chloride bearing materials in the southern highlands of mars chlorides commonly precipitate during the evaporation of surface water or groundwater and during volcanic outgassing spectrally distinct surface deposits consistent with chloride bearing materials have been identified and mapped using data from the 2001 mars odyssey thermal emission imaging system these deposits are found throughout regions of low albedo in the southern highlands of mars geomorphologic evidence from orbiting imagery reveals these deposits to be light toned relative to their surroundings and to be polygonally fractured the deposits are small

flowgo a kinematic thermo rheological model for lava flowing in a channel we present a kinematic self adaptive numerical model to describe the down flow thermal and rheological evolution of channel contained lava as our control volume of lava advances down a channel it cools and crystallizes an increasingly thick and extensive surface crust grows and its heat budget and rheology evolve by estimating down flow heat and velocity loss our model calculates the point at which the control volume becomes stationary giving the maximum distance lava flowing in the channel can extend modeled effusion rates velocities widths surface crust parameters heat budget cooling temperature crystallinity viscosity and yield strength all compare well with field data collected during eruptions at mauna loa k lauea and etna modeled lengths of 25 27 2 5 5 7 and 0 59 0 83 km compare with measured lengths of 25 27 4 and 0 75 km for the three flows respectively over proximal flow portions we calculate cooling crystallization viscosity and yield strength of 1 10 c km 1 0 001 0 01 volume fraction km 1 103 104 pa s and 10 3 102 pa respectively at the flow front cooling crystallization viscosity and yield strength increase to 100 c km 1 0 1 volume fraction km 1 106 107 pa s and 103 104 pa respectively all of which combine to cause the lava to stop flowing our model presents a means of a analyzing lava flow thermo rheological relationships b identifying important factors in determining how far a channel fed flow can extend c assessing lava flow hazard and d reconstructing flow regimes at prehistoric unobserved or remote flows

hydrocarbon generation and expulsion characteristics of eocene source rocks in the huilu area northern pearl river mouth basin south china sea implications for tight oil potential abstract in recent years new oil reservoirs have been discovered in the eocene tight sandstone of the huilu area northern part of the pearl river mouth basin south china sea indicating good prospects for tight oil exploration in the area exploration has shown that the huilu area contains two main sets of source rocks the eocene wenchang e2w and enping e2e formations to satisfy the requirements for further exploration in the huilu area particularly for tight oil in eocene sand reservoirs it is necessary to re examine and analyze the hydrocarbon generation and expulsion characteristics based on mass balance this study investigated the hydrocarbon generation and expulsion characteristics as well as the tight oil resource potential using geological and geochemical data and a modified conceptual model for generation and expulsion the results show that the threshold and peak expulsion of the e2w source rocks are at 0 6 vitrinite reflectance and 0 9 vitrinite reflectance respectively there were five hydrocarbon expulsion centers located in the western eastern and northern huizhou sag and the southern and northern lufeng sag the hydrocarbon yields attributed to e2w source rocks are 2 4 1011 tons and 1 6 1011 tons respectively with an expulsion efficiency of 65 the e2e source rock threshold and peak expulsion are at 0 65 vitrinite reflectance and 0 93 vitrinite reflectance respectively with hydrocarbon expulsion centers located in the centers of the huizhou and lufeng sags the yields attributed to e2e source rocks are 1 1 1011 tons and 0 2 1011 tons respectively with an expulsion efficiency of 20 using an accumulation coefficient of 7 13 the eocene tight reservoirs could contain approximately 1 3 1010 tons to 2 3 1010 tons with an average of 1 8 1010 tons of in place tight oil resources highest recoverable coefficient can reach 17 18 indicating that there is significant tight oil potential in the eocene strata of the huilu area

determining soil moisture and sediment availability at white sands dune field new mexico from apparent thermal inertia data 1 determinations of soil moisture and sediment availability in arid regions are important indicators of local climate variability and the potential for future dust storm events data from the advanced spaceborne thermal emission and reflection aster radiometer were used to derive the relationships among potential soil erosion soil moisture and thermal inertia ti at the spatial scale of aeolian landforms for the white sands dune field between may 2000 and march 2008 land surface apparent thermal inertia ati data were used to derive an approximation of actual ti in order to estimate the wind threshold velocity ratio wtr the wtr is a ratio of the wind velocity thresholds at which soil erosion occurs for wet soil versus dry soil the aster derived soil moisture retrievals and the changes through time at white sands were interpreted to be driven primarily by precipitation but the presence of a perched groundwater table may also influence certain areas the sediment availability of dunes active playa surfaces and the margin of the alluvial fans to the west were determined to be consistently higher than the surrounding area the sediment availability can be primarily explained by precipitation events and the number of dry days prior to the data acquisition other factors such as vegetation and the amount of surface crusting may also influence soil mobility but these were not measured in the field this approach showed the highest modeled sediment availability values just days prior to the largest dust emission event at white sands in decades such an approach could be extended to a global monitoring technique for arid land systems that are prone to dust storms and for other regional land surface studies in the sahara

