a methodology for the study of the relation between coastal cliff erosion and the mechanical strength of soils and rock masses abstract a methodology is proposed to make approximate estimates of the destructive force of waves at the bottoms of cliffs where no accurate bathymetric data are available by means of correlation between the erosion rate of rocky coasts and the mechanical strength of soils and rock masses the correlation used makes it possible to obtain a linear semi logarithmic expression between the long term average erosion rate from an engineering standpoint of coasts consisting of different lithologies wave energy and the uniaxial compressive strength of soils and rock masses forming the cliffs the uniaxial compressive strength of soils consisting of landslide debris was measured using a pocket penetrometer and the rock mass index rmi method was used for rock masses these methods were chosen after critical analysis of the methodologies currently available the proposed approach was tested in the cilento area of southern italy and in particular along a 6 km stretch of coast typified by rock masses and landslide debris that are particularly susceptible to erosion this coastline is exposed to south westerly waves which in deep water reach significant heights between 1 and 3 m and significant wave periods between 4 and 7 s estimates of the coastal erosion rates were made by studying the variations especially in restricted headland areas occurring over two time spans 30 and 45 years respectively by comparing topographic maps and aerial photographs taken at different times these comparisons give approximate indications of retreats of 15 m over the time span of 30 years average erosion rate of 0 5 m year 1 and of 35 m over the time span of 45 years average erosion rate of ca 0 8 m year 1 these data do have a local significance but clearly show how quick these processes sometimes are lastly the study of a notch incised by wave action on a concrete sea wall built to protect a terrace made it possible to quantify the impact of erosion on concrete it was possible to obtain rmi values through field observations furthermore it was possible to obtain the constants of the hoek and brown failure criterion using rmi on the basis of rmi values the rock masses studied were defined as moderately strong to strong and according to the hoek and brown criterion as poor to fair a semilogarithmic linear relation was found between the strength of landslide debris rock masses and concrete as well as their respective long term erosion consequently a rough estimate of the destructive force of waves ca 24 mpa was calculated this value is given by the product of the mean value of their hydraulic pressure for a non dimensional constant which in turn takes into account the sandy pebbly beach sediment at the foot of the cliffs that acts as an abrasive on the rock mass

estimating long term cliff recession rates from shore platform widths coastal cliff erosion is a problem in many coastal areas however often only very limited data are available to quantify the rates of recession for the development of coastal management strategies in the soft flysch deposits of the waitemata group auckland new zealand coastal cliffs are associated with shore platforms two models exist for the profile evolution of shore platforms and associated cliffs the first suggests that an equilibrium profile develops in response to erosive processes and this profile subsequently migrates landward the second model suggests that the seaward margin of the shore platform is relatively static and the profile extends landward through a combination of cliff recession and platform lowering physical simulations and field measurements for mudstone and limestone lithologies indicate that the second model is more likely for soft flysch deposits a eustatic sea level curve for the weiti estuary auckland suggests that up to 7120f70 years have been available for shore platform development since sea level reached the present seaward margins of shore platforms shore platform widths were measured using gps at two sites in waitemata group rocks the north shore of auckland and the southern side of the tawharanui peninsula north auckland the long term cliff recession rates estimated from shore platform widths 1 4f0 1 to 14 3f0 1 mm y 1 are consistent with the lower end of the average range of cliff top and face recession rates published for waitemata group rocks using different methods 11 75 mm y 1 and in agreement with cliff base recession estimates 3 5 mm y 1 shore platform widths were qualitatively related to the rock mass characteristics of the associated cliffs and therefore platform widths could provide a method of identifying regions of potential hazard d 2005 elsevier b v all rights reserved

hydrogeochemical characterization of oilfield waters from southeast maracaibo basin venezuela diagenetic effects on chemical and isotopic composition free water and water in emulsion with oil from hydrocarbon wells onshore offshore lake maracaibo were extracted and analyzed the use of classical and new chemical diagrams evidenced that na hco3 and na cl are the main chemical facies whereas na so4 facies was rare and revealed only in faulted areas in which shallow groundwater was involved in deep circulation cretaceous ca cl waters were not revealed but their imprint on some samples was traced and evidenced by langelier ludwig brine differentiation and caexcess vs nadeficit diagrams these square plots allowing a discrimination between the water contributions from the different source rocks should be more exploited as hydrogeochemical tools in hydrocarbon exploration original data on monocarboxylic anions showed acetate concentration higher than ten times that of formate at sampling conditions but speciation under deep conditions indicated a reversed activity dominance calculation of saturation indexes and kinetic modeling showed an active precipitation of chalcedony kaolinite and clays especially where the temperature was lower t 100 c formation waters and lake water showed quite similar chloride concentration and hydrogen isotope composition however thermodynamic calculations at the oilfield p t conditions revealed chlorite and illite produced during previous diagenetic stages of misoa sandstones recrystallization to smectite and vermiculite in present day stage the diagenetic water produced in these reactions could have enriched the 18o isotopic composition of approximately 2 this isotope diagenetic effect was more evident in na hco3 waters which also showed a decrease in chloride at constant boron concentration as a consequence of clay dewatering in this regard a new boron geothermometer useful for formation waters is also proposed t c 5 1364 ln 1 b mg 1 5 728 0 180 0 164 0 012

a study of wintertime circulation anomalies during past el nino events using a high resolution general circulation model ii variability of the seasonal mean response in this paper the response of a relatively high resolution 11 layer general circulation model gcm to a number of different sea surface temperature s s t anomalies in the tropical east and west pacific is studied the integrations were all run for 540 days in a perpetual january mode and had either mean or envelope orography the s s t anomalies included an enhanced composite el nino anomaly the observed anomalies during december 1982 and december february 1982 3 and a weak 1 k positive s s t anomaly in the tropical west pacific the objective of this study is to assess whether the observed variability in wintertime circulation anomalies between past el nino events can be modelled by considering the 90 day mean interannual variability of the integration with the composite el nino s s t anomaly it is concluded that such observed variability cannot be modelled in this way and that variations in tropical pacific s s t anomaly from one event to another are crucial in accounting for observed extratropical variability over the pacific and north america in particular it is shown that the model s response to the 1982 3 anomaly and the weak west pacific anomaly are significantly different from the response to the composite el nino anomaly over the pacific and north america and agree well with the appropriate observations for 1982 3 and 1976 7 respectively it is also concluded that the relatively weak extratropical response during the winter of 1972 3 was related to the fact the s s t anomalies were confined to the east pacific by contrast the response to the weak west pacific anomaly was very strong and statistically significant over the pacific and north america

mass transfer and problems of secondary porosity creation in deeply buried hydrocarbon reservoirs abstract secondary porosity created by the post depositional leaching of detrital grains and cements can be of great economic importance the term secondary porosity is only descriptive and does not give any information on whether the porosity of the rock has been enhanced in reality there are two end member volumetric outcomes to the leaching process firstly the mineral can be completely dissolved and its components transported out of the system in such an instance the porosity of the rock will be enhanced secondly it is possible that a mineral will decompose and by product minerals will be precipitated which will occupy approximately the same volume as the original mineral the latter case is more likely where the pore waters are close to equilibrium with the majority of the minerals of the rock this will occur at elevated temperatures and or where the pore waters have been in contact with the rock for a long time these conditions are commonly met during intermediate to deep burial many metastable minerals such as high temperature feldspars probably decompose in this way a consequence of the decomposition of such metastable minerals is that primary porosity will be swapped for secondary and that older and more deeply buried rocks will contain a higher proportion of secondary porosity the mass transport equation may be used to examine the physico chemical environment where enhanced porosities most likely occur during leaching by using a simple non equilibrium mass transport model based on the silica system it is possible to demonstrate the relative importance of flow rate reaction rates specific surfaces and temperature in controlling the areal extent of leaching wide leaching zones are related to high flow rates which in turn promote a high throughput of undersaturated fluid and dispersion leaching over a wide area is also favoured by low reaction rates which will occur at low temperatures although it is true to say that less of a given silicate mineral can be dissolved by an undersaturated pore water at low temperature than at high temperature it is probable that pore fluids from deeply buried sediments are more likely to be close to equilibrium with a given mineral than for instance meteoric water thus the most likely environment for the production of widespread enhanced porosity is in the shallow subsurface the lower flow rates and higher temperatures that are encountered during deep burial diagenesis will result in far narrower more intense leaching zones as a result providing sufficient reactive mineral is present any undersaturated pore water will approach equilibrium in a short distance in order to transport undersaturated pore waters appreciable distances in the deep subsurface it is necessary to minimize their interaction with the host rock this could occur if the pore fluid were to move through a fracture system where it would interact with a far smaller surface area of reactive mineral than if it moved through the pore network

