assessment of multiple and interacting modes of soil loss in the karst critical zone southwest china swc abstract in southwest china swc soil loss is becoming a serious threat to the sustainable development of resources and the health of the environment a large number of studies have been conducted to investigate the causes e g environmental factors and human activities and impacts e g karst rocky desertification of soil loss however the following are some important problems related to soil loss in the karst of swc 1 although soil loss is caused by chemical weathering gravity and water interaction in karst the mechanisms by which soil loss takes place in the swc and their interaction are still not clear 2 subsurface soil loss varies under different geological and hydrological conditions and there is still no consensus on the common the ratio between surface soil erosion and underground soil loss 3 traditional methods for soil loss risk assessment are difficult to apply over the whole of swc and 4 a large number of studies have been published only in chinese and remain inaccessible to the international science community therefore a review paper is needed to address this gap and introduce the contributions of chinese researchers to soil loss in karst this paper proposes a novel modelling approach for the grouped soil loss styles and presents a comprehensive discussion for the mechanism causes and risk assessment of the various soil loss styles in swc karst

the soil leakage ratio in the mudu watershed china soil leakage in karst areas is an important geomorphic agent of environmental interest there are several viewpoints concerning soil leakage ratios one viewpoint states that the soil leakage ratio is high in karst regions whereas others consider that it is very low this paper s objective is to describe the soil leakage phenomena qualitatively and quantitatively in the chongqing karst china by conventional methods such as monitoring runoff plots and paint traces drawn on piles and walls found within runoff plots and by measuring the activity of the isotope 137cs at small medium and large spatial scales this paper s results show that soil filled karst cracks occurred at a small spatial scale with soil leakage ratios ranging from about 3 to about 34 at two abandoned quarries and six soil profiles with rock karst crack development the soil leakage ratio was almost zero at the medium spatial scale the soil leakage ratio was 4 50 and the surface soil erosion ratio was 95 50 of the total soil erosion at the large spatial scale it is concluded that soil leakage ratios in the study area were low at a large spatial scale and that cracks in karst were filled with soil at small spatial scales this paper s results indicate that soil leakage phenomena vary depending on the processes acting at the small medium and large spatial scales

hydrological response and soil detachment rate from dip anti dip slopes as a function of rock strata dip in karst valley revealed by rainfall simulations rock dip angle plays a significant role in surface hydraulic characteristics and leads to different spatial distribution of water and soil loss in karst trough valleys in this study the rock dip angle effect on the hydraulic characteristics and soil detachment rate on dip anti dip slopes was explored via rainfall simulations and a steel experimental flume the rainfall intensities ranged from 30 to 90 mm h and the rock dip angles varied from 10 to 60 the results revealed that i surface runoff on the dip slope was higher than that on the anti dip slope whereas underground runoff presented opposite results the 30 rock dip angle presented the critical flow velocity for the anti dip slope and the flow velocity reduced as the rock dip angle of the dip slope increased ii laminar water flow occurred on the dip anti dip slope re was 500 in all cases for the anti dip slope the re value reduced by 3 53 89 79 the fr value reduced by 34 13 73 04 and the f value increased by 61 07 93 78 compared with that of the dip slope iii a linear function model can describe the relationship between the soil detachment rate and hydrodynamic parameters w and e it was found that w was the best of the hydrodynamic parameters to describe the soil detachment rate these results could provide valuable information for establishing a national scale empirical soil erosion model for karst trough valley

sequence stratigraphy in active extensional basins implications for the interpretation of ancient basin fills abstract systematic variations in sequences their component units and their stacking patterns exist within rift basins these variations can be related to displacement gradients associated with the large scale 12 50 km segmentation of normal fault zones which control accommodation sediment supply and basin physiography sediment supply is also strongly influenced by the nature of pre rift drainage networks and variations in bedrock lithology high rates of hangingwall subsidence close to the centre of normal fault segments may cancel out the effects of glacio eustatic sea level fall so that accommodation development is normally characterized by the continual addition of new space the resulting sequences lack type 1 sequence boundaries and lowstand systems tracts and stack into aggradational sequence sets the adjacent footwall is subject to uplift which may lead to subaerial exposure and incision generating a composite type 1 sequence boundary away from the fault zone and near segment boundaries slip rates are much lower and hence relative sea level change is dominated by eustasy here falls in relative sea level are important resulting in type 1 sequences sequence stacking patterns reflect not only eustasy and local fault controlled subsidence but also the interaction of these with adjacent uplifting footwalls and or regional uplift tectonic influence on sequence development will be more pronounced during greenhouse times than icehouse times

erosion creep collapse mechanism of underground soil loss for the karst rocky desertification in chenqi village puding county guizhou china carbonate rocks distribute widely in china the total area of the carbonate rocks is about 3 430 000 km 2 and the exposed area of the carbonate is approximately 13 of china s territory in 2003 soil loss in yunnan guizhou and guangxi provinces reached 179 600 km 2 which is almost 40 1 of the total area causing rocky desertification in this study the erosion creep collapse mechanism of underground soil loss for the karst rocky desertification in chenqi village puding county guizhou province is proposed the mechanism occurs under the following geological environment slope surface undulation underlying bedrock surface fluctuation and thin and inhomogeneous soil overlying overlying soil generation by bedrock weathering underground karst development and large groundwater depth and lying water table under the bottom of soils the erosion creep collapse mechanism of underground soil loss in the karst slopes is explained as follows power loss due to human cultivation activities that destroy the soil structure hydraulic force formed by rainfall infiltration wet dry cycle generated by rainfall erosion effect caused by rainfall penetration creeping and flowing of plastic stream soil and collapse the erosion creep collapse mechanism of underground soil loss has seven steps disturbance of soils filled in underground karst cave by human activities internal soil erosion and partial collapse caused by hydraulic power internal free surface formation within the soil in the filled karst cave internal soil creeping soil pipe formation soil pipe collapse and ground surface collapse and filling soil loss develops slowly and sudden transportation occurs by collapse soil loss can be explained by the proposed mechanism and soil loss can be prevented by controlling soil collapse

