evaluation of relative tectonic perturbations of the kashmir basin northwest himalaya india an integrated morphological approach abstract geomorphic and morphotectonic evaluations of the kashmir basin have been carried by implicating different geomorphic indices such as stream gradient index sl hypsometric integral hi drainage basin asymmetry af valley floor height and width ratio vf transverse topographic symmetry factor t mountain front sinuosity smf drainage basin shape bs and sinuosity index si for the categorization of relative index of active tectonics riat through the use of geographic information systems gis so as to decipher the role of neotectonics in geomorphologic evolution of the basin the verified riat classes through field investigation and validation reveal the traverse of twenty one active faults in the basin with demarcation of three riat classes viz class 1 inactive 20 07 of the area class 2 moderately active 36 52 of the area and class 3 very active 43 4 of the area the observed values of riat distribution pattern are well corroborated with field observations ultimately the overall geomorphic outputs and clustering of recent seismicity support the active tectonic control over the kashmir basin india

tectonic forcing of drainages and geomorphic features developed across himalayan mountain frontal part of western limb of siang antiform arunachal himalaya drainages display tectonic forcing of their channels on the frontal region of the arunachal himalaya due to structural control dikari a transverse river flowing along the n s trending western limb of the major siang antiform exhibits structurally controlled nature of its drainage on its downstream flow towards south through a network of ne sw and nw se trending conjugate faults the river shows compressed meandering as the regional structural trend of ene wsw seems to be reactivated by the transverse nw se trend of neotectonic fault activity the himalayan frontal thrust hft tracing along the himalaya mountain front has been displaced sinisterly for a distance of 7 km by a wnw ese trending fault running along the sileng stream development of parallel drainages in the southern part of the sub himalaya is interpreted to have formed as a result of uplifting related to the above mentioned strike slip movement along the hft zone the frontal streams and rivers exhibit deflection of their channels from ne sw to ene wsw directions channel of the transverse siang river has been deflected for a length of 3 km along the nne ssw direction across the himalayan frontal part in this part of the himalaya previous workers did not give much emphasis on the role of siang antiform as far as neotectonic with respect to the tectonics related to the hft is concerned there is a syntectonic relationship between the active ne sw oriented compression direction and the tectonic forcing of the drainages including development of the tectonic geomorphology

asymmetrical valleys created by the geomorphic response of rivers to strike slip fault abstract offset fluvial valleys including rivers beheaded and deflected by strike slip faults have long been used to estimate horizontal displacements on the faults larger rivers crossing such faults however sometimes show either no offset or only a small amount of offset compared to smaller rivers crossing the same faults the larger rivers with higher erosional rates may widen their valleys asymmetrically downstream of strike slip faults rather than being beheaded or deflected examples are described from the yellow river near the ne margin of the tibetan plateau river beheading and asymmetrical widening are two end members of a fluvial valley s response to strike slip faulting whereas deflection is a combination of both recognition of the formation of such asymmetrical valleys related to strike slip faulting will help to understand fault activity better over longer time spans and enable a re evaluation of many fault histories worldwide

long lived deformation in the southern mississippi embayment revealed by high resolution seismic reflection and sub bottom profiler data three high resolution seismic reflection profiles and two sub bottom profiler sections acquired along the mississippi river in southern central u s image deformation in post paleozoic sediments the northernmost profile images two faults offsetting cretaceous through at least eocene cane river reflectors interpreted to strike northwest and to be part of the arkansas river fault zone the central profile shows a down to the north fault displacing cretaceous and paleocene midway group reflectors by 210 m and 160 m respectively the fault is interpreted as the northern edge fault of the monroe uplift a late cretaceous uplift associated with igneous intrusions the southernmost profile displays a down to the south fault offsetting cretaceous and paleocene eocene wilcox group reflectors by 125 m and 32 m respectively tilted reflectors in the first 80 m indicate eocene oligocene activity of the fault although quaternary activity cannot be ruled out quaternary tectonic activity is proposed for a series of faults that offset shallow 40 m depth eocene sequences and the base of the quaternary alluvium as imaged on two sub bottom profiler sections these shallow faults are imaged in the vicinity of holocene earthquake induced liquefaction fields corroborating the evidence for recent tectonic activity in the area the spatial coincidence of the imaged faults with the inferred location of the alabama oklahoma transform strongly argues toward a long lived influence of this precambrian continental margin in focusing tectonic activity in the southern u s by controlling the reactivation of triassic jurassic syn rift basement structures and guiding the emplacement of late cretaceous igneous intrusions and the location of cenozoic deformation

tectonic geomorphology of the southeastern mississippi embayment in northern mississippi usa we analyzed drainage basin geometry in part of the southeastern mississippi embayment near the new madrid seismic zone in order to detect areas of lateral stream migration that could indicate recent tectonism toward this goal a field of drainage basin asymmetry vectors was generated from a digital terrain model and compared to geologic structure lithofacies seismicity remotely sensed lineaments and major drainage divides transverse topographical drainage basin asymmetry t index results define geomorphic domains in northern mississippi 33 to 35 n 88 5 to 90 25 w that may reflect deep crustal blocks bounded by active faults or flexures t index measurements a proxy for lateral stream migration of more than 4500 second order drainage basins produced a two dimensional field of 282 spatially averaged vectors from which we interpreted 12 domains some domain boundaries correspond to mapped faults of two paleozoic fault systems in our study area the northeast striking mississippi valley graben system and the northwest striking ouachita thrust belt and foreland faults several other prominent domain boundaries may be previously unmapped faults flexures parallel to these systems this interpretation is supported by satellite image analysis of the northeastern study area which reveals lineaments consistent with our domain boundaries that have strikes that reflect the regional subsurface structural grain

tectonic geomorphology of a large normal fault aksehir fault sw turkey abstract in order to better understand the activity of the aksehir normal fault in sw turkey and the associated seismic hazard we investigated the tectonic geomorphology of a 60 km stretch of the 100 km long aksehir fault block the fault can be separated into seven geomorphic segments 1 to 7 from nw to se along the mountain front segment length varies from about 9 to 14 km and relief of the horst block varies from about 0 6 km in the se to 1 0 km in the nw analysis of the tectonic geomorphology of 32 drainage basins and mountain front facets using a combination of geomorphic indices reveals a general pattern of high slip rates in the northern and central segments and low slip rates in the southern probably older segments we show that mountain front sinuosity varies from about 1 1 to 1 4 on segments s1 s6 to 2 4 on segment s7 suggesting that the six northern segments are more active than the southernmost segment similarly analysis and slope area analysis of streams reveal a pattern of steepest channels draining the central and northern segments of the horst the ratio of valley floor width to valley height varies from 0 2 to 0 6 which are typical values for tectonically active mountain fronts and alluvial fans along segments s1 s2 and s4 are back tilted finally we show that 1 shapes of the 100 900m high mountain front facets are mostly triangular 80 and partly trapezoidal 20 2 facet slopes range from 6 to 22 3 facets at the nw and se segment ends are larger than the intervening facets and 4 steepest facets occur along the central segments uplift rates estimated from the slope of mountain front facets range from about 0 06 m ky on the southernmost fault segment s7 to 0 23 m ky on the more central s5 and 0 16 m ky on the northern segment s1 the estimated pattern of uplift is consistent with the pattern of geomorphic indices the vertical relief of the facets suggests that uplift of the mountain front initiated in the late miocene early pliocene and continues to the present with the earliest surface rupturing faults on the southernmost fault segment s7 large normal faults with a similar slip rate of 0 2 0 3 m ky typically have strong earthquakes every few thousand years therefore the many moderate to strong earthquakes on the aksehir fault in the past few hundred years may be misleading a paleoseismic evaluation could answer questions concerning the area s earthquake hazard the tectonic geomorphology suggests that the aksehir fault is active and larger earthquakes than those of the historic period are a potential threat

insights into deglaciation of the largest ice free area in the south shetland islands antarctica from quantitative analysis of the drainage system abstract a quantitative geomorphic analysis of the drainage system on byers peninsula livingston island has been carried out in order to study the relief evolution glacial history and possible neotectonic influence on the largest ice free area of the south shetlands archipelago aerial photographs sar data from radarsat 2 satellite field work a digital elevation model and gis spatial analysis have been used to identify map and study the existing drainage basins a series of morphometric parameters have been studied in 30 selected basins in order to characterize their shape as well as the drainage network results in morphometric parameters reveal elongation trends in the shape of basins and a limited hierarchical network common of a youthful stage of landscape evolution models several morphometric indexes hypsometric integral hypsometric curves sl index transverse topographical drainage basin asymmetry t factor have been used to study possible controls on drainage development results have been discussed in relation to relief and drainage evolution linked to the spatial distribution of lithological units and structural framework t factor shows an apparently disorganized pattern and absence of tectonic influence however there are local values of second order basin asymmetry directions and magnitudes which could reflect a succession of master rills through time related to the changes in water supply during the deglaciation history of byers peninsula hypsometric values and curves of basins are also mainly related to a young stage of landscape evolution analysis of hypsometric integrals together with t factor index has allowed us to establish a possible deglaciation model on byers peninsula which successfully explains the results areas of different landscape evolution stage are linked in space and support the hypothesis of local glacial centers during the ice cover retreat process sl index results do not show the same pattern in results which could be due to differences between incision and lateral shifting ratios quantitative geomorphic analysis indicates that during the deglaciation of byers peninsula at least three areas acted as local glacial centers nw central and rotch dome area changes in index results clearly show a different behavior between two areas distal areas and proximal areas close to the glacial centers morphometric indexes have demonstrated their being useful tools to provide information on the glacial history in recently deglaciated antarctic areas

application of geomorphic indices to address the foreland himalayan tectonics and landform deformation matiali chalsa baradighi recess west bengal india abstract in the himalayan foreland basin of the tista jaldhaka system of north bengal the presence of main boundary thrust mbt and himalayan frontal thrust hft along an e w direction has been reanalysed in the context of tectonic instability especially along the 17 93 km stretch of the kurti river it is a small rain fed stream that originated in the piedmont zone near the samsing scarp lineament trending e w this work discusses in detail the control of active matiali chalsa and baradighi faults that has been determined by the river morphometric aspects deformed landform as terraces and the valley incision mechanism over time we document not only the fault scarps as mbt near matiali and hft near chalsa but also decipher the baradighi fault as a local manifestation of tectonism with well exposed scarps a ramp anticline synformal zone i exists between the northernmost part of the matiali scarp mbt and towards the south near the chalsa scarp hft however to the south of chalsa lies another depression zone synformal zone ii that extends up to the baradighi scarp exposed in the left eastern side of kurti river changes in geomorphic indices such as long profile analysis drainage basin asymmetry hypsometric curve valley floor width to height ratio vfwh concavity index transverse topographic symmetry factor and sinuosity index along the kurti river have been evaluated uplift erosion cycle with valley incision between the mbt hft and hft baradighi fault scarp connotes that the foreland tectonics emerged to be the recent evolutionary phases in the tecto morphological study

