what can we learn about crustal structure from thermal data thermal data represent a valuable remote sensing aid in studying crustal evolution heat flow q results from the heat loss by the cooling earth and from the heat production a of the radiogenic elements brought to the upper crust by magmatic intrusives heat flow is often observed to be linearly related to heat production the slope of this relation or thermal depth d has been used to infer a global upward enrichment in heat producing elements this thermal depth has been equated with the thickness of granites but such an interpretation has not been confirmed everywhere the depth to which granitic plutons are rooted can be computed from the inversion of gravity data it averages 7 2 km and is much smaller than the thermal depth granulite facies rocks are assumed to be present in the lower crust on the basis of seismic and geochemical data these rocks are generally depleted or initially poor in radiogenic elements u th k it is suggested that the thermal depth reflects the depth to the depleted layer in continental regions and that it corresponds to the granulitic layer in most places worldwide thermal and seismic data support this relationship although surface heterogeneities introduce complications thermal data can therefore be used to constrain the structure of the crust and its evolution through time

intensification variability of tropical cyclones in directional shear flows vortex tilt convection coupling abstractthe coupling of vortex tilt and convection and their effects on the intensification variability of tropical cyclones tcs in directional shear flows is investigated in this study the he

crustal heat production and mantle heat flow in central and eastern europe abstract the conversion of seismic velocity p into radiogenic heat production a enables the distribution of crustal heat sources to be estimated this technique was used to assess the mantle moho heat flow for 49 seismic velocity depth profiles located along five continental traverses in central and eastern europe the effect of pressure and temperature on p was taken into account as was the age dependence of a the uppermost part of the crust is dominated by microcracks that may have allowed a certain redistribution of radioactive elements by deep groundwater migration furthermore owing to the highly variable value of the pressure derivative of v p in the uppermost crust the use of a a p relationship is problematic within this depth range this radioactivity enriched zone the thickness of which can be determined from the parameters of the heat flow heat production relationship was therefore treated separately according to the model adopted for the upper crust the moho heat flow ranges from 14 to 26 mw m 2 in the stable continental areas such as the shields or ancient platforms younger terrains are characterized by elevated moho heat flows of 20 to 40 mw m 2 and the moho heat flow may eventually attain values over 50 mw m 2 in regions characterized by very high surface heat flow such as the pannonian basin for example the present data were compared with crustal models proposed by other authors moho heat flow estimates based on a simple exponential distribution of heat sources valid for the whole crust might be too high if applied to stable continental crust our data confirm a considerable variability in the mantle heat flow corresponding to the large scale tectonothermal evolution with a generally lower moho heat flow typical of consolidated stable continental crust the discrepancy in relation to the above estimates can be accounted for by a heat generation hump beneath an upper zone of exponential decline

the evolution of vortex tilt and vertical motion of tropical cyclones in directional shear flows abstractrecent studies have demonstrated the importance of moist dynamics on the intensification variability of tropical cyclones tcs in directional shear flows here we propose that dry dynamic

heat flow density measurements in the sediments of three lakes in northern sweden abstract heat flow density measurements in the sediments of three lakes 36 m 73 m and 99 m deep were carried out during a period of 3 5 years the gradient measurements were made from ice during the winter season with a bullard type probe with nine thermistors 0 5 m apart the thermal conductivity was measured in situ corrections were made for the disturbing temperature wave in the horizontally stratified sediments caused by seasonal variations in the bottom water temperature it is clearly shown that the differences in bottom water temperatures between different years can be fully corrected for only by very long time series the heat flow density values obtained are compared with measurements in boreholes and they seem to be correct to within 20 30

a seafloor observatory to monitor gas hydrates in the gulf of mexico gas hydrates are solid structures composed of gas molecules encased in cages of water molecules most interesting to the energy community are hydrates that contain hydrocarbon gases in the northern gulf of mexico hydrates of this type form in water depths greater than 450 m and often occur in mounds located where faults intersect the seafloor typically these hydrates consist of seawater from which the salt has been excluded and gases that have migrated up faults from buried hydrocarbon reservoirs in addition to hydrates the mounds contain large amounts of calcium carbonate and various other minerals precipitated by microbes that extract energy from hydrocarbon fluids

the effect of vertical shear orientation on tropical cyclogenesis the effect of the relative orientation of the vertical wind shear to the surface wind on tropical cyclogenesis is explored in environments of radiative convective equilibrium rce through numerical simulation this study serves as a companion paper to an earlier study on the thermodynamics of genesis in rce it is found when the mean surface wind and shear are aligned a negative surface wind anomaly arises from the superposition of the mean and vortex surface flows left of the shear vector the resulting weak surface enthalpy fluxes and up shear quasi balanced subsidence leads to dry air being located cyclonically down wind of the down shear convective anomaly thus convection is inhibited from propagating cyclonically around the core leading to a large down shear vortex tilt conversely in a counter aligned orientation the negative surface wind anomaly and driest air is found right of the shear vector hence the driest air rotates into the down shear flank where it moistened by shear organized convection furthermore the boundary layer is relatively moist left of shear due to the positive surface wind anomaly therefore promoting the cyclonic propagation from down shear and constraining the magnitude of the vortex tilt genesis is intimately tied to the magnitude of the tilt and is found to occur once the mid level vortex has precessed into the up shear flank for smaller values of maximum tilt vortex precession is comparatively rapid aided by showerhead moistening provided by the up shear advection of frozen condensate aloft with the up shear flank pre moistened rapid precession of the mid level vortex at smaller radii leads to near saturation on the mesoscale and the onset of rapid intensification when the magnitude of the tilt is quite large precession is much slower and the showerhead effect is significantly reduced until just prior to the emergence of the mid level vortex in the up shear flank copyright 2011 royal meteorological society

infill of tunnel valleys associated with landward flowing ice sheets the missing middle pleistocene record of the nw european rivers 1 the southern termination of the middle and late pleistocene scandinavian ice sheets was repeatedly located in the southern north sea sns and adjacent north sloping land areas giant meltwater excavated valleys tunnel valleys formed at the southern termination of the ice sheets and contain a hitherto enigmatic succession of northward prograding clinoforms comprising 1000s km3 of sediment this study analyses 3d seismic data covering the entire sns and demonstrates for the first time that the formation of these tunnel valleys was separate from their infill the infill constitutes the postglacial record of the nw european river deltas which had so far been considered missing

the variation of heat generation density and seismic velocity with rock type in the continental lithosphere abstract the petrophysical properties radioactive heat generation compressional wave velocity and density are related to rock type in crystalline rocks the cation fraction in the rock forming minerals is applied to determine the relationships quantitatively heat generation exhibits considerable variation with rock type as well as with the geologic age of the rocks therefore the relation between heat generation and rock type has been split into a relation for phanerozoic rocks and another for precambrian rocks which exhibit significantly lower heat generation only 1 3 of that of phanerozoic rocks the interrelations between the petrophysical properties are applied to fennoscandia precambrian terrane and southern bavaria northern alpine foreland phanerozoic rocks to estimate the heat generation by radioactivity in the crust and the heat flow density from the upper mantle

multiple resolution seismic imaging of a shallow hydrocarbon plumbing system woolsey mound northern gulf of mexico abstract the northern gulf of mexico is dominated by salt tectonics resulting fracturing and numerous seafloor seeps and vents woolsey mound site of the gulf of mexico hydrates research consortium s seafloor observatory has been investigated extensively via surveys direct sampling and seafloor instrument systems this study presents an innovative approach to seismic data interpretation integrating three different resolution datasets and maximizing seismic coverage of the complex natural hydrocarbon plumbing system at woolsey mound 3d industry seismic data reveal the presence of a salt body at in the shallow subsurface that has generated an extended network of faults some extending from the salt body to the seafloor master faults higher resolution seismic data show acoustic wipe out zones along the master faults with expulsion features seafloor pockmarks and craters located immediately above them and associated in the subsurface with high amplitude negative anomalies at constant depth of 0 2 s twtt b s f interpreted as free gas since pockmarks and craters provide pathways for hydrocarbons to escape from depth into the water column related sub surface seismic anomalies may indicate free gas at the base of the gas hydrates stability zone ghsz fluid flow and gas hydrates formation are segmented laterally along faults gas hydrates formation and dissociation vary temporally in the vicinity of active faults and can temporarily seal them as conduits for thermogenic fluids periodic migrations of gases and other fluids may perturb the ghsz in terms of temperature and pressure producing the observed lack of classical bsrs