water rock interaction and reactive transport modeling using elemental mass balance approach i the methodology water rock interaction and reactive transport modeling is an important tool for deciphering chemical and physical reactions occurring in sediments and rocks the modeling methodology calls for solving conservation equations to account for the interaction between mass transfer and reaction processes using a sequential iteration numerical method the formalism presented here improves upon the traditional approach by reformulating conservation equations to express chemical elemental mass evolution the elemental conservation equations describe mass change through mass transfer and kinetic reactions of solids and solute solute interaction equilibrium reaction expressions the system of equations is solved using a sequential iteration method whereby globally discretized mass transfer coefficients of conservation equations are injected explicitly into the conservation equations and solved locally at each node the result is a mathematically simple approach that eliminates the traditionally required use of primary and secondary species classification the formalism also allows the use of solute specific diffusivities in addition the tight coupling between mass transfer and reactions achieved by the methodology also allows nonlinear self organization or pattern forming phenomena to be captured the methodology is demonstrated with simulations of 1 a diffusive reaction system involving patterned hematite nucleation and 2 a flow through system where co2 charged water interacts with formation water in a sandstone reservoir both are isothermal one dimensional simulations in the first example convergent diffusive infiltration of fe and o2 from two opposite ends produces patterned precipitates a natural analog of such phenomena is the occurrence of iron oxide concretions in navajo sandstones of utah and arizona the second example demonstrates the formation of a diffusive solute migration front ahead of advective effluent displacement and reaction fronts such phenomena are observed when large quantities of co2 are injected into geologic formations the early arrival of diffusive solute fronts at nearby monitoring wells are noted by decreasing water ph and raised alkalinity some time before the arrival of the effluent

interactions of synoptic and planetary waves scale dependent forcing of a gcm abstract in order to better understand planetary wave synoptic wave interactions in the atmosphere and to develop a tool for further studies the authors have applied a wavenumber dependent external forcing to a general circulation model gcm the forcing constrains various length scales of the gcm to be close to those in the evolving analyses of the european centre for medium range weather forecasts and the national centers for environmental prediction the forcing acts either on the planetary waves pw defined as zonal wavenumbers 0 5 the synoptic waves sw defined as zonal wavenumbers 6 20 the synoptic waves plus the zonal mean sw0 or the synoptic waves plus the zonal mean and wavenumber 1 sw01 the form of the forcing is a linear relaxation to the evolving analyses with a time constant of 8 h this forcing is applied only to the temperature and vorticity equations of the gcm which has a spectral truncation of t42 control integrations of length 30 days have been run starting on 15 dece

the role of synoptic waves in the formation and maintenance of the western hemisphere circulation pattern abstractprevious studies have demonstrated that the nao the leading mode of atmospheric low frequency variability over the north atlantic could be linked to northeast pacific climate variability via the downstream propagation of synoptic waves in those studies the nao and the northeast pacific climate variability are considered as two separate modes that explain the variance over the north atlantic sector and the east pacific north american sector respectively a newly identified low frequency atmospheric regime the western hemisphere wh circulation pattern provides a unique example of a mode of variability that accounts for variance over the whole north atlantic north american north pacific sector the role of synoptic waves in the formation and maintenance of the wh pattern is investigated using the ecmwf reanalysis datasets persistent wh events are characterized by the propagation of quasi stationary rossby waves across the north pacific north american north atlantic regions and by associated s

understanding and modelling extra tropical teleconnections with the indo pacific region during the northern winter teleconnections originated by anomalous heat sources over the tropical indo pacific oceans are investigated in this paper comparing observational results with numerical simulations run as part of the re forecast set for the latest ecmwf seasonal forecasting system system 4 we show that the traditional methodology of linearly relating circulation anomalies to sst anomalies while appropriate for signals originated in central and east pacific fails to adequately identify the response to anomalous heating over the west pacific and most of the indian ocean because of the relatively weak or even negative correlation between sst and rainfall anomalies in these regions instead if teleconnections are computed from covariances with rainfall anomalies a stronger consistency is found between observed and modelled patterns as well as between diagnostics derived from seasonal and intra seasonal time scales the main mode of inter annual variability in indo pacific rainfall associated with planetary scale teleconnections is a tri polar structure with two positively correlated centres in the western indian ocean and the central pacific and a third centre around the maritime continents which is anti correlated with the other two in the extratropical response positive rainfall anomalies over the western and central indian ocean wcio are connected with a negative height anomaly centred over alaska and a positive north atlantic oscillation nao signal in a way reminiscent of the cold ocean warm land pattern this teleconnection cannot be explained by the enso forced component of indian ocean rainfall and is in phase with signals associated with the madden julian oscillation results from the system 4 re forecasts show that the ecmwf coupled model reproduces the broad features of tropical and extratropical teleconnections with a good degree of fidelity however the model significantly over estimates the correlation between rainfall anomalies in the wcio with those over the western and central pacific the impact of this deficiency on the extratropical flow is to weaken the relationship between the nao and indian ocean rainfall on the seasonal scale and to affect the projection of the enso response on the nao finally we argue that reproducing the correct relationship between sst and rainfall anomalies in different part of the indo pacific basin is also crucial for the correct simulation of inter decadal variability particular care should be taken in interpreting results of agcm simulations with prescribed sst where the absence of feedbacks between convection and sst over the warm pool region affects the simulation of rainfall anomalies

unstable relationship between the pacific decadal oscillation and eastern china summer precipitation insights from the medieval climate anomaly and little ice age the eastern china summer precipitation is related to the pacific decadal oscillation pdo on interdecadal time scales in modern times but it remains unclear whether such a relationship holds prio

contribution of synoptic transients to the potential predictability of pna circulation anomalies el nino versus la nina abstractthe potential predictability pp of seasonal mean 200 hpa geopotential height z200 anomalies in the pacific north american pna region is examined for el nino and la nina separately by using 50 ensemble members of twentieth century agcm simulations observed sea surface temperature sst is prescribed for the period 1870 2009 and 14 el nino and la nina years after 1900 are selected for the present study the domain averaged value of pp for z200 in the pna region as measured by the signal to noise ratio for el nino is about 60 larger than that of la nina such a large pp is mainly due to a larger signal and partly to less noise during el nino compared to that during la nina the transient eddy feedback to the pna circulation anomalies is stronger during el nino events about 50 than that during la nina and this difference in the transients contributes significantly to the different z200 signals in the pna region the noise variance of the transients during el nino is about 17 smaller t

hydrothermal water rock interaction and the redistribution of li b and cl in the taupo volcanic zone new zealand abstract lithium b and cl occur as trace elements in the dominant protoliths rhyolite andesite and greywacke underlying high temperature hydrothermal systems in the taupo volcanic zone tvz the fluid mobility of li decreases substantially at 200 c 20 c with the pervasive deposition of quartz chlorite regardless of protolith and altering fluid compositions boron and cl are more fluid mobile than li at all temperatures with mobility affected by the rock type composition of circulating aqueous solutions and to a limited extent by incorporation of the trace elements in hydrothermal minerals uptake of b by clays decreases its mobility at 320 c occur compared to volcanic rocks the mobility of b and cl in greywackes is very low and thus the b cl signature of greywacke in hydrothermal aqueous solutions of the tvz is overwhelmed by the effects of rhyolite and andesite dissolution temperature dependent transitions from mg fe clays and phyllosilicates to k bearing illitic clays tend to decrease the mg li ratios in aqueous solutions at 200 c

decadal scale coastal cliff retreat in southern and central california abstract airborne lidar data collected in 1998 and 2009 2010 were used to measure coastal cliff erosion and retreat between the mexico california border and bodega head california cliff erosion was detected along 44 of the 595 km of shoreline evaluated while the remaining cliffs were relatively stable the mean cliff top retreat rate was 0 12 m yr while mean retreat averaged over the entire cliff face was 0 04 m yr the maximum cliff top and face retreat rates were 4 2 and 3 8 m yr respectively historical 1930s to 1998 and recent retreat rates were significantly inversely correlated for areas with large historical or recent cliff retreat such that locations with elevated historical retreat had low levels of recent retreat and locations with elevated recent retreat were preceded by low rates of historical retreat the strength of this inverse correlation increased with cliff change magnitudes up to r2 of 0 91 for cliff top retreat rates 2 9 m yr mean recent retreat rates were 52 83 lower than mean historical retreat rates although beaches can protect cliffs against wave driven erosion cliffs fronted by beaches retreated 49 more than cliffs without beaches on average unarmored cliff faces retreated 0 05 m yr between 1998 and 2009 2010 about three times faster than artificially armored cliffs alongshore metrics of wave cliff impact precipitation and cliff hardness were generally not well correlated with recent cliff changes a cliff hazard metric is used to detect cliff steepening and areas prone to future cliff top failures

hydrochemical water evolution in the aral sea basin part ii confined groundwater of the amu darya delta evolution from the headwaters to the delta and sio2 geothermometry summary we studied 40 artesian wells aws in the amu darya delta these wells include high salinity 52 g l and saline 5 24 g l waters but are mostly low salinity waters 1 3 2 9 g l the low salinity aws cluster into three types reflecting the variable mixing of different end member solutes residual brines and solutes deriving from silicate alteration dissolution of limestone and dissolution of gypsum the solutes are all undersaturated in calcite and gypsum contain a substantial cation excess against dissolved inorganic carbon and are characterised by low ca so4 ratios on the basis of the hydrochemical mass budgets of model cases we demonstrate that na rich cl brines 45 48 and a na2so4 brine 30 47 are the dominant solute components the solutes derived from aluminium silicate alteration are minor components 7 3 19 4 even less important are solutes from limestone or gypsum dissolution 0 05 3 7 these waters are unlikely to have originated from sediments hosting gypsum the low salinity aws must have acquired their dominant hydrochemical signatures under non equilibrium conditions between their remote unknown seepage areas and their discharge locations this acquisition may have begun during the early hydrochemical groundwater evolution when meteoric or surface water passed the critical zone under an arid climate regime warmer saline aws 40 c hosted in deeper cretaceous formations contain a high portion of nacl rich brine 85 and some are saturated in gypsum these waters were derived from fluids rising along faults from pre cretaceous strata the high salinity and relatively cold aws discharge close to the retreating aral sea south of its western basin these aws are suboxic and si concentrations are very low the aw hydrochemical signatures reflect the dissolution of halite and gypsum we observed positive correlations between temperature br b and si the temperature correlation with bromide likely documents the transformation of organically bound br the silica concentrations in low salinity aws southeast of the aral sea eastern basin are close to quartz saturation and define a chemical si geothermometer

