hyperconcentrated flows on a forested alluvial fan of eastern canada geomorphic characteristics return period and triggering scenarios the assessment of the dominant flow type on alluvial fans usually refers to two categories debris flow fans i e sediment gravity flows and fluvial fans i e fluid gravity flows here we report the results of combined morphometric stratigraphic and sedimentological approaches which suggest that hyperconcentrated flows a transitional process rheologically distinct from debris flows and floods and sometimes referred to as debris floods mud floods or transitional debris flows are the dominant fan building process in eastern canada these flows produce transitional facies between those of debris flows which consist of a cohesive matrix supported diamicton and those of river flows which display more distinct stratification the size of the blocks in the channels and the abrasion scars at the base of several trees attest to the high transport capacity of these flows the fan channels are routed according to various obstacles comprised primarily of woody debris that impede sediment transit however these conditions of sediment storage are combined with readily available sediment due to the friable nature of the local lithology tree ring analysis allowed the reconstruction of eight hydrogeomorphic events which are characterized by a return period of 9 25 years for the period 1934 2008 although most of the analyzed events occurred after 1970 historical weather data analysis indicates that they were related to rare hydrometeorological events at regional and local scales this evidence led to the elaboration of weather scenarios likely responsible for triggering flows on the fan according to these scenarios two distinct hydrologic regimes emerge the torrential rainfall regime and the nival regime related to snowmelt processes hydrogeomorphic processes occurring in a cold temperate climate and particularly on small forested alluvial fans of north eastern north america should receive more attention from land managers given the hazard they represent as well as because of their sensitivity to various meteorological parameters copyright 2014 john wiley sons ltd

removing free surface multiples from teleseismic transmission and constructed reflection responses using reciprocity and the inverse scattering series we develop a new way to remove free surface multiples from teleseismic p transmission and constructed reflection responses we consider two types of teleseismic waves with the presence of the free surface one is the recorded waves under the real transmission geometry the other is the constructed waves under a virtual reflection geometry the theory presented is limited to 1d plane wave acoustic media but this approximation is reasonable for the teleseismic p wave problem resulting from the steep emergence angle of the wavefield using one way wavefield reciprocity we show howtheteleseismicreflectionresponsescanbereconstructed from the teleseismic transmission responses we use the inverse scattering series to remove free surface multiples from the original transmission data and from the reconstructed reflection response we derive an alternative algorithm for reconstructing the reflection response from the transmission data that is obtained by taking the difference between the teleseismic transmission waves before and after free surface multiple removal numerical tests with 1d acoustic layered earthmodelsdemonstratethevalidityofthetheorywedevelop noisetestshowsthatthealgorithmcanworkwiths nratioaslowas5comparedtoactualdatawiths nratiofrom30 to 50 testing with elastic synthetic data indicates that the acousticalgorithmisstilleffectiveforsmallincidenceangles oftypicalteleseismicwavefields

controls on fan depositional processes in the schist ranges of the southern alps new zealand and implications for debris flow hazard assessment sixteen morphometric and vegetation cover variables associated with 32 debris flow and 28 fluvial fans and their basins in the schist ranges of the southern alps of new zealand are examined the results show statistically significant differences in the area length planimetric shape relief ratio melton s ruggedness r and forest and total vegetation cover between debris flow and fluvial basins and in the apex and toe elevations area and upper and average axial gradients between debris flow and fluvial fans all of these variables except the apex and toe elevations of the fans reflect differences between debris flow and fluvial processes and environmental controls on them discriminant analysis indicates that the relief ratio and melton s r of the basin and upper and average gradients of the fan axis are able to correctly classify debris flow and fluvial fans with almost equally good results obtained by employing only a pair of variables either basin relief ratio and upper fan gradient or basin melton s r and basin shape the lower thresholds at debris flow sites and upper thresholds at fluvial sites for the relief ratio and melton s r of the basin and upper and average gradients of the fan are identified and these as well as the mean values of these variables show significant differences from fans in nearby sedimentary ranges of the southern alps with important implications for the assessment of debris flow hazard on fans fan gradient is found to be closely associated with basin size area and length at debris flow sites but with basin ruggedness relief ratio at fluvial sites both fan types show a weak association between their size and the size of the contributing basin

