elevation models dems with hyperspatial resolutions c 0 02 m for two different river systems over channel lengths of 50 100 m errors in submerged areas range from 0 016 m to 0 089 m which can be reduced to between 0 008 m and 0 053 m with the application of a simple refraction correction this work therefore demonstrates the potential of uas platforms and sfm photogrammetry as a single technique for surveying fluvial topography at the mesoscale defined as lengths of channel from c 10 m to a few hundred metres this article is protected by copyright all rights reserved

optimisation of uavs sfm data collection in aeolian landform morphodynamics a case study from the gonghe basin china uavs sfm unmanned aerial vehicles structure from motion systems can generate high resolution 3d topographic models of aeolian landforms to explore the optimisation of uavs sfm for use in aeolian landform morphodynamics this study tested flight parameters for two contrasting aeolian landform areas free dune and blowout to assess the 3d reconstruction accuracy of the uavs survey compared with field point measurements using differential rtk gps real time kinematic global positioning system the results reveal the optimum uavs sfm flight set up at the free dune site was flying height 74 m camera tilt angle 90 photo overlap ratio 85 70 heading sideways the horizontal vertical location error was around 0 028 0 055 m and 0 053 0 069 m respectively and a point cloud density of 463 m3 was found to generate a clear texture using these flying parameters for the 20m deep blowout the optimum set up with highest accuracy and the lowest cliff texture distortion was flying height 74 m combined camera tilt angle 90 and 60 photo overlap ratio 85 70 heading sideways and an evenly distributed gcps ground control points density of 42 km2 using these flying parameters when the depth of the blowouts exceeded 40 m the optimum flight survey parameters changed slightly to account for more challenging cliff texture generation flying height 80 m with 90 and 60 combined camera tilt angle gcps density 63 km2 to generate horizontal and vertical location error of 0 024 m and 0 050 m respectively and point cloud density of 2597 11 m3 the main external factors that affect the successful 3d reconstruction of aeolian landforms using uavs sfm are the weather conditions manipulation errors and instrument system errors the uavs sfm topographic monitoring results demonstrate that uavs provide a viable and robust means for aeolian landform morphodynamics monitoring importantly the rapid and high precision 3d reconstruction processes were significantly advanced using the optimal flight parameters reported here

ice cored moraine degradation mapped and quantified using an unmanned aerial vehicle a case study from a polythermal glacier in svalbard ice cored lateral frontal moraines are common at the margins of receding high arctic valley glaciers but the preservation potential of these features within the landform record is unclear recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de ice this is important because high arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid latitudes this study uses sfm structure from motion photogrammetry and a combination of archive aerial and uav unmanned aerial vehicle derived imagery to investigate the degradation of an ice cored lateral frontal moraine at austre lovenbreen svalbard across the study area as a whole over an 11 year period the average depth of surface lowering was 1 75 0 89 m the frontal sections of the moraine showed low or undetectable rates of change spatially variable rates of surface lowering are associated with differences in the quantity of buried ice within the structure of the moraine morphological change was dominated by surface lowering with limited field evidence of degradation via back wastage this permits the moraine a greater degree of stability than previously observed at other sites in svalbard it is unclear whether the end point will be a fully stabilised ice cored moraine in equilibrium with its environment or an ice free lateral frontal moraine complex controls on geomorphological change e g topography and climate and the preservation potential of the lateral frontal moraine are discussed the methods used by this research also demonstrate the potential value of sfm photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub disciplines

how fast does tufa grow very high resolution measurement of the tufa growth rate on artificial substrates by the development of a contactless image based modelling device