geothermometry from brine analyses lessons from the gulf coast u s a abstract geothermometers based on mineral water equilibria are of limited use at temperatures characteristic of hydrocarbon production from sedimentary basins metastable detrital phases such as alkali feldspars and plagioclase persist to temperatures characteristic of the deepest wells sasmpled approaching 200 c and equilibria involving stable phases such as albite illite and quartz are not commonly achieved empirical relations such as that between mg and li are more successful in predicting subsurface formation water temperatures than are equilibrium relations involving quartz carbonates or feldspars the concentrations of most components in saline formation waters seem to be governed by kinetic rather than by equilibrium considerations

the remaking of the mengyejing potash deposit in yunnan china evidence from rb sr isotopic systematics abstract the mengyejing potash deposit mpd is the first significant ancient potash deposit ever found in china and it was considered to have formed during the middle to late cretaceous the 87 sr 86 sr ratios of potash bulk samples suggest that both bedded and veined potash orebodies of the mpd have been affected by igneous activity resulting from decompression melting of a metasomatically altered depleted mantle from 16 ma to present the rb sr isotopic systematics of the potash bulk samples define several apparent isochrons ranging from 0 609 0 026 to 14 23 0 63 ma with the maximum age being consistent with previous k ar ages of the k bearing minerals from the mpd such isotopic signatures imply that the mpd may have been affected by multiple stage fluid flow events since the mid miocene consisting of hydrothermal fluids continental fresh water and or hot spring water it is very likely that the mpd is still affected by fluid flow events in modern times the mineral assemblage of halite sylvite with minor amounts of carnallite was formed due to the recrystallization and diagenetic modification by hydrothermal fluids some characteristics of halite photomicrographs and inclusions and the lack of original halite chevron patterns are also supportive of the hypothesis that the deposit has undergone a diagenetic modification and dissolution recrystallization processes

storm tracks and barotropic deformation in climate models abstract the relationship between the time mean planetary scale deformation field and the structure of midlatitude storm tracks is studied in wintertime simulations of the national center for atmospheric research ncar community climate model and the national aeronautics and space administration nasa goddard earth observing system model model biases are determined by contrasting model simulations forced by observed ssts with parallel analyses of ncep ncar reanalyses barotropic diagnostics are employed to identify potential dynamical linkages between regional biases in the midlatitude storm tracks and the horizontal deformation field initial observational analyses confirm that synoptic eddies are optimally configured to transfer kinetic energy to the mean flow in the jet exit regions where strong stretching deformation exists in these regions the major axes of the synoptic eddies are aligned along the dilatation axes of the mean flow consequently mean flow advection stretches synoptic eddies a

a new process response coastal recession model of soft rock cliffs abstract the development of cliff erosion predictive models is limited by the complex interactions between environmental processes and material properties over a range of temporal and spatial scales current models incorporate a stochastic representation of cliff behavior based on assumptions regarding the magnitude and frequency of events in a probabilistic framework the new model presented here has been developed to incorporate the behavioral and mechanical characteristics of coastal cliffs which are dominated geologically by overconsolidated clays tills and an associated protective colluvial wedge this model is capable of providing precise and stable responses to some of the inherent uncertainties in cliff recession processes including those caused by different failure mechanisms e g colluvium generation groundwater and erosive tidal cycles material strength is incorporated using the unconfined compressive strength of the material that composes the cliff unlike previous models a calibration parameter is restricted to account for uncertainties linked to marine processes the mechanisms of cliffline retreat have been identified as slump and topple landslides once cliff material has fallen colluvium formation at the cliff foot is incorporated into the model using three different procedures according to the geomechanical characteristics of the debris the model is validated through profile evolution assessment at various locations of coastline retreat on the holderness coast uk higher groundwater content also produces an increase in the number and size of the slope failures the results represent an important step forward in linking material properties to the processes of cliff recession

reply to the comment by stephenson discussion of de lange w p and moon v g 2005 estimating long term cliff recession rates from shore platform widths engineering geology 80 292 301

recrystallization in quartz overgrowths quartz overgrowths are among the most volumetrically significant diagenetic phases in sandstones many combined petrographic and geochemical studies of quartz overgrowths rely heavily on the long held underlying assumption of their stability this study of sem cathodoluminescence sem cl imaging of quartz overgrowths from the jurassic khatatba formation of egypt calls this assumption into question these overgrowths preserve spectacular sem cl textures that can be interpreted as recrystallization fabrics there are three major growth zones in the overgrowths q1 to q3 in the first q1 fine sem cl zoning is preserved some with relict fibrous textures and smooth or bulging growth surfaces these textures could indicate initial precipitation as opaline silica chalcedony microquartz or some phase other than coarse quartz overgrowth in q1 there are discordant areas locally showing smooth and scalloped boundaries and filled with quartz with the sem cl character of later growth zones such textures suggest that earlier zones were crosscut by later phases of quartz the smooth and scalloped boundaries and their position in the overall framework of cements and grains are in places inconsistent with simple fracturing but are consistent with dissolution of earlier growth zones followed by filling with later quartz these features suggest that earlier growth zones were unstable and were replaced by coarsely crystalline quartz overgrowth such observations and other empirical and chemical considerations suggest that in some cases quartz overgrowths may result from recrystallization of less stable quartz and silica phases thus any study of sandstone diagenesis focused on quartz overgrowths should take this possibility into account

characteristics of sea cliff erosion induced by a strong winter storm in the eastern mediterranean abstract changes in sea cliff morphologies along the 30 km long sharon escarpment segment of israel s weakly cemented mediterranean eolianite cliff line were analyzed to gain quantitative insights into erosion characteristics associated with a high energy winter storm 10 20 year return interval ground based repeat lidar measurements at five sites along the cliff line captured perturbations of cliff stability by basal wave scouring during the storm subsequent post storm gravity driven slope failures in the cliff face above and return of the system to transient stability within several months post storm erosion which amounted to 70 of the total volume of cliff erosion documented resulted in dramatic local effects of up to 8 m of cliff top retreat and yet at the larger scale of the 30 km cliff line examined erosion during the storm and the year that followed affected less than 4 of the cliff length and does not appear to be above the average cliff length annual erosion implied by previously published decadal scale retreat rates along this sea cliff our results do not support a direct association between strong storm events and elevated erosion and retreat at the cliff line scale

geochemistry of tectonically expelled fluids from the northern coast ranges rumsey hills california usa tectonic compression has created abnormally high pressure on deep basinal fluids causing their expulsion from areally exposed upper cretaceous rock along the eastern margin of the california coast ranges the fluids emerge as near neutral perennial sodium chloride springs at high elevations with flow rates as high as 10 l per min higher spring discharges are more common around the exposure of a west vergent fault propagation fold axis spring waters range from 1000 to 27 000 mg l tds the least saline water 18o 7 5 closely represents local meteoric water that mixes with saline fluid 18o 5 3 and forms a slope of 3 5 on a d vs 18o plot a na 125 to 8000 mg l vs cl 150 to 17 000 mg l plot shows a linear dilution trend that extends close to but below the values for modern seawater calcium 75 3000 mg l is considerably enriched relative to seawater and forms a nonlinear trend with chloride in detail the na deficit defined by the difference between the measured na content and the na concentration on a hypothetical seawater dilution line is approximately balanced by the ca excess similarly defined by the seawater dilution line this relationship strongly suggests that the fluid is diluted seawater that is being modified by active albitization of plagioclase at different depths simultaneous b and 18o enrichment of the fluids accompanied by deuterium depletion further suggest that the seawater modification is influenced by clay diagenesis bicarbonate and sio2 concentrations show an inverse correlation with cl with most waters being saturated or slightly oversaturated with calcite and quartz at the discharge temperatures some freshwater springs with near meteoric stable isotope values may represent mixing of young groundwater from perched aquifers but in many cases the freshwater springs emerge along the same structures and have the same perennial nature as the saline fluids and expulsion of an older fresh groundwater component that is under abnormal fluid pressures cannot be ruled out basinal fluids elsewhere commonly show dilution trends with local meteoric water and in the case of the rumsey hills some of the dilute saline waters may indicate deep penetration of meteoric water 1 km in the pleistocene before the latest tectonic uplift geothermometry of the spring waters maximum 90 c suggest an origin from as deep as 4 0 km this depth is consistent with the depth of the core of a fault propagation anticline below the surface of the rumsey hills developed by active internal deformation of an east tapering wedge beneath the southwestern sacramento valley active tectonic compression causes near lithostatic fluid pressures in the shallow subsurface below the rumsey hills and volume strain within the core of the anticline that results in upward expulsion of the saline fluids from the indicated depths