construction dynamics of a lava channel we use a kinematic gps and laser range finder survey of a 200 m long section of the muliwai a pele lava channel mauna ulu kilauea to examine the construction processes and flow dynamics responsible for the channel levee structure the levees comprise three packages the basal package comprises an 80 150 m wide a a flow in which a 2 m deep and 11 m wide channel became centred this is capped by a second package of thin 45 cm thick sheets of pahoehoe extending no more than 50 m from the channel the upper most package comprises localised a a overflows the channel itself contains two blockages located 130 m apart and composed of levee chunks veneered with overflow lava the channel was emplaced over 50 h spanning 30 may 2 june 1974 with the flow front arriving at our section 4 4 km from the vent 8 h after the eruption began the basal a a flow thickness yields effusion rates of 35 m3 s 1 for the opening phase with the initial flow advancing across the mapped section at 10 m min short lived overflows of fluid pahoehoe then built the levee cap increasing the apparent channel depth to 4 8 m there were at least six pulses at 90 420 m3 s 1 causing overflow of limited extent lasting no more than 5 min brim full flow conditions were thus extremely short lived during a dominant period of below bank flow flow depth was 2 m with an effusion rate of 35 m3 s 1 consistent with the mean output rate obtained from the total flow bulk volume of 23 54 m3 s 1 during pulses levee chunks were plucked and floated down channel to form blockages in a final low effusion rate phase lava ponded behind the lower blockage to form a syn channel pond that fed a a overflow after the end of the eruption the roofed over pond continued to drain through the lower blockage causing the roof to founder drainage emplaced inflated flows on the channel floor below the lower blockage for a further 10 h the complex processes involved in levee channel construction of this short lived case show that care must be taken when using channel dimensions to infer flow dynamics in our case the full channel depth is not exposed instead the channel floor morphology reflects late stage pond filling and drainage rather than true channel contained flow components of the compound levee relate to different flow regimes operating at different times during the eruption and associated with different effusion rates flow dynamics and time scales for example although high effusion rate brim full flow was maintained for a small fraction of the channel lifetime it emplaced a pile of pahoehoe overflow units that account for 60 of the total levee height we show how time varying volume flux is an important parameter in controlling channel construction dynamics because the complex history of lava delivery to a channel system is recorded by the final channel morphology time varying flow dynamics can be determined from the channel morphology developing methods for quantifying detailed flux histories for effusive events from the evidence in outcrop is therefore highly valuable we here achieve this by using high resolution spatial data for a channel system at kilauea this study not only indicates those physical and dynamic characteristics that are typical for basaltic lava flows on hawaiian volcanoes but also a methodology that can be widely applied to effusive basaltic eruptions

what can thermal infrared remote sensing of terrestrial volcanoes tell us about processes past and present on mars over the past fifty years a diverse set of thermal infrared tir remote sensing data has been acquired from the orbits of earth and mars which both have ubiquitous volcanic landforms these data vary in spatial spectral and temporal resolution and are critical for investigating an ever expanding set of science applications including the focus of this review paper volcanic processes volcanic studies using tir data include active monitoring of flows and plumes on earth and mapping the compositional and thermophysical diversity on mars furthermore recent advances in high resolution low cost ground and laboratory tir instrumentation now help to augment the orbital data through a synergistic approach to data analysis and validation field and laboratory studies also serve as terrestrially focused analogues that provide important insights to interpret the geologic processes that have operated on other planetary surfaces including mars this review expands upon our invited talk of the same title at the 2014 geological society of america meeting to include several case studies designed to give the reader an overview of how tir data can be applied to volcanic processes on earth and mars these case studies highlight prior work by the authors presented at past meetings but which have not been published elsewhere the examples were chosen specifically to identify the tir data similarities between the two planets and include analyses of volcanic surfaces to 1 derive composition and texture using tir spectra earth and mars 2 analyze mantled flows with thermophysical data earth and mars 3 estimate lava discharge rate using tir derived temperature earth with application to mars and 4 model flow dynamics based on geomorphic measurements mars because of our focus on the tir we do not attempt to document other remote sensing wavelength regions nor even every volcanic study using tir data as tir instruments have improved over time along similar trajectories the higher spatial and spectral resolutions provide the ability to examine volcanic processes in more quantitative ways despite the fact that no tir instrument has ever been designed solely to study volcanic phenomena whether these trends continue for both planets will depend on the design of new tir technologies the data they produce and the science that results from the data

direct measurements of ocean surface velocity from space interpretation and validation the median doppler shift of radar echoes is analyzed in measurements by envisat s advanced synthetic aperture radar asar over the ocean this doppler centroid differs from a predicted signal based on the predicted motion of the satellite and earth this anomaly converted to a surface doppler velocity u d appears to be of geophysical origin two wide swath images over the gulf stream around cape hatteras suggest that u d contains high resolution information on surface currents while on a global scale u d is found to vary with the wind speed in the range direction a simple quantitative forward model is proposed based on a practical two scale decomposition of the surface geometry and kinematics the model represents the effect of the wind through the wave spectrum and gives u d u 10 u c with u 10 and u c as the 10 m wind speed and quasi eulerian current in the line of sight of the radar projected on the sea surface respectively and as a coefficient function of the wind speed wave development and radar geometry it is found that for an incidence angle of 23 0 3 for moderate winds and fully developed seas this model is validated with a global data set of asar wave mode observations with colocated model winds acquired over the global ocean during the years 2003 and 2004 the doppler signal therefore provides the signed parameter u d that can be used to reduce the wind direction ambiguity in the inversion of high resolution wind fields from sar imagery a qualitative validation of current effects is shown for the english channel where tidal currents dominate thus it should be possible to combine this previously ignored geophysical doppler signal with traditional information on sea surface roughness in order to provide very high resolution wind and current fields

simulations of the 2004 lava flow at etna volcano using the magflow cellular automata model since the mechanical properties of lava change over time lava flows represent a challenge for physically based modeling this change is ruled by a temperature field which needs to be modeled magflow cellular automata ca model was developed for physically based simulations of lava flows in near real time we introduced an algorithm based on the monte carlo approach to solve the anisotropic problem as transition rule of ca a steady state solution of navier stokes equations was adopted in the case of isothermal laminar pressure driven bingham fluid for the cooling mechanism we consider only the radiative heat loss from the surface of the flow and the change of the temperature due to mixture of lavas between cells with different temperatures the model was applied to reproduce a real lava flow that occurred during the 2004 2005 etna eruption the simulations were computed using three different empirical relationships between viscosity and temperature

the chemical composition of martian soil and rocks returned by the mobile alpha proton x ray spectrometer preliminary results from the x ray mode the alpha proton x ray spectrometer apxs on board the rover of the mars pathfinder mission measured the chemical composition of six soils and five rocks at the ares vallis landing site the soil analyses show similarity to those determined by the viking missions the analyzed rocks were partially covered by dust but otherwise compositionally similar to each other they are unexpectedly high in silica and potassium but low in magnesium compared to martian soils and martian meteorites the analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of earth s crust addition of a mafic component and reaction products of volcanic gases to the local rock material is necessary to explain the soil composition

