site investigations to evaluate flow liquefaction slides at sand heads fraser river delta l ecoulement par liquefaction spontanee est un processus recurrent dans la progradation du delta du fleuve fraser une portion du delta a ete etudiee au moyen d essais de penetration au cone sismique et de resistivite et au moyen de l analyse spectrale de la methode des ondes de surface et de l echantiollonage de sol et de vapeur dans un effort pour determiner la stratigraphie du site l etat in situ et le degre de saturation afin explorer l enigme de l ecoulement par liquefaction spontanee un ensemble de capteur de pression interstitielle et d inclinaison a ete installe comme partie de l etude pour mesurer les effets de la vidange resultant du reflux de la maree les resultats ont indique que le lit de la mer a faible profondeur etait partiellement sature contenant un volume significatif de gaz methane qui affectait la reponse dynamique de la pression interstitielle durant le jusant une reduction de la contrainte effective atteignant 16 5 kpa a ete mesuree de meme qu un delai de 50 min entre le reflux de la maree et la reaction de la pression interstitielle ceci suggere que les effets de tampon sont un facteur significatif dans le declenchement de la liquefaction spontanee des sables l ches non viellis la ou ils reposent sur des pentes sous marines les resultats des essais in situ montrent que les sables nouvellement deposes du fleuve fraser ont une forte susceptibilite a l ecoulement par liquefaction

aqueous and mineralogical analysis of arsenic in the reduced circumneutral groundwater and sediments of the lower fraser river delta british columbia canada abstract naturally occurring as in the groundwater and holocene sediments of the lower fraser river delta was studied at each of two sites in the delta vertical profiles of groundwater geochemistry were characterized and sediment cores were collected for petrographic analysis quantification of elemental abundances and sequential extraction analysis to characterize the pools of solid phase as total solid phase as concentrations were similar to those found in other deltaic environments ranging from 2 2 to 2 6 g g at a site of groundwater recharge with approximately 4 m of peat at the surface to 2 7 4 1 g g at a site adjacent to the fraser river where saline water is encountered within the aquifer at depth arsenic that was weakly bound or could be mobilized by reduction of fe oxides constituted between 20 and 50 of the total as in the sediments groundwater as concentrations showed distinct vertical trends and peaked at 9 g l at the peat influenced site and between 29 and 32 g l at the site with saline water at depth at both sites reduction of dissolved organic matter appears to be responsible for reducing conditions high dissolved fe up to 230 mg l high hco 3 and the presence of nh 4 and po 4 3 the peat impacted site implies that a direct source of dissolved organic c from peat is not a sufficient condition for significant as release into groundwater in the fraser river delta

late quaternary sea levels and crustal movements coastal british columbia late quaternary sea level fluctuations on the british columbia coast have been established from studies of terrestrial and marine sediments and landforms these studies indicate that the sea level history of mainland british columbia and eastern vancouver island is very different from that of the queen charlotte islands and western vancouver island specifically in the former areas there was a rapid rise of submerged coastal lowlands between about 13 000 and 10 000 years ago emergence culminated about 6000 9000 years ago depending on the locality when the sea relative to the land was 12 m or more lower than at present in some areas during middle and late holocene time relative sea level rose on the mainland coast and at least locally on eastern vancouver island resulting in inundation of coastal archaeological sites and low lying terrestrial vegetation tidal records and precise levelling suggest ongoing submergence of at least part of this region in contrast shorelines on the queen charlotte i

age and significance of earthquake induced liquefaction near vancouver british columbia canada in late 1994 sand dykes large sand blows and deformed strata were exposed in the walls of an excavation at annacis island on the fraser river delta near vancouver british columbia the features record liquefaction during a large earthquake about 1700 years ago this was perhaps the largest earthquake to affect the vancouver area in the last 3500 years similar less well dated features have been reported from several other sites on the fraser delta and may be products of the same earthquake three radiocarbon ages that closely delimit the time of liquefaction on annacis island are similar to the most precise radiocarbon ages on coseismically subsided marsh soils at estuaries in southern washington and oregon both the liquefaction and the subsidence may have been produced by a single great plate boundary earthquake at the cascadia subduction zone alternatively liquefaction at annacis island may have been caused by a large crustal or subcrustal earthquake of about the same age as a plate boundary earthquake farther west the data from annacis island and other sites on the fraser delta suggest that earthquakes capable of producing extensive liquefaction in this area are rare events further liquefaction analysis using historical seismicity suggests that current assessment procedures may overestimate liquefaction risk

upper crustal structure beneath the strait of georgia southwest british columbia summary we present a new three dimensional 3 d p wave velocity model for the upper crustal structure beneath the strait of georgia southwestern british columbia based on non linear tomographic inversion of wide angle seismic refraction data our study part of the georgia basin geohazards initiative gbgi is primarily aimed at mapping the depth of the cenozoic sedimentary basin and delineating the near surface crustal faults associated with recent seismic activities e g m 4 6 in 1997 and m 5 0 in 1975 in the region joint inversion of firstarrival traveltimes from the 1998 seismic hazards investigation in puget sound ships and the 2002 georgia basin experiment provides a high resolution velocity model of the subsurface to a depth of 7 km in the southcentral georgia basin sedimentary rocks of the cretaceous nanaimo group and early tertiary rocks have seismic velocities between 3 0 and 5 5 km s 1 the basin thickness increases from north to south with a maximum thickness of 7 1 km depth to velocities of 5 5 km s 1 at the southeast end of the strait the underlying basement rocks probably representing the wrangellia terrane have velocities of 5 5 6 5 km s 1 with considerable lateral variation our tomographic model reveals that the strait of georgia is underlain by a fault bounded block within the central georgia basin it also shows a correlation between microearthquakes and areas of rapid change in basin thickness the 1997 1975 earthquakes are located near a northeast trending hinge line where the thicknesses of sedimentary rocks increase rapidly to the southeast given its association with instrumentally recorded moderate sized earthquakes we infer that the hinge region is cored by an active fault that we informally name the gabriola island fault a northwest trending southwest dipping velocity discontinuity along the eastern side of vancouver island correlates spatially with the surface expression of the outer island fault the outer island fault as mapped in our seismic tomography model is a thrust fault that projects directly into the lummi island fault suggesting that they are related structures forming a fault system that is continuous for nearly 90 km together these inferred thrust faults may account for at least a portion of the basement uplift at the san juan islands