characteristics of red clay creep in karst caves and loss leakage of soil in the karst rocky desertification area of puding county guizhou china the loss of surface soil and water in the karst rocky desertification area of carbonate rock in chenqi village puding county guizhou province was monitored in this study the results show that the major form of surface soil loss in the area is the loss of soil through underground channels a creep test of red clay formed by loss through underground channels was conducted the results of the test show that the creep curve of the red clay samples includes two stages attenuation creep stage and stable creep stage the creep law for the red clay samples in the karst cave can be described by buger s model the parameters of buger s equation were deduced by fitting the creep curve which provides the reference for analyzing the surface soil loss leaking through the underground channels

significance of preferential flow at the rock soil interface in a semi arid karst environment abstract in many semi arid environments the surface materials are frequently characterized by thin soils and large proportions of bare rock both of which are expected to considerably influence infiltration and groundwater recharge processes in this study small plot scale irrigation experiments in combination with dye tracer application as well as real time and subsequent soil moisture measurements and soil particle size analysis were conducted to investigate the significance of preferential flow at the rock soil interface large scale assessments of soil depth and surface type distribution were used to upscale the findings of the irrigation experiments to the scale of a complete hillslope and further to estimate percolation properties of a hypothetical rainfall event the two experimental plots were each located in the west bank mountains close to ramallah each irrigation experiment was designed with 50 mm of precipitation applied on an area of 1 m 2 during the course of ca 2 5 h each irrigation plot had a surface share of approximately 50 rock outcrop and 50 soil surface percolation properties were investigated by subsequent soil moisture measurements at high spatial resolution on vertical soil profiles on the irrigated plot dye tracer application on the rock outcrop during the sprinkling allowed for tracking of resulting outcrop runoff in the subsurface the soil depth survey included 2100 measurement points on 7 transects which allowed the estimation of local soil depth distribution results of the irrigation experiments showed that precipitation induced runoff from rock outcrops continued below ground as preferential flow along the rock soil interface while water from the soil surface percolated mainly vertically and much more homogeneously this was evident from the high density soil moisture measurements as well as from the dye tracer patterns outcrop runoff percolated faster and to greater depths than water infiltrating directly from the soil surface thus possessing a greater potential for groundwater recharge

effects of rock fragments on soil erosion by water at different spatial scales a review this paper reviews the various effects of rock fragments on soil erosion by water since these effects are scale dependent they are investigated at three different nested spatial scales the microplot 4 10 6 100m2 the mesoplot 10 2 102 m2 and the macroplot 101 104 m2 for each scale the corresponding process mechanisms are discussed particular attention is paid to the effects of rock fragment cover on the intensity of soil erosion processes at the mesoplot scale i e on interrill areas rock fragments at the soil surface can have negative as well as positive effects on sediment yield these ambivalent effects are conditioned by the type of fine earth porosity soil surface slope vertical position and size of rock fragments and by the occurrence of horseshoe vortex erosion at the microplot scale i e the soil surface area which is covered by a single rock fragment and at the macroplot scale i e upland areas where both interrill and rill erosion takes place rock fragments at the soil surface have a negative effect on sediment yield in these two scales rock fragments can thus be considered as natural soil surface stabilizers at the macroplot scale the mean decrease of relative interrill and rill sediment yield with rock fragment cover can be expressed by an exponential decay function the scatter of the data indicates that a given rock fragment cover can have different efficiencies in reducing interrill and rill sediment yield depending on the varying intensities of the hydrological and erosion subprocesses these findings have implications for erosion modelling and soil conservation

role of underground fissure flow in near surface rainfall runoff process on a rock mantled slope in the karst rocky desertification area abstract because of the complex near surface double layer geologic structure i e surface and underground fissures of slopes in karst regions it is difficult to collect data on all flows especially the flows generated in underground fissures this lack of information leads to a poor understanding of the rainfall runoff process associated with soil loss in karst landscapes the goal of this study was to determine the output characteristics of surface subsurface and underground fissure flows and their conversion relationships as well as the role of underground fissure flow in the near surface rainfall runoff process using rainfall experiments the results revealed the following findings light rainfall intensities 15 and 30 mm h generated subsurface lateral flow and underground fissure flow whereas greater rainfall intensities generated surface runoff in addition to subsurface and underground flows ii the runoff drainage depths of all the above flows increased with increasing rainfall intensity while the runoff drainage coefficient exhibited no obvious regular change except for the surface runoff moreover the distribution ratio of surface runoff to total flow also increased with increasing rainfall intensity but decreased with increasing underground fissure degree while the distribution ratio of underground fissure flow exhibited the opposite trend iii underground fissure flow with distribution ratios of 27 8 78 0 dominated the total flow yield this study has significance for controlling soil erosion and water shortage in the karst rocky desertification region and also improves the understanding of the near surface rainfall runoff process in this region

tectono sedimentary development of an extensional basin the neogene megara basin greece the miocene pliocene to pleistocene succession exposed in the megara basin comprises a grossly coarsening upwards sequence at least 1 km thick the oldest strata exposed in the nw record the establishment of alluvial fans and axial streams these drained into a lacustrine environment subject to minor wave and possibly tidal action the lower part of the central basin fill is comprised of marls siltstones sandstones and conglomerates they record the pulsed infill of the predominantly freshwater lake megara by progradation of a network of shallow multichannel streams which drained a western hinterland containing ultrabasic rocks cherts and limestones frequent examples of large scale soft sediment deformation structures and stratigraphic thickening into hangingwall rolloven indicate active fault control of sedimentation the lake river interface featured gilbert deltas which were subject to periodic transgression by climatically controlled lake expansions the upper part of the pliocene basin fill largely comprises fluviatile gravels but with two important marine transgressional horizons and renewed calcareous mar1 deposition including a basinwide tufa horizon towards the top the overlying pleistocene alluvial clastics were deposited by a nw flowing system and thicken markedly into a major basin bounding fault deposition of these fluvial deposits was interrupted towards the top of the sequence by the rapid deposition of monomict limestone breccias of debris flow origins which are believed to mark a catastrophic event at some time in the late pleistocene c 1 ma the basin bounding faults became inactive and the entire basin fill was inverted in response to uplift in the footwall of the active major fault strand that bounds the se margin of the alkyonides gulf

