Stochastic inversion of time-lapse geophysical data to characterize the vadose zone at the Arrenaes field site (Denmark)

NASA Astrophysics Data System (ADS)

Marie, S.; Irving, J. D.; Looms, M. C.; Nielsen, L.; Holliger, K.

2011-12-01

Geophysical methods such as ground-penetrating radar (GPR) can provide valuable information on the hydrological properties of the vadose zone. In particular, there is evidence to suggest that the stochastic inversion of such data may allow for significant reductions in uncertainty regarding subsurface van-Genuchten-Mualem (VGM) parameters, which characterize unsaturated hydrodynamic behaviour as defined by the combination of the water retention and hydraulic conductivity functions. A significant challenge associated with the use of geophysical methods in a hydrological context is that they generally exhibit an indirect and/or weak sensitivity to the hydraulic parameters of interest. A novel and increasingly popular means of addressing this issue involves the acquisition of geophysical data in a time-lapse fashion while changes occur in the hydrological condition of the probed subsurface region. Another significant challenge when attempting to use geophysical data for the estimation of subsurface hydrological properties is the inherent non-linearity and non-uniqueness of the corresponding inverse problems. Stochastic inversion approaches have the advantage of providing a comprehensive exploration of the model space, which makes them ideally suited for addressing such issues. In this work, we present the stochastic inversion of time-lapse zero-offset-profile (ZOP) crosshole GPR traveltime data, collected during a forced infiltration experiment at the Arreneas field site in Denmark, in order to estimate subsurface VGM parameters and their corresponding uncertainties. We do this using a Bayesian Markov-chain-Monte-Carlo (MCMC) inversion approach. We find that the Bayesian-MCMC methodology indeed allows for a substantial refinement in the inferred posterior parameter distributions of the VGM parameters as compared to the corresponding priors. To further understand the potential impact on capturing the underlying hydrological behaviour, we also explore how the posterior VGM parameter distributions affect the hydrodynamic characteristics. In doing so, we find clear evidence that the approach pursued in this study allows for effective characterization of the hydrological behaviour of the probed subsurface region.

Japan's exploration of vertical holes and subsurface caverns on the Moon and Mars

NASA Astrophysics Data System (ADS)

Haruyama, J.; Kawano, I.; Kubota, T.; Yoshida, K.; Kawakatsu, Y.; Kato, H.; Otsuki, M.; Watanabe, K.; Nishibori, T.; Yamamoto, Y.; Iwata, T.; Ishigami, G.; Yamada, T. T.

2013-12-01

Recently, gigantic vertical holes exceeding several tens of meters in diameter and depth were discovered on the Moon and Mars. Based on high-resolution image data, lunar holes and some Martian pits (called 'holes' hereafter) are probably skylights of subsurface caverns such as lava tubes or magma chambers. We are starting preparations for exploring the caverns through the vertical holes. The holes and subsurface caverns have high potential as resources for scientific studies. Various important geological and mineralogical processes could be uniquely and effectively observed inside these holes and subsurface caverns. The exposed fresh lava layers on the vertical walls of the lunar and Martian holes would provide information on volcanic eruption histories. The lava layers may also provide information on past magnetic fields of the celestial bodies. The regolith layers may be sandwiched between lava layers and may preserve volatile elements including solar wind protons that could be a clue to understanding past solar activities. Water molecules from solar winds or cometary/meteorite impacts may be stored inside the caverns because of mild temperatures there. The fresh lava materials forming the walls and floors of caverns might trap endogenic volatiles from magma eruptions that will be key materials for revealing the formation and early evolution of the Moon and Mars. Furthermore, the Martian subsurface caverns are highly expected to be life cradles where the temperatures are probably stable and that are free from ultra-violet and other cosmic rays that break chemical bonds, thus avoiding polymerization of molecules. Discovering extraterrestrial life and its varieties is one of our ultimate scientific purposes for exploring the lunar and Martian subsurface caverns. In addition to scientific interests, lunar and Martian subsurface caverns are excellent candidates for future lunar bases. We expect such caverns to have high potential due to stable temperatures; absence of ultra-violet rays, cosmic rays, and meteorite impacts; spacious volumes based on analogues of terrestrial lava tubes; tight walls and floors possibly glass-coated by rapid cooling inside the caverns; and so on. Exploration of subsurface caverns of the Moon and Mars would provide answers to various basic and applied scientific questions fundamental to understanding the nature of the Moon, Mars, and life. Furthermore, it could provide knowledge to enable constructing lunar and Martian bases for robotic and/or manned activities there. However, Japan does not have the technology for soft-landing on gravitational celestial bodies. First, we should acquire that technology. Next, we should acquire the technology for approaching and descending into holes that could be skylights of caverns. We should also develop the technology to move on the floors where there are many boulders and/or a mound of dusts. We should also consider how to investigate the dark inside of the caverns. There are many engineering challenges for exploring the lunar and Martian subsurface caverns, but our team is prepared to meet them.

Human utilization of subsurface extraterrestrial environments.

PubMed

Boston, P J; Frederick, R D; Welch, S M; Werker, J; Meyer, T R; Sprungman, B; Hildreth-Werker, V; Thompson, S L; Murphy, D L

2003-06-01

Caves have been used in the ancient past as shelter or habitat by many organisms (including humans). Since antiquity, humans have explored caves for the minerals they contain and sometimes for ceremonial purposes. Over the past century, caves have become the target of increasing exploration, scientific research, and recreation. The use of caves on extraterrestrial bodies for human habitation has been suggested by several investigators. Lunar lava tube bases received early attention because lava tubes were clearly visible in lunar images from the Apollo Era. More recently, Mars Observer Camera data has shown us clear evidence of large tubes visible in a number of volcanic regions on Mars. The budding field of cave geomicrobiology has direct application to questions about subsurface life on other planets. Caves contain many unusual organisms making their living from unlikely materials like manganese, iron, and sulfur. This makes caves and other subsurface habitats prime targets for astrobiological missions to Mars and possibly other bodies. We present the results of a completed Phase I and on-going Phase II NASA Institute for Advanced Concepts (NIAC) study that intensively examines the possibilities of using extraterrestrial caves as both a resource for human explorers and as a highly promising scientific target for both robotic and future human missions to Mars and beyond.

Mars Analog Rio Tinto Experiment (MARTE): 2003 Drilling Campaign to Search for a Subsurface Biosphere at Rio Tinto Spain

NASA Technical Reports Server (NTRS)

Stoker, Carol; Dunagan, Stephen; Stevens, Todd; Amils, Ricardo; Gomez-Elvira, Javier; Fernandez, David; Hall, James; Lynch, Kennda; Cannon, Howard; Zavaleta, Jhony

2004-01-01

The MARTE (Mars Astrobiology Research and Technology Experiment) project, an ASTEP field experiment, is exploring for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Tinto River- or Rio Tinto- in southwestern Spain. It is also demonstrating technology needed to search for a subsurface biosphere on Mars. The project has three primary objectives: (1) search for and characterize subsurface life at Rio Tinto along with the physical and chemical properties and sustaining energy sources of its environment, (2) perform a high fidelity simulation of a robotic Mars drilling mission to search for life, and (3) demonstrate the drilling, sample handling, and instrument technologies relevant to searching for life on Mars. The simulation of the robotic drilling mission is guided by the results of the aseptic drilling campaign to search for life at Rio Tinto. This paper describes results of the first phase of the aseptic drilling campaign.