characterizing preferential groundwater discharge through boils using temperature summary in the netherlands preferential groundwater discharge trough boils is a key process in the salinization of deep polders previous work showed that boils also influence the temperature in the subsurface and of surface water this paper elaborates on this process combining field observations with numerical modeling as is the case for salinity a distinct anomaly in the subsurface and surface water temperature can be attributed to boils lines of equal temperature are distorted towards the boil which can be considered as an upconing of the temperature profile by analogy of the upconing of a fresh saltwater interface the zone of this distortion is limited to the immediate vicinity of the boil being about 5 m in the aquitard which holds the boil s conduit or maximum a few dozens of meters in the underlying aquifer in the aquitard heat transport is conduction dominated whereas this is convection dominated in the aquifer the temperature anomaly differs from the salinity anomaly by the smaller radius of influence and faster time to reach a new steady state of the former boils discharge water with a temperature equal to the mean groundwater temperature this influences the yearly and diurnal variation of ditch water temperature in the immediate vicinity of the boil importantly but also the temperature in the downstream direction temporary nature of the boil e g stability of the conduit discharge rate uncertainty on the 3d construction of the conduit and heterogeneity of the subsoil make it unlikely that temperature measurements can be interpreted further than a qualitative level

incorporating seepage losses into the unsteady streamflow equations for simulating intermittent flow along mountain front streams 1 seepage losses along numerous mountain front streams that discharge intermittently onto alluvial fans and piedmont alluvial plains are an important source of groundwater in the basin and range province of the western united states determining the distribution of seepage loss along mountain front streams is important when assessing groundwater resources of the region seepage loss along a mountain front stream in northern nevada was evaluated using a one dimensional unsteady streamflow model seepage loss was incorporated into the spatial derivatives of the streamflow equations because seepage loss from streams is dependent on stream depth wetted perimeter and streambed properties a two dimensional variably saturated flow model was used to develop a series of relations between seepage loss and stream depth for each reach this method works when streams are separated from groundwater by variably saturated sediment two periods of intermittent flow were simulated to evaluate the modeling approach the model reproduced measured flow and seepage losses along the channel seepage loss in the spring of 2000 was limited to the upper reaches on the alluvial plain and totaled 196 000 m3 whereas 64 of the seepage loss in the spring of 2004 occurred at the base of the alluvial plain and totaled 273 000 m3 a greater seepage loss at the base of the piedmont alluvial plain is attributed to increased streambed hydraulic conductivity caused by less armoring of the channel the modeling approach provides a method for quantifying and distributing seepage loss along mountain front streams that cross alluvial fans or piedmont alluvial plains

earthquakes quaternary faults and seismic hazard in california data describing the locations slip rates and lengths of quaternary faults are the primary basis in this work for constructing maps that characterize seismic hazard in california the expected seismic moment m0e and the strength of ground shaking resulting from the entire rupture of each mapped fault or fault segment are estimated using empirical relations between seismic moment m0 rupture length source to site distance and strong ground motions assuming a fault model whereby the repeat time t of earthquakes on each fault equals m0e m0g where the moment rate m0g is proportional to fault slip rate it is observed that the moment frequency distribution of earthquakes predicted from the geologic data agrees well with the distribution determined from a 150 year historical record the agreement is consistent with the argument that the geologic record of quaternary fault offsets contains information sufficient to predict the average spatial and size distribution of earthquakes through time in california the estimates of t for each fault are the foundation for constructing maps that depict the average return period of 0 1g peak horizontal ground accelerations and the horizontal components of peak acceleration peak velocity and the pseudovelocity response at 1 period and 5 damping expected to occur at the level of 0 1 probability during a 50 year period of time a map is also formulated to show the probability that 0 1g horizontal ground accelerations will occur during the next 50 years the maps serve to illustrate the potential value of quaternary fault studies for assessing seismic hazard interpretation of available slip rates indicates that the largest and most frequent occurrence of potentially destructive strong ground motions are associated principally with the san andreas san jacinto calaveras hayward and ventura basin fault zones other regions of similarly high hazard may yet remain unrecognized this inadequacy results primarily from an incomplete data set numerous faults for example are mapped along the coastal region of northern california and within the modoc plateau but relatively few studies relating to fault slip rate are reported a similar problem exists for other stretches of coastal california where marine reflection studies provide evidence of active faulting offshore yet yield little or no information of fault slip rate geological and geophysical field studies can work to remove these deficiencies a concerted effort to locate and define rates of activity on all faults in california is the most promising means to further quantify present levels of seismic hazard in california