dating reservoir deposits to reconstruct sediment yields from a small limestone catchment in the yimeng mountain region china abstract in this study we use reservoir deposits to reconstruct sediment yields over the past 50 years from the quananzi catchment a small limestone catchment in the yimeng mountain region china three sediment cores were collected from the reservoir and the chronology of each core was established using 137cs and 210pbex dating the area specific sediment yields ssy for different time periods since dam construction were estimated from each core by referring to the original capacity curves of the reservoir the estimated ssy from the quananzi catchment in each core for each period ranged between 0 9 0 3 and 2 6 0 9 t ha 1 y 1 with a mean value of 1 8 0 6 t ha 1 y 1 which is low compared with reported ssy from catchments worldwide the mean value was only about 1 7 of the equivalent value reported from the jiangzhang catchment in the granite area of the yimeng mountain region this low ssy reflects the shortage of erodible luvisols resistance to erosion and the limited effect of human disturbance in this small limestone catchment the decrease in ssy from 1959 to1972 suggests that the effect of the deforestation that occurred in 1958 on soil erosion decreased with time the continual increase of ssy through the two subsequent periods after 1972 reflects the expansion and intensification of cultivation during this time however the decreased ssy over the latest period of 1998 2012 can be related to the limitations imposed by the karst landscape on cultivation and to the impact of increasing numbers of residents leaving the area since the end of the 1990s to become temporary migrant workers elsewhere resulting in a decrease in human activity in the area overall the trend in ssy reflects the general history of changing human disturbance in this small limestone catchment over the past 50 years the results indicate that reservoir deposits provide a means of estimating the historical sediment yields from a karstic environment

occurrence mechanism and prediction of rocky land degradation in karst mountainous basins with the aid of gis technology a study case in houzhai river basin in southwestern china rocky desertification is a severe ecological issue threatening and constraining regional sustainable development in karst mountainous areas like houzhai river basin in southwestern china the results indicate that slope gradient and altitude are closely associated with occurrence of rocky desertification in the study region and there are some significant correlations between rock outcrop and slope gradient r 0 363 p 0 001 and between rock outcrop and altitude r 0 0 336 p 0 001 slope gradient and altitude are key factors contributing to rocky desertification in the studied basin therefore special attention should be paid to sloping lands that have greater slope gradients or altitudes to prevent and control the rocky desertification in a karst mountainous basin as the houzhai river basin furthermore it might be possible to predict the occurrence of rocky desertification using neural networks on the basis of geographical characteristics and human disturbance the correlation coefficients between observed values and predicted values ranged from 0 728 to 0 905 with a mean value of 0 851 ten times repeats the present study also indicates that human disturbance has little effect on rocky desertification however further studies should be conducted to interpret the effects of agricultural activities on the occurrence of rocky desertification

soil erosion rates in two karst peak cluster depression basins of northwest guangxi china comparison of the rusle model with 137cs measurements reliable estimation of erosion in karst areas is difficult because of the heterogeneous nature of infiltration and subsurface drainage understanding the processes involved is a key requirement for managing against karst rock desertification this study used the revised universal soil loss equation rusle to estimate the annual soil erosion rates on hillslopes and compared them with cs 137 budget in the depressions at two typical karst peak cluster depression basins in northwest guangxi southwestern china runoff plots data were used to calibrate the slope length factor l of the rusle model by adjusting the accumulated area threshold the rusle model was sensitive to the value of the threshold and required dems with 1 m resolution due to the discontinuous nature of the overland flow the average annual soil erosion rates on hillslopes simulated by the rusle were 0 22 and 0 10 mg ha 1 y 1 2006 through 2011 in the partially cultivated gz1 and the undisturbed gz2 basins respectively the corresponding deposition rates in the depressions agreed well with the cs 137 records when recent changes in precipitation and land use were taken into consideration the study suggests that attention should be given to the rusle l factor when applying the rusle on karst hillslopes because of the discontinuous nature of runoff and significant underground seepage during storm events that effectively reduces the effects of slope length c 2015 elsevier b v all rights reserved

research on soil detachment rate and hydrodynamic parameters of dip anti dip slope in simulated karst trough valley bedding dip has an important influence on soil detachment and flow hydrodynamics in a karst trough valley the laboratory rainfall simulation was conducted with three bedding dips bare slope dip slope and anti dip slope under three rainfall intensities 30 60 90 mm h 1 the characteristics of soil detachment and hydrodynamic parameters were assessed including water flow shear stress stream power unit stream power and unit flow energy the significant effects of bedding dips and rainfall intensities and their interactions on soil detachment and hydrodynamic parameters were examined the results showed that 1 the soil detachment rate decreased with increasing rainfall duration and the soil detachment rate in 30 bedding dip of dip slope was much larger than those in bare slope and anti dip slope in most rainfall intensities 2 the 60 bedding dip of dip slope was the threshold that controlled the stream power unit stream power and unit flow energy increased or decreased under different rainfall intensities and 3 the soil detachment rate had extremely significant positive power relationships with water flow shear stress stream power unit stream power and unit flow energy meanwhile the stream power was the most suitable parameter for predicting soil detachment in a karst trough valley slope therefore these results could provide useful information for soil erosion prediction in a karst trough valley

the seismicity geomorphology and structural evolution of the corinth area of greece in the eastern gulf of corinth geological structure is closely reflected in the topography in the 1981 corinth earthquakes ground deformation accentuated existing geomorphological patterns we explore the relationship between seismicity and landforms in space and time the area examined extends beyond the epicentral region of the 1981 events and its evolution is traced over the last 40000 years to understand the relation between deep and superficial structures we discuss processes that occurred in the 1981 earthquakes and go on to propose that surface faulting appears only above linear faults at depth that move in earthquakes with magnitudes m s greater than six where faults at depth intersect or bend the faulting becomes distributed and prim ary faulting does not reach the surface here the surface manifestation of faulting at depth is surface folding and secondary faulting such regions are identified in maps of the eastern gulf of corinth evidence for the evolution of the fault systems is provided by eyewitness accounts of shoreline changes following the recent earthquakes historical and archaeological data pertaining to old sea levels and 14 c dates for molluscs collected from fossil shorelines the results of these studies broadly confirm an earlier view of j a jackson et al earth planet sci lett 57 377 397 1982 that motion has shifted from faulting south of the city of corinth to faulting in the perachora peninsula but the transfer is not complete areas lying between the two fault systems have moved up and down in historical and archaeological times indicating that both systems are still active the evidence for activity of the northern system points to a repeat time of 300 years for earthquakes com parable with those of 1981 the work discussed in this paper suggests that some of the features previously described as m arine terraces are fault controlled continental surfaces furtherm ore beach deposits at a num ber of different levels long regarded as successive shorelines are in fact contemporaneous the critical ages were obtained by radiocarbon dating of shell carbonate a technique which yields dependable results if applied to samples which have been carefully selected and pretreated palaeontological dating of the terraces in contrast is found to be misleading because the faunas are environm entally controlled and consequently diachronous

