removal of systematic seasonal atmospheric signal from interferometric synthetic aperture radar ground deformation time series applying the multidimensional small baseline subset interferometric synthetic aperture radar algorithm to about 1500 envisat and radarsat 2 interferograms spanning 2003 2013 we computed time series of ground deformation over naples bay area in italy two active volcanoes vesuvius and campi flegrei are located in this area in close proximity to the densely populated city of naples for the first time and with remarkable clarity we observed decade long elevation dependent seasonal oscillations of the vertical displacement component with a peak to peak amplitude of up to 3 0 cm substantially larger than the long term deformation rate 0 6 cm yr analysis utilizing surface weather and radiosonde data linked observed oscillations with seasonal fluctuations of water vapor air pressure and temperature in the lower troposphere the modeled correction is in a good agreement with observed results the mean absolute and rms differences are 0 014 cm 0 073 cm and 0 087 cm respectively atmospherically corrected time series confirmed continuing subsidence at vesuvius previously observed by geodetic techniques

surface textures of heavy mineral grains a new contribution to provenance studies abstract the study zone is geologically very complex and corresponds to the western limits of the betic cordilleras sw spain materials from the triassic to holocene are found here this study demonstrates that most of the surface textures seen on quartz are present on the seven selected heavy minerals sem analysis of heavy mineral grains reveals that certain morphologies are in part associated with particular surface textures this textural analysis enables the source areas to be differentiated more clearly equally it contributes to a deeper knowledge of the various stages of the grains provenance a good example is the study of the heavy minerals of the guadalete river terraces

heavy mineral compositions of the changjiang yangtze river sediments and their provenance tracing implication abstract a total of 71 floodplain sediments were collected from the mainstream and major tributaries of the changjiang for heavy mineral examinations the upper changjiang samples contain more heavy minerals in the very fine sand fraction than the middle lower samples which are relatively enriched in polygenetic heavy minerals the heavy mineral assemblages are characterized by fe ti oxide minerals calcic amphibole epidote garnet biotite and zircon which exhibit large variations in percent between different tributaries and the mainstream the widely distributed granitoids and permian emeishan basalt in the drainage basins account for the high contents of zircon and hypersthene in the xiangjiang and daduhe samples respectively most of the detrital magnetite grains are homogeneous in typomorphic feature and almost stoichiometric in chemical composition the discrimination plot of tio2 v2o3 versus mgo mgo al2o3 suggests that most of the detrital magnetite grains are sourced from felsic plutonic volcanic and metamorphic parent rocks and those from different tributaries have distinct chemical compositions our study suggests that the combination of transparent heavy mineral assemblages and varietal study of individual heavy minerals sheds new light on the provenance discrimination of the changjiang sediments and contributes to the mineralogical determination of ancient source rocks within a large drainage basin despite the sediment recycling and complex source rock types

rivers and loess the significance of long river transportation in the complex event sequence approach to loess deposit formation abstract rivers are essential for loess deposit formation river systems which relate directly to loess deposit formation include the danube and the rhine the mississippi and the missouri the thames and the medway the indus ganges and brahmaputra the dnepr don and volga the clutha mataura and rakaia new zealand rivers the yellow river rivers in south america siberian rivers flowing north the odra and the wisla between the mountains and the ice the syr darya and amu darya into the desert the contention is that rivers are not just important in major loess deposit formation they are mandatory necessary imperative obligatory essential indispensable requisite for a complete and satisfactory study of a loess deposit we need to know how the material is produced how it is transported and distributed across the landscape how intermediate deposits are formed how transportation provides the defining properties i e open structure collapsibility draping across the landscape and what may happen post deposition e g chernozemisation fragipan formation increased collapsibility etc if rivers are essential then it would appear that the british loess is probably alpine material delivered by the proto rhine and the polish loess is not derived from the ice sheet to the north but from the mountains to the south the lack of loess in canada is explained by the absence of suitable rivers the loess in russia and neighbouring countries can be classified as jefferson et al jefferson i f evstatiev d karastenev d mavlyanova n g smalley i j 2003b the engineering geology of loess and loess like deposits a commentary on the russian literature engineering geology 68 333 351 suggested on the basis of associated rivers a new deposit of glacial loess is recognised associated with the dnepr don and volga rivers the uswr loess the smalley leach smalley i j leach j a 1978 the origin and distribution of the loess in the danube basin and associated regions of east central europe a review sedimentary geology 21 1 26 available from www geo edu ro sgr mod downloads pdf smalley sedgeo 1978 pdf vision of the loess in the danube basin and east central europe is probably misconceived they assigned a great significance to glacial action and put loess in a northern band it appears that this proposed glacial influence is minimal and that the danube loess is essentially mountain loess derived from the alps the carpathians the sudeten mountains and other high regions the danube system is a classic example of a river controlling loess distribution

detecting and monitoring of landslides using persistent scattering synthetic aperture radar interferometry persistent scatterer synthetic aperture radar interferometry psinsar is an applied time series technique to overcome limitations of insar temporal and geometrical decorrelation and atmospheric delay anomalies for monitoring of ground surface deformations this method only monitors displacements on pixels with nearly constant temporal backscattering characteristics in this study datasets of ascending alos palsar l band images recorded from 2006 to 2010 and descending envisat asar c band images acquisitioned between 2003 and 2010 were processed to detect and monitor the landslide occurred in the noghol area iran application of the psinsar technique on both palsar and asar images has significantly improved monitoring of the noghol landslide however the determination of vertical displacement of the landslide by the asar images processing is more correct compared to results of the palsar processing due to the descending orbital motion of asar the asar images also overwhelm palsar images for determination of the landslide extent because of detection of more persistent scatterer points the landslide displacement and aspect obtained by the global navigation satellite system gnss and psinsar techniques are in agreement about 1 2 1 5 m westward in the period of 2003 2010 particularly processing results of the asar images are more similar to the gnss measurements furthermore assessment of the landslide type mechanism and its displacement direction were possible by integration of the palsar and asar radar images with ascending and descending orbital motions respectively

mineralogy of the ganges and brahmaputra rivers implications for river switching and late quaternary climate change late quaternary sediments of the bengal basin contain a history of river switching and climate change as revealed from sand and clay size mineralogy of boreholes and modern riverbed grabs epidote to garnet ratios e g in sand fraction sediments are diagnostic of source with high 1 e g indicating brahmaputra provenance and low 1 e g indicating ganges provenance in the clay fraction of surficial sediments smectite is diagnostic with high values 39 in the ganges and low values 3 in the brahmaputra in contrast the brahmaputra contains more kaolinite 29 vs 18 more illite 63 vs 41 and more chlorite 3 vs 1 than the ganges analysis of mineralogic and stratigraphic data indicates that the two rivers have changed position several times during the holocene extended periods of mixed river inputs appear to be isolated to the early holocene suggesting rapidly migrating braided channels during sea level lowstand tectonically driven accommodation in the sylhet basin may have contributed to the favored easterly course of the brahmaputra during much of the holocene relative abundances of illite and chlorite ic vs smectite and kaolinite sk record varying degrees of physical and chemical weathering respectively high ic values in early post glacial deposits suggest a dominance of physical weathering at that time however a general increase in sk concentrations throughout the holocene appears to reflect enhanced chemical weathering under increasingly warmer and more humid conditions notably a peak in sk concentrations that corresponds to an early holocene warm period 10 7 ka suggests that weathering patterns in the catchment respond quickly to climatic shifts

