investigation of the relationships between basin morphology tectonic uplift and denudation from the study of an active fold belt in the siwalik hills central nepal the present study investigates correlations between an extensive range of geomorphic properties that can be estimated from a digital elevation model and the uplift rate on geological timescales the analysis focuses on an area in the siwalik hills central nepal where lithology and climate can be considered as uniform this area undergoes rapid tectonic uplift at rates of up to 15 mm yr 1 which are derived from the geometric pattern of a fault bend model of fold growth the selected geomorphic properties can be divided in two categories depending on whether or not the vertical dimension is taken into account none of the planar properties are significantly correlated to uplift rate unlike those that include the vertical dimension such as the mean elevation of basins hypsometric curve and hypsometric integral and relief defined by the amplitude factor of length scaling analysis correlation between relief and uplift rate is observed for all length scales of topography shorter than 600 m which suggests that all orders of the streams are able to adjust to the tectonic signal simple mass balance considerations imply that the average elevation is only 10 of surface uplift suggesting that a dynamic equilibrium has been reached quite rapidly using a simple two process model for erosion we find that fairly high diffusion coefficients order of 10 m 2 yr 1 and efficient transport of the material by rivers are required this unusually high value for mass diffusivity at small length scales may be obtained by either a very efficient linear diffusion or by landsliding actually both processes may be active which appears likely given the nature of the unconsolidated substratum and the favorable climatic conditions local relief in the study area may therefore be used to predict either uplift or denudation but the prediction is calibrated only for that specific climatic and lithologic conditions and cannot be systematically applied to other contexts

testing the sensitivity of geomorphic indices in areas of low rate active folding eastern betic cordillera spain abstract active deformation structures have an incidence in topography that can be quantified by using geomorphic indices most of these indices have been checked in faulted regions with high deformation rates the application of several geomorphic indices hypsometric curve analysis normalized stream length gradient and valley width to valley height ratio to the drainage network of the southern limb of the sierra de las estancias antiform internal zones eastern betic cordillera where low rate active folding has been recognized allows us to investigate the suitability of these indices to identify active structures in such a scenario hypsometric curves clearly identify regions with recent uplift and young topography but they do not provide any constraint on the location of active folds local valley width to valley height index variations have been detected just coinciding whit the position of ene wsw active folds normalized stream length gradient index serves to locate active folds in areas of hard rock substratum but not in those areas with soft sediments neogene quaternary sedimentary basins this is most likely due to the fact that in the basins erosion is much more intense than in the hard rock sectors in view of these results we consider that geomorphic indices constitute a valuable tool for identifying sectors affected by low rate uplift related to active folding with the best results obtained in hard rock areas

geomorphologic index validation by dinsar technique in the andean orogenic front 32 33 s abstract this paper deals with a morphotectonic characterization of the mendoza piedmont located in the south edge of the andean precordillera 32 33 s very close to mendoza city where at least 800 000 people habits marked tectonic geomorphological expressions exist in this area associated with the andean orogenic active front showing historical earthquakes with magnitudes from 6 0 to 7 0 the main objective of this work is the understanding of current deformation on the study area by two indirect and complementary methods analysis of classic morphometric parameter h index and calculation of deformation fields by dinsar technique applying morphometric analysis of drainage basins of the mendoza piedmont heterogenetic hypsometric values h were found as probable response to different dynamic relations with base level of the fluvial drainage system this segmentation on piedmont behaviour allows us to discriminate three different areas northern central and southern on the basis of morphological criteria the southern area reveals a greater tectonic activity matching with a greater vertical deformation inferred by dinsar technique these findings improve the knowledge about regional seismic hazard allowing release where main deformation is currently being accumulated in the andean active front

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

active tectonics and drainage evolution in the tunisian atlas driven by interaction between crustal shortening and mantle dynamics abstract active tectonics in north africa are fundamentally driven by nw se directed slow convergence between the nubia and eurasia plates leading to a region of thrust and strike slip faulting in this paper we analyse the morphometric characteristics of the northern tunisia sector we aim to identify unknown active tectonic structures and to further understand the mechanisms driving the drainage evolution in this region the interpretation of morphometric data was ground truthed with field data our analysis indicates that recent fluvial captures have been the main factor driving fluvial network reorganization in ne tunisia the medjerda river has increased its drainage area during the quaternary by capturing adjacent axial valleys to the north and south of its drainage divide these captures are probably driven by the gradual uplift of adjacent axial valleys by reverse oblique faults or associated folds like el alia teboursouk and dkhila faults our fieldwork found that these faults cut holocene sediments thus showing recent fault activity the growth and stabilization of the axial medjerda river contrary to the natural transverse drainage development of mature orogens might be caused by a combination of crustal shortening structures and mantle dynamic processes the medjerda river flows sw ne from the south atlassic dextral transfer zone to the regional topographic low defined by the gulf of gabes and the straits of sicily which in turn may be influenced by the underlying tunisian slab in the region

hypsometric control on surface and subsurface runoff 1 a fundamental problem in hydrology is relating the basin hydrological response to the geomorphologic properties of a catchment in this technical note we show that the hypsometric distribution exerts control on surface and subsurface runoff partitioning by isolating its effect with respect to other basin characteristics we conduct simulations using a distributed watershed model for hypsometric realizations developed by modifying the contour line values of a real basin results indicate that the runoff components are a function of the basin hypsometric form in general a relatively less eroded convex basin exhibits higher total runoff that is more dominated by subsurface processes while a relatively more eroded concave basin shows less total runoff with a higher fraction of surface response hypsometric differences are also observed in the relations between base flow discharge and the mean groundwater depth and the variable source area furthermore the hypsometric form reveals clear signatures on the spatial distribution of soil moisture and runoff response mechanisms

geomorphic evidence for northeastward expansion of the eastern qilian shan northeastern tibetan plateau abstract the eastern qilian shan is a tectonically active region consisting of a series of faults with bounded intermountain basins and is located within the transition zone between the mainland tibetan plateau and the alax block active deformation affecting the topography in this region can be quantified based on geomorphic indices therefore we applied the geomorphic indices hypsometry and stream power incision model to evaluate the tectonic deformation pattern of the eastern qilian shan hypsometric curves and s a plots of the selected seven rivers were determined hi values of every single sub basins were also calculated the results show that the local topographic evolution of the eastern qilian shan is in pre steady state and will soon reach its equilibrium state according to the analysis of regional climate condition e g rainfall and glaciers distribution and fault characteristics it is suggested that abundant glacial snowmelt water sustains fluvial incision and tectonic deformation from sustained northeastward expansion of the tibetan plateau is the main reason for the landscape growth combining the research of the deep electric structure beneath the gulang boundary zone we claimed that the eastern qilian shan even the northeastern tibet has been growing and expanding northeastward since the middle miocene and its leading edge now is the hexibao sidaoshan fault on the premise of synthetically considering the western and middle parts of the qilian shan it is suggested that the hexibao sidaoshan fault area will rise into a mountain in 1 2 ma

direct and indirect evaluation of denudation rates in central italy abstract this paper presents the main results of a series of geomorphological studies aimed to the quantitative direct and indirect evaluation of denudation processes in central italy these studies which started in some sample areas since long ago were further deepened and extended to a wider number of drainage basins representative of a variety of morphostructural conditions the complex cause effect relationships among factors influencing both the morphogenesis and the plano altimetric configurations of drainage basins resulted in a large variability in the values of the denudation index tu which ranged from 200 to 2500 t km2 year very high values tu 10 000 t km2 year were obtained for small catchments belonging to the wider basins of ombrone river and tevere river where fast morphological modifications occur due to the action of surface running waters and gravity in the drainage basins affected by the most powerful denudation processes direct measurements of denudation were performed several monitoring stations were equipped with iron stakes and disks to record the local modifications of the topographic surface with time whereas some of these stations have been working continuously since 1993 some others have been running only periodically direct measurements pertinent to periods longer than a decade indicated that mean annual values of denudation range between 1 and 2 5 cm year for slopes affected by sharp edged and or rounded edged badlands higher denudation rates 3 4 cm year were obtained for shorter observation periods still higher rates were recorded for short periods at the gully bottom or in coincidence with mass movements before bench marks were turned up or damaged denudation processes are likely to occur discontinuously they show a step like trend with time and are triggered by rainfall events distributed over a number of consecutive days though not greatly intense particularly their amount should overcome the threshold of 60 mm per 5 consecutive days below this threshold the surface runoff does not seem to reach the power necessary to induce significant modifications of the topographic surface in the study area

