the red soils their origin properties use and management in greece abstract red soils in greece are distributed thoughout the country but they occur more frequently in the southern provinces and constitute important soil resources supporting several land utilization types they can be grouped into two categories the autochthonous and the allochthonous the former soils are found on hard limestone and on basic igneous rocks in sloping mountainous or hilly landscapes moreover they can be found on mica schists and gneisses in locations adjacent to marble or calcareous mica schists allochthonous red soils are wide spread on late tertiary and pleistocene surfaces in the lowlands many of these deep deposits have red strata a few decimeters to several meters thick or red colored and fine textured layers interbedded with light colored deposits of marl or conglomernates and also with thick strata enriched with calcareous concretions they are distributed in the thermo and meso mediterranean bioclimatic zones these sites have a common feature the gently sloping terrain that ensures efficient drainage there are some differences in chemical and physical properties and in the clay mineralogy of the two groups of greek red soils palygorskite is present in some soils developed on basic rocks the clay minerals of the allochthonous soils on pleistocene and late pliocene seems to be mixed with micas in significant amounts soil forming factors required for the formation of red soils are a parent material containing iron bearing minerals and rich in bases b slope gradients and or water permeabilities of the bed rock securring excessive drainage and c vegetation cover that does not produce high amounts of and deeply distributed organic matter the allochthonous red soils have likely inherited their color from their parent materials that were transported from the originally formed residual soils on hard limestone the soils retain the red color in the thermo mediterranean zone only on sloping terrains the soils on these landscapes are frequently stratified the greek red soils belong to the great groups of rhodoxeralfs palexeralfs xerochrepts orthents large portions of the allochthnous soils have been desertified or have been severely degraded and their extensive exploitation is not recommended soil management practices applied in the allochthnous soils include erosion control preservation of organic matter minimum tillage split application of nitrogen using non acidifying fertilizers irrigation soil water conservation and sheltered agriculture

macroporosity and infiltration in blanket peat the implications of tension disc infiltrometer measurements little is known about the processes of infiltration and water movement in the upper layers of blanket peat a tension infiltrometer was used to measure hydraulic conductivity in a blanket peat in the north pennines england measurements were taken from the surface down to 20 cm in depth for peat under four different vegetation covers it was found that macropore flow is a significant pathway for water in the upper layers of this soil type it was also found that peat depth and surface vegetation cover were associated with macroporosity and saturated hydraulic conductivity the proportion of macropore flow was found to be greater at 5 cm depth than at 0 10 and 20 cm depth peat beneath a sphagnum cover tends to be more permeable and a greater proportion of macropore flow can occur beneath this vegetation type functional macroporosity and matrix flow in the near surface layers of bare peat appear to have been affected by weathering processes comparision of results with rainfall records demonstrates that infiltration excess overland flow is unlikely to be a common runoff generating mechanism on blanket peat rather a saturation excess mechanism combined with percolation excess above much less permeable layers dominates the runoff response copyright 2001 john wiley sons ltd

coherence of seismic body waves from local events as measured by a small aperture array eight local earthquakes were recorded during the operation of a small aperture seismic array at pinyon flat california the site was chosen for its homogeneous granitic geology and its planar topography amplitude spectral ratios for the same signal measured at different stations had average values of less than 2 and maximum values of 7 magnitude squared coherences were estimated for all station pairs these estimates were highest for the p wave arrivals on the vertical component and lowest for the p wave recorded on the transverse component at 500 m station separation the p and s waves were incoherent above 15 hz and 10 hz respectively coherence for both the p and s waves decrease as frequency increases and as distance increases the coherence of signals from borehole sensors located at 300 and 150 m depth displays higher average coherence than equally spaced sites located on the surface the results here suggest that even for sites that appear to be very similar that is those which are located on a planar surface within a few meters of granite bedrock the measured seismic wavefield can be distorted substantially over scale lengths of 500 m coherence properties were calculated from synthetic seismograms which were computed for velocity models with exponential and self similar distribution perturbations standard deviations of 10 are not sufficient for the random velocity distributions to approximate the results from the small aperture array