a detrital heavy mineral viewpoint on sediment provenance and tropical weathering in se asia abstract understanding heavy mineral preservation is important for interpreting generation pathways provenance and geochemistry of sediments despite this many assumptions about heavy mineral stability are based on ancient strata and few studies consider modern sediments particularly those in tectonically active tropical areas such as se asia we report new heavy mineral data on 69 river sand samples from the malay peninsula and sumatra in which one aim was to find provenance indicators specific to these areas identifications were performed using optical microscopy and confirmed with sem eds in the malay peninsula heavy minerals record granitic and contact metamorphic provenance variable amounts of zircon tourmaline hornblende andalusite epidote monazite rutile and titanite and minor amounts of pyroxene apatite anatase garnet diaspore colourless spinel cassiterite and allanite are typical of this source area the composition of assemblages from sumatra indicates contributions from two major sources the modern volcanic arc i and the basement ii abundant pyroxene particularly hypersthene up to 70 is diagnostic of the volcanic arc source vesuvianite garnet andalusite tourmaline chrome spinel rutile anatase and corundum are present only in small amounts

recent advances in sar interferometry time series analysis for measuring crustal deformation abstract synthetic aperture radar sar interferometry is a technique that permits remote detection of deformation at the earth s surface and has been used extensively to measure displacements associated with earthquakes volcanic activity and many other crustal deformation phenomena analysis of a time series of sar images extends the area where interferometry can be successfully applied and also allows detection of smaller displacements through the reduction of error sources here we review recent advances in time series sar interferometry methods that further improve accuracy this is particularly important when constraining displacements due to processes with low strain rates such as interseismic deformation we include examples of improved algorithms applied to image deformation associated with the 2010 eruption of eyjafjallajokull volcano in iceland slow slip on the guerrero subduction zone in mexico and tectonic deformation in western anatolia turkey

detection of a locked zone at depth on the parkfield california segment of the san andreas fault the parkfield california segment of the san andreas fault is transitional in character between the creeping segment of the fault to the northwest and the locked carrizo plain segment to the southeast the rate of shallow fault slip decreases from 25 30 mm yr northwest of the epicenter of the 1966 parkfield earthquake to zero at the southeastern end of the 1966 rupture zone data from a network of trilateration lines spanning the san andreas fault near parkfield and extending to the pacific coast near san luis obispo shed light on the rate of fault slip at depth since the 1966 earthquake in this study average rates of line length change and shallow fault slip were inverted to determine the slip rate at depth on the parkfield fault segment the fault is taken to be a vertical surface with unknown distribution of strike slip displacement in an elastic half space a striking result of the inversions is that all solutions providing acceptable fits to the data exhibit a locked zone essentially coincident with the rupture surface of the 1966 parkfield earthquake the data require that the locked zone extend nearly as far north as the 1966 epicenter however the vertical extent of the locked zone is not well resolved over much of the parkfield segment the fault is slipping faster at the earth s surface than it is at seismogenic depths in order to fit the trilateration measurements it is necessary to include a component of contraction normal to the trend of the san andreas the inversion results suggest a spatially uniform normal strain of 0 06 strain yr the orientation of the contraction is compatible with geologic and seismic evidence of active folding and reverse faulting in the region the magnitude of the contraction is consistent with convergence rates inferred from global plate motion models

source parameters for the 1952 kern county earthquake california a joint inversion of leveling and triangulation observations coseismic leveling and triangulation observations are used to determine the faulting geometry and slip distribution of the july 21 1952 mw 7 3 kern county earthquake on the white wolf fault a singular value decomposition inversion is used to assess the ability of the geodetic network to resolve slip along a multisegment fault and shows that the network is sufficient to resolve slip along the surface rupture to a depth of 10 km below 10 km the network can only resolve dip slip near the fault ends the preferred source model is a two segment right stepping fault with a strike of 51 and a dip of 75 sw the epicentral patch has deep 6 27 km left lateral oblique slip while the northeastern patch has shallow 1 12 5 km reverse slip there is nearly uniform reverse slip epicentral 1 6 m northeast 1 9 m with 3 6 m of left lateral strike slip limited to the epicentral patch the seismic moment is m0 9 2 0 5 1019 n m mw 7 2 the signal to noise ratio of the leveling and triangulation data is reduced by 96 and 49 respectively the slip distribution from the preferred model matches regional geomorphic features and may provide a driving mechanism for regional shortening across the comanche thrust and structural continuity with the scodie seismic lineament to the northeast

world wide delivery of river sediment to the oceans new data and new estimates from old data show that rivers with large sediment loads annual discharges greater than about 15 times 10 6 tons contribute about 7 times 10 9 tons of suspended sediment to the ocean yearly extrapolating available data for all drainage basins the total suspended sediment delivered by all rivers to the oceans is about 13 5 times 10 9 tons annually bedload and flood discharges may account for an additional 1 2 times 10 9 tons about 70 of this total is derived from southern asia and the larger islands in the pacific and indian oceans where sediment yields are much greater than for other drainage basins

the effect of the coarse aeolian sand on siltation of the inner mongolian reach of the yellow river the yellow river flows through an extensive aeolian inner mongolian plateau with a total length of 673 km owing to the high erodibility of the wulanbuhe and kubuqi deserts and the impacts of its upstream reservoirs the siltation of the inner mongolian reach of the yellow river is caused essentially by the aeolian particles larger than 0 1 mm which are very different from the sediment 0 05 mm of the lower yellow river coming from the loess plateau during the period 1954 2000 the total accumulated sediment of this area was about 20 1 108 t the coarse sediment larger than 0 1 mm as about 15 2 108 t and the fine sediment less than 0 1 mm fs about 4 9 108 t in particular there was 6 1 108 t as coming from the wulanbuhe desert and 5 82 108 t as from the kubuqi desert deposited in the river channel of the inner mongolian reach representing 78 6 of the total coarse sediment larger than 0 1 mm

synthetic heavy mineral stratigraphy applications and limitations abstract a multi disciplinary study of the dominantly fluvial lower triassic otter sandstone formation east devon uk is presented the approach integrates a variety of methods including sedimentology conventional heavy mineral analysis single grain microprobe analysis and elemental whole rock geochemistry icp aes and icp ms a species level conventional heavy mineral study is compared to a whole rock geochemical analysis for the corresponding samples to investigate whether or not heavy mineral compositions can be discriminated from elemental whole rock data the comparison provides sufficient evidence that the absolute and relative abundance of some of the heavy minerals apatite iron titanium oxides monazite and zircon can be discriminated geochemically the established element mineral relationships are used to construct both synthetic heavy mineral assemblages and synthetic heavy mineral index values from the geochemical data which show considerable similarity to those of the conventional heavy mineral analysis the presented synthetic heavy mineral logs display intraformational packages that enable subdivision of this barren continental succession furthermore the observed subdivision is correlatable over a considerable distance when extended into the offshore wessex basin the chemical approach unquestionably lacks the sensitivity of conventional heavy mineral analysis however by comparison it is rapid this novel approach demonstrates that synthetic heavy mineral stratigraphy based as here on a well constrained stratotype has considerable potential for creating high resolution correlations in both outcrops and the subsurface and may be of significant value to people working with reservoir characterisation