from gullies to mountain belts a review of sediment budgets at various scales this paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research sediments are a product of mass dispersal at the earth surface and take part in global cycles sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface this involves fundamental questions about the interplay of uplift climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion reservoir siltation and coastal protection first after introducing basic concepts relevant scales and methodologies the different components of quaternary routing systems from erosion in headwaters river systems glacial and paraglacial systems lakes deltas estuaries coasts shelves epicontinental seas and deep sea fans are discussed in terms of their sediment budget most suitable are sedimentologically closed or semi closed depositional environments e g alluvial fans lakes deltas and deep sea fans in a second step the dynamics of passive active and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings in terms of sedimentary basin types rifts intracontinental and epicontinental settings are preferred objects of sediment budgets because of their persistence and relatively simple overall sedimentary architecture however closing basins such as foreland forearc retroarc piggy back and wedge top basins may provide excellent snapshots of orogenic sediment fluxes in a third step the large long lived routing systems of the amazon the ganges brahmaputra and the rhine are reviewed for each system estimates of either sediment volumes mass or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the late glacial maximum as well as the cenozoic following lessons can be taken from these case studies i depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems ii the response times of these large systems are within the milankovich time interval thus lower than predicted from diffusion models iii cyclic routing of sediments in continental basins is much more dominated by climate human control than by eustacy and iv at long time scales ultimate sinks win over intermittent storage it is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles this includes i to better determine response times of large routing systems by linking quaternary with cenozoic sediment budgets and continental with marine sub systems ii to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems iii to study sediment partitioning at the basin scale iv to reconcile continental supply dominated sequence stratigraphy with the eustatic dominated marine concept and iv to account for non actualism of ancient systems with respect to their erosion and transport mode in particular during glaciations and pronounced arid intervals glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins thus challenging the principle of mass conservation

chronology of processes in high gradient channels of medium high mountains and their influence on the properties of alluvial fans abstract high gradient channels are the locations of the greatest geomorphological activity in medium high mountains the channels frequency and character influence the contemporary morphology and morphometry of alluvial fans there is currently no detailed information regarding the frequency of these processes in high gradient channels and the evolution of alluvial fans in medium high mountains in central europe this study in the moravskoslezske beskydy mts analysed 22 alluvial fans 10 debris flow fans and 12 fluvial fans the processes occurring on the fans were dated using dendrogeomorphological methods a total of 748 increment cores were taken from 374 trees to reconstruct 153 geomorphological process events 60 debris flow and 93 floods the frequency of the processes has been considerably increasing in the last four decades which can be related to extensive tree cutting since the 1970s processes in high gradient channels in the region affecting the alluvial fans across the mountain range are predominantly controlled by cyclonal activity during the warm periods of the year probable triggers of local events are heavy downpours in the summer in addition spring snowmelt has been identified as occasionally important this study of the relations affecting the type and frequency of the processes and their effect on the properties of alluvial fans led to the creation of a universal framework for the medium high flysch mountains of central europe the framework particularly reflects the influence of the character of hydrometeorological extremes on the frequency and type of processes and their reflection in the properties of alluvial fans