effects of land use land cover and rainfall regimes on the surface runoff and soil loss on karst slopes in southwest china abstract surface runoff and soil loss from 2007 to 2010 related to land use and rainfall regimes in karst hill slopes in guizhou province southwest china were analyzed using the hierarchical clustering method sixty one rainfall events under the subtropical monsoon climate condition were classified into 5 types of rainfall regimes according to the depth maximum 30 min intensity and duration of rainfall in our study we first demonstrated that the amounts of surface runoff and soil loss on the karst hill slopes were very small compared to the non karst areas because the dual hydrological structure in the karst region including ground and underground drainage systems could influence the processes of rainfall recharge and runoff generation most rainfall water was transported underground through limestone fissures and fractures while little was in the form of surface runoff second the runoff and soil loss were affected by land use management and vegetation cover soil loss was intensified in a descending order to five types of land uses pastureland burned area cropland combination vegetation land young forestland third the runoff and soil loss exhibited remarkable variances among different rainfall regimes large runoff and soil loss were mainly created by heavy rainfall storms with a rainfall depth of more than 40 mm and a maximum 30 min rainfall intensity of over 30 mm h 1 in addition rainfall storms with large antecedent precipitations could also produce large runoff and soil loss these observations indicated that limestone fissures and fractures play important roles in surface runoff generation on karst limestone slopes due to their large storage capacity and high infiltration rate lastly the soil erosion risk in the karst pure limestone slope is quite high and should be paid particular attention especially in regards to over grazing because the soil loss created by a single heavy rainstorm in pastureland was 5 times the annual soil loss tolerance

runoff and erosion processes on bare slopes in the karst rocky desertification area underground pore fissure and bedrock bareness are the main factors that lead to complicated mechanisms of soil erosion in karst regions the objectives of this study were as follows a to measure runoff and sediment generated from the surface and underground in the karst bare slope and b to analyse the impacts of underground pore fissures and bedrock bareness rates on soil erosion to achieve these objectives we designed an experiment in which underground pore fissure degrees and bedrock bareness rates were varied and their impacts on soil erosion were measured the results showed that runoff and sediment yields from the surface and underground increased with increasing rainfall intensity and the surface runoff was much more easily generated when the rainfall intensity was greater ii surface runoff yield first increased and then decreased with increasing bedrock bareness rates while the runoff yield in underground pore fissures increased with increasing bedrock bareness rates thus sediment production on the surface and in underground pore fissures showed the same pattern i e first decreased and then increased iii the surface runoff and sediment generally decreased with increasing degrees of underground pore fissures while that of underground pore fissures presented a different pattern and iv rainfall intensity bedrock bareness rates and underground pore fissure degrees were the important factors affecting soil erosion processes in karst bare slopes because the bedrock bareness rates and underground pore fissure degrees were the main factors causing the uneven distribution of runoff and sediment on soil surfaces and underground therefore soil and water loss in underground pore fissures was the special pattern and main difference in soil erosion processes in the karst region compared with other regions these results have theoretical and practical significance for understanding soil erosion mechanisms and controlling soil and water loss in karst regions

paleoseismicity of the 1981 corinth earthquake fault seismic contribution to extensional strain in central greece and implications for seismic hazard we present paleoseismological trenching results for the active skinos fault which ruptured the surface on the alkyonides gulf basin margin in the 1981 gulf of corinth earthquake sequence three trenches expose evidence of up to six previous events which are comparable to the 1981 deformation in terms of size and geometry vertical displacement produced by the 1981 earthquake ranged from 0 45 to 1 3 m at the bambakies fan trench sites decreasing towards the eastern fault tip east of the trenches trench 1 reveals two previous events with vertical displacements between 0 5 and 1 2 m since 390 a d trench 2 reveals five or six previous events but these are not dated trench 3 reveals four previous events since 670 a d vertical displacements associated with interpreted paleoearthquakes at the trench sites are 1 2 m the recurrence interval on the skinos fault is estimated to average 330 years however significant variation in recurrence interval is allowed by the available radiometric dates average vertical displacement rates derived from the trenches are in the range 0 7 2 5 mm yr a similar long term average vertical displacement rate of 1 2 2 3 mm yr is estimated for the lifespan of the basin bounding fault this equates to a horizontal seismic strain contribution of 2 5 mm yr from the skinos fault this local seismic strain rate overlaps within error with geodetically determined velocities across the alkyonides gulf assumed to represent uniform deep crustal strain thus seismic deformation on the basin bounding fault system may take up the major part of extension across the basin and aseismic strain is not necessitated by the data if correct this would imply that geodetically determined strain rates may be used as a proxy for potential seismic moment release in seismic hazard analyses for this region

geomorphic inheritance and the development of tower karst four genetic types of tower karst are identified the most typical consisting of residual hills protruding from a planed carbonate surface veneered by alluvium two extreme possibilities for tower karst evolution are recognized a direct development that is independent of any previous morphology and a sequential development that depends explicitly on the morphological characteristics of a previous cockpit karst phase examples of both are described although the latter appears the more common south china tower karst is examined in this light palaeomagnetic analysis of cave deposits in a tower near guilin indicate the feature to be a time transgressive landform four principal controls of tower development are discussed and a model of tower evolution is presented