volcanism on mars more than 15 years of planetary exploration of mars have given insight into the geologic processes that have shaped its surface the newly acquired viking data have shown that volcanism is one of the most important geologic processes operating on mars throughout its history in situ chemical analyses of martian soil by the viking lander spacecraft indicate mafic to ultramafic source rocks this is consistent both with available remote sensing data which indicate the presence of mafic minerals such as pyroxene and olivine and with petrologic modeling based on available geophysical data which suggest that martian lavas are probably iron rich and ultramafic these data strongly suggest that basaltic volcanism is widespread on mars and much of the photogeological data may be studied in this context photogeological analysis of the martian surface has shown two main types of volcanic morphologies the first type is central volcanoes which are volcanic landforms developed by continued and prolonged eruption from a point source vent this category includes 1 shields the classic low profile volcanic mountains of which olympus mons is the most spectacular example 2 domes steep sided constructs such as tharsis tholus that may represent lower rates of eruption than the shields or possibly more silicic lava compositions 3 highland patera radially textured low profile volcanoes that occur in the cratered terrain and are interpreted as ash shields 4 alba patera an apparently unique volcanic landform consisting of a vast volcanic center over 1500 km across with flank slopes of less than a tenth of a degree and 5 various small features such as cinder cones the second major category is volcanic plains which are units recognized by several criteria of which the presence of mare ridges and flow lobes are the most useful volcanic plains are subdivided into four main groups 1 simple flows broad smooth to rolling plains that contain numerous mare type ridges but no flow lobes interpreted as being composed of thick single cooling units 2 complex flows displaying multiple overlapping flow lobes interpreted to be indicative of thin multiple cooling units 3 undifierentiated flows plains that typically lack any morphologic identifying feature but are considered to be volcanic partly on the basis of their association with large volcanic centers and 4 questionable plains volcanic units heavily modified by other processes erosion tectonism etc so that their origins are uncertain when these categories of volcanic morphologies are combined with relative age data provided by crater statistics a volcanic history for mars can be derived as follows early heavy bombardment of mars was accompanied and followed by small scale fluvial channeling extensive flood volcanism the plateau plains and ash shield volcanism in the cratered terrain shortly after this time less extensive flood volcanism continued to resurface the planet during formation of the northern southern hemisphere dichotomy central volcanism became more prominent with the development of the alba patera center as well as the older shields and domes of the northern hemisphere early tharsis and elysium regions the development of the tharsis and elysium uplifts may have triggered the release of large scale catastrophic floods producing large channels continued uplift and lithospheric thinning concentrated volcanic activity in the tharsis region producing large shield volcanoes and extensive lava plains both central vent and plains volcanism have been active throughout martian history but the volumes of extrusion have gradually decreased with time this is consistent with a moonlike thermal history involving a lithosphere of increasing thickness with time gradually turning off the volcanism although many questions remain regarding martian volcanism the viking data have provided a remarkable detailed overview of the probable nature of the volcanic history of mars

temperature of an active lava channel from spectral measurements kilauea volcano hawaii a narrow band spectroradiometer was used to determine the characteristic temperatures of a very active channeled lava flow for the phase 50 eruption of pu u o o on the east rift zone of kilauea volcano hawaii during the twilight of 19 february 1992 14 spectra of this activity were acquired over a 51 minute interval 18 29 to 19 20 hawaiian standard time hst from which the thermal distribution of energy of two 18 m2 areas one near the center and one near the margin of the flow may be investigated a twocomponent thermal mixing model applied to the data taken of the center of the channel gave in the most powerful instance 1 8x105 w m2 a crust temperature of 940 c a hot component temperature of 1120 c and a hot radiating area of 60 of the total area a simultaneous spectrum acquired near the channeled flow margin yielded a crust temperature of 586 c and a hot area of only 1 2 of the total area radiating at 1130 c average radiant flux densities recorded for the center of the lava channel 1 3x105 w m2 average are much greater than previous measurements of lava lakes 4 9x103 w m2 or recently emplaced lava flows maximum of 7 2x104 w m2 the energetic nature of this eruption is shown by satellite measurements made at 02 33 hst on 22 february 1992 by the advanced very high resolution radiometer in band 2 0 72 1 10 m these show the utility of using existing satellites with moderate resolution 1 km x 1 km pixels and high temporal coverage eight overpasses each day for hawaii as potential thermal alarms for rapidly assessing the hazard potential of large volcanic eruptions

high resolution thermal inertia derived from the thermal emission imaging system themis thermal model and applications 1 thermal inertia values at 100 m per pixel are determined using nighttime temperature data from the thermal emission imaging system themis on the mars odyssey spacecraft producing the highest resolution thermal inertia data set to date themis thermal inertia values have an overall accuracy of 20 a precision of 10 15 and are consistent with both thermal emission spectrometer orbital and miniature thermal emission spectrometer surface thermal inertia values this data set enables the improved quantification of fine scale surface details observed in high resolution visible images in the tharsis region surface textures and crater rims observed in visible images have no corresponding variation in the themis thermal inertia images indicating that the dust mantle is pervasive at themis scales and is a minimum of a few centimeters and up to 1 2 m thick the thermal inertia of bed form material indicates particle diameters expected for aeolian sediments and these materials are likely currently saltating variations in the thermal inertia within interior layered deposits in hebes chasma can be distinguished and the thermal inertia is too low to be consistent with bedrock or a lava flow thus a secondary emplacement of volcanic material or a volcanic ash deposit is a more likely method of formation higher resolution themis thermal inertia enables the identification of exposed bedrock on the martian surface in nili patera and ares vallis bedrock material corresponds to distinct compositional and morphologic surfaces indicating that a specific unit is exposed and is likely currently being kept free of unconsolidated material by aeolian processes