pre and post failure spatial temporal deformation pattern of the baige landslide retrieved from multiple radar and optical satellite images abstract the baige landslide in southwest china has been active for at least 50 years and experienced two failure events on oct 10 and nov 3 2018 the rock mass and debris of the slope failure formed a landslide dam the discharge of the dammed lake plus the failure events caused significant socio economic losses many slow moving areas appeared after the two failure events and potential landslide risk still exists retrieving the long term spatial temporal pattern of landslide activity can help us to understand and mitigate landslide disasters however it is difficult to monitor all movement episodes of some landslides using single satellite dataset and method due to the different deformation characteristics employing multiple radar and optical images may solve this problem in this study the landsat 8 the alos palsar and alos 2 palsar 2 images are used to obtain the surface displacements before the first failure event by using the cross correlation technique for landsat 8 images and the pixel offset tracking technique the displacement velocity map after the second failure is derived by the multi temporal synthetic aperture radar interferometry mt insar method from the alos 2 palsar 2 and the sentinel 1 images the maximum radar line of sight los average velocity is 3 m yr between jan 2007 and feb 2011 and 12 m yr between jul 2015 and jul 2018 from oct 2013 to feb 2018 the maximum horizontal average velocity is 5 8 m yr the movement accelerated from jul 2017 a large deformation area appeared on the south of the failed slope after the second failure the unstable area observed by the mt insar is much larger than that obtained through the field measurements in the first month after the second failure the maximum los displacements are more than 20 cm the depletion area and the neighboring zones of the landslide are unstable even one year after the second failure this study shows how to use multiple satellite images and hybrid remote sensing techniques to investigate the landslide deformation history and illustrates the benefits of landslide monitoring based on images from multiple satellite sensors

the provenance of taklamakan desert sand sand migration in the vast taklamakan desert within the tarim basin xinjiang uyghur autonomous region pr china is governed by two competing transport agents wind and water which work in diametrically opposed directions net aeolian transport is from northeast to south while fluvial transport occurs from the south to the north and then west to east at the northern rim due to a gradual northward slope of the underlying topography we here present the first comprehensive provenance study of taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea and to consider the potential of the tarim basin as a contributing source to the chinese loess plateau clp our dataset comprises 39 aeolian and fluvial samples which were characterised by detrital zircon u pb geochronology heavy mineral and bulk petrography analyses although the inter sample differences of all three datasets are subtle a multivariate statistical analysis using multidimensional scaling mds clearly shows that tarim desert sand is most similar in composition to rivers draining the kunlun shan south and the pamirs west and is distinctly different from sediment sources in the tian shan north a small set of samples from the junggar basin north of the tian shan yields different detrital compositions and age spectra than anywhere in the tarim basin indicating that aeolian sediment exchange between the two basins is minimal although river transport dominates delivery of sand into the tarim basin wind remobilises and reworks the sediment in the central sand sea characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the tarim river and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea smaller ephemeral rivers from the kunlun shan end in the desert and discharge their sediment there both river run off and wind intensity are strongly seasonal their respective transport strength and opposing directions maintain the taklamakan in its position and topography

clay mineral fluctuations and surface textural analysis of quartz grains in pliocene quaternary marine sediments from wilkes land continental rise east antarctica paleoenvironmental significance abstract pliocene quaternary marine sediments from wilkes land continental rise were investigated using clay mineral analysis and quartz grain surface texture observations the studied piston cores were collected during a geophysical and geological survey in the framework of the italian and australian wega project the cores were collected along two transects crossing the channel mound system that characterizes the wilkes land continental rise massive and laminated facies were recognized in these sedimentary sequences the clay mineral assemblages are dominated by illite smectite and chlorite occur in intermediate amounts whereas kaolinite is scarce illite derives from the hinterland of the mertz and ninnis glaciers smectite and kaolinite derive from the ross sea area and they are transported by westward marine bottom currents chlorite is derived both from the adjacent continent and from the victoria land different concentrations of individual clay minerals in the massive and laminated facies are controlled by the interplay between different source areas and the main sedimentary processes glacial and eolian quartz grains prevail in the massive units indicating short transportation and rapid deposition from melting ices with no further significant transport action by marine currents in the laminated facies the high amount of quartz grains affected by high energy subaqueous transport features are related both to turbiditic processes and to bottom current transport

permanent scatterers for landslide investigations outcomes from the esa slam project within the slam project service for landslide monitoring launched in 2003 by the european space agency esa the permanent scatterers ps technique a multi image interferometric approach coupled with the interpretation of aerial photos and optical satellite images was carried out for landslide investigations the ps analysis was applied at a regional scale as support for landslide inventory mapping and at local scale for the monitoring of single well known slope movements for the integration of the ps measurements within a landslide inventory the arno river basin italy was chosen as test site for the presence of a high number of mass movements to date about 300 areas at high landslide risk and more than 27 000 individual landslides mapped by the institutional authorities about 350 sar images have been interferometrically processed by means of the ps technique with the detection of about 600 000 ps the use of optical images contributed spatial meaning to the point wise information provided by the ps making it easier to identify terrain features related to slope instability and the landslide boundaries here we describe the employed methodology and its impact in the updating of a preexisting landslide inventory 6 8 of the total number of landslides were characterized by ground displacement measurements from the ps 6 1 of already mapped landslides and 0 8 of new unstable areas detected through the ps analysis moreover most of the ps are located in urban areas showing that the proposed methodology is suitable for landslide mapping in areas with a quite high density of urbanization but that over vegetated areas it still suffers from the limitations induced by the current space borne sar missions e g temporal de correlation on the other hand the use of insar for the monitoring of single slow landslides threatening built up areas has provided satisfactory results allowing the measurement of superficial deformations with high accuracy on the landslide sectors characterized by a good radar reflectivity and coherence

