integrated interpretation of 3d seismic data to enhance the detection of the gold bearing reef mponeng gold mine witwatersrand basin south africa we present an integrated approach to the seismic interpretation of one of the world s deepest gold ore body carbon leader reef using three dimensional seismic data ultrasonic velocity measurements at elevated stresses and modified instantaneous attribute analysis seismic wave velocities of the drill core samples quartzite shale and conglomeratic reef from the mine are sensitive to uniaxial stress changes i e they slowly increase with increasing pressure until they reach maximum value at 25 mpa for all the samples seismic velocities are constant above 25 mpa indicating a possible closure of microcracks at stress corresponding to 1 0 km 1 5 km a reflection coefficient of 0 02 computed between hanging wall and footwall quartzites of the carbon leader reef ore body suggests that it may be difficult to obtain a strong seismic reflection at their interface our modified seismic attribute algorithm on the other hand shows that the detection of the lateral continuity of the carbon leader reef reflector can significantly be improved by sharpening the seismic traces three dimensional seismic data reveal that faults with throws greater than 25 m that offset the carbon leader reef can clearly be seen faults with throws less than 25 m but greater than 2 m throw were identified through horizon based attribute analysis while most dykes and sills with thickness less than 25 m were invisible the detection of the lateral continuity of the carbon leader reef reflector and its depth position is greatly improved by integrating the modified instantaneous attributes with controls from borehole observations the three dimensional visualization and effective interpretation of the carbon leader reef horizon shows a host of structurally complex ore body blocks that may impact future shaft positioning and reduce its associated risks

inertia gravity waves associated with deep convection observed during the summers of 2005 and 2007 in korea 1 characteristics of inertia gravity waves associated with convection are investigated in the lower stratosphere using high resolution radiosonde data observed from 18 june to 15 july of 2005 and 2007 in korea three dimensional ray tracing model and reanalysis data are used to investigate the propagation and the sources of the observed waves the observed waves associated with convections are discriminated based on the existence of convections when and where the rays reach the average height range of convective clouds waves observed in 2005 and 2007 show similar spectral characteristics but wave energy in 2007 is significantly larger than in 2005 the observed waves propagate from three source regions the northeastern southeastern and western regions around korea they show preferential propagation directions based on their sources and convections from the western region generate larger amplitude gravity waves than the other two regions the spectral characteristics of the observed waves are determined largely by those of the convective forcing along with the wave propagation condition associated with background wind and stability the significantly larger mean wave energy in 2007 occurs because more observed waves originate from the western region of korea in 2007 than in 2005 where convective forcing is much larger than in the other source regions

space time description of nonstationary trapped lee waves using st radars aircraft and constant volume balloons during the pyrex experiment abstract the third intensive observation period iop3 of pyrex was a case of strong lee waves generated by a southerly wind crossing the pyrenees chain upstream radiosounds and measurements obtained by aircraft along the chain transect and by constant volume balloons launched near the crest provided spatial characteristics of the lee wave at different times and heights values ranging from 7 to 14 km for the horizontal wavelength and from 3 to 5 m s 1 for the maximum amplitude of the air vertical velocity were observed the lee wave horizontal extent measured from the crest line reached 30 to 55 km in addition two very high frequency stratosphere troposphere vhf st radars one on the mountain mean axis and another downstream in the lee wave field observed the temporal variations of the vertical profiles of the vertical velocity the analysis of those observed variations and their vertical distribution allowed the stationarity of the wave to be studied the lee wave was found to be far from stat

stability analysis of slurry trenches in similar layered soils slurry trenches are often used to impede groundwater flow or to contain soil and groundwater contamination the stability of the slurry trench during excavation and prior to backfilling is a major concern in design a horizontal slice method for stability analysis of slurry trenches which allows consideration of soil stratification is presented vertical force equilibrium for each slice of the sliding mass and horizontal force equilibrium for the whole sliding mass are considered on the basis of limit equilibrium the factor of safety is obtained via the newton raphson method and the critical slip surface corresponding to the minimum factor of safety is located by the pattern search method the proposed method is verified via consideration of a previously reported problem it is then applied to a full scale field experiment in three layer soils the obtained minimum factor of safety and location of the slip surface of the sliding mass are in excellent agreement with the experimental measurements analyses of trenches having a weak layer at various depths demonstrate potential variations in slip surface inclination between soil layers

seismic and geoelectric evidence for collisional and extensional events in the fennoscandian shield implications for precambrian crustal evolution extensive deep seismic and electromagnetic sounding programs have resulted in tens of deep refraction seismic profiles normal incidence reflection profiles several hundred magnetotelluric soundings and several magnetovariational array observations results are compiled into four maps 1 moho depth 2 thickness of the lower crustal high velocity layer vp 7 km s 3 depth to the upper interface of the high velocity layer and 4 distribution of upper and middle crustal electrical conductors the moho depth is approximately 40 km in the archaean domain and varies between 40 and 65 km in the svecofennian domain most of the thickness variation 0 24 km is concentrated in the lower crustal high velocity layer electrically the crust is formed of several rather homogeneous either resistive or conductive blocks that are bounded by upper and middle crustal conductive zones the cratonized archaean crust experienced an extensional phase during which a thin mafic lower crustal high velocity layer was produced in association with mafic dykes 2 2 2 1 ga and well conducting volcanogenic and metasedimentary belts 2 5 2 0 ga the moho of the archaean domain was consequently reformed in the early proterozoic major thickening of the crust 50 65 km occurred when a svecofennian island arc and the archaean craton collided the svecofennian orogeny 1 76 1 9 ga resulted in a collage of metasedimentary rocks squeezed between crustal blocks of the island arc the internal terrane boundaries are seen as good reflectors and or inclined or vertical conductors that extend at least to the middle crust the thick high velocity 7 km s lower crust is a combination of mafic lower crust of the island arc crustal blocks and mafic additions from either delamination of the lithosphere after the collision or from a period of late svecofennian subduction the collisional boundary is also preserved as a discontinuous conductive zone between the archaean and svecofennian domains the thickened crust was subsequently thinned to 42 km along e w striking zones during an extensional period characterized by the intrusion of anorogenic rapakivi granitoid batholiths coeval mafic dykes and gabbro anorthosite bodies 1 6 1 5 ga the crust of the central part of the shield has since remained virtually intact

diurnal variation in vertical motion over the central equatorial pacific from vhf wind profiling doppler radar observations at christmas island 2 n 157 w wind profiling doppler radars measure vertical motions along a vertically directed beam by averaging over long periods it is possible to measure very small mean vertical motions long term measurements at christmas island have been analyzed to determine the diurnal variation in the vertical motion field the outstanding feature that emerges from the analysis is a pronounced diurnal cycle in the subsiding motion of the main troposphere 4 10 km and an equally pronounced diurnal cycle in upward motion centered around the altitude of the tropopause the possibility of radiative forcing of the observed diurnal cycle is considered in the context of the diurnal variation of atmospheric diabatic heating and cooling rates