simulating the thermorheological evolution of channel contained lava flowgo and its implementation in excel flowgo is a one dimensional model that tracks the thermorheological evolution of lava flowing down a channel the model does not spread the lava but instead follows a control volume as it descends a line of steepest descent centred on the channel axis the model basis is the jeffreys equation for newtonian flow modified for a bingham fluid and a series of heat loss equations adjustable relationships are used to calculate cooling crystallization and down channel increases in viscosity and yield strength as well as the resultant decrease in velocity here we provide a guide that allows flowgo to be set up in excel in doing so we show how the model can be executed using a slope profile derived from google tm earth model simplicity and ease of source term input from google tm earth means that this exercise allows i easy access to the model ii quick global application and iii use in a teaching role output is tested using measurements made for the 2010 eruption of piton de la fournaise la reunion island the model is also set up for rapid syneruptive hazard assessment at piton de la fournaise as we show using the example of the response to the june 2014 eruption

ocean convergence and the dispersion of flotsam floating oil plastics and marine organisms are continually redistributed by ocean surface currents prediction of their resulting distribution on the surface is a fundamental long standing and practically important problem the dominant paradigm is dispersion within the dynamical context of a nondivergent flow objects initially close together will on average spread apart but the area of surface patches of material does not change although this paradigm is likely valid at mesoscales larger than 100 km in horizontal scale recent theoretical studies of submesoscales less than 10 km predict strong surface convergences and downwelling associated with horizontal density fronts and cyclonic vortices here we show that such structures can dramatically concentrate floating material more than half of an array of 200 surface drifters covering 20 20 km2 converged into a 60 60 m region within a week a factor of more than 105 decrease in area before slowly dispersing as predicted the convergence occurred at density fronts and with cyclonic vorticity a zipperlike structure may play an important role cyclonic vorticity and vertical velocity reached 0 001 s 1 and 0 01 ms 1 respectively which is much larger than usually inferred this suggests a paradigm in which nearby objects form submesoscale clusters and these clusters then spread apart together these effects set both the overall extent and the finescale texture of a patch of floating material material concentrated at submesoscale convergences can create unique communities of organisms amplify impacts of toxic material and create opportunities to more efficiently recover such material

the southern ocean waves experiment part iii sea surface slope statistics and near nadir remote sensing abstract during the southern ocean waves experiment sowex registered ocean wave topography and backscattered power data at ka band 36 ghz were collected with the nasa scanning radar altimeter sra off the coast of tasmania under a wide range of wind and sea conditions from quiescent to gale force winds with 9 m significant wave height collection altitude varied from 35 m to over 1 km allowing determination of the sea surface mean square slope mss the directional wave spectrum and the detailed variation of backscattered power with incidence angle which deviated from a simple gaussian scattering model the non gaussian characteristics of the backscatter increased systematically with the mss suggesting that a global model to characterize ka band radar backscatter from the sea surface within 25 of nadir might be possible

integrate instead of ignoring base rate neglect as a common fallacy of petroleum explorers when petroleum explorers estimate geological probability of success pos and success case volumes for their prospects they commonly suffer from various biases and fallacies that result in poor assessments using a data set of 25 exploration wells drilled by lundin petroleum on the norwegian continental shelf ncs during the 5 yr period from 2011 to 2015 i demonstrate the base rate neglect fallacy in petroleum exploration lundin explorers consistently and significantly underestimated the geological pos and overestimated the success case volumes relative to the available base rate information on historical exploration success rates and sizes of previously discovered fields in the ncs area these findings are consistent with previous studies of exploration track records of the industry and individual companies explorers erroneously tend to ignore the base rates likely because they do not see them as relevant to the evaluation of their specific prospects as a result exploration portfolios generally fail to deliver on promise however base rate neglect fallacy can be mitigated and eliminated explorers should make an effort to learn the base rates relevant to their prospects and integrate them with prospect evaluations and managers should ensure that modeled portfolio outcomes are consistent with relevant base rates

thermal inertia mapping of mars from 60 s to 60 n twenty micrometer brightness temperatures are used to derive the thermal inertia for 81 of the martian surface between latitudes 60 these data were acquired by the two viking infrared thermal mappers in 1977 and 1978 following the two global dust storms of 1977 the spatial resolution used is 2 in latitude by 2 in longitude and the total range in derived inertia is 1 to 15 10 3 cal cm 2 sec 12 k 1 the distribution of thermal inertia is strongly bimodal with all values of thermal inertia less than 4 10 3 cal cm 2 sec 12 k 1 being associated with three disjoint bright regions mostly in the northern hemisphere sufficient dust is raised in global storms to provide fine material adequate to produce these low inertia areas but the specific deposition mechanism has not been defined at the low resolution used no complete exposures of clean rock were found there is some tendency for darker material to be associated with higher thermal inertia although the trend is far from one to one the distribution of high and low inertia areas is sufficiently nonrandom to produce a variation in whole disk brightness temperature with central meridian longitude this variation and the change in surface kinetic temperature associated with dust storms are factors in establishing the whole disk brightness temperature at radio and infrared wavelengths and will be important for those who use mars as a calibration source

on the use of doppler shift for sea surface wind retrieval from sar the synthetic aperture radar sar doppler centroid has been used to estimate the scatter line of sight radar velocity in weak to moderate ocean surface current environment the sar doppler centroid is dominated by the directionality and strength of wave induced ocean surface displacements in this paper we show how this sea state signature can be used to improve surface wind retrieval from sar doppler shifts of c band radar return signals from the ocean are thoroughly investigated by colocating wind measurements from the ascat scatterometer with doppler centroid anomalies retrieved from envisat asar an empirical geophysical model function cdop is derived predicting doppler shifts at both vv and hh polarization as function of wind speed radar incidence angle and wind direction with respect to radar look direction this function is used into a bayesian inversion scheme in combination with wind from a priori forecast model and the normalized radar cross section nrcs the benefit of doppler for sar wind retrieval is shown in complex meteorological situations such as atmospheric fronts or low pressure systems using in situ information validation reveals that this method helps to improve the wind direction retrieval uncertainty of the calibration of doppler shift from envisat asar hampers the inversion scheme in cases where nrcs and model wind are accurate and in close agreement the method is however very promising with respect of future sar missions in particular sentinel 1 where the doppler centroid anomaly will be more robustly retrieved