holocene sea level change and delta growth fraser river delta british columbia the fraser river has been building its delta into the strait of georgia in southwestern british columbia for about the last 9000 years this period encompassed a relative sea level rise of some 13 m this study concerns the effects of the rise in sea level on the depositional evolution of the delta the lithostratigraphy of the delta was established by a series of drill cores four major lithostratigraphic units were defined peat organic rich silt interbedded silts and sands and massive sands these units were interpreted in terms of the delta s contemporary depositional environments including peat bog floodplain and intertidal zone analysis of the delta s depositional architecture and chronology indicates that the delta continued to prograde during the rise in sea level a marine transgression accompanied by the landward migration of marine and intertidal facies did not occur growth of the delta during the rise in sea level was accomplished by both vertical accretion and lateral progradation ver

the seismic facies of a tidally influenced holocene delta boundary bay fraser river delta b c abstract the tidally influenced fraser river delta in southwestern british columbia is actively prograding into the strait of georgia to investigate the geometry stratigraphy and structure of the post glacial fraser river delta sediments a high resolution shallow seismic reflection survey was carried out during the summer of 1987 in the boundary bay region of the delta twenty kilometers of optimum offset seismic reflection data were collected these high resolution seismic profiles were shot with 3 m spacing between geophones and a two way travel time of 200 ms four seismic facies were identified representing foreset topset slope failure and distributary channel deposits the foreset seismic facies has reflections that dip at angles of 1 to 7 towards boundary bay along strike the reflections have horizontal or mounded patterns horizontal continuous reflections typify the topset seismic facies the slope failure facies is located within the foreset seismic facies and consists of upper convex reflections and broken internal reflections the distributary channel seismic facies is characterized by concave downward reflections and is incised into the top of the foreset facies

provenance stratigraphic architecture and hydrogeologic influence of turbidites on the mid ocean ridge flank of northwestern cascadia basin pacific ocean abstract the northwestern edge of cascadia basin north pacific ocean is unusual because late pliocene to holocene turbidites lap onto juvenile oceanic crust of the juan de fuca ridge subsidence of the ridge flank combines with irregular westward progradation of the turbidite facies to create a stratigraphic section that coarsens and thickens upward the sand provenance is mixed individual turbidity currents have funneled into the area through several shelf slope and abyssal floor conduits including vancouver valley juan de fuca channel barkley canyon and nitinat canyon local bathymetric blockage deflection and reflection of flow paths by basement relief remobilization by intrabasinal submarine slides and debris flows episodic channel switching and sporadic overbank flooding have combined to produce erratic recurrence intervals for the turbidity currents only the tallest basement highs have remained isolated from turbidite deposition during the last 500 000 years spatial and temporal differences in sediment accumulation are important because they modulate the three dimensional responses of compaction and consolidation those changes in physical properties govern where and when hydraulic communication with the underlying basement shuts down the basal hemipelagic layer of cascadia basin transforms to an effective hydrologic seal seepage rates 1 mm yr once the sediment basalt interface is buried by 100 150 m of strata rapid accumulation of turbidites therefore accelerates the hydrogeologic conversion of igneous basement from open to sealed

sedimentary environments and postglacial history of the fraser delta and lower fraser valley british columbia the fraser river delta which is about 1000 km2 in area above low tide level has been built into the strait of georgia in southwestern british columbia during the holocene present day sedimentary

a delta plain sheet sand in the fraser river delta british columbia canada abstract borehole data in the fraser river delta demonstrate that a nearly continuous sand unit generally 8 to 20 m thick underlies the surficial silts and sands of most of the delta plain the sand unit consists of one or more sharp based fining upward sequences and is interpreted to be a complex of distributary channel deposits distributary channel migration and the resulting accumulation of channel sands has occurred primarily in a tidal flat environment due to the interaction of tidal and fluvial processes and the high proportion of sand in the sediment load this sand unit thus provides a model for sand rich river and tide dominated delta plains jetties now maintain the position of the main channel of the fraser river where it crosses the tidal flats and prevent channel migration and further storage of sand in the lower delta plain as a result more of the available sand is being transported directly to the river mouth where failures transport the sand downslope consequently these structures contribute to instability at the river mouth

dynamic characteristics of the yellow river mouth the yellow river delta is dynamic because the river carries a heavy sediment load and serious siltation occurs in the area massive sediment transport brings fertile soil to the river mouth leading to its expansion by 20 25 km2 per year the dramatic reduction in runoff and sediment in the delta due to increasing water demand has extended the period of flow cut off the river changes its delta channel about once every ten years the channel shifts affect the upstream flood stages since the river shifted to the present delta channel in 1976 the shape of the delta has changed remarkably sediment laden flow has been building channels by depositing sediment in low velocity areas and has extended the river mouth into the sea for more than 40 km the velocity of sea currents is enhanced by the growth of the river mouth spit at a rate of 1 m s 1 per 10 km extension which results in high capacity of sea currents carrying sediment away from the mouth the new river mouth area was silted up by 14 m and the old river mouth area was eroded by 5 m siltation takes place in the low flow season and scouring occurs in the flood season scouring occurs during the rising limb of a flood and siltation occurs during the receding limb of a flood the roughness of the river changes largely following the increase in discharge the minimum manning roughness occurs at non siltation and non erosion discharge tidal influence in the river is restricted to a section extending over only a few kilometres unlike in many other coastal areas the river water with its high sediment concentration develops into density current and flows underneath the seawater during flood this mechanism contributes to sediment transportation in the delta copyright 2000 john wiley sons ltd

pre and post missoula flood geomorphology of the pre holocene ancestral columbia river valley in the portland forearc basin oregon and washington usa abstract geomorphic landscape development in the pre holocene ancestral columbia river valley 1 5 km width in the portland forearc basin 50 km length is established from depositional sequences which pre date and post date the glacial lake missoula floods the sequences are observed from selected borehole logs 150 in number and intact terrace soil profiles 56 in number in backhoe trenches four sequences are widespread including 1 a vertically aggraded pleistocene alluvial plain 2 a steep sided valley that is incised 125 150 m into the pleistocene gravel plain 3 missoula flood terraces 19 13 ka abandoned on the sides of the ancestral valley and 4 holocene flooding surfaces 11 8 ka buried at 70 30 m depth in the axial columbia river valley weathering rims and cementation are used for relative dating of incised pleistocene gravel units soil development on the abandoned missoula flood terraces is directly related to terrace deposit lithology including thin bw horizons in gravel irregular podzols in sand and multiple bw horizons in thicker loess capping layers radiocarbon dating of sand and mud alluvium in the submerged axial valley ties holocene flooding surfaces to a local sea level curve and establishes holocene sedimentation rates of 1 5 cm year 1 during 11 9 ka and 0 3 cm year 1 during 9 0 ka the sequences of pleistocene gravel aggradation river valley incision cataclysmic missoula flooding and holocene submergence yield complex geomorphic landscapes in the ancestral lower columbia river valley