aircraft measurements of mountain waves and their associated momentum flux over the british isles the hercules and canberra aircraft of the meteorological research flight have made a number of flights to investigate mountain waves over different mountainous areas of the british isles results from five flight days are presented in this study for each flight day the observed values of the dominant wavelength and the wave amplitude as a function of height were compared with the values predicted by two dimensional linear lee wave theory good agreement was obtained in four of the five cases measurements of the vertical flux of horizontal momentum show that the largest values were obtained when the wavelength was 20 9 km and the waves were only weakly trapped on this occasion the flux was observed to be constant with height in the range over which measurements were made supporting a theoretical result of eliassen and palm the value 0 35nm 2 is comparable with some aircraft measurements made over the rocky mountains

vhf doppler radar observations of vertical velocities in the vicinity of the jet stream abstract the sousy sounding system vhf very high frequency radar in germany has been used to make observations of the upper troposphere and lower stratosphere for a number of cases during which the jet stream was overhead or nearly so the horizontal and vertical wind components have been calculated from oblique beam doppler radial velocities using a velocity azimuth display vad technique and averaged over periods ranging from 3 h to about 1 day the vertical wind is found to reverse direction near the height of the maximum horizontal wind in all cases observed in general agreement with a conceptual model and with other radar measurements most commonly downward vertical motion is observed below the jet stream wind maximum and upward motion above it for these cases but in one instance such a circulation has been found to undergo a reversal as the position of the jet shifted the vertical velocities have magnitudes in excess of 0 5 m s 1 no minimum critical horizontal wind speed sums to be requi

delamination of eclogitized lower crust control on the crust mantle boundary in the central fennoscandian shield abstract the crustal structure of the central part of the fennoscandian shield is dominated by a high velocity lower crust hvlc vp 7 3 7 5 km s at the depth of 40 63 km in an area of ca 400 km 600 km formed in the palaeoproterozoic svecofennian orogen at 1 91 1 87 ga in the area of the hvlc the moho is deeper than 50 km and attains depths of up to 63 km in eastern finland at the archaean proterozoic boundary zone we suggest that the present moho dates back to late svecofennian time and was determined by delamination of high density eclogitized lower crust after tectonic collisional thickening of crust densities deduced from seismic and gravity data suggest a very small or completely lacking density contrast between lower crust and uppermost mantle new geological evidence from kimberlite hosted garnet xenocrysts supports the presence of a garnet population with compositions in agreement with crustal eclogitic garnets in addition small clinopyroxene garnet mineral aggregates microxenoliths show omphacitic clinopyroxene compositions therefore the presence of eclogites in the high velocity lower crust is implied although the eclogite proportion as estimated from seismic velocity data is only a few percent in the present hvlc with results on near incidence and wide angle seismic studies and geological and geochemical data on heat producing elements we modeled the svecofennian collision and the thermal evolution of the crust to provide temperature constraints for the delamination model the constructed thermal model simulates the genesis of svecofennian synkinematic at 1 89 1 88 ga and postkinematic 1 88 1 87 ga granitoids as well as the general metamorphic grade of the surface rocks and lower crustal xenoliths moreover the narrow distribution of the ages of the svecofennian mafic ultramafic magmatism ca 1 89 1 87 ga dispersed around the hvlc area is explained by the homogeneous warming of the lithosphere the conditions of lower crustal delamination were estimated with a rayleigh taylor convective instability model constrained with lower crustal and upper mantle rheological data delamination of a lower crustal eclogite layer 5 30 km thick takes place in about 7 50 ma if the rock dynamic viscosity is 1 1021 pa s it requires temperatures of 1000 c in the lower crust and upper mantle in the svecofennian crust such temperatures were attained at about 1860 1850 ma i e after the orogenic peak we conclude that the moho of the hvlc area was controlled by delamination of a ca 5 10 km thick layer of high density lowermost crust into the mantle such a density controlled process may have controlled the moho depth also in other proterozoic shield areas

observed performance of three adjacent 48 m depth concrete diaphragm wall panels in silty soils the performance of three adjacent 48 m depth concrete diaphragm wall panels in silty soils is measured throughout the complete process of the wall installation including trench excavation trench c

a full scale stability experiment on a diaphragm wall trench this paper presents the results of a full scale field experiment on the stability of a slurry filled diaphragm wall trench the objective of this experiment was to observe the failure pattern of a

lidar observations of atmospheric dynamics in the troposphere and lower stratosphere over arecibo a periodic wave structure with a vertical wave length typically 2 km between 14 and 23 km altitudes has been identified in lidar measurements of relative density profiles at 589 nm that were made by the university of illinois group during the march april aida 1989 campaign effort the equivalent temperature fluctuations are several degrees in magnitude also seen are stratified aerosol layers at altitudes near 25 km with a vertical extent of 1 km both of these phenomena show a downward phase speed between 1 and 3 cm s 1 the lower periodic structure is believed to be the same phenomenon seen previously in 430 mhz measurements of winds obtained at arecibo observatory the source of this structure remains uncertain cornish and larsen 1989 and sato and woodman 1982a considered this structure to be a quasi inertial long period wave hines 1989 proposed instead the identification of this structure with a stationary wave system generated by orographic waves created through the interaction of the subtropical trade winds with the mountainous terrain of puerto rico the higher altitude feature seen in the aida lidar observations is believed to be an aerosol layer with a scattering ratio of about 1 15 an alternative explanation is clear air turbulence but the signature of the 10 k fluctuation deduced from the lidar observations was not found in the san juan balloon measurement of the temperature profile for the lower stratosphere

gravity waves generated by convection during twp ice i inertia gravity waves gravity waves are analyzed in radiosonde soundings taken during the tropical warm pool international cloud experiment twp ice campaign the properties of the inertia gravity waves are analyzed in part i whereas part ii focuses on high frequency gravity waves two groups of inertia gravity waves are detected group l long vertical wavelength in the middle stratosphere during the suppressed monsoon period and group s short vertical wavelength in the lower stratosphere during the monsoon break period waves belonging to group l propagate to the southeast with a mean intrinsic period of 35 h and have vertical and horizontal wavelengths of about 5 6 km and 3000 6000 km respectively ray tracing calculations indicate that these waves originate from a deep convective region near indonesia waves belonging to group s propagate to the south southeast with an intrinsic period vertical wavelength and horizontal wavelength of about 45 h 2 km and 2000 4000 km respectively these waves appear to originate from convection in the vicinity of new guinea

crustal structure and composition of the oslo graben norway abstract although more than 250 my old the oslo graben has retained a distinctive distribution of p wave velocities associated with rifting intrusion and underplating of the thinned crustal section we calculate poisson s ratio values from crustal p and s wave velocities along an 400 km long profile across the southern scandinavian peninsula with a focus on the oslo graben plutonic rocks are now exposed at the surface in the graben due to post rifting erosion and the corresponding low 5 5 km s p wave velocities extend to depths of 3 km the p wave velocity and poisson s ratio between depths of 6 and 34 km are 5 higher inside than outside the rift boundaries which together with thickening of the 7 km s lower crust beneath the rift indicate magmatic intrusions poisson s ratio of 0 27 and high 7 1 7 4 km s velocities indicate a heterogeneous composition lower crust the thickened high velocity lower crust is 1 5 times wider than the surface expression of the rift and extends to both the east and west of the main rift axis depth dependant extension may have occurred within the rift and may account for the significant volumes of volcanic output despite the small surface extension observed the added volume of intrusive material may explain why the moho up warp is small as little as 2 km at the rift based on the new p wave velocities poisson s ratio measurements and the thickness of the magmatic underplate apparent values for the rift are estimated to be 1 5 but when intrusion within the crust is included could be as high at 2 3