alkaline volcanic rocks from the columbia hills gusev crater mars 1 irvine backstay and wishstone are the type specimens for three classes of fine grained or fragmental relatively unaltered rocks with distinctive thermal emission spectra found as float on the flanks of the columbia hills chemical analyses indicate that these rocks are mildly alkaline basalt trachybasalt and tephrite respectively their mineralogy consists of na and k rich feldspar s low and high ca pyroxenes ferroan olivine fe ti and possibly cr oxides phosphate and possibly glass the texture of wishstone is consistent with a pyroclastic origin whereas irvine and backstay are lavas or possibly dike rocks chemical compositions of these rocks plot on or near liquid lines of descent for most elements calculated for adirondack class rocks olivine rich basalts from the gusev plains at various pressures from 0 1 to 1 0 gpa we infer that wishstone backstay and irvine class magmas may have formed by fractionation of primitive oxidized basaltic magma similar to adirondack class rocks the compositions of all these rocks reveal that the gusev magmatic province is alkaline distinct from the subalkaline volcanic rocks thought to dominate most of the planet s surface the fact that differentiated volcanic rocks were not encountered on the plains prior to ascending husband hill may suggest a local magma source for volcanism beneath gusev crater

relative dating of hawaiian lava flows using multispectral thermal infrared images a new tool for geologic mapping of young volcanic terranes the weathering of hawaiian basalts in arid and semiarid environments is accompanied by change in their thermal infrared emittance spectra the spectral differences can be measured and mapped with multispectral imaging systems the differences appear to be related to the degree of development preservation and alteration of glassy crusts the oxidation of iron and the accretion of silica rich surface veneers because the measurements are quantitative and in image format they are useful for estimating relative ages in geologic mapping of lava flows in hawaii this technique is most diagnostic for distinguishing among sparsely vegetated flows less than 1 5 ka in age

regional dust deposits on mars physical properties age and history major dust storms on mars play an important role in the deposition and removal of fine dust material thermal radar and visual remote sensing observations provide important constraints on the martian regolith which have been used to determine the location and physical properties of regional dust deposits these deposits are located in three northern equatorial regions tharsis 20 s to 50 n 60 to 190 w arabia 5 s to 30 n 300 to 360 w and elysium 10 to 30 n 210 to 225 w they are covered by fine 2 40 m bright albedo 0 27 particles with fewer exposed rocks and coarse deposits than found elsewhere dust is currently deposited uniformly throughout the equatorial region at a rate of 40 m global storm over geologic time the rate of accumulation may vary from 0 to 250 m yr due to changes in atmospheric conditions produced by orbital variations dust deposited during global storms is subsequently removed only from dark regions resulting in a net accumulation in the low inertia bright regions the thickness of these current dust deposits is 0 1 2 m the thermal inertia places a lower limit of 0 1 m on the thickness of these deposits while the sparse but ubiquitous presence of exposed rocks and the degree of visible mantling indicate that the thickness is less than 5 m dual polarization radar observations of a very rough texture in tharsis are consistent with this model with a 2 m thick dust layer burying most of the surface rocks but permitting radar sampling of the rough subsurface based on their thickness and rate of accumulation the age of these deposits is 105 106 years suggesting a cyclic process of deposition and removal one possible cause may be cyclic variations in the magnitude and location of maximum wind velocities related to variations in mars orbit at present perihelion and maximum wind velocities occur in the south whereas regional dust deposits occur in the north suggesting net transport from south to north orbital parameters oscillate with periods ranging from 5 104 to 106 years the agreement between these periods and the dust deposit age suggests a possible link at different stages in orbit evolution maximum wind velocities will occur in the north with subsequent erosion and redistribution of the accumulated fines based on this model much of the uppermost martian surface is very young and is being continually reworked

normalized measures of exploration performance in terms of basin sediment volumes the normalized measures of exploration performance defined in this paper are the exploratory drilling density in feet per cubic mile of sediments and the hydrocarbon discovery density in boe per cubic mile these density measures provide a convenient means for summarizing the status of exploration in the sedimentary provinces of the lower 48 states of the united states revealing that the smaller hydrocarbon rich provinces have been explored much more intensely than the larger ones the most important application of the drilling and hydrocarbon discovery densities is in defining normalized discovery functions that is the relationships between the normalized measures of cumulative exploratory drilling and discoveries normalized rather than absolute discovery functions are necessary for proper comparison of the results of exploration in regions or depth zones of differing sizes the normalized drilling and discovery measures are also useful for developing meaningful statistics of exploration performance

intense deformation field at oceanic front inferred from directional sea surface roughness observations fine scale current gradients at the ocean surface can be observed by sea surface roughness more specifically directional surface roughness anomalies are related to the different horizontal current gradient components this paper reports results from a dedicated experiment during the laser lagrangian submesoscale experiment drifter deployment a very sharp front 50 m wide is detected simultaneously in drifter trajectories sea surface temperature and sea surface roughness a new observational method is applied using sun glitter reflections during multiple airplane passes to reconstruct the multi angle roughness anomaly this multi angle anomaly is consistent with wave current interactions over a front including both cross front convergence and along front shear with cyclonic vorticity qualitatively results agree with drifters and x band radar observations quantitatively the sharpness of roughness anomaly suggests intense current gradients 0 3 m s 1 over the 50 m wide front this work opens new perspectives for monitoring intense oceanic fronts using drones or satellite constellations