rapidly accelerating subsidence in the greater vancouver region from two decades of ers envisat radarsat 2 dinsar measurements abstract rapidly accelerating ground subsidence in the south western part of british columbia the third largest metropolitan area in canada with over 2 3 million of inhabitants is estimated using the multidimensional small baseline subset msbas advanced differential interferometric synthetic aperture radar dinsar an effective processing strategy for multi mission multi temporal sar data the synthetic aperture radar sar data used in this study consists of seven independent data sets one ascending and one descending ers 1 2 and envisat frames together spanning july 1995 september 2010 and three radarsat 2 frames spanning february 2009 october 2012 during the july 1995 october 2012 period we observe fast ground subsidence with a maximum rate of about 2 cm year in the greater vancouver region that includes the fraser river delta and the cities of burnaby richmond surrey new westminster and vancouver the rapidly accelerating subsidence is observed beneath the vancouver international airport skytrain terminal as well as several agricultural and industrial locales these time series suggest that the subsidence rate at the studied regions does not decrease with time as suggested in previous studies but remains steady or increases these results also demonstrate the importance of acquiring and appropriately estimating longer time series as previous studies on the same greater vancouver area may have misinterpreted the long term ground deformation rate and direction and underestimated the potential hazard the long term impact of this subsidence on urban infrastructure can be significant and needs to be investigated further

the foreslope hills large scale fine grained sediment waves in the strait of georgia british columbia abstract the foreslope hills are a set of 20 m high 5 km long ridges at 230 350 m water depth in the south central strait of georgia occupying a 60 km 2 area at the base of the fraser river delta foreslope they are composed of clay silt and fine sand previous authors have interpreted them as 1 a single mass slide deposit 2 mud diapirs 3 in situ rotational failures and 4 creep deformation features but collaborative evidence for these interpretations is lacking seafloor surface morphological renders derived from recent multibeam sonar bathymetry data show linear evenly spaced symmetrical ridges with ridge bifurcation resembling wave ripples but on a much larger scale detailed multichannel and single channel seismic reflection data show sinusoidal internal reflections suggesting upslope migration the ridges occur within the uppermost portion of the holocene section in a very high sedimentation rate environment consequently they are probably less than 3000 years old moored current meter records for the region show reversing currents largely oriented normal to the ridge crests averaging 10 cm s with a maximum of 50 cm s this evidence combined with increasing documentation of large scale sedimentary bedforms in slope and rise environments suggests that the foreslope hills should be re interpreted as sediment waves upslope migration is typical of many large scale fine grained sediment waves the preferred physical interpretation for the creation and maintenance of the foreslope hills as sediment waves is the lee wave model requiring a phase shift in density stratified flow as it passes over the wavy topography maximum measured bottom currents are easily strong enough to entrain silt and clay delivered to the site by turbidity currents or by sediment plume fallout from fraser river outflow either strong flood tides or severe biannual density intrusions due to their intense stratification may be susceptible to lee wave formation and the creation of sediment waves leading to the observed pattern of upslope migration

origin and variability of sedimentary facies of the fraser river delta foreslope british columbia abstract five sedimentary facies have been recognized in piston cores from the fraser river delta foreslope 1 river plume suspension deposited massive silty clay with minor organics 2 suspension deposited silty clay to clayey silt with rare parallel silt and very fine sand laminations deposited under minor traction 3 clayey silt with silt or very fine sand interbeds from mixed suspension and low density turbidity current traction deposition 4 silty very fine to medium grained sand with less than 10 thin clay or silt interbeds predominantly deposited from high density turbidity currents and 5 organic rich disorganized chaotic beds facies distribution patterns suggest that the fraser delta foreslope is dissected by a number of both active and inactive channels these channels have served as a mechanism for coarse grained sediment to bypass the delta plain and upper foreslope and be introduced directly to the lower foreslope and basin floor it is hypothesized that these channels debouch as a series of depositional lobes and slump related failure deposits in the prodelta basinal environment the direct introduction of clastic sediment into water depths exceeding 250 m suggests a process analogue for the interpretation of shelf edge deltas in the rock record thus the fraser river delta may offer a unique opportunity to model active sedimentation associated with a lowstand of sea level

geomorphology and potential slope instability on the fraser river delta foreslope vancouver british columbia le delta du fleuve fraser est localise dans une des regions ayant les plus hauts risques sismiques au canada et comprend pour une bonne part des sables fluviaux meubles tres connus comme possedant un potentiel eleve de liquefaction sismique des etudes recentes de la rive ouest du delta du fraser indiquent que la liquefaction cyclique durant un fort tremblement de terre est possible engendrant potentiellement des deformations incluant des extensions laterales un ramollissement cyclique et possiblement une coulee l on presente une evaluation preliminaire de la stabilite statique des pentes apres secousse dans laquelle les analyses ont ete limitees aux valeurs estimees des resistances au cisaillement ultimes ou a l etat d equilibre deduites de correlations avec les donnnees du terrain et aux contraintes de cisaillement calculees en partant de la bathymetrie du lit de mer existant l on a trouve que le coefficient postliquefaction de securite contre le glissement etait inferieur a l unite pour la pente de la terrasse superieure roberts en supposant une limite inferieure de resistance au cisaillement ultime equivalente a 0 06 p 0 les donnees pour evaluer la validite de cette hypothese sont insuffisantes cependant il y a abondance de depots de rupture le long de la base de la pente du delta

palaeosols in westphalian coal bearing and red bed sequences central and northern england westphalian a c coal bearing strata and red beds in the pennine basin of central and northern england contain a wide variety of palaeosols in coal bearing facies associations alluvial gley semi gley organic and rare well drained palaeosols reflect the predominance of poor drainage conditions during deposition in red beds more evolved ferruginous and ferallitic palaeosols testify to free drainage conditions during deposition catenary relationships can be inferred between most of the palaeosols in both facies associations providing further information on the palaeogeomorphology of the depositional systems and assisting in the understanding of the environments and conditions of coal seam formation