long term morphodynamic changes of a desert reach of the yellow river following upstream large reservoirs operation abstract china s yellow river has experienced its dramatically decreasing trend for the flow discharge since the construction and operation of large reservoirs located upstream this low flow regulation has triggered a severe aggradation of the ulan buh desert channel of the yellow river because the declining flow exhibits no capability to scour and carry away large amount input of desert sands from the ulan buh desert twenty monitoring cross sections documented the ulan buh desert channel has experienced its increasing aggradational trend in conjunction with its lateral migration decreasing trend from 1966 to 2005 which is opposite to the normal pattern of aggradation with deepening or symmetrical infilling for a channel located downstream of a reservoir the channel aggradation can also be identified two stages slow aggradation and rapid aggradation slow aggradation is characterized by the channel bed elevation rising 9 5 cm on average between 1968 and 1985 which responded to the operation of the liujiaxia reservoir during this period the flow discharge was similar to pre dam flow conditions but the sediment transport reduced to half of its pre dam value because of about 0 24 108 t of desert sands entering the channel from the ulan buh desert annually this dilute flow indicated not to scour the channel as expected but contrarily to cause the channel aggraded rapid aggradation followed completion of the longyangxia reservoir with the channel bed elevation rising by 73 cm on average between 1986 and 2005 in this period the combined regulation of liujiaxia and longyangxia reservoirs has caused the flow discharge decreasing dramatically which is more beneficial for accumulation of the desert sands 0 19 108 t yr 1 on average in the desert channel and led to the channel aggradation rate accelerated rapidly

ground deformation monitoring by using the permanent scatterers technique the example of the oltrepo pavese lombardia italy abstract the applicability of the permanent scatterers synthetic aperture radar interferometry psinsar technique for detecting and monitoring ground displacements was tested in the oltrepo pavese territory northern italy southern lombardia which could be representative of similar geological contexts in the italian apennines the study area which extends for almost 1100 km 2 is characterized by a complex geological and structural setting and the presence of clay rich sedimentary formations these characteristics make the oltrepo pavese particularly prone to several geological hazards shallow and deep landslides subsidence and swelling shrinkage of the clayey soils the psinsar technique used in this study overcomes most of the limitations of conventional interferometric approaches by identifying within the area of interest a set of radar benchmarks ps where very precise displacement measurements can be carried out more than 90 000 ps were identified by processing synthetic aperture radar sar images acquired from 1992 to 2001 by the european remote sensing satellites ers the psinsar application at a sub regional scale detected slow ground deformations ranging from 5 to 16 mm year and resulting from various processes landslides swelling shrinkage of clay soils and water pumping the ps displacements were analysed by collecting data obtained through geological geomorphologic field surveys geotechnical analysis of the soils and the information was integrated within a landslide inventory and the damaged building inventory despite the limited number of landslide bodies with ps 7 of the inventoried landslides the ps data helped to revise the state of activity of several landslides furthermore some previously unknown unstable slopes were detected two areas of uplift and two areas of subsidence were identified

crustal strain near the big bend of the san andreas fault analysis of the los padres tehachapi trilateration networks california in the region of the los padres tehachapi geodetic network the san andreas fault saf changes its orientation by over 30 degree from n 40 degree w close to that predicted by plate motion for a transform boundary to n 73 degree w the strain orientation near the saf is consistent with right lateral shear along the fault with maximum shear rate of 0 38 plus minus 0 01 mu rad yr at n 63 degree w in contrast away from the saf the strain orientations on both sides of the fault are consistent with the plate motion direction with maximum shear rate of 0 19 plus minus 0 01 mu rad yr at n 44 degree w the strain rate does not drop off rapidly away from the fault and thus the area is fit by either a broad shear zone below the saf or a single fault with a relatively deep locking depth the fit to the line length data is poor for locking depth d less than 25 km for d of 25 km a buried slip rate of 30 plus minus 6 mm yr is estimated the authors also estimated buried slip for models that include the garlock and big pine faults in addition to the saf slip rates on other faults are poorly constrained bymore the los padres tehachapi network the best fitting garlock fault model had computed left lateral slip rate of 11 plus minus 2 mm yr below 10 km buried left lateral slip of 15 plus minus 6 mm yr on the big pine fault within the western transverse ranges provides significant reduction in line length residuals however deformation there may be more complicated than a single vertical fault a subhorizontal detachment on the southern side of the saf cannot be well constrained by these data the authors investigated the location of the saf and found that a vertical fault below the surface trace fits the data much better than either a dipping fault zone located south of the surface trace less

heavy mineral analysis and provenance of yellow river sediments around the china loess plateau abstract in its upper middle reaches the yellow river has high sand contents after traversing through large areas of desert and the china loess plateau understanding riverbed sediment composition in the channel is critical for the interpretation of the potential provenance aeolian sand transport and the linkage between the loess plateau and the yellow river to address these issues we collected 52 samples from the modern riverbed proximal deserts and major tributaries and used analyses of grain size grain morphology and heavy mineral compositions to establish the spatial distribution and characteristics of source regions and riverbed sediments the heavy mineral assemblages demonstrate significant variations for the different sections of the yellow river the riverbed samples from the upper reach are dominated by opaque minerals limonite and magnetite amphibole and epidote with minor zircon tourmaline and rutile riverbed sediments from the middle reach are garnet rich reflecting the widespread distribution of mesozoic sandstones this variability closely reflects the source regions our data show that seasonal tributaries the ten great gullies carrying detritus from the ordos plateau may account for the localized high garnet concentrations in the inner mongolia section of the upper reach scanning electron microscope sem imaging of quartz grains show that the river sediments are characterized by composite microtextures acquired in both fluvial and eolian environments of the hedong ulan buh and kubuq deserts the mineralogical composition in the upper reach lanzhou yinchuan is similar to that of sediments in the loess plateau and northeast tibet plateau western lanzhou however the composition differs markedly from that in the inner mongolia section of the upper and middle reaches this variation indicates that in the upper reach the northeast tibet plateau contributes significant volumes of sediment to the yellow river and loess plateau but compositions change across the inner mongolia section of the upper and middle reaches owing to local sediment supply from arid desert areas and seasonal tributaries

geomorphic tectonic control of sediment discharge to the ocean the importance of small mountainous rivers analysis of data from 280 rivers discharging to the ocean indicates that sediment loads yields are a log linear function of basin area and maximum elevation of the river basin other factors controlling sediment discharge e g climate runoff appear to have secondary importance a notable exception is the influence of human activity climate and geology on the rivers draining southern asia and oceania sediment fluxes from small mountainous rivers many of which discharge directly onto active margins e g western south and north america and most high standing oceanic islands have been greatly underestimated in previous global sediment budgets perhaps by as much as a factor of three in contrast sediment fluxes to the ocean from large rivers nearly all of which discharge onto passive margins or marginal seas have been overestimated as some of the sediment load is subaerially sequestered in subsiding deltas before the proliferation of dam construction in the latter half of this century rivers

formation of the highest sand dunes on earth characterization of dune morphology has historically been based on relationships between dune forms and wind regimes with dune height shown to be sensitive to atmospheric boundary layer depth sand availability and sediment properties while these parameters have been used in numerical simulations to model the occurrences of some types of dunes they cannot alone explain the great diversity in form and size seen on earth and on other solar system bodies here we present results from our studies of dune formation in the badain jaran desert in western china where earth s tallest dunes occur we measured the variability of the dune morphology in this desert on the basis of landsat etm data and we detected the bedrock landforms beneath the aeolian sands by applying gravity methods wind records from stations at the periphery of the desert and srtm topographical data were examined also to augment the interpretation our studies demonstrate that in addition to average wind parameters dune height is highly sensitive to local geology subsurface characteristics and topography and interactions between changing climate conditions and aeolian and fluvial processes these additional factors need to be considered in the interpretation and simulation of dunes on earth we anticipate that analysis of anomalous dune heights like those seen in the badain jaran may also provide critical information on subsurface characteristics and environmental conditions on earth and on other planetary bodies