modelling the thermal evolution of a collisional precambrian orogen high heat production migmatitic granites of southern finland abstract we present results of thermal and geochemical modelling of paleoproterozoic southern finland which is characterized by formation of high heat production migmatitic granites post orogenic granitoids and high temperature low pressure metamorphism at 1 85 1 78 ga during late svecofennian time metamorphic grade is mostly amphibolite facies 4 5 kbar 650 700 c but also granulite facies 6 kbar up to 800 c occurs our results suggest that the thermal evolution of the area can be modelled as a process of rapid crustal thickening up to 70 km in a plate collision at ca 1870 1860 ma ago followed by conductive heating of the crust simultaneous exhumation and partial melting of middle crust and emplacement of the melts in the upper crust as late orogenic high heat production granites at about 1825 ma ago the upper crust collapsed gravitationally at about 1820 ma but the crust was still thick 57 km when the main orogenic era terminated about 1800 ma ago in modelling the thermal evolution we applied crustal heat production values constrained by geochemical data and a conservative estimate i e relatively low value for mantle heat flow density the modeled temperatures at 30 50 km depths in the thickened crustal stack exceed the dehydration melting temperatures of micas at 40 km 750 c for muscovite and 800 c for biotite respectively 25 35 ma after the collision and thickening of crust the results explain the high temperature low pressure metamorphism in southern finland as an inevitable consequence of crustal thicknening leading to an increase of the total heat production of the crust crustal thicknening is the main heat source for melting and metamorphism of the orogeny advective and latent heat brought by the melts further increased the temperatures at the emplacement depth and contributed to the granulite facies metamorphism that is spatially related to the migmatitic granites geochemical models suggest that the high concentrations of u and th in the migmatitic granites can be attributed to about 20 vol partial melting of deeply buried sediments and volcanic rocks about 36 71 of the original u 18 54 of th and 34 46 of k respectively in the source rock types entered the melt phase no anomalous concentrations of these elements in the source rock are required in addition to explaining the migmatitic late orogenic granite and post orogenic granitoid genesis the collision model implies that the middle lower crust and the upper mantle continued warming until the mesoproterozoic times which suggests a causal link between the svecofennian thermal evolution and the extensive bimodal rapakivi granite and anorthosite magmatism in the fennoscandian shield about 200 250 ma later

deep crustal mineral assemblages and potential for crustal rocks below the moho in the scottish caledonides summary the scottish caledonian lower crust is strongly seismically reflective beneath the moho at about 30km very few reflections are seen on seismic records with the exception of a strong reflector at about 50km depth the rocks between the moho and this strong reflector have been interpreted as crustal but with mantle velocities and densities we report tests of this in which the densities and seismic velocities of likely crustal precursors are assessed through determination of the stable mineral assemblages along geotherms appropriate to the region likely crustal precursors were selected from suites of exhumed deep crustal rocks and deep crustal xenoliths and from a variety of basaltic rocks mineral assemblages were estimated using a variant of the lowest free energy search procedure of wood 1987 with account taken of nonideal mixing in solid solutions geotherms were calculated from the heatdow heatproduction relationship for the scottish caledonides using the methods of pollack chapman 1977 seismic velocities were estimated from empirical density velocity relationships and from the velocities of individual mineral species weighted for modal proportions

seismic structure and composition of the crust beneath the southern scandes norway abstract new results on p and s wave seismic velocity structure in southern norway indicate that the crust has an average poisson s ratio of 0 25 is predominantly of felsic intermediate composition and lacks a significant mafic lower crust a crustal scale refraction seismic study magnus rex mantle investigations of norwegian uplift structure refraction experiment acquired data along three 300 to 400 km long active source seismic profiles across the southwest scandinavian domain in southern norway the youngest section of the fennoscandian shield moho depths in the domain are 36 40 km thinning towards the continental shelf and oslo graben the high vp lower crust beneath the southwest scandinavian domain vp 7 km s is around 4 km thick crustal structure in the adjacent svecofennian domain differs significantly moho depths reach 50 km and an up to 24 km thick high vp lower crust is present strong p and s wave arrivals are recorded from magnus rex from which poisson s ratio for the crust is calculated the unusually strong s wave arrivals allow rare insight into crustal poisson s ratio structure that is not commonly available from active source data the thinness of the mafic lower crust in southern norway is in significant contrast to other parts of the fennoscandian shield and delamination or convective removal of the lower crust is proposed tectonic events that may have triggered detachment of the lower crust include extensional collapse after the caledonian orogeny and permian extension

full scale crustal interpretation of kokkola kymi kokky seismic profile fennoscandian shield the kokkola kymi deep seismic sounding profile crosses the fennoscandian shield in northwest southeast nw se direction from bothnian belt to wiborg rapakivi batholith through central finland granitoid complex cfgc the 490 km refraction seismic line is perpendicular to the orogenic strike in central finland and entirely based on data from quarry blasts and road construction sites in years 2012 and 2013 the campaign resulted in 63 usable seismic record sections the average perpendicular distance between these and the profile was 14 km tomographic velocity models were computed with jive3d program the velocity fields of the tomographic models were used as starting points in the ray tracing modelling based on collected seismic sections a layer cake model was prepared with the ray tracing package seis83 along the profile upper crust has an average thickness of 22 km average and p wave velocities vp of 5 9 6 2 km s near the surface increasing downward to 6 25 6 40 km s the thickness of middle crust is 14 km below cfgc 20 km in se and 25 km in nw but vp ranges from 6 6 to 6 9 km s in all parts lower crust has vp values of 7 35 7 4 km s and lithospheric mantle 8 2 8 25 km s moho depth is 54 km in nw part 63 km in the middle and 43 km in sw yet a 55 km long section in the middle does not reveal an obvious moho reflection s wave velocities vary from 3 4 km s near the surface to 4 85 km s in upper mantle consistently with p wave velocity variations results confirm the previously assumed high velocity lower crust and depression of moho in central finland

inertio gravity wave parameter estimation from cross spectral analysis we outline a method for extracting inertio gravity wave parameters using the autospectra and cross spectra of the horizontal perturbation winds in essence we define a statistical hodograph for each spectral bin thus combining the advantages of the rotary spectrum and hodograph methods furthermore we include the effects of the background vertical shear in the parameter estimation equations a step that had often been omitted in the past applying this technique to a long period data set taken with the arecibo 430 mhz radar we explore its usefulness as well as its limitations our analysis of this data set also supports the interpretation of horizontal wind perturbation rotation in the lower stratosphere over arecibo as inertio gravity waves rather than mountain waves imbedded within a background vertical shear