the iron content of some red mediterranean soils from northeast spain and its pedogenic significance abstract alfisols cover 18 of the surface of the ne edge of the garraf massif se of barcelona catalonia most of these are mediterranean red soils some representative pedons especially over mesozoic limestones are discussed in this paper climate of the zone is littoral mediterranean mean temperature 16 c precipitation 650 mm pedoclimatic regimes are xeric and thermic vegetation is quercetum ilicis galloprovinciale horizon b is 5yr and 2 5yr in munsell hue with a phw of 7 2 to 8 6 all of them are base saturated and the majority recarbonated organic matter content is 2 5 some have an isohumic character the illuviation clay index ranges from 0 37 to 0 87 and the mean value of the illuviation fe index is 0 76 the nearly constant fed clay ratio indicates co illuviation values for fed are between 0 40 and 2 81 the mean feo is 0 057 and it ranges between 0 to 0 14 generally redness rating rr increases with fed values of fed fe1 vary from 0 22 to 0 82 and the mean is 0 54 rubefaction according to redness rating is moderate taxonomically calcic haploxeralfs predominate and are located at 50 70 m above sea level calcic palexeralfs at 70 80 m and again at 150 m and petrocalcic palexeralfs at 80 130 m are also found typic haploxeralfs are frequent over limestones at higher altitudes 260 m or overlying silicic rocks found at 35 65 m according to the 1967 french classification system they are red fersialitic and brown fersialitic soils and some are integrades with cinnamotnic soils marron encroute

slope scale variation of flow patterns in soil profiles tracer patterns in soil profiles observed in ten transport experiments using a dye and bromide are analysed to investigate the spatial distribution of the susceptibility for preferential flow on the slope scale flow patterns are characterised by interval scaled parameters that describe the plot scale variation of the vertical transport this measure is used for a cluster analysis to discriminate similar flow patterns a discriminant analysis of the obtained clusters shows whether the membership of a flow pattern to a cluster may be explained by independent quantities that characterise the conditions of the corresponding transport experiment and relative position of the field site on the slope the results suggest that sites located at the bottom of the slopes especially sites that are located near the brook have a higher susceptibility for preferential flow than those in the upper parts of a hill this is a characteristics of soil formation of hill slope soil catenas which usually leads to deeper biologically more active and often finer textured soils in the hill foot sector this in turn strongly affects the transport regime of these soils

factors controlling the distribution of piping in britain a reconnaissance abstract the distribution of piping in britain has been studied from a survey of 74 piped basins and a number of in depth studies at the individual basin scale the survey suggests that nearly 30 of britain is susceptible to piping erosion this is the area covered by soils with histic and vertic properties or with impermeable subsoil horizons lying in upland regions with high annual water balance and steep slopes at an intrabasin scale the intensity of piping shows a broad correspondence with the a s drainage index although there is no fixed relationship and some significant deviations are found inhomogeneities in soil properties and differential exposure to cracking may be the main cause landuse and vegetation cover may also affect distributions however the clearest intrabasin links between pipe distribution and vegetation patterns are found in upland moorland where the pipes are the cause rather than the product of patterns in both soils and vegetation

topographic controls upon soil macropore flow macropores are important components of soil hydrology the spatial distribution of macropore flow as a proportion of saturated hydraulic conductivity was tested on six humid temperate slopes using transects of tension infiltrometer measurements automated water table and overland flow monitoring allowed the timing of and differentiation between saturation excess overland flow and infiltration excess overland flow occurrence on the slopes to be determined and related to tension infiltrometer measurements two slopes were covered with blanket peat two with stagnohumic gleys and two with brown earth soils none of the slopes had been disturbed by agricultural activity within the last 20 years this controlled the potential for tillage impacts on macropores the proportion of near surface macropore flow to saturated hydraulic conductivity was found to vary according to slope position the spatial patterns were not the same for all hillslopes on the four non peat slopes there was a relationship between locations of overland flow occurrence and reduced macroporosity this relationship did not exist for the peat slopes investigated because they experienced overland flow across their whole slope surfaces nevertheless they still had a distinctive spatial pattern of macropore flow according to slope position for the other soils tested parts of slopes that were susceptible to saturation excess overland flow e g hilltoes or flat hilltops tended to have least macropore flow to a lesser extent for the parts of slopes susceptible to infiltration excess overland flow the proportion of macropore flow as a component of infiltration was also smaller compared with the rest of the slope the roles of macropore creation and macropore infilling by sheet wash are discussed and it is noted that the combination of these may result in distinctive topographically controlled spatial patterns of macropore flow copyright 2008 john wiley sons ltd