quaternary evolution of the corinth rift and its implications for the late cenozoic evolution of the aegean summary we present geological and morphological observations at different scales to constrain rates of faulting and the distribution of deformation in the seismically active aegean region we focus first on the 130 km long corinth rift an asymmetric graben where a flight of terraces of marine origin are uplifted we show that the edges of the terraces lie in the footwall of the normal fault bounding the corinth rift and correspond to sea level highstands of laic pleistocene age using a detailed analysis of aerial and spot imagery supported by field observations we have mapped 10 terrace platforms and strandlines ranging in elevation from 10 to 400 m over distances of 2 to 20 km from the fault the elevation of the terraces inner edges was estimated at 172 sites with an error of 5m this data set contains a precise description of the uplift and flexure of 10 different palaeohorizontal lines with respect to the present sea level to date the deformation we correlate the corinth terraces with late pleistocene oxygen isotope stages of high sea level stands and with global sea level fluctuations using a thick elastic plate model consistent with our current understanding of the earthquake cycle and a boundary element technique we reproduce the geometry of the shorelines to constrain both mechanical parameters and the slip on the fault we show that the seismogenic layer behaves over the long term as if its elastic modulus were reduced by a factor of about 1000 all the terraces are fitted for fault slip increasing in proportion to terrace age and the component of regional uplift is found to be less than 0 3 mm yr 1 the best fits give a slip rate of 11 3 mm yr 1 on the main rift bounding fault over the last 350 kyr other geological and morphologic information allows us to estimate the total age of the main fault 1 ma and to examine the mechanical evolution of the corinth rift the minimum observed sediment thickness in the gulf places an extreme check on the results of the modelling and a lower bound on slip rate of 6 7 mm yr 1 40 per cent less than estimated with modelling even this slip rate is nearly 10 times higher than for comparable features in most of the aegean and elsewhere in the world at a larger scale the spacing and asymmetry of the rift systems in the aegean suggest strain localization in the upper mantle with slow extension starting 15 myr ago or earlier the more recent 1 myr rapid phase of rifting in corinth partly reactivated this earlier phase of extension the younger faulting in corinth appears to result from its present location in the inhomogeneous stress field process zone of the south westward propagating tip of the southern branch of the north anatolian fault we extend these relations to propose a mechanical model for the late cenozoic evolution of the aegean as the arabia europe collision progressed in eastern turkey it caused anatolia to move to the west and the north anatolian fault to propagate into the aegean where the early slow extension started to be modified about 5 ma ago the process of propagation dramatically increased the activity of some but not all of the earlier rifts the model we present is compatible with tectonic observations as well as with the seismicity the palaeomagnetic rotations and the displacement field now observed with gps and slr

origin of the summertime synoptic scale wave train in the western north pacific abstract the origin of the summertime synoptic wave train in the western north pacific is investigated with a multilevel nonlinear baroclinic model a realistic three dimensional summer mean state is specified and eigenvectors are calculated by introducing small perturbation initially to the model numerical experiments indicate that the origin of the synoptic wave train may arise from instability of the summer mean flow in the presence of a convection frictional convergence cfc feedback in the lack of the cfc feedback the summer mean flow supports only a least damped mode characterized by a northwest southeast oriented wave train pattern with a zonal wavelength of 2500 km in the presence of both the realistic summer mean flow and the cfc feedback the model reproduces a fast growing mode whose structure and propagation characters are similar to the observed sensitivity experiments with different initial perturbation patterns indicate that the model solution is not sensitive to initial conditions

soil structure and nutrient contents in underground fissures in a rock mantled slope in the karst rocky desertification area near surface karst fissures are filled with soils these soils are often derived from the erosion and transport of surface soil but have different properties than the surface soil in karst rocky desertification regions this study was undertaken to determine the soil structure and nutrient contents in underground fissures with different grades of rocky desertification no potential mild moderate and severe based on field surveys near surface karst fissures were selected in a typical karst plateau area soil particle compositions particularly nutrient characteristics were determined through field sampling and laboratory experiments the results indicated that the higher the rock desertification grade was the higher the soil sand 0 02 2 mm content and the lower the clay 0 002 mm content the soil in both limestone and dolomite fissures was basically neutral to weakly alkaline the surface soil in dolomite fissures presented a higher soil organic matter content than that in limestone fissures but the opposite was true for the subsurface soil from the surface to the lower layer the total nitrogen content generally decreased and the total phosphorus content generally decreased in dolomite fissures but exhibited a more complex pattern in limestone fissures the total phosphorus content of the surface soil was higher than that of the subsurface soil but the total potassium content was lower there was no significant difference among different soil layers near surface fissures are a good place to promote vegetation restoration projects because they provide good soil structure and nutritional conditions for plant growth

influence of bare rocks on surrounding soil moisture in the karst rocky desertification regions under drought conditions abstract a large number of bare rocks exposed in the field represent one of the most spectacular scenes of the karst rocky desertification krd process the presence of bare rocks modifies the microenvironment an understanding of soil moisture variability is necessary to characterize the linkages between a region s hydrology ecology and physiography the objective of the study was to determine the influence of those exposed bare rocks on soil moisture in the surrounding area in a typical krd region the forest station of sandoqing in fu yuan county yun nan province southwest china dynamic soil moisture was quantified in feb 2010 during an extreme drought period results showed that during the drought period soil moisture on the north side of the rocks was significantly higher than those on the east west and south sides p

normal faulting and crustal deformation alkyonides gulf and perachora peninsula eastern gulf of corinth rift greece geophysical structural geochronological and geomorphological data indicate that the psatha east alkyonides skinos and pisia faults are holocene active structures whereas the status of the west alkyonides strava perachora and loutraki faults is less certain we see no evidence for significant lateral surface fault growth new data for late pleistocene footwall uplift of the psatha fault are comparable with previously estimated holocene rates pre holocene stratigraphic sequences in the alkyonides gulf allow calculation of vertical displacement on the skinos fault of 1 42 1 60 km over a period of 0 6 ma previous palaeoseismological studies indicate comparable displacement rates extrapolated to 0 61 2 20 ma whereas extrapolation of previous geodetic data indicate a range of 0 17 0 46 ma the latter is too short given the evidence of the stratigraphic record signifying either that these data may not be representative of longer term rates or that significant deformation has taken place elsewhere for example on offshore antithetic faults a case is established for uniform late quaternary post mis 7 uplift of the perachora peninsula at rates of c 0 2 0 3 mm a 1 the lack of regional tilting over perachora corinth isthmia is in marked contrast to the situation in the alkyonides megara basins to the east