the isotope geochemistry of carbon in groundwater at stripa the carbon isotopic composition of the total dissolved inorganic carbon in groundwater associated with a granitic pluton at stripa sweden reflects both inorganic and organic carbon sources following the uptake of soil carbon dioxide calcite dissolution dominates the geochemical evolution of shallow groundwater calcite saturation is reached at a depth of about 100 m in deeper waters geochemical release of ca and increasing ph cause calcite precipitation radiocarbon contents suggest carbon and water ages in excess of 20 000 years for waters at 300 400 m depth in deep groundwaters with enhanced salinities organic carbon is added to the dissolved inorganic carbon either through bacterial activity e g sulphate reducing bacteria or the oxidation of organic compounds such as methane the lowest radiocarbon contents were measured at the 300 400 meter levels and not in the deepest fluids the distribution of 13c in the deep groundwaters suggests the existence of well defined flowsystems with limited active hydraulic interaction isotope analyses on fracture calcites substantiate the complex geochemical history of the pluton

record of large late pleistocene outburst floods preserved in saanich inlet sediments vancouver island canada abstract two anomalous gray silty clay beds are present in odp cores collected from saanich inlet vancouver island british columbia canada the beds which date to about 10 500 14c yr bp 11 000 calendar years bp contain tertiary pollen derived from sedimentary rocks found only in the fraser lowland on the mainland of british columbia and washington just east of the strait of georgia abundant illite muscovite in the sediments supports a fraser lowland provenance the clay beds are probably distal deposits of huge floods that swept through the fraser lowland at the end of the pleistocene muddy overflow plumes from these floods crossed the strait of georgia and entered saanich inlet where the sediment settled from suspension and blanketed diatom rich mud on the fiord floor the likely source of the floods is late pleistocene ice dammed lakes in the fraser and thompson valleys which are known to have drained at about the time the floods occurred

basin architecture and density structure beneath the strait of georgia british columbia georgia basin is located within one of the most seismically active and populated areas on canada s west coast over the last decade geological investigations have resolved important details concerning the basin s shallow structure and composition yet until recently relatively little was known about deeper portions of the basin in this study new seismic velocity information is employed to develop a 3 dimensional density model of the basin comparison of the calculated gravity response of this model with the observed gravity field validates the velocity model at large scales at smaller scales several differences between model and observed gravity fields are recognized analysis of these differences and correlation with independent geoscience data provide new insights into the structure and composition of the basin fill and underlying basement specifically four regions with thick accumulations of unconsolidated pleistocene and younger sediments which were not resolved in the velocity model are id

optical dating studies of quaternary organic rich sediments from southwestern british columbia and northwestern washington state the suitability of optical dating using 1 4 ev infrared excitation for determining the time of deposition or compaction of organic rich sediments and peat is assessed with measurements on seven samples from six different lithostratigraphic units one is of zero age two have associated 14c ages three are known to have been deposited during an interglaciation and one is 1 ma old the samples yield satisfactory optical ages ranging from 0 to over 100 ka we conclude that the muir point formation southern vancouver island and the whidbey formation northwestern washington state were both deposited during 18o stage 5 as previously deduced from other evidence the age obtained from the 1 ma sample was significantly too low the optical dating method is simpler and more precise than thermoluminescence dating and is recommended for future work

a review and comparison of fracture mineral investigations and their application to radioactive waste disposal abstract a compilation and comparison of fracture mineral studies from the canadian and fennoscandian shields and the french massif central shows many similarities indicating larger external control over fracture mineral deposition with different rock types exerting local controls the sites investigated represent a wide range of geological settings and host rock types ranging from felsic intrusive and extrusives to ultramafic intrusives and volcanics that span an age range from 2 5 to 0 36 ga typical fracture minerals found at canadian shield sites include calcite quartz chlorite and clays and these do not appear to be dependant on age erosional depth or geological environment the fennoscandian shield has a much larger variety of fracture filling minerals with epidote zeolites prehnite fluorite pyrrhotite fe oxides serpentine graphite magnesite and barite in addition to the minerals typically found at canadian shield sites the major control on fracture mineral type is most likely variations in rock type and fluid chemistry and temperature the c and o isotopic range of calcite is very similar among sites late stage hydrothermal calcite with strongly depleted 18o values is common at many sites all of the sites have calcite with 18o isotopic values in the range of 5 to 20 pdb indicative of formation from meteoric water or basinal brines that have undergone varying degrees of water rock interaction one canadian and a few swedish sites have calcite in the shallower portion of the rock that shows isotopic evidence of dissolution and re precipitation in equilibrium with the present day waters there are some striking similarities in fluid inclusion data among sites most sites have an elevated temperature 100 300 c low salinity group of fluid inclusions within the nacl h2o system and a lower temperature 50 150 c higher salinity group of fluid inclusions within the nacl cacl2 h2o system fluid inclusion density plots show some evidence of simple cooling but most sites show two or more fluids were responsible for calcite formation the origin of most of these fluids was magmatic hydrothermal or meteoric water that had undergone varying degrees of water rock interaction but basinal brines and seawater were also possible sources several techniques and methods have been used to further characterize calcites strontium isotopes and rare earth elements can be useful to recognize different families of calcite uranium th dating has found many old calcites beyond the useful range of the technique but also some relatively young calcites that may be related to interglacial periods where fluid inclusion data exists formation temperatures were not consistent with a glacial water origin crush and leach experiments with ion and gas chromatography and thermal ion mass spectrometry have characterized inclusion fluids but special care must be used to ensure only one generation is sampled at a time cathodoluminescence and scanning electron microscopy with energy dispersive spectrometry has been useful in identifying multiple fluid generations within single calcite samples laser ablation and raman spectrometry are additional techniques that are useful in determining individual fluid inclusion chemistry and isotopes

applications of land based high resolution seismic reflection analysis to quaternary and geomorphic research abstract the availability in the last few years of low cost microcomputers and multichannel seismographs has made possible the application of high resolution digital seismic reflection profiling to quaternary problems seismic analysis of the subsurface can provide continuous two dimensional sections containing detailed structural and stratigraphic information a review of the general principles of shallow seismic reflection methods includes the nature of seismic sources the use of shotgun shells the application of the optimum offset method data processing and the issue of site dependency a brief overview is provided of seismic and sequence stratigraphy four case studies illustrate the application of reflection seismic profiling 1 champlain sea sediments late wisconsinan on the flank of the gatineau hills near quyon quebec 2 the definition of bedrock valleys beneath pleistocene deposits near shawville quebec 3 the fill of a linear depositional basin okanagan valley british columbia 4 the seismic signatures of topset and foreset beds slope failures and a distributary channel of the fraser river delta british columbia