physical oceanographic conditions in the deepwater gulf of mexico in summer 2000 2002 abstract the circulation and distribution of water properties in the water column of the gulf of mexico influence the flux of carbon to the benthic environment the eddy field of the upper 1000 m creates environmental conditions that are favorable for biological productivity in an otherwise oligotrophic subtropical ocean this eddy field results in the transport of nutrients and organic matter into the photic zone through cross margin flow of shelf waters upwelling in cyclones and uplift from the interaction of anticyclones with bathymetry these conditions then allow the productivity that becomes a possible source of carbon to the benthos data from four cruises during summers of 2000 2002 are used to describe the currents and water property distributions in the deepwater gulf of mexico which consists of water depths greater than 400 m comparisons are made to historical data sets to provide an understanding of the persistence of the characteristics of the gulf and the processes that occur there the currents in the gulf are surface intensified have minimum in 800 1000 m depths and also exhibit bottom intensification especially near sloping topography historical time series records show current speeds near bottom reach 50 100 cm s 1 at basin scales these currents tend to flow cyclonically counter clockwise along the bathymetry these near bottom episodic high speed currents provide a mechanism for the transport of organic material in both large and small particle sizes from one benthic area to another the distributions of temperature salinity nutrients and dissolved oxygen during the study appear to be unchanged from historical findings the source waters for the deep gulf are the water masses brought into the gulf by the loop current system the properties in the upper 100 200 m are the most variable of the water column consistent with their proximity to wind mixing river discharge mixing and atmospheric influences below 1500 m there are no major horizontal variations in these water properties

indications of a link between seismotectonics and ch4 release from seeps off costa rica measurements of ch4 concentrations in the bottom water during two discrete sampling periods in subsequent years above different cold seeps at the pacific margin off costa rica indicate large scale variations of ch4 release ch4 is emitted from mud extrusions and a slide scar at 1000 2300 m water depth maximum ch4 concentrations were found to be lower above all investigated sites in autumn 2003 than in autumn 2002 although seep sites are up to 300 km apart tidal and current changes were observed but found to apply only to individual seep sites increased seismic activity connected to the moment magnitude m w 6 4 earthquake offshore costa rica in june 2002 could have had an impact on all seep sites and thereby caused an increase in ch4 emission this is supported by the largest variations of ch4 concentration found above mud extrusions located above faults likely more strongly affected by tectonic movements even though our data indicate a relation between seismicity and ch4 seepage the relation is not proven and future work is needed to comprehensively test this hypothesis

a theory for strong long lived squall lines abstract we study herein the mechanics of long lived line oriented precipitating cumulus convection squall lines using two and three dimensional numerical models of moist convection these models used in juxtaposition enable us to address the important theoretical issue of whether a squall line is a system of special long lived cells or whether it is a long lived system of ordinary short lived cells our review of the observational literature indicates that the latter is the most consistent paradigm for the vast majority of cases but on occasion a squall line may be composed of essentially steady supercell thunderstorms the numerical experiments presented herein show that either type of squall line may develop from an initial line like disturbance depending on the magnitude and orientation of the environmental shear with respect to the line with shallow shear oriented perpendicular to the line a long lived line evolves containing individually short lived cells our analysis of this type o

reawakening of a volcano activity beneath eyjafjallajokull volcano from 1991 to 2009 abstract the ice capped eyjafjallajokull volcano south iceland had been dormant for 170 years when the first signs of reawakening of the volcano were captured by seismic and geodetic measurements in 1994 these were the first clear observed signs of unrest followed by 16 years of intermittent magmatic unrest culminating in 2010 when two eruptions broke out on the flank and at the summit we analyze seismic data from 1991 through 2008 and gps data from 1992 to may 2009 to infer magma movements beneath the volcano the relocated earthquakes reveal an overall pipe like pattern northeast of the summit crater sporadically mapping the pathway of magma from the base of the crust towards an intrusion in the upper crust during the study period three major seismic swarms were recorded two of them in 1994 and 1999 2000 occurred in the upper and intermediate crust and accompanied crustal deformation centered at the southeastern flank no uplift was detected during the 19 to 25 km deep 1996 swarm near the crust mantle boundary but the horizontal e w oriented t axes indicate a period of tension opening suggesting magma intruding up into the base of the crust the gps measured deformation during 1999 2000 can be modeled as intrusion of a horizontal circular sill with volume of 0 030 0 007 km3 at 5 0 1 3 km depth the less constrained 4 5 to 5 km deep sill model for the 1994 episode indicates a three times smaller intruded volume 0 011 km3 than during 1999 2000 in the years between following the intrusions contraction was observed at the southeastern flank the contraction from 2000 5 to 2009 3 can be fitted by a circular sill model with a volume contraction of 0 0015 0 0003 km3 year at 5 5 2 0 km depth the less well constrained model for 1994 7 to 1998 6 gives a volume contraction of 0 0009 0 0010 km3 at a fixed depth of 5 km the accumulated volume changes 0 013 km3 for the second period 0 0037 km3 for the first period are much larger than expected due to solidification and cooling of magma alone and might partly be explained by the underestimated volume of intruded magma mass loading effects within the crust due to the intruded magma and possibly and to less extent degassing co2

formation of rapidly sinking oil associated marine snow abstract significant amounts of oil accumulated at the sea surface and in a subsurface plume during the deepwater horizon dwh spill in the gulf of mexico gom in 2010 a substantial fraction of this oil was removed from the marine environment by mechanical recovery or burning or it reached shorelines whereas another fraction remained within the marine environment where it dispersed chemically or naturally emulsified or sedimented after the dwh accident the sedimentation of hydrocarbons to the seafloor via rapidly sinking oil associated marine snow has become a focus of attention and it has been hypothesized that marine snow formation significantly impacted the distribution of the oil from the dwh spill here roller table experiments are presented that investigated the conditions inducing the formation of oil associated marine snow focusing especially on the effects of oil type photochemical aging of oil and the presence of phytoplankton or dispersant large mucus rich marine snow termed microbial marine snow formed in treatments incubated with the oil that had accumulated at the sea surface this bacteria mediated formation of up to cm sized marine snow in the absence of particles 1 m represents a unique formation pathway different from that of the physical coagulation of particles microbial marine snow albeit smaller also formed in the presence of crude oil that had been aged for 3 weeks in sunlight but no particles formed in the presence of unaltered crude the dispersant corexit 9500a corexit oil ratio 1 100 impeded the formation of microbial marine snow requiring a re evaluation of the benefits and detriments of corexit 9500a as a mediating measure phytoplankton aggregates also incorporated fossil carbon providing an alternate pathway for the formation of oil associated marine snow the ubiquitous formation and rapid sedimentation of oil rich marine snow can explain the high accumulation rate of flocculent material at the seafloor and on corals observed after the dwh spill these results may raise awareness that oil spill response and assessment need to include sedimentation of hydrocarbons via marine snow as a significant distribution mechanism and may guide future modeling efforts and budget calculations

a new quantitative weathering classification for igneous rocks the description and classification of the rocks provide important information for geotechnical modeling in order to predict their engineering behaviors one of the most imperative parameters influencing the engineering behaviors of the rocks is the degree of weathering therefore it is evident that a realistic weathering classification is necessary mostly for establishing the geotechnical models in the engineering geology studies for this reason development of a qualitative weathering classification is the main purpose of the present study the weathering state parameter has been first created by describing the chemical and physical changes separately owing to weathering by employing the ultrasonic wave velocity in the rock material then a quantitative weathering index was introduced by combining the weathering condition and the slake durability known as the indicator of the rock soil ratio in the rock material finally this index obtained was applied on the prediction of the engineering properties of the harsit granitic rocks giresun ne turkey as a consequence of this study it has been determined that the engineering properties of the samples and the numerical index proposed could be predicted in addition the use and the limitations of the index introduced herein were discussed

lispb delta a lithospheric seismic profile in britain analysis and interpretation of the wales and southern england section abstract the lithospheric seismic profile in britain lispb shot in 1974 included a 310 km profile lispb delta crossing the palaeozoic welsh basin the western extent of the midland microcraton and the cornubian zone of southern england this first comprehensive analysis of these data has produced a sub horizontally layered seismic and associated gravity model that correlates well with surface geology a north south decrease in crustal velocity and density corresponds to the change from avalonian crust into the rheno hercynian zone at the south end of the profile high velocities and densities in the lowest crustal layer beneath north wales are proposed to result from cenozoic and possibly ordovician igneous intrusive rocks the former derived from an upwelling plume associated with the opening of the north atlantic examination of the load distribution throughout the model shows that it is strongly correlated with the earthquake distribution along lispb delta earthquake focal depth also correlates with heat flow a simple heat flow profile has been derived and the seismic velocity model used to constrain crustal heat production values a long wavelength excursion from published data can be explained in terms of an increase in mantle heat flow resulting from a previously identified deep thermal anomaly beneath the irish sea supplementary material normalised synthetic and true amplitude seismic record sections including picks and modelled phases for shots sp04 sp05 sps1 sps2 are available at http www geolsoc org uk sup18450