geometric morphology and soil properties of shallow karst fissures in an area of karst rocky desertification in sw china abstract serious soil erosion and an extremely low rate of soil formation leads to a thin layer of surface soil that makes tree growth difficult in areas of karst meanwhile surface soil driven by runoff enters shallow karst fissures skfs these skfs filled with soil have become the major habitat type in the area here we explore the morphological characteristics of shallow karst fissures as well as the soil physical and chemical properties of the skfs and comprehensively analyse the factors that influence the soil properties three key results are presented first a high heterogeneity of morphological characteristics exists for shallow karst fissures according to the different characteristics of the vertical section the skfs can be divided into 5 types these types are rectangle type pyramid type funnel type net type and diamond type in addition the skf dip angles were mainly between 60 and 90 76 39 the width of the top aperture was mainly between 20 and 40 cm 51 39 and the trace lengths were mainly between 80 and 160 cm 76 39 second compared with their characteristics of surface soil the bulk density and fractal dimension of soil particles of the skfs were both large and the main composition of the skf soil was clay third the soil nutrients of the skfs the organic matter total nitrogen and total phosphorus were lower than the surface soil nutrients but not significantly so the total potassium tk of the skfs was greater than that observed for the surface and increased as the depth of the skf increased the soil nutrients of the skfs were significantly affected by the fissure morphology the poorly connected fissures had better soil fertility when the morphological characteristics and soil properties of the skfs were comprehensively considered the vegetation types that were determined to be the best for use in the ecological restoration of areas of karst rocky desertification were deep rooted plants with especially strong root penetration the result of this study can supply some reference for future studies of karst rocky desertification control and vegetation restoration in the karst area of southwest china in the south claw silicon island in yogyakarta province indonesia and in other karst regions with the same ecological background

geodetic estimate of seismic hazard in the gulf of korinthos the recent 15 june 1995 m0 6 0 1018 n m aigion earthquake in the western gulf of korinthos has focussed attention on the seismic hazard of the region although there have been few large earthquakes in the region during this century the historical record suggests that there may have been many large earthquakes there in the interval 1750 1900 we present geodetic data that give estimates of the rate of extension of the gulf of korinthos during this century and which suggest that less than half of the elastic strain in the central and western gulf of korinthos has been released by earthquakes during this century in contrast the seismic and geodetic strains in the eastern gulf of korinthos are in agreement with each other if the discrepancy between seismic and geodetic strains in the western gulf of korinthos that has accumulated during this century is removed in earthquakes the moment release will be equivalent to several ms 6 5 earthquakes

effect of microrelief on water erosion and their changes during rainfall soil surface roughness contains two elementary forms depressions and mounds which affect water flow on the surface differently while depressions serve as temporary water storage mounds divert water away from their local summits although roughness impacts on runoff and sediment production have been studied almost no studies have been designed explicitly to quantify the evolution of depressions and mounds and how this impacts runoff generation and sediment delivery the objectives of this study were to analyze how different surface forms affect runoff and sediment delivery and to measure the changes in surface depressions and mounds during rainfall events a smooth surface was used as the control both mounds and depressions delayed the runoff initiating time but to differing degrees and slightly reduced surface runoff when compared to the runoff process from the smooth surface surface mounds significantly increased sediment delivery whilst depressions provided surface storage and hence reduced sediment delivery however as rainfall continued and rainfall intensity increased the depression effect on runoff and erosion gradually decreased and produced even higher sediment delivery than the smooth surface depressions and mounds also impacted the particle size distribution of the discharged sediments many more sand sized particles were transported from the surface with mounds than with depressions the morphology of mounds and depressions changed significantly due to rainfall but to different extents the difference in change had a spatial scale effect i e erosion from each mound contributed to its own morphological change while sediments deposited in a depression came from a runoff contributing area above the depression hence a much greater source area than a single mound the results provide a mechanistic understanding of how soil roughness affects runoff and sediment production copyright 2015 john wiley sons ltd

comparison of surface slip and focal mechanism slip data along normal faults an example from the eastern gulf of corinth greece abstract focal mechanism and surface slip data are used to investigate whether kinematics are similar at depth and at the surface along an active normal fault in the gulf of corinth greece we present a new database of slip data from the lateral termination of the south alkyonides fault segment safs and the en echelon stepover between it and an adjacent fault and use published data on surface slip and focal mechanism data pertaining to slip at depth during the 1981 alkyonides earthquake sequence the focal mechanisms exhibit similar fault plane orientations and kinematics to those measured at the surface within the stepover both data sets show that contemporaneous c n s and c e w extension is being accommodated by c e w and c n s oriented normal faults and the overall deformation is distributed oblate vertical flattening the deviation of the surface slip direction from 350 increases with distance from the centre of the safs the deviation of the focal mechanism t axes from 350 fit well with the surface data implying that the coseismic slip on the safs at depths of 7 10 km exhibits a similar kinematic pattern as that observed at the surface our results imply that it is critical to know the along strike position of data on a fault if either focal mechanisms or surface slip are to be used to infer regional strain and stress trajectories

the neotectonics of the aegean an alternative view minor reverse faults in widely dispersed neogene outcrops in the central aegean have led several people to suggest that the regional extension which started in the lower pliocene or earlier was interrupted by short periods of compression the durations of these postulated compressional episodes are short compared to the time scale on which convective forces acting on the base of the lithosphere can change thus possible mechanisms for driving such motions are limited in this paper we offer alternative explanations for these observations and in particular show that these apparently compressional episodes are probably not regional in extent and may not be truly compressional in origin in some places they are more likely to be a consequence of the considerable rotation that is found in extensional terranes the plio quaternary paleogeography of the central aegean is satisfactorily explained by uplift in the footwall blocks of normal faults and does not require regional compression studies of the faulting associated with recent large earthquakes suggest that the sort of microtectonic analysis which is typically carried out on small faults in surficial sediments is more likely to reflect the internal deformation of blocks bounded by major fault structures than be a reliable indicator of regional stress patterns