controls of soil pipe frequency in upland blanket peat 1 soil pipes were surveyed in 160 british blanket peat catchments using consistent application of ground penetrating radar soil pipes were found in all catchments the mean frequency of piping was 69 per kilometer of surveyed transect land management moorland gripping appears to exert the most important control on hillslope pipe frequency in blanket peats management practice in peatlands may therefore induce more rapid subsurface erosion carbon loss and landform denudation via enhanced preferential flow topographic position is also important with topslopes having greater pipe frequencies than footslopes followed by midslopes with lowest frequencies slope gradient however is not a significant factor in controlling blanket peat pipe frequency i propose that peat structural properties inherited from the way a blanket peat develops on a hillslope strongly control pipe network development this is manifested in the way slope position appears to control pipe frequency aspect appears not to influence pipe frequency in blanket peats except that it does play a weak role in catchments with annual precipitation 1500 mm here southwesterly facing slopes tend to have more frequent piping

terra rossa catenas in wisconsin usa abstract the soils in the unglaciated part of wisconsin have a loess cover over sedimentary rock mostly dolostone of ordovician age the dolostone has weathered and produced layers of red clay or terra rossa we have sampled 144 pedons of 16 catenas with different slope aspects and curvatures in a 70 km 2 area half of all the pedons had a red clay subsoil mostly 5yr 3 4 and had on average over 40 clay the mean thickness of the loess above the red clay was 50 cm but it ranged from 7 to 130 cm the thickness of the red clay ranged from 4 cm to 60 cm with an average thickness of 25 cm the red clay was found in every part of the landscape except the valley bottoms it was present in soils on summits shoulders backslopes and footslopes the red clay is only found over dolostone but not present on all dolostone ridges it was concluded that there is large variation in the terra rossa soilscapes of wisconsin and this variation can only partly be explained by topography

geochemical evidence of saharan dust parent material for soils developed on quaternary limestones of caribbean and western atlantic islands abstract most previous workers have regarded the insoluble residues of high purity quaternary limestones coral reefs and oolites as the most important parent material for well developed clay rich soils on caribbean and western atlantic islands but this genetic mechanism requires unreasonable amounts of limestone solution in quaternary time other possible parent materials from external sources are volcanic ash from the lesser antilles island arc and saharan dust carried across the atlantic ocean on the northeast trade winds soils on quaternary coral terraces and carbonate eolianites on barbados jamaica the florida keys united states and new providence island bahamas were studied to determine which if either external source was important caribbean volcanic ashes and saharan dust can be clearly distinguished using ratios of relatively immobile elements al 2 o 3 tio 2 ti y ti zr and ti th comparison of these ratios in 25 soils where estimated ages range from 125 000 to about 870 000 yr shows that saharan dust is the most important parent material for soils on all islands these results indicate that the northeast trade winds have been an important component of the regional climatology for much of the quaterary saharan dust may also be an important parent material for caribbean island bauxites of much greater age

quantitative study of piping processes in badland areas of the ebro basin ne spain abstract in the ebro basin piping is an ubiquitous erosion process in badland areas occurring in two main situations on slopes of exposed tertiary clays and in recently incised silty clay holocene valley fill sediments the quantitative importance of the main factors controlling piping processes in those conditions was obtained by statistical analysis based on multiple and stepwise regressions piping erosion is strongly related to a high sodium absorption ratio sar which favours clay dispersion however the statistical analysis indicates that the chemical characteristics and the physical chemical behaviour are a necessary condition but are not sufficient on their own to develop piping processes on the slopes piping is controlled by the physical and chemical properties of the material such as the dispersion index the granulometric fraction smaller than 4 m ph and crack density in the valley fill sediments piping is mainly controlled by the sulphate concentration in the water extract from saturated paste which is also associated with high sar values and the dispersion index in both geomorphic situations piping is always related to high crack density and high topographic gradient