spatial variations in lava flow field thermal structure and effusion rate derived from very high spatial resolution hyperspectral mivis data 1 high spatial resolution hyperspectral measurements of volcanic thermal anomalies allow for an unconstrained solution of a two component thermal model this can be used for identification of lava flow emplacement style and the calculation of lava flow heat and volume flux the multispectral infrared and visible imaging spectrometer mivis is an airborne sensor equipped with 72 bands in the short infrared range and 10 bands in the thermal infrared region of the spectrum we used mivis acquired for mount etna italy during the july august 2001 eruption to solve the dual band equations in an unconstrained fashion using three bands of unsaturated data our results suggest a complex thermal structure for etnean lava flows this is characterized by a downflow transition from a lightly crusted active channel to a more heavily crusted distal section both surrounded by zones of stagnant cooling flow where exposed molten material is absent and maximum temperatures are thus lower the total flow field effusion rate obtained for 29 july 2001 0700 local time of 8 16 m3 s is in excellent agreement with that obtained from ground based measurements and advanced very high resolution radiometer data flow by flow effusion rates obtained from the mivis data vary depending on whether the vent is linked to the central conduit or the dyke that was injected from greater depth as well as vent elevation with lower elevation vents experiencing higher effusion rates

improved statistical method for assessment of undiscovered petroleum resources a statistically significant straight line correlation exists between logarithms of oil or gas field sizes and order of discovery in some of australia s petroleum provinces the correlation is predicted by the hypotheses 1 that the probability of discovery of each field is proportional to size raised to a constant power lambda lgr and 2 that fields are discovered without replacement from a population with a lognormal size distribution a computer program has been developed that uses extrapolations of the straight line to predict the number and size of future discoveries the program takes into account a dependent relationship among lambda and the average slope and intercept of the fitted lines and the average standard deviation of the residuals that is indicated by the hypotheses the new field wildcat drilling required is estimated using predicted success rates

ducks low cost thermal monitoring units for near vent deployment abstract during 1999 we designed and tested a thermal monitoring system to provide a cheap robust modular real time system capable of surviving the hostile conditions encountered proximal to active volcanic vents in november 2000 the first system was deployed at pu u o o kilauea hawai i to target persistently active vents aside from some minor problems such as sensor damage due to tampering this system remained operational until january 2004 the success of the prototype system led us to use the blueprint for a second installation at stromboli aeolian islands italy this was deployed dug into a bomb proof bunker during may 2002 and survived the april 2003 paroxysmal eruption despite being located just 250 m from the vent in both cases careful waterproofing of connectors and selection of suitable protection has prevented water damage and corrosion in the harsh atmosphere encountered at the crater rim the pu u o o system cost us 10 000 and comprises four modules sensors transmission and power hub repeater station and reception site the sensor component consists of three thermal infrared thermometers housed in pelican cases fitted with germanium arsenide selenium windows two 1 field of view fov sensors allow specific vents to be targeted and a 60 fov sensor provides a crater floor overview a hard wire connection links to a pelican case housed microprocessor modem and power module from here data are transmitted via a repeater site to a dedicated pc at the hawaiian volcano observatory here data are displayed with a delay of 3 s between acquisition and display the modular design allows for great flexibility at stromboli 1 and 15 fov sensor modules can be switched depending changes in activity style and crater geometry in addition a direct line of site to the stromboli reception center negates the repeater site requirement reducing the cost to us 5500 for a single sensor system we have also constructed self contained units with internal data loggers for us 1500 unit these have been tested at kilauea stromboli etna masaya santiaguito fuego pacaya poas soufriere hills villarrica and erta ale these instruments have proved capable of detecting thermal signals associated with 1 gas emission 2 gas jetting events 3 crater floor collapse 4 lava effusion 5 lava flow in tubes 6 lava lake activity 7 lava dome activity and 8 crater lake skin temperature

forecasting lava flow paths by a stochastic approach 1 a stochastic model named downflow is presented to forecast possible lava flow paths with the aim of hazard assessment and mitigation the model relies on the fact that lava flow emplacement is in many cases controlled by topography the potential inundation area of the flow is determined by considering a number of steepest paths over stochastic perturbations of the original topography since the code requires very short computational time and few input data the model proved to be a very useful tool to obtain real time predictions during the initial phase of an eruption the necessary topographic information can be obtained by photogrammetry radar altimetry or laser scanning techniques downflow has been successfully applied to a number of flows including the september 2004 lava flow where updated topographies were available

using infrared satellite data to drive a thermo rheological stochastic lava flow emplacement model a method for near real time volcanic hazard assessment 1 we combine two flow simulation models to provide a computationally efficient means of predicting the final dimensions of active lava flows by using a stochastic approach to predict all the downhill paths that a lava flow could possibly follow and a thermo rheological model to terminate these paths once the predicted cooling limited length for the flow has been attained this approach allows for rapid assessment of the area likely to be inundated by lava the 1991 1993 eruption of mount etna is used as a case study lava effusion rate exerts a strong control on the maximum length a lava flow can attain and we demonstrate how the model can be driven by time varying effusion rates obtained from infrared satellite data as such data are obtained in near real time this approach allows flow simulations to be updated in a timely manner in response to changing eruption conditions

mapping the agulhas current from space an assessment of asar surface current velocities 1 over 2 years of surface current information collected in the agulhas current region and derived from the doppler centroid anomalies of envisat s advanced synthetic aperture radar asar are examined the sources of errors and potential use of asar surface current velocities for oceanographic research are assessed asar surface current velocities are compared to surface drifter data and merged altimetry observations maps of sea surface temperature are used to establish the asar s capacity to capture the synoptic circulation discrepancies between observed and predicted asar velocities result predominantly from inadequate wind corrections combined with radar incidence angles below 30 occasionally observed wind induced outliers cause a bias in the estimated asar velocities but do not affect the ability of the asar to systematically image regions of strong surface current flow and shear time averaged maps of asar derived surface current velocity seem able to accurately capture the position as well as the intensity of the agulhas current the ability of the asar to pick up the smaller features of the circulation along the shelf break also shows that variability along the agulhas bank is of the same order of magnitude as that observed in the agulhas retroflection asar surface current velocities offer a very good complement to altimetry in regions where the mean dynamic topography is poorly resolved the quasi synoptic nature of asar acquisitions combined with the relatively high resolution of asar surface current velocities also make it attractive for studies of submesoscale processes and western boundary current dynamics