high resolution mapping of supra glacial drainage pathways reveals link between micro channel drainage density surface roughness and surface reflectance this paper reports on the use of a small unmanned aerial vehicle suav carrying a standard compact camera to construct a high resolution orthomosaic om and digital elevation model dem over the lower reaches of the glacier midtre lovenbreen svalbard structure from motion sfm techniques were used to build the om and dem and together these reveal insights into the nature of supra glacial drainage major meandering supra glacial drainage pathways show clear dynamism via meander cutoffs and abandoned channels in addition the imagery reveals a very extensive network of smaller channels that may well carry substantial amounts of water this network of channels is in part controlled by the structure of the glacier but in turn these channels have a significant impact on the ice surface roughness of the ice surface is higher where channels are most extensive in addition we find a relationship between channel density and surface reflectance such that greater channel density is associated with lower reflectance values given the role of surface reflectance and roughness in the energy balance of glaciers it is therefore apparent that extensive networks of small supra glacial channels across such glaciers have the potential to have an important impact on energy exchanges between the atmosphere and the ice surface copyright 2015 john wiley sons ltd

high resolution monitoring of himalayan glacier dynamics using unmanned aerial vehicles himalayan glacier tongues are commonly debris covered and they are an important source of melt water however they remain relatively unstudied because of the inaccessibility of the terrain and the difficulties in field work caused by the thick debris mantles observations of debris covered glaciers are therefore scarce and airborne remote sensing may bridge the gap between scarce field observations and coarse resolution space borne remote sensing in this study we deploy an unmanned aerial vehicle uav before and after the melt and monsoon season may and october 2013 over the debris covered tongue of the lirung glacier in nepal based on stereo imaging and the structure for motion algorithm we derive highly detailed ortho mosaics and digital elevation models dems which we geometrically correct using differential gps observations collected in the field based on dem differencing and manual feature tracking we derive the mass loss and the surface velocity of the glacier at a high spatial accuracy on average mass loss is limited and the surface velocity is very small however the spatial variability of melt rates is very high and ice cliffs and supra glacial ponds show mass losses that can be an order of magnitude higher than the average we suggest that future research should focus on the interaction between supra glacial ponds ice cliffs and englacial hydrology to further understand the dynamics of debris covered glaciers finally we conclude that uav deployment has large potential in glaciology and it may revolutionize methods currently applied in studying glacier surface features

assessing the performance of structure from motion photogrammetry and terrestrial lidar for reconstructing soil surface microtopography of naturally vegetated plots soil microtopography is a property of critical importance in many earth surface processes but is often difficult to quantify advances in computer vision technologies have made image based three dimensional 3d reconstruction or structure from motion sfm available to many scientists as a low cost alternative to laser based systems such as terrestrial laser scanning tls while the performance of sfm at acquiring soil surface microtopography has been extensively compared to that of tls on bare surfaces little is known about the impact of vegetation on reconstruction performance this article evaluates the performance of sfm and tls technologies at reconstructing soil microtopography on 6 m 2 m erosion plots with vegetation cover ranging from 0 to 77 results show that soil surface occlusion by vegetation was more pronounced with tls compared to sfm a consequence of the single viewpoint laser scanning strategy adopted in this study on the bare soil surface elevation values estimated with sfm were within 5 mm of those from tls although long distance deformations were observed with the former technology as vegetation cover increased agreement between sfm and tls slightly degraded but was significantly affected beyond 53 of ground cover detailed semivariogram analysis on meter square scale surface patches showed that tls and sfm surfaces were very similar even on highly vegetated plots but with fine scale details and the dynamic elevation range smoothed out with sfm errors in the tls data were mainly caused by the distance measurement function of the instrument especially at the fringe of occlusion regions where the laser beam intersected foreground and background features simultaneously from this study we conclude that a realistic approach to digitizing soil surface microtopography in field conditions can be implemented by combining strengths of the image based method simplicity and effectiveness at reconstructing soil surface under sparse vegetation with the high accuracy of tls like technologies copyright 2015 john wiley sons ltd