application of diffracted wave analysis to time lapse seismic data for co2 leakage detection time lapse seismic analysis is utilized in co2 geosequestration to verify the co2 containment within a reservoir a major risk associated with geosequestration is a possible leakage of co2 from the storage formation into overlaying formations to mitigate this risk the deployment of carbon capture and storage projects requires fast and reliable detection of relatively small volumes of co2 outside the storage formation to do this it is necessary to predict typical seepage scenarios and improve subsurface seepage detection methods in this work we present a technique for co2 monitoring based on the detection of diffracted waves in time lapse seismic data in the case of co2 seepage the migrating plume might form small secondary accumulations that would produce diffracted rather than reflected waves from time lapse data analysis we are able to separate the diffracted waves from the predominant reflections in order to image the small co2 plumes to explore possibilities to detect relatively small amounts of co2 we performed synthetic time lapse seismic modelling based on the cooperative research centre for greenhouse gas technologies co2crc otway project data the detection method is based on defining the co2 location by measuring the coherency of the signal along diffraction offset traveltime curves the technique is applied to a time lapse stacked section using a stacking velocity to construct offset traveltime curves given the amount of noise found in the surface seismic data the predicted minimum detectable amount of co2 is 1000 2000 tonnes this method was also applied to real data obtained from a time lapse seismic physical model the use of diffractions rather than reflections for monitoring small amounts of co2 can enhance the capability of subsurface monitoring in co2 geosequestration projects

geomorphic evolution of a non glaciated river catchment in lesser himalaya response to tectonics abstract the study discusses detail valley formation and sedimentation processes in the monsoon dominated non glaciated catchment of the ramganga river in the lesser himalaya the geomorphic and sedimentological studies in this basin indicates phases of massive aggradation that was controlled mainly by channel bound processes and debris flows landslides the luminescence chronology of the fill sequences suggests that the valley filling occurred mainly in response to the enhanced monsoon after the last glacial maxima lgm during medieval warm period mwp and little ice age lia this phase is common in both glaciated and the non glaciated catchments of himalaya the ramganga river that flows through various tectonic structures of the lesser himalaya shows development of wide valleys with thick fill deposits in the fault zones chaukhutiya fault cf and binau bhikiyasain naurar fault bbnf are the two main transverse faults where the evolved geomorphology pertains to their tectonic activity the computed morphometric variables such as ratio of valley floor width to valley height vf and stream gradient index sl show higher values in the transverse fault zones basin asymmetry vectors along the south almora thrust and bbnf are characterized by preferred stream migration in ne and sw direction suggesting bbnf with dip slip movement thick clay deposits at different sites along the ramganga river resulting from blocking of the river particularly along the bbnf also point towards tectonically induced landslide and channel blockage later phase of tectonic activity bracketed between 27 and 24 ka is evident from deformed fluvial deposits in the form of folds and faults evidences of tectonic activity in the form of soft sediment deformation structures ssds generic to seismic activity in layers comprising alternation of clay and sand are observed in the himalayan frontal thrust hft zone the diagnostic features such as dykes faults and folds suggests that the shaking event took place between 38 ka and 30 ka

inner forearc response to subduction of the panama fracture zone southern central america abstract subduction of the right lateral panama fracture zone along the convergent margin of central america creates abrupt lateral variations in convergence rate obliquity and subducting crustal thickness at its intersection with the middle america trench this intersection known as the panama co nz ca triple junction is migrating to the southeast at a rate of 55 mm yr and currently coincides with the lateral termination of the fila costena thrust belt in the inner forearc of the overriding plate mapping in the inner forearc in the area that straddles the subducting panama fracture zone reveals that cocos caribbean convergence west of the triple junction leads to the development of an inner forearc thrust belt inboard of the colliding cocos ridge while little deformation is evident inboard of nazca caribbean convergence east of the triple junction this results in the lateral termination of the fila costena thrust belt in the region of the forearc that projects over the panama fracture zone where four out of five mapped thrust faults tip out and are buried by lahars three new balanced cross sections indicate a steep gradient in shortening from the center of the thrust belt to its southeastern termination the short term history of the inner forearc recorded in the landscape and topography of the fila costena is consistent with the southeastward migration of the thrust belt and the panama triple junction throughout the past 3 ma with evidence for the growth of a new topographic divide and reorganization of stream channel networks

high altitude plio quaternary fluvial deposits and their implication on the tilt of a horst western anatolia turkey abstract this study investigates the origin and regional tectonic implications of high altitude plio quaternary fluvial deposits developed over the bozdag horst which is an important structural element within the horst graben system of western anatolia turkey a total of 23 deposits occur near the modern drainage divide comprising fluvial to occasionally lacustrine deposits the deposits are all elongated in n s direction with a width length ratio of 1 10 the largest of them is of 13 km in length with a maximum observable thickness of about 100 110 m morphological lithological deformational characteristics of these deposits and the drainage system of the area all suggest that the deposits were formed due to uplift and southward tilting of the bozdag horst this tilting which is estimated as 1 2 to 2 2 caused accumulation of the stream load along channels flowing from south to north all the deposits were later dissected by the same streams with the exception of one deposit which still preserves its original lake form these deposits are of quaternary age which corresponds to the latest n s directed extensional tectonic phase in the region

morphotectonic evidence from the southern branch of the north anatolian fault naf and basins of the south marmara sub region nw turkey this study investigated the morphotectonic evidence from the southern branch of the north anatolian fault naf and the south marmara sub region nw turkey the south marmara sub region has two uplifts located in the south and north and a depression between these uplifts the uplifts are bounded by the southern branch of the naf the southern branch is divided into the yenice gonen ygfz manyas mustafakemalpasa mmf uluabat ufz and bursa bfz faults the relation between the active tectonics and recent morphology were evaluated by using the geomorphic indices gis af asymmetry factor t topographic symmetry factor sl river length gradient index smf mountain front sinuosity gis were used to define the effects of tectonism on morphology and were used to calculate the relative tectonic activity index iat the values obtained through the gis indicate a young tectonism in the study area the study area morphometrically presented two iat classes class 1 high relative tectonic activity and class 2 moderate relative tectonic activity the present gps data and iat classes of the southern branch faults of the nafz were correlated all of the calculations and field data reveal that the southern branch of the naf is the main tectonic element forming the geomorphology of the south marmara sub region

3d diffraction imaging of linear features and its application to seismic monitoring many subsurface features such as faults fractures cracks or fluid content terminations are defined by geological discontinuities the seismic response from such features is encoded in diffractions we develop an algorithm for imaging such discontinuities by detecting edge diffractions the algorithm exploits phase reversal phenomena of edge diffractions and uses them as a criterion to separate these diffractions from specular reflections and diffractions produced by a leaner object the performance of the method is demonstrated on both synthetic and real 3d seismic data the output image focuses the diffracted energy back to its origin and shows high semblance values at the edge of the object the method is applied on conventionally stacked data producing an image that contains only diffraction events called the d volume we also reveal the potential of diffractions to image and track the changes of a co2 plume using time lapse analysis and detect any possible co2 seepage from its primary containment

geomorphological response of fluvial and coastal terraces to quaternary tectonics and climate as revealed by geostatistical topographic analysis geostatistical topographic analysis is widely recognized as a useful tool for the statistical reconstruction of planar geomorphic markers from relict surfaces this work is aimed at improving the geostatistical approach used in previous works and developing a method for evaluating the incision rates of rivers in their lower catchments during the late quaternary we chose the major valleys of the adriatic foothills central italy affected since late miocene by a differential tectonic uplift which is still active in particular i we applied the geostatistical analysis to reconstruct the original top surfaces of fluvial to coastal terrace bodies at the metauro river and cesano river mouths ii we performed correlations between the height distribution of the alluvial terrace sequences and the quaternary climatic curve to estimate the average long term fluvial incision rates in the lowermost reaches of the metauro cesano misa and esino rivers the obtained averaged incision rates have been interpreted also in the light of the stream length gradient index sl index steepness index ks and concavity index as proxies of the stream power per unit length results confirm that geostatistical and terrain analysis of topographic and geometric arrangements of fluvial and coastal terraces is an effective tool in detecting geomorphic and tectonic factors inducing perturbations on planar geomorphic markers in particular we better delineated the surface geometry and boundaries of well developed coastal fans at the mouths of the metauro and cesano rivers already recognized in previous works through sedimentological morphostratigraphic and chronological data moreover we found evidence for cut and fill phases that took place during and immediately after the river aggradation of the late quaternary glacial periods despite the slope area analysis evidenced a widespread influence of the regional differential uplift on single river basin configuration we observed some space and time variability of averaged incision rates for adjacent valleys mainly explained by physiographic configuration and dynamics of drainage network copyright 2011 john wiley sons ltd

repeatability study of seismic source signatures this study discusses the repeatability of source signature using the instantaneous phase as derived from the complex trace attributes the study is part of a very large 2 d seismic survey using sources of vibroseis and surface dynamite the field procedure consisted of recording the production record retaining the positions then repeat recording the same shake or shot the instantaneous phase was found to be the best measure for the difference between the first and the repeat records in addition to the instantaneous phase other analyses were used to evaluate changes in source signature results were tabulated for statistical comparisons and graded for quality excluding erroneous cases the remainder of poor repeatabilities were studied the analyses of near offset data seem to indicate that nonrepeatability of source signature relates mostly to changes in absorption and cohesion induced by elastic saturation at the near surface in general by time shifting and phase rotating the repeat record the difference in instantaneous phase tends to diminish the new idea of using instantaneous phase difference plots to evaluate repeatability offers improved evaluation of source signatures and can also be used to detect time lapsed changes in reservoir monitoring by evaluating repeatability and avoiding elastic saturation near the surface source signatures can be made more consistent thus increasing the resolution of stacked data for 2 d 3 d and 4 d seismic surveys