the stability of fine grained sediments from the fraser river delta the stability and erodibility of benthic fine grained sediments on the foreshore and upper foreslope of the fraser river delta were measured using thein situbenthic flume sea carousel the erosion threshold c 0 which varied between 0 11 and 0 50 pa was inversely related to erosion rate it was also proportional to sediment wet bulk density b in the form c 0 7 10 4 b 0 47 this trend agreed with those obtained from four other sites across canada that encompassed a wide range in sediment densities 1000 b 2000 kg m 3 erosion threshold shields parameter c was positively related to grain reynolds number over the silt clay size range 0 01 re 5 c 2 86re0 58 this was similar to earlier findings for water saturated sediment this trend is also in continuity with published threshold values measured in biostabilized sand 5 re 50 copyright 1997 academic press limited three erosion types were observed type ia erosion was a surface phenomenon caused by the presence of a thin organic fluff layer it occurred at current speeds less than 0 3 m s 1 type 1b erosion asymptotically decaying with time characterized the mid portions of each erosion time series and occurred at current speeds of 0 3 0 9 m s 1 type i ii erosion transitional was largely found on the foreslope and occurred at current speeds in excess of 0 8 m s 1 the erosion process began in all cases under turbulent transitional flows the change from type i to type ii erosion corresponded to the onset of turbulent rough flows 60 re 70 this is supported by video observations which showed type i erosion to be largely the result of entrainment of small aggregates and flocs whereas type ii erosion was the result of enlargement of surface irregularities and subsequent undercutting and release of large aggregates mean erosion rate em was independent of either azimuthal current speed or bed shear stress it was largely constant throughout each deployment and varied between 1 4 and 7 4 10 4 kg m 2 s 1

biosedimentological zonation of boundary bay tidal flats fraser river delta british columbia boundary bay tidal flats on the inactive southern flank of the fraser delta have surface sediments consisting almost entirely of very fine to fine well to very well sorted sands which show a gradual fining shorewards trend five floral sedimentological zones form distinct biofacies these are from the shoreline seaward the saltmarsh algal mat upper sand wave eelgrass and lower sand wave zones the lower limit of the saltmarsh lies at a constant level above which the maximum duration of continuous exposure rises abruptly from 12 to 40 days similarly at the lower limit of the algal mat zone the maximum duration of continuous exposure jumps from 1 to 2 days and at the upper limit of the eelgrass zone from 0 5 to 0 8 days these correlations between exposure and zonation are suggested to be causal in the algal mat and eelgrass zones microtopography of biogenic origin only a few centimetres high creates lateral heterogeneity within the zonal biofacies in the upper sand wave zone very low amplitude a 0 1 m symmetrical sand waves 30 m of probable storm wave origin have a similar effect in the lower sand wave zone sand waves a 0 5 m 60 m are formed by tidal currents or wave action and physical sedimentary structures dominate over biogenic ones the densities of the following macrofaunal organisms which produce distinctive biogenic sedimentary structures were determined on two surveyed transects callianassa californiensis and upogebia pugettensis both thalassinidean shrimps three polychaete worms abarenicola sp spio sp and clymenella sp the bivalve mya arenaria and the gastropods batillaria attramentaria and nassarius mendicus callianassa excavate unlined temporary feeding burrows whereas upogebia build mud lined permanent dwelling burrows upogebia are restricted to below mean sea level where continuous exposure is 0 5 days whereas callianassa extend up to a level just below mean higher high water where maximum continuous exposure rises abruptly from 4 to 9 days this difference in range is probably due to the latter s greater anoxia tolerance a necessary adaptation for life in an unlined feeding burrow

pleistocene glacimarine sedimentation on the continental slope off vancouver island british columbia abstract cordilleran ice sheet activity has had a significant influence on glacimarine sediment transport and deposition on the western canadian continental slope resulting in distinct sediment facies here we present lithogenic sediment grain size distributions grains 250 m g 1 63 m 10 to 60 m and 2 to 4 m and mass accumulation rates mar from a marine core md02 2496 collected 50 km offshore of vancouver island british columbia the lithogenic fraction of sediment deposited on the slope increased as grain size decreased and sediment sorting increased at 30 ka when the cordilleran ice sheet grew into southern british columbia during the fraser glaciation as the ice sheet advanced onto the continental shelf near core md02 2496 between 19 and 17 ka the proximal ice margin dramatically increased lithogenic sediment mars glacimarine sedimentation at this time was associated with cyclic deposition of generally coarse poorly sorted sediment an 80 year cyclicity suggests the influence of 1 outburst floods 2 lunar or 3 solar cycles on tidewater outlet glacier discharge rapid ice sheet retreat at 17 ka is indicated by ice rafted debris ird deposition followed by the deposition of fine well sorted silt suggestive of iceberg discharge followed by rock flour in a meltwater plume lithogenic sediment mars decreased dramatically at the bolling with a brief return to coarse poorly sorted sediments during the younger dryas glacimarine sedimentation decreased by 10 ka as the cordilleran ice sheet extent diminished to the areal extent of modern ice fields

seismogenic zone temperatures and heat flow anomalies in the to nankai margin segment based on temperature data from iodp expedition 333 and thermal model the location of the seismogenic zone across the to nankai margin segment has been widely investigated using geodetic tsunami seismologic and heat flow data as well as thermal models seafloor heat flow measurements show large scatter raising questions about the thermal state of the incoming and overriding plates in this study new temperature and conductivity measurements recorded in the philippine sea plate psp and in the accretionary prism during iodp expedition 333 are integrated with recent data on the margin structure and seismicity to improve constraints on the thermal structure of the incoming plate and the subduction zone as well as the thermal conditions within the seismogenic zone iodp expedition 333 measurements provide heat flow values that are lower than the average of nearby seafloor measurements thermal modeling for the psp suggests that hydrothermal warming is insignificant in the trench thus an observed widespread positive thermal anomaly in the shikoku basin that peaks at the kashinozaki knoll more likely results from vigorous thermal convection in the upper mantle in back arc context the modeled thermal structure of the margin from the trench to the mantle shows a significantly colder interplate contact than in previous studies the seismogenic zone is likely to be 30 170 km from the deformation front corresponding to the 100 340 c temperature range the 1944 co seismic slip zone extends farther southward where temperatures are about 60 c slow slip earthquakes are located in the downdip transition zone between 340 and 440 c across the intersection of the moho and the megathrust fault this improved thermal structure from the trench to the mantle results mainly from a better estimate of oceanic plate age slab dip and sedimentation rate variations in the trench this last parameter cools the interplate contact until a depth of 35 km shifting the thermally defined seismogenic zone landward by 20 km and significantly diminishing its influence near the corner flow area