nonlinear subsidence rate estimation using permanent scatterers in differential sar interferometry discrete and temporarily stable natural reflectors or permanent scatterers ps can be identified from long temporal series of interferometric sar images even with baselines larger than the so called critical baseline this subset of image pixels can be exploited successfully for high accuracy differential measurements the authors discuss the use of ps in urban areas like pomona ca showing subsidence and absidence effects a new approach to the estimation of the atmospheric phase contributions and the local displacement field is proposed based on simple statistical assumptions new solutions are presented in order to cope with nonlinear motion of the targets

sediment grain size characteristics and its source implication in the ningxia inner mongolia sections on the upper reaches of the yellow river abstract the ningxia inner mongolia nim reaches of the yellow river are characterized by a high sediment load severe siltation large channel migration and frequent dike breaching resulting in substantial social economic and environmental problems for residents along the river therefore studies on the grain size characteristics of sediments in the nim reaches of the yellow river and locating the primary sediment source areas are important for the prevention and mitigation of silt accumulation and the construction of water conservation facilities in this study 361 samples from the yellow river and 178 samples from potential source areas were analyzed large grain sizes in the riverbed and floodplain materials were found in the desert sections and in sections containing 10 tributaries respectively the size of the riverbed and floodplain materials fluctuates relatively frequently in the tributary sections and is coarser at confluences of the tributaries with the yellow river the floodplain material is better sorted than the riverbed material and the sorting coefficients especially the former fluctuate most widely in the tributaries sections two main fractions of the floodplain and most of the riverbed materials in the major river reaches are observed 3 9 63 m and 63 250 m the first fraction component of the riverbed material 63 250 m is found in the desert sections and part of the tributary sections whereas the second fraction component 250 500 m is found in some parts of the desert sections the variations in the size characteristics of the riverbed and floodplain materials demonstrate that both materials are derived from lateral sources the main sources of the riverbed materials are the ulan buh desert and the kubuqi desert in the wuhai zhonghexi reaches and the main sources of the riverbed and floodplain materials are the 10 tributaries in the zhonghexi lama bay reaches the riverbed and floodplain materials in the desert sections are deposited near the source and far from the source respectively both types of sediments in the tributary sections are mainly deposited near their sources through wind and hydraulic sorting the size of the riverbed material in the tributaries sections becomes finer in contrast to that in the desert sections which suggests that coarse sediments have not been effectively carried downstream

mapping landslide surface displacements with time series sar interferometry by combining persistent and distributed scatterers a case study of jiaju landslide in danba china abstract insar technology provides a powerful tool to detect potentially unstable slopes across wide areas and to monitor surface displacements of a single landslide however conventional time series insar methods such as persistent scatterer interferometry psi and small baseline subset sbas can rarely identify sufficient measurement points mps in mountainous areas due to decorrelations caused by steep terrain and vegetation coverage in this study we developed a new insar approach coherent scatterer insar csi to map landslide surface displacements in the radar line of sight los direction by combining persistent scatterers ps and distributed scatterers ds the key ideas of csi include the employment of the generalized likelihood ratio glr test for the identification of statistically homogeneous pixels shps and the use of the phase linking algorithm to estimate optimal phase for each ds pixel the joint exploitation of ps and ds targets dramatically increases the spatial density of mps which makes the phase unwrapping more reliable to demonstrate the effectiveness of the csi approach we applied it to retrieve the historical displacements of the jiaju landslide in danba county of southwest china using 19 l band alos palsar images 2006 2011 and nine c band envisat asar images 2007 2008 multiple comparisons clearly illustrated the big advantages of csi over psi and sbas in mapping landslide displacements with more details owing to much higher 10 times mp density furthermore the superiority of l band sar data over c band for landslide investigation in rural environments was confirmed quantitative validation of the csi results for palsar data against in situ gps measurements suggested an accuracy of about 10 5 millimeters per year mm year in terms of root mean square error rmse afterwards the spatial temporal characteristics of the jiaju landslide surface displacements were summarized with a new upper boundary for the active northern part delineated particularly the northern part of the landslide moved faster than the southern part exhibiting a maximum los displacement rate of around 120 mm year subsequently the fluvial erosion by the dajinchuan river was identified as the predominant impact factor for the instability of the jiaju landslide finally the major problems and challenges for the application of csi method were discussed and the conclusions were given

satellite interferometry for mapping surface deformation time series in one two and three dimensions a new method illustrated on a slow moving landslide abstract space borne differential interferometric synthetic aperture radar dinsar has been extensively used in the last two decades to measure ground surface deformation providing key information for the characterization and understanding of many natural and anthropogenic processes however conventional dinsar technique measures only one component of the surface deformation i e the satellite s line of sight los causing the interpretation of dinsar measurements to be challenging and potentially narrowing the understanding of the mechanisms and dynamics of the deformation processes at work presently available methods that estimate 3d surface deformation from dinsar generally operate on individual interferograms and therefore do not produce 3d surface deformation time series however the availability of time series is essential for studying surface deformation processes bringing information on e g temporally and spatially variable external forcing conditions and characteristics of future deformation patterns the multidimensional small baseline subset msbas method was already able to produce 2d east and vertical surface deformation time series from multi tracks and multi sensors dinsar data here we propose a novel version of the msbas msbas 3d method that can produce 3d north east and vertical surface deformation time series from ascending and descending dinsar data this new method proposes measuring the surface deformation for processes producing motion parallel to the surface such as landslides and glacier flows while conserving the dinsar accuracy the ability of msbas 3d to capture the full 3d deformation pattern of processes with a surface signature is illustrated for a large slow moving deep seated landslide for which long dinsar and dgnss time series as well as ground truth data are available surface deformation is measured over a four year period using 1d los 2d and 3d msbas methods and the advantages and limitations of each approach are described in this case the novel msbas 3d technique produces superior results that greatly simplify interpretation of the processes at work the msbas 3d software can be downloaded from http insar ca

geochemical elements characteristics and sources of the riverbed sediment in the yellow river s desert channel the yellow river flows through an extensive area of aeolian desert and extends from xiaheyan ningxia province to hekouzhen inner mongolia province for a total of 1 000 km in the desert channel of the yellow river the major chemical components are sio2 fe2o3 al2o3 ti cao mgo ba p mn ce co in which sio2 al2o3 fe2o3 and ti have significant value as indicators of the sources of the coarse sediment the spatial distribution of the elements weight percentages and the ratios of si ti si al between sediment sources and riverbed sediment of the gansu reach and the desert channel of the yellow river indicating that the coarse sediments deposited in the desert reach of the yellow river are mostly controlled by the local sediment sources and due to the higher mobility of the fine sediments they are primarily contributed by the local sediment sources and the tributaries that originate from the loess area of the upper reach of yellow river the results of r factor analysis illustrate that the first component score mainly shows negative values in the desert channel suggesting that the coarse sediments in this reach contain a higher content of si and a lower content of mg ca al fe which further proves that the ningxia hedong inner mongolian wulanbuhe and kubuqi deserts are the primary sources of the coarse sediment in the desert channel of the yellow river