morphotectonic segmentation and spatial variability of neotectonic activity along the narmada son fault western india remote sensing and gis analysis abstract morphotectonic analysis of landscape using remote sensing and gis is an effective way of deducing the pattern and spatial variation of neotectonic activity along poorly investigated active faults in this paper we evaluate the neotectonic activity along a part of the seismically active but poorly understood narmada son fault nsf a more than 1000 km long ene wsw trending fault transecting through the central part of the indian plate the nsf in the study area is geomorphologically expressed as an ene wsw trending line of north facing scarps that delimit the rugged mountainous topography of the uplands to the south and the alluvial basin to the north which prominently slope away from the scarps the scarps are developed in the south dipping basaltic flows belonging to the deccan trap formation of the late cretaceous eocene and continue westward into tertiary rocks and further as a paleobank of the narmada river field studies have revealed that the nsf in the study area is divisible into four morphotectonic segments i to iv which is attributed to the tilakwada karjan madhumati and rajpardi faults cutting across the nsf we characterize the neotectonic activity of the segments through dem analysis using geomorphic indices which include the mountain front sinuosity hypsometric curves hypsometric integral asymmetry factor stream length gradient index and channel sinuosity interpretations of morphometric data are well supported by field data both the entire length of the nsf and the cross faults are found to be neotectonically active we demonstrate that segment ii has undergone the highest intensity of neotectonic activity followed by segments iii i and iv this is corroborated by the highest elevation of scarps and the alluvial deposits the deepest incision 40 m depth and steep northward slope of the alluvial plain in segment ii we infer that the nsf is characterized by differential uplift in recent past which agrees with the high angle reverse faulting with oblique slip movements along the cross faults

spatial analysis of stream length gradient sl index for detecting hillslope processes a case of the gallego river headwaters central pyrenees spain abstract a morphometric analysis of drainage networks and relief using geomorphic indices and geostatistical analyses of topographical data are useful tools for discussing the morphoevolution of a given area among the geomorphic indices the stream length gradient sl index represents a practical tool to highlight anomalous changes in river gradients perturbations of sl are usually indicative of 1 differences in the resistance of outcropping lithological units to erosion 2 sub surface processes such as active faulting and 3 slope failures that directly reach the stream channels particularly in small catchments in this work the sl index was calculated for the upstream sector of the gallego river basin in the central spanish pyrenees to test its accuracy and sensitivity for detecting the imprints of different surface processes a geostatistical procedure is proposed to obtain sl index maps through the interpolation and filtering of the values estimated along the drainage network this method allows computing of sl validation and assessing of its spatial distribution with robust statistical accuracy and objectively defining the anomalies in sl the anomalies in the sl map of the study area which coincide with knickpoints and knickzones were analyzed in detail the results indicate 1 perturbation in the drainage network caused by differences in the resistance to erosion of outcropping lithological units and 2 hillslopes affected by large landslides earth flows and rock falls directly reaching the stream bed this study indicates that the sl index has strong potential to solve geomorphological problems in different geological settings especially in detecting the role of active large scale features that influence landscape evolution

thrust related river terrace development in relation to the 1999 chi chi earthquake rupture western foothills central taiwan abstract the 21 september 1999 earthquake mw 7 6 produced a surface rupture that extended for 100 km in a general north south direction in front of the western foothills central taiwan the study area located in a segment of the fold thrust belt of central taiwan provides an important natural laboratory to study the relationship between active thrust deformation and fluvial terrace development we recognize from west to east three subparallel thrusts the sanyi houli and shihkang faults in the northern part of the earthquake disaster area the 1999 earthquake rupture occurred only along the shihkang fault whereas the other two faults were inactive along the tachia river in the hanging wall of the shihkang fault eight well developed terrace levels are observed and can be subdivided into lateritic lt5 lt1 and non lateritic terraces ft3 ft1 five levels of lateritic terrace lt5 lt1 are located in the hanging wall of the houli fault and a lateritic terrace lt5 is present in the hanging wall of the sanyi fault stratigraphic and elevation correlations between these well developed fluvial terraces in relationship to nearby geologic structures show that the sanyi fault is the oldest structure lateritic terraces of at least 10 000 yr bp for example overlie the sanyi fault but correlative terraces associated with the houli fault are offset these types of terrace correlations allow us to define the progressive development of the thrust system within the western foothills

active tectonics of ne gujarat india by morphometric and morphostructural studies of vatrak river basin abstract landscape owes its shape to the combination of tectonic and climatic forces differential displacement of land by tectonic processes changes the elevation of earth s surface locally and in turn affects the rate of geomorphic processes which are altitude dependent the tectonic and geomorphic processes are very tightly coupled and their results are intertwined to extract the tectonic signal the numerical modelling of the landscape of the vatrak river basin part of which falls in the northern part of the gujarat alluvial plains of western india has been undertaken applying morphometric and morphostructural approach the study helped in understanding the role of tectonic elements in the evolution of the basin demarcation of geomorphic indicators of active tectonics which include the analyses of asymmetry factor valley floor ratio gradient basin elongation ratio long profile and related parameters pseudo hypsometric integral drainage basin asymmetry drainage pattern analysis and azimuthal distribution of stream channels have been performed for each drainage network and associated basin the morphological field evidence of tectonics combined with the results of morphometric analysis has been used to obtain information about the orientation of tectonic elements and the possible reconstruction of their activity in recent times the analyses indicate eastward tilting of the drainage systems strong asymmetry in some reaches pronounced elongation of certain tributaries long profiles indicating base level lowering poor organisation of the hydrographic network and close alignment between lower order streams and active faults all these analyses point towards the active tectonism in the area data obtained through the statistical analysis of preferred stream orientations confirm that the old tectonic directions markedly influenced the drainage network development of the older order streams whereas streams of lower order which preferentially follow the n s and ne sw directions suggest that these tectonic trends were active until very recent times

recent fold growth and drainage development the janauri and chandigarh anticlines in the siwalik foothills northwest india the active growth of a fault and thrust belt in frontal zones of himalaya is a prominent topographical feature extending 2500 km from assam to pakistan in this paper kinematical analysis of frontal anticlines and spatial mapping of active faults based on geomorphological features such as drainage pattern development fault scarps and uplifted quaternary alluvial fans are presented we analyse the geomorphic and hydrographic expressions of the chandigarh and the janauri active anticlines in the nw india siwaliks to investigate the morphological scenario during the folding process we used spatial imagery geomorphometric parameters extracted from digital elevation models and fieldwork folding between the beas and sutlej rivers gives clear geomorphological evidence of recent fold growth presumably driven by movements of blind thrust faults structural style within the janauri and chandigarh anticlines is highly variable fault propagation folds pop up structures and transfer faults the approach presented here involves analysis of topography and drainage incision of selected landforms to detect growth of active anticlines and transfer faults landforms that indicate active folding above a southwest dipping frontal thrust and a northeast dipping back thrust are described along strike differences in ridge morphology are measured to describe the interaction of river channel patterns with folds and thrust faults and to define history of anticline growth the evolution of the apparently continuous janauri ridge has occurred by the coalescence of independent segments growing towards each other by contrast systematic drainage basin asymmetry shows that the chandigarh anticline ridge has propagated laterally from nw to se

repeatability issues of 3 d vsp data increased repeatability is recognized as one major issue for improving the time lapse seismic technology as a reservoir management tool a 3 d vertical seismic profiling vsp data set acquired over a period of two days is used to analyze how repeatable a permanent installed geophone array can be and how repeatability changes with inaccuracies in source positioning it is found that for a frequency range between 3 5 and 50 hz the difference root mean square rms level between two recorded traces belonging to two different shots is about 8 this fact shows that there is a potential for acquiring very accurate time lapse seismic data by using a permanently installed downhole geophone array repeatability variation with increasing shot separation distances is analyzed showing a rapid decrease in repeatability as the accuracy of the positioning of the repeat survey decreases horizontal geophone components show approximately the same degree of repeatability compared to the vertical component but horizontal geophone data is slightly more sensitive to positioning errors the results show that repeated 3 d vsp surveys preferably using permanently installed geophone arrays might be an efficient tool for detailed and precise monitoring of fluid and pressure changes within a hydrocarbon reservoir

repeatability of multimode rayleigh wave dispersion studies rayleigh wave dispersion is used to study the near surface elastic properties of a thick lacustrine clay to approximately 10 m depth ten repeated sets of rayleigh dispersion curves were obtained through late spring to early fall a variety of methodologies were used to extract the dispersion curves but a modified frequency ray parameter f p method most successfully yields dispersion curves for the first three rayleigh modes the rayleigh wave velocities varied from 100 to 350 m s with frequency over the band from 75 to 10 hz over this band these velocities did not measurably vary during the study period the observed phase velocity curves were inverted with p wave and density values obtained from shallow coring to obtain the shear wave velocity structure at the site down to 14 m this case study highlights the robust repeatable nature of surface wave dispersion methods when care is taken in the acquisition of field data

known and suggested quaternary faulting in the midcontinent united states abstract the midcontinent united states between the appalachian and rocky mountains contains 40 known faults or other potentially tectonic features for which published geologic information shows or suggests quaternary tectonic faulting we report results of a systematic evaluation of published and other publicly available geologic evidence of quaternary faulting these results benefit seismic hazard assessments by 1 providing some constraints on the recurrence intervals and magnitudes of large prehistoric earthquakes and 2 identifying features that warrant additional study for some features suggested quaternary tectonic faulting has been disproved whereas for others the suggested faulting remains questionable of the 40 features nine have clear geologic evidence of quaternary tectonic faulting associated with prehistoric earthquakes and another six features have evidence of nontectonic origins an additional 12 faults uplifts or historical seismic zones lack reported paleoseismological evidence of large quaternary earthquakes the remaining 13 features require further paleoseismological study to determine if they have had quaternary earthquakes that were larger than any known from local historical records seven of these 13 features are in or near urbanized areas where their study could affect urban hazard estimates these seven are 1 the belt of normal faults that rings the gulf of mexico from florida to texas 2 the northeast ohio seismic zone 3 the valmont and 4 goodpasture faults of colorado 5 the champlain lowlands normal faults of new york state and vermont and 6 the lexington and 7 kentucky river fault systems of eastern kentucky