near real time forecasting of lava flow hazards during the 12 13 january 2011 etna eruption we are grateful to eumetsat for seviri data to nasa for modis data and tonoaafor avhrr data the authors thank one anonymous reviewer and v acocella for their helpful and constructive comments this study was performed with the financial support from the v3 lava project ingv dpc 2007 2009 contract

morphometric properties of martian volcanoes 1 mars orbiter laser altimeter mola data have been used to construct digital elevation models dem of the martian volcanoes in order to determine height flank slope caldera depth and volumes summit elevations range from 21 1 km to 0 5 km and relief varies from 1 0 km to almost 22 km average flank slopes are in the range of 1 to 10 consistent with basaltic shield volcanism the very low slopes of highland patera are also consistent with pyroclastic volcanism minimum volumes range from 1012 to 1015 m3 estimates of the time required to build these volcanoes on the basis of long term terrestrial eruption rates range from hundreds of thousands to tens of millions of years

effects of martian conditions on numerically modeled cooling limited channelized lava flows 1 we used the flowgo thermorheological model to examine the effects of martian gravitational and environmental conditions on the cooling limited behavior of lava flowing in a channel the largest effect is due to the lower gravity on mars as compared to earth which causes lava to flow more slowly the lower velocity means that heat loss per distance down a mars channel is greater even though the lower velocity also produces a higher percentage cover of insulating crust gravity alone causes the mars flow to be 65 km shorter than an earth flow with an equivalent volumetric flow rate the cooler ambient mars atmosphere causes a slight increase in heat loss by forced convection this slows the flow a bit more resulting in a very slight increase in heat loss per distance by all mechanisms and decreases the modeled flow length by 1 km a difference well below our model uncertainty replacing terrestrial values of atmospheric density viscosity thermal conductivity heat capacity and cubic expansivity makes convection less efficient and increases flow length by 15 km nevertheless at the same volumetric flow rate lava flows 50 km less far under martian conditions than under terrestrial conditions our specific model flow has a volumetric flow rate of 5000 m3 s 1 and traveled 190 km down a channel on a constant 7 slope this volumetric flow rate is slightly less than the maximum rates during the 1783 1785 laki eruption and is 5 10 times greater than those of typical mauna loa eruptions

sea surface kinematics from near nadir radar measurements doppler radars at all incidence angles measure mean velocities and spreads that have complex relations to oceanic motions with opportunities to measure winds waves and currents here we extend previous theoretical models of backscatter and doppler using a kirchhoff approximation and the physical optics model we show that in ka band around 12 incidence range resolved measurements of doppler and backscatter provide unambiguous estimations of the wave spectrum and surface current this property is illustrated with numerical examples and airborne data from the air surface water ocean topography instrument the same measurement conditions can be exploited for global ocean mapping from the low earth orbit sensor satellite configuration

apparent thermal inertia and the surface heterogeneity of mars abstract thermal inertia derivation techniques generally assume that surface properties are uniform at horizontal scales below the footprint of the observing instrument and to depths of several decimeters consequently surfaces with horizontal or vertical heterogeneity may yield apparent thermal inertia which varies with time of day and season to investigate these temporal variations we processed three mars years of mars global surveyor thermal emission spectrometer observations and produced global nightside and dayside seasonal maps of apparent thermal inertia these maps show broad regions with diurnal and seasonal differences up to 200 j m 2 k 1 s 1 2 at mid latitudes 60 s to 60 n and 600 j m 2 k 1 s 1 2 or greater in the polar regions we compared the seasonal mapping results with modeled apparent thermal inertia and created new maps of surface heterogeneity at 5 resolution delineating regions that have thermal characteristics consistent with horizontal mixtures or layers of two materials the thermal behavior of most regions on mars appears to be dominated by layering with upper layers of higher thermal inertia e g duricrusts or desert pavements over fines prevailing in mid latitudes and upper layers of lower thermal inertia e g dust covered rock soils with an ice table at shallow depths prevailing in polar regions less common are regions dominated by horizontal mixtures such as those containing differing proportions of rocks sand dust and duricrust or surfaces with divergent local slopes other regions show thermal behavior that is more complex and not well represented by two component surface models these results have important implications for mars surface geology climate modeling landing site selection and other endeavors that employ thermal inertia as a tool for characterizing surface properties

explosive lava water interactions ii self organization processes among volcanic rootless eruption sites in the 1783 1784 laki lava flow iceland we have applied quantitative geospatial analyses to rootless eruption sites in the hnuta and hrossatungur groups of the 1783 1784 laki lava flow to establish how patterns of spatial distribution can be used to obtain information about rootless cone emplacement processes and paleo environments this study utilizes sample size dependent nearest neighbor nn statistics and voronoi tessellations to quantify the spatial distribution of rootless eruption sites and validate the use of statistical nn analysis as a remote sensing tool our results show that rootless eruption sites cluster in environments with abundant lava and water resources but competition for limited groundwater in these clusters can cause rootless eruption sites to develop repelled distributions this pattern of self organization can be interpreted within the context of resource availability and depletion topography tends to concentrate lava fuel and water coolant within topographic lows thereby promoting explosive lava water interactions in these regions given an excess supply of lava within broad sheet lobes rootless eruption sites withdraw groundwater from their surroundings until there is insufficient water to maintain analogs to explosive molten fuel coolant interactions rootless eruption sites may be modeled as a network of water extraction wells that draw down the water table in their vicinity rootless eruptions at locations with insufficient groundwater may either fail to initiate or terminate before explosive activity has ceased at nearby locations with a greater supply of water thus imparting a repelled distribution to observed rootless eruption sites