regional relief characteristics and denudation pattern of the western southern alps new zealand abstract the southern alps of new zealand are the topographic expression of active oblique continental convergence of the australian and pacific plates despite inferred high rates of tectonic and climatic forcing the pattern of differential uplift and erosion remains uncertain we use a 25 m dem to conduct a regional scale relief analysis of a 250 km long strip of the western southern alps wsa we present a preliminary map of regional erosion and denudation by overlaying mean basin relief a modelled stream power erosion index river incision rates historic landslide denudation rates and landslide density the interplay between strong tectonic and climatic forcing has led to relief production that locally attains 2 km in major catchments with mean values of 0 65 0 68 km interpolation between elevations of major catchment divides indicates potential removal of l01 103 km3 or a mean basin relief of 0 51 0 85 km in the larger catchments local relief and inferred river incision rates into bedrock are highest about 50 67 of the distance between the alpine fault and the main divide the mean regional relief variability is 0 5 km local relief valley cross sectional area and catchment width correlate moderately with catchment area and also reach maximum values between the range front and the divide hypsometric integrals show scale dependence and together with hypsometric curves are insufficient to clearly differentiate between glacial and fluvial dominated basins mean slope angle in the wsa 30 is lower where major longitudinal valleys and extensive ice cover occur and may be an insensitive measure of regional relief modal slope angle is strikingly uniform throughout the wsa 38 40 and may record adjustment to runoff and landsliding both and show non linear relationships with elevation which we attribute to dominant geomorphic process domains such as fluvial processes in low altitude valley trains surface runoff and frequent landsliding on montane hillslopes relief dampening by glaciers and rock fall avalanching on steep main divide slopes

a combined morphometric sedimentary gis and modelling analysis of flooding and debris flow hazard on a composite alluvial fan caveside tasmania abstract two episodes of intense flooding and sediment movement occurred in the westmorland stream alluvial system near caveside australia in january 2011 and june 2016 the events were investigated in order to better understand the drivers and functioning of this composite alluvial system on a larger scale so as to provide awareness of the potential hazard from future flood and debris flow events a novel combination of methods was employed including field surveys catchment morphometry gis mapping from lidar and aerial imagery and hydraulic modelling using riverflow 2d software both events were initiated by extreme rainfall events

morphometric controls and geomorphic responses on fans in the southern alps new zealand morphometric variables associated with 41 debris ow and 18 uvial fans and their basins in the southern alps of new zealand are examined the results show statistically signi cant differences in the area maximum elevation relief and ruggedness melton s r of the basin and the area gradient and apex and toe elevations of the fan between debris ow and uvial sites concavity of the fan longitudinal pro le also differs between the two fan types although this could not be tested statistically most of these morphometric differences re ect differences in processes and environmental controls on them discriminant analysis indicates that basin area and fan gradient best differentiate the two fan types by process moderately strong correlations exist on both debris ow and uvial fans between basin area or melton s r and fan area correlations between basin area or melton s r and fan gradient are generally weaker the results of this study also indicate that on debris ow prone fans the fan gradient and basin melton s r have lower thresholds which overlap little with upper thresholds associated with basins where only stream ow reaches the fan these thresholds may therefore have value in preliminary morphometric assessments of debris ow hazard on fans in the southern alps copyright 2004 john wiley sons ltd

dendrogeomorphic approaches for identifying the probable occurrence of debris flows and related torrential processes in steep headwater catchments the hrubý jesenik mountains czech republic abstract culminating parts of mid mountain ranges in central europe are interwoven by a network of high gradient streams these parts together with the surrounding slopes form a coupling system in which hazardous geomorphic processes such as landslides debris flows or flash floods can occur in the case of the hrub jesenik mountains eastern sudetes czech republic we present an evaluation of the debris flows and related torrential processes in the high gradient streams of the selected catchment based on dendrogeomorphic methods in addition to the classical dendrogeomorphic approaches we refined the procedure of identifying certain and probable events using new weighted indexes for event reconstruction additionally because of the steep narrow channels without a characteristic accumulation cone a new spatial approach is defined based on the spacing of disturbed trees for each event random distribution or clustering and location of disturbed trees in an individual section of the valley floor using kernel density analysis for each event and calculating the particular grids in arcgis software we are able to describe the spatial reach and probable nature of an event debris flow or hyperconcentrated flow dendrogeomorphic analysis of 397 sampled trees predominantly coniferous trees revealed 24 torrential events 15 certain nine probable since 1928 with peaks in 1991 1997 and 2010 according to index values in addition the spatial distribution of disturbed trees grouped in clusters in these years indicates debris flow events in the upper parts of the catchment it seems that new dendrogeomorphic approaches should be valuable in remote steep headwater catchments where several types of processes affect the valley floors