systematic variation of bedrock channel gradients in the central oregon coast range implications for rock uplift and shallow landsliding abstract in tectonically active regions bedrock channels play a critical role in dictating the pace of landscape evolution models of fluvial incision into bedrock provide a means of investigating relationships between gradients of bedrock channels and patterns of active deformation variations in lithology orographic precipitation sediment supply and erosional processes serve to complicate tectonic inferences derived from morphologic data yet most tectonically active landscapes are characterized by these complexities in contrast the central oregon coast range ocr which is situated above the cascadia subduction zone has experienced rock uplift for several million years did not experience pleistocene glaciation boasts a relatively uniform lithology and exhibits minor variations in precipitation although numerous process based geomorphic studies suggest that rates of erosion across the ocr are relatively constant it has not been demonstrated that bedrock channel gradients in the region exhibit spatially consistent values analysis of broadly distributed small drainage basins 5 20 km in the central ocr enables us to explore regional variability in bedrock channel gradients resulting from differential rock uplift or other sources consistent with previous studies that have documented local structural control of deformed fluvial terraces in the western portion of our study area our data reveal a roughly 20 km wide band of systematically elevated channel slopes roughly twice the background value roughly coincident with the strike of n s trending mapped folds although many factors could feasibly generate this pattern including variable rock strength precipitation gradients or temporal or spatial variations in forearc deformation the elevated bedrock channel slopes likely reflect differential rock uplift related to activity of local structures importantly our analysis suggests that rock uplift and erosion rates may vary systematically across the ocr although our calculations were focused on the fluvial dominated portion of study basins our results have implications for upstream areas including unchanneled valleys that often serve as source areas for long runout debris flows zero order basins or topographic hollows within the n s trending band of elevated channel slopes tend to be steeper than adjacent areas and may experience more frequent evacuation by shallow landsliding thus this region of the ocr may be highly sensitive to land use practices and high intensity rainstorms

fluvial origin of the valley system in northern victoria land antarctica from quantitative geomorphic analysis a network of sinuous valleys with typical dendritic pattern characterizes northern victoria land nvl in antarctica subparallel to parallel and angular to rectangular patterns are also present quantitative geomorphic analysis of the valley network has been carried out utilizing gis spatial analysis while drainage densities and drainage frequencies show low values segments of the nvl valley network are substantially well organized as indicated by bifurcation ratio r b and direct bifurcation ratio r bd parameters all basins faithfully adhere to horton s laws of drainage network composition quantitative geomorphic analysis suggests that the valley system can be ascribed to fl uvial origin and that consequently a morphoclimatic system completely different from that of present day must have driven its carving the resulting data provide indications about the origin of the valley network and this invaluable information can be used for the reconstruction of earlier phases of glacial history and climatic and tectonic evolution of this signifi cant antarctic region fluvial erosion enhanced the denudation of the transantarctic mountains from at least 55 ma to at least the eocene oligocene boundary ca 34 ma fluvial basins adapted to the tectonic structure following the main regional fault systems a well developed alpine topography postdates the fl uvial morphology temperate glaciers were responsible for denudation until the late miocene parasitic glaciers presently mantle the previously sculpted topography present day glacial erosion is negligible and denudation has been exceedingly slow since 7 5 ma

characterizing structural and lithologic controls on deep seated landsliding implications for topographic relief and landscape evolution in the oregon coast range usa in mountainous areas landslides regulate temporal variations in sediment production and may suppress simple linkages between topographic development and tectonic forcing rates and mechanisms of mass wasting depend on lithology bedrock structure and climatic and tectonic setting these factors tend to vary signifi cantly in active tectonic regions thus clouding our ability to predict how landsliding modulates topographic development over human and geological time scales here we use a novel dem based technique to document the distribution of large landslides in the oregon coast range ocr and quantify how they affect topographic relief we developed an automated algorithm that exploits the distinctive topographic signature specifi cally the relationship between curvature and gradient of large landslides to map their distribution within the gently folded tyee formation eocene deltaicsubmarine ramp sediments in contrast to steep and highly dissected terrain frequently identifi ed as characteristic of the ocr which exhibits steep planar sideslopes and highly curved low gradient ridgetops and valleys terrain prone to large landslides tends to have low values of both drainage density and curvature and gradient values that cluster between 0 16 and 0 44 the distribution of failure dominated terrain in our 10 000 km2 study area is infl uenced by systematic variations in sedimentary facies and bedrock structure the fraction of terrain altered by large landslides 0 1 km2 varies from 5 in the sand rich delta slope and proximal ramp facies southern section of our study area to 25 in the north distal ramp facies coincident with an increase in the thickness of siltstone beds and a decrease in the sandstone siltstone ratio local relief declines progressively northward suggesting that deep seated landsliding is sensitive to the thickness and frequency of low shearstrength siltstone beds and may serve to limit topographic development in the ocr structural controls are superimposed on facies related variations as deep seated landslides are frequently found on slopes whose downslope aspect corresponds to the bedrock dip direction for 1516 strike and dip measurements in our study area we calculated the fraction of proximal terrain 2 5 km altered by deep seated landsliding in the sand rich southern region the proportion of proximal slide dominated terrain increases modestly with bedrock dip in the silt rich northern region terrain altered by deep seated landsliding is pervasive and an increase in dip from 0 to 16 corresponds to a change in the fraction of slide prone terrain from 10 to 28 our technique for mapping large landslides has utility for hazard analysis and land management over million year time scales the progradational character of the tyee formation suggests that continued uplift and exhumation of the ocr should result in a southward propagation of slide prone silt rich distal facies as a result deep seated landsliding will become increasingly prominent and topographic relief in the central and southern ocr will progressively decline whereas spatial variability in climatic or tectonic forcing is often invoked to explain systematic variations in topographic development our results emphasize the importance of structural and intraformation lithologic controls on landsliding as such analyses linking surface processes climate tectonics and landscapes should be couched in the context of diverse geologic and topographic data

testing the applicability of morphometric characterisation in discordant catchments to ancient landscapes a case study from southern africa the ancient landscapes south of the great escarpment in southern africa preserve large scale geomorphological features despite their antiquity this study applies and evaluates morphometric indices such as hypsometry long profile analysis stream gradient index and linear areal catchment characteristics to the gouritz catchment a large discordant catchment in the western cape spatial variation of morphometric indices were assessed across catchment trunk rivers and subcatchment scales the hypsometric curve of the catchment is sinusoidal and a range of curve profiles are evident at subcatchment scale hypsometric integrals do not correlate to catchment properties such as area circularity relief and dissection and stream length gradients do not follow expected patterns with the highest values seen in the mid catchment areas rock type variation is interpreted to be the key control on morphometric indices within the gouritz catchment especially hypsometry and stream length gradient external controls such as tectonics and climate were likely diminished because of the long duration of catchment development in this location while morphometric indices can be a useful procedure in the evaluation of landscape evolution this study shows that care must be taken in the application of morphometric indices to constrain tectonic or climatic variation in ancient landscapes because of inherited tectonic structures and signal shredding more widely we consider that ancient landscapes offer a valuable insight into long term environmental change but refinements to geomorphometric approaches are needed

an assessment of the fluvial geomorphology of subcatchments in parana valles mars this paper uses a multifaceted remote sensing and morphometric approach to investigate if the surface of subcatchments in the parana valles area of mars 20 30 s 0 20 w is reflective of hydrology and sediment transport by water using digital elevation model dem data obtained from the mars orbiter laser altimeter mola three nested subcatchments were examined using a suite of terrestrial geomorphic and hydrologic statistics to determine if their shape and form lies within the known range of fluvial catchment properties on earth further an examination of statistical accuracy via an innovative pixel by pixel solution of two statistics established that despite mineralogical homogeneity confirmed by the compact reconnaissance imaging spectrometer for mars crism spectral survey erosion processes were likely to be variable across the study site the dem based methods outlined here can be employed at other sites to investigate geomorphic properties and attributes of the martian surface