the crustal structure along the polar profile from seismic refraction investigations abstract seismic refraction investigations along a 440 km long profije on the northern baltic shield have resolved the crustal structure in this area of archaean to early proterozoic lithosphere formation the profile called the polar profile extends approximately along a sw ne oriented line from the karelian province in northern finland across the lapland granulite belt and the kola peninsula province to the varanger peninsula in northeastern norway at six shotpoints large explosions 200 1680 kg and at three shotpoints small explosions 80 kg were detonated and recorded at an average station spacing of 2 km providing high quality record sections a two dimensional cross section of the crust was obtained by forward modelling using ray tracing techniques high velocity bodies are found in the upper crust related to the karasjok kittila greenstone belt and the lapland granulite belt they extend to a depth of 6 13 km in the karelian province in the southwest a low velocity zone was found between the depths of 8 and 14 km the middle crust shows a slight increase in the average velocities from the southwest to the northeast and a small velocity jump is found along a mid crustal boundary between 18 and 21 km the thickness of the middle crust varies between 16 and 18 km the lower crust and the crust mantle boundary moho show considerable lateral variation the top of the lower crust lies between 26 and 33 km while its thickness decreases from 21 km in the southwest to 10 14 km beneath the lapland granulite belt and the inari terrain reaching 20 km again in the extreme northeast the velocities also change laterally the thin lower crust is characterized by rather low velocities 6 8 6 9 km s whereas in the southwest and northeast the velocities 6 9 7 3 km s resemble more typical shield structures the moho is found at 47 km in the karelian province rises to 40 km beneath the lapland granulite belt and descends to 46 km in the northeastern part of the kola peninsula province the upper mantle velocities at the moho range from 8 1 km s in the region of the thin crust to 8 5 km s and more beneath the karelian province it is tempting to suggest that the anomalous lower crust underlying the lapland granulite belt and the inari terrain may represent the remnants of an early proterozoic back arc basin that was active prior to the 2 0 to 1 9 ga plate convergence event during which the lapland granulite belt was thrust onto the archaean basement of the karelian province another explanation is to assume that the velocity reduction in the anomalous lower crust was caused by a rather pronounced uplift of this region following the 1 9 ga collision event

studies of quasi horizontally propagating gravity waves in the troposphere using the piura st wind profiler vhf profiler observations of the troposphere obtained over a flat desert in northern peru show the presence of strong quasi sinusoidal oscillations in the vertical wind velocity with periods of around 8 18 min these oscillations are a very typical feature of the vertical velocities over piura this paper presents an overview of the wave characteristics obtained at piura until this point including results obtained using two additional antennas built a few hundred meters to the west and south of the main antenna to measure horizontal wavelengths and phase velocities briefly the piura waves appear to have horizontal wavelengths of 1 3 km with either westward or eastward phase velocities in a ground based reference frame of 0 5 4 m s 1 their occurrence appears to be causally related to the magnitude of the easterly wind which blows over the andean cordillera some 60 km to the east of the site

highly varying radiogenic heat production in finland fennoscandian shield abstract radiogenic heat production in finland has been previously studied using airborne gamma ray surveys and glacial till measurements alike for the first time this paper presents a detailed survey on the spatial variation in radiogenic heat production determined using outcrop samples obtained from all important lithologies of the country the dataset of 6465 samples represents mostly mesoarchean about 2 7 ga paleoproterozoic ca 2 2 1 8 ga and mesoproterozoic ca 1 6 1 3 ga rocks nearly all data are from precambrian fennoscandian shield area but heat production appears to be highly variable and above global archean and proterozoic averages spot readings show an arithmetic average of 1 34 1 19 wm 3 and a range from 0 02 to 19 4 wm 3 the interpolated areal average of the whole area is 1 42 1 41 wm 3 the high standard deviation of data is related to the geochemical characteristics of uranium u thorium th and potassium k resulting in a skewed distribution of heat production mesoproterozoic anorogenic rapakivi granites and late paleoproterozoic svecofennian granitoids show the highest heat production values in the range of 3 5 wm 3 the results show no distinct dependencies of heat production with geological age metamorphic grade nor seismic p wave velocity but an increasing trend of heat production with sio2 content and decreasing trends of heat production with fe2o3 content and with rock density are evident surface heat flow 44 borehole data values correlates weakly with heat production r 0 35 the general heterogeneity of heat production calls for supporting information from other geophysical methods for better understanding of the thermal state of the lithosphere in finland and beyond

petrology and geochemistry of mafic granulite xenoliths from the lahtojoki kimberlite pipe eastern finland abstract the lahtojoki kimberlite pipe in kaavi eastern finland contains lower crustal mafic granulite xenoliths with a mineral assemblage cpx amph pl grt opx bt the tweequ thermobarometry indicates crystallization at ca 800 900 c and 0 75 1 25 gpa which corresponds with crustal depths of ca 22 38 km reaction textures and results of thermobarometry in some xenoliths indicate post peak decompression with cooling chemical composition of the xenoliths suggest that their protoliths crystallized from basaltic melts with some k enrichment their ree patterns are slightly lree enriched some xenoliths having small negative eu anomalies the u pb ion probe dating of zircons from two samples yielded variable ages for zircons even in the same xenolith between ca 2 6 and 1 7 ga these ages correspond with main late archaean and palaeoproterozoic orogenic events in the fennoscandian shield the sm nd garnet clinopyroxene isochron age from one dated sample is 1 6 ga which represents either a cooling or reheating of the lower crust by rapakivi magmatism because the petrology geochemistry and ages of xenoliths do not correlate well with the nearest exposed archaean mafic granulites it is evident that the present lower crust underlying the archaean rocks has a considerable palaeoproterozoic component

computation of clear air radar backscatter from numerical simulations of turbulence 2 backscatter moments throughout the lifecycle of a kelvin helmholtz instability 1 franke et al 2011 describe a numerical simulation of the instability and turbulent breakdown of kelvin helmholtz kh billows at a high reynolds number numerical assessment of radar backscatter and accuracies of inferred doppler spectral moments for one test volume those results suggest a potential for significant measurement biases for radars that obtain backscatter from refractive index fluctuations we present in this paper the morphology of computed radar moments throughout the kh instability lifecycle for two radar configurations in order to reveal the evolving character of radar backscatter and compare the radar velocity estimates with true velocities throughout the evolution and to provide guidance and cautions for the interpretation of these dynamics in observational data results reveal strong variations in backscatter moments and character and dependence on radar measurement parameters that should be beneficial in the interpretation of such measurements in the atmosphere backscatter power predictions agree reasonably with observations of such events and their temporal evolutions our results also reveal a potential for significant measurement or sensitivity biases some of which were predicted previously examples include a lack of significant backscatter power in well mixed billow cores suggesting possibly weak turbulence where in fact it may be strongest maximum backscatter power in the billow exteriors where refractive index fluctuations are large but turbulence is weak underestimated vertical velocities within the kh billows at early times and inferred significant vertical velocities where true vertical velocities are near zero at late stages of restratification especially in the edge regions of the turbulence layer

detection of synoptic scale vertical velocities using an mst radar comparisons of the time averaged vertical velocity observations from the platteville co mst radar with synoptic scale vertical velocities computed by the adiabatic and quasi geostrophic omega equation methods are made for several case studies these first results show that an mst radar can detect synoptic scale vertical velocities and that at platteville the most favorable comparison occurs when the synoptic scale vertical velocity is large and the temporal variance of the mst radar data is small