using advanced insar techniques to monitor landslide deformations induced by tunneling in the northern apennines italy synthetic aperture radar sar interferometry insar is used to make measurements of small surface displacements in different situations including ground settlement landslides and excavations we document the deformation history of four dormant deep seated landslides in the northern apennines of italy that were reactivated by the excavation of a double road tunnel the tunnel is part of a larger infrastructure project that involves the improvement of the a1 highway which connects bologna and florence the excavation of the tunnel under the landslides basal shear surfaces started in 2011 and with the advance of the tunnel front deformation began to occur causing damages to homes and infrastructures the tunnel passes under the small villages of ripoli and santa maria maddalena the deformation slowed down after the tunnel was completed in november 2014 and low surface displacement rates were registered for the period between october 2014 and june 2016 we show the results of an insar analysis designed to measure surface movements between 2003 and 2016 the insar displacements are derived from the envisat cosmo skymed and sentinel 1 datasets and cover the main construction phase of the tunnel 2011 2015 a detailed geological and geomorphological mapping of the slope is developed based on the field evidence and on the spatial pattern of surface deformation provided by our insar analysis together with the map a new conceptual geological model of the slope in tectonically sheared and weathered flysch is presented the satellite insar data show good agreement with available ground based monitoring data that include inclinometer and gps measurements while small differences occur with respect to deformation time series obtained from a ground based insar instrument in particular the insar results for the x band data of cosmo skymed demonstrate the close relationship between the position of the excavation front and the displacement rates of previously dormant landslide deposits conversely the concurrent rainfall does not appear to significantly influence the observed behavior and if any had only a minor influence on the displacement history of the investigated landslides

a new method for measuring deformation on volcanoes and other natural terrains using insar persistent scatterers 1 we present here a new insar persistent scatterer ps method for analyzing episodic crustal deformation in non urban environments with application to volcanic settings our method for identifying ps pixels in a series of interferograms is based primarily on phase characteristics and finds low amplitude pixels with phase stability that are not identified by the existing amplitude based algorithm our method also uses the spatial correlation of the phases rather than a well defined phase history so that we can observe temporally variable processes e g volcanic deformation the algorithm involves removing the residual topographic component of flattened interferogram phase for each ps then unwrapping the ps phases both spatially and temporally our method finds scatterers with stable phase characteristics independent of amplitudes associated with man made objects and is applicable to areas where conventional insar fails due to complete decorrelation of the majority of scatterers yet a few stable scatterers are present

a study of physico geographical factors for formation of hyperconcentrated flows in the loess plateau of china semi arid climate poor vegetation cover and highly erodible loess can be regarded as the main natural factors responsible for the formation of hyperconcentrated flows on the loess plateau china the degree to which the hyperconcentrated flows develop especially their extreme suspended concentration shows a significant areal differentiation this is closely related to the grainsize composition of suspended sediment an optimal grainsize composition of suspended sediment has been identified which leads to the highest value of extreme concentration among different river basins this optimal composition is related to the combination of three surface material types i e loess wind blown sand and weathered bedrock and it occurs as a result of seasonally alternating wind and water processes operating in this area

provenance of eolian sands in the ulan buh desert northwestern china revealed by heavy mineral assemblages abstract accurate identification of the provenance of eolian sand in deserts is essential to study sedimentation processes in the earth system exposed bedrock surrounding the desert has been regarded as the main source of eolian sand in some deserts of the world however few studies have focused on whether paleolacustrine deposits and bedrock outcrops in desert hinterlands are the main sources of eolian sand in this study we selected the ulan buh desert in northwestern china as the study area and a total of 99 samples were collected throughout the desert and nearby regions to study the provenance of the current eolian sand based on their heavy mineral assemblages and contents the results showed similar heavy mineral assemblages among the eolian sand the bedrock to the northwest of the desert and the paleolacustrine deposits and exposed bedrock in the desert hinterlands suggesting multiple provenance for the eolian sand in the ulan buh desert the sources of the eolian sand in the ulan buh desert include bedrock to the northwest gobi to the west and paleolacustrine deposits and exposed bedrock in the desert hinterlands helan mountains bedrock and yellow river fluvial deposits near the desert contribute little to the eolian sand moreover the paleolacustrine deposits and exposed bedrock in the desert hinterlands should not be neglected as the potential provenance of eolian sand in other studies this study enhances understanding the provenance of eolian sand in the deserts of northern china

quantifying sand provenance and erosion marsyandi river nepal himalaya we use petrographic and mineralogical data on modern sediments to investigate erosion patterns in the marsyandi basin of the central himalaya a privileged natural laboratory in which a series of multidisciplinary geomorphological sedimentological geochemical and geochronological studies have been recently carried out to unravel the interrelationships between tectonic climatic and sedimentary processes in high relief orogenic belts although relative erosion patterns are effectively constrained by analyses of replicate samples along six successive tracts of the marsyandi river uncertainties are caused by potential compositional variation between the monsoon and post monsoon season estimates of erosion rates are significantly affected by poor knowledge of total sediment flux through the basin ourresults support focusederosion of the southern tectonically lower part of the greater himalayain the hangingwall of the mct zone where thesummer monsoon reachesitspeak intensity up to 5 m a andsediment yieldsanderosion ratesreach14 100 3400t km 2 and 5 1 1 2 mm a erosion rates sharply decrease southward in low relief lesser himalayan units 1 6 0 6 mm a and also progressivelydecreasenorthwardsinthehigh altitude tectonically upperpartofthegreaterhimalaya whererainfalldecreasesrapidly to b2 m a even areas of extreme topography such as the manaslu granite are characterized by relatively low erosion rates 2 4 0 9 mm a because precipitations become too scarce to feed significant ice flux and glacial activity monsoonal rainfall decreases further tob0 5 m a in the tethys himalayan zone farther north where erosion rates are 1 mm a coupling between erosion and peak monsoonal rainfall along the southern front of the greater himalaya is consistent with both channel flow models of tectonic extrusion