role of rock dip angle in runoff and soil erosion processes on dip anti dip slopes in a karst trough valley abstract due to the great difficulty of monitoring surface and underground runoff and sediment yield directly the surface and underground hydrological processes associated with soil leakage loss in karst trough valleys remain unknown the objective of this study was to analyse the role of the rock dip angle in the water and soil leakage loss processes to assess the characteristics of surface and underground runoff and soil erosion and to investigate their conversion relationships using rainfall experiments the results showed the following i at a steep rock dip angle 60 the underground runoff yield had a shorter stabilization time than the surface runoff yield and that the underground runoff coefficient of the dip slope exceeded 0 5 ii the surface sediment yield could be divided into the suspended load and the bed load and the underground sediment yield included only the suspended load on the anti dip slope the surface erosion modulus was 0 83 2 50 times the underground erosion modulus iii the surface and underground cumulative runoff was linearly correlated with the cumulative sediment yield the rock dip angle had a significant quadratic relationship with the surface and underground runoff and sediment yield these results improve the understanding of the surface underground runoff and soil erosion processes and have significance for preventing water and soil leakage loss on the slopes of karst trough valleys

assessing soil erosion in mediterranean karst landscapes of lebanon using remote sensing and gis abstract maps showing the potential for soil erosion at 1 100 000 scale are produced in a study area within lebanon that can be used for evaluating erosion of mediterranean karstic terrain with two different sets of impact factors built into an erosion model the first set of factors is soil erodibility morphology land cover use and rainfall erosivity the second is obtained by the first adding a fifth factor rock infiltration high infiltration can reflect high recharge therefore decreasing the potential of surface runoff and hence the quantity of transported materials infiltration is derived as a function of lithology lineament density karstification and drainage density all of which can be easily extracted from satellite imagery the influence of these factors is assessed by a weight rate approach sharing similarities between quantitative and qualitative methods and depending on pair wise comparison matrix the main outcome was the production of factorial maps and erosion susceptibility maps scale 1 100 000 spatial and attribute comparison of erosion maps indicates that the model that includes a measure of rock infiltration better represents erosion potential field investigation of rills and gullies shows 87 5 precision of the model with rock infiltration this is 17 5 greater than the precision of the model without rock infiltration these results indicate the necessity and importance of integrating information on infiltration of rock outcrops to assess soil erosion in mediterranean karst landscapes

geodetic strain of greece in the interval 1892 1992 a first order triangulation of greece was carried out in the 1890s reoccupation using global positioning system receivers of 46 of the 93 original markers yielded estimates of the deformation of the region over the intervening interval broad regions have similar geodetic strain over the 100 year time span strain north of the gulf of korinthos is predominantly north south extension though with a significant east west component the central peloponnisos is relatively stable whereas the gulfs of the southern peloponnisos are all characterized by uniaxial east west extension the seismic expression of strain for the entire region calculated from the seismic moment tensors of earthquakes of m s 5 8 during the past 100 years accounts for only 20 50 of the geodetically determined strain at a scale of 50 100 km the fraction of the strain that is expressed seismically varies much more than this range in particular whereas seismic strain in the eastern gulf of korinthos over the past 100 years is commensurate with the geodetic strain there is rapid extension across the western gulf of korinthos 0 3 strain yr 1 with negligible seismic strain for the 100 year period prior to 1992 the egion earthquake of june 1995 in the western gulf of korinthos released only a small proportion 20 of the elastic strain that had accumulated in that region the observed distribution of displacements can be explained by the relative rotation of two plates with a broad accommodation zone between them but it is equally consistent with the deformation that would be expected of a sheet of fluid moving toward a low pressure boundary at the hellenic trench a simple calculation implies that if the region does behave as a fluid then its effective viscosity is 10 22 10 23 pa s such viscosities are consistent with the deformation of a lithosphere obeying a rheological law similar to that obtained for olivine in the laboratory

spatial distribution of rock fragments on steep hillslopes in karst region of northwest guangxi china abstract rock fragments 5 mm in diameter at the soil surface and within the topsoil have a large effect on the intensity of various hydrologic and geomorphic processes however little information is available on the spatial distribution of rock fragments in subtropical regions the objective of this paper was to investigate the relationship between the spatial distribution of rock fragments and landforms on two different steep karst hillslopes in northwest guangxi southwest china on the first hillslope a disintegrated landslide failure with the presence of several large rock outcrops 2 m in height the spatial distribution of rock fragment cover had no obvious relationship with topographic position except that the mean cover percentage of small rock fragments 5 20 mm decreased from bottom to top on the second hillslope an avalanche slope without the presence of large rock outcrops the mean total rock fragment cover 5 600 mm increased from bottom 5 to top 21 with decreasing variability and rock fragments with various sizes 5 20 20 75 and 75 250 mm showed a similar increasing trend the mean total rock fragment cover increased linearly with slope gradient on the second hillslope and tended to increase and then decrease with gradient but their relationship was not obvious on the first hillslope this indicated that the spatial distribution of surface rock fragment cover had a close relationship with the presence of large rock outcrops and slope gradient however the median diameter d50 of the surface rock fragments had an increase decrease trend with slope gradient but there was no obvious relationship on both hillslopes with low overland flow therefore the dominant factor for the spatial distribution of rock fragment cover and size at the soil surface might not be soil erosion by water but slope gradient vegetation and geomorphologic condition of the slope the mean total volumetric rock fragment content 5 250 mm within the topsoil 10 20 cm thick increased linearly from bottom 16 to top 39 with slope gradient on the first hillslope and had a logarithmic increase from bottom 10 to top 27 with gradient on the second hillslope this suggested that rock fragment content within the topsoil was mostly controlled by slope gradient and topographic positions and had not a close relationship with the presence of large rock outcrops