implications of shearing on drainage network development in achankovil shear zone south india insights from dem based geomorphic indices and longitudinal profile analysis the achankovil shear zone aksz in the southern granulite terrain separates the trivandrum block from the madurai block various geomorphic indices and longitudinal profiles of the river systems in the aksz viz achankovil river basin arb and kallada river basin krb were derived from srtm dem to decipher the influence of shearing and deformation on the regional drainage evolution although hypsometric analysis of the basins implies old stage of geomorphic evolution horizontal shifts in the channel plan form are restricted except in the tertiary sediments suggesting the structural controls over the drainage organization which are also supported by the high topographic sinuosity the transverse topographic symmetry t vectors indicate a southwesterly migration for the upstream channel segments of both arb and krb while the northwesterly migration of the downstream courses can be correlated with the dextral shearing of the aksz even though the shear zone is considered to be the block boundary between the charnockite of madurai and khondalite of trivandrum blocks the moderate to low profile concavity values are probably the result of suppressing the effect of the block boundary interactions by shearing and denudation the study proposes a model for evolution of drainage network in the aksz where the mainstream of the basins was initially developed along ne sw direction and later the upstream and midstream segments were reoriented to the nw se trend as a result of intense shearing overall the present study emphasizes the significance of geomorphic indices and longitudinal profile analysis to understand the role of shearing and deformation on drainage evolution in transcrustal shear zones

application of morphometry in neotectonic studies at the eastern edge of the parana basin santa catarina state brazil article i nfo the neotectonic evolution of the eastern edge of the parana basin in the santa catarina state brazil was investi gated using field data and detailed morphometric analysis along an east west section analysis included gener ation of maps of isobase hydraulic gradients hypsometry incision of drainage basins drainage asymmetry and anomalous morphological features all these maps generated results that agreed with field data and helped define recent faults in directions close to n s and e w both probably reactivated faults of the parana basin and the basement geomorphological features identified in topographic maps possibly related to neotectonism have a close agreement with our observations in the field the asymmetry of basins as analysed by the t index method proved to be compatible with the influence of a e w compressive tectonic regime and showed a move ment from w to e application of the hypsometric integral technique helped establish a correlation between the younger basins with structures trending n s 30 the n s faults were related to a compressional stress field shmax close to e wa nd shmin stress minimum around n s thereby establishing a tectonic context of structures developed in a transpressive regime the compressional field was caused by the subduction of the nazca tectonic plate below the south american plate whereas the transcurrent component exploited pre existent e w structures when the atlantic ocean was opening

tectonic controls of the north anatolian fault system nafs on the geomorphic evolution of the alluvial fans and fan catchments in erzincan pull apart basin turkey abstract the erzincan pull apart basin is located in the eastern section of the north anatolian fault system nafs the tectonic evolution of this basin is mostly controlled by strike slip master faults of the nafs this study examines the topography structure relationships in an effort to evaluate the tectonic signatures in the landscape paying special attention to recent tectonic activity in the study the main focus is on the tectonic controls of the nafs on the geomorphic evolution of alluvial fans and fan catchments in the erzincan pull apart basin the observations of the amount of tilting of the alluvial fans and its relation with morphometric asymmetry factor af hypsometric integral hi fractal analysis of drainage networks d properties of the fan catchments provide valuable information about the tectonic evolution of the basin area the results of the analyses showed that the alluvial fan and fan catchment morphology in the pull apart basin are mainly controlled by the ongoing tectonic activity of the nafs the fault system in the basin has controlled the accommodation space by causing differential subsidence of the basin and aggradation processes by causing channel migration channel incision and tilting the alluvial fans

geomorphic response to neotectonic instability in the deccan volcanic province shetrunji river western india insights from quantitative geomorphology abstract the saurashtra peninsula a deccan trap terrain in western india lacks the studies that document on land information of tectonically active faults in the present paper the tectonogeomorphology of the shetrunji river basin is investigated to identify the neotectonic signatures of the buried structural element by detailed analyses of the landforms and drainage pattern using quantitative geomorphic analysis morphostructural studies and gradient length analysis gla along with field investigation the basin has been divided into three segments based on channel orientation a segment 1 upper reach oriented in ne sw direction b segment 2 middle reach oriented in an e w direction and c segment 3 lower reach oriented in nw se direction the tectono geomorphic analysis suggests the neotectonic deformation is mainly demonstrated by the ne sw oriented girnar fault gf in segment 1 and e w oriented shetrunji fault sf in segment 2 the segment 3 interestingly shows least or no tectonic deformation signatures for the first time we report the geomorphic evidence of the two main faults 1 the girnar fault gf a left lateral strike slip fault and 2 the shetrunji fault zone sfz a right lateral strike slip fault the interplay between drainage pattern and buried structures are observed in the form of offset channel offset ridges deflection in stream and linear valleys the sfz is characterized by an anastomosing drainage pattern offsetting deflection of streams and development of linear valleys in zone which is 52 km in length and 2 km wide the sl index and ksn show high values along the fault zone which is also supported by the presence of incised river channel entrenched mender and incised ravine surfaces the study reveals the prevalent neotectonic activity in the shetrunji river basin along with the gf and the sfz the findings are consistent with the geomorphic structural setup of the region and coincide with the historical as well as current seismicity distribution

gis based approach for the measurement of variability in tectonomorphic signatures using dem s data a case study from the habo dome in the kachchh area india the kachchh region of western india is located in a plate interior region but falls under one of the highest seismic zones of india having very active crustal deformation and erosion the drainage system as well as the geomorphic evolution of the region under a semi arid climate zone with high to very high strength of rocks in areas with high relief is dominantly controlled by the seismic instability associated with continual tectonics in the present paper we have analysed a block close to the epicentre of the 2001 bhuj earthquake to understand the role of relative active tectonics in the evolution of domal landscape morphology shuttle radar topographic mission digital elevation model data were used to extract drainage network in the gis platform and evaluate active tectonics using different geomorphic indices of the habo hill the second largest domal structure situated in northern hill range of the kachchh region the average cumulative weightage of different geomorphic indices provides a quantitative tool index of relative active tectonics irat which shows significant variations in and around the habo dome activation of earlier lineaments and generation of new lineaments controlled the morphometric evolution of the fault bound block of the region to form the habo dome the undulating topography in addition to the domal shape of the study area resulted from the differential movements along several active transverse faults striking ne sw n s and nw se and the regional faults striking e w the kachchh mainland fault the kas fault and the jikadi fault stress propagations from the himalayan range in the northeast and suleiman range in the northwest are identified to be the causative factors for active tectonics and drainage anomalies in the area

tilting neotectonics of the guadiamar drainage basin sw spain the guadiamar river ows from the southern iberian massif to the guadalquivir foreland basin sw spain its drainage basin displays asymmetries in the stream network the arrangement of alluvial terraces and the con guration of the trunk river valley the stream network asymmetry was studied using morphometric measures of transverse topographic sym metry asymmetry factor and drainage basin shape the alluvial terraces were studied through the lithologic logs of more than a hundred boreholes and eld mapping the morphometric methods demonstrate a regional tectonic tilting toward the sse causing both the migration of the guadiamar river toward the east and the migration of the guadiamar tributaries toward the southwest as a consequence of the guadiamar river migration an asymmetric valley developed with a steep eastern margin caused by river dissection and a gentle western margin where the main alluvial deposits are found the ages obtained using the 14c analysis of samples from several alluvial deposits show that the river migration and thus tilting has occurred during the holocene as well as earlier in the quaternary this interpretation revises the guadiamar longitudinal fault assumed by previous studies copyright 2003 john wiley sons ltd

time lapse seismic reservoir monitoring time lapse seismic reservoir monitoring has advanced rapidly over the past decade there are currently about 75 active projects worldwide and more than 100 cumulative projects in the past decade or so the present total annual expenditures on 4 d seismic projects are on the order of 50 100 million us this currently represents a much smaller market than 3 d seismic but the use of 4 d seismic has grown exponentially over the past decade and is expected to continue to do so

the use of the stream length gradient index in morphotectonic analysis of small catchments a case study from central italy abstract the aim of this work is to test an integrated quantitative geomorphic approach based on stream length gradient index sl index analysis within the small catchment of the tarugo river in the northern marchean apennines central italy the tarugo river basin 92 km 2 wide strikes sw ne across the marchean ridge and the western sector of marchean piedmont the area is characterized by a series of nw se trending ne verging thrust folds affecting the meso cenozoic bedrock that pass upward from dominantly carbonate to dominantly terrigenous rocks the area investigated has been affected since the pliocene by extensional tectonics accompanying a regional uplift decreasing in rate north eastwards in this work the sl index analysis has been integrated with the spatial analysis of the amplitude of relief a r and compared to geological and geomorphological field data results of this work indicate that the sl index is a valid tool to detect the long wavelength structural effect on topography as well as the incipient local response to regional processes i e regional uplift that is often undetectable by other morphotectonic parameters in contrast the sl index analysis seems not be a valid tool for discriminating the local lithological influence from the tectonic one

tilting of active folds and drainage asymmetry on the manawatu anticlines new zealand a preliminary investigation the apparent southward tilting of five anticlines in the manawatu north island new zealand is investigated using two drainage basin analysis techniques the transverse topographic symmetry factor t and the asymmetry factor af the techniques are used to determine whether westward flowing trunk streams on the gentle western limbs of five anticlines are migrating southwards across their drainage basins concomitant with down tilting of the fold axes while results show potential for the techniques to be applied in such a tectonic setting our findings are inconclusive this could be due to the incipient nature of the folds c 0 5 ma in age and it would seem more appropriate to apply the techniques in concert with detailed field analyses of river migration patterns copyright 2008 john wiley sons ltd

feasibility of utilizing wavelet phase to map the co2 plume at the ketzin pilot site germany spectral decomposition is a powerful tool that can provide geological details dependent upon discrete frequencies complex spectral decomposition using inversion strategies differs from conventional spectral decomposition methods in that it produces not only frequency information but also wavelet phase information this method was applied to a time lapse three dimensional seismic dataset in order to test the feasibility of using wavelet phase changes to detect and map injected carbon dioxide within the reservoir at the ketzin carbon dioxide storage site germany simplified zero offset forward modelling was used to help verify the effectiveness of this technique and to better understand the wavelet phase response from the highly heterogeneous storage reservoir and carbon dioxide plume ambient noise and signal to noise ratios were calculated from the raw data to determine the extracted wavelet phase strong noise caused by rainfall and the assumed spatial distribution of sandstone channels in the reservoir could be correlated with phase anomalies qualitative and quantitative results indicate that the wavelet phase extracted by the complex spectral decomposition technique has great potential as a practical and feasible tool for carbon dioxide detection at the ketzin pilot site