debris flow hazards on tributary junction fans chitral hindu kush range northern pakistan abstract the chitral district of northern pakistan lies in the eastern hindu kush range the population in this high relief mountainous terrain is restricted to tributary junction fans in the chitral valley proximity to steep valley slopes renders these fans prone to hydrogeomorphic hazards including landslides floods and debris flows this paper focuses on debris flow hazards on tributary junction fans in chitral using field observations satellite image analyses and a preliminary morphometry the tributary junction fans in the chitral valley are classified into 1 discrete and 2 composite the discrete fans are modern day active landforms and include debris cones associated with ephemeral gullies debris fans associated with ephemeral channels and alluvial fans formed by perennial streams the composite fans are a collage of sediment deposits of widely different ages and formed by diverse alluvial fan forming processes these include fans formed predominantly during mis 2 holocene interglacial stages superimposed by modern day alluvial and debris fans composite fans are turned into relict fans when entrenched by modern day perennial streams these deeply incised channels discharge their sediment load directly into the trunk river without significant spread on fan surface in comparison when associated with ephemeral streams active debris fans develop directly at composite fan surfaces major settlements in chitral are located on composite fans as they provide large tracts of leveled land with easy accesses to water from the tributary streams these fan surfaces are relatively more stable especially when they are entrenched by perennial streams e g chitral ayun and reshun when associated with ephemeral streams e g snowghar or a combination of ephemeral and perennial streams e g drosh these fans are subject to frequent debris flow hazards fans associated with ephemeral streams are prone to high frequency 10 years return period debris flow hazards by comparison fans associated with perennial streams are impacted by debris flow hazards during exceptionally large events with return periods of 30 years this study has utility for quick debris flow hazard assessment in high relief mountainous regions especially in arid to semi arid south central asia where hazard zonation maps are generally lacking

topographic predictors of susceptibility to alluvial fan flooding southern apennines the flooding susceptibility of alluvial fans in the southern apennines has long been neglected to partly address this oversight we focus on the region of campania which contains highly urbanized piedmont areas particularly vulnerable to flooding our findings are based on stratigraphic analysis of the fans and morphometric analysis of the basin fan systems using geomorphological analysis we recognized active alluvial fans while stratigraphic analysis together with statistical analysis of the morphometric variables was used to classify the fans in terms of the transport process involved the results indicate that in the geological context examined the best discrimination between debris flow df and water flood wf processes is achieved by means of two related variables one for the basin feeder channel inclination cg and one for the fan fan length fl the probability that an unclassified fan belongs to group wf is computed by applying a logistic function in which a p value exceeding 0 5 indicates that a basin fan system belongs to group wf this important result led to the classification of the entire basin fan system data as regards process intensity debris flow dominated fans are susceptible to the occurrence of flows with high viscosity and hence subject to more severe events than water flood dominated fans bearing this in mind the data gathered in this study allow us to detect where alluvial fan flooding might occur and give information on the different degrees of susceptibility at a regional scale regrettably urban development in recent decades has failed to take the presence of such alluvial fans into account due to the long recurrence time 50 100 years between floods this paper outlines the distribution of such susceptibility scenarios throughout the region thereby constituting an initial step to implementing alluvial fan flooding control and mitigation copyright 2012 john wiley sons ltd

effects of large deep seated landslides on hillslope morphology western southern alps new zealand 1 morphometric analysis and air photo interpretation highlight geomorphic imprints of large landslides i e affecting 1 km2 on hillslopes in the western southern alps wsa new zealand large landslides attain kilometer scale runout affect 50 of total basin relief and in 70 are slope clearing and thus relief limiting landslide terrain shows lower mean local relief relief variability slope angles steepness and concavity than surrounding terrain measuring mean slope angle smoothes out local landslide morphology masking any relationship between large landslides and possible threshold hillslopes large failures also occurred on low gradient slopes indicating persistent low frequency high magnitude hillslope adjustment independent of fluvial bedrock incision at the basin and hillslope scale slope area plots partly constrain the effects of landslides on geomorphic process regimes landslide imprints gradually blend with relief characteristics at orogen scale 102 km while being sensitive to length scales of slope failure topography sampling and digital elevation model resolution this limits means of automated detection and underlines the importance of local morphologic contrasts for detecting large landslides in the wsa landslide controls on low order drainage include divide lowering and shifting formation of headwater basins and hanging valleys and stream piracy volumes typically mobilized yet still stored in numerous deposits despite high denudation rates are 107 m3 and theoretically equal to 102 years of basin wide debris production from historic shallow landslides lack of absolute ages precludes further estimates deposit size and mature forest cover indicate residence times of 101 104 years on these timescales large landslides require further attention in landscape evolution models of tectonically active orogens