Target-oriented retrieval of subsurface wave fields - Pushing the resolution limits in seismic imaging

NASA Astrophysics Data System (ADS)

Vasconcelos, Ivan; Ozmen, Neslihan; van der Neut, Joost; Cui, Tianci

2017-04-01

Travelling wide-bandwidth seismic waves have long been used as a primary tool in exploration seismology because they can probe the subsurface over large distances, while retaining relatively high spatial resolution. The well-known Born resolution limit often seems to be the lower bound on spatial imaging resolution in real life examples. In practice, data acquisition cost, time constraints and other factors can worsen the resolution achieved by wavefield imaging. Could we obtain images whose resolution beats the Born limits? Would it be practical to achieve it, and what are we missing today to achieve this? In this talk, we will cover aspects of linear and nonlinear seismic imaging to understand elements that play a role in obtaining "super-resolved" seismic images. New redatuming techniques, such as the Marchenko method, enable the retrieval of subsurface fields that include multiple scattering interactions, while requiring relatively little knowledge of model parameters. Together with new concepts in imaging, such as Target-Enclosing Extended Images, these new redatuming methods enable new targeted imaging frameworks. We will make a case as to why target-oriented approaches to reconstructing subsurface-domain wavefields from surface data may help in increasing the resolving power of seismic imaging, and in pushing the limits on parameter estimation. We will illustrate this using a field data example. Finally, we will draw connections between seismic and other imaging modalities, and discuss how this framework could be put to use in other applications

Subsurface site conditions and geology in the San Fernando earthquake area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duke, C.M.; Johnson, J.A.; Kharraz, Y.

1971-12-01

The report presents the progress to date in establishing the facts about dynamic subsurface properties and geological features in the area affected by the San Fernando earthquake of February 9, 1971. Special emphasis is given to the locations of accelerographs, seismoscopes and Seismological Field Survey aftershock instruments. Thirty shallow geophysical surveys were made for determination of S and P velocities, with damping measured at some sites. Deep velocity data were obtained from geophysical surveys by others. Soil Mechanics and water well borings by others were utilized. Published and ongoing geological studies were applied. Results are presented in the form ofmore » five geological cross-sections, nine subsurface exploration models extending through basement complex to depths of 14,000 feet, a general geologic map, the shallow geophysical surveys, and selected data on damping.« less

The Astrobiology of the Subsurface: Exploring Cave Habitats on Earth, Mars and Beyond

NASA Technical Reports Server (NTRS)

Boston, Penelope Jane

2016-01-01

We are using the spectacular underground landscapes of Earth caves as models for the subsurfaces of other planets. Caves have been detected on the Moon and Mars and are strongly suspected for other bodies in the Solar System including some of the ice covered Ocean Worlds that orbit gas giant planets. The caves we explore and study include many extreme conditions of relevance to planetary astrobiology exploration including high and low temperatures, gas atmospheres poisonous to humans but where exotic microbes can flourish, highly acidic or salty fluids, heavy metals, and high background radiation levels. Some cave microorganisms eat their way through bedrock, some live in battery acid conditions, some produce unusual biominerals and rare cave formations, and many produce compounds of potential pharmaceutical and industrial significance. We study these unique lifeforms and the physical and chemical biosignatures that they leave behind. Such traces can be used to provide a "Field Guide to Unknown Organisms" for developing life detection space missions.

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation

PubMed Central

Ren, Shuting; Yan, Bei; Zainal Abidin, Ilham Mukriz; Wang, Yi

2017-01-01

A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size. PMID:28758985

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation.

PubMed

Li, Yong; Ren, Shuting; Yan, Bei; Zainal Abidin, Ilham Mukriz; Wang, Yi

2017-07-31

A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoak, T.E.; Klawitter, A.L.

Fractured production trends in Piceance Basin Cretaceous-age Mesaverde Group gas reservoirs are controlled by subsurface structures. Because many of the subsurface structures are controlled by basement fault trends, a new interpretation of basement structure was performed using an integrated interpretation of Landsat Thematic Mapper (TM), side-looking airborne radar (SLAR), high altitude, false color aerial photography, gas and water production data, high-resolution aeromagnetic data, subsurface geologic information, and surficial fracture maps. This new interpretation demonstrates the importance of basement structures on the nucleation and development of overlying structures and associated natural fractures in the hydrocarbon-bearing section. Grand Valley, Parachute, Rulison, Plateau,more » Shire Gulch, White River Dome, Divide Creek and Wolf Creek fields all produce gas from fractured tight gas sand and coal reservoirs within the Mesaverde Group. Tectonic fracturing involving basement structures is responsible for development of permeability allowing economic production from the reservoirs. In this context, the significance of detecting natural fractures using the intergrated fracture detection technique is critical to developing tight gas resources. Integration of data from widely-available, relatively inexpensive sources such as high-resolution aeromagnetics, remote sensing imagery analysis and regional geologic syntheses provide diagnostic data sets to incorporate into an overall methodology for targeting fractured reservoirs. The ultimate application of this methodology is the development and calibration of a potent exploration tool to predict subsurface fractured reservoirs, and target areas for exploration drilling, and infill and step-out development programs.« less

Seismic model study of Patrick Draw field, Wyoming: a stratigraphic trap in the Upper Cretaceous Almond Formation

USGS Publications Warehouse

Anderson, Robert C.; Ryder, Robert T.

1978-01-01

The Patrick Draw field, located on the eastern flank of the Rock Springs uplift in the Washakie basin of southwestern Wyoming, was discovered in 1959 without the use of geophysical methods. The field is a classic example of a stratigraphic trap, where Upper Cretaceous porous sandstone units pinch out on a structural nose. Two-dimensional seismic modeling was used to construct the seismic waveform expressions of the Patrick Draw field, and to better understand how to explore for other 'Patrick Draw' fields. Interpretation of the model shows that the detection of the reservoir sand is very difficult, owing to a combination of acoustic contrasts and bed thickness. Because the model included other major stratigraphic units in the subsurface, several stratigraphic traps are suggested as potential exploration targets.

An Autonomous Cryobot Synthetic Aperture Radar for Subsurface Exploration of Europa

NASA Astrophysics Data System (ADS)

Pradhan, O.; Gasiewski, A. J.