mosaicking of global planetary image datasets 1 techniques and data processing for thermal emission imaging system themis multi spectral data 1 the mosaicking of global planetary data sets allows for the examination of local regional and global scale processes on all planetary bodies processing techniques that allow us and other users to crate mosaics of tens of thousands of images are documented along with the associated errors introduced by each image processing algorithm these techniques e g non uniformity correction running contrast stretches line and row correlated noise removal and random noise removal were originally developed for the 2001 mars odyssey thermal emission imaging system themis infrared multispectral imager data but can be adapted and applied to other data sets by the alteration of input parameters the techniques for mosaicking planetary image data sets e g image registration blending and normalization are also presented along with the generation of qualitative and quantitative products these techniques are then applied to generate themis daytime and nighttime infrared viking context imager ctx and mars orbiter camera moc visible mosaics using a variety of input and output types at a variety of scales by creating mosaics of the same area using different data sets such as those that illustrate compositional diversity thermophysical properties or small scale morphology it is possible to view the surface of the planet and geologic problems through many different perspectives in addition to the techniques used to create large scale seamless mosaics we also present the themis daytime and nighttime relative temperature global mosaics which are the highest resolution 100m pixel global scale data sets available for mars to date

wind wave induced velocity in ati sar ocean surface currents first experimental evidence from an airborne campaign conventional and along track interferometric ati synthetic aperture radar sar sense the motion of the ocean surface by measuring the doppler shift of reflected signals measurements are affected by a wind wave induced artefact surface velocity wasv which was modelled theoretically in past studies and has been estimated empirically only once before with envisat asar by mouche et al 2012 an airborne campaign in the tidally dominated irish sea served to evaluate this effect and the current retrieval capabilities of a dual beam sar interferometer known as wavemill a comprehensive collection of wavemill airborne data acquired in a star pattern over a well instrumented validation site made it possible for the first time to estimate the magnitude of the wasv and its dependence on azimuth and incidence angle from data alone in light wind 5 5 m s and moderate current 0 7 m s conditions the wind wave induced contribution to the measured ocean surface motion reaches up to 1 6 m s upwind with a well defined 2nd order harmonic dependence on direction to the wind the magnitude of the wasv is found to be larger at lower incidence angles the airborne wasv results show excellent consistency with the empirical wasv estimated from envisat asar these results confirm that sar and ati surface velocity estimates are strongly affected by wasv and that the wasv can be well characterized with knowledge of the wind knowledge and of the geometry these airborne results provide the first independent validation of mouche et al 2012 and confirm that the empirical model they propose provides the means to correct airborne and spaceborne sar and ati sar data for wasv to obtain accurate ocean surface current measurements after removing the wasv the airborne wavemill retrieved currents show very good agreement against adcp measurements with a root mean square error rmse typically around 0 1 m s in velocity and 10 in direction this article is protected by copyright all rights reserved

direct ocean surface velocity measurements from space improved quantitative interpretation of envisat asar observations previous analysis of advanced synthetic aperture radar asar signals collected by esa s envisat has demonstrated a very valuable source of high resolution information namely the line of sight velocity of the moving ocean surface this velocity is estimated from a doppler frequency shift consistently extracted within the asar scenes the doppler shift results from the combined action of near surface wind on shorter waves longer wave motion wave breaking and surface current both kinematic and dynamic properties of the moving ocean surface roughness can therefore be derived from the asar observations the observations are compared to simulations using a radar imaging model extended to include a doppler shift module the results are promising comparisons to coincident altimetry data suggest that regular account of this combined information would advance the use of sar in quantitative studies of ocean currents

rootless cones on mars a consequence of lava ground ice interaction fields of small cratered cones on mars are interpreted to have formed by rootless eruptions due to explosive interaction of lava with ground ice contained within the regolith beneath the flow melting and vaporization of the ice and subsequent explosive expansion of the vapour act to excavate the lava and construct a rootless cone around the explosion site similar features are found in iceland where flowing lava encountered water saturated substrates the martian cones have basal diameters of c 30 1000 m and are located predominantly in the northern volcanic plains high resolution mars orbiter camera images offer significant improvements over viking data for interpretation of cone origins a new model of the dynamics of cone formation indicates that very modest amounts of water ice are required to initiate and sustain the explosive interactions that produced the observed features this is consistent with the likely low availability of water ice in the martian regolith the scarcity of impact craters on many of the host lava flows indicates very young ages suggesting that ground ice was present as recently as less than 10 l00 ma and may persist today rootless cones therefore act as a spatial and temporal probe of the distribution of ground ice on mars which is of key significance in understanding the evolution of the martian climate the location of water in liquid or solid form is of great importance to future robotic and human exploration strategies and to the search for extraterrestrial life

a chronology of the 1991 to 1993 mount etna eruption using advanced very high resolution radiometer data implications for real time thermal volcano monitoring between december 1991 and march 1993 a continuous effusive eruption at mount etna built a 7 6 km2 lava flow field flows extended to within 1 km of the town of zafferana before a successful artificial diversion was carried out higher up the volcano during this eruption the spaceborne advanced very high resolution radiometer avhrr acquired 308 images on which the activity could be detected since these data can be freely and directly available such coverage potentially allows regular real time monitoring ground observations and a flow map that we produced using a spot image and electronic distance measurement allowed us to develop and test data extraction techniques avhrr radiance maps were consistent with known locations of surface activity these documented the transition from channel to tube fed phases the changing threat to zafferana and flow diversion quantitative analysis of the avhrr data enabled estimation of active lava area thermal flux effusion rates and total flow field volume our estimates for eruption rate and total flow field volume 5 6 to 7 6 m3 s and 220 106 to 300 106 m3 respectively are in agreement with published ground based estimates of 5 8 m3 s and 235 106 m3 these correlations demonstrate the high degree of confidence that can now be placed in interpretations of avhrr time series for eruptions where ground based data are scanty