thermophysical properties of the earth s crust in situ measurements from continental and ocean drilling knowledge of the variation of thermal conductivity and heat production with depth is critical to understanding the thermal state of the crust continental and oceanic drill holes provide unique opportunities for the calibration of empirical and theoretical models relating crustal thermal properties to physical and chemical properties these calibrations are based on more than 30 000 well log measurements of acoustic velocity both compressional and shear density porosity radioelement concentrations k u th and major element chemistry al si ca fe s mg na in formations ranging in age from 5 to 620 ma and in composition from granitic to gabbroic the mineralogical data available from induced gamma ray spectroscopy logs when combined with known mineral thermal conductivities in a model for the thermal conductivity of a crystalline aggregate enable the in situ application of a laboratory estimation technique and yield continuous conductivity profiles however mineralogy based conductivity models cannot account for the anisotropic conductivity observed in foliated metamorphic rocks a phonon conduction model which utilizes acoustic velocity and bulk density measurements is accurate within 15 in both isotropic and anisotropic formations of the upper continental crust and in oceanic crustal layers 2c and 3 in oceanic crustal layers 2a and 2b however the effects of fracturing on compressional and shear velocities lead to inaccurate results the heat flow heat production relationship which provides one method of determining subsurface heat production has well documented limitations allis 1979 and rybach and buntebarth 1982 1984 on the basis of laboratory measurements have proposed quantitative relationships between heat production and rock compositional and physical properties the well log k u and th data indicate that heat production can be predicted from compositional data within a factor of 2 or 3 predictions of heat production from acoustic velocity and bulk density measurements are only accurate to within an order of magnitude three factors account for these results 1 the natural variability of velocity and density for a given rock composition 2 the tendency of u and th to associate with secondary rather than primary minerals and 3 u and th redistribution through fluid flow and metamorphism thus seismic velocity based heat production profiles can at best be taken as first order estimates which may misrepresent the complexity of the continental crust however the correlation of formations of known heat production with subsurface structures when combined with a suite of existing techniques for estimating heat production may lead to more accurate results

a model of the deep structure of the northeastern part of the baltic shield based on joint interpretation of seismic gravity magnetic and heat flow data abstract we have combined gravimetric geothermal and magnetic data with seismic results to characterize the crust of the northeastern part of the baltic shield the thickness of the crust varies between 31 and 48 km and four internal layers can be distinguished each with different physical properties and possibly with different geological origins a joint analysis of seismic and gravity data was used to construct maps of the moho relief and of the crust mantle transition layer our proposed one dimensional geophysical crustal model of the baltic shield may be considered as a basis for more detailed investigations

the heat flow heat generation relationship implications for the nature of continental crust abstract the apparent linear relationship between surface heat flow q and heat generation a is usually interpreted in terms of heat flow provinces i e terrains that have a common tectonothermal history and a uniform mantle component of heat flow the slope d of the linear regression of heat flow on heat generation is an indication of the thickness of the upper heat producing layer for many terrains d is numerically similar to the depth of a major mid crustal transition zone these observations are modelled by a two layer crust consisting of an upper layer approximately 10 15 km thick of variable heat generation underlain by a layer about 20 km thick in which heat generation is lower and more uniform than that in the upper layer the model is well able to simulate q a regression parameters for different sets of real data it is also consistent with other geological and geophysical observations the higher and more variable heat generation of the upper layer is consistent with ideas concerning removal of heat producing elements from the lower layer during amphibolite to granulite metamorphism and their redistribution into the upper crust further redistribution of heat producing elements may occur in zones of hydrothermal circulation whose depth is a function of stress pressure and temperature and which may migrate vertically in response to stress changes during uplift and erosion large scale metamorphism to granulite facies has been postulated as one mechanism for stabilisation of continental crust in the late archaean it is shown however that redistribution of heat producing elements in such a process would have only a small effect on crustal geotherms so that partitioning of heat production was not a major factor in the crustal stabilisation

factors controlling the variances of seismic velocity density thermal conductivity and heat production of cores from the ktb pilot hole this paper presents a statistical analysis of about 50000 petrophysical data measured on core samples from the continental deep drilling project ktb of the federal republic of germany the scattering of the data must be taken into consideration using empirical relationships between pairs of parameters e g sound velocity density heat production and thermal conductivity such covariances of parameters were calculated and used to find the principle components by applying factor analysis the reduction of parameters by factor analysis may help other scientists to concentrate on the essential parameters to be measured about 50 of the variance of all data can be explained by one background variable the so called lithology factor the variables that load a factor are either highly correlated or anticorrelated the lithology factor combines gamma spectroscopy data density and the mineral contents of quartz amphibole garnet and white mica seismic velocities and porosity data however were less well related to the lithology factor therefore the ktb data indicate that correlation between seismic velocity and one of the lithology factor loading variables is unlikely the lithology factor distinguishes 3 major rock types metabasites gneisses and an intermediate type the variance of the petrophysical parameters within the rock types plotted in crossplots show the level of validity of commonly used relationships among these parameters measurements under ambient and simulated in situ conditions are included to enable discussion of chemical mineralogical and microstructural characteristics of the rocks

tides of mississippi sound and the adjacent continental shelf abstract hourly water level and current data were collected in mississippi sound and the adjacent continental shelf from april 1980 to october 1981 amplitudes and epochs of the principal tidal constituents were calculated for each location the data were used to construct cotidal charts and describe characteristics of the predominant diurnal tide the pattern of the diurnal partial tides on the shelf is explained by reflection of first class waves propagating normal to the coast the period of the k 1 tide equals the inertial period just offshore of mississippi sound the resulting diurnal shelf currents are sverdrup waves with typical speeds of 5 10 cm s 1 the tidal wave is transformed into a rectilinear shallow water wave as it enters the tidal inlets of mississippi sound the form number of the shelf currents changes from 8 5 to 2 1 in the inlets due to enhancement of the semidiurnal currents this is a result of continuity constraints which transform currents in the inlets within mississippi sound the tidal waves shoal and become increasingly progressive in response to bottom friction

pn velocity and cooling of the continental lithosphere average upper mantle p sub n velocities and heat flow were computed within continental physiographic provinces in north america from published data p sub n velocity and heat flow data display an inverse relationship and were found to correlate with a statistically significant correlation coefficient temperatures at the crust mantle boundary were estimated from the heat flow values and these were used to demonstrate a correlation between p sub n velocity and temperature of upper mantle material the value of partialp sub n partialt p thus obtained 4 4 x 10 sup 4 to 8 1 x 10 sup 4 km s sup 1 sup 0 c sup 1 is within the range of temperature derivatives determined from laboratory studies of ultramafic rocks this dependence of p sub n velocity on temperature implies that one possible explanation for the observed geographical distribution in upper mantle seismic velocity is that the variation in p sub n velocity is primarily a temperature effect combined with the relationship between heat flow and crustal age for continents the p sub n versus heat flow correlation suggests a relationship between p sub n velocity and crustal age probably due to progressive cooling of the continental lithosphere after a thermotectonic event

one dimensional thermal models constrained by seismic velocities and surface radiogenic heat production for two main geotectonic units in southern portugal new heat flow density data and radiogenic heat production values obtained in southern portugal along with lithologic and structural data inferred from vertical seismic velocity distributions from deep seismic refraction surveys are used to construct one dimensional 1d geotherms for the crust in the two main geotectonic units of the region i e the ossa morena zone omz and the south portuguese zone spz surface radiogenic heat production values calculated using potassium uranium and thorium concentrations measured in different rock types were used to constrain the heat production values in the ossa morena zone and south portuguese zone the surface radiogenic heat production does not exceed 3 w m3 geotherms were constructed considering that the crust in the region has a three layer structure as inferred from seismic refraction surveys but with different thicknesses in the omz and spz for both zones two 1d models with constant and exponential heat productions were constructed the models suggest that temperatures are higher in the spz than in the omz the difference reaching values of about 300 c at moho depths however heat production values in the former are less constrained than in the latter and so temperatures in the spz are probably overestimated for each geotectonic unit no significant difference is observed in the results when constant heat production is assumed for the upper crust or an exponential decrease is assumed for the upper crust