feasibility of co2 plume detection using 4d seismic co2crc otway project case study part 2 detectability analysis abstracta key objective of stage 2 of the cooperative research centre for greenhouse gas technologies co2crc otway project is to explore the ability of the seismic reflection method to detect and monitor injection of a small amount of greenhouse gas into a saline formation development of a seismic monitoring program requires an understanding of expected time lapse tl seismic signals hence before such an injection experiment is undertaken we assessed the feasibility of seismic monitoring in a modeling study considering realistic gas distributions inferred from reservoir simulations we analyzed the influence of various factors injection volume time after injection and realizations of the reservoir flow model on the tl seismic signal however the applicability of seismic monitoring depends not only on the strength of the tl seismic signal but also on the noise level of the seismic data hence to estimate the detectability of gas in the subsurface we have developed a workflow that integrated

repeatability analysis of land time lapse seismic data co2crc otway pilot project case study time lapse seismics is the methodology of choice for remotely monitoring changes in oil gas reservoir depletion reservoir stimulation or co 2 sequestration due to good sensitivity and resolving power at depths up to several kilometres this method is now routinely applied offshore however the use of time lapse methodology onshore is relatively rare the main reason for this is the relatively high cost of commercial seismic acquisition on land a widespread belief of a relatively poor repeatability of land seismic data prevents rapid growth in the number of land time lapse surveys considering that co 2 sequestration on land is becoming a necessity there is a great need to evaluate the feasibility of time lapse seismics for monitoring therefore an understanding of the factors influencing repeatability of land seismics and evaluating limitations of the method is crucially important for its application in many co 2 sequestration projects we analyse several repeated 2d and 3d surveys acquired within the otway co2 sequestration pilot project operated by the cooperative research centre for greenhouse technologies co2crc in australia in order to determine the principal limitations of land time lapse seismic repeatability and investigate the influence of the main factors affecting it our findings are that the intrinsic signal to noise ratio s n signal to coherent and background noise levels and the normalized root meansquare nrms difference are controlled by the source strength and source type however the post stack s n ratio and corresponding nrms residuals are controlled mainly by the data fold for very high fold data the source strength and source type are less critical

a case history of time lapse 3d seismic surveys at cold lake alberta canada time lapse 3d seismic surveys were acquired across a bitumen field at cold lake alberta canada during a production cycle 1990 and a steam injection cycle 1992 of a thermal enhanced oil recovery eor program we observed changes in interval traveltime and amplitude distributions between the processed surveys we interpret the increased traveltimes observed over most of the injection survey to be a result of lowered interval velocities in the reservoir caused primarily by higher temperature and lower effective pressure reflection strength variations within the reservoir are present in each data set and change spatially between the surveys in general we interpret the amplitude anomalies seen only on the production survey to be caused by local free gas and the amplitude anomalies seen only on the injection survey which are close to the perforation depths to be caused by thin vertically restricted steamed zones

near surface fault detection using high resolution shear wave reflection seismics at the co2crc otway project site australia high resolution near surface shear wave reflection seismic measurements were carried out in november 2013 at the co2crc otway project site victoria australia with the aim to determine and if so where deeper faults reach the near subsurface from a previous p wave 3 d reflection seismic data set that was concentrated on a reservoir at 2 km depth we can only interpret faults up to 400 m below sea level for the future monitoring in the overburden of the co2 reservoir it is important to know whether and how the faults continue in the subsurface we prove that two regional fault zones do in fact reach the surface instead of dying out at depth individual first break signatures in the shot gathers along the profiles support this interpretation however this finding does not imply perforce communication between the reservoir and the surface in the framework of co2 injection the shear wave seismic sections image with high resolution better than 3 m vertically and complementary to existing p wave volumes different tectonic structures similar structures also outcrop on the southern coast of the otway basin both the seismic and the outcrops evidence the complex youngest structural history of the area

impact of tectonics on drainage network evolution of suru basin kargil n w himalaya jammu and kashmir india the main objective of this paper is to work out quantitative measurement of various geomorphic parameters as well as analysis of geomorphic landforms to study the tectonic character of suru basin morphometric analysis being widely used to assess the drainage characteristics of the river basins has also been found to be a useful tool to delineate tectonically active zones a number of parameters including the mountain front sinuosity asymmetry factor transverse topography symmetry hypsometry longitudinal profile and the shape parameters have been used the low mountain front sinuosity values 1 4 indicate that the tectonic forces dominate over erosive activity also the asymmetry factor 66 98 suggests that the right side of the basin has experienced uplift with the development of unpaired river terraces hypsometric integral 0 96 convex up hypsometric curve and the gps data of year 2011 2013 indicate that the relief of the basin is high relative to mean is in youthful stage and actively uplifting at the rate of 2 18 0 99 mm year the shape parameters further suggest that the suru river basin having lower elongation ratio is indicative of elongate shape of basin with tectonic forces outpacing the erosion power area altitude analysis of the suru river basin indicates that about 72 of the area of the basin is steeply to very steeply sloping and 28 area is moderately to gently sloping the area altitude indicates 72 area of basin could slide when there is slight shift in terms of tectonic disturbance in addition to the geomorphic indices the field investigations reveal tectonically unstable character exhibit a complex topography and varied quaternary sedimentation the major geomorphic landforms viz alluvial terraces alluvial fans debris cone scree and talus cone at the foothills are present throughout the valley with tectonic structures like micro folds back tilted beds deeply incised valleys faults and tectonic deposits ophiolites indicating that the tectonic activity has affected the basin the synergized results of geomorphometry field investigations and gps data indicate that the suru basin is tectonically active and uplifting

tectono geomorphic indices of the erin basin ne kashmir valley india abstract the present study aims to assess the tectonic activity in the erin basin ne kashmir on the basis of several relevant geomorphic indices and field observations we use digital elevation model srtm and survey of india soi topographic maps in gis environment to compute the geomorphic indices the indices i e convex hypsometric curve high hypsometric integral value h i 0 5 low basin elongation ratio eb 0 17 low mountain front sinuosity values s mf 1 08 average low valley floor width ratios vf 4 suggest that the area is tectonically active moreover prominent irregularities knickpoints knickzones along longitudinal profile of the erin river even in homogenous resistant lithology panjal trap and anomalous stream gradient index sl values reflect that the erin basin is dissected by two faults ef 1 and ef 2 with nnw sse and ssw nne trends respectively the results of this preliminary study further substantiate the recent gps studies which argue that the maximum strain is accumulating in the ne part of the kashmir himalaya

asymmetrical river valleys and their tectonic significance in the maxianshan area ne tibetan plateau abstract the geometry of river networks is particularly sensitive to active tectonic deformation morphotectonic analyses conducted using geomorphic indices and numerical models are useful methods with which to identify such deformation the northeastern ne margin of the tibetan plateau is characterized by active tectonics easily erodible bedrock and well developed valleys and is thus an ideal region for studying the effects of tectonics on the landscape evolution here we firstly identify the systemic asymmetrical valleys in the maxianshan area ne tibetan plateau to quantitatively analyze the asymmetrical characteristics of these valleys identified in the southern maxianshan 33 parallel streams were investigated by using two drainage basin analytical techniques namely the transverse topographic symmetry factor t and asymmetry factor af our results show that the mean t value is 0 14 magnitude and 319 08 direction and the majority of the af results are

multi stream order analyses in basin asymmetry a tool to discriminate the influence of neotectonics in fluvial landscape development madrid basin central spain morphometric analysis of the tajo drainage network using a dem was carried out in order to determine neotectonic influence on the development of the madrid basin since the pliocene statistical analysis of digitally derived transverse topographical drainage basin asymmetry t factor was used to infer directions of ground tilting a crustal block pattern was interpreted from a mean basin asymmetry vector field that was computed using a new approach based on a gridded running average of the raw vector field measurement of r factor for different order channels allows investigation of evolution rates of different order rivers and at the same time reveals possible factors controlling basin evolution the vector data show clear differences between high and low orders high order asymmetry is consistent with fluvial terrace distribution as it reflects channel migration and incision within the main valleys and shows a general trend toward a central basin axis running sw ne a sw ne trend is also defined by other morphographical approaches such as drainage density and relief analysis both approaches point toward the presence of two uplifted areas running sw ne and a subsided zone between them which is in agreement with previous crustal flexure models in contrast low order asymmetry shows a clear trend indicating eastward tilting which could be driven by recent changes in maximum principal stress direction and its influence on fault reactivations in general large rivers generating fluvial terraces are controlled by basement structure with positive and negative crustal flexures driving their migration direction and thus controlling the spatial distribution of terraces because the position of main streams is controlled by large tectonic lineaments that favor groundwater flow convergence on the other hand small tributaries have low capabilities to attain equilibrium and t factor values of low order basins may reflect more recent block tectonics due to variations in stress fields or may reflect local controls like lithology

the seismic signature of rain abstractrain has long been a problem for land seismic surveys in terms of its effect on the condition of the surface and near surface and also due to the seismic noise it creates when raindrops hit the ground i measured the seismic signature of rainfall using water dripped from height using a pipette and natural rain in winchester england over a three month period my results indicated that rain noise is concentrated at frequencies of greater than 80 hz with a detectable range of less than 1 m drops of water landing directly on a geophone result in events with amplitudes nearly 30 times larger than those landing next to the geophone items placed on the surface of the ground such as cables absorb the energy of the impact and reduce the level of the resulting seismic noise burying geophones results in attenuation of rain noise by between 7 7 and 8 6 db 0 1 m but given the effort required to bury geophones it is likely that data processing algorithms or the placement of vibration absorbent ma

drainage anomalies as indicators of soft linked deformation zones between neotectonic structural highs in the precordillera central andes of argentina abstract between 31 45 32 15 s the western piedmont of the ansilta block in the precordillera of argentina has been uplifted in quaternary times through folds blind faults and faulted blocks that form discrete and evident areas of neotectonic deformation structural highs in between subtle tectonic perturbations of the fluvial landforms drainage anomalies such as diverted and entrenched streams asymmetric basins incision anomalies convex upward longitudinal stream profiles dammed rivers and broom shaped patterns allow the recognition of areas of incipient deformation we combined the analyses of both the structural highs and the drainage anomalies areas to investigate the role of the latest as an expression of soft linkage areas in fault systems the structural highs would be interpreted as isolated features without the consideration of the drainage anomalies areas between them moreover linking the structural highs using the drainage anomalies reveals the extent of major quaternary deformation belts in their initial development stages