differentiating geology and tectonics using a spatial autocorrelation technique for the hypsometric integral 1 hypsometry is thought to be sensitive to tectonic uplift rates and lithology differences in this study we calculated hypsometric integrals his using as topographic sources two digital elevation models of 10 and 90 m of pixel resolution in the granada basin se of spain the hi spatial distributions do not show clear spatial patterns and do not correlate with basin parameters as mean elevation or relief amplitude however when exploratory spatial data analysis is applied to the data distributions through local indices of spatial autocorrelation clear hot spots are visible that improve the geologic meaning of the hi the distributions are robust and independent of the model resolution but are scale influenced the application of this new method to the granada basin shows a strong correlation between the main distribution of active normal faults in the basin and the clusters of high or low hi values obtained in our analysis clusters with high hi values define the uplifted footwalls of these faults and regions uplifted in relation with rollover anticlines or where epeirogenic uplift has not been counteracted by local extension once the method was adjusted in the granada basin we tested its applicability in an area of known contractive tectonic activity central otago new zealand showing that the meaning of hi values is improved by using the autocorrelation techniques

from extension to transpression quaternary reorganization of an extensional related drainage network by the alhama de murcia strike slip fault eastern betics abstract the complex present day drainage network of the lorca totana area records the changing tectonic setting from extension to transpression in the eastern betics through a detailed morphometric analysis we evaluate the topographic response to this major change in the tectonic setting and the influence in the drainage of miocene extension and middle pleistocene to present day transpression the present day drainage network preserves geomorphic features inherited from late miocene extension that are being overprinted by a new transverse fluvial system this new system advanced towards the nw since the middle pleistocene in response to a localized base level drop related to the ne sw oriented alhama de murcia sinistral reverse fault geomorphic indexes calculated in this work suggest the present day activity of the alhama de murcia fault and the sierra de la tercia anticline the two major tectonic structures in the area the landscape rejuvenation associated with this process results in contrasting mountain front sinuosity values between old and new mountain fronts high slk index anomalies convex shaped and complex hypsometric curves knickpoints in river profiles contrasting slope area plots and high steepness index values this fluvial reorganization was driven progressively by successive fluvial captures preserved as wind gaps in the present day drainage network

hypsometry and relief analysis of the southern termination of the calabrian arc ne sicily southern italy abstract tectonic forcing causes the relief building of mountain chains and enforces the surficial processes in a persistent dismantling of rock volumes continuously modelling earth s surface actually we observe transient landscapes that have temporarily recorded tectonic forcing as a codified signal the late quaternary tectonic evolution of northeastern sicily located along the nubia eurasia plate boundary at the southern termination of the calabrian arc has been dominated by intense plio pleistocene dynamics that severely modified the late miocene landscape the present work aims to investigate geomorphically northeastern sicily essentially focusing on the hypsometric and relief analyses of the region in order to define how the topography responds to the post pliocene tectonic deformation we apply different relief morphometric indices hypsometric integral topographic relief and topographic dissection measured for each differently sized moving window and we use different swath topographic profiles as well our analysis evidences differential morphological responses between distinct morphotectonic domains of the studied area led by the combination of earlier morphological background and late quaternary tectonic deformation stages of the region in addition in the context of a constant and uniform tectonic uplift the results define the general space and time relating pathways of the landscape geomorphic metrics this enables us to bring out the controls of the vertical scale of landscape on hypsometry exploring their mutual relationships finally we reconstruct the late quaternary morphotectonic evolution of the region defining the role played by the main tectonic alignments on the present geomorphic setting

seismic wave attenuation in carbonates 1 the effect of pore fluids on seismic wave attenuation in carbonate rocks is important for interpreting remote sensing observations of carbonate reservoirs undergoing enhanced oil recovery here we measure the elastic moduli and attenuation in the laboratory for five carbonate samples with 20 to 30 porosity and permeability between 0 03 and 58 1 mdarcy contrary to most observations in sandstones bulk compressibility losses dominate over shear wave losses for dry samples and samples fully saturated with either liquid butane or brine this observation holds for four out of five samples at seismic 10 1000 hz and ultrasonic frequencies 0 8 mhz and reservoir pressures attenuation modeled from the modulus data using cole cole relations agrees in that the bulk losses are greater than the shear losses on average attenuation increases by 250 when brine substitutes a light hydrocarbon in these carbonate rocks for some of our samples attenuation is frequency dependent but in the typical exploration frequency range 10 100 hz attenuation is practically constant for the measured samples

fault imaging in sparsely sampled 3d seismic data using common reflection surface processing and attribute analysis a study in the upper rhine graben abstract cost reduction in seismic reconnaissance is an issue in geothermal exploration and can principally be achieved by sparse acquisition to address the adherent decrease in signal noise ratio the common reflection surface method has been proposed we reduced the data density of an existing 3d dataset and evaluated the results of common reflection surface processing using seismic attributes the application of the common reflection surface method leads in all cases to an improvement of the signal noise ratio the most distinct improvement can be seen in the low fold regions the improvement depends strongly on the midpoint aperture and there is a tradeoff between reflector continuity and horizontal resolution if small scale targets are to be imaged a small aperture size is necessary which may be far below the fresnel zone for a specific reflector the substantial reduction of the data density leads in our case to an irrecoverable information loss

geomorphic and tectonic implications of the endorheic to exorheic transition of the ebro river system in northeast iberia the ebro catchment includes a continental foreland basin that underwent an endorheic exorheic transition morphometric studies including hypsometric curves hypsometric integrals asymmetry factor mountain front sinuosity normalised stream length gradient and normalised concavity indices for the ebro river and 32 of its tributaries show the signals of transient response to this major drainage change the ebro river its upper catchment tributaries and the pyrenean tributaries have concave up longitudinal profiles concave hypsometric curves and low hypsometric integrals parameters typical of deeply dissected basins this suggests a mature stage of development controlled by the shift of the base level to the mediterranean sea iberian range tributaries display low concavity profiles with numerous knickpoints and high values of hypsometric integral indicating a transient state as a response to tectonic uplift ratified by the values of mountain front sinuosity surrounding the basin

structural control on drainage network and catchment area geomorphology in the dead sea area an evaluation using remote sensing and geographic information systems in the wadi zerka ma in catchment area jordan the geology of jordan is characterized by fault systems with three major trends 1 nw se the oldest 2 wnw ese and 3 nnw sse the youngest the drainage network of the wadi zerka ma in catchment area located in the middle of the dead sea rift parallels these structural orientations a regional transtensive fault with embedded normal faults bounds the lower and middle part of the catchment area the topographic profile of the zerka ma in river exhibits two major knickpoints where it crosses two major embedded normal faults the second major knickpoint developed as a result of the dramatic lowering of the lisan lake water level a lake that pre dates the dead sea the decreased water level triggered river incision into the clastic sandstone units of wadi zerka ma in we performed a morphotectonic analysis study to investigate how the rock structures control the drainage network and the catchment area geomorphology according to the transverse topographic symmetry factor t the catchment area is highly asymmetric the major basin asymmetry trend is se oriented parallel to the oldest set of fault systems the catchment area displays a convex hypsometric curve indicating a very recent stage in the geomorphologic cycle our study indicates that the lisan lake catchment area shrinkage and structures growth controlled and shaped the wadi zerka ma in catchment area geomorphology the combined use of a geographic information system gis and remote sensing was shown to be very efficient in unraveling the evolution of the drainage network and catchment area geomorphology

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

the effects of lithology and base level on topography in the northern alpine foreland abstract the evolution of topography is driven by climate and tectonics and strongly influenced by substrate properties and different base levels the contributions of these factors may vary in space and time and are thus difficult to disentangle our study area the hausruck kobernauserwald range has a rather uniform climatic and tectonic history but is drained by rivers with different base levels and consists of contrasting sedimentary rocks mainly due to different sedimentation environments this makes them an ideal location to study the effects of lithology and base level on topography to decipher the roles of these influences we used a high resolution digital elevation model and performed a series of morphometric analyses longitudinal river profiles indicate that all channels in the study area independent from base level bed rock and overall morphological expression are well graded hypsometry shows no evidence for base level effects on the present topography while variations in the hypsometric curves coincide with lithological differences this is also reflected in contrasts of mean elevation and slope distributions lithology dependent variations in channel concavity and catchment wide hypsometric integrals show that lithology controls both channel incision and hillslope processes in the study area our results further indicate that variations in channel and catchment metrics are not linked to the prevalence of different rock types alone but to different successions of lithological units along the channels and within the catchments variations in channel slope and geomorphological mapping suggest that lithology dependent landsliding is the dominant process causing the observed large scale landscape diversity in the hausruck kobernauserwald range