multi stage origin of the lower crust of the karelian craton from 3 5 to 1 7ga based on isotopic ages of kimberlite derived mafic granulite xenoliths abstract mafic garnet granulite xenoliths recovered from 500 to 600 ma old eastern finland kimberlites provide direct information on the petrology and physical properties of the lower cust below the archean karelian craton mineral thermobarometry together with isotopic petrological and seismic velocity constraints imply that the xenolith suite is derived from a geophysically determined dense high velocity layer at the base of the crust 40 58 km depth single grain zircon u pb dates and nd model ages t dm imply that this is a hybrid layer consisting of both archean and proterozoic mafic granulites zircon ages of up to 3 5 ga and nd t dm model ages 3 7 ga of the xenoliths are equivalent to those of the oldest upper crustal assemblages during the proterozoic transient heating of these archean granulites by voluminous basic magmatic intrusions resulted in multiple younger zircon generations within individual xenoliths the most important post archean lower crust growth took place during 1 9 ga accretion of the svecofennian arc complex to the craton margin when underplating proterozoic basaltic magmas became mingled with pre existing archean mafic granulites later post orogenic 1 80 1 73 ga transient heating of the lower crust occurred as a response to magmas ponded at the uppermost lithospheric mantle in conclusion karelian lower crust records the geological evolution of the craton margin environment through a period of nearly 4 billion years our data add a new piece to the emerging picture that emphasises the global importance of the 3 5 ga crustal growth episode we suggest that it represents a major mantle plume event more widespread than previously recognized when a significant fraction of paleoarchean continental crust was formed

tropopausal mountain waves over arecibo a case study abstract vertically variable horizontal winds observd over arecibo by to and woodman which were previously interpreted as a manifestation of inertia gravity waves having intrinsic periods comparable to the local inertial period are reinterpreted as quasi stationary gravity waves of much shqrter intrinsic period induced orographically by airflow over the island and mountains of puerto rico the ellipticity of the viated halograph is attributed to an effect of background wind shears in the presence of such waves this new interpretation carries implicationsboth for the study of similar wind patterns elsewhere and for the reproducibility ofwind fields at arecibo where a natural laboratory for the study of mountain waves of critical layer interactions and of associated turbulence appears to be available

long term mean vertical motion over the tropical pacific wind profiling doppler radar measurements measurement from christmas island 2 n 157 w of long term mean vertical motions in the tropical atmosphere using very high frequency wind profiling doppler radar show that there is a transition from downward motion in the free troposphere to upward motion in the upper troposphere and lower stratosphere the observations in the free troposphere are consistent with a balance between adiabatic and diabatic heating and cooling rates in a clear atmosphere comparison of the results at christmas island during el nino and non el nino conditions with earlier results obtained for stratiform rain conditions over pohnpei federated states of micronesia show that cirrus clouds in the vicinity of the tropopause likely play an important role in determining the sense and magnitude of vertical motions in this region these results have implications for the exchange of mass between the troposphere and stratosphere over the tropics

discussion of stability of long trenches in sand supported by bentonite water slurry by george m filz tiffany adams and richard r davidson the authors have presented a valuable study on the stability of long slurry supported trenches in cohesionless soil quite by chance the discusser published a related paper two months ago fox 2004 the focus of that paper is the development of analytical solutions for trench stability under various conditions e g two dimensional 2d versus three dimensional 3d drained versus undrained cstrength whereas the focus of the current paper is largely on understanding stability mechanisms the two papers overlap in their analysis of 2d global stability of a slurrysupported trench with a fully formed filter cake in drained cohesionless soil both papers provide closed form equations for the factor of safety and orientation of the critical failure plane eqs 26 and 27 in fox 2004 and eqs 2 in the current paper the discusser has verified that the values of factor of safety and critical failure plane angle given by these equations are identical as stated by the authors the 2d global stability equations are appropriate for long trenches without significant end effects three dimensional stability effects that occur for shorter panels may yield substantially higher factors of safety to illustrate the discusser calculated the global factor of safety fs for various trench lengths l for the hypothetical example presented in fig 8 of the current paper using eqs 22 and 23 from fox 2004 in the notation used by fox 2004 the input parameters are as follows h hs 20 m zw 3 m zc 0 no tension crack

lithological interpretation of crustal composition in the fennoscandian shield with seismic velocity data abstract in this study we report the results of an investigation of lithological interpretation of the crust in the central fennoscandian shield in finland using seismic wide angle velocity models and laboratory measurements on p and s wave velocities of different rock types the velocities adopted from wide angle velocity models were compared with laboratory velocities of different rock types corrected for the crustal pt conditions in the study area the wide angle velocity models indicate that the p wave velocity does not only increase step wise at boundaries of major crustal layers but there is also gradual increase of velocity within the layers on the other hand the laboratory measurements of velocities indicate that no single rock type is able to provide the gradual downward increasing trends thus there must be gradual vertical changes in rock composition the downward increase of velocities indicates that the composition of the crust becomes gradually more mafic with increasing depth we have calculated vertical velocity profiles for a range of possible crustal lithological compositions the finnish crustal velocity profiles require a more mafic composition than an average global continental model would suggest for instance on the sveka 81 transect the calculated models suggest that the crustal velocity profiles can be simulated with rock type mixtures where the upper crust consists of felsic gneisses and granitic granodioritic rocks with a minor contribution of amphibolite and diabase in the middle crust the amphibolite proportion increases the lower crust consists of tonalitic gneiss mafic garnet granulite hornblendite pyroxenite and minor mafic eclogite assuming that these rock types are present in sufficiently extensive and thick layers they would also have sufficiently high acoustic reflection coefficients for generating the generally well developed reflectivity in the crust in the central part of the shield density profiles calculated from the lithological models suggest that there is practically no density contrast at moho in areas of the high velocity lower crust comparison of reflectors from fire 1 and fire 3 transects and the velocity model from sveka 81 wide angle transect indicated that the reflectors correlate with velocity layering but the three dimensional structures of the crust complicate such comparisons

high gravity wave activity observed in patagonia southern america generation by a cyclone passage over the andes mountain range fil pulido manuel arturo consejo nacional de investigaciones cientificas y tecnicas centro cientifico tecnologico conicet nordeste instituto de modelado e innovacion tecnologica universidad nacional del nordeste facultad de ciencias exactas naturales y agrimensura instituto de modelado e innovacion tecnologica argentina