decadal changes in the relationship between the tropical pacific and the north pacific 1 it has been recognized that the tropical pacific sea surface temperature sst anomaly associated with the el nino southern oscillation enso is closely tied to large scale atmospheric anomalies in the extra tropical region based on observational data this connection appears to have changed significantly since 1999 this study examines the characteristics of this connection during two sub periods 1980 1998 and 1999 2010 using cyclostationary empirical orthogonal function cseof analysis we found that the atmospheric anomalies induced by the enso alter the sst over the north pacific through surface heat flux change during the earlier period of 1980 1998 during the later period in contrast enso related atmospheric anomalies feature the north pacific oscillation npo pattern during winter which is characterized by a southward shift of the atmospheric center of action from its climatological position the npo related atmospheric anomalies extend to the subtropical pacific this extension potentially links midlatitude and tropical pacific variability through air sea interactions the physical change appears to alter the el nino characteristics into that of the central pacific el nino through the wind sst coupling mechanism this process may be related to the recent change in which the central pacific el nino occurs more frequently than the conventional eastern pacific el nino detailed descriptions of the physical changes between the tropical pacific and the north pacific are presented in this study along with the possible implications of this change

mineral water interaction fluid flow and frio sandstone diagenesis evidence from the rocks the spatial distribution of burial diagenetic cements in sandstones of the frio formation is related to permeability and fluid flow the relationship between sandstone diagenesis and fluid flow implies that the modification of the rocks is largely the outcome of reactions between the detrital and authigenic minerals and the formation water in the pores during burial formation water preferentially flowed through the most porous and permeable sandstones diagenetic alteration is more extensive in permeable sandstones because the minerals in those rocks were exposed to significantly more pore volumes of reactive water each of which accomplished a small amount of diagenetic work consequently porous and permeable units were also the preferred sites of diagenetic mineral p ecipitation the heterogeneous distribution of authigenic minerals in sandstones is a result of changing preferential flow paths due to diagenetic modification during burial sandstones that are not the most porous or permeable at the time of deposition commonly preserve the best reservoir quality at depth because they are less modified by diagenesis petrographic analyses indicate that the sio2 needed for the quartz overgrowths in the sandstones had an allochthonous source dgr18o values for diagenetic quartz imply that the mineral precipitated from rapidly ascending hot formation water quartz overgrowths are most abundant in distal shelf facies sandstones where the isolated nature of the sandstones in a predominately shaly section maximized preferential fluid flow mass balance calculations show that thousands of pore volumes of formation water are required to supply the sio2 needed for the quartz overgrowths in the sandstones the amount of water required to produce the diagenetic modification of the sandstones is much larger than the amount of water present in the entire frio formation impl ing that reuse of formation water is an important and necessary process during diagenesis

northern hemisphere mid winter vortex displacement and vortex split stratospheric sudden warmings influence of the madden julian oscillation and quasi biennial oscillation we investigate the connection between the equatorial madden julian oscillation mjo and different types of the northern hemisphere mid winter major stratospheric sudden warmings ssws i e vortex displacement and vortex split ssws the mjo ssw relationship for vortex split ssws is stronger than that for vortex displacement ssws as a result of the stronger and more coherent eastward propagating mjos before vortex split ssws than those before vortex displacement ssws composite analysis indicates that both the intensity and propagation features of mjo may influence the mjo related circulation pattern at high latitudes and the type of ssws a pronounced quasi biennial oscillation qbo dependence is found for vortex displacement and vortex split ssws with vortex displacement split ssws occurring preferentially in easterly westerly qbo phases the lagged composites suggest that the mjo related anomalies in the arctic are very likely initiated when the mjo related convection is active over the equatorial indian ocean around the mjo phase 3 further analysis suggests that the qbo may modulate the mjo related wave disturbances via its influence on the upper tropospheric subtropical jet as a result the mjo related circulation pattern in the arctic tends to be wave number one wave number two 25 30 days following phase 3 i e approximately phases 7 8 when the mjo related convection is active over the western pacific during easterly westerly qbo phases which resembles the circulation pattern associated with vortex displacement vortex split ssws

toward understanding the response of the tropical atmosphere ocean system to increased co2 using equilibrium asynchronous coupling we investigate the response of the tropical pacific climate system to a tripling of co2 in a coupled atmosphere ocean model equilibrium asynchronous coupling eac is used to diagnose the climatic forcing mechanisms our results corroborate those from most other coupled gcms which generally simulate an el nino like mean climate state under increased co2 this pattern is characterized by enhanced warming of the ocean surface in the equatorial pacific in conjunction with a reduction in the zonal sst gradient stronger atmospheric convection and precipitation in the central equatorial pacific a stronger subtropical westerly jet and a deepened wintertime aleutian low in association with a pna like geopotential pattern aloft we show that these climate changes are triggered by a weakening of the tropical walker circulation which leads to weaker surface easterly winds along the equator and therefore less oceanic upwelling furthermore the main el nino like atmospheric anomalies do not depend critically on the existence of an east west equatorial gradient either in the simulated modern ssts or in the sst anomalies under increased co2 regardless of the details of the sst boundary conditions the atmosphere seems to respond similarly to a co2 warming perturbation and in a manner that favors the evolution of the climate system toward an el nino like state an enhanced meridional atmospheric circulation in the pacific is linked to increased convection along the itcz coinciding with subtropical anomalies of higher surface pressure and stronger subsidence aloft this anomalous surface pressure pattern is much more pronounced in the northern hemisphere presumably due to a pna like atmospheric teleconnection these surface pressure anomalies produce a stronger meridional outflow of wind toward the equator and weaker easterly winds along the equator the weaker equatorial easterlies reduce oceanic upwelling in the central and eastern equatorial pacific thereby promoting a reduced east west sst gradient and a maximum warming in the central equatorial pacific around 140 170 w

low frequency variability in the midlatitude atmosphere induced by an oceanic thermal front abstract this study examines the flow induced in a highly idealized atmospheric model by an east west oriented oceanic thermal front the model has a linear marine boundary layer coupled to a quasigeostrophic equivalent barotropic free atmosphere the vertical velocity at the top of the boundary layer drives the flow in the free atmosphere and produces an eastward jet parallel to the oceanic front s isotherms a large gyre develops on either side of this jet cyclonic to the north and anticyclonic to the south of it as the jet intensifies during spinup from rest it becomes unstable the most unstable wave has a length of about 500 km it evolves into a meander and eddies detach from the eastern edge of each gyre the dependence of the atmospheric dynamics on the strength t of the oceanic front is studied the gulf stream and kuroshio fronts correspond roughly in the scaling used here to t 7 c for weak fronts t 4 c the circulation is steady and exhibits two large antisymmetric gyres sepa

observed patterns of month to month storm track variability and their relationship to the background flow month to month storm track variability is investigated via eof analyses performed on era 40 monthlyaveraged high pass filtered daily 850 hpa meridional heat flux and the variances of 300 hpa meridional wind and 500 hpa height the analysis is performed both in hemispheric and sectoral domains of the northern and southern hemispheres patterns characterized as pulsing and latitudinal shifting of the climatologicalmean storm tracks emerge as the leading sectoral patterns of variability based on the analysis presented storm track variability on the spatial scale of the two northern hemisphere sectors appears to be largely but perhaps not completely independent pulsing and latitudinally shifting storm tracks are accompanied by zonal wind anomalies consistent with eddy forced accelerations and geopotential height anomalies that project strongly on the dominant patterns of geopotential height variability the north atlantic oscillation nao northern hemisphere annular mode nam is associated with a pulsing of the atlantic storm track and a meridional displacement of the upper tropospheric jet exit region whereas the eastern atlantic ea pattern is associated with a latitudinally shifting storm track and an extension or retraction of the upper tropospheric jet analogous patterns of stormtrack and upper tropospheric jet variability are associated with the western pacific wp and pacific north america pna patterns wave mean flow relationships shown here are more clearly defined than in previous studies and are shown to extend through the depth of the troposphere the southern hemisphere annular mode sam is associated with a latitudinally shifting storm track over the south atlantic and indian oceans and a pulsing south pacific storm track the patterns of storm track variability are shown to be related to simple distortions of the climatological mean upper tropospheric jet

circumglobal teleconnection in the northern hemisphere summer analysis of the 56 yr ncep ncar reanalysis data reveals a recurrent circumglobal teleconnection cgt pattern in the summertime midlatitude circulation of the northern hemisphere this pattern represents the second leading empirical orthogonal function of interannual variability of the uppertropospheric circulation the cgt having a zonal wavenumber 5 structure is primarily positioned within a waveguide that is associated with the westerly jet stream the spatial phases of cgt tend to lock to preferred longitudes the geographically phase locked patterns bear close similarity during june august and september but the pattern in july shows shorter wavelengths in the north pacific north america sector the cgt is accompanied by significant rainfall and surface air temperature anomalies in the continental regions of western europe european russia india east asia and north america this implies that the cgt may be a source of climate variability and predictability in the above mentioned midlatitude regions the cgt has significant correlations with the indian summer monsoon ism and el nino southern oscillation enso however in normal ism years the cgt enso correlation disappears on the other hand in the absence of el nino or la nina the cgt ism correlation remains significant it is suggested that the ism acts as a conductor connecting the cgt and enso when the interaction between the ism and enso is active enso may influence northern china via the ism and the cgt additionally the variability of the cgt has no significant association with the arctic oscillation and the variability of the western north pacific summer monsoon the circulation of the wave train shows a barotropic structure everywhere except the cell located to the northwest of india where a baroclinic circulation structure dominates two possible scenarios are proposed the abnormal ism may excite an anomalous west central asian high and downstream rossby wave train extending to the north pacific and north america on the other hand a wave train that is excited in the jet exit region of the north atlantic may affect the westcentral asian high and thus the intensity of the ism it is hypothesized that the interaction between the global wave train and the ism heat source may be instrumental in maintaining the boreal summer cgt