iron oxide mineralogy of terra rossa and its genetic implications abstract fe d fe d fe t hematite geothite ratios and al substitution in hematite and goethite were found to vary to a rather limited extent in 48 terra rossa samples from various locations around the world this seems to indicate a rather specific pedoenvironment in which terra rossa is formed it is suggested that this pedoenvironment is characterized by an association of mediterranean climate high internal drainage due to the karstic nature of a hard limestone and neutral ph conditions under those conditions relatively high amounts of fe are released fe d fe t ca 0 7 from autochthonous and or allochthonous primary fe sources followed by preferential formation of hematite over goethite both having a medium level of al substitution the close association between terra rossa and the underlying limestone must therefore be seen in the role the rock plays for the water and air regimes of the soil rather than in its material characteristics except for soil ph neither an fe content in the limestone insufficient to explain the fe content of the solum nor the addition of eolian or alluvial material can therefore be used as an argument against a genetic relationship between terra rossa and its underlying limestone

hydraulic conductivity in upland blanket peat measurement and variability a key parameter used in wetland hydrological and landform development models is hydraulic conductivity head recovery tests are often used to measure hydraulic conductivity but the calculation techniques are usually confined to rigid soil theory this is despite reports demonstrating the misapplication of rigid soil theory to non rigid soils such as peats while values of hydraulic conductivity calculated using compressible techniques have been presented for fenland peats these data have never to the authors knowledge been compared to such calculations in other peat types head recovery tests slug withdrawal were performed on piezometers at depths ranging from 10 cm to 80 cm from the surface on north pennine blanket peats results were obtained using both rigid and compressible soil theories allowing comparison of the two techniques compressible soil theory gives values for hydraulic conductivity that are typically a factor of five times less than rigid soil calculations hydraulic conductivity is often assumed to decrease with depth in upland peats but at the study site in the northern pennines it was not found to vary significantly with depth within the range of peat depths sampled the variance within depth categories was not significantly different to the variance between depth categories showing that individual peat layers did not have characteristic hydraulic conductivity values thus large lateral and vertical differences in hydraulic conductivity over short distances creates problems for modelling but may help account for the high frequency of preferential flow pathways within what is otherwise a low matrix hydraulic conductivity peat hydraulic conductivity was found to vary significantly between sampling sites demonstrating that hillslope or catchment scale variability may be more important than plot scale variability values for compressibility of the peats are also reported these generally decline with depth and also vary significantly between sampling sites there are implications for the way in which measurements of hydraulic conductivity and other properties of blanket peat are interpreted as the effects of environmental change in one part of a peat catchment may be very different to those in another

fire decreases near surface hydraulic conductivity and macropore flow in blanket peat many peatlands have been subjected to wildfire or prescribed burning but it is not known how these fires influence near surface hydrological processes macropores are important flowpaths in the upper layers of blanket peat and were investigated through the use of tension disc infiltrometers which also provide data on saturated hydraulic conductivity measurements were performed on unburnt peat u where prescribed burning had taken place 2years b2 4years b4 and 15 b15 years prior to sampling and where a wildfire w had taken place 4months prior to sampling where there had been recent burning b2 b4 and w saturated hydraulic conductivity was approximately three times lower than where there was no burning u or where burning was last conducted 15years ago b15 similarly the contribution of macropore flow to overall infiltration was significantly lower between 12 and 25 less in the recently burnt treatments compared to b15 and u there were no significant differences in saturated hydraulic conductivity or macropore flow between peat that had been subject to recent wildfire w and those that had undergone recent prescribed burning b2 and b4 the results suggest that fire influences the near surface hydrological functioning of peatlands but that recovery in terms of saturated hydraulic conductivity and macropore flow may be possible within two decades if there are no further fires