relationships between the petrophysical properties density seismic velocity heat generation and mineralogical constitution the petrophysical properties density p compressional wave velocity v p and heat generation a exhibit considerable variation with rock type to characterize a given rock quantitatively a single parameter the cation fraction expressed by the k value has been found to be suited best 100 crystalline rocks have been sampled to cover the widest possible range in k value from silicic types like granophyres and granites through granodiorites tonalites diorites gabbros amphibolites hornblendites pyroxenites to ultrabasic rocks p k a and v p were determined experimentally the latter at 0 5 kbar 50 mpa the interrelations between these properties were established by regression analysis the relation k and v p k show a linear dependence whereas a k a and a v p follow exponential laws in a w m 3 12 20 230 5 k mole cm 3 in a 22 5 8 15 g cm 3 and in a 16 5 2 74 v p km s all correlation coefficients are better than 0 9

the depth dependence of heat production in the continental lithosphere derived from seismic velocities an experimentally established relationship enables the conversion of compressional seismic velocity to heat production a the conversion performed for 47 characteristic seismic sections from various tectonic units in central and eastern europe yields a general decrease of a with depth z the pattern of decrease depends on geological age young tectonic units with high heat flow exhibit a more rapid decrease the depth dependence of a does not follow the simple exponential law a z a o exp z d the logarithmic decrement d has the dimension length in general d decreases with depth from 20 30 km at 10 km depth to less than 10 km at the moho in the uppermost 10 km of the crust a certain redistribution of the heat producing radioelements u and th can occur by deep groundwater migration through microcrack networks below the moho heat production attains values which represent only insignificant contributions to heat flow through or to temperature field changes in the lithosphere

effects of low level flow orientation and vertical shear on the structure and intensity of tropical cyclones abstractthis article explores the simultaneous effect of vertical wind shear vws and low level mean flow lmf on tropical cyclone tc structure evolution the structural evolution of 180 wester

a heat generation model for continental crust based on deep drilling in the baltic shield abstract this paper presents a heat generation model for the old continental crust on the basis of a new petrological model on the origin evolution and deep structure of the crust in which petrological geochemical and geophysical data obtained from the kola superdeep borehole and other deep boreholes drilled into the crystalline basement of the east european platform are taken into account the petrological section obtained from the borehole observations was extrapolated down to the moho boundary taking into consideration the evolution and generalized seismic model of the continental crust in our model the continental crust is subdivided into three layers a granite gneiss layer 0 17 km a charnokite enderbite layer 17 30 km and a basic layer including autochthonous restites of the protocrust 30 40 km the boundaries between the layers correspond to seismic surfaces k1 and k2 the crustal contribution to heat flow is estimated to be about 25 mw m2 52 of the total heat flow for the baltic shield and the mantle heat flow is 22 24 mw m2 a comparison is made between the heat generation model obtained in this study and the ones estimated from seismic velocity structure the difference in the heat generation value between these models may originate from the differing geological and tectonic history of the sampling localities

the formation of moist vortices and tropical cyclones in idealized simulations abstractthe upscale aggregation of convection is used to understand the emergence of rotating coherent midtropospheric structures and the subsequent process of tropical cyclone formation the cloud model version 1 cm1 is integrated on an f plane with uniform sea surface temperature sst and prescribed uniform background flow deep convection is maintained by surface fluxes from an ocean with uniform surface temperature convection begins to organize simultaneously into moist and dry midtropospheric patches after 10 days after 20 days the patches begin to rotate on relatively small scales moist cyclonic vortices merge eventually forming a single dominant vortex that subsequently forms a tropical cyclone on a realistic time scale of about 5 days radiation that interacts with clouds and water vapor aids in forming coherent rotating structures using the path to genesis provided by the aggregated solution the relationship between thermodynamic changes within the vortex and changes in the character

vertical distribution of heat production in the continental crust abstract using an experimentally established formula seismic velocity vp was converted to heat production a to investigate the vertical distribution of heat sources the conversion performed for a number of characteristic 1 d seismic crustal sections from various tectonic units in central europe yields a general decrease of a with depth z the pattern of decrease depends on geological age young tectonic units with high heat flow exhibit a more rapid decrease the depth dependence of a does not exactly follow the simple exponential law a z a 0 exp z d in general the logarithmic decrement d decreases with depth from 20 30 km at a depth of 10 km to about 10 km at the base of the crust in the uppermost 10 km layer of the crust a certain redistribution of u and th can occur by deep groundwater migration through microcrack networks at depths greater than 10 km geochemical constraints fairly constant th u and k u ratios suggest that the rate of decrease of the heat producing radioelements u th and k is similar

a statistical analysis of the effects of vertical wind shear on tropical cyclone intensity change over the western north pacific abstractthe effect of vertical wind shear vws between different pressure levels on tc intensity change is statistically analyzed based on the best track data of tropical cyclones tcs in the western north pacific wnp from the joint typhoon warning center jtwc and the ecmwf interim reanalysis era interim data during 1981 2013 results show that the commonly used vws measure between 200 and 850 hpa is less representative of the attenuating deep layer shear effect than that between 300 and 1000 hpa moreover the authors find that the low level shear between 850 or 700 and 1000 hpa is more negatively correlated with tc intensity change than any deep layer shear during the active typhoon season whereas deep layer shear turns out to be more influential than low level shear during the remaining less active seasons further analysis covering all seasons exhibits that a tc has a better chance to intensify than to decay when the deep layer shear is lower than 7 9 m s 1 and the low level shear is below

thermophysical parameters and lithospheric thermal structure in guide basin northeast qinghai tibet plateau comprehensive knowledge in lithospheric thermal structure and subsurface temperature distribution is indispensable for the research and utilization of geothermal resources this paper studies the characteristics of heat generation rate and heat conductivity of shallow rocks and deep rocks encompassing guide basin by sampling measuring data collection and analysis establishes the conceptual model of its lithospheric thermal structure the research shows that the mantle heat flow of guide basin is about 35 mw m2 and the ratio of crust heat flow to mantle heat flow is 1 2 with the one dimensional steady state thermal conduction formula the temperature at different depth is calculated in the research area ground temperature at the depth of 1 5 and 3 km is about 72 and 115 c respectively the depth of curie surface is about 21 22 5 km with the temperature of 570 600 c and the temperature of moho is about 1100 c most of the analysis results above are consistent with previous research findings in the research area and its vicinities proving the reasonability of the lithospheric thermal structure model established by this paper as the geothermal research of guide basin still stays at a low level the conceptual model of lithospheric thermal structure in guide basin established in this paper still needs to be improved and corrected with new methods and data in further study

deep geothermal structure and mantle heat flow along the barents sea east alps geotraverse the deep geothermal structure of the continental crust along the barents sea eastern alps profile is investigated numerical geothermal models are constructed the mantle heat flows and the moho temperatures are computed for different tectonic blocks of the crust within ancient platform areas the mantle heat flow varies from 15 28 mw m 2 in the baltic shield to 6 14 mw m 2 in the stable russian plate in the baltic syncline the mantle heat flow is about 25 33 mw m 2 the maximum mantle heat flow value of 40 m w m 2 characterizes the central european platform mantle heat flow values vary from 15 to 35 mw m 2 in the hercynian part of central europe for the thermal model the seismic velocity data are used the moho temperature values vary from 400 c in the ancient platform area to 900 1000 c in the alpine zone in the northern baltic shield tm 600 c

role of the tectonic accretion channel in collisional orogeny high pressure relics studied in many collisional mountain belts are overprinted by subsequent barrovian metamorphism that may reach migmatite grade in the central parts of such orogens we propose that this evolution is linked to the development of a narrow tectonic accretion channel tac at the subducting plate boundary geologic evidence from the southern steep belt of the central alps and the tectono metamorphic record of this orogen guided us in constructing numerical models of a tac simulations indicate that the accretion of crust enriched in radioactive elements to mantle depth provides a mechanism to obtain p t t pressure temperature time trajectories in reasonable agreement with observations in the alps similarly the generation of granitoid melts predicted by the model during late orogenic exhumation of the tac is in line with the alpine record this case study suggests that accretion of upper crust fragments to mantle depth by underplating along a subduction fault and subsequent extrusion of parts of the tac along that same fault may be fundamental processes in the dynamic evolution of many collisional orogens