factors controlling li concentration and isotopic composition in formation waters and host rocks of marcellus shale appalachian basin in this study water and whole rock samples from hydraulically fractured wells in the marcellus shale middle devonian and water from conventional wells producing from upper devonian sandstones were analyzed for lithium concentrations and isotope ratios 7li the distribution of lithium concentrations in different mineral groups was determined using sequential extraction structurally bound li predominantly in clays accounted for 75 91 wt of total li whereas exchangeable sites and carbonate cement contain negligible li 3 up to 20 of the li is present in the oxidizable fraction organic matter and sulfides the 7li values for whole rock shale in greene co pennsylvania and tioga co new york ranged from 2 3 to 4 3 similar to values reported for other shales in the literature the 7li values in shale rocks with stratigraphic depth record progressive weathering of the source region the most weathered and clay rich strata with isotopically light li are found closest to the top of the stratigraphic section diagenetic illite smectite transition could also have partially affected the bulk li content and isotope ratios of the marcellus shale in greene co southwest pennsylvania the upper devonian sandstone formation waters have 7li values of 14 6 1 2 2sd n 25 and are distinct from marcellus shale formation waters which have 7li of 10 0 0 8 2sd n 12 these two formation waters also maintain distinctive 87sr 86sr ratios suggesting hydrologic separation between these units applying a temperature dependent illitilization model to marcellus shale we found that li concentration in clay minerals increased with li concentration in pore fluid during diagenetic illite smectite transition samples from north central pennsylvania show a much smaller range in both 7li and 87sr 86sr than those in southwest pennsylvania spatial variations in li and 7li values show that marcellus formation waters are not homogeneous across the appalachian basin marcellus formation waters in the northeastern pennsylvania portion of the basin show a much smaller range in both 7li and 87sr 86sr suggesting long term cross formational fluid migration in this region assessing the impact of potential mixing of fresh water with deep formation water requires establishment of a geochemical and isotopic baseline in the shallow fresh water aquifers and site specific characterization of formation water followed by long term monitoring particularly in regions of future shale gas development

an electron microprobe study of detrital feldspar microprobe analysis of detrital alkali feldspar and plagioclase is useful in provenance studies detrital grains of alkali feldspar more sodic than 50 weight percent albite molecule are derived almost exclusively from volcanic sources alkali feldspar grains more potassic than 87 percent orthoclase molecule are derived from metamorphic and plutonic rocks for the more sodic varieties of detrital plagioclase it is possible to distinguish on the basis of potassium content between volcanic and non volcanic sources non volcanic albite and volcanic and non volcanic oligoclase and andesine are abundant forms of detrital plagioclase in tertiary sandstones from the southern colorado plateau area labradorite and bytownite are present as detrital grains in some deposits from this region most of the detrital alkali feldspar in these rocks is highly potassic containing more than 90 percent or molecule intermediate alkali feldspar is common in sandstones of volcanic and mixed provenance detrital plagioclase from several sandstones of mixed provenance contains between 0 to 0 7 percent fe and 0 to 0 5 percent sr alkali feldspar from the same samples contains between 0 and 0 5 percent fe and 0 and 1 5 percent ba detrital plagioclase interpreted as volcanic in origin generally contains more fe and sr than non volcanic plagioclase other approaches to the study of detrital feldspar with the microprobe are useful in provenance analysis chemical zoning of plagioclase established previously as a provenance tool can be studied more accurately and in more detail with a microprobe than with a petrographic microscope also sand sized volcanic lithic fragments can be classified as mafic intermediate or silicic in composition by analyzing their feldspar microphenocrysts

global view of the intraseasonal oscillation during northern winter abstract in this study svd analysis is applied to a normalized 200 mb streamfunction olr covariance matrix to extract the most recurrent coupled pattern in the northern winter after the removal of the climatological seasonal cycle and seasonal means for each winter the first two singular vectors are on an intraseasonal timescale and the combination of the two forms an oscillation it is characterized by eastward propagation in the indian ocean and the western pacific standing oscillations in both the tropics and the extratropics and the poleward propagation of a zonally symmetric structure although there exists an eastwardly propagating pattern the phase relationship between geopotential wind and streamfunction fields is inconsistent with that of equatorial kelvin waves eastward propagation is most evident in the tropics of the southern hemisphere while the signals in the northern hemisphere are characterized by standing oscillations the distinct characteristics of the northern and southern he

barotropic wave propagation and instability and atmospheric teleconnection patterns abstract a global barotropic model linearized about the 300 mb climatological mean january flow is perturbed by applying a series of localized forcings distributed throughout the tropics and subtropics structures which resemble the observed pacific north american and east atlantic teleconnection patterns noted by wallace and gutzler 1981 tend to recur in the responses similar patterns are found to result from the dispersion of isolated initial perturbations placed at a variety of locations in the tropics and midlatitudes it is shown that these structures are related to the most rapidly growing mode associated with barotropic instability of the zonally varying climatological basic state in the absence of damping this mode has an e folding time of about a week and a period close to 50 days in localized regions the instantaneous growth rates can be competitive with those of baroclinic instability these episodes of rapid local barotropic growth are interspersed with intervals in which the local

landslide hazard mapping along the coastline of the cilento region italy by means of a gis based parameter rating approach abstract this paper deals with the heuristic approach used for landslide hazard zonation along the coastal slopes and cliffs of the cilento region between agropoli and sapri italy this sector of coastline about 118 km in length is formed mainly of mesozoic carbonates and miocene flysch quaternary marine sandstones together with beach sands also crop out due to the destructive force of the waves the coastline is affected by several landslides mainly rock falls and slides the major geomorphological geological and structural features of about 154 slopes and cliffs have been analysed and several parameters affecting the rock masses were detected and measured these parameters deal with topographical geological geomechanical environmental and wave hydraulic characteristics of the studied area in order to perform the heuristic approach the rock engineering systems res proposed by hudson was adopted with several modifications the main steps of this work were 1 the choice of parameters relevant to landslide hazard zonation 2 the analysis of binary interaction between parameters 3 the weighting of interaction importance 4 the rating assignment to different classes of parameter values and 5 the final computation of an instability index i i a database containing the measured parameters was prepared and using an interaction matrix the outputs were linked into a geographic information system it contains the following elements geological and geomorphological features historical data regarding landslides images and values of i i for the studied slopes and cliffs if new landslides occur or near shore engineered structures are built then the i i values will be automatically upgraded values of the i i were grouped into 3 classes marking low medium and high landslide hazard both carbonatic rock masses and flysch were distinguished with respect to i i values to show the differences in landslide susceptibility in fact rapid but small rock falls can cause more casualties than moderate speed but large slides high landslide hazard affects about 41 of carbonate cliffs and about 53 of slopes in arenaceous marly flysch

dynamic response of a rocky cliff under the sea wave pulse a study along the adriatic coast of polignano apulia italy the dynamic behavior of a rocky cliff under severe sea waves has been analyzed in the location of polignano facing on the adriatic coast of apulia southern italy in this area the classical and at the same time complex problem of the stability of a cliff in calcareous rocks is burdened by the presence on the top of the cliff of the ancient town to analyze the behavior of the cliff under the impulsive transfer of energy generated by the sea waves two types of measures were carried out on the rocky mass 1 ambient noise and 2 strong motion records the first type of measures which may be executed in a short time with a high spatial density has provided a recognition of the intrinsic and anisotropic dynamic behavior of the coastal cliff the accelerometric records carried out during heavy storms in december 2009 and january 2010 allowed to evaluate the energy transfer from waves to cliff in terms of maximum values and temporal and directional distribution to facilitate a correct interpretation of the measures also a geomechanical characterization of the rocky mass has been carried out through the rock mass rating system bieniawski the geomechanics classification in rock engineering applications proceedings of the 4th isrm cong montreux pp 51 58 1979 bieniawski engineering rock mass classifications wiley new york p 251 1989 and the markland s test a useful technique for estimating the stability of rock slopes when the rigid wedge sliding type of failure is expected pp 10 1972 the first allowed to classify the rocky masses in terms of quality the second one to individuate the potential failure mechanisms of the cliff

the critical role of non normality in partitioning tropical and extratropical contributions to pna growth abstractthe pacific north american pna teleconnection pattern has been linked both to tropical phenomena including the madden julian oscillation mjo and el nino southern oscillation enso an

the modulation of the subtropical and extratropical atmosphere in the pacific basin in response to the madden julian oscillation abstract the 40 yr ecmwf re analysis era 40 data are combined with a number of novel climatologies to conduct a comprehensive examination of the response of the subtropical and extratropical atmosphere over the pacific basin to an evolving madden julian oscillation mjo event the adopted approach constitutes a symbiosis of a climatological analysis during the northern hemisphere winter from 1979 to 2002 and a case study analysis of a distinct mjo event that occurred in january february 1993 the former is designed to obtain the general characteristics observed during a composite mjo life cycle while the latter is used to provide insight into the instantaneous mechanisms responsible for the observed composite evolution a primary component of the study involves the diagnosis of anomalous wave breaking activity in response to mjo forcing in the form of tropical convection and or upper level divergence wave breaking events are separated by their characteristic life cycles lc1 anticyclonic and lc2 c