tectonic and lithological controls on denudation rates in the central bolivian andes abstract the topographic signature of a mountain belt depends on the interplay of tectonic climatic and erosional processes whose relative importance changes over times while quantifying these processes and their rates at specific times remains a challenge the eastern andes of central bolivia offer a natural laboratory in which such interplay has been debated here we investigate the rio grande catchment which crosses orthogonally the eastern andes orogen from the eastern cordillera into the subandean zone exhibiting a catchment relief of up to 5000 m despite an enhanced tectonic activity in the subandes local relief mean and modal slopes and channel steepness indices are largely similar compared to the eastern cordillera and the intervening interandean zone nevertheless a dataset of 57 new cosmogenic 10 be and 26 al catchment wide denudation rates from the rio grande catchment reveals up to one order of magnitude higher denudation rates in the subandean zone mean 0 8 mm yr compared to the upstream physiographic regions we infer that tectonic activity in the thrusting dominated subandean belt causes higher denudation rates based on cumulative rock uplift investigations and due to the absence of a pronounced climate gradient furthermore the lower rock strength of the subandean sedimentary units correlates with mean slopes similar to the ones of the eastern cordillera and interandean zone highlighting the fact that lithology and rock strength can control high denudation rates at low slopes low denudation rates measured at the outlet of the rio grande catchment abapo are interpreted to be a result of a biased cosmogenic nuclide mixing that is dominated by headwater signals from the eastern cordillera and the interandean zone and limited catchment sediment connectivity in the lower river reaches therefore comparisons of short i e sediment yield and millennial denudation rates require caution when postulating tectonic and or climatic forcing without detailed studies

scale independence of basin hypsometry and steady state topography abstract basin hypsometry has long been used as an indicator of stages in landscape evolution it has also served as a tool for detecting tectonically active regions whether hypsometric curve and its integral are independent of differences in basin size and relief has been discussed in many recent studies the taiwan mountain range the result of an oblique collision between the phillipine sea plate and the eurasian plate provides an excellent opportunity to study landscape evolution in relation to steady state conditions taking advantage of the space for time substitution concerning the building process of taiwanese mountains this study sampled major drainage basins for hypsometric analysis from the southern tip of the island to the northern end this study found that the area previously known as steady state topography is characterized by 1 the hypsometric integral hi close to 0 5 2 s shaped hypsometric curves and 3 normally distributed elevations the response time required for a drainage basin of various strahler orders to evolve from exposure of sub aerial erosion to steady state topography ranges from 0 5 to 2 0 my and is longer for basins of a higher strahler order the hi value of 0 5 for a drainage basin seems critical in terms of landscape evolution the scale dependence of basin hypsometry is manifested mainly by the fact that hi of basins increases as basin order and or basin size decreases this study also found that basin hypsometry is scale independent where topography is in a steady state scale dependence occurs only when drainage basins are in a non steady state the basin hypsometry may therefore be useful to probe into the nature of steady state topography

distribution of hazard types in a drainage basin and its relation to geomorphological setting abstract hazards along a river course in a drainage basin are characterized by three types of events debris flow turbidity flow and flood each has its own channel segment with different sediment transport processes the sediment transport process is controlled by transportation force tractive force and slope direction component of sediment weight both of which are significantly affected by channel slope along large rivers in japan the boundary between the upstream turbidity flow segment and the downstream flood segment is located at the position with a channel slope of about 1 1000 along steep small rivers the boundary between the upstream debris flow segment and the downstream turbidity flow segment is located at the position with a channel slope of about 80 1000 the channel slope depends on the shapes of longitudinal profiles of rivers the longitudinal profiles of japanese rivers main rivers and tributaries can be described by an exponential power or linear function the transportation force of the rivers fitted with exponential functions markedly decreases downstream due to the large curvature of the profiles causing noticeable sediment deposition in the middle courses the transportation force of the rivers fitted with power or linear functions maintains its strength through the whole river courses due to the small curvature causing sediment transportation down to the lower courses the function types are strongly affected by relief in the drainage basins the rivers flowing in small relief areas are fitted with exponential functions and those flowing in large relief areas are fitted with power or linear functions thus the distribution of hazard types along a river course in a drainage basin is controlled by the distribution of relief in the drainage basin

upper crustal structure of the larderello geothermal field as a feature of post collisional extensional tectonics southern tuscany italy abstract reflection seismic profiles crossing the larderello geothermal field permit the distinction of three different seismic facies units in the upper continental crust the upper 3 4 km of the crust is characterized by low reflectivity its base corresponding to a reflector referred to as the k horizon and recognized in many other areas of southern tuscany beneath this reflector a seismic facies of 0 8 1 0 twt thickness is characterized by strong convergent and divergent reflections forming a lozange shaped geometry the lowermost seismic facies is characterized by almost horizontal reflections based on the distribution of the hypocentral microearthquakes temperature data recorded in deep boreholes and the geometry of normal faults the k horizon is explained here as a kinematically active rheological boundary which separates a brittle upper part from a ductile lower part according to this hypothesis the k horizon and the lozange reflections could originate from a mylonite band located at the contact between two geological bodies characterized by different rheological behavior it is inferred that this horizon acts as a decoupling plane in the upper continental crust it developed as a consequence of the extensional tectonics and the high heat flow which characterize southern tuscany

geomorphic evidence of quaternary tectonics within an underlap fault zone of southern apennines italy abstract a composite seismic source the irpinia agri valley fault zone located in the axial sector of the fold and thrust belt of southern apennines italy is investigated this composite source is made up of a series of nearly parallel nw striking normal fault segments which caused many historical earthquakes two of these fault segments known as the san gregorio magno and pergola melandro and the fault related mountain fronts form a wedge shaped right stepping underlap fault zone this work is aimed at documenting tectonic geomorphology and geology of this underlap fault zone the goal is to decipher the evidence of surface topographic interaction between two bounding fault segments and their related mountain fronts in particular computation of geomorphic indices such as mountain front sinuosity s mf water divide sinuosity s wd asymmetry factor af drainage basin elongation b s relief ratio r h hypsometry hi normalized steepness k sn and concavity is integrated with geomorphological analysis the geological mapping and structural analysis in order to assess the recent activity of the fault scarp sets recognized within the underlap zone results are consistent with the nw striking faults as those showing the most recent tectonic activity as also suggested by presence of related slope deposits younger than 38 ka the results of this work therefore show how the integration of a multidisciplinary approach that combines geomorphology morphometry and structural analyses may be key to solving tectonic geomorphology issues in a complex fold and thrust belt configuration

morphotectonics in a low tectonic rate area analysis of the southern portuguese atlantic coastal region south portugal is characterized by low tectonic rates 0 3 mm a with infrequent large seismicity recent studies indicate a coastal region in southwest portugal uplifting at higher rates 0 11 0 01 mm a than the remaining southern portion of portugal 0 04 mm a however the mechanisms that drive this uplift are poorly understood with the purpose of investigating the regional quaternary deformation and its patterns as well as the difference in the uplift rate 77 exorheic drainage basins along 460 km of the southern portuguese coastline were analysed through the application of geomorphic indices in this study we applied stream channel sinuosity s basin relief ratio rh elongation re basin shape ratio bs valley height width ratio vf basin asymmetry factor af hypsometry hi and the stream length gradient index sl and we propose the terminal basin shape index tbs this study aims to 1 identify quaternary deformation along presumed tectonic structures 2 recognize uplift or subsidence along the coastline and 3 test the application of geomorphic indices in low deformation rate environments the cross correlation of results led to the recognition of the sao teotonio aljezur sinceira fault system and the sao marcos quarteira fault as major regional quaternary faults as well as to the interpretation of quaternary activity for other structures spatial differences in uplift rates are identified through basin shape indices and valley height width ratios even for low vertical motion rates whereas other indices were found to be not as sensitive to variations in uplift rate