catchment scale weathering fluxes in the southern alps new zealand abstract the dissolved and suspended sediment flux in a small headwater in the southern alps new zealand over a 16 month period showed that mass transferred as dissolved load 91 t km 2 a 1 is a significant flux relative to the suspended sediment flux 210 t km 2 a 1 export of dissolved load occurs mostly under baseflow with 268 t being transported over 10 discrete events relative to a total load of 1171 t over the experimental observation period which is equivalent to 23 of the ionic flux occurring during event flow storm events contribute 2420 t of suspended sediment accounting for 90 of the total suspended sediment flux the chemical weathering flux was 43 of the physical weathering flux and much higher than previous estimates of 1 9 for the southern alps such a high relative rate of chemical weathering is unlikely to be indicative of the full southern alps extent but suggests that in some regions of the eastern southern alps mass loss via chemical weathering may be a significant portion of overall flux during storm events temporal exhaustion of sediment occurred and inferred limited sediment source production rather than limited connectivity with the hillslope environment similar supply limitation is expressed in the ionic flux where rainfall events do not usually express hysteretic behaviour and event flow is dominated by a simple dilution recession

comparison of logistic regression and neural network models in assessing geomorphic control on alluvial fan depositional processes calabria southern italy at the outlet of steep catchments depositional processes ranging from stream flow to debris flow usually lead to alluvial fan development apart from geological and tectonic factors controlling basin sediment availability several authors highlighted the control role of basin fan morphometry on fan sedimentary processes in this framework the paper was aimed to identify the feeder basin variables that can best differentiate fan processes in southern italy to evaluate the effect of the statistical method on variable selection we compared logistic regression lr and artificial neural network ann the latter not commonly used in fan studies alluvial fans were mapped at the mouth of steep v shaped valleys dissecting the tyrrhenian coast of northern calabria where crystalline metamorphic and subordinate carbonate rocks crop out fans were classified through field survey into two groups those with f1 and those without f0 any debris flow evidence morphometric variables were derived for each basin fan system percentage of lithological units cropping out in the catchments was also considered non parametric statistics revealed that f0 and f1 significantly differ in fan size area perimeter and length main channel slope lowermost valley width melton s number and geologic index the relationships between morphometric variables were stronger for f0 than f1 the lr and ann highlighted the primary control of basin lithology on fan dynamics followed by basin mean slope although ann outperformed lr in model calibration both the approaches correctly classified most of the validation samples 87 alluvial fans with unknown depositional process were classified as belonging to the same group

imaging the earth with passive seismic arrays earthquake and exploration seismology share a common foundation in elastic wave propagation most of what we know about earthquakes is known from the elastic waves they emit while seismic methods in exploration are all about using scattered elastic waves to image earth structure seismologists have been using elastic waves to probe the earth since the very earliest instruments after all it was early seismic measurements that led to the spherical shell model of earth structure crust mantle and core taught to grade school students

geomorphology and forest management in new zealand s erodible steeplands an overview abstract in this paper we outline how geomorphological understanding has underpinned forest management in new zealand s erodible steeplands where it contributes to current forest management and suggest where it will be of value in the future we focus on the highly erodible soft rock hill country of the east coast region of north island but cover other parts of new zealand where appropriate we conclude that forestry will continue to make a significant contribution to new zealand s economy but several issues need to be addressed the most pressing concerns are the incidence of post harvest storm initiated landslides and debris flows arising from steepland forests following timber harvesting there are three areas where geomorphological information and understanding are required to support the forest industry development of an improved national erosion susceptibility classification to support a new national standard for plantation forestry terrain analysis to support improved hazard and risk assessment at detailed operational scales and understanding of post harvest shallow landslide debris flows including their prediction and management