spatial distribution of gas hydrates from high resolution seismic and core data woolsey mound northern gulf of mexico abstract integration of new jumbo piston cores with high resolution seismic reflection data provides the first documentation on the subsurface distribution of gas hydrates at a deep water cold seep the study area woolsey mound is a carbonate hydrate mound of thermogenic origin in the northern gulf of mexico where salt tectonics dominate the regional structure two typologies of unconventional seismo acoustic data were used in this study 1 surface source deep receiver ssdr data and 2 auv borne chirp sub bottom profiler data correlation of the coring results with seismic interpretations supports the hypothesis that distinctive seismic brightening high frequency scattering present in the ssdr records may indicate the presence of solid hydrates this suggests that such unconventional seismic survey may be prospective for mapping gas hydrates in complex deep water settings coring results revealed the nature of the shallow gas hydrate system to be dominated by fine grained sediments gas hydrates were found exclusively in fracture porosity in the vicinity of a major active fault we present a model for woolsey mound where shallow gas hydrates are systematically distributed along segments of faults intersected by transit of thermogenic hydrocarbons this dual nature of the faults being both gas hydrate reservoirs and gas migration routes suggests a very dynamic hydrate stability field for this site

near bottom turbulence measurements in a partially mixed estuary turbulent energy balance velocity structure and along channel momentum balance abstract a set of moored bottom mounted and shipboard measurements obtained in a straight section of the lower hudson estuary during late summer and early fall of 1995 determine velocity density and along channel pressure gradient throughout the 15 m water column as well as providing direct eddy correlation estimates of reynolds stress and indirect inertial range estimates of dissipation within 3 m of the bottom the analysis focuses on testing 1 a simplified turbulent kinetic energy equation in which production balances dissipation 2 the prandtl karman law of the wall which is a relationship between bottom stress and near bottom velocity gradient and 3 a simplified depth integrated along channel momentum balance involving local acceleration pressure gradient and bottom stress estimates of production and dissipation agree well throughout the entire record the relationship between bottom stress and velocity gradient is consistent with the law of the wall within approximately 1 m of the sea

is there a relationship between seismic velocity and heat production for crustal rocks abstract several investigators proposed an empirical relationship between heat production and seismic velocity for rocks typical of the continental crust these relationships could allow for indirect resolution of the distribution of heat producing elements with depth new heat production data for rock samples from the pikwitonei granulite domain and the sachigo granite greenstone subprovince of the superior province do not follow these relationships indicating that heat production cannot be reliably predicted from seismic velocity these two parameters are not likely to be related as velocity depends upon the major mineral constituents of rocks whereas heat production results from radiogenic components concentrated in both major and trace minerals in rocks

microbial activity in surficial sediments overlying acoustic wipeout zones at a gulf of mexico cold seep 1 down core concentration gradients of dissolved methane and sulfate isotope gradients of methane dissolved inorganic carbon and authigenic carbonate and organic matter elemental ratios are incorporated into a vent evolution model to describe spatial and temporal variability of sedimentary microbial activity overlying acoustic wipeout zones at mississippi canyon mc 118 gulf of mexico we tested the hypothesis that these zones indicate areas where sediments are exposed to elevated fluid flux and therefore should contain saturated methane concentrations and enhanced microbial activity from sulfate reduction sr anaerobic oxidation of methane aom and methanogenesis mp thirty surficial cores between 22 and 460 cm deep were collected from sediments overlying and outside the wipeout zones and analyzed for pore water and solid phase constituents outside the wipeout zones sulfate and methane concentrations were similar to overlying water values and did not vary with depth indicating low microbial activity above the wipeouts nine cores showed moderate activity with gently sloping sulfate and methane concentration gradients methane concentrations 20 m and isotope depth gradients indicative of organic matter oxidation in stark contrast to this moderate activity four cores showed high microbial activity where sulfate concentrations were depleted by 50 cm below seafloor maximum methane concentrations in the decompressed cores were above 4 mm and down core profiles of 13c ch4 and 13c dissolved inorganic carbon dic indicated distinct depth zones of sr aom and mp bulk organic matter analysis suggested that the high activity was supported by an organic source that was enriched in carbon c n 15 and depleted in 15n and 13c compared to other activity groups possibly due to the influx of petroleum or chemosynthetically fixed carbon within high activity cores the 13c dic values were similar to the 13c caco3 values a result expected for authigenic carbonate recently precipitated however these values were dissimilar in moderate activity cores suggesting that microbial activity was higher in the past this study provides evidence that the fluid flux at mc 118 varies over time and that the microbial activity responds to such variability it also suggests that sediments overlying wipeout zones are not always saturated with respect to methane which has implications for the formation and detection of gas hydrate

temporal variability of in situ methane concentrations in gas hydrate bearing sediments near bullseye vent northern cascadia margin 1 to assess the temporal variability in the methane fluxes from marine sediments that overly gas hydrate bearing sediments and the factors that might control its rate in situ methane concentrations were measured near bullseye vent on the northern cascadia continental margin a long term sampling device collected overlying water and pore fluid samples from 25 cm above seafloor at the sediment water interface swi and 7 cmbsf centimeters below seafloor over a 9 month period august 2009 may 2010 these samples provide a record at 4 day resolution of in situ methane ethane propane sulfate and chloride concentrations as well as stable carbon isotope ratios of methane 13c ch4 and dissolved inorganic carbon 13c dic we show that pore fluids near the swi are saturated or supersaturated with respect to methane 80 mm and the methane flux from the seabed is variable over time we hypothesized that regional seismic activity controlled this variable ch4 flux in the northern cascadia continental margin setting however we found no direct correlation between earthquakes and ch4 flux we also posited alternative controls on ch4 flux variability such as storms regional oceanography and microbial activity again no direct correlation was seen this study takes first steps toward exploring which physical factors play a role in methane flux from hydrate bearing sediments

relationship between seismic velocity and heat production comparison of two sets of data and test of validity abstract an empirical relationship between compressional wave velocity v p and radiogenic heat generation a is frequently used to estimate heat production distributions in the continental crust two data sets from rybach and buntebarth 1 and kern and siegesmund 2 have been re evaluated and made comparable bulk density was included as a further parameter to investigate the relationships v p a v p and a statistical analysis shows reasonably high and comparable regression coefficients for the first two relationships but much less agreement for the a relationship

fluid genesis through serpentinites and the origin of subsurface electrical conductors in northwest india and adjoining regions abstract large scale conductivity anomalies have been detected and subsequently modelled inverted based on the data of geomagnetic deep sounding in northwest india by various researchers in this study by analytical dissection of several other geophysical parameters in conjunction with the constrained modelling of electrical parameters of the conductors we believe that we have resolved the origin of three northwest indian conductors this issue had remained so far either speculative or an explanation was given without taking due analytical support from other geophysical data moreover a unique relationship has been found and the same advocated amongst the high values of poisson s ratio and the electrical parameters of conductors these high values of poisson s ratio conform to the presence of serpentinites in the region at appropriate depths under the present geotectonic setting the upward migration of serpentine from mantle to subcrustal level and its consequent dehydration leading to fluid genesis seems to be the appropriate cause for the conductivity anomalies in the northwest indian region including lesser himalaya however the exact mechanism for upward migration a fact established elsewhere may at present remain tentative some indirect inferences have been drawn through a hypothesized model cartoon to shed light on the possible mode of fluid transport resulting in conductivity anomalies of the region the presence of fluids has also been cited in literature in higher himalayan regions resulting due to under thrusting of the indian basement elsewhere in the northwest himalayan region the presence of serpentinite in close association of eclogite has been found these serpentinites are formed by hydration of the mantle wedge resulting due to de watering of the subducted slab these facts strengthen the belief of the continuation of fluid body in himalayan and adjacent northwest region in the crust

ocean circulation promotes methane release from gas hydrate outcrops at the neptune canada barkley canyon node 1 the neptune canada cabled observatory network enables non destructive controlled experiments and time series observations with mobile robots on gas hydrates and benthic community structure on a small plateau of about 1 km2 at a water depth of 870 m in barkley canyon about 100 km offshore vancouver island british columbia a mobile internet operated vehicle was used as an instrument platform to monitor and study up to 2000 m2of sediment surface in real time in 2010 the first mission of the robot was to investigate the importance of oscillatory deep ocean currents on methane release at continental margins previously other experimental studies have indicated that methane release from gas hydrate outcrops is diffusion controlled and should be much higher than seepage from buried hydrate in semipermeable sediments our results show that periods of enhanced bottom currents associated with diurnal shelf waves internal semidiurnal tides and also wind generated near inertial motions can modulate methane seepage flow dependent destruction of gas hydrates within the hydrate stability field is possible from enhanced bottom currents when hydrates are not covered by either seafloor biota or sediments the calculated seepage varied between 40 400 mol ch4 m 2 s 1 this is 1 3 orders of magnitude higher than dissolution rates of buried hydrates through permeable sediments and well within the experimentally derived range for exposed gas hydrates under different hydrodynamic boundary conditions we conclude that submarine canyons which display high hydrodynamic activity can become key areas of enhanced seepage as a result of emerging weather patterns due to climate change