from experimental plots to experimental landscapes topography erosion and deposition in sub humid badlands from structure from motion photogrammetry in the last decade advances in surveying technology have opened up the possibility of representing topography and monitoring surface changes over experimental plots 10 m2 in high resolution 103 points m 1 yet the representativeness of these small plots is limited with structure from motion sfm and multi view stereo mvs techniques now becoming part of the geomorphologist s toolkit there is potential to expand further the scale at which we characterise topography and monitor geomorphic change morphometrically moving beyond previous plot scale work using terrestrial laser scanning tls surveys this paper validates robustly a number of sfm mvs surveys against total station and extensive tls data at three nested scales plots 30 m2 within a small catchment 4710 m2 within an eroding marl badland landscape 1 km2 sfm surveys from a number of platforms are evaluated based on i topography ii sub grid roughness and iii change detection capabilities at an annual scale oblique ground based images can provide a high quality surface equivalent to tls at the plot scale but become unreliable over larger areas of complex terrain degradation of surface quality with range is observed clearly for sfm models derived from aerial imagery recently modelled doming effects from the use of vertical imagery are proven empirically as a piloted gyrocopter survey at 50m altitude with convergent off nadir imagery provided higher quality data than an unmanned aerial vehicle uav flying at the same height and collecting vertical imagery for soil erosion monitoring sfm can provide data comparable with tls only from small survey ranges 5 m and is best limited to survey ranges 10 20 m synthesis of these results with existing validation studies shows a clear degradation of root mean squared error rmse with survey range with a median ratio between rmse and survey range of 1 639 and highlights the effect of the validation method e g point cloud or raster based on the estimated quality

bathymetric structure from motion extracting shallow stream bathymetry from multi view stereo photogrammetry stream bathymetry is a critical variable in a number of river science applications in larger rivers bathymetry can be measured with instruments such as sonar single or multi beam bathymetric airborne lidar light detection and ranging or acoustic doppler current profilers however in smaller streams with depths less than 2 m bathymetry is one of the more difficult variables to map at high resolution optical remote sensing techniques offer several potential solutions for collecting high resolution bathymetry in this research i focus on direct photogrammetric measurements of bathymetry using multi view stereo photogrammetry specifically structure from motion sfm the main barrier to accurate bathymetric mapping with any photogrammetric technique is correcting for the refraction of light as it passes between the two different media air and water which causes water depths to appear shallower than they are i propose and test an iterative approach that calculates a series of refraction correction equations for every point camera combination in a sfm point cloud this new method is meant to address shortcomings of other correction techniques and works within the current preferred method for sfm data collection oblique and highly convergent photographs the multi camera refraction correction presented here produces bathymetric datasets with accuracies of 0 02 of the flying height and precisions of 0 1 of the flying height this methodology like many fluvial remote sensing methods will only work under ideal conditions e g clear water but it provides an additional tool for collecting high resolution bathymetric datasets for a variety of river coastal and estuary systems copyright 2016 john wiley sons ltd

guidelines on the use of structure from motion photogrammetry in geomorphic research as a topographic modelling technique structure from motion sfm photogrammetry combines the utility of digital photogrammetry with a flexibility and ease of use derived from multi view computer vision methods in conjunction with the rapidly increasing availability of imagery particularly from unmanned aerial vehicles sfm photogrammetry represents a powerful tool for geomorphological research however to fully realize this potential its application must be carefully underpinned by photogrammetric considerations surveys should be reported in sufficient detail to be repeatable if practical and results appropriately assessed to understand fully the potential errors involved to deliver these goals robust survey and reporting must be supported through i using appropriate survey design ii applying suitable statistics to identify systematic error bias and to estimate precision within results and iii propagating uncertainty estimates into the final data products

slip along the san andreas fault associated with the great 1857 earthquake historical records indicate that several meters of lateral slip along the san andreas fault accompanied the great 1857 earthquake in central and southern california these records together with dendrochronological evidence suggest that the rupture occurred along 360 to 400 km of the fault including several tens of kilometers of the currently creeping reach in central california geomorphic expressions of late holocene right lateral offsets are abundant along the 1857 rupture along 300 kilometers of the 1857 rupture between cholame and wrightwood the youngest discernible offset ranges from 3 to 9 1 2 meters dormancy of the fault since 1857 almost certainly indicates that this latest offset was created in 1857 fault slip apparently associated with the 1857 earthquake varies in a broadly systematic way along the trace of the fault it is relatively uniform along each of several long segments but changes rather abruptly in value between these segments this nonuniform displacement pattern may imply that some segments of the fault rupture more frequently or experience a slower long term slip rate than others the 1857 offsets indicate a seismic moment m o between 5 3 and 8 7 10 27 dyne cm assuming a 10 to 15 km depth of rupture and relatively uniform slip as a function of depth a comparison with the rupture length average slip value and tectonic setting of the california earthquake of 1906 m s 8 1 4 indicates a value of m 8 1 4 for the 1857 event