evolution of soils on quaternary reef terraces of barbados west indies soils on uplifted quaternary reef terraces of barbados 125 000 to 700 000 yr old form a climo chronosequence and show changes in physical chemical and mineralogical properties with terrace age parent materials are dust derived from the sahara volcanic ash from the lesser antilles island arc and detrital carbonate from the underlying reef limestone although some terrace soils are probably eroded soils or their remnants are redder and more clay rich with increasing terrace age profile average al2o3 and fe2o3 content increases with terrace age which partially reflects the increasing clay content but dithionite extractable fe also increases with terrace age profile average k2o tio2 na2o tio2 and p2o5 tio2 values decrease with terrace age reflecting the depletion of primary minerals average sio2 al2o3 values also decrease with terrace age and reflect not only loss of primary minerals but also evolution of secondary clay minerals although they are not present in any of the parent materials the youngest terrace soils are dominated by smectite and interstratified kaolinite smectite which gradually alter to relatively pure kaolinite over 700 000 yr comparisons with other tropical islands where precipitation is higher and rates of dust fall may be lower show that barbados soils are less weathered than soils of comparable age it is concluded that many soil properties in tropical regions can be potentially useful relative age indicators in quaternary stratigraphic studies even when soils are eroded or changes in soil morphology are not dramatic

mineralogical and geochemical indicators of the polygenetic nature of terra rossa in istria croatia abstract terra rossa in istria is situated on the jurassic cretaceous paleogene carbonate plain and is considered a polygenetic reddish soil which bears typical terra rossa fe oxide characteristics e g fe d and fe d fe t the difference in particle size mineralogy and geochemistry observed between terra rossa and the insoluble residue of limestones and dolomites clearly indicates that the additions of external materials might have diminished the influence of insoluble residue of limestones and dolomites as the primary parent material of terra rossa in istria terra rossa is clay and silty clay composed of quartz plagioclase k feldspar micaceous clay minerals illitic material and mica kaolinites kl d and kl chlorite vermiculite low charge vermiculite or high charge smectite mixed layer clay minerals other than illitic material hematite goethite and xrd amorphous inorganic compound calcite dolomite and boehmite are sporadically present and are of local importance kaolinites and illitic material are dominant clay mineral phases in the clay fraction of all terra rossa from istria kaolinite which does not form intercalation compounds with dimethylsulfoxide dmso is the dominant mineral phase in fine clay and is considered predominantly authigenic rather then inherited from parent materials neither the content and particle size distribution nor the bulk and clay mineralogy of the insoluble residue of limestone and dolomite support development of terra rossa entirely by dissolution of carbonate rock if terra rossa has developed only from the insoluble residue of limestone and dolomite its clay content due to weathering should be higher than that in the insoluble residues which is not the case plagioclase was found only in one insoluble residue while all terra rossa samples contain this mineral moreover insoluble residues do not contain vermiculite which was observed in small amounts in clay fraction of all terra rossa samples na 2 o k 2 o 100 zr nb and zr ti 1000 ratios in the majority of terra rossa samples are much higher than in the insoluble residue of limestones and dolomites which also supports external material influence in the genesis of terra rossa materials other than the insoluble residue of limestones and dolomites which might have contributed to terra rossa are loess sediments whose deposition was very important recurrent process in istria probably since the early middle pleistocene and flysch sediments which extended much more southwards from its present position analyses performed indicate that both loess older than that of the upper pleistocene age and flysch might have contributed in the genesis of terra rossa