subinertial slope trapped waves in the northeastern gulf of mexico abstract current velocity from moored arrays of acoustic doppler current profilers adcps deployed on the outer shelf and slope south of mobile bay in the northeastern gulf of mexico shows evidence of alongslope generally westward propagating subinertial baroclinic kelvin waves with periods of about 16 and 21 days amplitudes of 5 10 cm s 1 and wavelengths of about 500 km the observed waves were highly coherent over the slope between about 200 and 500 m and accounted for a significant amount of the current variability below 200 m the source of the waves could be attributed to effects of the loop current on the west florida slope but is more likely due to direct forcing by loop current generated eddies impacting the experimental area

heat generating radioelements in granitic magmas abstract spatial variation trends of the radioelements u th and k in granitic units show distinct regularities zonation patterns of u and th at fairly constant k contents are common in individual granitic bodies it is shown that radioelement abundance and distribution result from a combined migration diffusion process in the fluid phase during and after solidification of the granite magma the process is mainly governed by pressure and temperature gradients as well as by chemical potentials model calculations yield numerical values for the intrinsic diffusion coefficient 10 4 cm 2 s and migration velocity 0 2 2 cm s which are in agreement with laboratory experiments on comparable systems the process distributing the radioelements is of limited duration it is also clearly related to the cooling history of the granite analogies to the overall distribution of crustal radioactivity are discussed

the use of cation packing index for characterizing the weathering degree of granitic rocks the weathering state and weatherability of rocks are highly important for engineering geology projects and the use of rocks as building stones the weathering state of rocks can be described by various chemical and petrographical weathering indices to determine weathering state of a rock considerable amount of chemical analyses is required weatherability of rocks depends on not only their mineral composition but also the number of cation replaceable with hydrogen in a mineral in this study the use of the k value cation packing index is defined as the number of cation in a mole for characterizing the degree of weathering of granitic rocks is investigated for the purpose of the study the kurtun granitic rocks are selected as the material of the study the study contains three main stages and these are field investigations laboratory studies and regression analyses during the field studies in situ weathering descriptions and sampling are carried out the samples are subjected to chemical and petrographic analyses and physical and mechanical tests at the final stage of the study a series of regression analyses between the cation packing index and other properties of the samples are performed the results show that the k value can be used as a weathering indicator when compared with the other chemical weathering indices the k value can be used as a weathering index without chemical analyses because it can be determined by mineralogical analyses

the ventilation of the deep gulf of mexico abstract recent measurements over the sill in the yucatan channel indicate that the deepest flows between the caribbean sea and the gulf of mexico those that take place below the sill level at the florida straits have zero mean net mass transport but carry significant amounts of heat and oxygen the heat flux associated with the mean exchange exports approximately 150 gw from the deep gulf toward the caribbean and may be related to the formation of the yucatan undercurrent the eddy heat transfer is also significantly different from zero and exports on average an additional 60 gw this eddy transfer is attributable mostly to events that last from a few days to about 1 5 months during which colder water from deeper levels in the caribbean beneath 2000 m flows over the sill within a bottom boundary layer close to 200 m thick the colder water is also very rich in oxygen and the deep exchange sustains the near bottom oxygen maximum in the gulf of mexico whence that cold water must slide down the north

density temperature and rheological models for the southeastern canadian cordillera implications for its geodynamic evolution two dimensional density temperature and rheological models are constructed for a 350 km northeast trending transect of the southeastern canadian cordillera all models highlight several major physical differences between foreland and hinterland lithosphere significant features of the density model are the presence of an anomalously low density 3 10 103 kg m 3 layer with a maximum thickness of 12 km beneath the moho in the hinterland the similar densities of the monashee terrane and the cratonic crust of the foreland and an increase in crustal thickness beneath the southern rocky mountain trench the temperature model shows steeper gradients and higher moho temperatures beneath the hinterland than beneath the foreland in the rheological model the hinterland is characterized by a thin brittle upper crust beneath which the entire lithosphere is hot weak and ductile in contrast the foreland is composed of a thick brittle upper crust with an additional brittle zone in the upper mantle the

heat production and seismic velocity of crustal rocks heat production of the continental crust can be determined from the seismic velocity structure there is however a significant scatter in the determination partly caused by the quality of geothermal data and partly by the fact that seismic velocity and radiogenic heat production are not uniquely related to each other by the chemical composition of rocks

density and seismic velocity in relation to mineralogical constitution based on an ionic model for minerals considering silicates and spinels as a close packing of spherical ions the oxygen ions because of their relatively large ionic radius use up more than 90 of the total ionic volume the close packing of oxygen forms a framework structure with partially constant physical properties the cations including silicon are small enough to fit into the interstices between the large sized oxygen ions without widening their framework structure the idealized space filling character of the cations explains the variations in physical properties of minerals on the basis of one variable only the cation packing index labeled k value k number of cations per mole avogadro s number s molar volume this variable is used to describe the density as well as the seismic velocity it is shownthat relationships between k value and both density and seismic velocity have approximately a linear character

geothermal profiles of the lithosphere in central asia abstract we present generalized heat flow data and estimated deep temperatures in the lithosphere along two geothermal profiles in central asia geological control along these profiles is provided by boreholes and three seismic reflection profiles the 1200 c isotherm is estimated to be at depths of 180 200 km in the southern part of the siberian platform the depth of this isotherm decreases to 120 150 km in the trans baikal area and to 60 80 km in the baikal rift zone

observations of the structure and evolution of hurricane edouard 2014 during intensity change part ii kinematic structure and the distribution of deep convection abstractthe structural evolution of the inner core and near environment throughout the life cycle of hurricane edouard 2014 is examined using a synthesis of airborne and satellite measurements this study specifically focuses on differences in the distribution of deep convection during two periods when edouard intensified toward hurricane status and when edouard peaked in intensity and began to weaken while both periods saw precipitation maximized in the downshear left and upshear left quadrants deep convection was only seen from the aircraft during the intensifying period deep convection was located farther inside the radius of maximum winds rmw during the intensifying period than the weakening period this convection is traced to strong updrafts inside the rmw in the downshear right quadrant tied to strong low level convergence and high convective available potential energy cape as the storm remained over warm water in a moist environment strong updrafts persisted upshear left and were collo

linear relationships between petrophysical properties and mineralogical constitution preliminary results abstract a direct way for tightly relating the mineralogical constitution to density and seismic velocity is demonstrated in an attempt to characterize rocks by a single quantity the oxygen ions are considered as a closely packed structure thus the distribution of cations including silicon ought to correlate with the density as well as with the seismic velocity the cation fraction for each mineral phase is defined by the value the ratio of the number of cations per mole to the molar volume normalized by avogadro s number it is shown experimentally that linear relationships exist between the value and both density and seismic velocity

one dimensional thermal modeling of the eastern pontides orogenic belt ne turkey the eastern pontides orogenic belt is one of the most complex geodynamic settings in the alpine himalayan belt due to the lack of systematical geological and geophysical data in this study 1d crustal structure and p wave velocity distribution obtained from gravity modeling and seismological data in the area has been used for the development of the thermal model of the eastern pontides orogenic belt the computed temperature depth profiles suggest a temperature of 590 60 c at a moho depth of 35 km indicates the presence of a brittle ductile transition zone this temperature value might be related to water in the subducted crust of the tethys oceanic lithosphere the curie temperature depth value of 29 km which may correspond to the crustal magma chambers is found 5 7 km below the moho depth surface heat flow density values vary from 66 5 and 104 7 mw m 2 high mantle heat flow density value of 48 mw m 2 is obtained for the area should be related to melting of the lithospheric mantle caused by upwelling of asthenosphere