gis morphometric indicators for the analysis of sediment dynamics in mountain basins watershed management and headwater reconstruction programs require a reliable knowledge of sediment dynamics geographical information systems gis provide the framework for the implementation of different complex techniques for the assessment of shallow landsliding and erosion processes in mountain basins this paper presents some morphometric indicators aimed at erosion and sediment delivery analysis the proposed indicators can be easily derived from medium to fine resolution digital elevation models dem applications conducted in eastern italian alps have shown the adequateness of the proposed approach to address erosion and sediment related problems the analysis considered the classification of sediment source areas with regard to their activity the comparison between drainage basins having different morphological characteristics and the topographic control on sediment transport capacity with a particular attention to the identification of channel reaches characterised by a low sediment transport capacity

the removal of free surface interactions from three component seismograms summary the effect of the free surface can be removed from three component seismic recordings to recover the incident upgoing wavefield if the slowness and azimuth of the current wavefront are known as a function of time for a single threecomponent station it is usually possible to estimate an azimuth for an event from the first arriving p waves but slowness estimates are less reliable when more than one wavetype is presented in the seismic wavetrain however the free surface correction operators are generally slowly varying functions of slowness and so some error in slowness can be tolerated effective approximations for the removal of the free surface effects can be made for hard rock sites to cover slowness bands for the main regional phases pn pg sn and lg by applying these operators in turn over group velocity windows appropriate to the particular phases the relative amplitude of the p sv and sh contributions to the wavefield can be estimated because the free surface amplification effects have been removed the amplitudes can be compared directly and provide useful constraints on the radiation characteristics of the source this procedure is therefore helpful for developing discrimination measures for different classes of sources

radiocarbon constraints on the holocene flood deposits of the ning zhen mountains lower yangtze river area of china lying athwart both the temperate and subtropical zones the ning zhen mountains are particularly prone to extreme floods in the summer months when cold fronts collide with the subtropics derived warm airmasses the holocene flood deposits in the region may provide a long term perspective on hydrographical change and its palaeoclimatic implications radiocarbon dates on carbonised wood preserved in flooding sediments reveal that the region has experienced a number of catastrophic floods throughout the middle holocene these extreme flooding events cluster into three periods i 9200 8200 cal yr bp ii 7600 5800 cal yr bp and iii 5200 4000 cal yr bp corresponding to the times when the east asian monsoon has been intensified under warm conditions the significant falls in flooding frequency around 8200 cal yr bp 5800 cal yr bp and 4000 cal yr bp may have resulted from substantial reduction in regional precipitation probably associated with meridional displacement of the planetary frontal system copyright c 2003 john wiley sons ltd less

a new hierarchical bayesian approach to analyse environmental and climatic influences on debris flow occurrence abstract how can debris flow occurrences be modelled at regional scale and take both environmental and climatic conditions into account and of the two which has the most influence on debris flow activity in this paper we try to answer these questions with an innovative bayesian hierarchical probabilistic model that simultaneously accounts for how debris flows respond to environmental and climatic variables in it full decomposition of space and time effects in occurrence probabilities is assumed revealing an environmental and a climatic trend shared by all years catchments respectively clearly distinguished from residual random effects the resulting regional and annual occurrence probabilities evaluated as functions of the covariates make it possible to weight the respective contribution of the different terms and more generally to check the model performances at different spatio temporal scales after suitable validation the model can be used to make predictions at undocumented sites and could be used in further studies for predictions under future climate conditions also the bayesian paradigm easily copes with missing data thus making it possible to account for events that may have been missed during surveys as a case study we extract 124 debris flow event triggered between 1970 and 2005 in 27 catchments located in the french alps from the french national natural hazard survey and model their variability of occurrence considering environmental and climatic predictors at the same time we document the environmental characteristics of each debris flow catchment morphometry lithology land cover and the presence of permafrost we also compute 15 climate variables including mean temperature and precipitation between may and october and the number of rainy days with daily cumulative rainfall greater than 10 15 20 25 30 40 mm day 1 application of our model shows that the combination of environmental and climatic predictors explained 77 of the overall variability of debris flow occurrences in this data set occurrence probabilities depend mainly on climatic variables which explain 44 of the overall variability through the number of rainy days and maximum daily temperature this important time component in the variability of overall debris flow occurrence is shown to be responsible for a significant increase in debris flow activity between 1970 and 2005 at regional scale environmental variables which account for 33 of the overall variability includes mostly the morphometric variables of the debris flow catchments