2015-12-01

We present the design and field testing of a forward-looking end-fire synthetic aperture radar (SAR) for the 'Very deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer' (VALKYRIE) ice-penetrating cryobot. This design demonstrates critical technologies that will support an eventual landing and ice penetrating mission to Jupiter's icy moon, Europa. Results proving the feasibility of an end-fire SAR system for vehicle guidance and obstacle avoidance in a sub-surface ice environment will be presented. Data collected by the SAR will also be used for constructing sub-surface images of the glacier which can be used for: (i) mapping of englacial features such as crevasses, moulins, and embedded liquid water and (ii) ice-depth and glacier bed analysis to construct digital elevation models (DEM) that can help in the selection of crybot trajectories and future drill sites for extracting long-term climate records. The project consists of three parts, (i) design of an array of four conformal cavity-backed log-periodic folded slot dipole array (LPFSA) antennas that form agile radiating elements, (ii) design of a radar system that includes RF signal generation, 4x4 transmit-receive antenna switching and isolation and digital SAR data processing and (iii) field testing of the SAR in melt holes. The antennas have been designed, fabricated, and lab tested at the Center for Environmental Technology (CET) at CU-Boulder. The radar system was also designed and integrated at CET utilizing rugged RF components and FPGA based digital processing. Field testing was performed in conjunction with VALKYRIE tests by Stone Aerospace in June, 2015 on Matanuska Glacier, Alaska. The antennas are designed to operate inside ice while being immersed in a thin layer of surrounding low-conductivity melt water. Small holes in the corners of the cavities allow flooding of these cavities with the same melt-water thus allowing for quarter-wavelength cavity-backed reflection. Testing of the antenna array was first carried out by characterizing their operation inside a large ice block at the Stone Aerospace facility in Austin, TX. The complete radar system was then tested on the Matanuska glacier in Alaska, which is an effective Earth analog to Europan sub-surface exploration.

Uncertainty evaluation with increasing borehole drilling in subsurface hydrogeological explorations

NASA Astrophysics Data System (ADS)

Amano, K.; Ohyama, T.; Kumamoto, S.; Shimo, M.

2016-12-01

Quantities of drilling boreholes have been a difficult subject for field investigators in such as subsurface hydrogeological explorations. This problem becomes a bigger in heterogeneous formations or rock masses so we need to develop quantitative criteria for evaluating uncertainties during borehole investigations.To test an uncertainty reduction with increasing boreholes, we prepared a simple hydrogeological model and virtual hydraulic tests were carried out by using this model. The model consists of 125,000 elements of which hydraulic conductivities are generated randomly from the log-normal distribution in a 2-kilometer cube. Uncertainties were calculated by the difference of head distributions between the original model and the inchoate models made by virtual hydraulic test one by one.The results show the level and the variance of uncertainty are strongly correlated to the average and variance of the hydraulic conductivities. This kind of trends also could be seen in the actual field data obtained from the deep borehole investigations in Horonobe Town, northern Hokkaido, Japan. Here, a new approach using fractional bias (FB) and normalized mean square error (NMSE) for evaluating uncertainty characteristics will be introduced and the possibility of use as an indicator for decision making (i.e. to stop borehole drilling or to continue borehole drilling) in field investigations will be discussed.

Subsurface geology and oil and gas resources of Osage County, Oklahoma. Part 2, Townships 22 and 23 north, ranges 8 and 9 east

USGS Publications Warehouse

Kirk, C.T.; Jenkins, H.D.; Leatherock, Otto; Dillard, W.R.; Kennedy, L.E.; Bass, N.W.

1939-01-01

This report on the subsurface geology of Osage County, Okla., describes the structural features, the character of the oil- and gas-producing beds, and the localities where additional oil and gas may be found. It embodies a part of the results of a subsurface geologic investigation of the Osage Indian Reservation, which coincides in area with Osage County. The investigation was conducted by a field party of the Geological Survey of the United States Department of the Interior from 1934 to 1937 and involved the study of the records of about 17,000 wells that have been drilled in Osage County. Funds for the investigation were allotted to the Geological Survey by the Public Works Administration. The primary purpose of the examination was to obtain geologic data for use in the administration of the Indian lands. The results of the inquiry have shown that many localities in Osage County outside the present producing oil fields are worthy of prospecting for oil and gas and that additional oil and gas can be found also by exploring deeply buried beds in old producing fields.All townships in Osage County that contain many wells are described; the information furnished by such townships is ample for drawing detailed subsurface structure-contour maps. The descriptions of several contiguous townships are combined in separate reports, which are issued as parts of a single bulletin. No edition of the consolidated volume will be published, but the several parts can be bound together if desired.

Exploring the detection limits of infrared near-field microscopy regarding small buried structures and pushing them by exploiting superlens-related effects.

PubMed

Jung, Lena; Hauer, Benedikt; Li, Peining; Bornhöfft, Manuel; Mayer, Joachim; Taubner, Thomas

2016-03-07

We present a study on subsurface imaging with an infrared scattering-type scanning near-field optical microscope (s-SNOM). The depth-limitation for the visibility of gold nanoparticles with a diameter of 50 nm under Si 3 N 4 is determined to about 50 nm. We first investigate spot size and signal strength concerning their particle-size dependence for a dielectric cover layer with positive permittivity. The experimental results are confirmed by model calculations and a comparison to TEM images. In the next step, we investigate spectroscopically also the regime of negative permittivity of the capping layer and its influence on lateral resolution and signal strength in experiment and simulations. The explanation of this observation combines subsurface imaging and superlensing, and shows up limitations of the latter regarding small structure sizes.

Characterising the Architecture of New Zealand's Geothermal Structural Fluid Flow Networks Using Borehole Images

NASA Astrophysics Data System (ADS)

McNamara, David; Milicich, Sarah; Massiot, Cécile

2017-04-01

Borehole imaging has been used worldwide since the 1950's to capture vital geological information on the lithology, structure, and stress conditions of the Earth's subsurface. In New Zealand both acoustic and resistivity based borehole image logs are utilised to explore the geological nature of the basement and volcanic rocks that contain the country's unique geothermal reservoirs. Borehole image logs in wells from three geothermal fields in the Taupo Volcanic Zone (TVZ) provide the first, direct, subsurface, structural orientation measurements in New Zealand geothermal reservoir lithologies. While showing an overall structural pattern aligned to the regional tectonic trend, heterogeneities are observed that provide insight into the complexity of the structurally controlled, geothermal, fluid flow pathways. Analysis of imaged stress induced features informs us that the stress field orientation in the TVZ is also not homogenous, but is variable at a local scale.

Subsurface Exploration Methods for Soft Ground Rapid Transit Tunnels : Volume 2. Appendixes A-F.

DOT National Transportation Integrated Search

1976-04-01

This study assesses subsurface exploration methods with respect to their ability to provide adequate data for the construction of rapid transit, soft-ground bored and cut-and-cover tunnels. Geophysical and other exploration tools not now widely used ...

NEWTON - NEW portable multi-sensor scienTific instrument for non-invasive ON-site characterization of rock from planetary surface and sub-surfaces

NASA Astrophysics Data System (ADS)

Díaz-Michelena, M.; de Frutos, J.; Ordóñez, A. A.; Rivero, M. A.; Mesa, J. L.; González, L.; Lavín, C.; Aroca, C.; Sanz, M.; Maicas, M.; Prieto, J. L.; Cobos, P.; Pérez, M.; Kilian, R.; Baeza, O.; Langlais, B.; Thébault, E.; Grösser, J.; Pappusch, M.