teleconnections from tropics to northern extratropics through a southerly conveyor rossby wave propagation theory predicts that rossby waves in a tropical easterly flow cannot escape from the tropics to the extratropics here the authors show that a southerly flow component in the basic state a southerly conveyor may transfer a rossby wave source northward thus a forcing embedded in the deep tropical easterlies may excite a rossby wave response in the extratropical westerlies it is shown that the southerly conveyor determines the location of the effective rossby wave source and that the extratropical response is relatively insensitive to the location of the tropical forcing provided that the tropical response can reach the southerly conveyor a stronger southerly flow favors a stronger extratropical response and the spatial structure of the extratropical response is determined by the extratropical westerly basic flows

comparison of short term seacliff retreat measurement methods in del mar california article i nfo seacliff retreat has been variously characterized as the recession rate of the cliff top of the cliff base and as the bulk recession rate based on volumetric changes of the entire cliff face here these measures of retreat are compared using nine semi annual airborne lidar light detection and ranging surveys of southern california seacliffs changes in the cliff base location where the steeply sloping cliff face intersects the beach include cliff retreat owing to basal erosion but also reflect changes in beach sand level and basal talus deposits averaged over the 2 5 km alongshore study span the cliff base actually prograded seaward about 12 cm during the 4 year study cliff top change was dominated by few relatively large several meters localized retreats cliff face changes that include failures and deposits anywhere on the cliff profile had a relatively small mean magnitude compared to cliff top changes and were more widely distributed alongshore however the similar alongshore averaged cumulative cliff top and net bulk cliff face end point retreat 14 and 19 cm respectively suggest that mean cumulative cliff top retreat can potentially be a viable surrogate for mean net cumulative cliff wide erosion and vice versa over relatively short time periods cliff face erosion occurred repeatedly at some locations confirming the presence of seacliff erosion hot spots during the study period

geology and geothermal origin of grant canyon and bacon flat oil fields railroad valley nevada eastern nevada s grant canyon and bacon flat oil fields show strong evidence of formation in a still active moderate temperature geothermal system modern manifestations of this system include unusually elevated oil reservoir temperature at shallow depth 116 122 c at 1 1 1 6 km and dilute na hco3 cl thermal waters directly associated with hot oil hydrogen and oxygen isotopic compositions indicate that these thermal waters are meteoric in origin but were probably recharged prior to the holocene before 10 ka the waters apparently ascended to oil reservoir elevations after deep heating in response to the normal regional thermal gradient there is no evidence for a modern magmatic heat source the beginning of oil reservoir evolution at both fields is recorded by late stage fracture filling quartz in the vuggy brecciated paleozoic dolostone reservoir rocks oil and aqueous solutions were trapped as fluid inclusions in the quartz at temperatures comparable to those now prevailing in the reservoirs apparent salinities of the aqueous inclusions closely match the actual concentrations of current oil field waters and the quartz has the oxygen isotopic composition predicted for its crystallization from these waters at contemporary temperatures present day and fluid inclusion temperatures define essentially coincident isothermal profiles through and beneath the oil reservoir interval a phenomenon consistent with near constant convective heat transfer since inception of the eothermal system textural and mineralogic clues indicate that hot waters circulating in this system also increased porosity by dissolving carbonate minerals and helped seal reservoir margins by precipitating silica and kaolin more importantly the rising thermal waters may have aided oil transport and accelerated source rock maturation through an increase in the shallow 3 km local thermal budget along with the aforementioned fluid inclusion and isotopic evidence radiometrically dated life spans for numerous extinct geothermal systems epithermal ore deposits in the basin and range make it likely that the grant canyon bacon flat system and associated oil reservoirs are no older than 2 5 ma

processes of coastal bluff erosion in weakly lithified sands pacifica california usa abstract coastal bluff erosion and landsliding are currently the major geomorphic processes sculpting much of the marine terrace dominated coastline of northern california in this study we identify the spatial and temporal processes responsible for erosion and landsliding in an area of weakly lithified sand coastal bluffs located south of san francisco california using the results of a five year observational study consisting of site visits terrestrial lidar scanning and development of empirical failure indices we identify the lithologic and process controls that determine the failure mechanism and mode for coastal bluff retreat in this region and present concise descriptions of each process bluffs composed of weakly cemented sands unconfined compressive strength ucs between 5 and 30 kpa fail principally due to oversteepening by wave action with maximum slope inclinations on the order of 65 at incipient failure periods of significant wave action were identified on the basis of an empirical wave run up equation predicting failure when wave run up exceeds the seasonal average value and the bluff toe elevation the empirical relationship was verified through recorded observations of failures bluffs composed of moderately cemented sands ucs up to 400 kpa fail due to precipitation induced groundwater seepage which leads to tensile strength reduction and fracture an empirical rainfall threshold was also developed to predict failure on the basis of a 48 hour cumulative precipitation index but was found to be dependent on a time delay in groundwater seepage in some cases

an analysis of a relatively rare case of continental blocking planetary and synoptic scale analyses of a relatively rare continental blocking event that occurred over north america during the spring of 1980 are undertaken to determine whether or not this event was different from its counterparts which occur over oceanic regions the planetary scale analysis demonstrates that during the spring season a ridge was located further inland over the north american continent and amplified with respect to climatology the position of this ridge may have been linked to a broad region of colder than normal sea surface temperatures found over the north central pacific during the spring season and much of the previous winter simple sutcliffe type and thermodynamic analyses of the accompanying lower tropospheric warm anomaly associated with the ridging show that lower tropospheric temperature advection and subsidence associated with anticyclonic vorticity advection by the time mean thermal wind produced much of the anomalous warmth a simple synoptic scale analysis was performed using both the zwack okossi zo equation and potential vorticity pv thinking approaches these complementary analyses demonstrated that synoptic scale cyclones were instrumental in the formation and maintenance and or intensification of this blocking event the pv analysis demonstrated that low pv air was swept polewards and then was advected over the blocking region sustaining the broad region of low potential vorticity associated with the block over north america the zo analysis showed that the advection of anticyclonic vorticity was the most important mechanism forcing geopotential height rises at 500 hpa over the block centre the region of low pv and zo height rises could be associated with the anticyclonic shear side of an upstream jet maximum typically found in association with developing and or intensifying blocking events thus negative pv advection correlated significantly with calculated zo height rises finally it is suggested that a favourable phase relationship between the upstream cyclones and the large scale ridge is necessary for block development or intensification

a new look at the midlatitude mjo teleconnection in the northern hemisphere winter the midlatitude to madden julian mjo teleconnection in the northern hemisphere wintertime was investigated using twenty years of outgoing long wave radiation and national center for atmospheric research national centers for environmental prediction re analysis data it is revealed through empirical orthogonal functions and regression analyses that the tropical upper level divergence convergence associated with enhanced reduced tropical convection has a subtropical counterpart of upper level convergence divergence as the convective region of mjo moves eastward from the indian ocean to the western pacific the divergent circulation connecting the tropics and subtropics moves eastward from an analysis of vertical motion diagnosed by the generalized omega equation it was revealed that the position of the subtropical rossby gyres of the mjo with respect to the asian pacific jet was the most important factor affecting the existence of the localized divergence convergence and associated lower level vertical motion in the subtropics as the subtropical rossby gyres pass by the longitudinal position of the asian pacific jet vertical motion occurs to meet the balance required by quasi geostrophic theory since this anomalous vertical motion is large enough to cause convection at that region the diabatic heating process reinforces the vertical motion furthermore other dynamical processes neglected in quasi geostrophic theory are activated and contribute to the vertical motion balancing the diabatic heating as a result of the vertical motion near the jet entrance region in the subtropics the vorticity advection by vertical wind and the tilting of vorticity become important since these two terms are similar in shape and magnitude they reinforce each other during the development phase of the midlatitude mjo teleconnection combining these two terms we define the baroclinic jet source bjs in order to evaluate the bjs as a source for the midlatitude mjo teleconnection a numerical experiment is carried out the linear barotropic model is forced by only two terms yet the model captured clearly the main feature of the midlatitude mjo teleconnection copyright 2006 royal meteorological society

piecewise tendency diagnosis of weather regime transitions abstract piecewise tendency diagnosis ptd is extended and employed to study the dynamics of weather regime transitions originally developed for adiabatic and inviscid quasigeostrophic flow on a beta plane ptd partitions local geopotential tendencies into a linear combination of dynamically meaningful source terms within a potential vorticity pv framework here ptd is amended to account for spherical geometry diabatic heating and ageostrophic processes and is then used to identify the primary mechanisms responsible for northern hemisphere weather regime transitions height tendency patterns obtained by summing the contributions of individual ptd forcing terms correspond very well to actual height tendencies composite ptd analyses reveal that linear pv advections provide the largest dynamical forcing for the weather regime development over the north pacific specifically linear baroclinic growth provides the primary forcing while barotropic deformation of pv anomalies provides a secondary contrib

dynamics of synoptic eddy and low frequency flow interaction part ii a theory for low frequency modes abstract amidst stormy atmospheric circulation there are prominent recurrent patterns of variability in the planetary circulation such as the antarctic oscillation aao arctic oscillation ao or north atlantic oscillation nao and the pacific north america pna pattern the role of the synoptic eddy and low frequency flow self feedback in the formation of these dominant low frequency modes is investigated in this paper using the linear barotropic model with the self feedback proposed in part i it is found that the ao like and aao like leading singular modes of the linear dynamical system emerge from the stormy background flow as the result of a positive self feedback this self feedback also prefers a pna like singular vector as well among other modes under the climatological conditions of northern winters a model with idealized conditions of basic mean flow and activity of synoptic eddy flow and a prototype model are also used to illustrate that there is a natural scale selection for the aao