a test of the relationship between seismic velocity and heat production for crustal rocks new heat production data of 40 rock samples comprising a wide variety of crustal rocks are compared with respective p wave velocities and densities in order to test the empirical velocity density heat production systematics proposed by rybach and buntebarth 1 2 which have been used by several investigators to determine heat production with depth in the crust our laboratory data do not convincingly fit any of the proposed relationships the lack of confirmation is attributed to the fact that the physical rock properties are mainly related to the single crystal properties of the respective major minerals whereas heat production in the rocks results from radiogenic components which are largely concentrated in accessory minerals

two dimensional inverse modeling of crustal thermal regime with application to east european geotraverses the modeling of crustal thermal regimes is basically the inference of subsurface distributions of heat flow density and temperature by continuing downward the near surface measurements of heat flow density temperature thermal conductivity and heat production to account for the uncertainties in the near surface data and in the subsurface distributions of thermal conductivity and heat production and to provide explicit estimates for the uncertainties in the resulting models we have employed a bayesian inverse formulation that incorporates the a priori information on model parameters in the form of a joint gaussian probability density function and that gives the inverse solution in the form of the most probable estimates and the a posteriori covariance matrix for the model parameters to illustrate the method we apply it to the modeling of thermal regimes along east european geotraverses eegt 5 and eegt 1 using both a linear 5 point finite difference and a quadrilateral isoparametric finite element discretization two features are emphasized first we introduce an a priori autocovariance function for the heat flow density at model base to help stabilize the solution second we demonstrate the improvement in solution accuracy and resolution when a priori temperature information is available and incorporated in the inversion for the geotraverses studied the finite difference and finite element formulations yield essentially identical results although there is a substantial difference in the extent of their parameterization in general the surface and basal heat flow densities are similar in shape implying a relatively uniform total crustal heat production across the geotraverses both the heat flow densities and the crustal temperatures exhibit strong lateral variations that appear to correlate with the tectonic age the heat flow densities and temperatures are low in the precambrian east european platform relatively higher in the variscan units high in the alps and very high in the pannonian basin the results support the presence of lateral variations of up to 40 m w m 2 in the moho heat flow density provided that one accepts as reasonable an a priori standard deviation of 25 for the surface heat flow density and an uncertainty of a factor of two for the heat production finally the a posteriori and the observed surface heat flow densities match well but exceptions occur in localized regions suggesting the presence of perturbing effects that cannot be accounted for in a steady state purely conductive model

isentropic analysis on the intensification of hurricane edouard 2014 abstractan isentropic analysis technique is adopted in this study to investigate the intensification of hurricane edouard 2014 predicted by an experimental real time convection permitting hurricane analysis and forecast system this technique separates the vertical mass transport in terms of equivalent potential temperature e for the rising air parcels at high entropy from the subsiding air at low entropy it is found that as edouard intensifies the vertical circulation becomes wider via the expansion of upward downward mass flux to higher lower e in the early developing stages the asymmetric convection dominates the vertical circulation and leads to a remarkable upward mass flux maximum center in the upper troposphere when edouard becomes intense the axisymmetric convection becomes important to the upper level vertical mass transport while the asymmetric convection still dominates the low level vertical mass transport development of the warm core in the eye leads to double maxima along the

a heat production model of the crust and upper mantle abstract experimental evidence on the relationship between seismic velocity and radiogenic heat production has been used to estimate the vertical distribution of heat sources in the continental lithosphere the derived differentiation rate of the radioelements with depth has been investigated to depths 100 km in various world wide tectonic provinces the results show that more pronounced upward differentiation steeper heat production distribution corresponds to regions of higher heat flow and usually higher crustal temperatures thus crustal distributions of radiogenic heat may be related to tectonic age and crustal evolution the vertical distribution of heat production can be traced even in the subcrustal lithosphere and confirms the upward concentration of a substantial part of the radioelements into the crust at the expense of the upper mantle reflecting the early stages of crustal separation while in the uppermost crust the distribution of the heat sources seems to be controlled by uranium and thorium in the upper mantle it is potassium which controls it data obtained may be important in the geothermal modelling deep temperature calculation and in determinations of moho heat flow

heat flow heat production and granite depth in western france newly measured heat flow and full heat production determinations over the armorican massif western france are tested against a linear relationship as proposed through birch s law the data do not fit a strict linear relationship but are within an elongated cluster which can be approximated in mw m and km by these parameters are compared with those of surrounding hercynian regions data from the central massif and previously failed to fit any linear relationship data for scotland and southern england could not be fitted to a single line however the present data and those from southern and central england do fit a single line suggesting that the three regions form a single geothermal province the depth parameter is greater than the root depths of the granitic plutons indicating that heat sources can exist at depths below the granitic intrusions the deep crustal structure revealed from seismic studies agrees with the radiogenic elements distribution deduced from thermal data

a model for temperature variations in sedimentary basins due to random radiogenic heat sources summary the thermal structure of a sedimentary basin is controlled by its thermal conductivity its boundary conditions water flow rate of sedimentation and erosion and radiogenic heat sources the radiogenic heat production in the sediments is known to vary over several orders of magnitude with the lowest values in evaporites and carbonates and the highest values in black shales due to a paucity of information available on the existing heat sources this parameter can be represented with a known mean value and a gaussian correlation structure rather than a deterministic function in this paper the 1 d steady state thermal structure in a sedimentary basin has been modelled in a stochastic framework with a random radiogenic heat source and analytical expressions for the first two moments of the temperature field have been obtained a synthetic example has been examined to quantify the error bounds on the temperature field due to uncertainties in the radiogenic heat sources

thermo rheological structure of the northern margin of the south china sea structural and geodynamic implications abstract rheological properties of continental lithosphere are key controls on the behavior of continental deformation using thermal structure constrained by surface heat flow data and measured thermal properties of rocks the present study calculates different thermo rheological structure scenarios for the ocean continent transition oct at the northern margin of the south china sea using two different models a conventional model taking into account frictional sliding and power law creep and a model that additionally includes a high pressure brittle fracture mechanism two compositions of the lower part of the lithosphere are considered a soft case with felsic granulite lower crust and wet peridotite lithospheric mantle and a hard case with mafic granulite lower crust and dry peridotite lithospheric mantle the former scenario shows a major rheological change from a jelly sandwich to a christmas tree type of rheology from north to south along the margin this complex rheological structure explains lateral changes in earthquake distribution and geometries of extensional faults of the oct at the northern margin of the south china sea further our analyses indicate that the initial lithospheric rheology profile probably has only one ductile layer in the lower part of upper crust such an initial lithospheric rheology model predicts focused extension to form asymmetric margins which is the case for the scs

sustained in situ measurements of dissolved oxygen methane and water transport processes in the benthic boundary layer at mc118 northern gulf of mexico abstract within months of the bp macondo wellhead blowout elevated methane concentrations within the water column revealed a significant retention of light hydrocarbons in deep waters plus corresponding dissolved oxygen do deficits however chemical plume tracking efforts were hindered by a lack of in situ monitoring capabilities here we describe results from in situ time series lander based investigations of physical and biogeochemical processes controlling dissolved oxygen and methane at mississippi canyon lease block 118 18 km from the oil spill conducted shortly after the blowout through april 2012 multiple sensor arrays plus open cylinder flux chambers chimneys deployed from a benthic lander collected oxygen methane pressure and current speed and direction data within one meter of the seafloor the rovard lander system was deployed for an initial 21 day test experiment 9 13 2010 10 04 2010 at 882 m depth before a longer 160 day deployment 10 24 2011 4 01 2012 at 884 m depth temporal variability in current directions and velocities and water temperatures revealed strong influences of bathymetrically steered currents and overlying along shelf flows on local and regional water transport processes do concentrations and temperature were inversely correlated as a result of water mass mixing processes flux chamber measurements during the 160 day deployment revealed total oxygen utilization tou averaging 11 6 mmol m2 day chimney do concentrations measured during the 21 day deployment exhibited quasi daily variations apparently resulting from an interaction between near inertial waves and the steep topography of an elevated scarp immediately adjacent to the 21 day deployment site that modulated currents at the top of the chimney variability in dissolved methane concentrations suggested significant temporal variability in gas release from nearby hydrocarbon seeps and or delivery by local water transport processes free vehicle lander monitoring over time scales of months to years utilizing in situ sensors can provide an understanding of processes controlling water transport respiration and the fate and impacts of accidental and natural gas and oil releases