field application of close range digital photogrammetry crdp for grain scale fluvial morphology studies in situ measurement of grain scale fluvial morphology is important for studies on grain roughness sediment transport and the interactions between animals and the geomorphology topics relevant to many river practitioners close range digital photogrammetry crdp and terrestrial laser scanning tls are the two most common techniques to obtain high resolution digital elevation models dems from fluvial surfaces however field application of topography remote sensing at the grain scale is presently hindered mainly by the tedious workflow challenges that one needs to overcome to obtain high accuracy elevation data a recommended approach for crdp to collect high resolution and high accuracy dems has been developed for gravel bed flume studies the present paper investigates the deployment of the laboratory technique on three exposed gravel bars in a natural river environment in contrast to other approaches having the calibration carried out in the laboratory removes the need for independently surveyed ground control targets and makes for an efficient and effective data collection in the field optimization of the gravel bed imagery helps dem collection without being impacted by variable lighting conditions the benefit of a light weight three dimensional printed gravel bed model for dem quality assessment is shown and confirms the reliability of grain roughness data measured with crdp imagery and dem analysis evidences sedimentological contrasts between gravel bars within the reach the analysis of the surface elevations shows the effect variable grain size and sediment sorting have on the surface roughness by plotting the two dimensional structure functions and surface slopes and aspects we identify different grain arrangements and surface structures the calculation of the inclination index allows determining the surface forming flow direction s we show that progress in topography remote sensing is important to extend our knowledge on fluvial morphology processes at the grain scale and how a technique customized for use by fluvial geomorphologists in the field benefits this progress copyright 2016 john wiley sons ltd

faulting associated with large earthquakes and the average rate of deformation in central and eastern asia we determine approximate average rates of deformation in portions of eastern and central asia for the last 80 years these rates are based on estimates of source dimensions average displacements seismic moments and orientations of faults of all large earthquakes m 7 5 and as many other major earthquakes m 7 0 as possible in asia since 1900 a major part of this study is the compilation of these data for separate parts of asia we combine seismic moment tensors to estimate the average rotational strain or deformation tensors for these regions for the last 80 years we estimate that shortening across the tien shan has occurred at 11 mm yr between 5 and 19 mm yr left lateral shear on easterly trending planes in mongolia in northwestern tibet gansu and ningxia and on the xianshuihe fault in western sichuan has been very rapid more than 10 mm yr in each region and apparently as rapid as 40 mm yr in northwestern tibet gansu and ningxia slower rates of a few to 10 mm yr appear to characterize east west extension and conjugate north south shortening of tibet the earthquake history of the himalaya is consistent with rates of underthrusting of more than 10 mm yr but is probably less than the convergence rate of india with eurasia of about 50 mm yr the overall strain field is consistent with a large part of india s penetration into eurasia being absorbed by the extrusion of material out of india s way as a result southeast china moved at about 21 mm yr east southeast with respect to eurasia in the last 80 years with an uncertainty of about a factor of 2 in this estimated rate

structure from motion photogrammetry a low cost effective tool for geoscience applications abstract high resolution topographic surveying is traditionally associated with high capital and logistical costs so that data acquisition is often passed on to specialist third party organisations the high costs of data collection are for many applications in the earth sciences exacerbated by the remoteness and inaccessibility of many field sites rendering cheaper more portable surveying platforms i e terrestrial laser scanning or gps impractical this paper outlines a revolutionary low cost user friendly photogrammetric technique for obtaining high resolution datasets at a range of scales termed structure from motion sfm traditional softcopy photogrammetric methods require the 3 d location and pose of the camera s or the 3 d location of ground control points to be known to facilitate scene triangulation and reconstruction in contrast the sfm method solves the camera pose and scene geometry simultaneously and automatically using a highly redundant bundle adjustment based on matching features in multiple overlapping offset images a comprehensive introduction to the technique is presented followed by an outline of the methods used to create high resolution digital elevation models dems from extensive photosets obtained using a consumer grade digital camera as an initial appraisal of the technique an sfm derived dem is compared directly with a similar model obtained using terrestrial laser scanning this intercomparison reveals that decimetre scale vertical accuracy can be achieved using sfm even for sites with complex topography and a range of land covers example applications of sfm are presented for three contrasting landforms across a range of scales including an exposed rocky coastal cliff a breached moraine dam complex and a glacially sculpted bedrock ridge the sfm technique represents a major advancement in the field of photogrammetry for geoscience applications our results and experiences indicate sfm is an inexpensive effective and flexible approach to capturing complex topography