tectonic geomorphology of the easternmost extension of the gulf of corinth beotia central greece the easternmost sector of the gulf of corinth the beotia area in central greece is an area with active normal faults located between the two major rift structures of central greece the gulf of corinth and the north gulf of evia these active normal faults include wnw to e w and ne to ene trending faults affect the landscape and generate basin and range topography within the beotia we study four normal fault zones and drainage basin geometry in the easternmost sector of the gulf of corinth to document the impact of active tectonics on the landscape evolution fault and drainage geometry are investigated based on detailed field mapping and high resolution digital elevation models tectonic geomorphic analysis using several parameters of active tectonics provides information concerning the relative tectonic activity and fault growth in order to detect areas of lateral stream migration that could indicate recent tectonic activity the transverse topographic symmetry factor and the asymmetry factor are used to analyse drainage basin geometry in six large drainage basins and a drainage domain covering the study area our results show that vertical motions and tilting associated with normal faulting influence the drainage geometry and its development values of stream gradient indices sl are relatively high close to the fault traces of the studied fault zones suggesting high activity mountain front sinuosity smf mean values along the fault zones ranges from 1 08 to 1 26 valley floor width to valley height ratios vf mean values along the studied fault zones range between 0 5 and 1 6 drainage basin shape bs mean values along the fault zones range from 1 08 to 3 54 all these geomorphic parameters and geomorphological data suggest that the analyzed normal faults are highly active lateral fault growth was likely produced by primarily eastward propagation with the wnw to e w trending faults being the relatively more active structures

inverted fluvial features in the aeolis zephyria plana western medusae fossae formation mars evidence for post formation modification 1 the aeolis and zephyria plana contain the western most portion of the medusae fossae formation mff an enigmatic and extensive light toned deposit located in the martian equatorial region and dated from the hesperian to amazonian epochs this area hosts a large population of sinuous ridges srs interpreted as inverted fluvial features formed by precipitation indurated by chemical cementation buried by subsequent deposition and finally exhumed this interpretation of srs as uniformly fluvial represents a modification to an earlier hypothesis for one particular sr of possible glaciofluvial i e esker formation these srs provide a tool to investigate the degree and character of post fluvial modification processes in this region we combined digital terrain models made from context camera ctx and high resolution imaging science experiment hirise stereo image pairs with individual data points from the mars orbiter laser altimeter mola to estimate relief cross sectional profiles longitudinal profiles and slope directions of selected srs longitudinal profiles of several srs display undulations with amplitudes of up to order 100 m while some of the lower amplitude undulations may be due to differential erosion undulations having amplitudes in excess of sr relief require alternative explanations our combined morphologic and topographic analysis suggests that multiple post flow processes including compaction of the deposits and tectonic displacements have modified the original sr profiles specification of the type s and magnitudes of these modification processes will contribute to understanding both the potential of post flow modification of fluvial profiles elsewhere on mars as well as the nature and properties of the mff

analysis of drainage basin symmetry as a rapid technique to identify areas of possible quaternary tilt block tectonics an example from the mississippi embayment there is a coincidence of seismicity and major river valleys in the southwestern mississippi embayment that suggests control of the drainage pattern by northwest trending faults pleistocene river terraces reveal a strong southwestward preferred river migration in this region that may be a result of fault block tilting a rapid new technique of drainage basin analysis is herein presented that quantifies transverse topographic basin symmetry these data permit discrimination of random stream migrations and regionally preferred stream migrations and identify the direction of maximum migration if bedrock dip can be shown to be a negligible influence on stream migration then the direction of regionally preferred migration implies a period of ground tilting in that direction drainage basin asymmetry vectors bearing and degree of asymmetry calculated from transverse topographic profiles of 271 4 km basin segments in the study area suggest preferred stream migration in response to west southwest ward ground tilting bearing 259 the eastward regional dip of bed rock horizons only locally influences migration river terrace distributions reveal a chronology of stream migration episodes southwestward migration in the ouachita saline and arkansas river basins occurred during early to middle pleistocene time in the southwestern mississippi embayment a wisconsin early holocene southwestward migration episode is evidenced along southeast flowing reaches of the ouachita and arkansas rivers but not along the southeast flowing reach of the intervening saline river suggesting that these rivers overlie separate northwest trending tilt blocks although this technique does not provide direct evidence of ground tilting it provides a quick look method of identifying possible tilting elements in neotectonic regions using only topographic maps this technique is of greatest utility where active faults are concealed or poorly exposed such as in the mississippi embayment

a tectonically triggered late holocene seismite in the southern amazonian lowlands brazil abstract definitive criteria for identifying the triggers of soft sediment deformation structures ssdss from sedimentary deposits are still under construction in this work we aimed to contribute to advancing this issue describing the sedimentological characteristics of an interval of ssdss formed in a region of the amazonian lowlands having numerous morphostructural evidences of neotectonic reactivation the deformed interval is 1 5 m thick and consists of load and flame structures interbedded with massive beds sandwiched between well stratified deposits of a fluvial sandy channel succession with a radiocarbon age of 1301 1382 cal yr bp the ssdss are intercepted by numerous small scale normal graded faults the most interesting is that these faults display segmented nw se trending planes that propagate upward after horizontal displacements of a few millimeters processes intrinsic to channel dynamics could not justify this fault morphology which is related to recurrent short lived seismic perturbations with intervening sedimentation following a main tremor a relation to fault reactivation is proposed with basis on the fault trend compatible with the regional structural pattern and the numerous morphostructural anomalies verified in the study area including trellis and sub trellis drainage rectangular and to a less extent annular channels anomalously enlarged channels orthogonal channels and valleys channel captures sudden changes in channel morphology moderate to high basin asymmetry factor af between 10 and 27 moderate to high transverse topography symmetry factor t 0 3 0 5 and anomalous longitudinal river profiles with concavity values 11 to 30 indicative of rivers in process of adjustments the morphology of the fault graded beds described herein might constitute a feature of relevance for identifying seismites in other fluvial deposits

seismic inversion tracks in situ combustion a case study from balol oil field india in situ combustion is one of the approaches used for secondary recovery of heavy oil in which time lapse seismic data might be used to track the production process we have analyzed three time lapse seismic surveys carried out at a time interval of one year during pre and postcombustion phases of in situ combustion at the balol field in india interpretation of these land time lapse data using standard seismic amplitude differences in terms of reservoir changes during production and injection can be erroneous the balol data in particular lacked calibration and had poor repeatability we have addressed these issues by demonstrating the applicability of independent prestack inversion of baseline and monitor surveys to derive elastic attributes that help to produce clearer images of fluid movement independent estimates of wavelets from the baseline and two monitor surveys were used in prestack inversion to estimate acoustic impedance shear impedance and poisson s ratio the results show unexpected movement of the thermal front away from the injection wells toward the north and northwest of the injection wells farther from the production wells these results have been confirmed by well production data from the field north and northwest of balol

morphotectonic analysis and gnss observations for assessment of relative tectonic activity in alaknanda basin of garhwal himalaya india abstract alaknanda basin in the garhwal himalaya india is a tectonically active region owing to ongoing crustal deformation erosion and depositional processes active in the region active tectonics in this region have greatly affected the drainage system and geomorphic expression of topography and provide an ideal natural set up to investigate the influence of tectonic activity resulting from the india eurasia collision we evaluated active tectonics by using high resolution digital elevation model dem based on eight geomorphic indices stream length gradient index valley floor width to height ratio hypsometric integral drainage basin asymmetry transverse topography symmetry factor mountain front sinousity index bifurcation ratio and basin shape index and seismicity in eight subbasins of alaknanda basin the integrated product relative tectonic activity index tai map was classified into three classes such as highly active with values ranging up to 2 0 moderately active with values ranging from 2 0 to 2 25 and less active with values 2 25 further the results were compared with relatively high crustal movement rate of 41 10 mm y computed through high precession global navigation satellite system gnss based continuous operating reference station cors data thus we concluded that this new quantitative approach can be used for better characterization and assessment of active seismotectonic regions of the himalaya and elsewhere

drainage evolution in a rifted basin corinth graben greece abstract intrabasinal basement highs and transfer faults distance from source and the underlying geology influence the drainage pattern and the evolution of the 41 river basins in the northern peloponnesus these rivers were classified as antecedent 10 multistory 17 re established 5 and juvenile 9 drainage types antecedent drainage is when a river has maintained its original direction of flow across later tectonic topography multistory drainage consists of a re established drainage and of a reverse drainage reverse drainage when flow direction along part of a river is reversed consists of two opposing drainage components a misfit and a reverse element the area between these two elements termed wind gap is a dry valley re established drainage is when a reverse element returns to its original flow direction juvenile drainage consists of small incising and headward eroding streams the sediments that the rivers flow across soft uncohesive marls or coarse grained deposits and pre neogene basement with limestones river power strong close to the source or weak far from the source presence or absence of transfer faults and tilted blocks due to the activity of synthetic and antithetic faults all influence whether an antecedent drainage will remain unchanged or will be changed to a reverse drainage when transfer faults cross cut the area of a wind gap and the underlying sediments were soft uncohesive marls reverse drainage changed to a re established drainage in other cases where transfer faults were absent and underlying deposits were coarse grained sediments or limestones in the area of the wind gap then reverse drainage remained unchanged

relative tectonic activity assessment and kinematic analysis of the north bozgush fault zone nw iran abstract nw iran is among the most interesting and complex areas within arabian eurasia collision zone historical and instrumental earthquake records in this region indicate that active faults have the potential to produce serious seismic hazards in the future the north bozgush fault zone an anastomosing fault zone consists of several parallel and sub parallel faults which have developed in a right lateral strike slip system with a reverse component our structural analysis shows that faulting occurs along a strong dominant compressional strike slip regime and is predominantly related to nw se shortening along the zone this paper represents an analysis of the morphometric indices to depict the tectonic activity of the northern part of the bozgush mountains an area with a typical tectono morphology the result of the morphometric analysis shows that relative tectonic activity along the north bozgush fault zone decreases significantly from west to east measured uplift rates show that the uplift rate is higher than 0 5 mm yr in the western and central parts and decreases in the eastern part to between 0 5 and 0 05 mm yr the structural and morphometric data are indicative of the relation between the north bozgush fault zone and the tabriz fault zone during quaternary time