the isotopic and chemical composition of co2 rich thermal waters in the mont dore region massif central france chemical and isotope compositions of fluid samples collected between 1974 and 1986 from 52 springs or shallow boreholes located in the mont dore region massif central france were examined some springs and wells were sampled several times during this period the fluids emerge from quaternary volcanic rocks or paleozoic granite at temperatures between 4 and 62 c and the origin of the h2o is meteoric the waters can be classified into three groups bicarbonate fluids mixed bicarbonate chloride fluids with a mineralization up to 8 g l and acid sulfate fluids only two fluids contain sufficient cl to be considered as mature waters previous work has demonstrated that they all contain partly mantle derived co2 gas and that the co2 rich gas phase and bicarbonate chloride waters are separated at substantial depth mineralized fluids circulate at depth and undergo several processes such as cooling or dilution with recent freshwater during their ascent to the surface therefore the co2 rich gas phase can be partly dissolved in the freshwater or in deep fluids after their dilution this process leads to the dissolution of surrounding rocks such dissolution is discussed on the basis of major element concentrations na k ca mg as well as the sr 87 86 isotope ratio dissolution of s bearing minerals has also been demonstrated the presence of the co2 rich gas phase also leads to isotope exchange between co2 and h2o some mineralized fluids are less affected by these processes than others in which case they display the chemical and isotopic characteristics of the original deep fluids it was shown that the applicability of geothermometer calculations for these waters is hampered by several processes that modify the chemical composition however some geothermometers can be used for estimating the temperature of the deep fluids using the chemical composition of the less modified fluids they indicate that fluids emerging from volcanic rocks in the dordogne valley reach temperatures of around 100 130 c at depth while the temperature of the fluid that issues from the granite at saint nectaire is 160 175 c at depth

energetics of the western hemisphere circulation pattern abstractthe western hemisphere wh circulation pattern identified by self organizing maps cluster analysis is a low frequency atmospheric regime that influences the fluctuations of large scale c

relationship between the tibetan plateau heating and east asian summer monsoon rainfall 1 this study reveals the close correspondence between the interannual variability of the dominant east asian summer rainfall pattern and the diabatic heating over the tibetan plateau in both spring and summer the heating fluctuation over the tibetan plateau is associated with two wave like circulation patterns which bear the characteristics of forced rossby wave emanating away from the deep heating the wave like pattern in turn affects the east asian summer rainfall because of the persistent heating over the tibetan plateau from spring to summer and its possible effect on the surrounding areas the heating index defined in this study can be used as a good predictor for the jja heating and precipitation distributions evidences shown suggest that external conditions other than the sst anomaly must be considered to understand the interannual variability of the east asian summer rainfall

chemical evolution of waters during long term interaction with granitic rocks in northern switzerland abstract as part of an assessment of crystalline rock as a potential host for a nuclear waste repository water samples were collected from more than 50 locations from the crystalline basement where it is under sedimentary cover in northern switzerland and where it is at the surface in the black forest these samples describe the changing chemistry of water in an extended flow system from dilute recharge waters far from chemical equilibrium with its host rock to saline waters at temperatures of 50 to 100 c with residence times far in excess of 105 a that have reached chemical equilibrium with their host rock this unique set of samples allows an analysis of the chemical evolution of granitic waters from surficial waters far from equilibrium to almost equilibrated waters mobile ions rare gases and isotopic data are used to estimate the extent of reaction between waters and their host rock the evolution of controlled elements is interpreted as a function of this extent of reaction silica contents correspond to approximate equilibrium even in the recharge waters the relative concentrations of ca and especially mg are significantly lower in the borehole waters than in recharge waters indicating a trend towards equilibrium the na k ratios correspond to equilibrium only in the most evolved older waters which are shown to be at full equilibrium

hydrocarbon system analysis in a rift basin with mixed marine and nonmarine source rocks the south viking graben north sea the south viking graben of the north sea is a prolific oil and gas province that has recoverable reserves of approximately 176 x 109 sm3 standard cubic meters 6 2 tcf gas 58 x 106 t 412 million boe natural gas liquids and 12 5 x 106 sm3 78 million bbl of black oil contained in the main fields sleipner vest sleipner ost and volve these fields are located primarily within block 15 9 in the norwegian sector and extend into neighboring blocks 15 6 and 16 7 the principal source of black nonvolatile oil is the late jurassic draupne formation which has a predominance of marine algal organic matter the lower section of the draupne formation together with the heather formation are organically leaner and contain a mixture of marine algal and terrigenous organic matter resulting in a potential to generate both oil and gas the middle jurassic hugin and sleipner formations contain humic coals and coaly shales with potential to generate gas and some light liquids these coals contain on average 80 90 vitrinitic woody material with occasional enrichment of resinite high resinite concentrations can lead to an overprediction of oil potential as they contribute significantly to the hydrogen index hi but generate primarily low molecular weight aromatic compounds all source rock facies types have reached maturities sufficient to generate oil and gas basin modeling suggests that onset of oil and gas generation started during the latest cretaceous early paleocene these source rocks have continued to yield oil and gas to the present day in many parts of the catchment area for the sleipner fields detailed geochemical analyses identified five main oil and condensate families family a comprises condensates and oil located in the northernmost part of sleipner vest and dagny generated from a marine clastic source with a predominance of type ii algal organic matter family b is condensates in the middle to southern part of sleipner vest generated from a source or a contribution from several source facies with mixed terrigenous higher plant organic matter and marine algal material family c consists of condensates reservoired in the jurassic of sleipner ost except well 15 9 a15 generated from a mixed algal terrigenous source but with a higher contribution of hydrocarbons from a marine algal source as compared with the sleipner vest family b family d comprises condensates in the jurassic triassic of loke and gungne in well 15 9 a15 from the crest of the sleipner ost structure as well as condensates within the paleocene sands of sleipner ost these condensates have a mixed terrigenous higher plant and marine algal signature and are derived from pre upper draupne formation sources family e is the black oil present in the jurassic volve field derived from a marine calcareous shale with type ii to ii s organic matter the source rock for this oil is unique in the greater sleipner area and is likely located in the isolated subgraben between the northern parts of sleipner vest and sleipner ost the hydrocarbon gases are broadly similar and are interpreted to have been generated from coals and coaly shales of the sleipner and hugin formations as well as those parts of the pre upper draupne section that have a predominance of terrigenous higher plant organic matter

geological analysis and stability assessment of a sea arch in palinuro southern italy abstract the study aims to describe the geological and geostructural layouts of an unstable sea arch located in a very attractive tourist area of southern italy on the basis of ad hoc field surveys and laboratory tests the problems of an in depth geo mechanical characterization of the rock mass are discussed in details and its main strength parameters are derived an indirect assessment of the possible geostatic stress field due to the neotectonic events which affected this sector of apennine range during the last 100 000 years is proposed and validated by means of numerical non linear fe analyses the results suggest that the presence of a lateral thrust acting into the promontory located at the back of the arch is very likely and its effects would agree well with the failures occurred in the past on the arch surfaces it is concluded that any possible intervention should be carefully designed on the basis of the highlighted factors and further investigations

nacacl saline formation waters frio formation oligocene south texas usa products of diagenesis abstract saline formation waters from reservoirs in oligocene deltaic clastic sedimentary rocks frio formation south texas are derived from three sources mixtures characterize most samples accounting for the wide range in chemistry low salinity water is derived from cenozoic shales in contrast saline water having variable br cl ratios is allochthonous and is derived from at least two sources in mesozoic strata which underly the cenozoic units saline water in this area regardless of br cl ratio contains variable high concentrations of ca calcium is derived primarily from dissolution of plagioclase as demonstrated by petrography 87 sr 86 sr analyses and chemical modelling the mccl 2 or carpenter function of saline formation waters in this area thus can be derived from water rock interaction and cannot be used to identify the ultimate source of solutes reverse osmosis is an unimportant processes in this area and 18 o and d values converge on rock buffered values of approximately 8 o and 30 o respectively

quantification of rock control in geomorphology abstract rock control the influence of rock properties on landform development has for long been a relatively under researched topic but numerous techniques have been developed especially by geotechnical engineers and stone conservationists that are now being applied to geomorphological issues by geomorphologists these techniques range in scale from the quantification of major discontinuities through to analysis of micro pores rock control studies that have taken place over the last few decades have contributed important insights into our understanding of such diverse phenomena as 1 river terraces bedrock channel forms and gradients pot hole development drainage density and gully badland development 2 slope forms and failures especially with respect to rock mass strength 3 the form of glacial troughs and of subglacial erosional landforms 4 weathering controls on rock durability and the association of weathering with porosity 5 classic karst features including various types of karren 6 sandstone landforms 7 inselbergs and tors and 8 cliffs and shore platforms

dynamics of low frequency variability barotropic mode the dynamics of low frequency variability is investigated in terms of sensitivity to the dependence of its relative zonal position of a single storm track in a simplified global circulation model a streamfunction tendency equation is derived that explicitly distinguishes between barotropic and baroclinic components one of the two low frequency patterns located in the center of the storm track grows barotropically and its decay is accomplished by low frequency eddy vorticity fluxes and the baroclinic contribution to the divergence term the growth and decay of the second pattern located at the downstream end of the storm track is dominated by nonlinear processes this indicates that the dynamical processes leading to growth and decay of low frequency patterns depend on the zonal position of the low frequency pattern relative to a storm track