straightforward reconstruction of 3d surfaces and topography with a camera accuracy and geoscience application topographic measurements for detailed studies of processes such as erosion or mass movement are usually acquired by expensive laser scanners or rigorous photogrammetry here we test and use an alternative technique based on freely available computer vision software which allows general geoscientists to easily create accurate 3d models from field photographs taken with a consumer grade camera the approach integrates structure from motion sfm and multi view stereo mvs algorithms and in contrast to traditional photogrammetry techniques it requires little expertise and few control measurements and processing is automated to assess the precision of the results we compare sfm mvs models spanning spatial scales of centimeters a hand sample to kilometers the summit craters of piton de la fournaise volcano with data acquired from laser scanning and formal close range photogrammetry the relative precision ratio achieved by sfm mvs measurement precision observation distance is limited by the straightforward camera calibration model used in the software but generally exceeds 1 1000 i e centimeter level precision over measurement distances of 10s of meters we apply sfm mvs at an intermediate scale to determine erosion rates along a 50 m long coastal cliff seven surveys carried out over a year indicate an average retreat rate of 0 70 0 05 m a 1 sequential erosion maps at 0 05 m grid resolution highlight the spatio temporal variability in the retreat with semivariogram analysis indicating a correlation between volume loss and length scale compared with a laser scanner survey of the same site sfm mvs produced comparable data and reduced data collection time by 80

western irian jaya the end product of oblique plate convergence in the late tertiary abstract the island of new guinea is the surface expression of the deformed northern margin of the australian continental block to the south undeformed continental crust is overlain by flat lying platform sediments that form a conformable sequence from late palaeozoic to late tertiary along the new guinea cordillera these platform sediments have been tightly folded and overthrust to the south as a result of crustal shortening caused by convergence between the australian plate and the pacific plate the earth movements resulting from this convergence started at the end of the miocene and continue to the present day it is postulated that all the major structures of western irian jaya were caused by this orogeny and can be explained by the convergence directed southwest northeast between the australian and pacific plates it is further postulated that the convergence has remained essentially constant since the start of the earth movements this convergence is consistent with that postulated in the circum pacific plate tectonic map aapg 1981 of 12 5 cm yr directed about 15 south of west only if the effects of the sorong yapen fault system are taken into account this complex east west trending fault system forms the southern boundary of the pacific plate and has responded to the convergence by left lateral strike slip displacement of at least 370 km since the late miocene as a consequence south of the sorong yapen fault system the convergence has been directed more to the south i e at least 45 south of west in this region south of the fault zones the north south component of the convergence has been accommodated in the east by folding and overthrusting over a wide zone of interaction called the new guinea mobile belt dow 1977 in the west on the other hand the australian continental crust has been a stable buttress kepala burung fig 2 which following convergence has protruded into the pacific plate its northeastern margin has therefore been exposed to the full brunt of collision with the pacific plate and large segments of continental crust have been broken off and rafted westwards in order to accommodate the difference in crustal shortening between the new guinea mobile belt and kepala burung two fundamental crustal fractures formed in the intervening region the waipoga and wandamen faults these fractures make angles of about 65 with the regional structural trend fig 2 and they were the focus of most of the resulting differential crustal displacement two of the more spectacular examples of this differential movement have been the thrusting of large slabs of crustal rocks tens of kilometres southwards over the australian continental crust weyland overthrust and lengguru fold belt