burying receivers for improved time lapse seismic repeatability co2crc otway field experiment 4d seismic is widely used to remotely monitor fluid movement in subsurface reservoirs this technique is especially effective offshore where high survey repeatability can be achieved it comes as no surprise that the first 4d seismic that successfully monitored the co2 sequestration process was recorded offshore in the sleipner field north sea in the case of land projects poor repeatability of the land seismic data due to low s n ratio often obscures the time lapse seismic signal hence for a successful on shore monitoring program improving seismic repeatability is essential stage 2 of the co2crc otway project involves an injection of a small amount around 15 000 tonnes of co2 ch4 gas mixture into a saline aquifer at a depth of approximately 1 5 km previous studies at this site showed that seismic repeatability is relatively low due to variations in weather conditions near surface geology and farming activities in order to improve time lapse seismic monitoring capabilities a permanent receiver array can be utilised to improve signal to noise ratio and hence repeatability a small scale trial of such an array was conducted at the otway site in june 2012 a set of 25 geophones was installed in 3mdeep boreholes in parallel to the same number of surface geophones in addition four geophones were placed into boreholes of 1 12m depth in order to assess the gain in the signal to noise ratio and repeatability both active and passive seismic surveys were carried out the surveys were conducted in relatively poor weather conditions with rain strong wind and thunderstorms with such an amplified background noise level we found that the noise level for buried geophones is on average 20 db lower compared to the surface geophones the levels of repeatability for borehole geophones estimated around direct wave reflected wave and ground roll are twice as high as for the surface geophones both borehole and surface geophones produce the best repeatability in the 30 90 hz

morphotectonic analysis of aripal basin in the north western himalayas india an evaluation of tectonics derived from geomorphic indices abstract himalayan river basins are exposed to continuous erosion and deformational processes the main goal of this paper is to characterize the tectonic activity as it acts as a controlling factor in the development of landforms in the tectonically active terrains research was carried out in the aripal basin which lies to the south east of kashmir valley one of the right bank tributary of river jhelum the geomorphic indices and morphometric parameters are determined using advanced spaceborne thermal reflection and emission radiometer aster 30 m digital elevation model the low mountain front sinuosity smf 1 3 s type hypsometric curve with high hypsometric integral hi 0 35 low valley floor width to valley height ratios vf

strike slip faulting topographic growth and block movements as deduced from drainage anomalies the yesilirmak river basin northern turkey abstract this study aims to understand the various effects of known tectonism on a fluvial network and to interpret the tectonic deformations using described and analysed systematic anomalies in the drainage basin of the yesilirmak river in northern turkey at countermarch this region which is divided into several faulted wedges by right lateral strike slip faulting of the north anatolian fault zone and its individual splays has experienced several moderate to large earthquakes with high amounts of surface ruptures during the historical and instrumental periods the yesilirmak river basin includes several geomorphic imprints of such widespread and frequent strike slip deformations offsets between 750 m and 19 km aligned drainages and linear valleys 170 km are expected geomorphic and tectonic responses to strike slip faulting in the fluvial system we used such indicators to determine the long term effects of strike slip faulting in the yesilirmak river drainage network the measured stream offsets represent decreasing values toward southern splay faults consistent with published geodetic data for the region however some other large scale geomorphic anomalies extracted from the drainage network are not explainable by only strike slip tectonics compressional structures i e anticlines synclines in the region are responsible for such large scale drainage diversions 20 24 km along the river courses although these diversions the north anatolian fault zone is the main driving force shaping present geomorphology on a regional scale the sungurlu ezinepazari fault also plays a critical role in landscape evolution their activities and associated block movements have resulted with tilting processes on the other hand the entire fluvial network should be modified by the sea level changes of the black sea particularly in the late quaternary

middle to late holocene paleochannels and migration of the palar river tamil nadu implications of neotectonic activity abstract geomorphic tectonic and sedimentary investigations have been carried out to understand the landscape evolution of the palar river basin southern peninsular india for this purpose satellite data interpretations coupled with field investigations fluvial architecture and optically stimulated luminescence osl dating methods were adopted to infer climatic variations and neotectonic deformation that took place during the mid to late holocene period several paleochannels have been identified in the northern part of the present day palar river the distribution pattern of the palar paleochannels and its present course indicate its migration towards the south leaving behind the old palar river streams as paleochannels significant changes in the morphological characteristics channel width and river pattern in the successive paleochannels reveal evidences of channel movement by avulsion largely controlled by reactivation of pre existing lineaments and intensified ne monsoon based on osl ages two major phases of migration have been identified that occurred between 4 83 ka to 1 88 ka first phase occurred between 3 59 ka to 3 26 ka due to intensified monsoon accompanied with small scale neotectonic activity the second phase took place between 2 42 ka to 1 88 ka which occurred probably due to the rapid upstream avulsion this rapid avulsion is due to the close proximity of mpa and the reactivation of the pre existing lineaments moreover the present palar river basin exhibits evidences of neotectonic activity such as soft sediment deformation structures anomalous drainage deflections and reactivation of lineaments and faults further indicating that the palar river is still draining a tectonically active region thus neotctonics and fluctuations in the intensity of monsoon are largely responsible for sculpting the present landscape

assessment of 4d seismic repeatability and co2 detection limits using a sparse permanent land array at the aquistore co2 storage site abstracttwo 3d time lapse seismic surveys were acquired in 2012 and 2013 at the aquistore co2 storage site prior to the start of co2 injection using these surveys we determined the background time lapse noise at the site and assessed the feasibility of using a sparse areal permanent receiver array as a monitoring tool applying a standard processing sequence to these data we adequately imaged the reservoir at 3150 3350 m depth evaluation of the impact of each processing step on the repeatability revealed a general monotonic increase in similarity between the data sets as a function of processing the prestack processing sequence reduced the normalized root mean squared difference nrms from 1 13 between the raw stacks to 0 13 after poststack time migration the postmigration cross equalization sequence further reduced the global nrms to 0 07 a simulation of the changes in seismic response due to a range of co2 injection scenarios suggested that co2 was detectable within the reservoir at the aquistor

reconstructed seismic and tsunami scenarios of the 1905 calabria earthquake se tyrrhenian sea as a tool for geohazard assessment abstract italy is one of the most seismically active regions in the central mediterranean and one of the countries with the longest record of historical earthquakes in the world over the last decades the scientific community has recognised the value of historical data when used to constrain modelling tools in hazard analyses this is the case of the destructive 1905 calabria south italy earthquake followed by a tsunami and by many secondary effects on the environment observed both inland and offshore recently acquired geophysical data allowed to identify an active normal fault named sant eufemia fault located nearshore in the sant eufemia gulf se tyrrhenian sea considered the most probable seismogenic source of the 1905 earthquake and capable to trigger future events in this paper we perform a scenario based deterministic analysis for an earthquake resulting from the rupture of the sant eufemia fault sef and a preliminary potential risk analysis after defining source parameters compatible with the 1905 earthquake ca 40 km fault length and ca 2 3 m slip mw 6 9 kf analysis and tsunami simulations are carried out and modelling results are compared against historical available data the obtained results allow one to border areas in central calabria that are most exposed to geohazard deriving from the analyzed fault some of these areas happen to be zones with intense economic touristic and urban development which calls for the need to integrate the ongoing development plans with adequate programs of risk mitigation and prevention

seismic monitoring of the duri steamflood application to reservoir management the duri steamflood operated by caltex pacific indonesia has employed time lapse seismic monitoring technology as an important component of its reservoir management process since the completion of a successful pilot study in 1995 see seismic monitoring of the duri steamflood a pilot and feasibility case study in this issue of tle time lapse seismic surveys have been shot in six areas of varying steamflood maturity and new surveys will be acquired as undeveloped areas are placed on steam injection

assessment of morphometric parameters for the development of relative active tectonic index and its significant for seismic hazard study an integrated geoinformatic approach earthquake is a geological natural hazard which is shaking of earth s surface due to seismic activity the himalayan region and quaternary geological surface of indian sub continent had experienced several earthquakes in the recent geological period due to reactivation of existing faults surface drainage system and its morphometric characteristics are controlled by subsurface geo structural features and active tectonic process which have greater impact on seismic activity thus the present study focuses on the analysis of morphometric parameters for the development of relative active tectonic index rati and its significant for seismic hazard assessment using geoinformatics the different morphometric parameters have been analyzed and geospatial databases have been generated the rati has been estimated by considering higher priority tectonic influencing parameters based on principal component analysis pca methods and the output has also been integrated with thematic and seismological databases to understand its significance for seismotectonic activity the result shows that the very high and high relative active tectonic index are observed in greater and lesser himalayan sequence where frequency of earthquake and its magnitudes are also high the anomalous nature of drainage network compressed meander in youthful stage presence of high resistance rocks structural control on drainage network relief steepness and v shaped narrow valley are the indicator of active tectonics and seismic activity in this region even though the foothills micro basin shows moderate or low relative active tectonic index morphometric analysis depicts that it is highly elongated in nature with significant surface tilt and have a greater influence of tectonic deformation in addition the continuous stress from main frontal thrust has a significant role for the landscape upliftment and seismic activity in this region the micro basin which is located in the quaternary alluvial surface has not produced any major earthquake in the past but has greater influence on tectonic activity and may produce earthquake in the future

geomorphic and sedimentary response of rivers to tectonic deformation a brief review and critique of a tool for recognizing subtle epeirogenic deformation in modern and ancient settings abstract rivers are extremely sensitive to subtle changes in their grade caused by tectonic tilting as such recognition of tectonic tilting effects on rivers and their resultant sediments can be a useful tool for identifying the often cryptic warping associated with incipient and smaller scale epeirogenic deformation in both modern and ancient settings tectonic warping may result in either longitudinal parallel to floodplain orientation or lateral normal to floodplain orientation tilting of alluvial river profiles alluvial rivers may respond to deformation of longitudinal profile by 1 deflection around zones of uplift and into zones of subsidence 2 aggradation in backtilted and degradation in foretilted reaches 3 compensation of slope alteration by shifts in channel pattern 4 increase in frequency of overbank flooding for foretilted and decrease for backtilted reaches and 5 increased bedload grain size in foretilted reaches and decreased bedload grain size in backtilted reaches lateral tilting causes down tilt avulsion of streams where tilt rates are high and steady down tilt migration combing where tilt rates are lower each of the above effects may have profound impacts on lithofacies geometry and distribution that may potentially be preserved in the rock record fluvial sedimentary evidence for past tilting is traditionally based on the assumption that depositional features reminiscent of modern fluvial tectonic effects are evidence for past tectonic effects where it is closely associated with historically active structures or where non tectonic causes cannot be invoked however caution must be exercised when using these effects as criteria for past or current tectonic warping as these effects may be caused by non tectonic factors these non tectonic causes must be eliminated before tectonic interpretations are made