2017-09-01

In space instrumentation, there is currently no instrument dedicated to susceptibly or complete magnetization measurements of rocks. Magnetic field instrument suites are generally vector (or scalar) magnetometers, which locally measure the magnetic field. When mounted on board rovers, the electromagnetic perturbations associated with motors and other elements make it difficult to reap the benefits from the inclusion of such instruments. However, magnetic characterization is essential to understand key aspects of the present and past history of planetary objects. The work presented here overcomes the limitations currently existing in space instrumentation by developing a new portable and compact multi-sensor instrument for ground breaking high-resolution magnetic characterization of planetary surfaces and sub-surfaces. This new technology introduces for the first time magnetic susceptometry (real and imaginary parts) as a complement to existing compact vector magnetometers for planetary exploration. This work aims to solve the limitations currently existing in space instrumentation by means of providing a new portable and compact multi-sensor instrument for use in space, science and planetary exploration to solve some of the open questions on the crustal and more generally planetary evolution within the Solar System.

The Correlation between Radon Emission Concentration and Subsurface Geological Condition

NASA Astrophysics Data System (ADS)

Kuntoro, Yudi; Setiawan, Herru L.; Wijayanti, Teni; Haerudin, Nandi

2018-03-01

Exploration activities with standard methods have already encountered many obstacles in the field. Geological survey is often difficult to find outcrop because they are covered by vegetation, alluvial layer or as a result of urban development and housing. Seismic method requires a large expense and licensing in the use of dynamite is complicated. Method of gravity requires the operator to go back (looping) to the starting point. Given some of these constraints, therefore it needs a solution in the form of new method that can work more efficiently with less cost. Several studies in various countries have shown a correlation between the presence of hydrocarbons and Radon gas concentration in the earth surface. By utilizing the properties of Radon that can migrate to the surface, the value of Radon concentration in the surface is suggested to provide information about the subsurface structure condition. Radon is the only radioactive substance that gas-phased at atmospheric temperature. It is very abundant in the earth mantle. The vast differences of temperatures and pressures between the mantle and the earth crust cause the convection flow toward earth surface. Radon in gas phase will be carried by convection flow to the surface. The quantity of convection currents depend on the porosity and permeability of rocks where Radon travels within, so that Radon concentration in the earth surface delineates the porosity and permeability of subsurface rock layers. Some measurements were carried out at several locations with various subsurface geological conditions, including proven oil fields, proven geothermal field, and frontier area as a comparison. These measurements show that the average and the background concentration threshold in the proven oil field (11,200 Bq/m3) and proven geothermal field (7,820 Bq/m3) is much higher than the quantity in frontier area (329 and 1,620 Bq/m3). Radon concentration in the earth surface is correlated with the presence of geological faults. Peak concentrations of Radon takes place along the fault.

Quantifying shallow subsurface water and heat dynamics using coupled hydrological-thermal-geophysical inversion

DOE PAGES

Tran, Anh Phuong; Dafflon, Baptiste; Hubbard, Susan S.; ...

2016-04-25

Improving our ability to estimate the parameters that control water and heat fluxes in the shallow subsurface is particularly important due to their strong control on recharge, evaporation and biogeochemical processes. The objectives of this study are to develop and test a new inversion scheme to simultaneously estimate subsurface hydrological, thermal and petrophysical parameters using hydrological, thermal and electrical resistivity tomography (ERT) data. The inversion scheme-which is based on a nonisothermal, multiphase hydrological model-provides the desired subsurface property estimates in high spatiotemporal resolution. A particularly novel aspect of the inversion scheme is the explicit incorporation of the dependence of themore » subsurface electrical resistivity on both moisture and temperature. The scheme was applied to synthetic case studies, as well as to real datasets that were autonomously collected at a biogeochemical field study site in Rifle, Colorado. At the Rifle site, the coupled hydrological-thermal-geophysical inversion approach well predicted the matric potential, temperature and apparent resistivity with the Nash-Sutcliffe efficiency criterion greater than 0.92. Synthetic studies found that neglecting the subsurface temperature variability, and its effect on the electrical resistivity in the hydrogeophysical inversion, may lead to an incorrect estimation of the hydrological parameters. The approach is expected to be especially useful for the increasing number of studies that are taking advantage of autonomously collected ERT and soil measurements to explore complex terrestrial system dynamics.« less

Geophysical exploration with audio frequency magnetic fields

NASA Astrophysics Data System (ADS)

Labson, V. F.

1985-12-01

Experience with the Audio Frequency Magnetic (AFMAG) method has demonstrated that an electromagnetic exploration system using the Earth's natural audiofrequency magnetic fields as an energy source, is capable of mapping subsurface electrical structure in the upper kilometer of the Earth's crust. The limitations are resolved by adapting the tensor analysis and remote reference noise bias removal techniques from the geomagnetic induction and magnetotelluric methods to the computation of the tippers. After a through spectral study of the natural magnetic fields, lightweight magnetic field sensors, capable of measuring the magnetic field throughout the year were designed. A digital acquisition and processing sytem, with the ability to provide audiofrequency tipper results in the field, was then built to complete the apparatus. The new instrumetnation was used in a study of the Mariposa, California site previously mapped with AFMAG. The usefulness of natural magnetic field data in mapping an electrical conductive body was again demonstrated. Several field examples are used to demonstrate that the proposed procedure yields reasonable results.

Issues in subsurface exploration of ice sheets

NASA Technical Reports Server (NTRS)

French, L.; Carsey, F.; Zimmerman, W.

2000-01-01

Exploration of the deep subsurface ice sheets of Earth, Mars, Europa, and Titan has become a major consideration in addressing scientific objectives in climate change, extremophile biology, exobiology,chemical weathering, planetary evolution and ice dynamics.

Fast-Turnoff Transient Electro-Magnetic (TEM) geophysical survey in the Peña de Hierro ("Berg of Iron") field area of the Mars Analog Research and Technology Experiment (MARTE)

NASA Astrophysics Data System (ADS)

Jernsletten, J. A.

2004-12-01

This report describes the outcome of a Fast-Turnoff Transient Electro-Magnetic (TEM) geophysical survey carried out in the Peña de Hierro ("Berg of Iron") field area of the Mars Analog Research and Technology Experiment (MARTE), during May and June of 2003. The MARTE Peña de Hierro field area is located between the towns of Rio Tinto and Nerva in the Andalucia region of Spain. It is about one hour drive West of the city of Sevilla, and also about one hour drive North of Huelva. The high concentration of dissolved iron (and smaller amounts of other metals) in the very acidic water in the Rio Tinto area gives the water its characteristic wine red color, and also means that the water is highly conductive, and such an acidic and conductive fluid is highly suited for exploration by electromagnetic methods. This naturally acidic environment is maintained by bacteria in the groundwater and it is these bacteria that are the main focus of the MARTE project overall, and of this supporting geophysical work. It is the goal of this study to be able to map the subsurface extent of the high conductivity (low resistivity) levels, and thus by proxy the subsurface extent of the acidic groundwater and the bacteria populations. In so doing, the viability of using electromagnetic methods for mapping these subsurface metal-rich water bodies is also examined and demonstrated, and the geophysical data will serve to support drilling efforts. The purpose of this field survey was an initial effort to map certain conductive features in the field area, in support of the drilling operations that are central to the MARTE project. These conductive features include the primary target of exploration for MARTE, the very conductive acidic groundwater in the area (which is extremely rich in metals). Other conductive features include the pyretic ore bodies in the area, as well as extensive mine tailings piles.