cold climate peat formation in canada and its relevance to lower permian coal measures of australia abstract canada is a vast cold country large expanses of wetlands occur whose characters change predictably over continental distances along north south temperature gradients and coastal inland precipitation trends the changing climatic conditions during the holocene have influenced the initiation and rates of peat formation for instance most of the peats of south central canada are not older than 5000 years b p those in the arctic regions are fossil deposits of the hypsithermal times of 7 8000 years b p maintained at the surface because of the low rates of peat oxidation an analysis of the environments of formation and of the stratigraphy of recent peats which formed under cold to cold temperate climate in canada forms the basis for a comparative study and a better understanding of the permo carboniferous coals of gondwanaland brazil south africa and australia much of the stratigraphic complexities that occur in the peat sequences are blurred out during organic decomposition and metamorphism leading to coal formation however some of the major features of the sequences that develop in string fens from basal sedge peats up to sedge woody peats and in boreal and cold temperate bogs and swamps from basal lacustrine deposits with some reworked and algal rich sediments grading upward into sedge peats to sphagnum sedge peat to sphagnum woody or just woody peats may be recognizable in banded coal seams it is suggested that future detailed comparative microfacies analyses of the cold peat sequences of canada and the lower permian coal seams of australia will allow better reconstructions and understanding of ancient wetlands without exclusively using the less appropriate albeit better known recent models of subtropical swamps

liquefaction features on the fraser delta evidence for prehistoric earthquakes sand dykes and sills and vented sand boils on the fraser river delta and adjacent serpentine river floodplain in southwestern british columbia record one or more major liquefaction events the source of the dykes is a shallow subsurface saturated sand unit that was deposited in foreslope and distributary channel environments during holocene progradation of the fraser delta the dykes cut steeply through a crust of delta topset muds and locally flatten out as sills in overlying peaty sediments at two sites evidence was found for venting of sand onto a subaerial or intertidal surface liquefaction and upward movement of sand and water locally deformed the intruded sediments causing some subsidence and uplift of the delta surface all observed liquefaction features are younger than ca 3500 bp and at least some are younger than 2400 bp it is not clear however whether they formed during one or several separate events a review of possible causes suggests that the liquefaction features probably are seis

seismic investigation of the coast plutonic complex insular belt boundary beneath the strait of georgia the strait of georgia a topographic depression between vancouver island and the mainland of british columbia is considered to be the boundary between two tectonic provinces the coast plutonic complex on the east and the insular belt to the west the allochthonous nature of the insular belt has been established mainly on the basis of paleomagnetic measurements various tectonic models to explain the geological differences between the two provinces have been proposed one of these suggests that the boundary is an old transform fault zone and is represented currently by a thrust fault along the eastern side of the strait of georgia other models propose that the coast plutonic complex is a feature superimposed by tectonic and metamorphic events after the accretion of the insular belt such models do not require a major crustal discontinuity along the strait of georgia in may 1982 a seismic refraction survey using a 32 l air gun and a radio telemetering sonobuoy system was carried out in the strait of ge

fluid evolution in fracturing black shales appalachian basin opening mode veins in cores drilled from the mudrocks overlying and underlying the major silurian salt decollement in the appalachian plateau tioga and lawrence counties pennsylvania have mineralogic and isotopic compositions generally matching those of their host mudrocks suggesting opening and filling amid little cross stratal fluid motion calcite and most trace minerals probably entered the veins via dissolution reprecipitation from nearby host rock consistent with this interpretation are the observations that 1 trace minerals within the veins including quartz pyrite and dolomite are invariably also present within the layers hosting the veins with vein cement minerals generally reflecting the abundance and solubility of minerals in the host rock and 2 carbon and oxygen isotopic compositions of vein filling calcite are similar to those of calcite within the host rock with vein filling 18o slightly depleted and 13c slightly enriched modeling the fluid isotopic evolution assuming vein opening and filling amid immobile connate formation water accounts for these minor but systematic differences which are attributable to increasing temperature and hydrocarbon maturation an exception to the above trend is barite which despite its low solubility is systematically enriched in veins with respect to the host rock it is unclear whether barite precipitation resulted from the influx of external fluids perhaps deriving from silurian salt or from barium mobilized at depth from local clays or organic material

the paraglacial geomorphology of the fraser lowland southwest british columbia and northwest washington abstract the fraser lowland is interpreted as a complex paraglacial landsystem in the sense that all its landform units landform and sediment associations and thus the whole landsystem have been modified by nonglacial processes conditioned by glaciation the late pleistocene and holocene processes of modification include slope erosion glacimarine marine glacifluvial fluvial glacilacustrine lacustrine organic mass movement and aeolian this complex paraglacial landsystem has transitioned from proglacial through marine to its present dominantly fluvial character landforms representative of each sediment redistribution process are described and a conceptual model is developed with relative sea level and sediment source changes as the primary drivers the sediment wave and sediment exhaustion models are compared and illustrated in the context of this paraglacial land system anthropogenic modification during the past century the anthropocene has complicated the paraglacial story and is shown to impact the incidence of natural hazards especially in the context of hydroclimate change

palynology of holocene top set aggradational sediments of the fraser river delta british columbia abstract palynological study of radiocarbon aged top set holocene sediments of the fraser delta british columbia reveals a record of tidal marsh river marsh and river swamp environments which indicate former sea level positions and rates of sea level change interbedded silts and fine sands containing pinus and cyperaceae pollen and monolete fern spores occur between 15 1 and 14 2 m depth and are interpreted as freshwater dominated delta front marsh deposits organic rich silts containing grass and skunk cabbage pollen and horsetail spores between 14 2 7 8 m depth represent an emergent delta top marsh environment regularly flooded by the fraser river arboreal pollen types pine spruce and alder dominate organic rich silts between 7 8 and 5 8 m but rosaceae pollen rises to dominance in peatier sediments between 4 7 5 8 m these two zones record natural vegetation succession from marsh to swamp due to increased relative elevation of the site an increase in arboreal pollen in organic rich silts between 4 7 and 2 3 m signals a drop in relative elevation and return to regular flooding declines in percentages of arboreal pollen and increases in rosaceae and skunk cabbage pollen indicate preliminary stages of bog development and disappearance of fluvial influence above 2 3 m organic rich silts formed mainly in a fluvially dominated marsh setting as top set aggradation kept pace with sea level rise between approximately 7960 and 4410 yr b p an apparent slowing or cessation in sea level rise allowed peaty sediments to form around 6000 yr b p the rate of sea level rise again declined at 4410 yr b p causing organic rich silts to be replaced by peat deposition the study provides insights into the history of sea level change and aggradation in the fraser river delta