inertia gravity waves observed by the uk mst radar we present an analysis of eight years data from the uk mst radar at aberystwyth wales to determine the occurrence and properties of long period quasi monochromatic oscillations in the wind vector identified with inertia gravity waves wave perturbations were first isolated by filtering out background wind variation in the vertical then the continuity of the radar measurements was exploited to apply band pass filters in time to select quasi monochromatic oscillations with periods 4 8 hours or 12 24 hours by searching for altitude regions where the wind vector rotates systematically with height and fitting ellipses to such sections the properties of inertia gravity waves can be derived to guard against contamination by short intrinsic period mountain waves cases were discarded when the vertical velocity measured by the radar exceeded 15 cm s 1 results show that waves in the stratosphere are dominated by upward energy propagation clockwise rotation and those in the troposphere by downward propagation consistent with the dominant source for inertia gravity waves being at tropopause level long period waves 12 hours are observed 70 of the time in the lower stratosphere roughly twice as often as the shorter period waves and 10 20 of the time in the troposphere there is a winter maximum in occurrence in the troposphere and for the short period stratospheric waves however the dominant long period waves show little seasonal dependence likewise they show only a weak correlation with jet stream velocity or direction unlike the other categories which are preferentially associated with strong jet streams and propagate along the jet inertia gravity waves observed by the radar have typical amplitudes 1 2 m s 1 and vertical wavelength 2 km the intrinsic wave period estimated for non jet stream conditions is similar for the two band passed series pointing to the importance of doppler shifting in generating the observed oscillations copyright 2007 royal meteorological society

three dimensional stability analysis for slurry filled trench wall in cohesionless soil on the basis of the limiting equilibrium and arching theory a three dimensional analysis is proposed for slurry supported trenches in cohesionless soils this analytical approach is developed by considering the trench stability problem as a vertical soil cut within a fictitious half silo with a rough wall surronding arching effects are considered not only in the vertical direction but also in the horizontal direction a shell shaped slip surface of the sliding soil mass is defined by mohr coulomb criterion the factor of safety is defines as the ratio of the resisting force induced by slurry pressure to the horizontal force required to maintain the stability of the trench wall results of the proposed method have been compared with those of two existing analytical methods for a typical trench stability problem key words stability analysis slurry trench wall cohesionless soil

bias in mean vertical wind measured by vhf radars significance of radar location relative to mountains abstract measurements by vhf wind profiling radars worldwide have for many years shown long term downward atmospheric motion in most of the troposphere various explanations have been proposed some atmospheric and some caused by the radar measurement method at many sites except those in the tropics the authors suggest a new model in which the long term downward vertical wind w is real and atmospheric a consequence of radars being constructed on low ground near or within mountain ranges so that they tend to view on average the same phase of mountain waves a coincidence consisting of five factors low lying radar locations near mountains the upwind slope of untrapped mountain wave phase lines with height the inability of wind profiling radars to measure both the lowest few kilometers of the troposphere and far into the stratosphere decreasing tropospheric static stability with height and increasing tropospheric wind speed with height has led to downward w measurements in most of the troposphe

direct measurement of large scale vertical velocities using clear air doppler radars abstract radars that can make wind measurements in the clear air are expected to play an increasing role in meteorological observing systems in the future especially for horizontal wind measurements this paper considers the prospects for using these radars which are sometimes called wind profilers to also measure the large scale vertical velocity unfortunately all radars for which vertical velocity data are available at this time are located in or near mountains where standing lee wave effects often make the data representative of only small scale features confining attention to those times when lee wave effects are not expected case study comparisons of the existing radar data with indirectly computed synoptic scale motions suggest that time averaged radar data are representative of large scale features smaller than the synoptic scale perhaps more aptly termed subsynoptic scale features results from a three station radar network in france show that the time averaged vertical velocities are usu

crust and upper mantle structure along the dss baltic profile in se finland summary the 430 km long dss baltic profile in se finland runs through the rapakivi intrusion the svecokarelian geosynclinal complex including the ladoga bothnian bay zone and the archean basement complex a brief description of field operations in 1982 is presented record sections of p and s waves were used for the interpretations a starting model was constructed by inverse methods and improved by dynamic ray tracing modelling three blocks are indentified on the cross section from sw to ne these are the southern associated with the rapakivi massif depth to moho m about 40 km the central ladoga bothnian bay zone with m of approximately 55 60 km and the northern archean crystalline basement with m about 40 45 km the average crustal velocity is 6 6 6 7 kms the crustal structure along the baltic profile is compared with the surrounding dss profiles finnish sveka and soviet kern tulos and ladoga profiles the eastern border of the ladoga bothnian bay zone was located and specific features of the crust and uppermost mantle along the profile area are discussed

on the downward bias in vertical velocity measurements by vhf radars eiscat vhf 224 mhz radar observations of the vertical velocity under polar mesosphere summer echo pmse conditions were performed with 2 s time and 300 m height resolution and velocity uncertainties better than 0 1 ms 1 we show that upward velocities that persist for 10 min or more lead to greater variance in the motion field and tend to make the pmse weaker as smaller radar cross section also correlates with larger velocity uncertainty any vertical mean velocity composed of thresholded radar data tends to have a downward negative bias we argue that this phenomenon can contribute to the discrepancy between the mean upwelling accounting for the summer mesopause thermal structure and radar observations of the mean vertical velocity

composition of the crust in the grenville and appalachian provinces of north america inferred from v p v s ratios we use the ratios between p and s wave velocities vp vs derived from seismic refraction data to infer the composition of the crust in the grenville and the appalachian provinces of north america the crust exhibits vp vs increasing with depth from 1 64 to 1 84 there is a clear distinction between the grenville province average vp vs 1 81 and the appalachian province average vp vs 1 73 which persists at all depths the boundary between these provinces is east dipping extending for 100 km east of the champlain thrust in the appalachian province the increase in vp vs ratios with depth from 1 67 to 1 74 0 02 may reflect a normal decrease of silica content in the continental crust in the grenville province beneath the central granulite terrane an anomalous vp vs ratio of 1 82 0 02 is observed extending to a depth of 10 km this correlates with the abundance of ca plagioclase in the marcy anorthosite at greater depth 15 20 km where seismic lamination and high electrical conductivity is observed vp vs is 1 84 0 02 and correlates with the tahawus complex a layered mafic intrusion within the 25 km thick lower crust of the grenville province the vp vs is 1 84 0 02 and p velocity is 7 0 0 1 km s which are typical for plagioclase bearing rocks gabbro norite the high vp vs ratio in the grenville province has not been reported in crust of any other age since the grenville province contains 75 of the world s known anorthosites high vp vs ratio is related to high plagioclase we suggest that the composition of the grenville lower crust was significantly modified by the emplacement of the anorthosites in the mid proterozoic

analytical solutions for stability of slurry trench coulomb type force equilibrium analyses are presented for general two and three dimensional stability of a slurry supported trench analytical solutions are derived for the factor of safety and critical failure plane angle in each case for drained effective stress and undrained total stress conditions the solutions can accommodate variable trench depth trench length slurry depth groundwater table elevation surcharge loading tension crack depth and level of fluid in the tension cracks drained analyses can account for c82f8 soil strength and the effect of soil suctions above the groundwater table using the total cohesion method undrained analyses can account for undrained shear strength that varies linearly with depth the solutions reduce to previously published expressions for simplified cases an example problem is provided to illustrate variations of the factor of safety and critical failure plane angle with the length of a three dimensional slurry trench finally the method shows excellent agreement with the results of a full scale field experiment of the failure of a diaphragm wall slurry trench constructed in silty sand