origins of the 1988 north american drought the 1988 summer drought in the united states was the most extensive in many years because the drought developed in different places at different times not all regional effects can be traced to the same cause along the west coast and in the northwestern united states drought conditions developed during 1987 in association with the 1986 to 1987 el nino in the tropical pacific ocean record low rainfalls from april to june 1988 led to rapid development of drought in the north central united states strong anticyclonic conditions and a northward displaced jet stream in the upper atmosphere over north america throughout this period were only part of pronounced and distinctive wavetrain of anomalies in the atmospheric circulation that appeared to emanate from the tropical pacific below average sea surface temperatures along the equator in the pacific in the northern spring of 1988 combined with warmer than normal water from 10 degrees to 20 degrees n led to a northward displaced but still active intertropical convergence zone itcz southeast of hawaii results from a steady state planetarywave atmospheric model indicate that the atmospheric heating anomalies associated with the displaced itcz can force an anomalous wavetrain across north america similar to that observed land surface processes probably contributed to the severity and persistence of the drought however the large scale atmospheric circulation perturbations associated with natural variations in the coupled atmosphere ocean system in the tropical pacific were most likely the primary cause

mechanisms of meridional teleconnection observed between a summer monsoon system and a subtropical anticyclone part i the pacific japan pattern abstract summertime atmospheric circulation over the midlatitude western north pacific wnp is influenced by anomalous convective activity near the philippines this meridional teleconnection observed in monthly anomalies and known as the pacific japan pj pattern is characterized by zonally elongated cyclonic and anticyclonic anomalies around the enhanced convection center and to its northeast respectively in the lower troposphere with an apparent poleward phase tilt with height the authors idealized two layer linear model whose basic state consists of a zonal subtropical jet and a pair of a monsoon system and a subtropical anticyclone can simulate a pj like response against diabatic heating located between the pair each of the observed and simulated patterns can gain energy through barotropic and baroclinic conversions from the zonally varying baroclinic mean flow in an efficiency comparable with that of energy generation due to the anomalous diabatic heating indicating a characteristic of

diagenesis and reservoir quality prediction the modern concept of diagenesis was introduced by walther one hundred years ago to encompass the postdepositional processes that affect sediments from deposition to low grade metamorphism since walther 1893 diagenetic studies have been concerned with an extraordinary variety of chemical and physical interactions each of which has the potential to significantly affect the final composition and texture of a sedimentary rock the issues to which those studies have been applied are equally varied and include 1 improved techniques to predict the producibility of hydrocarbon reservoirs 2 improved techniques to predict subsurface fluid pressures 3 better constraints on the timing of fluid flow events 4 reconstruction of global climate change and 5 evaluation of groundwater contamination commercial applications of diagenetic studies have traditionally focused on the producibility of hydrocarbon reservoirs as such a review of this topic serves as an effective illustration of how basic research has been commercialized and a useful focus for the following dicussion however it is worth noting that decreased industrial research funding coupled with increased government funding for environmental research have recently resulted in a gradual evolution of diagenetic publications away from the producibility of hydrocarbon reservoirs toward the producibility of uncontaminated groundwater and other environmental issues despite the shift in emphasis many of the basic research issues remain unchanged whether one is focused on deep hydrocarbon reservoirs or shallow aquifers

observations of coastal cliff base waves sand levels and cliff top shaking concurrent observations of waves at the base of a southern california coastal cliff and seismic cliff motion were used to explore wave cliff interaction and test proxies for wave forcing on coastal cliffs time series of waves and sand levels at the cliff base were extracted from pressure sensor observations programmatically and used to compute various wave impact metrics e g significant cliff base wave height wave cliff interaction was controlled by tide incident waves and beach sand levels and varied from low tides with no wave cliff impacts to high tides with continuous wave cliff interaction observed cliff base wave heights differed from standard normal and rayleigh distributions cliff base wave spectra levels were elevated at sea swell and infragravity frequencies coastal cliff top response to wave impacts was characterized using microseismic shaking in a frequency band 20 45 hz sensitive to wave breaking and cliff impacts response in the 20 45 hz band was well correlated with wave cliff impact metrics including cliff base significant wave height and hourly maximum water depth at the cliff base r2 0 75 with site specific calibration relating wave impacts and shaking and acceptable anthropogenic traffic noise levels cliff top seismic observations are a viable proxy for cliff base wave conditions the methods presented here are applicable to other coastal settings and can provide coastal managers with real time coastal conditions copyright 2016 john wiley sons ltd

enso regulation of mjo teleconnection the extratropical teleconnections associated with madden julian oscillation mjo are shown to have an action center in the north pacific where the pressure anomalies have opposite polarities between the phase 3 convective indian ocean and phase 7 convective western pacific of the mjo the teleconnection in the same phase of mjo may induce opposite anomalies over east asia and north america between el nino and la nina years during mjo phase 3 a gigantic north pacific anticyclonic anomaly occurs during la nina making coastal northeast asia warmer wetter than normal but the west us colder drier whereas during el nino the anticyclonic anomaly is confined to the central north pacific hence the northwest us experiences warmer than normal weather under influence of a downstream cyclonic anomaly during phase 7 an extratropical cyclonic anomaly forms over the northwest pacific during la nina due to convective enhancement over the philippine sea causing bitter winter monsoon over japan whereas during el nino the corresponding cyclonic anomaly shifts to the northeast pacific due to enhanced convection over the equatorial central pacific which causes warm and wet conditions along the west coast of us and canada further the presence of enso induced seasonal anomalies can significantly modify mjo teleconnection but the aforementioned mjo teleconnection can still be well identified during phase 3 the mjo teleconnection pattern over north pacific will be counterbalanced enhanced by el nino la nina induced seasonal mean anomalies during phase 7 on the other hand the mjo teleconnection anomalies in the northeastern pacific will be enhanced during el nino but reduced during la nina thereby the impacts of mjo teleconnection on the north america is expected to be stronger during el nino than during la nina

intraseasonal teleconnection between the summer eurasian wave train and the indian monsoon this study investigated the most recurrent coupled pattern of intraseasonal variability between midlatitude circulation and the indian summer monsoon ism the leading singular vector decomposition svd pattern reveals a significant coupled intraseasonal variation between a rossby wave train across the eurasian continent and the summer monsoon convection in northwestern india and pakistan hereafter referred to as nism the wave train associated with an active phase of nism rainfall displays two high pressure anomalies one located over central asia and the other over northeastern asia they are accompanied by increased rainfall over the western siberia plain and northern china and decreased rainfall over the eastern mediterranean sea and southern japan the circulation of the wave train shows a barotropic structure everywhere except the anomalous central asian high located to the northwest of india where a heat induced baroclinic circulation structure dominates the time lagged svd analysis shows that the midlatitude wave train originates from the northeastern atlantic and traverses europe to central asia the wave train enhances the upper level high pressure and reinforces the convection over the nism region meanwhile it propagates farther toward east asia along the waveguide provided by the westerly jet after an outbreak of nism convection the anomalous central asian high retreats westward composite analysis suggests a coupling between the central asian high and the convective fluctuation in the nism the significance of the midlatitude ism interaction is also revealed by the close resemblance between the individual empirical orthogonal functions and the coupled svd modes of the midlatitude circulation and the ism it is hypothesized that the eastward and southward propagation of the wave train originating from the northeastern atlantic contributes to the intraseasonal variability in the nism by changing the intensity of the monsoonal easterly vertical shear and its associated moist dynamic instability on the other hand the rainfall variations over the nism reinforce the variations of the central asian high through the monsoon desert mechanism thus reenergizing the downstream propagation of the wave train the coupling between the eurasian wave train and nism may be instrumental for understanding their interaction and can provide a way to predict the intraseasonal variations of the indian summer monsoon and east asian summer monsoon

the continuum of north pacific sea level pressure patterns intraseasonal interannual and interdecadal variability this study combines k means cluster analysis with linear unidimensional scaling to illustrate the spatial and temporal variability of the wintertime north pacific sea level pressure slp field daily wintertime slp data derived from the ncep ncar reanalysis are used to produce 16 slp anomaly patterns that represent a discretized approximation of the continuum of north pacific slp patterns this study adopts the continuum perspective for teleconnection patterns which provides a much simpler framework for understanding north pacific variability than the more commonly used discrete modal approach the primary focus of this research is to show that variability in the north pacific on intraseasonal interannual and interdecadal time scales can be understood in terms of changes in the frequency distribution of the cluster patterns that compose the continuum each of which has a time scale of about 10 days this analysis reveals 5 6 pacific north american like pna like patterns for each phase as well as dipoles and wave trains a self organizing map som analysis of coupled slp and outgoing longwave radiation data shows that many of these patterns are associated with convection in the tropical indo pacific region on intraseasonal time scales the frequency distribution of these patterns in particular the pna like patterns is

the late fall extratropical response to enso sensitivity to coupling and convection in the tropical west pacific abstract the extratropical response to el nino in late fall departs considerably from the canonical el nino signal observational analysis suggests that this response is modulated by anomalous forcing in the tropical west pacific twp so that a strong fall el nino teleconnection is more likely when warm sst conditions and or enhanced convection prevail in the twp while these twp sst anomalies may arise from noise and or long term variability they may also be generated by differences between el nino events through variations in the tropical atmospheric bridge this bridge typically drives subsidence west of the date line and enhanced trade winds over the far twp which cool the ocean in late fall however some relatively weaker and or more eastward shifted el nino events produce a correspondingly weakened and displaced tropical bridge which results in no surface cooling and enhanced convection in the twp because the north pacific circulation is very sensitive to forcing from the twp at this time