assessing the past thermal and chemical history of fluids in crystalline rock by combining fluid inclusion and isotopic investigations of fracture calcite abstract fluid inclusion studies combined with the isotope geochemistry of several generations of fracture calcite from the olkiluoto research site finland has been used to better understand the past thermal and fluid history in the crystalline rock environment typically fracture mineral investigations use o and c isotopes from calcite and an estimate of the isotopic composition of the water that precipitated the calcite to perform 18 o geothermometry calculations to estimate past temperature conditions by combining fluid inclusion information with calcite isotopes one can directly measure the temperature at which the calcite formed and can better determine past fluid compositions isotopic petrologic and fluid inclusion studies at the olkiluoto research site in finland were undertaken as part of an investigation within the finnish nuclear waste disposal program the study revealed that four fluids were recorded by fracture calcites from petrologic evidence the first fluid precipitated crystalline calcite at 151 225 c with a 13 c signature of 21 to 13 9 pdb and a 18 o signature of 12 3 13 0 smow these closed fracture fillings were found at depths greater than 500 m and were formed from a high temperature low salinity na cl fluid of possible meteoric water altered by exchange with wallrock or dilute basinal origin the next fluid precipitated crystalline calcite with clay at 92 210 c with a 13 c signature of 2 6 to 3 8 pdb and a 18 o signature of 19 4 20 7 smow these closed fracture fillings were found at depths less than 500 m and were formed from a moderate to high temperature low to moderate salinity na cl fluid likely of magmatic origin the last group of calcites to form record the presence of two distinct fluid types the platy a calcite formed at 95 238 c with a 13 c signature of 12 2 to 3 8 pdb and a 18 o signature of 14 9 19 6 smow from a high temperature low salinity na cl fluid of possible magmatic origin the platy b calcite formed at 67 98 c with a 13 c signature of 13 0 to 6 2 pdb and a 18 o signature of 15 1 20 1 smow from a low temperature high salinity ca na cl fluid of possible basinal brine origin the two calcites are related through a mixing between the two end members the source of the fluids for the platy grey a calcites could be the olivine diabase dykes and sills that cut through the site the source of fluids for the platy b calcites could be the jotnian arkosic sandstone formations in the northern part of the site at the olkiluoto site 18 o geothermometry does not agree with fluid inclusion data the original source of the water that forms the calcite has the largest effect on the isotopic signature of the calcites formed large isotopic shifts are seen in any water by mineral precipitation during cooling under rock water equilibrium fractionation conditions different calcite isotopic signatures are produced depending on whether cooling occurred in an open or closed system water rock interaction at varying w r ratios between a water and a host rock can explain the isotopic shifts in many of the calcites observed in some cases it is possible to shift the 18 o of the water by 11 5 smow using a realistic water rock ratio this process still does not explain some of the very positive 18 o values calculated using fluid inclusion data several other processes such as low temperature recrystallization boiling kinetic effects and dissolution of calcite from fluid inclusion walls can affect isotopic signatures to varying degrees the discrepancy between fluid inclusion data and 18 o geothermometry at the olkiluoto site was most likely due to poor constraint on the original source of the water

stability of the fraser river delta front the distributary front deposits of the delta consist mainly of interlayered sand and silt and lie in one of the most seismically active zones in canada subsurface deposits at the north tend to be siltier than those at the south sediments on the surface of the delta slope range from clayey silts at the north to pure sands at the south slope angles vary from 23 at the head of the slope to 1 2 within 2 km beyond the tidal flats hydraulic bedforms observed on the sandy slopes southeast of the main channel gradually increase in size from small ripples to large asymmetric sand waves 2 3 m high and approximately 30 m long they are generated primarily by flood tidal currents which scour the seabed to a water depth in excess of 100 m formation of gullies which crease the delta slope probably is initiated principally by failure of oversteepened deposits at a channel mouth previous studies have suggested that the large hummocks or ridges at the base of the slope off the main channel have been formed by the co

asymmetry in holocene river deltas patterns controls and stratigraphic effects abstract understanding controls on sediment distribution in river deltas is paramount to predicting facies relationships and stratal architecture most classifications of deltas have focused on subaerial plan morphology as a simplistic function of river tide and wave energy new work however is revealing the importance of subaqueous deposits and in particular shore parallel sediment redistribution in the shaping of delta planform delta asymmetry has emerged as an important characteristic reflective of patterns of alongshore sediment dispersal asymmetry has been described from onshore and offshore environments from several different types of modern deltas but aspects of asymmetry have not been fully documented and the degree to which these patterns are recorded in deltaic strata is not yet known this study is a comprehensive literature review of sediment distributions in modern deltas focusing on studies with high resolution geomorphic geophysical and geochronological datasets we reviewed 27 deltas using over 100 papers primarily from the past 15 20 years morphological facies and stratigraphic aspects were analyzed across the entire spectrum of deposits from the delta apex to the most distal muds of the prodelta we define quantifiable indices of asymmetry describing upcurrent vs downcurrent distribution of sediment volume sediment area sediment caliber and distributary channels most deltas are asymmetrical to some degree with respect to one or more of these parameters many deltas are increasingly skewed toward the downcurrent side from proximal to distal sub environments i e delta plain delta front prodelta some deltas are skewed toward the upcurrent side in one sub environment and toward the downcurrent side in another sub environment sand is preferentially deposited on the downcurrent side of most deltas but distributary channels tend to develop toward the upcurrent side the highest sand mud ratios are often on the upcurrent side in the lower delta plain but in the delta front these ratios are highest on the downcurrent side these complex patterns of asymmetry reflect different combinations of controls including discharge partitioning lobe abandonment and localized transgression plume deflection by coastal currents dominance of longshore current direction variable subsidence and other factors these processes may result in upcurrent downcurrent variations in clinoform geometry rates of progradation and stratal lapping relationships asymmetry has multiple aspects manifestations and controls even within a single delta but the long term preservation potential of these patterns likely varies depending on depositional setting and shoreline trajectory studies of ancient deltas will be better informed by recognizing the wide variety of controls on sediment distribution and avoiding the tendency toward a single model of delta asymmetry