The Serpentinite Subsurface Microbiome

NASA Astrophysics Data System (ADS)

Schrenk, M. O.; Nelson, B. Y.; Brazelton, W. J.

2011-12-01

Microbial habitats hosted in ultramafic rocks constitute substantial, globally-distributed portions of the subsurface biosphere, occurring both on the continents and beneath the seafloor. The aqueous alteration of ultramafics, in a process known as serpentinization, creates energy rich, high pH conditions, with low concentrations of inorganic carbon which place fundamental constraints upon microbial metabolism and physiology. Despite their importance, very few studies have attempted to directly access and quantify microbial activities and distributions in the serpentinite subsurface microbiome. We have initiated microbiological studies of subsurface seeps and rocks at three separate continental sites of serpentinization in Newfoundland, Italy, and California and compared these results to previous analyses of the Lost City field, near the Mid-Atlantic Ridge. In all cases, microbial cell densities in seep fluids are extremely low, ranging from approximately 100,000 to less than 1,000 cells per milliliter. Culture-independent analyses of 16S rRNA genes revealed low-diversity microbial communities related to Gram-positive Firmicutes and hydrogen-oxidizing bacteria. Interestingly, unlike Lost City, there has been little evidence for significant archaeal populations in the continental subsurface to date. Culturing studies at the sites yielded numerous alkaliphilic isolates on nutrient-rich agar and putative iron-reducing bacteria in anaerobic incubations, many of which are related to known alkaliphilic and subsurface isolates. Finally, metagenomic data reinforce the culturing results, indicating the presence of genes associated with organotrophy, hydrogen oxidation, and iron reduction in seep fluid samples. Our data provide insight into the lifestyles of serpentinite subsurface microbial populations and targets for future quantitative exploration using both biochemical and geochemical approaches.

A Search for Freshwater in the Saline Aquifers of Coastal Bangladesh

NASA Astrophysics Data System (ADS)

Peters, C.; Hornberger, G. M.

2017-12-01

Can we locate pockets of freshwater amidst brackish groundwater in remote villages in Bangladesh? This study explores what we can infer about local groundwater-surface water (GW-SW) interactions in the polders of coastal Bangladesh. In this underdeveloped region, the shallow groundwater is primarily brackish with unpredictable apportioning of freshwater pockets. We use transects of piezometers, cores, electromagnetic induction, and water chemistry surveys to explore two sources of potential fresh groundwater: (1) tidal channel-aquifer exchange and (2) meteoric recharge. Freshwater is difficult to find due to disparate subsurface lithology, asymmetrical tidal dynamics, extreme seasonal fluctuations in rainfall, and limited field data. Observations suggest substantial lateral variability in shallow subsurface conductivity profiles as well as tidal pressure signals in piezometers. Nevertheless, active exchange of freshwater may be limited due to low permeability of banks and surface sediments limits. Small scale heterogeneity in delta formation likely caused much of the groundwater salinity variation. Without adequate ground truthing of groundwater quality, the ability to deduce the exact location of freshwater pockets may be restricted.

Properties of Subsurface Soil Cores from Four Geologic Provinces Surrounding Mars Desert Research Station, Utah: Characterizing Analog Martian Soil in a Human Exploration Scenario

NASA Technical Reports Server (NTRS)

Stoker, C. R.; Clarke, J. D. A.; Direito, S.; Foing, B.

2011-01-01

The DOMEX program is a NASA-MMAMA funded project featuring simulations of human crews on Mars focused on science activities that involve collecting samples from the subsurface using both manual and robotic equipment methods and analyzing them in the field and post mission. A crew simulating a human mission to Mars performed activities focused on subsurface science for 2 weeks in November 2009 at Mars Desert Research Station near Hanksville, Utah --an important chemical and morphological Mars analog site. Activities performed included 1) survey of the area to identify geologic provinces, 2) obtaining soil and rock samples from each province and characterizing their mineralogy, chemistry, and biology; 3) site selection and reconnaissance for a future drilling mission; 4) deployment and testing of Mars Underground Mole, a percussive robotic soil sampling device; and 5) recording and analyzing how crew time was used to accomplish these tasks. This paper summarizes results from analysis of soil cores

Frequency domain electromagnetic induction survey in the intertidal zone: Limitations of low-induction-number and depth of exploration

NASA Astrophysics Data System (ADS)

Delefortrie, Samuël; Saey, Timothy; Van De Vijver, Ellen; De Smedt, Philippe; Missiaen, Tine; Demerre, Ine; Van Meirvenne, Marc

2014-01-01

Subsurface investigation in the Belgian intertidal zone is severely complicated due to high heterogeneity and tides. Near-surface geophysical techniques can offer assistance since they allow fast surveying and collection of high spatial density data and frequency domain electromagnetic induction (EMI) was chosen for archaeological prospection on the Belgian shore. However, in the intertidal zone the effects of extreme salinity compromise validity of low-induction-number (LIN) approximated EMI data. In this paper, the effects of incursion of seawater on multi-receiver EMI data are investigated by means of survey results, field observations, cone penetration tests and in-situ electrical conductivity measurements. The consequences of LIN approximation breakdown were researched. Reduced depth of investigation of the quadrature-phase (Qu) response and a complex interpretation of the in-phase response were confirmed. Nonetheless, a high signal-to-noise ratio of the Qu response and viable data with regard to shallow subsurface investigation were also evidenced, allowing subsurface investigation in the intertidal zone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

This case history discusses the exploration methods used at the Momotombo Geothermal Field in western Nicaragua, and evaluates their contributions to the development of the geothermal field models. Subsequent reservoir engineering has not been synthesized or evaluated. A geothermal exploration program was started in Nicaragua in 1966 to discover and delineate potential geothermal reservoirs in western Nicaragua. Exploration began at the Momotombo field in 1970 using geological, geochemical, and geophysical methods. A regional study of thermal manifestations was undertaken and the area on the southern flank of Volcan Momotombo was chosen for more detailed investigation. Subsequent exploration by various consultantsmore » produced a number of geotechnical reports on the geology, geophysics, and geochemistry of the field as well as describing production well drilling. Geological investigations at Momotombo included photogeology, field mapping, binocular microscope examination of cuttings, and drillhole correlations. Among the geophysical techniques used to investigate the field sub-structure were: Schlumberger and electromagnetic soundings, dipole mapping and audio-magnetotelluric surveys, gravity and magnetic measurements, frequency domain soundings, self-potential surveys, and subsurface temperature determinations. The geochemical program analyzed the thermal fluids of the surface and in the wells. This report presents the description and results of exploration methods used during the investigative stages of the Momotombo Geothermal Field. A conceptual model of the geothermal field was drawn from the information available at each exploration phase. The exploration methods have been evaluated with respect to their contributions to the understanding of the field and their utilization in planning further development. Our principal finding is that data developed at each stage were not sufficiently integrated to guide further work at the field, causing inefficient use of resources.« less

Play-fairway analysis for geothermal exploration: Examples from the Great Basin, western USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siler, Drew L; Faulds, James E