along strike variations of morphotectonic features in the western foothills of taiwan tectonic implications based on stream gradient and hypsometric analysis abstract the taiwan mountain belt provides a key example for analyzing the relation between morphology and tectonics in an active compressional environment there is a striking geometrical relationship between the location of salients and reentrants of the mountain belt and the presence of major crustal inhomogeneities such as structural highs in the foreland basin major along strike variations of structural styles occur in range front rock units of the fold thrust belt stream gradient and hypsometric analysis has been carried out to highlight the along strike variations of morphotectonic features and to illustrate the relative activities in different tectonic regimes of the western foothills the normalized stream length gradient index sl index and the hack profile are two of the stream gradient indices that effectively reflect the tectonic uplift in a region de trending and residual analysis of the hypsometric integral hi eliminates the spatial dependency of small drainage basins and the residual hypsometric integral corresponds to differential uplift activity integration of stream gradient indices and hypsometry provides more robust tectonic interpretation five morphotectonic provinces have been identified in the western foothills based on stream gradient indices and hypsometry each province is bounded by a series of n140 e trending transfer fault zones either inherited from the eurasian passive margin and or newly formed in the sedimentary cover in response to the presence of basement highs within the foreland basin the peikang and kuanyin highs the morphotectonic features as well as deformation styles vary within each province a high uplift but low shortening rate typifies the crustal deformation style in the transpressional regime north of the peikang basement high on the contrary a low uplift but high shortening rate characterizes the crustal deformation style in the transtensional regime south of the peikang basement high the higher geomorphic indices suggest that greater tectonic activity occurs in central than in southwestern taiwan this inference is also supported by the coseismic deformation of the 1999 chi chi earthquake

changes in the hypsometric curve through mountain building resulting from concurrent tectonics and denudation abstract the stages of geomorphic development of mountains have sometimes been explained based on strahler s diagram of hypsometric curves although the japanese mountains are young they do not follow his diagram hypsometric curves simulated using empirical laws deduced from the japanese mountains indicate that mountain building resulting from concurrent tectonics and denudation does not produce convex curves but concave and or s shaped curves the hypsometric curve of a mountain changes from a concave curve to an s shaped curve in accordance with the increase in mountain altitude the succession of the hypsometric curve during concurrent tectonics and denudation is the reverse of strahler s diagram the hypsometric integral increases with the advance in stage which is evaluated based on the change in mountain altitude it has a relatively good correlation with the stage however the sequence of change in the hypsometric integral is different according to the extent of the terrain examined whether the terrain is restricted to the interior of a mountain or pertains to the whole mountain and whether it includes newly emerged land the stage should be evaluated based on the course of change in the integral characteristics for the extent of the mountain examined

evaluation of the relative tectonic activity in the eastern lake van basin east turkey abstract the eastern part of the lake van basin van region turkey is controlled by reverse faults such as the gurpinar everek and alakoy faults these represent the major tectonic structures within the van region and have caused many devastating earthquakes based on quantitative analyses the quaternary activity and topographic relief control of each of these faults was investigated the gurpinar everek and alakoy faults are restricted to the southern slopes of the guzelsu everek and karasu basins respectively analyses of the mountain front sinuosity smf and valley floor width to height ratio vf suggest high activity along the gurpinar fault the everek fault and the western part of the alakoy fault furthermore based on the integration between smf and vf the estimated uplift rates were observed to increase from north to south the gurpinar and everek hanging wall blocks are characterized by uplift rates of 0 5 mm yr 1 whereas the alakoy fault exhibited a rate of 0 05 to 0 5 mm yr 1 these faults produce knickpoints or knickzones complex basin hypsometric curves and high values of the stream length gradient index based on these geomorphic analyses it was established that the tectonic activity of both the gurpinar and everek faults is greater than that of the alakoy fault

evidence for surface uplift of the atlas mountains and the surrounding peripheral plateaux combining apatite fission track results and geomorphic indicators in the western moroccan meseta coastal variscan paleozoic basement this work represents an initial attempt to link the evolution of the topography in relation to the general tectonic framework of western morocco for this purpose in a section of the western moroccan meseta different tools are combined in order to attain the general objective apatite fission track aft data of granitic rocks of the rabat khenifra area give ages around 200 ma with track length distributions which are compatible with the thermal models already established for the area an inverse correlation between aft ages and elevation is observed which is compatible with previous models indicating northward tilting of the whole western moroccan meseta which is younger than 20 25 ma in order to test this possibility a detailed analysis of the topography at different scales in the estern moroccan meseta has been performed results indicate that two open folds with different amplitudes are recognized and that the one with wider wavelength could correspond to a lithospheric fold as previously stated by other authors on the basis of independent geological arguments the northward tilting proposed based on the aft data agrees with the results obtained in the analysis of the topography which reinforces the presence of a very open fold with a wavelength of 200 300 km in the north western limb of the western moroccan meseta

dynamic interactions between the gulf of guinea passive margin and the congo river drainage basin 1 morphology and mass balance 1 a sediment budget between the congo river drainage basin and the western african margin in the gulf of guinea is proposed on the basis of published and unpublished offshore tertiary isopach maps and onshore digital elevation analysis the overall denudation of that area may be as high as 3 5 106 km3 with a maximum of 10 coming from mesozoic and cenozoic covers the southern part of the congo river basin related to uplift of the south african and kalahari shields appears as the most immature from the morphologic standpoint but provides one third of the present day sediment production it represents a maximum denudation of 150 000 km3 on the easternmost part east african rift drainage basins show a more mature relief and a maximum denudation of 270 000 km3 which can increase to 570 000 km3 if the congo drainage basin had extended up to the east branch of the rift these values are confidently established from the existence of remnant geological surfaces and can explain the volume of tertiary sediment in the gulf of guinea during upper cretaceous the most important accumulations of sediments correspond to the ogooe and kwanza fans which shows that the organization of continental drainage was different as was potential source of sediments in the northern part of the present day congo river drainage basin there was a compressional episode during santonian that may have caused significant relief and erosion along a benue chad axis

morphometric and geomorphic approaches for assessment of tectonic activity dead sea rift israel a series of 31 short parallel steep channels mostly of first or second order occur at intervals of 300 500 m along 16 km of the western margin of the northern dead sea rift israel the analysis of tectonic and geometric activity along the marginal faults between the various segments is based on morphometric parameters such as sinuosity of the mountain front channel gradients drainage basin elongation ratio planimetric ratio facet areas hypsometric curves and integrals longitudinal profiles of the channels were studied in relation to the underlying lithology and the presence of marginal faults despite the great differences in climatic and geomorphologic settings comparison with other studies worldwide showed morphometric values similar to other tectonically active regions the southern segments of the study area which face the hula deep depression indicate enhanced geomorphic and tectonic activity the northern segment proved dissimilar to the others and is explained by its different tectonic setting six sedimentary fan like units composed of polymictic conglomerates were deposited along the mountain piedmont at the channel mouths the units were dated by osl k ar and archaeology to 1 1 ma q 1 and q 1 1 0 56 ma unit q 2 120 ka unit q 3 and 10 ka units q 4 and qs the morphology and structure of the sedimentary units indicate pulses of depositional activity followed by periods of quiescence and calcicsoil development no major faulting occurred along the naftali escarpment during the upper pleistocene despite the high tectonic morphometric values obtained for the study area the marginal faults displaced unit q 2 during the mid pleistocene and since then tectonic activity has shifted from the western marginal faults eastward to younger faults deeply buried in the center of the graben the field data calibrate the morphometric analysis carbonate limestone and dolomite hillslopes developed in the mediterranean climate have maintained active tectonic class morphology since the last major faulting events during the mid pleistocene

scale dependence of hypsometric integrals an analysis of southeast african basins abstract previous studies have shown that the hypsometry of individual drainage basins is sensitive to both tectonic uplift rates and variations in erosional resistance of different lithological units however basin hypsometry has also been found to be related to the size the shape and relief of the sampled area as well as factors such as the type of dominant erosional process this study extends the evaluation of the controls on a basin s hypsometry by assessing factors that might influence the spatial distribution of hypsometric integrals at different scales the method is applied to catchments draining the southeast margin of southern africa kwazulu natal region because of the region s rather uniform runoff a rather well constrained denudational history and a relatively simple coastward sequence of bedrock geology several sets of basins were extracted from an srtm derived 90 m resolution dem one set of main basins those that have outlets at sea level and six sets of sub basins of different size based on strahler order the mean area of the sub basins sampled ranged from 9 km2 for strahler order 2 through to 3215 km2 for strahler order 6 in contrast to previous studies data from this study fail to show a correspondence between hypsometric integral and indices of basin dimension such as basin area and basin relief rather basin hypsometry in se africa varies spatially and with scale in particular a mountain range scale positive hypsometric integral anomaly situated between 10 and 100 km of the coast line was observed but only in basins of strahler order 5 and less this anomaly is compatible with moderate crustal displacement focussed midway between the coast and the drakensburg escarpment some intermediate scale positive hypsometric integral anomalies in basins of strahler order 4 and less was also observed in some cases these anomalies correspond to differences in erosional resistance among major lithological groups finally numerous local basin scale positive hypsometric integral anomalies in basins of strahler order 3 and less were also observed in many cases these latter anomalies are related to local differences in lithological resistance e g the presence of dolerite sills and dikes the analysis of the spatial variation of hypsometric integrals in basins of different size ranges is therefore a useful first step in assessing factors that control landscape development