hydrological hotspots in blanket peatlands spatial variation in peat permeability around a natural soil pipe 1 measurements were made of the hydraulic conductivity k of peat around a natural soil pipe in a blanket bog this is the first investigation of decimeter scale variability in both vertical k and horizontal k in blanket peats which were found to be higher than indicated by previous research this information suggests that it may be appropriate to reconsider i the spatial sampling strategies employed to investigate subsurface flow in blanket peatlands and ii how field data are used to parameterize flow models critically there was spatial structure in the heterogeneity with a wedge of high k peat directly above the pipe forming a hydrological conduit between near surface peat and the perennially flowing pipe there was also significantly greater horizontal k parallel to the pipe s orientation compared with horizontal k perpendicular to the pipe determinations of the triaxial anisotropy of k undertaken for the first time in peat soils revealed substantial directional variations in k the k around the pipe peat interface was investigated however sample length dependency of k for peat samples precluded the investigation of a hypothesized low k skin around the pipe

terra rossa genesis implications for karst and eolian dust a geodynamic thread abstract although terra rossa has long been thought to form by residual dissolution of limestone and or by accumulation of detrital mud ash or dust on preexisting karst limestones we present conclusive new field and petrographic evidence that terra rossa forms by replacement of limestone by authigenic clay at a moving metasomatic front several centimeters wide the red clay s major chemical elements al fe and si probably come from dissolved eolian dust the replacement of calcite by clay exhibits a serrated microstylolitic texture that helps prove that replacement happens not by dissolution precipitation as conventional wisdom has it but by pressure solution of calcite driven by the crystallization stress generated by the growth of clay crystals the acid produced by the isovolumetric replacement of limestone by clay quickly dissolves out additional porosity permeability in an adjacent slice of limestone within the front triggering a reactive infiltration instability that should theoretically

pedogenesis of red soils overlaid coral reef terraces in the southern taiwan abstract red soils developed above the reef limestones are commonly observed in the world their characteristic properties of high contents in clays and iron oxides reddish hue are usually classified themselves as inceptisols alfisols ultisols or mollisols in soil taxonomy the genetic contexts between the soils and beneath limestone have been revealed for gauging paleo landform surface processes relating to paleoclimatic shifts since the late pleistocene there are levels of reef marine terraces in altitude in the hengchun peninsula of taiwan their surfaces are covered by thick reddish soil enriched with iron oxides however these terra rossa like soils distributed on the reef limestone are actually developed from heterogeneous detrital materials instead of developing from the insoluble residue of the limestone according to the soil taxonomy the soils on the higher terraces are classified as the typic paleudults or typic kandiultults they are equivalent to the alisols in wrb system the soils on the lower terraces are classified as typic udipsamments and lithic eutrudepts and they are equivalent to the arenosols and cambisols respectively this study suggests that the terra rossa like soils in the study are developed from the parent materials of fluvial deposits which are subject to the landform surface processes during the interglacial

shallow elasticity structure from colocated pressure and seismic stations in the pinon flat observatory and estimation of vs30 author s tanimoto toshiro wang jiong abstract summary an algorithm developed in tanimoto a wang for deriving shallow elasticity structure from colocated pressure and seismic instruments is applied to data at nine stations in the pinon flat observatory pfo in southern california depth resolution kernels indicate that this approach can recover near surface shear modulus structure in the upper 50 100 m of the earth our estimate for vs30 at the closest station bph01 agrees with an independent result by yong et al which was based on an active source survey with a geophone array vs30 derived from the borehole s wave speed model by fletcher et al also agrees with estimates at nearby locations considering the size of uncertainties derived structures are much smoother than their models however this is because our method analyses slow quasi static deformation of the solid earth in the frequency range 0 005 0 05 hz that inherently limits depth resolution lack of detailed variations in structures does not seem to be the problem for estimating vs30 as vs30 is an averaged quantity from the upper 30 m of the earth also our estimates are not affected by different choices of frequency range in the inversion however our method may have some difficulty at stiff hard rock sites because ground deformation caused by surface pressure can become small and the key observables in our method the ratios between seismic amplitude and surface pressure change become difficult to measure accurately