2013-10-27

Elevated permeability within fault systems provides pathways for circulation of geothermal fluids. Future geothermal development depends on precise and accurate location of such fluid flow pathways in order to both accurately assess geothermal resource potential and increase drilling success rates. The collocation of geologic characteristics that promote permeability in a given geothermal system define the geothermal ‘fairway’, the location(s) where upflow zones are probable and where exploration efforts including drilling should be focused. We define the geothermal fairway as the collocation of 1) fault zones that are ideally oriented for slip or dilation under ambient stress conditions, 2) areas withmore » a high spatial density of fault intersections, and 3) lithologies capable of supporting dense interconnected fracture networks. Areas in which these characteristics are concomitant with both elevated temperature and fluids are probable upflow zones where economic-scale, sustainable temperatures and flow rates are most likely to occur. Employing a variety of surface and subsurface data sets, we test this ‘play-fairway’ exploration methodology on two Great Basin geothermal systems, the actively producing Brady’s geothermal system and a ‘greenfield’ geothermal prospect at Astor Pass, NV. These analyses, based on 3D structural and stratigraphic framework models, reveal subsurface characteristics about each system, well beyond the scope of standard exploration methods. At Brady’s, the geothermal fairways we define correlate well with successful production wells and pinpoint several drilling targets for maintaining or expanding production in the field. In addition, hot-dry wells within the Brady’s geothermal field lie outside our defined geothermal fairways. At Astor Pass, our play-fairway analysis provides for a data-based conceptual model of fluid flow within the geothermal system and indicates several targets for exploration drilling.« less

The Hidden Magnetic Field of the Young Neutron Star in Kesteven 79

NASA Astrophysics Data System (ADS)

Shabaltas, Natalia; Lai, Dong

2012-04-01

Recent observations of the central compact object in the Kesteven 79 supernova remnant show that this neutron star (NS) has a weak dipole magnetic field (a few × 1010 G) but an anomalously large (~64%) pulse fraction in its surface X-ray emission. We explore the idea that a substantial sub-surface magnetic field exists in the NS crust, which produces diffuse hot spots on the stellar surface due to anisotropic heat conduction, and gives rise to the observed X-ray pulsation. We develop a general-purpose method, termed "Temperature Template with Full Transport" (TTFT), that computes the synthetic pulse profile of surface X-ray emission from NSs with arbitrary magnetic field and surface temperature distributions, taking into account magnetic atmosphere opacities, beam pattern, vacuum polarization, and gravitational light bending. We show that a crustal toroidal magnetic field of order a few × 1014 G or higher, varying smoothly across the crust, can produce sufficiently distinct surface hot spots to generate the observed pulse fraction in the Kes 79 NS. This result suggests that substantial sub-surface magnetic fields, much stronger than the "visible" dipole fields, may be buried in the crusts of some young NSs, and such hidden magnetic fields can play an important role in their observational manifestations. The general TTFT tool we have developed can also be used for studying radiation from other magnetic NSs.

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

NASA Astrophysics Data System (ADS)

Payler, Samuel J.; Biddle, Jennifer F.; Coates, Andrew J.; Cousins, Claire R.; Cross, Rachel E.; Cullen, David C.; Downs, Michael T.; Direito, Susana O. L.; Edwards, Thomas; Gray, Amber L.; Genis, Jac; Gunn, Matthew; Hansford, Graeme M.; Harkness, Patrick; Holt, John; Josset, Jean-Luc; Li, Xuan; Lees, David S.; Lim, Darlene S. S.; McHugh, Melissa; McLuckie, David; Meehan, Emma; Paling, Sean M.; Souchon, Audrey; Yeoman, Louise; Cockell, Charles S.

2017-04-01

The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research - MINe Analog Research (MINAR). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small-scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator, Close-Up Imager, Raman spectrometer, Small Planetary Linear Impulse Tool, Ultrasonic drill and handheld X-ray diffraction (XRD). We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimetre to metre scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining.

In-Tank Processing (ITP) Geotechnical Summary Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cumbest, R.J.

A geotechnical investigation has been completed for the In Tank Processing Facility (ITP) which consists of buildings 241-96H and 241-32H; and Tanks 241-948H, 241-949H, 241-950H, and 241-951H. The investigation consisted of a literature search for relevant technical data, field explorations, field and laboratory testing, and analyses. This document presents a summary of the scope and results to date of the investigations and engineering analyses for these facilities. A final geotechnical report, which will include a more detailed discussion and all associated boring logs, laboratory test results, and analyses will be issued in October 1994.The purpose of the investigation is tomore » obtain geotechnical information to evaluate the seismic performance of the foundation materials and embankme nts under and around the ITP. The geotechnical engineering objectives of the investigation are to: 1) define the subsurface stratigraphy, 2) obtain representative engineering properties of the subsurface materials, 3) assess the competence of the subsurface materials under static and dynamic loads, 4) derive properties for seismic soil-structure interaction analysis, 5) evaluate the areal and vertical extent of horizons that might cause dynamic settlement or instability, and 6) determine settlement at the foundation level of the tanks.« less

Final Project Report: Imaging Fault Zones Using a Novel Elastic Reverse-Time Migration Imaging Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Lianjie; Chen, Ting; Tan, Sirui

Imaging fault zones and fractures is crucial for geothermal operators, providing important information for reservoir evaluation and management strategies. However, there are no existing techniques available for directly and clearly imaging fault zones, particularly for steeply dipping faults and fracture zones. In this project, we developed novel acoustic- and elastic-waveform inversion methods for high-resolution velocity model building. In addition, we developed acoustic and elastic reverse-time migration methods for high-resolution subsurface imaging of complex subsurface structures and steeply-dipping fault/fracture zones. We first evaluated and verified the improved capabilities of our newly developed seismic inversion and migration imaging methods using synthetic seismicmore » data. Our numerical tests verified that our new methods directly image subsurface fracture/fault zones using surface seismic reflection data. We then applied our novel seismic inversion and migration imaging methods to a field 3D surface seismic dataset acquired at the Soda Lake geothermal field using Vibroseis sources. Our migration images of the Soda Lake geothermal field obtained using our seismic inversion and migration imaging algorithms revealed several possible fault/fracture zones. AltaRock Energy, Inc. is working with Cyrq Energy, Inc. to refine the geologic interpretation at the Soda Lake geothermal field. Trenton Cladouhos, Senior Vice President R&D of AltaRock, was very interested in our imaging results of 3D surface seismic data from the Soda Lake geothermal field. He planed to perform detailed interpretation of our images in collaboration with James Faulds and Holly McLachlan of University of Nevada at Reno. Using our high-resolution seismic inversion and migration imaging results can help determine the optimal locations to drill wells for geothermal energy production and reduce the risk of geothermal exploration.« less

Complete Subsurface Elemental Composition Measurements With PING

NASA Technical Reports Server (NTRS)

Parsons, A. M.