the structure of the monte amiata volcano geothermal area northern apennines italy neogene quaternary compression versus extension the tectonic evolution of the mt amiata volcano geothermal area is under discussion some authors state that this region as well as the hinterland of the northern apennines were affected by compression from the cretaceous to the quaternary in contrast most authors believe that extension drove the tectonic evolution of the northern apennines from the early miocene to the quaternary field data seismic analyses and borehole logs have been integrated in order to better define the structural features of the continental crust in the mt amiata geothermal area in this paper i propose the hypothesis that the structure of the crust in the mt amiata volcano geothermal area derives from two main geological processes 1 contractional tectonics related to the stacking of the northern apennines cretaceous early miocene 2 subsequent extensional collapse of the hinterland of the mountain chain and related opening of the northern tyrrhenian sea early miocene quaternary compressional and extensional structures characterise the mt amiata region although extensional structures dominate its geological framework in particular the extension produced a middle late miocene boudinage of the previously stacked tectonic units b pliocene quaternary normal faulting which favoured the emplacement of a magmatic body in the middle upper crust and c the eruption of the mt amiata volcano which gave rise to an acid and intermediate volcanic complex 0 3 0 19 ma the extension produced the space necessary to accommodate the middle late miocene marine and continental sediments pliocene and quaternary normal and transtensional faults dissected the previous structures and influenced the early middle pliocene marine sedimentation within the structural depressions neighbouring the mt amiata volcano the magmatic body was emplaced at depth about 6 7 km during the pliocene extension and produced the eruption of the mt amiata volcano during the late pleistocene this gave rise to local uplift presently reaching about 3 000 m as well as a negative bouguer anomaly 16 mgal both centred on the mt amiata area the crustal dome shows a good correspondence with the convex shape of the regional seismic marker known as the k horizon which corresponds to the 450 c isotherm and the areas with greatest heat flow this is probably a consequence of the above cited magmatic body presently in the process of solidification a late pleistocene eruption occurred along a crustal fissure striking n50 mt amiata fault which crosscuts the crustal dome hydrothermal circulation proven by the occurrence of thermal springs and gas vents mainly co2 and h2s mainly occurs along the mt amiata fault both in the northeastern ans southwestern sides of the volcano

effect of drainage area on hypsometry from an analysis of small scale drainage basins in the siwalik hills central nepal hypsometry of drainage basins area elevation analysis has generally been used to infer the stage of geomorphic development and to study the influence of varying forcing factors i e tectonics climate lithology on topography however the scale dependence of hypsometry has generally been neglected in order to assess the scale dependence of hypsometry this study focuses on the sensitivity of hypsometry to different digital elevation model dem resolutions and on the influence of drainage area hypsometry inferred from different dems is shown to be robust against variations of their resolution however hypsometry appears to be dependent on drainage area we propose that this scale dependence may reflect the varying importance of river and hillslope processes with basin area copyright 1999 john wiley sons ltd

active tectonic deformation along rejuvenated faults in tropical borneo inferences obtained from tectono geomorphic evaluation abstract the island of borneo is enveloped by tropical rainforests and hostile terrain characterized by high denudation rates owing to such conditions studies pertaining to neotectonics and consequent geomorphic expressions with regard to surface processes and landscape evolution are inadequately constrained here we demonstrate the first systematic tectono geomorphic evaluation of north borneo through quantitative and qualitative morphotectonic analysis at sub catchment scale for two large drainage basins located in sarawak the rajang and baram basins the extraction of morphometric parameters utilizing digital elevation models arranged within a gis environment focuses on hypsometric curve analysis distribution of hypsometric integrals through spatial autocorrelation statistics relative uplift values the asymmetry factor and the normalized channel steepness index hypsometric analysis suggests a young topography adjusting to changes in tectonic boundary conditions autocorrelation statistics show clusters of high values of hypsometric integrals as prominent hotspots that are associated with less eroded young topography situated in the fold and thrust belts of the interior highlands of borneo high channel steepness and gradients 200 m0 9 are observed in zones corresponding to the hotspots relative uplift values reveal the presence of tectonically uplifted blocks together with relatively subsided or lesser uplifted zones along known faults sub catchments of both basins display asymmetry indicating tectonic tilting stream longitudinal profiles demonstrate the presence of anomalies in the form of knickzones without apparent lithological controls along their channel reaches surfaces represented by cold spots of low hi values and low channel gradients observed in the high elevation headwaters of both basins are linked to isolated erosional planation surfaces that could be remnants of piracy processes the implication of our results is that borneo experiences active folding of the rajang group fold thrust belt to present and these events reactivated old major faults and minor related dislocations from geomorphic analysis associated with sedimentary record we posit that the terrain could have undergone high uplift rates since 5 ma or multi phased uplift with periodic intermittent pulses of high and low uplift rates

seismic depth imaging of a geothermal system in southern tuscany this work represents a case study concerning the application of reflection seismic imaging methods in the context of geothermal exploration our goal is to obtain accurate structural images of a geothermal active area in southern tuscany these images will be required in subsequent studies as the input for geological model building and numerical simulation of the heat transport and fluid flow the target region exhibits great geologic complexity including strong velocity contrasts lateral nearsurface inhomogeneities fracture zones and significant topography those features are typical for a volcanic hard rock environment and pose significant challenges to conventional seismic imaging methodology therefore we apply a sophisticated and robust depth imaging workflow to previously acquired surface seismic data within our workflow we focus on estimating the seismic velocities of the predominant rock units and subsequently carry out kirchhoff pre stack depth migration and fresnel volume migration to obtain high resolution images of the subsurface our results demonstrate that the applied methodology provides a valueable tool for imaging in a complex environment such as a volcano geothermal area in detail the resulting reflector images show the main horizons that delineate the tuscan sedimentary rocks in the target region the images from standard kirchhoff migration can be significantly enhanced by utilizing fresnel volume migration which eliminates migration artefacts and provides a better result moreover we obtain the migration velocities and depths for an important regional reflector known as the k horizon which is of major interest for geothermal characterization

geomorphologic proxies for bedrock rivers a case study from the rwenzori mountains east african rift system geomorphic proxies yield useful insights into understanding long term endogenic and exogenic response to erosion and or rock uplift rates by evaluating areal proxies including asymmetry factor af mountain front sinuosity smf hypsometric integral hi geophysical relief and shape factor shp and linear proxies including normalized steepness index ksn length gradient index slk and chi gradient m the erosion and or rock uplift rates can be quantified we carried out morphotectonic analysis in the rwenzori mountains which represents an anomalously uplifted precambrian horst within the western branch of the east african rift system ears this study aims to 1 evaluate the relationship between geomorphic proxies and drainage basin s maturity 2 evaluate the usefulness of geomorphic proxies as recorders of erosion and or rock uplift rates 3 evaluate the sensitivity of each geomorphic proxy to the drainage basin size and geometry stream order glaciers extent and local structures 4 explore internal correlation within the geomorphic proxies and 5 contribute to the understanding of morphotectonic evolution of the rwenzori mountains for this we computed the stream s good of fitness r2 an indicator of the drainage basin s maturity and geomorphic proxies for the drainage basins and their streams in the rwenzori mountains from the advanced spaceborne thermal emission and reflection radiometer aster digital elevation model dem subsequently we correlated the areal geomorphic proxies with each other and with r2 also we correlated the linear geomorphic proxies with each other and with published erosion rates obtained from cosmogenic 10be analysis our results show that the areal geomorphic proxies af smf hi relief and shp considering the drainage basin size and geometry stream order glacier extent and local structures can be applied to locally evaluate the maturity of the drainage basin we also found that the linear geomorphic proxies ksn slk and m have strong positive correlation with the erosion rates they are effective in detecting fault activities and some of them ksn and m are highly correlated with each other additionally our geomorphic proxy results suggest that the north and south sectors of the rwenzori mountains are in relative tectonic quiescence but that the central sector is experiencing higher levels of erosion and rock uplift