a frost buzzsaw mechanism for erosion of the eastern southern alps new zealand article in the southern alps new zealand large gradients in precipitation b 1t o 12 m year 1 and rock uplift b 1t o 10 mm year 1 produce distinct post glacial geomorphic domains in which landslide driven sediment production dominates in the wet rapid uplift western region and rockfall controls erosion in the drier low uplift eastern region because the western region accounts for b25 of the active orogen the dynamics of erosion in the extensive eastern region are of equal importance in estimating the relative balance of uplift and erosion across the southern alps here we assess the efficacy of frost cracking as the primary rockfall mechanism in the eastern southern alps using air photo and topographic analysis of scree slopes cosmogenic radionuclide dating of headwalls paleo climate data and a numerical model of headwall temperature currently active scree slopes occur at a relatively uniform mean elevation 1450 m and their distribution is independent of hillslope aspect and rock type consistent with the notion that frost cracking which is maximized between 3 and 8 c may control rockfall erosion headwall erosion rates of 0 3 to 0 9 mm year 1 measured using in situ 10 be and 26 al in the cragieburn range confirm that rockfall erosion is active in the late holocene at rates that roughly balance rock uplift models of the predicted depth of frost activity are consistent with the scale of fractures and scree blocks in our field sites also vegetated paleo scree slopes are ubiquitous at elevations lower than active scree slopes consistent with the notion that lower temperatures during the last glacial advance induced pervasive rockfall erosion due to frost cracking our modeling suggests temporally averaged peak frost cracking intensity occurs at 2300 m a s l the approximate elevation of the highest peaks in the central southern alps suggesting that the height of these peaks may be limited by a frost buzzsaw

book reviewseismic migration imaging of acoustic energy by wavefield extrapolation a theoretical aspects a j berkhout developments in solid earth geophysics 14a elsevier amsterdam 1982 2nd revised

geomorphological controls on soil fertility of semi arid alluvial fans a case study of the joghatay mountains northeast iran abstract alluvial fans are ideal locations to examine the effect of geomorphic processes and landforms on the soil characteristics the rate of soil development and fertility differs between active surfaces exposed to aggradation and old or relict surfaces subject to degradation the aim of this research is to evaluate the effect of landforms and processes on soil fertility based on the studies on three alluvial fans of different ages relict old and young a total of 36 soil samples were collected from these three alluvial fan surfaces the samples were gathered from different locations of fans apex and toe and landforms gully beds interfluves swales and bars and for each sample nine variables including soil texture acidity ph electrical conductivity ec total neutralizing value tnv available phosphorus ap available potassium ak total nitrogen tn total organic carbon toc and hydraulic conductivity k were measured the results show that the values of tnv ap ak tn and toc increase as clay increases in the relict and old fans the values of tnv toc tn ap ak clay and silt are higher in the interfluves than in the gully beds also in the relict and old fans the rates of clay silt toc tn and ap are higher in the apexes than in the toes in the young fan the values of most variables are higher in the toe compared to the apex the wide and relatively flat interfluves of the apex of old and relict fans have soils that are more fertile compared to the extensively entrenched surfaces of relict and old fan toes with relatively steep sloped interfluves the less fertile soils in the apex of young fan can be attributed to its coarse textured soils and also to repeated flooding and depositional processes overall this study reveals that geomorphological landforms and processes such as aggradation and degradation play an important role in the spatial variation of soil fertility