regional heat flow in western anatolia using silica temperature estimates from thermal springs regional trends of variation of heat flow in western anatolia have been outlined using the silica temperature estimator on thermal springs silica heat flow values from 187 springs have been calculated the data are corrected for local long term mean annual surface temperature a mean value of heat flow for the western part of anatolia of 107 45 mw m 2 has been obtained which is about 60 above the world average the silica heat flow data are compared with available conventional heat flow values for this region a general agreement is observed and new patterns are recognized a close association exists between areas of high silica heat flow values above 100 mw m 2 and areas of tertiary and younger volcanism high heat flow is also observed in palaeozoic units of the menderes massif which is under tensional stress the highest heat flow estimate of 247 mw m 2 is obtained near gediz 38 57 n 29 13 2 e this area is part of a seismically active region and is located near a middle eocene subduction zone which is an area of later collision tectonics the new heat flow data from western anatolia improve our knowledge of the thermal conditions within the crust this information is important for the analysis of various geophysical and geological phenomena including seismicity

radiogenic heat production in the lithosphere of sulu ultrahigh pressure metamorphic belt abstract the chinese continental scientific drilling ccsd project is located at the sulu ultrahigh pressure metamorphic uhpm belt it offers a unique opportunity for studying the radiogenic heat production of both shallower and deeper rocks based on the concentrations of radiogenic elements u th and k on 349 samples from main hole of ccsd ccsd mh pilot holes and exposures we determined radiogenic heat productions of all major rock types in the sulu uhpm belt results show the mean values of orthogneiss and paragneiss are respectively 1 65 0 81 and 1 24 0 61 w m 3 due to different composition and grade of retrogressive metamorphism the eclogites display significant scatter in radiogenic heat production ranging from 0 01 to 2 85 w m 3 with a mean of 0 44 0 55 w m 3 the radiogenic heat production in ultramafic rocks also varies within a large range of 0 02 to 1 76 w m 3 and the average turns out to be 0 18 0 31 w m 3 based on the measurements and crustal petrologic model the vertical distribution model of heat production in sulu crust is established the resulting mean heat production 0 76 w m 3 contributes 24 mw m 2 to the surface heat flow 1 d thermal model indicates that the temperature at the moho reaches above 750 c and the thermal thickness of the lithosphere is 75 km in good agreement with the geophysical results the high teat flow 75 mw m 2 together with thin lithosphere presents strong support for the extension events during the late cretaceous and cenozoic

a numerical study on rapid intensification of typhoon vicente 2012 in the south china sea part ii roles of inner core processes abstractin part i of this study the role of environmental monsoon flow in the onset of rapid intensification ri of typhoon vicente 2012 was discussed in this part ii key inner core processes that effectively resist environmental vertical wind shear during ri onset are investigated the convective precipitation shield cps embedded in the downshear convergence zone plays a vital role in preconditioning the tropical cyclone tc vortex before ri the cps induces a mesoscale positive vorticity band pvb characterized by vortical hot tower structures upstream and shallower structures 4 km downstream multiple mesovortices form successively along the pvb and are detached from the pvb at its downstream end rotating cyclonically around the tc center the sufficient amount of vorticity anomalies in the pvb facilitates the upscale growth of a mesovortex into a reformed inner vortex which eventually replaces the parent tc vortex i e downshear reformation leading to ri onset the timing of downshe

property distributions and deep chemical measurements within the western gulf of mexico distribution of salinity dissolved oxygen nitrate phosphate and silicate are presented for the western gulf of mexico in 1978 plots of chemical concentration versus potential density are used to identify the presence of gulf water tropical atlantic central water antarctic intermediate water caribbean midwater and upper north atlantic deep water within the upper 1600 m of the western gulf of mexico property distributions are closely related to the current regime described by merrell and morrison 1981 also we present values for tritium carbon 14 radium 226 and radon 222 that were taken at a deep station located at 23 02 n and 92 28 w

quadrant dependent evolution of low level tangential wind of a tropical cyclone in the shear flow abstractthis study investigates the quadrant by quadrant evolution of the low level tangential wind near the eyewall of an idealized simulated mature tropical cyclone embedded in a unidirectional shear flow it is found that the quadrant averaged tangential wind in the right of shear quadrants weakens continuously while that in the left of shear quadrants experiences a two stage evolution a quasi steady stage followed by a weakening stage after the imposing of vertical wind shear this leads to a larger weakening rate in the right of shear and a stronger jet in the left of shear quadrants the budget analysis shows that the quadrant dependent evolution of tangential wind is controlled through the balance between the generalized coriolis force gcf i e the radial advection of absolute angular momentum and the advection terms the steady decreasing of the gcf is primarily responsible for the continuous weakening of jet strength in the right of shear quadrants for the left of shear quadrants the quas

heat sources heat transfer and rock types in the lower continental crust inference from deep drilling abstract structures properties and processes below the final depth of deep drilling dd represent important research targets looking ahead of the bit it is shown how to derive the distribution of radioactive heat sources the predominant heat transfer mechanism the temperature field and an estimate about the petrologic nature of the crustal realm in question i e between the dd bottom hole and the moho large parts of the input data needed for these derivations can be acquired during dd site characterization and or during dd opeations the outlined procedures lead to specific requirements for deep drilling sites

distribution of radioactive heat production around an active fault and in accretionary prisms of southwest japan abstract contents of radioactive heat producing elements u th and k were measured on core samples from a borehole drilled into the shear zone of the active nojima fault southwest japan the heat production rate is rather uniform in a granite layer below 560 m with an average of 1 6 w m 3 in the lower part of the granite layer which is close to the fault zone the u th and u k ratios seem to be lower than those in the upper part a possible cause of this anomaly is redistribution of u by groundwater flows in highly fractured layers through monitoring of the temperature profile in the borehole a local anomaly which may be associated with groundwater flow along a fracture zone was detected in the uppermost part of the hole the conductive heat flow was found to increase with depth which is possibly due to downward fluid flow in the surrounding formations measurements of heat production were also made on rock samples from permian to cretaceous accretionary prisms in southwest japan the heat production of sandstone and mudstone major components of the accretionary prisms is about 1 5 w m 3 on average which is similar to the average value for granitic rocks in southwest japan these values are significantly higher than those reported in accreted terranes in the cascadia subduction zone

gamma ray spectrometry in the field radioactive heat production in the central slovakian volcanic zone we report 62 sets of measurements from central southern slovakia obtained using a modern portable gamma ray spectrometer which reveal the radioactive heat production in intrusive and extrusive igneous rocks of the late cenozoic central slovakian volcanic zone sites in granodiorite of the stiavnica pluton are thus shown to have heat production in the range 2 2 4 9 w m 3 this variability being primarily a reflection of variations in content of the trace element uranium sites in dioritic parts of this pluton have a lower but overlapping range of values 2 1 4 4 w m 3 sites that have been interpreted in adjoining minor dioritic intrusions of similar age have heat production in the range 1 4 3 3 w m 3 the main stiavnica pluton has zoned composition with potassium and uranium content and radioactive heat production typically increasing inward from its margins reflecting variations observed in other granodioritic plutons elsewhere it is indeed possible that the adjoining dioritic rocks hitherto assigned to other minor intrusions of similar age located around the periphery of the stiavnica pluton in reality provide further evidence for zonation of the same pluton the vicinity of this pluton is associated with surface heat flow 40 mw m 2 above the regional background on the basis of our heat production measurements we thus infer that the pluton has a substantial vertical extent our preferred estimate for the scale depth for its downward decrease in radioactive heat production being 8 km nonetheless this pluton lacks any significant negative bouguer gravity anomaly we attribute this to the effect of the surrounding volcanic caldera filled with relatively low density lavas masking the pluton s own gravity anomaly we envisage that emplacement occurred when the pluton was much hotter and thus of lower density than at present its continued uplift evident from the local geomorphology being the isostatic consequence of localized erosion the heat production in this intrusion evidently plays a significant role hitherto unrecognized in the regional geothermics

the convective evolution and rapid intensification of hurricane earl 2010 abstractthe relationship between an inner core r 100 km lightning outbreak and the subsequent rapid intensification ri of hurricane earl 2010 is examined using lightning strikes recorded by the world wide lightning location network wwlln and in situ observations from various aircraft missions moderate 8 4 m s 1 northeasterly deep layer 850 200 hpa vertical wind shear caused by outflow from hurricane danielle existed over earl at the beginning of a prolonged period of ri over 70 of the lightning strikes within a 500 km radius occurred downshear with a preference toward downshear right in the outer rainbands in agreement with previous studies the location of inner core strikes in earl differed markedly from previous studies the inner core lightning activity precessed from left of shear to upshear an extremely rare event beginning just prior to the onset of ri diagnosis of the vortex tilt midway through the lightning precession showed this convection was occurring downtilt in the ups