melting behavior of fluid inclusions in laboratory grown halite crystals in the systems naclh2o naclkclh2o naclmgcl2h2o and naclcacl2h2o abstract the chemical composition of aqueous fluid inclusions in crystals of halite can be accurately determined from observed melting behaviors of ice hydrohalite and sylvite some fluid inclusion melting behaviors observed in laboratory grown halite crystals systems nacl h 2 o nacl kcl h 2 o nacl mgcl 2 h 2 o and nacl cacl 2 h 2 o differ from predicted stable equilibrium relations in the nacl h 2 o and nacl kcl h 2 o systems observed first melt temperatures are up to 15 c below the equilibrium eutectic temperatures of 21 2 and 22 9 c respectively the final melting temperature of ice in the presence of hydrohalite and the final melting temperature of hydrohalite are reproducible and match predicted melting temperatures the limit of detection of sylvite daughter crystals in the nacl kcl h 2 o system is approximately 5 wt 1 molal kcl final melting temperatures of sylvite match published equilibrium data to within 0 3 c in the nacl kcl h 2 o system at halite saturation m kcl can be determined from the final sylvite dissolution temperature or from the final melting temperature of hydrohalite fluid inclusions in the nacl mgcl 2 h 2 o and nacl cacl 2 h 2 o systems that form stable salt hydrates mgcl 2 12h 2 o and cacl 2 6h 2 o during freezing first melt within 3 c of predicted eutectic temperatures 37 and 52 c however fluid inclusions with mgcl 2 or cacl 2 may also start melting at temperatures as low as 80 c such low first melt temperatures indicate the presence of metastable salt hydrates presumably mgcl 2 8h 2 o mgcl 2 6h 2 o or cacl 2 4h 2 o the formation of metastable phases during freezing of fluid inclusions can lead to misinterpretation of the chemical composition of fluid inclusions in natural samples this is especially true for fluid inclusions with first melt temperatures below 37 c which may be erroneously interpreted as being rich in cacl 2 the final melting of ice in the presence of hydrohalite may vary by more than 15 c in fluid inclusions of different size but identical bulk composition and occurs at lower temperatures than predicted in fluid inclusions from the nacl mgcl 2 h 2 o and nacl cacl 2 h 2 o systems however the final melting temperature of ice in inclusions which fail to nucleate hydrohalite and the final melting temperature of hydrohalite are reproducible to within 0 1 c and can be used to determine mgcl 2 and cacl 2 molalities

origins closed system formation and preservation of calcites in glaciated crystalline bedrock evidence from the palmottu natural analogue site finland abstract a study of the geochemistry of fracture filling calcite from the palmottu research site a u th deposit located about 100 km nw of helsinki finland was part of a comprehensive natural analogue research project considering the migration of u in the crystalline bedrock environment fracture filling minerals act as records of the paleohydrological and chemical conditions and therefore provide insight into magmatic processes ore deposits and long term stability of the crystalline bedrock environment in relation to deep disposal of radioactive waste an earlier investigation of calcite and associated u minerals identified a recent origin for these fracture infillings uranium series disequilibrium data indicated that relatively recent glacial water had penetrated to a depth of 62 m a fluid inclusion study combined with the isotope geochemistry of several generations of fracture calcite was undertaken to further study this aspect and to better understand the thermal and fluid history in the crystalline rock environment in general the study revealed that at least 3 fluids were recorded by fracture calcites 1 a crystalline calcite precipitated at 139 238 c from a low salinity na cl fluid of magmatic or metamorphic origin 2 a massive calcite with high salinity fluid inclusions precipitated at 136 141 c from a high salinity ca na cl fluid of magmatic or metamorphic origin and 3 a massive calcite with low salinity fluid inclusions precipitated at 43 286 c from a low salinity na cl fluid of magmatic or metamorphic origin that underwent equilibrium fractionation during cooling in a rock dominated system the preservation of high temperature infillings and the cooling trend indicating isotopic re equilibration of water due to a very low water rock ratio demonstrate that the downward percolation of geologically recent waters is limited despite the reworking of highly soluble u compounds in the upper tens of metres of the bedrock that was shown by u series disequilibrium studies the veins in which these calcites occur have not experienced a later phase of fluid activity that dissolved or altered the calcites therefore it is likely that they have not been reactivated as transmissive fractures since that initial hydrothermal episode even during the quaternary history in which the formation was subjected to ice sheet loading and unloading

postglacial deltaic sediments southern fraser river delta british columbia the fraser river delta the largest delta on the west coast of canada has been built into the strait of georgia during the holocene drill hole and seismic reflection records reveal a succession of sedimentary units deposited during early holocene progradation of the delta these overlie an irregular surface developed on pleistocene drift mud and silt similar to sediments presently accumulating off the mouth of fraser river in the southern strait of georgia are conformably overlain by a thick unit of sandy foreset beds dipping gently to the south southwest into boundary bay and deposited in a foreslope environment the foreset unit is sharply overlain by a much thinner topset sequence comprising silt and sand deposited in intertidal fluvial channel and overbank environments and peat deposited in swamps and bogs fifteen accelerator mass spectrometry radiocarbon dates on shell and wood indicate that most of the deltaic sediments south of the main channel of fraser river were deposited between ca 7

aquifer heterogeneity from sh wave seismic impedance inversion we collected sh wave seismic reflection data over a shallow aquifer in southwestern british columbia to investigate the use of such data in hydrogeologic applications we used this data set in developing a methodology that uses cone penetrometer data as an integral part of the inversion and interpretation of the seismic data a bayesian inversion technique converts the seismic amplitude variations to velocity variations honoring the probabilities of the priors and adhering to a geologically reasonable sparseness criterion velocity measurements acquired with the cone penetrometer provide velocity profiles and vertical seismic profiling vsp data all of which are valuable in properly constraining the bayesian inversion the differentiation of lithologies in this data set sand and clay is accomplished by first using a normalization procedure to remove the impact of effective stress which dominates the velocity variation in the upper 10 to 20 m the final transformation of seismic velocities to void ratio for the sand dominated regions is made using laboratory derived measurements it provides an image of the heterogeneity of the near surface aquifer