change in the mathematical function type describing the longitudinal profile of a river through an evolutionary process japanese rivers where a large amount of sediment accumulates along the middle reaches are today not at grade nevertheless most of their longitudinal profiles can be described by one of the mathematical functions proposed for graded rivers for these rivers the mathematical function should show an aspect of fluvial processes different from the explanations of grade theories the geomorphological significance of differences in the mathematical functions describing the longitudinal profiles of rivers is discussed here a dynamic change in the shape of longitudinal profile of a river accompanying the change in mathematical function type is proposed in relation to changes in fluvial processes and stage of evolution of a river most japanese rivers can be described by either exponential or power functions the fluvial processes of the rivers described by exponential functions are in the depositional state the front of depositional area of gravels increases in altitude and migrates downstream the rivers exp

estimating drawdown magnitudes of the mediterranean sea in the levant basin during the lago mare stage of the messinian salinity crisis abstract the messinian salinity crisis 5 97 5 33 ma is one of the most dramatic sea level change events in the global geological record during this event marine connection between the atlantic ocean and the mediterranean sea was restricted and episodically blocked while division of the messinian salinity crisis to three major stages is well established and accepted the scale of sea level change at each stage is still debated the magnitudes of the mediterranean fluctuations throughout the messinian salinity crisis have implications for contemporary connectivity between the eastern and western mediterranean basins during the third stage of the messinian salinity crisis commonly known as the lago mare mediterranean sea level fluctuated repeatedly lago mare drawdowns in the eastern mediterranean were estimated earlier to vary between we propose that during the lago mare ravinement along a continuously regressing transgressing coastline abraded the upper continental margin offshore israel the mediterranean regressed to a depth of 380 550 m below present day mean sea level and the eroded strata were evacuated downslope and deposited basinward of this depth as wedge shape clastic complexes during relatively short intervals sea level receded to altitudes 100 m below the erosional surface these sea level recessions exposed a pronounced inflection in the slope gradient to sub aerial processes generating knickpoints and headward migration of incising gullies these gullies developed later into channels conduits for sediment bypass fan deltas were deposited off these channels outlets a major sea level fall towards the end of the messinian salinity crisis reached 630 900 m below present day mean sea level streams incised into the exposed tops of the clastic wedges and fan deltas additionally meteoric water dissolved evaporites within the clastic complexes and formed sinkholes and dolines during this interval the mediterranean sea level fell to below the depth of the sicily sill which separated the eastern and western mediterranean basins this finding reinforces previously proposed paradigms which suggested that the messinian salinity crisis was terminated by spillover events from the atlantic ocean to the western mediterranean basin and consequently from the western to the eastern basin

the topographic imprint of a transient climate episode the western andean flank between 15 5 and 41 5 s mountain range topography is determined by the complex interplay between tectonics and climate however often it is not clear to what extent climate forces topographic evolution and how past climatic episodes are reflected in present day relief the andes are a tectonically active mountain belt encompassing various climatic zones with pronounced differences in rainfall erosion and glacier extent under similar plate boundary conditions in the central to south western andes climatic zones range from hyperarid desert with mean annual rainfall of 5 mm a 22 5 s to year round humidity with 2500 mm a 40 s the andes thus provide a unique setting for investigating the relationship between tectonics climate and topography we present an analysis of 120 catchments along the western andean watersheds between 15 5 and 41 5 s which is based on srtmv3 90m data and new medium resolution rainfall tropical rainfall measurement mission trmm dataset for each basin we extracted geometry relief and climate parameters to test whether andean topography shows a climatic imprint and to analyze how climate influences relief our data document that elevation and relief decrease with increasing rainfall and descending snowline elevation furthermore we show that local relief reaches high values of 750 m in a zone between 28 s to 35 s during pleistocene glacial stages this region was affected by the northward shifting southern hemisphere westerlies which provided moisture for valley glacier formation and extended glacial coverage as well as glacial erosion in contrast the southern regions between 35 s to 40 s receive higher rainfall and have a lower local relief of 200 m probably related to an increased drainage density we distinguish two different climatically controlled mechanisms shaping topography 1 fluvial erosion by prolonged channel hillslope coupling which smoothes relief and 2 erosion by valley glaciers that generates relief finally our results suggests that the catchment scale relief of the andes between 28 s to 35 s is characterized by a pronounced transient component reflecting past climatic conditions copyright 2010 john wiley sons ltd

a geomorphological approach to determining the neogene to recent tectonic deformation in the coastal cordillera of northern chile atacama the large 10000 km2 and local scale 300 m sedimentary succession was deposited east of the afs the succession fills previously deep paleovalleys and it consists of gravel so called atacama gravels which passes laterally into fine grained playa related deposits near the afs we interpret the deposition of this succession as a result of a blocking closure of the valley flowing from the precordillera due to the activity on afs a pedimentation episode followed sediment deposition and is locally strongly re incised by the main modern day river valleys draining the precordillera incision may result from either regional uplift of the forearc and or from more localized activity on the afs furthermore recent quaternary tectonic activity on the afs has been observed which is consistent with a localized relative uplift of the crustal block west of the afs

comparative study on dynamic shear behavior and failure mechanism of two types of granite joint abstract frictional instability such as fault slip rockburst injection induced earthquake and landslide is frequently associated with the unstable sliding of pre existing discontinuities this study aims to investigate the influence factors and mechanism of the unstable sliding of granite joints two types of granite granite a and granite b which are mainly composed of microcline albite quartz and biotite are used to prepare a number of splitting joints with the average jrc values of 12 7 and 15 7 respectively direct shear tests are then conducted under various normal stresses during which acoustic emissions are monitored and recorded test results reveal that the peak shear strength is generally greater for joint b than joint a while the post peak failure intensity with respect to post peak stress drop amplitude of stick slip peak energy rate the sound emitted during stress drops for joint b are smaller than that of joint a especially under the high normal stress condition the underlying contributing factors are studied according to the petrographic observation and the two dimensional joint surface roughness analysis the higher peak shear strength for joint b is related to the rougher joint surface which is associated with a larger mineral grain size the more violent post peak failure intensity in joint a is related to its smaller mineral grain size compact structure and fewer inherent cracks which favor a greater energy build up in the asperities the present study suggests that not only the roughness of discontinuity plane but also the micro texture of the host rock should be considered in the assessment of the fault slip rockburst hazards caused by the unstable sliding results of this research contribute to the better understanding of mechanism and influencing factors of fault slip rockburst as well as the mitigation of geohazards induced by the dynamic shear failure of rock discontinuities

tectonic climatic and lithologic influences on landscape fractal dimension and hypsometry implications for landscape evolution in the san gabriel mountains california east west variation in tectonic activity and strong north south climatic gradients provide a unique opportunity to study tectonic climatic and lithologic influences on landscape evolution in the san gabriel mountains california the competing tendencies of constructive tectonic and degradational climatic effects act against lithologic resistance to influence fluvial systems and thus the nature of adjacent and nested drainage basins landscape fractal dimension d a measure of surface roughness over a variety of scales and the hypsometric integral i a measure of the distribution of landmass volume above a reference plane are useful measures of altitudinal variation with scale as such they may provide clues as to the relative influences of tectonism climate and rock type topographic analyses of the san gabriel mountains clearly indicate that tectonism strongly influences d at range wavelength scales while rock type variation apparently influences d and i at smaller scales tectonism is also shown to influence i across the mountain piedmont junction at all scales investigated tectonic activity shows strong negative correlation with both i and d because tectonically active portions of the mountain front do not allow time for much landscape dissection by lower order streams three dimensional topographic modeling suggests climatic parameters exert a stronger influence on d than does tectonism this modeling also suggests an inverse correlation between range scale d and i with varying climate and uplift rate a positive correlation is observed in the san gabriel mountains we suggest this difference results from 1 differences in uplift style between the san gabriel mountains and the models and or 2 variation in rock type erodibility present in the san gabriel mountains but which was not modeled we postulate that the interaction of tectonic climatic and lithologic parameters influences the stable i and d to which a landscape evolves key questions remaining include 1 the time required to reach a stable i or d after a climatic or tectonic change 2 what does the fractal nature of topography tell us about the scaling characteristics of major landforming processes 3 how does climate influence range scale i and both range and small scale d and 4 what are the effects on i and d of range scale lithologic variation both in the models and in real landscapes