sediment budget for an eroding peat moorland catchment in northern england this paper describes a detailed contemporary sediment budget from a small peat covered upland catchment in upper teesdale northern england the sediment budget was constructed by measuring 1 sediment transfers on slopes 2 sediment flux on the floodplain and through the main stream channel and 3 sediment yield at the catchment outlet measurements were taken over a four year monitoring period between july 1997 and october 2001 when interannual variations in runoff were relatively small three sites were selected to represent the major erosion subsystems within the catchment an area of bare peat flats a pair of peat gullies and a 300 m channel reach collectively the sites allow detailed characterization of the main patterns of sediment flux within the catchment and can be scaled up to provide an estimate of the sediment budget for the catchment as a whole this constitutes the first attempt to provide a complete description of the functioning of the sediment system in eroding blanket peatlands results demonstrate that fluvial suspended sediment flux is controlled to a large degree by channel processes gully erosion rates are high but coupling between the slopes and channels is poor and therefore the role of hillslope sediment supply to catchment output is reduced consequently contemporary sediment export from the catchment is controlled primarily by in channel processes error analysis of the sediment budgets is used to discuss the limitations of this approach for assessing upland sediment dynamics a 60 per cent reduction in fluvial suspended sediment yield from rough sike over the last 40 years correlates with photographic evidence of significant re vegetation of gullies over a similar period this strongly suggests that the reduced sediment yields are a function of increased sediment storage at the slope channel interface associated with re vegetation copyright 2005 john wiley sons ltd

a preliminary investigation into the relationship between long period seismic noise and local fluctuations in the atmospheric pressure field summary the displacement response of an elastic half space to a plane pressure wave is examined in order to establish the conditions under which sources of this type can contribute significantly to the long period seismic noise field the study is restricted to pressure waves which propagate at velocities well below the seismic wave velocities characteristic of the half space the numerical studies indicate that pressure waves with amplitudes of 100 pbar or more can contribute significantly to the long period vertical background noise observed at the surface provided that the detectors are located on sections of alluvial fill or poorly to moderately indurated sandstones and shales whose thicknesses are greater than about a kilometre these same waves can also create significant tilt noise on long period horizontal seismographs located at or near the surface regardless of the rock type the seismic disturbances created by pressure waves decay rapidly away from the surface therefore it appears that it may be possible to eliminate the effects of atmospherically generated noise by placing the detectors at moderate depths

preferential flow paths in a water repellent clay soil with grass cover grass covered heavy basin clay soils in the netherlands appeared to be water repellent water repellency in the top layers of these soils occurred mainly as a coating on the aggregates the variation in soil moisture content over short distances was studied by sampling the soil 10 times during the period august 31 1993 to december 22 1994 each time 35 samples 100 cm3 were taken in close order over a distance of 195 cm at depths of 0 5 10 15 20 25 and 30 35 cm differences between minimum and maximum soil moisture contents were high in all layers sampled occasionally as much as 28 vol when the clay soil is dry a major proportion of the water from precipitation or sprinkler irrigation may flow rapidly through shrinkage cracks to the subsoil bypassing the matrix of the clay peds however preferential flow is not limited to macropore flow irregular wetting patterns are also formed through the small pores of the matrix the relationship between dry bulk density and volumetric water content was found to be positive when the clay soil was relatively dry and negative when it was relatively wet

application of ground penetrating radar to the identification of subsurface piping in blanket peat natural soil pipes are common and significant in upland blanket peat catchments yet there are major problems in finding and defining the subsurface pipe networks this is particularly important because pipeflow can contribute a large proportion of runoff to the river systems in these upland environments and may significantly influence catchment sediment and solute yields traditional methods such as digging soil pits are destructive and time consuming particularly in deep peat and only provide single point sources of information this paper presents results from an experiment to assess the use of ground penetrating radar gpr to remotely sense pipes in blanket peat the technique is shown to be successful in identifying most of the pipes tested in the pilot catchment comparison of data on pipes identified by gpr and verified by manual measurement suggests that pipes can be located in the soil profile with a depth accuracy of 20 to 30 cm gpr identified pipes were found throughout the soil profile however those within 10 20 cm of the surface could not be identified using the 100 or 200 mhz antennae due to multiple surface reflections generally pipes smaller than 10 cm in diameter could not be identified using the technique although modifications are suggested that will allow enhanced resolution future work would benefit from the development of dual frequency antennae that will allow the combination of high resolution data with the depth of penetration required in a wetland environment the gpr experiment shows that pipe network densities were much greater than could be detected from surface observation alone thus gpr provides a non destructive fast technique which can produce continuous profiles of peat depth and indicate pipe locations across survey transects copyright 2002 john wiley sons ltd