mineralogy of the core yrd 1101 of the yellow river delta implications for sediment origin and environmental evolution during the last 1 9myr abstract in this study we report the high resolution heavy mineral records from a 200 30 m long borehole yrd 1101 on the northern coast of modern yellow river delta yrd covering the last 1 90myr the results show that the heavy mineral assemblages are dominated by epidote followed by hornblende garnet and hematite limonite in the yellow river yr sediments the content of hornblende is higher than the epidote and the epidote to hornblende ratios e h are lower than the core yrd 1101 the e h show two distinct lower values at depositional unit du 4 2 117 9 125 6 m and du 4 1 to du 2 13 5 99 3 m indicating the obvious influence of yr sediments the heavy mineral composition of du 5 is distinct from yr sediments and interpreted as the result from heterogeneous provenance of the adjacent ancient rivers while du 4 to du 1 resemble the upper middle reaches of the yr sediments the different sediment types mud sandy silt and silt of core yrd 1101 do not contain markedly different transparent heavy mineral assemblages in terms of concentration and mineral ratios no matter how sedimentary environment changes the ratios of epidote and hornblende show very stable values in du 4 1 and du 3 due to the influence of yr sediments the transparent heavy minerals such as hornblende epidote and other stable minerals which were relatively stable are controlled primarily by provenance while the sedimentary environment mostly influences the flaky minerals and the authigenic minerals this study provides evidence regarding the history of the lower reaches of the yr and yrd since the early pleistocene highlighting river s important role for the evolution of the western coast of the bohai sea bs

source to sink transport in the oligocene huagang formation of the xihu depression east china sea shelf basin abstract the huagang formation is the most important hydrocarbon reservoir in the xihu depression of the east china sea shelf basin reconstructing the provenance and transport pathways of its main sand bodies is of great significance to oil and gas exploration previous provenance studies were mainly based on heavy mineral analyses and showed multiple source areas but so far quantitative estimates on provenance are lacking detrital zircon u pb dating combined with heavy mineral analysis is an effective tool to quantitatively investigate sediment provenance in this paper we use the la icp ms method for u pb dating of detrital zircons of 18 samples from 13 drill cores in the xihu depression to determine the sediment provenance of the oligocene huagang sandstones the u pb zircon dating results show three different age groups in which precambrian ages dominate 60 and paleozoic and mesozoic ages each account for 20 the precambrian zircons are mainly derived from the hupijiao uplift which indicates a dominant and long distance north to south transport direction the provenance of the paleozoic zircons is mainly from the diaoyu islands folded uplift belt in the east while the haijiao and yushan uplifts in the west are the main source region for the mesozoic zircons the northern provenance transport pathway is dominated by axial channels incised valleys are observed in the western source and a transfer zone dominates the eastern provenance the integration of all data results in a new schematic model of source to sink transport in the huagang sandstones demonstrating the complexity of multiple source rocks and sediment transport pathways in the oligocene xihu depression

dynamics of slow moving landslides from permanent scatterer analysis high resolution interferometric synthetic aperture radar insar permanent scatterer data allow us to resolve the rates and variations in the rates of slow moving landslides satellite to ground distances range changes on landslides increase at rates of 5 to 7 millimeters per year indicating average downslope sliding velocities from 27 to 38 millimeters per year time series analysis shows that displacement occurs mainly during the high precipitation season during the 1997 1998 el nino event rates of range change increased to as much as 11 millimeters per year the observed nonlinear relationship of creep and precipitation rates suggests that increased pore fluid pressures within the shallow subsurface may initiate and accelerate these features changes in the slope of a hill resulting from increases in the pore pressure and lithostatic stress gradients may then lead to landslides

tidal current dominated depositional environments in the central northern yellow sea as revealed by heavy mineral and grain size dispersals abstract this study confirms that the fine sand sized detritus in the central northern yellow sea is chiefly derived by the yellow river and explains the holocene yellow river dispersal system and the preservation of transgressive deposits by heavy mineral and grain size analyses micas which are sensitive to hydraulic sorting offer an effective key for identifying the dispersal of holocene yellow river derived fine grained sediments the heavy mineral compositional changes are attributed to hydraulic sorting by different marine dynamics and various mixing with additional local transgressive deposits of miscellaneous provenance the effects of hydraulic sorting are dominated by holocene tidal currents and by foreshore waves during the rapid transgression respectively the former results in obvious enrichments of garnet and common stable species such as ti oxides tourmaline and titanite whereas the latter seems more remarkable for the compositional changes with further depletion of epidote actinolite tremolite and zoisite clinozoisite the central yellow sea mud deposit and the alongshore muddy zone off the southern liaodong peninsula are opposite to each other as a pair of structurally symmetric coalesced terminal lobes far away from the high energy strait between cape chengshan and changsan got the haiyang subaqueous clinoform as another terminal lobe is revealed by a heavy mineral index which represents an extremity of deposits accumulated by the modern yellow river derived sediments off the southwestern shandong coast a small mud patch is revealed roughly corresponding to the central regime of the amphidromic system of principal m2 constituent the tidal current dominated depositional pattern proposed here emphasizes the importance of time velocity asymmetry of tidal currents such a dynamic mechanism is primarily responsible for the dispersal of the modern yellow river derived sediments when they are entrained from the bohai sea to the south yellow sea through the bohai strait and the strait between cape chengshan and changsan got

detection and displacement characterization of landslides using multi temporal satellite sar interferometry a case study of danba county in the dadu river basin abstract detection of potential slope instabilities across wide areas using sar interferometry insar techniques can aid prevention and mitigation of landslide disasters nevertheless the low spatial density of coherent radar targets detected by conventional time series insar methods in mountainous areas with complex topography and vegetation cover introduces considerable uncertainties into the deformation measurements and thus results in a high probability of omissions for landslide detection in this study a new time series insar method named coherent scatterers insar csi is proposed to solve this problem through the joint exploitation of persistent scatterers ps and distributed scatterers ds to increase the quantity of measurement points mps in rural environments we applied this approach to detect potentially unstable slopes at a catchment scale delineate sliding boundaries and measure the deformation of major landslides the archived alos palsar and envisat asar data stacks covering the danba county in the upper reach of the dadu river basin in southwest china were processed the palsar measured deformation rate map revealed 17 suspected landslides and their sliding boundaries by contrast only six out of these 17 landslides were detected from the asar results as the other 11 landslides were undetected due to the much lower density of coherent points these detection results were indirectly verified by two different approaches two differential interferograms for recently acquired l band alos 2 palsar 2 data pairs were visually inspected to check whether these landslides are still in active deformation the reliability of the insar results was further evaluated by comparisons against field survey and in situ gps measurements the spatial and temporal patterns of surface displacements at several slow moving landslides were analyzed in detail and general guidelines on the application of the csi method for landslide investigations were discussed and summarized