soil development over mud rich rocks produces landscape scale erosional instabilities in the northern gabilan mesa california in soil mantled landscapes the length of hillslopes is set by the relative efficiency of hillslope transport processes and incision by channelized flows in cases where rapid channel incision exposes less weathered more resistant rocks incision should slow creating a damping feedback that prevents runaway channel expansion we present observations from the northern gabilan mesa central coast ranges california which is underlain by mud rich rocks that provide less resistance to erosion than the soils produced from them this strength inversion arises because unconfined mud rich units of the pancho rico formation undergo a process called slaking in which pervasive fractures spaced centimeters apart develop when subjected to wet dry cycles in contrast consecutive wetting and drying cycles have produced a cohesive regolith with higher tensile strength than the slaked bedrock exposure of the relatively weak bedrock may create a positive feedback where the acceleration of erosion within the bedrock undermines the cohesive regolith and allows channels to expand headward at the expense of hillslopes geomorphic mapping reveals numerous channelized features that have incised deeply into bedrock and crosscutting relationships and topographic analyses indicate that these features have consumed regions of the landscape previously occupied by hillslopes however these features are only present in south flowing drainages where soil is thinnest and therefore bedrock is most likely to be exposed by increases in erosion rate preferential headward expansion of these south flowing channels has established a profound topographic asymmetry where south flowing tributaries occupy 75 of drainage basin width these results suggest that processes operating at the scale of the critical zone which may be unique to certain rock types conspire to produce an instability that shapes the morphology of drainage basins

tectonics controls on fluvial landscapes and drainage development in the westernmost part of switzerland insights from dem derived geomorphic indices abstract this work focuses particularly on the geomorphological evidence for the tectonic controls on the development of the present day fluvial landscapes in the westernmost part of switzerland the tectonic deformation was evaluated on the basis of a combined analysis of several classical geomorphic indices hypsometric curves and integrals transverse topographic symmetry index and channel s bottom gradients through high precision dem processing a new optimization strategy was applied for defining geomorphic anomalies related to tectonic activity along the channels of three rivers based on a combined investigation of topographic swath longitudinal profiles geological and geophysical observations the results show that the abnormally high values of hypsometric integral are spatially occurred on the hanging walls of thrust faults while abnormally low ones are spatially observed in the same locations of paleo ice stream pathways observations obtained from transverse topographic symmetry index display asymmetries in the most of the studied drainage basins with a predominant se direction of lateral migration this direction is in agreement with the dominant dip direction of the bedding planes within the study area abnormal changes in the channel s bottom gradients which almost coincide in space with pronounced change in the depth of the subsurface geologic layers and in the geophysical properties are marked by distinct topographic relief in areas where rivers flow above blind and emergent faults our analysis not only confirms that there is a significant tectonic control on the evolution of drainage systems but also revealed a possible evidence for the reactivation of some inherited faults

morphotectonics and neotectonic activity of the schuppen belt of mokokchung nagaland india abstract a stretch of the schuppen belt trending ne sw in the western sector of the indo myanmar ranges represents a tectonically active zone deformed quaternary deposits and various geomorphic features lend evidence for the same in a portion of the footwall block of the sanis chongliyimsen thrust the nazira sandstone of the tipam group of mio pliocene age is thrust over tilted quaternary fluvial deposits near tzudikong with a displacement of more than 2 m along the plane of the thrust fault deformed quaternary deposits such as tilted terraces and faulted quaternary sediments are indicative of ongoing tectonic activity in the area the sediments are tilted towards the southeast by varying degrees 21 39 similar to the trend of stream migrations observed at four locations in and around tuli in some sections faulting has not only affected the underlying bedrock but also deformed the overlying fluvial sediments an important morphotectonic feature representing tectonic movement along the kongan thrust is evident from drainage migration in the hanging wall block of the thrust the stream has migrated towards the southeast as a result of nw verging along the kongan thrust which has left behind a trail of palaeochannels numerous palaeochannels mostly linear in nature associated with the scarp of the terrace are indicative of migration of the river stream migrations suggest that the two anticlines noted in the study area are possibly growing in the present tectonic regime multiple levels of strath terraces lend evidence to tectonic pulses in the study area each strath representing a tectonic phase lineaments have been extensively mapped in the area out of which around 70 are parallel to the regional ne sw trend and the other 30 are approximately perpendicular to this trend any movement along the nw se plane may be normal faults the mountain front sinuosity index of the emerging mountain front is close to 1 which is indicative of a relatively active mountain front steam length gradient index and steepness index correspond with each other with high values in the thrust zones which is indicative of a neotectonically active region

multivariate morphological characteristics and classification of first order basins in the siwaliks nepal abstract this study identifies and analyzes a group of interrelated morphometric variables that contribute to the morphology of first order basins in the siwaliks and the adjacent part of the lesser himalaya in the far west nepal first order basins were identified and their various morphometric indices 21 variables such as shape area pattern roughness height gradient angle and distance were obtained from topographic maps scale 1 25 000 and a digital elevation model using a geographic information system the study also identifies the basin types based on morphometric properties and assesses their association with lithology structure and uplift rates a principal component analysis identified seven major components that accounted for 78 of the total variance explained by the original 21 morphometric variables variables loading reveals that the components are the expressions of slope size valley depression basin shape relative massiveness the convergence index and basin asymmetry of these slope and size components explain 48 of the total variance the sets of variables represented by each major component for the entire study area were mostly common to all lithostratigraphic units some variables such as drainage density junction angle and the sediment transport index have associations with more than one group this implies that complex geomorphic processes are involved in the development of basin morphology using the seven major components five basin types were recognized by cluster analysis the distributions of these basin types are similar in the lower and middle siwaliks which have similar geological structures the geometric relationship between the dip and the topography of a homoclinal structure significantly affects the proportion of basin types as evidenced by the contrasting proportions between the cuesta and hogback and among dip anti dip and orthoclinal slopes correlation analysis also confirmed the effect of structure dipping on the morphometric variables and indicated the influence of uplift rates on basin slope stream slope elevation range mean elevation valley angle the shape index and the convergence index associated with the active thrust

assessment of recent tectonic activity on the nw iberian atlantic margin by means of geomorphic indices and field studies of the lower mino river terraces abstract until recently nw iberia was assumed to be tectonically quiescent stable however a combination of tectono morphological analyses demonstrates that neotectonic movements do occur which are in agreement with recent findings by other workers we use a dem based tectono geomorphic approach in combination with field work to assess the presence and nature of neotectonics in the lower mino catchment in nw iberia the area is characterized by clearly developed lineaments coinciding with paleozoic and mesozoic faults and fractures and remnants of a peneplain stepping down towards the coast longitudinal river profiles show knick points where lithological control can be excluded valley shapes show that some valleys have recently been rejuvenated systematic asymmetry tendencies of river catchments indicate tilting of fault bounded blocks finally at several locations faulted terrace deposits of the mino river have been found the types of motions that can clearly be evidenced by our analyses are normal faulting and tilting of fault bounded blocks little clear evidence exists for strike slip faulting whereas reverse faulting has not been found in this study a striking morphological feature of the study area is the presence of small fault bounded basins along the course of the river mino the tectonic movements take place along inherited paleozoic and mesozoic faults which apparently act as weakness zones the reactivation of these faults under the present day stress conditions is probably the reason for the complicated pattern and style of present day tectonic motions that we find the small basins are particularly difficult to explain they could result from the interaction of partially obliquely reactivated strike slip faults step over and normal faults

effects of a low level precursor and frontal stability on cyclogenesis during fastex iop17 the fronts and atlantic storm track experiment fastex has provided comprehensive data to document the life cycle of secondary frontal cyclones over the north atlantic and to improve the understanding of cyclogenesis mechanisms this study analyses the processes leading to the triggering of a particularly well sampled frontal cyclone that developed on the trailing cold front of a mature primary cyclone during fastex intensive observation period 17 iop17 between 16 and 20 february 1997 the case features both a classical low level vorticity strip along the primary front where the frontal cyclone develops and more unexpectedly a pre existing continental surface low further west the importance of which is revealed in the pilot study of arbogast and joly in order to study possible cyclogenetic contributions along the primary front the domain independent vorticity divergence attribution technique of bishop is used to partition the flow into contributions from the continental low and from the large scale environment results indicate that the frontal cyclone is triggered where and when along front stretching decreases below the theoretical critical threshold of bishop and thorpe it is shown that the cyclone is developing under normalized strain less than 1 in agreement with other case studies finally the role of the continental low is investigated using a series of numerical forecasts made from different initial conditions manipulated with a potential vorticity inversion tool the wind attributable to the continental low accounts for roughly 30 of the along front stretching decrease the continental low also has a frontolytic effect on the western part of the primary front where its thermal advection pattern favours cyclogenesis in general terms the frontal cyclone triggering seems to support the bishop and thorpe theoretical framework of frontal instability in low strain areas however a more complex picture arises when considering the role of the continental surface low which also acts as a low level precursor

tectonic geomorphology of the mississippi valley between osceola arkansas and friars point mississippi abstract a geomorphic study of the mississippi river and its alluvial valley between osceola arkansas and friars point mississippi has identified anomalous surface features that can be linked to known geological structures for example relatively recent deformation along big creek fault zone white river fault zone bolivar mansfield tectonic zone blytheville arch crittenden county fault zone and reelfoot rift margins is suggested by river and topographic anomalies faults and plutons appear to affect drainage networks and the morphology of crowleys ridge suggests significant fault control the many anomalies probably reflect a fractured suballuvial surface although movement along these fractures will most likely occur in seismically active areas the probability of movement elsewhere