uplift rate of coral reef terraces in the area of kupang west timor preliminary results abstract a th u date of 152 000 years obtained from the prominent fifth step at 44 m elevation of a flight of 7 well defined raised reef terraces at cape namosain 5 km west of kupang allows inference of a preliminary mean uplift rate of 0 3 mm yr since the last interglacial such a slow uplift rate is supported by the observation of numerous large modern reef platforms and of very limited mid holocene emergence if any throughout the region subject to conformation through further dating this suggests the existence of a more rapid uplift zone in central west timor by contrast with the area of kupang to the west and of northern east timor and atauro island to the east possibly in relation with the nw se seismic tear zone which has been recently pointed out within the subducting plate north of west timor one of the main interests in the terraces of cape namosain apart from its neotectonic aspect resides in the fact that there may be an oppurtunity to define the 180 000 year old paleo sea level terrace viii of huon peninsula based on the geomorphological interpretation of the series it could correspond here to the fourth or the sixth terrace field investigation and dating in that regard are currently in progress another th u date of 124 000 years obtained on the lowest emerged terrace 7 m above low tide in the southeast of the nearby island of semau indicates that this second area has been uplifting little during the last 125 000 years this together with the observation of tilts and other structural features leads to the conclusion that the area of the southwest of kupang is affected by differential uplifts and block faulting

water movement and isoproturon behaviour in a drained heavy clay soil 1 preferential flow processes abstract the processes and mechanisms that control pesticide transport from drained heavy clay catchments are being studied at wytham farm oxford university in southern england in the first field season field drain water contained high concentrations of pesticide soil studies demonstrated that the main mechanism for pesticide translocation was by preferential flow processes both over the soil surface and through the soil profile via a macropore system that effectively by passed the soil matrix this macropore system included worm holes shrinkage cracks and cracks resulting from ploughing rainfall events in early winter rapidly created a layer of saturation in the a horizon perched above a b horizon of very low hydraulic conductivity drain flow was initiated when the saturated layer in the a horizon extended into the upper 0 06m of the soil profile thereafter water moved down slope via horizontal macropores possibly through a band of incorporated straw residues these horizontal pathways for water movement connected with the fracture system of the mole drains thus feeding the drains overland flow occurred infrequently during the season

genesis and mineralogy of soils formed on uplifted coral reef in west timor indonesia many scientists believe that soils forming on or in association with limestone are derived from consolidated limestone rocks or the limestone residuum the objective of this study was to determine the genesis of reddish alfisols and black mollisols formed on uplifted coral reefs in west timor indonesia a total of 24 alfisols and 23 mollisols were studied and sampled rock samples were also collected from the surface from within the profile and from the bedrock of representative profiles dissolution of the coral limestones yielded 1 7 insoluble residue oxides of si k ca and mg were present at higher concentrations in the insoluble rock residues than in the bulk soils and clay fractions concentrations of al and fe oxides were higher in the soils than in the residues considering these possibility exists that exogenic materials atmospheric dusts or volcanic ash may have also contributed to the formation of these soils studied alfisols were dominated by kaolinite followed in a decreasing order by vermiculite gibbsite and quartz whereas mollisols were predominantly smectite and mica followed by kaolinite and quartz the mineralogy of the insoluble residues was similar to that of the clay of mollisols the presence of kaolinite in residues and in the clay of both soils suggests that kaolinite may have been derived from the residue therefore we concluded that weathering of the underlying limestone is the main source contributed to the development of both the alfisols and the mollisols based on the principles of mineral transformation in the soil particularly higher kaolinite content we conclude that alfisols occurring in more stable surfaces and are strongly weathered than mollisols