landscape evolution of the eastern himalayan syntaxis based on basin hypsometry and modern crustal deformation abstract basin hypsometry is sensitive to tectonic uplift and erosion an area of intense tectonism the eastern himalayan syntaxis ehs is used to explore the characteristics of basin hypsometry and discuss the dominant variables controlling landscape evolution we selected 137 primary drainage basins and delimited their subordinate basins according to strahler order the hypsometric integrals and corresponding hypsometric curves of catchments are spatially independent of lithologic factors and basin scales but correlate strongly with indices of vertical dimension of drainage basins i e mean altitude and maximum altitude these observations also suggest different relationships between tectonic uplift and surface erosion around the namche barwa syntaxis nbs the area northwest of the nbs the nbs itself and the chayu deformation belt are in stages of sinking approximate steady state and rising respectively combined with gps data and the regional earthquake distribution we suggest that the present tectonic uplift of the ehs is concentrated in the nbs and the chayu deformation belt to the southeast of the nbs while the actual uplift of the earth s surface and significant horizontal crustal shortening is only concentrated within the chayu deformation belt the center of crustal deformation of the ehs therefore is inferred to have migrated southeastward from the nbs to the chayu deformation belt

landscape maturity fold growth sequence and structural style in the kirkuk embayment of the zagros northern iraq abstract the kirkuk embayment is located in the southwest of the zagros fold and thrust belt of iraq like fold and thrust belts worldwide the zagros is conventionally understood to have grown sequentially towards the foreland here we use landscape maturity analysis to understand anticline growth in the embayment digital elevation model dem based geomorphic indices hypsometric integral hi surface roughness sr and their combination surface index si have been applied to quantify landscape maturity the results inform new ideas for the sequence of anticline growth maturity indices are highest for the qarachauq anticline in the center of the embayment then makhool himreen to the south and lastly the kirkuk anticline to the north the pattern suggests the growth sequence is not classical piggy back thrusting this result fits the exhumation record which is loosely constrained by the stratigraphic exposure level favored hypotheses for fold growth order are either i the folds have grown at different times and out of sequence qarachauq first then makhool himreen and kirkuk last or ii the growth occurred with different rates of exhumation but at broadly the same time there are few constraints from available data on syn tectonic sedimentation patterns fold growth across much of the embayment might have begun within a limited timeframe in the late miocene pliocene during the deposition of the mukdadiyah formation another hypothesis is that folds grew in sequence towards the foreland with different rates of exhumation but we consider this less likely we also construct a new cross section for the embayment which indicates limited cenozoic strain 5 shortening analysis of topography and drainage patterns shows two previously undescribed anticlines with hydrocarbon trap potential between the makhool and qarachauq anticlines

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

the river it goes right on post glacial landscape evolution in the upper waipaoa river basin eastern north island new zealand abstract post glacial incision created 50 to 120 m of relief in the headwaters of the waipaoa river basin but it is not known how the signal of incision propagated along the trunk streams we addressed this issue by imposing previously determined long term rates of rock uplift that vary between 0 6 and 4 mm year 1 on the preaggradation longitudinal profile acting over the past 27 1 2 cal ka bp these rates are sufficient to passively elevate the waipaoa 1 terrace to its present level but during the last glacial maximum rates of vertical incision failed to match those of the uplifting rocks thus by the time favorable conditions for incision were reestablished after the antarctic cold new zealand late glacial reversal we estimate that the channel would have been elevated 55 m above the datum the river should otherwise have maintained the channel incised rapidly after the transition from glacial to interglacial conditions and reacquired its steady state form in the mid holocene 5 5 2 cal ka bp thereafter we suggest rates of incision matched rates of uplift no knickpoints are found on the upper waipaoa and mangatu rivers because incision commenced simultaneously along the entire length of the trunk streams and the pattern of incision is consistent with the downstream decline in the rate of rock uplift we also used hypsometric analysis to show how post glacial incision affected the surface morphology of low order 0 1 4 3 km 2 drainages in the headwaters of the waipaoa river basin values of the hypsometric integral are higher for proximal basins which the incision signal did not permeate than for low order basins bordering the upper waipaoa river and the lower reaches of tributaries that possessed enough erosive capacity to keep pace with incision along the mainstem hillslope adjustments were focused on the lower and mid sections of these basins so that the most pronounced changes to the hypsometric curve occur in the vicinity of the toe whereas the entire form of the hypsometric curve changes once mass wasting processes encroach onto hillslopes in the middle and upper sections of a basin

quantifying landscape differences across the tibetan plateau implications for topographic relief evolution 1 we quantify the bulk topographic characteristics of the tibet qinghai plateau with specific focus on three representative regions northern central and southeastern tibet quantitative landscape information is extracted from shuttle radar topography mission digital elevation models we find that the morphology of the tibetan plateau is nonuniform with systematic regional differences the northern and central parts of the plateau are characterized by what we suggest to call positive topography i e a topography in which elevation is positively correlated with relief and mean slope a major change from the internally drained central part of tibet to the externally drained part of eastern tibet is accompanied by a transition from low to high relief and from positive to negative topography i e a topography where there is an inverse or negative correlation between elevation and relief and between elevation and mean slope relief in eastern tibet is largest along rivers as they cross an ancient eroded plateau margin at high angle to the major strike slip faults the yalong yulong thrust belt implying strong structural control of regional topography we propose that the evolution of river systems and drainage efficiency the ability of rivers to transport sediments out of the orogen coupled with tectonic uplift is the simplest mechanism to explain systematic regional differences in tibetan landscapes basin filling due to inefficient drainage played a major role in smoothing out the tectonically generated structural relief this mode of smoothing started concurrently with tectonic construction of the relief as most clearly illustrated today in the qilian shan qaidam region of the northeastern plateau in the interior of tibet further passive filling due to internal drainage only continued to smooth the local relief millions of years after the cessation of major phases of surface uplift due to crustal shortening thus diachronous beveling at high elevation produced the low relief surface of the high plateau in southeast tibet headward retreat of external drainages brought back in the global ocean base level first disrupting then interrupting the relief reduction process it produced a transitional topography by dissecting the old remnant plateau surface which introduced younger and steeper incision of this hitherto preserved high base level this provides a unifying mechanism for the formation of the low relief plateau interior and for the origin of the high elevation low relief relict surface in southeastern tibet our analysis brings forth the importance of surface processes in particular drainage efficiency in shaping plateau morphology and landscape relief such key processes appear to have been mostly ignored in numerical models of plateau deformation our results also cast doubt on and provide a more realistic alternative to the fashionable contention that a continuous preuplift low relief surface first formed at low elevation extending all the way to the south china sea shore before being warped upward in the late miocene pliocene by lower crustal channel flow

morphotectonics of the northern bogd fault and implications for middle pleistocene to modern uplift rates in southern mongolia abstract assessing the activity of strike slip faults is often facilitated by cumulative offsets of morphological features the december 4th 1957 mongolia earthquake generally referred to as the gobi altai or bogd earthquake had mw 8 1 and created long and complex surface ruptures of c 350 km length along the bogd fault that cuts across the foothills of the gurvan bogd mountains several left laterally and vertically displaced quaternary alluvial fans and morphogenic markers show cumulative offsets allowing for an assessment of the effect of repeated earthquakes and active tectonics on landscape evolution we propose to expand the active tectonic record along this fault up to a middle pleistocene time scale that spans regional climatic fluctuations i e repeated glacial interglacial cycles and hence varying erosional and depositional rates five main drainage areas crosscutting the north ikh bogd segment of the bogd fault were analysed and compared in terms of hypsometry drainage steepness and alluvial fan slope inclination along the mountain front deposits from all drainages form multiple alluvial fan levels that reflect recurring deposition incision cycles previously published ages as well as the spatial distribution of these fan levels suggest that their incision and abandonment is induced by regionally dominant climate fluctuations however the increase of fan slope angles over time and the increased intensity of sub surface folding observed in ground penetrating radar profiles suggests that cumulative tectonic uplift also has a strong impact on alluvial fan morphology estimates of the increase of fan slope angles as a result of cumulative tectonic uplift imply that middle pleistocene to modern vertical slip rates along the north ikh bogd segment of the bogd fault are in the order of 0 9 1 mm yr however much slower vertical slip rates along individual fault segments ranging between 0 06 0 01 mm yr and 0 28 0 07 mm yr indicate that uplift of the ikh bogd plateau occurs as a result of distributed deformation across multiple parallel fault strands within bedrock as well as alluvial fans our results emphasise the importance of regional studies along active faults that take into account the complexity of surface ruptures as well as the occurrence of related structures that can accommodate deformation