investigating landslides with space borne synthetic aperture radar sar interferometry abstract this paper is addressed to readers without advanced knowledge of remote sensing it illustrates some current and potential uses of satellite synthetic aperture radar interferometry insar for landslide assessment data acquired by sar systems can provide 3d terrain models and be used to assist in regional scale investigations e g aimed at evaluation of susceptibility of slopes to failure under favourable environmental conditions the innovative permanent scatterers ps technique which overcomes several limitations of conventional sar differential interferometry dinsar applications in landslide studies is suitable for monitoring slope deformations with millimetric precision the ps technique combines the wide area coverage typical of satellite imagery with the capability of providing displacement data relative to individual image pixels with the currently available radar satellites however only very slow ground surface displacements can be reliably detected and measured the presented case study of a landslide from the liechtenstein alps indicates that the most attractive and reliable contribution provided by this remote sensing technique lies in the possibility of i wide area qualitative distinction between stable and unstable areas and ii qualitative relative hazard zonation of large slow landslides based on the identification of segments characterised by different movement rates since only the radar line of sight projection of the displacements can be detected a quantitative exploitation of the ps data is possible only where sufficient ground truth is available in site specific or single landslide investigations the ps data can represent a very useful complementary data source with respect to the information acquired through ground based observations and in situ surveying however the difficulties associated with the feasibility assessments of the applicability of sar data to local scale problems as well as with the interpretation of ps results require a close collaboration between landslide experts and specialists in advanced processing of radar satellite data the interpretation of the exact geotechnical significance of small radar sensed ground surface deformations is challenging especially where ground truth is lacking although any ground deformation is potentially of interest to an engineering geologist detection of movements in both vertical and horizontal directions is needed in the case of landslides to evaluate slope failure mechanisms with their high radar viewing angles however the current space borne systems can detect only a fraction of the horizontal component of movement it is expected that the upcoming sar dedicated missions with new sensors and different acquisition geometries combined with the rapid developments in the field of advanced radar data processing will allow a full 3d reconstruction of deformation data and help to further reduce the current limitations of the ps and similar dinsar approaches

surface displacements of the heifangtai terrace in northwest china measured by x and c band insar observations abstract the heifangtai terrace located in yongjing county of gansu province in northwest china is characterized by a large number of landslides with frequent failure events related to agricultural irrigation activities thus it is a task of great importance to identify and monitor the active loess slopes and sort out the impact factors in this study we employed the time series insar method to map the active slopes in the heifangtai terrace with two terrasar x data stacks covering the year of 2016 and two sentinel 1 data stacks from 2016 to 2018 the detected active spots are mainly distributed along the edges of the terrace time series displacements derived from terrasar x and sentinel 1 observations were validated by comparisons against gps and crack gauge measurements good agreement between insar and gps was achieved at slow moving locations while unwrapping errors induced by sudden accelerations make insar underestimate the pre failure displacements with respect to gps measurements the trends of insar measured displacement and crack gauge measurements also match well with correlation higher than 0 75 insar measured displacements at the jiaojia landslide group were highly correlated with the bury of groundwater record which suggested that the rising of groundwater level may seriously decrease the stability of loess slopes

how and when did the yellow river develop its square bend the current course of the yellow river china involves an unusual 1500 km long angular bend around the ordos tectonic block although sedimentary evidence suggests that the river once followed a more direct path eastward into the bohai sea geologic evidence reveals that the yellow river formed in the eocene as an eastward draining river and developed its square bend around the ordos block in late miocene early pliocene time as a result of folding and uplift that are most probably related to the collision and penetration of india into eurasia as well as rifting around the ordos block the change in course of the yellow river predates flat lying pliocene pleistocene sediment deposits that unconformably overlie folded eocene miocene strata the yellow river provides a typical example of tectonic controls on the size morphology and longevity of rivers

provenance discrimination of upper yangtze river basin sediments new insights from heavy mineral signatures and detrital magnetite geochemistry abstract magnetite is typomorphic and its crystal textures and chemical fingerprint form unique signatures that can be used to determine sediment provenance determination of the provenance of sediments in the upper yangtze river is critical for understanding its evolution and the uplift of the tibetan plateau in this study petrographic analysis and electron probe microanalysis epma of 800 detrital magnetite grains were performed to differentiate the provenance of sediments within the mainstream and major tributaries of the upper yangtze river catchment chemical analyses show that the elemental composition of magnetite grains shows pronounced variations among the different sections of the mainstream and tributaries based on the observed chemical fingerprints we infer that the source rocks control the elemental composition of magnetite grains the magnetite contribution is closely related to the tectonics climate and erosion of parent rocks within different drainage basins magnetite from the trunk stream of the jinsha river is found to be a significant contributor to the upper yangtze river magnetite grains of the upper jinsha river are primarily derived from source areas composed of silicic plutonic rocks and ophiolite lithologies that crop out on the se tibetan plateau magnetite grains within the sands of the lower jinshajiang sediments are characterized by high concentrations of ti mg cr al and mn and are derived from the widely distributed emeishan flood basalts and pan xi layered basic ultrabasic igneous rocks this source is also a major contributor of magnetite to the upper yangtze river and the parent rock distributed in this region is of typomorphic significance to the development of the yangtze river the origin of magnetite grains in the tributaries depends on the parent rocks distributed in their catchments in summary the presence of detrital magnetite grains provides valuable information for discriminating the provenance of sediments in the upper yangtze river drainage basins

surface textural analysis of quartz grains by scanning electron microscopy sem from sample preparation to environmental interpretation abstract surface microtextures on quartz grains provide an insight into the sedimentary history of clastic sediments not only information on the depositional environment is provided but also in some cases successive sedimentary cycles can be recognised sample preparation and sem imaging are the initial and therefore crucial steps in the study of microtextures a sample preparation procedure using 15 hydrochloric acid and 50 g l tetrasodium pyrophosphate solutions removes most of the grain coatings and adhering particles the study of microtextures on 1300 quartz grains from a wide variety of environments was complemented with the reference works and atlases krinsley and doornkamp 1973 le ribault 1977 higgs 1979 mahaney 2002 to construct an interpretation scheme allowing to differentiate between fluvial marine eolian glacial and diagenetic alteration environments based on microtextures in a case study the known littoral setting of two samples was confirmed by using the interpretation scheme for quartz microtextures furthermore successive reworking of the grains in eolian and intertidal environments was recognised by presenting the research of microtextures from starting point to interpretation new researchers may find this review a useful and practical introduction into the technique

improved correction of seasonal tropospheric delay in insar observations for landslide deformation monitoring abstract synthetic aperture radar interferometry insar provides an effective tool to study slow moving landslides however insar observations are often contaminated by tropospheric artefacts due to spatial and temporal variations of atmospheric refractivity particularly the topography dependent stratified delays may introduce seasonal oscillation biases into insar measured deformation time series under steep terrains which cannot be removed by conventional spatial and temporal filtering in this study we proposed two complementary approaches to correct the stratified tropospheric delays for time series insar analysis when studying single landslides one is the iterative linear model ilm as an improved version of the traditional linear model lm the other is to fuse tropospheric delays predicted by several global weather models fdwm with different temporal intervals and spatial resolutions both methods are integrated into the standard small baseline subset sbas time series analysis procedure we evaluated the proposed methods in three landslide prone areas in southwest china using sentinel 1 datasets the experimental results demonstrated that the ilm method removed the seasonal stratified delays mixed in deformation time series unaffected by the deforming points the fdwm method achieved an optimal combination of tropospheric delay predictions by four weather models i e era interim era5 hres ecmwf and merra 2 validations using in situ gps measurements suggested that the original root mean squared rms values of interferometric phases declined by more than 35 after both ilm and fdwm corrections the ilm had better performances than the fdwm to correct stratified delay for single landslides whereas the fdwm can be an effective alternative when the ilm is inapplicable in case of limited coherent points