2012-01-01

The Probing In situ with Neutrons and Gamma rays (PING) instrument will measure the complete bulk elemental composition of the subsurface of Mars as well as any other solid planetary body. PING can thus be a highly effective tool for both detailed local geochemistry science investigations and precision measurements of Mars subsurface reSOurces in preparation for future human exploration. As such, PING is thus fully capable of meeting a majority of both ncar and far term elements in Challenge #1 presented for this conference. Measuring the ncar subsurface composition of Mars will enable many of the MEPAG science goals and will be key to filling an important Strategic Knowledge Gap with regard to In situ Resources Utilization (ISRU) needs for human exploration. [1, 2] PING will thus fill an important niche in the Mars Exploration Program.

Electrical Conductivity Imaging Using Controlled Source Electromagnetics for Subsurface Characterization

NASA Astrophysics Data System (ADS)

Miller, C. R.; Routh, P. S.; Donaldson, P. R.

2004-05-01

Controlled Source Audio-Frequency Magnetotellurics (CSAMT) is a frequency domain electromagnetic (EM) sounding technique. CSAMT typically uses a grounded horizontal electric dipole approximately one to two kilometers in length as a source. Measurements of electric and magnetic field components are made at stations located ideally at least four skin depths away from the transmitter to approximate plane wave characteristics of the source. Data are acquired in a broad band frequency range that is sampled logarithmically from 0.1 Hz to 10 kHz. The usefulness of CSAMT soundings is to detect and map resistivity contrasts in the top two to three km of the Earth's surface. Some practical applications that CSAMT soundings have been used for include mapping ground water resources; mineral/precious metals exploration; geothermal reservoir mapping and monitoring; petroleum exploration; and geotechnical investigations. Higher frequency data can be used to image shallow features and lower frequency data are sensitive to deeper structures. We have a 3D CSAMT data set consisting of phase and amplitude measurements of the Ex and Hy components of the electric and magnetic fields respectively. The survey area is approximately 3 X 5 km. Receiver stations are situated 50 meters apart along a total of 13 lines with 8 lines bearing approximately N60E and the remainder of the lines oriented orthogonal to these 8 lines. We use an unconstrained Gauss-Newton method with positivity to invert the data. Inversion results will consist of conductivity versus depth profiles beneath each receiver station. These 1D profiles will be combined into a 3D subsurface conductivity image. We will include our interpretation of the subsurface conductivity structure and quantify the uncertainties associated with this interpretation.

Geochemical and Mineralogical Analyses of Cold Spring Deposits at Borup Fiord Pass, a Sulfur-Dominated Arctic Analog for Planetary Environments on Mars and Europa

NASA Astrophysics Data System (ADS)

Lau, Graham Elliot

Sulfur is one of the most ubiquitous elements in the universe and one of those that is crucial for life, as we know it. This graduate dissertation presents the culmination of work conducted to better understand biological and geochemical processes related to sulfur cycling at a sulfur-dominated field site in the Canadian High Arctic. This site, situated in a valley called Borup Fiord Pass, provides a unique environment where sulfide-rich fluids emerge from a glacier and form large deposits of ice that become covered in elemental sulfur. The role of biology is compelling and yet challenging to define in each step of sulfur cycling at Borup Fiord pass, whether one considers the origin of the sulfide (presumed biological sulfate reduction in the subsurface) or one focuses on the processes driving sulfur oxidation and stabilization at the glacier's surface. This dissertation presents results from a field expedition in 2014 as well as detailed mineralogical and spectroscopic analyses of sulfur-rich materials returned from the field. The importance of sulfur and carbonate minerals at this site is considered. Also, analyses of materials within pyrite alteration features in the valley are explored. These features appear to represent emplaced subsurface sulfide ores, which have been subsequently leached near the surface, forming gossanous structures. The geochemistry and mineralogy of these features is explored, as well as is their potential to serve as analogs for the exploration of Mars. The dissertation then concludes with some consideration of potential future work to be considered as well as a recapitulation of the current state of knowledge of processes at Borup Fiord Pass.

Robotic and Human-Tended Collaborative Drilling Automation for Subsurface Exploration

NASA Technical Reports Server (NTRS)

Glass, Brian; Cannon, Howard; Stoker, Carol; Davis, Kiel

2005-01-01

Future in-situ lunar/martian resource utilization and characterization, as well as the scientific search for life on Mars, will require access to the subsurface and hence drilling. Drilling on Earth is hard - an art form more than an engineering discipline. Human operators listen and feel drill string vibrations coming from kilometers underground. Abundant mass and energy make it possible for terrestrial drilling to employ brute-force approaches to failure recovery and system performance issues. Space drilling will require intelligent and autonomous systems for robotic exploration and to support human exploration. Eventual in-situ resource utilization will require deep drilling with probable human-tended operation of large-bore drills, but initial lunar subsurface exploration and near-term ISRU will be accomplished with lightweight, rover-deployable or standalone drills capable of penetrating a few tens of meters in depth. These lightweight exploration drills have a direct counterpart in terrestrial prospecting and ore-body location, and will be designed to operate either human-tended or automated. NASA and industry now are acquiring experience in developing and building low-mass automated planetary prototype drills to design and build a pre-flight lunar prototype targeted for 2011-12 flight opportunities. A successful system will include development of drilling hardware, and automated control software to operate it safely and effectively. This includes control of the drilling hardware, state estimation of both the hardware and the lithography being drilled and state of the hole, and potentially planning and scheduling software suitable for uncertain situations such as drilling. Given that Humans on the Moon or Mars are unlikely to be able to spend protracted EVA periods at a drill site, both human-tended and robotic access to planetary subsurfaces will require some degree of standalone, autonomous drilling capability. Human-robotic coordination will be important, either between a robotic drill and humans on Earth, or a human-tended drill and its visiting crew. The Mars Analog Rio Tinto Experiment (MARTE) is a current project that studies and simulates the remote science operations between an automated drill in Spain and a distant, distributed human science team. The Drilling Automation for Mars Exploration (DAME) project, by contrast: is developing and testing standalone automation at a lunar/martian impact crater analog site in Arctic Canada. The drill hardware in both projects is a hardened, evolved version of the Advanced Deep Drill (ADD) developed by Honeybee Robotics for the Mars Subsurface Program. The current ADD is capable of 20m, and the DAME project is developing diagnostic and executive software for hands-off surface operations of the evolved version of this drill. The current drill automation architecture being developed by NASA and tested in 2004-06 at analog sites in the Arctic and Spain will add downhole diagnosis of different strata, bit wear detection, and dynamic replanning capabilities when unexpected failures or drilling conditions are discovered in conjunction with simulated mission operations and remote science planning. The most important determinant of future 1unar and martian drilling automation and staffing requirements will be the actual performance of automated prototype drilling hardware systems in field trials in simulated mission operations. It is difficult to accurately predict the level of automation and human interaction that will be needed for a lunar-deployed drill without first having extensive experience with the robotic control of prototype drill systems under realistic analog field conditions. Drill-specific failure modes and software design flaws will become most apparent at this stage. DAME will develop and test drill automation software and hardware under stressful operating conditions during several planned field campaigns. Initial results from summer 2004 tests show seven identifi distinct failure modes of the drill: cuttings-removal issues with low-power drilling into permafrost, and successful steps at executive control and initial automation.