superficial and subterranean soil erosion in tabasco tropical mexico development of a decision tree modeling approach tropical countries suffer from a lack of financial resources to monitor and model sources and outcomes of soil degradation and therefore a scarcity of data in this study it was tried to model superficial and subterranean water erosion based on basic environmental variables such as geological formation soil type or vegetation cover data which are potentially available even in developing countries different forms of water erosion and karst or pseudokarst formations in tabasco southeastern mexico were estimated the study region 3500 km 2 consists of plain and hilly areas with an annual precipitation ranging from 2000 to 4000 mm main land use form is rangeland the area is geologically composed of sedimentary rocks limestone sandstone and conglomerates collecting data by field observations over the entire study area a cartography of different soil loss forms such as rill and gully erosion mass movement sinkholes and tunnels was created including field data from available maps of geological formation soil type precipitation and former land use 20 years ago additionally data collected in the field such as actual land use vegetation cover and inclination were added in the entire study area 1039 sites were affected by soil erosion with 2435 single manifestations of soil erosion 482 sites were found with one gully each 57 sites with erosion rills with a total of 416 392 sites with one mass movement each 85 sites with sinkholes with a total of 1122 and 23 sites with one tunnel each rendzic leptosols over oligocene limestone are strongly affected by sinkholes and tunnels in regions with inclinations of less than 5 this phenomenon is explained by karstic and pseudokarstic formation superficial erosion forms are mainly found on rendzic leptosols over shale sandstone and on eutric or peli eutric vertisols on andesit in areas with inclinations between 5 and 30 the application of classification trees allowed to successfully predict the occurrence of sinkholes and tunnels degree of agreement between prediction and observation very good to excellent even in areas with scarce data bases this could allow for easy identification of high risk areas predictive success of the occurrence of the different forms of superficial soil losses however is low superficial erosion seems to be mainly caused by more specific pedological factors nevertheless automated induction of classification trees can be a valuable tool for preliminary data analysis and hypothesis generation in areas with lack of local expertise and can guide erosion risk mapping and soil conservation planning 2007 elsevier b v all rights reserved

the ad 365 crete earthquake and possible seismic clustering during the fourth to sixth centuries ad in the eastern mediterranean a review of historical and archaeological data abstract historical and archaeological data are used to test geological claims that in the fourth to sixth centuries ad the eastern mediterranean experienced an unusual clustering of destructive earthquakes the early byzantine tectonic paroxsym a review of historical accounts of a notable earthquake at this time that of 21 july ad 365 indicates that this event destroyed nearly all the towns in crete and was followed by a tsunami which devastated the nile delta the ad 365 event was also probably responsible for reported or observed destruction in ancient towns of west cyprus and libya this earthquake is most likely to be identified with a hellenic arc subduction zone event of great m 8 magnitude as testified by up to 9 m of uplift in western crete dated by previous geological studies to around this time historical and archaeological data also support the hypothesis that the fourth to sixth centuries ad was a period of abnormally high seismicity in the eastern mediterranean the high seismicity rates of this period may reflect a reactivation of all plate boundaries in the region dead sea transform east anatolian fault north anatolian fault hellenic arc cyprus arc fault

the evolution of the gulf of corinth greece an aftershock study of the 1981 earthquakes summary a preliminary study of the aftershocks of three earthquakes that occurred near to corinth greece in 1981 is combined with observations of the morphology and faulting to understand the evolution of the eastern gulf of corinth the well located aftershocks form a zone 60km long and 20km wide they do not lie on the main fault planes and are mostly located between the north dipping faulting on which the first two earthquakes occurred and the south dipping faulting associated with the third event a cluster of aftershocks also lies in the footwall of the eastern end of the south dipping fault of the third event morphologically it is observed that in the evolution of the eastern gulf of corinth antithetic faulting apparently predates the appearance of the main faulting at the surface this evolution can be explained by motion on a deep seated shallow angle aseismic normal fault a model based on such a fault also accounts for the aftershock distribution of the 1981 earthquakes

controls of infiltration runoff processes in mediterranean karst rangelands in se spain semiarid karst landscapes represent an important ecosystem surrounding the mediterranean basin for which little is known on runoff generation knowledge of the sources and patterns of variation in infiltration runoff processes and their controls is important for understanding and modelling the hydrological functions of such ecosystems the objectives of this paper are to determine the infiltration rates and their controls in a representative mountain karst area sierra de gador se spain at micro plots and to investigate the integrated response of rainfall on a typical hillslope rainfall simulations in micro plots and natural rainfall runoff monitoring on a hillslope were carried out complementarily we investigated the role of soil surface components vegetation rock outcrop fracture and soil crust topographic position antecedent soil moisture and rainfall characteristics in regulating infiltration runoff processes results of rainfall simulation revealed the importance of vegetation cover and the presence of rock fractures in promoting the infiltration in the limestone karst landscape while bare patches and rock outcrops acted as sources for runoff all plots with 50 vegetation cover had no runoff with up to 55mmh 1 of simulated rain in contrast nearly all bare plots had runoff under the same simulated rain with runoff coefficients ranging from 3 1 to 20 6 on dry soil surface conditions and from 2 0 to 65 4 on wet soil surfaces runoff coefficients amounted to 59 0 79 5 for rock outcrops without cracks but were drastically reduced by the presence of cracks the surfaces with rock fragments resting on the soil generally located in the middle of the slopes prevented more effectively the runoff generation than those surfaces where rock fragments were embedded in the top soil antecedent soil moisture had significant impact on runoff generation with wet soil having doubled runoff coefficient shortened time to runoff and increased runoff rate compared to the same but dry soil linear regressions indicated that the main controls for constant infiltration rate were the cover percentages of vegetation and litter plus rainfall intensity while the major controls for runoff coefficient were the bare soil and vegetation coverage plus rainfall intensity high infiltration rates measured at the micro plots agreed with low intra event runoff coefficients mostly below 1 observed under natural rainfalls at the hillslope runoff depth and coefficient at the hillslope was significantly correlated with rainfall depth maximum hourly rainfall intensity and antecedent precipitation over 20days ap20 during the 1 5 year monitoring period from sep 2003 to mar 2005 the overall infiltration was 41 of the total rainfall amount and the maximum infiltration rate was almost 94 of the largest single rainfall event the results from this study contribute to improved understanding of the magnitude and controls of the surface runoff in semiarid karst mountain areas 2011 elsevier b v