controls on large boulder mobility in an auto naturalized constructed step pool river san clemente reroute and dam removal project carmel river california usa

three dimensional dense distributed temperature sensing for measuring layered thermohaline systems distributed temperature sensing has proven a useful technique for geoscientists to obtain spatially distributed temperature data when studies require high resolution temperature data in three spatial dimensions current practices to enhance the spatial resolution do not suffice for example double diffusive phenomena induce sharp and small scale temperature patterns in water bodies subject to thermohaline gradients this article presents a novel approach for a 3 d dense distributed temperature sensing setup the design of which can be customized to the required spatial resolution in each dimension temperature is measured along fiber optic cables that can be arranged as needed in this case we built a dense cage of very thin 1 6 mm cables to ensure that interference with flow patterns was minimal application in water bodies with double diffusion induced sharp temperature gradients shows that the setup is well able to capture small scale temperature patterns and even detects small unsuspected seeps and potential salt fingers however the potential effect of the setup on the flow patterns requires further study

on the evolution of marginal basins this paper presents a critique of the models proposed to explain the formation of back arc basins those marginal basins located behind active or inactive trench systems and whose origin is inferred to be subduction related several marginal basins are not generically back arc but rather are related to the initiation of subduction continental rifting or plate boundary readjustments models of back arc basin formation must be consistent with the observed characteristics of back arc basins which include the following 1 the crustal structure and magnetic lineation patterns of back arc and major ocean basins are similar implying that the processes of crustal accretion in both tectonic environments are also similar 2 arc trench systems without currently spreading back arc basins are in the majority 3 although petrographically similar to and within the compositional range of midocean ridge basalts morb back arc basin basalts babb show consistent geochemical differences from n type morb and are in many respects transitional toward island arc tholeiites iat 4 distinct babb and iat mantle sources may be in extremely close proximity during the initial rifting of an island arc 5 rifting of the volcanic arc may occur on either side of the line of active volcanoes 50 km and may vary from one side to the other along strike 6 a remnant arc is not always developed 7 back arc spreading may be initiated above subducted lithosphere but with time the center of spreading migrates away from the arc and no longer overlies a benioff zone and 8 there is no simple correlation between the timing of global plate reorganizations and the formation of back arc basins the three main classes of models proposed to explain back arc basin formation are mantle diapirism induced aesthenospheric convection and global plate kinematics because the driving mechanism for the first two classes of models is provided by the local subducting slab these models fail to explain the temporal and spatial distribution of back arc basins the third class of models proposes that back arc basins should form whenever global plate interactions require divergence between the overriding plate and the trench line the latter being observed to move only in a seaward direction with respect to a hot spot reference frame however the tectonic setting of several back arc basins suggests that they represent more than just a passive response to kinematic boundary conditions for example some dynamic back arc force seems required to move the new hebrides tonga and south sandwich forearc plates seaward neither the local nor the global models adequately specify the necessary and or sufficient conditions for back arc basin formation a better understanding of the processes associated with the initiation of rifting and of subduction is required arc rifting and back arc spreading are both secondary phenomena to subduction but they are also primary extensional phenomena fundamentally analogous to continental rifting and the initial spreading of major ocean basins

seismic strain rates in regions of distributed continental deformation we compare the rates and configurations of seismic deformation determined from moment tensor mechanisms of earthquakes in five continental regions with the rates and configurations expected if the seismicity reflected the relative plate motions in the regions the five regions the aegean iran california western new guinea and central asia are characterized by high levels of seismicity distributed over hundreds to thousands of kilometers from the accepted plate boundaries the earthquake mechanisms are compiled primarily from the catalog of centroid moment tensor solutions which is nearly complete over the interval 1977 1987 for earthquakes greater than ms 5 the thickness of the seismogenic layer in each region is constrained by the results of modeling broadband body wave phases and of previous earthquake studies in the aegean california and western new guinea the observed configurations of deformation agree with a simple model of distributed accommodation of relative plate motion in iran and central asia the moment tensors indicate that there is appreciable strain parallel to the strikes of the belts we augment our 10 year estimates of seismic deformation with the available historical moment and magnitude estimates for the five regions and find that moderate and large earthquakes account for between 25 and 70 of the deformation of the seismogenic layer