mountain waves in the tropical pacific atmosphere a comparison of vertical wind fluctuations over pohnpei and christmas island using vhf wind profilers abstract we compare vertical wind fluctuations observed by vhf radar wind profilers in the tropical troposphere over a large mountainous island pohnpei at 7 n 158 e and a large low profile atoll christmas island at 2 n 157 w the major difference in the two datasets appears to be due to the frequent occurrence of mountain waves over pohnpei and to their absence over christmas island these waves are generated continuously at low levels over pohnpei by the steady ene trade winds acting on the 800 m high terrain and can extend at least into the lower stratosphere we find the occurrence of mountain waves at middle and upper tropospheric levels over pohnpei to be governed primarily by a critical layer relationship between the winds aloft and the near surface winds a reversal in the direction of the upper level winds relative to the lower level trade winds precludes the upward propagation of mountain waves whereas a nonreversed wind profile allows the waves to propagate freely into the lower s

composition of the uralide crust from seismic velocity v p v s heat flow gravity and magnetic data abstract p wave velocity vp s wave velocity vs poisson s ratio heat flow potential field and surface geological data are integrated to constrain a model for the composition of the uralide crust along the urseis transect the model is constructed using published laboratory measurements of vp vs and density for a variety of crustal rock types these laboratory data have been corrected for depth pressure and the uralides temperature depth function the model shows clear differences between the composition of the old continental crustal nucleus of the east european craton and the newly added crust of the accreted arc terranes to the east the crust of the east european craton is more felsic than that of the magnitogorsk and east uralian zones and the latter two have a lowermost crust whose characteristics indicate a high garnet content mafic garnet granulite and or the presence of hornblendite the overall composition of the arc terranes is basaltic physical properties suggest that eclogite is not present in the arc terranes or if present it exists in small amounts that are below the resolution of the data set the lack of eclogite in the lower crust favours an intracrustal differentiation model for the evolution of the bulk composition of the continental crust nevertheless the absence of surface uplift the lack of metamorphism and late orogenic mantle melts and the current crustal thickness indicate that crustal thinning did not affect the bulk composition of the uralide crust

analog modeling of one way gravitational spreading of hot orogens a case study from the svecofennian orogen fennoscandian shield abstract geodynamic models offer insight into deformation styles of syn and post collisional extensional processes such models often ignore the effect of lateral viscosity contrast between accreted terranes and inherited tectonic boundaries this paper presents a set of crustal scale analog experiments of one way post collisional gravitational spreading testing the effect of crustal heterogeneity by using two mechanically contrasting blocks pre existing cuts with varying dips and three layers with contrasting rheologies two blocks represent strong mature and weak juvenile crustal parts both blocks have three horizontal crustal layers brittle upper weak partially molten middle and dry strong lower layer cuts represent pre existing crustal scale shear zones and tectonic boundaries the experiments indicated that tectonic boundaries may facilitate exhumation and increase extensional strain when the boundaries dip opposite to the flow direction the tectonic boundaries may also split and divide the crust into separate blocks with independent deformation signatures shortening elongation or rotation the tectonic boundaries rotated along vertical axes toward the flow direction the modeling results suggest that in areas with inherited tectonic boundaries and compositional differences the amount of extension is unevenly distributed between the different parts during the widespread unilateral gravitational spreading and that the flow has different effects on the contrasting crustal units in both lateral and vertical directions to validate the modeling the results are compared to geophysical and geological data from the paleoproterozoic svecofennian orogen in the fennoscandian shield the comparison suggests that the orogen underwent 50 extension and was thinned by maximum of 20 via westward gravitational spreading this spreading rotated the crustal scale blocks shear zones and tectonic contacts it also brought exhumed high grade middle crustal blocks into contact with subsided low grade upper crustal blocks we suggest that results of the analog models can be used as proxies in both ancient and modern hot accreted orogens which have undergone post convergence continental mid crustal weakening and have comprised of juxtaposed terranes with varying rheological compositions

three stages to form a large batholith after terrane accretion an example from the svecofennian orogen abstract the magmatic history of batholiths formed as the result of tectonic accretion mirrors the evolution of the underlying crust from island arcs to accretion and collapse chemical composition age and structure give information about the magma source and emplacement depths the target of this study is the central finland batholith cfgc that provides a magmatic record after terrane accretion during the svecofennian orogeny followed by orogenic collapse the crustal source of partial melting has changed during the crustal evolution and differentiation after the terrane accretion and when the stress regime has changed from contraction to extension here we present a three stage magmatic evolution model for accretional batholith in the svecofennian orogen in the first stage the lower crust of the accreted crust melts partially and produces calcic tonalitic melts that are emplaced above the upper middle crustal detachment zone group 1 1887 3 ma in the second stage the middle crust begins to melt producing calc alkalic granodioritic melts that are emplaced close to the surface group 2 1890 1886 ma and at both sides of the upper middle crustal detachment zone group 2 1884 1883 ma in the third stage the lower crust remelts and produces bimodal calc alkalic gabbroic and alkali calcic to alkalic granitic melts group 3 1881 1880 ma which are emplaced above the upper middle crustal detachment zone this kind of crustal differentiation produces a mafic lower an intermediate middle and a felsic upper crust the third stage represents the last magmatic event of the svecofennian accretional orogeny where the high velocity lowermost crust is formed during this stage crustal thickening and widespread mid crustal partial melting have inititated lateral flow after or concurrently with the emplacement of the group 2 granodiorite the lateral flow has reactivated large scale shear zones allowing the transportation of the group 3 rocks from the lower crust to the upper middle crustal detachment zone the change in the degree of deformation at the exposed parts from undeformed through local to pervasive is attributed to differences in the exhumation level

observations of a reversal in long term average vertical velocities near the jet stream wind maximum abstract analysis of vertical velocity measurements made for four days each month over the period from 1986 to 1988 by the mu radar in japan shows a reversal in direction near the peak in the zonal wind profile during the winter months more specifically the reversal is noted during periods when the peak horizontal wind speeds 60 m s 1 the vertical velocities associated with the circulation have magnitudes of 10 20 cm s 1 and the depth of the circulation is of the order of several kilometers in 6 out of 14 cases when the feature was observed the direction of the vertical circulation although not the magnitude could be explained by adiabatic ascent or subsidence along the average potential temperature surface slopes for the observation intervals the direction of the circulation was such that it would tend to produce cooling and heating for the ascent and subsidence respectively that would tend to strengthen or at least maintain the jet in the remaining eight cases the direction of the vertical

first frequency domain interferometry observations of large scale vertical motion in the atmosphere the spatiotemporal distribution of the vertical velocity at synoptic and subsynoptic scales is key to the patterns of weather and climate on earth on these scales the vertical velocity is on the order of one to a few centimeters per second typically about three orders of magnitude smaller than typical horizontal wind velocities because of the smallness of large scale vertical velocities relative to typical horizontal velocities a direct observation of the large scale vertical air velocity is extremely difficult in a case study on observational material obtained during a 68 h experiment using the sousy very high frequency vhf radar in the harz mountains in germany the authors present the first intercomparison between three different sources of physical information that can provide large scale vertical wind velocities i the doppler shifts observed with a vertically pointing vhf radar ii the rates of change of the altitudes of refractiveindex discontinuities as identified with frequency domain interferometry fdi which is still a relatively unexplored technique in meteorology and iii the output of a regional numerical weather prediction model nwpm which has been set up to model the meteorological situation during the observational period there are several phenomena that have been known to possibly cause significant biases in mean vertical velocities retrieved from the doppler shifts measured with vertically pointing clear air vhf radars i stationary or nonstationary gravity waves with vertical velocity amplitudes up to the order o f1ms 21 ii stationary or horizontally advected tilted refractive index discontinuities that are aspect sensitive in the vhf regime and iii a correlation between the radar reflectivity fluctuations and the vertical velocity fluctuations within a vertically propagating gravity wave on the basis of an intercomparison between the vertical velocities retrieved from i standard doppler vhf radar observations ii vhf fdi observations and iii the nwpm output the authors present first evidence that under ideal conditions vhf fdi can be used to directly monitor large scale vertical motion

mean vertical motions and their time height variations in the lower troposphere obtained from a uhf wind profiler at pune a tropical indian station 1 a 404 mhz wind profiler uhf radar system has been in continuous operation since june 2003 at pune 18 32 n 73 51 e a tropical indian station the system enables measurement of all three components zonal meridional and vertical of the wind field with height coverage from 1 05 km to about 10 km and a height resolution of 300 m daily mean profile data of vertical velocity in the lower troposphere obtained during the 3 year period june 2003 to may 2006 has been used in this study to investigate the long term mean clear air vertical velocity its variability and seasonal intraseasonal variations mean vertical velocities varied between 5 30 cm s 1 and 1 30 cm s 1 and mean vertical motions are predominantly downward at altitudes above 3 km significant seasonal variation in vertical velocity has been observed during southwest monsoon months june september a vertical two cell structure in vertical velocity has been noticed with upward motions below 4 km and downward motion above in the premonsoon months march may vertical motions are predominantly downward throughout the lower troposphere variability is larger during the monsoon and premonsoon seasons and is smaller during postmonsoon october november and winter december february seasons vertical velocities at altitudes below 3 km reveal significant semiannual and annual oscillations mean diurnal variations during sw monsoon period show interesting features the observed variability in vertical velocities especially in layers close to the surface is explained to be due to the highly variable weather conditions on local as well as synoptic scale at this tropical station

convection waves observations of gravity wave systems over convectively active boundary layers widespread gravity wave systems have been found to exist over convectively active boundary layers cbls in the presence of vertical wind shear in contrast to mountain waves these convection waves occur over flat terrain and are ubiquitous over fields of shallow fair weather cumuli or clear air thermals they extend vertically to at least 9km a m s l probably to the tropopause first discovered by glider pilots as thermal waves they have now been systematically investigated by research aircraft during the ncar convection wave project which also incorporates an effort in numerical simulation the flight results are reported in this paper while the numerical simulations are described in a companion paper typical wavelengths of convection waves were found to range from 5 to 15 km average 9 km and typical vertical motion amplitudes from 1 to 3 m s 1 in all cases vertical wind shear exceeded 3 10 3s 1 under these conditions cloud tops were measured to move with relative velocities of 8 to 10 m s 1 against their environment hence they present an obstacle to the surrounding airflow the analogy to mountainous obstacles launching gravity waves into the atmosphere is suggestive and borne out by the aforementioned numerical simulations which describe this process step by step the interaction between the cbl and the overlying stable layers is studied by spectral and cross spectral analysis of aircraft data including coherence and phase relations between wave motions and cloud population underneath consideration is given to other potential sources of the observed gravity waves at this stage the conclusions of our pilot study may be considered tentative some implications for further research are also discussed

laboratory measurements of the seismic velocities and other petrophysical properties of the outokumpu deep drill core samples eastern finland summary petrophysical in particular seismic velocity measurements of the outokumpu deep drill core depth 2 5 km have been carried out to characterize the geophysical nature of the paleoproterozoic crustal section of eastern finland and to find lithological and geophysical interpretations to the distinct crustal reflectors as observed in seismic surveys the results show that different lithological units can be identified based on the petrophysical data the density of the samples remained nearly constant throughout the drilled section only diopside tremolite skarns and black schists exhibit higher densities the samples are dominated by the paramagnetic behaviour with occasional ferromagnetic signature caused by serpentinitic rocks large variations in seismic velocities both at ambient pressure and under in situ crustal conditions are observed the porosity of the samples which is extremely low is either intrinsic by nature or caused by decompaction related to fracturing during the core retrieval it is noteworthy that these microfractures have dramatically lowered the vp and vs values from the measured velocities and density data we have calculated the seismic impedances young s modulus and poisson s ratios for the lithological units of the outokumpu section and from these data the reflection coefficients for the major lithological boundaries evident in the surveyed section were determined the data show that the strong and distinct reflections visible in wide angle seismic surveys are caused by interfaces between diopside tremolite skarn and either serpentinites mica schist or black schist

receiver function analysis of the crust and upper mantle in fennoscandia isostatic implications abstract the mountains across southern norway and other margins of the north atlantic ocean appear conspicuously high in the absence of recent convergent tectonics we investigate this phenomenon with receiver functions calculated for seismometers deployed across southern fennoscandia these are used to constrain the structure and seismic properties of the lithosphere and primarily to measure the thickness and infer the bulk composition of the crust such parameters are key to understanding crustal isostasy and assessing its role or lack thereof in supporting the observed elevations our study focuses on the southern scandes mountain range that has an average elevation 1 0 km above mean sea level the crust mantle boundary moho is ubiquitously imaged and we occasionally observe structures that may represent the base of the continental lithosphere or other thermal chemical or viscous boundaries in the upper mantle the moho resides at 25 30 km depth below mean sea level in southeastern coastal norway and parts of denmark 35 45 km across the southern scandes and 50 60 km near the norwegian swedish border that section of thickest crust coincides with much of the transscandinavian igneous belt and often exhibits a diffuse conversion at the moho which probably results from the presence of a high wave speed mafic lower crust across inner fennoscandia a zone of thinned crust

pds receiver function evidence for crustal scale thrusting relic subduction and mafic underplating in the trans hudson orogen and yavapai province a b s t r a c t article history the trans hudson orogen tho in the north central united states represents a major suturing event between the wyoming and superior archean provinces it is bounded to the south by the ne sw striking yavapai province which was accreted along the southeastern margin of north america between 1 71 and 1 68 ga and was one of a series of major collisional events responsible for the assembly of laurentia in this study pds teleseismic receiver functions were used to investigate the deep crustal structure associated with these collisions using data from over 800 broadband seismic stations distributed throughout the great plains midcontinent region we calculated 0 5 hz receiver functions using 245 m 6 0 teleseismic events the receiver functions were then ccp common conversion point stacked to create a 3d image volume profiles through this image volume show evidence of crustal scale thrusting of the wyoming province in the west over the superior province in the east and a relic subduction zone associated with the yavapai superior boundary we also performed a density analysis of the region using relative amplitude of the 2p1s and 0p1s receiver function phases from 233 stations these data indicate a relatively low moho density contrast throughout the tho and northern yavapai province associated with a region of thickened crust 50 km which we interpret to be evidence of a dense lower crustal layer that is the result of mafic underplating