Modeling the hydrogeophysical response of lake talik evolution

USGS Publications Warehouse

Minsley, Burke J.; Wellman, Tristan; Walvoord, Michelle Ann; Revil, Andre

2014-01-01

Geophysical methods provide valuable information about subsurface permafrost and its relation to dynamic hydrologic systems. Airborne electromagnetic data from interior Alaska are used to map the distribution of permafrost, geological features, surface water, and groundwater. To validate and gain further insight into these field datasets, we also explore the geophysical response to hydrologic simulations of permafrost evolution by implementing a physical property relationship that connects geology, temperature, and ice saturation to changes in electrical properties.

In-situ Planetary Subsurface Imaging System

NASA Astrophysics Data System (ADS)

Song, W.; Weber, R. C.; Dimech, J. L.; Kedar, S.; Neal, C. R.; Siegler, M.

2017-12-01

Geophysical and seismic instruments are considered the most effective tools for studying the detailed global structures of planetary interiors. A planet's interior bears the geochemical markers of its evolutionary history, as well as its present state of activity, which has direct implications to habitability. On Earth, subsurface imaging often involves massive data collection from hundreds to thousands of geophysical sensors (seismic, acoustic, etc) followed by transfer by hard links or wirelessly to a central location for post processing and computing, which will not be possible in planetary environments due to imposed mission constraints on mass, power, and bandwidth. Emerging opportunities for geophysical exploration of the solar system from Venus to the icy Ocean Worlds of Jupiter and Saturn dictate that subsurface imaging of the deep interior will require substantial data reduction and processing in-situ. The Real-time In-situ Subsurface Imaging (RISI) technology is a mesh network that senses and processes geophysical signals. Instead of data collection then post processing, the mesh network performs the distributed data processing and computing in-situ, and generates an evolving 3D subsurface image in real-time that can be transmitted under bandwidth and resource constraints. Seismic imaging algorithms (including traveltime tomography, ambient noise imaging, and microseismic imaging) have been successfully developed and validated using both synthetic and real-world terrestrial seismic data sets. The prototype hardware system has been implemented and can be extended as a general field instrumentation platform tailored specifically for a wide variety of planetary uses, including crustal mapping, ice and ocean structure, and geothermal systems. The team is applying the RISI technology to real off-world seismic datasets. For example, the Lunar Seismic Profiling Experiment (LSPE) deployed during the Apollo 17 Moon mission consisted of four geophone instruments spaced up to 100 meters apart, which in essence forms a small aperture seismic network. A pattern recognition technique based on Hidden Markov Models was able to characterize this dataset, and we are exploring how the RISI technology can be adapted for this dataset.

A stochastic approach for model reduction and memory function design in hydrogeophysical inversion

NASA Astrophysics Data System (ADS)

Hou, Z.; Kellogg, A.; Terry, N.

2009-12-01

Geophysical (e.g., seismic, electromagnetic, radar) techniques and statistical methods are essential for research related to subsurface characterization, including monitoring subsurface flow and transport processes, oil/gas reservoir identification, etc. For deep subsurface characterization such as reservoir petroleum exploration, seismic methods have been widely used. Recently, electromagnetic (EM) methods have drawn great attention in the area of reservoir characterization. However, considering the enormous computational demand corresponding to seismic and EM forward modeling, it is usually a big problem to have too many unknown parameters in the modeling domain. For shallow subsurface applications, the characterization can be very complicated considering the complexity and nonlinearity of flow and transport processes in the unsaturated zone. It is warranted to reduce the dimension of parameter space to a reasonable level. Another common concern is how to make the best use of time-lapse data with spatial-temporal correlations. This is even more critical when we try to monitor subsurface processes using geophysical data collected at different times. The normal practice is to get the inverse images individually. These images are not necessarily continuous or even reasonably related, because of the non-uniqueness of hydrogeophysical inversion. We propose to use a stochastic framework by integrating minimum-relative-entropy concept, quasi Monto Carlo sampling techniques, and statistical tests. The approach allows efficient and sufficient exploration of all possibilities of model parameters and evaluation of their significances to geophysical responses. The analyses enable us to reduce the parameter space significantly. The approach can be combined with Bayesian updating, allowing us to treat the updated ‘posterior’ pdf as a memory function, which stores all the information up to date about the distributions of soil/field attributes/properties, then consider the memory function as a new prior and generate samples from it for further updating when more geophysical data is available. We applied this approach for deep oil reservoir characterization and for shallow subsurface flow monitoring. The model reduction approach reliably helps reduce the joint seismic/EM/radar inversion computational time to reasonable levels. Continuous inversion images are obtained using time-lapse data with the “memory function” applied in the Bayesian inversion.

Subsurface lateral preferential flow network revealed by time-lapse ground-penetrating radar in a hillslope

NASA Astrophysics Data System (ADS)

Guo, Li; Chen, Jin; Lin, Henry

2014-12-01

Subsurface lateral preferential flow (LPF) has been observed to contribute substantially to hillslope and catchment runoff. However, the complex nature of LPF and the lack of an appropriate investigation method have hindered direct LPF observation in the field. Thus, the initiation, persistence, and dynamics of LPF networks remain poorly understood. This study explored the application of time-lapse ground-penetrating radar (GPR) together with an artificial infiltration to shed light on the nature of LPF and its dynamics in a hillslope. Based on our enhanced field experimental setup and carefully refined GPR data postprocessing algorithms, we developed a new protocol to reconstruct LPF networks with centimeter resolution. This is the first time that a detailed LPF network and its dynamics have been revealed noninvasively along a hillslope. Real-time soil water monitoring and field soil investigation confirmed the locations of LPF mapped by time-lapse GPR surveys. Our results indicated the following: (1) Increased spatial variations of radar signals after infiltration suggested heterogeneous soil water changes within the studied soil, which reflected the generation and dynamics of LPF; (2) Two types of LPF networks were identified, the network at the location of soil permeability contrasts and that formed via a series of connected preferential flow paths; and (3) The formation and distribution of LPF networks were influenced by antecedent soil water condition. Overall, this study demonstrates clearly that carefully designed time-lapse GPR surveys with enhanced data postprocessing offer a practical and nondestructive way of mapping LPF networks in the field, thereby providing a potentially significant enhancement in our ability to study complex subsurface flow processes across the landscape.

A Combined Study of Photospheric Magnetic and Current Helicities and Subsurface Kinetic Helicities of Solar Active Regions during 2006-2013

NASA Astrophysics Data System (ADS)

Seligman, D.; Petrie, G. J. D.; Komm, R.

2014-11-01

We compare the average photospheric current helicity Hc , photospheric twist parameter α (a well-known proxy for the full relative magnetic helicity), and subsurface kinetic helicity Hk for 194 active regions observed between 2006-2013. We use 2440 Hinode photospheric vector magnetograms, and the corresponding subsurface fluid velocity data derived from GONG (2006-2012) and Helioseismic and Magnetic Imager (2010-2013) dopplergrams. We find a significant hemispheric bias in all three parameters. The subsurface kinetic helicity is preferentially positive in the southern hemisphere and negative in the northern hemisphere. The photospheric current helicity and the α parameter have the same bias for strong fields (|B| > 1000 G) and no significant bias for weak fields (100 G <|B| < 500 G). We find no significant region-by-region correlation between the subsurface kinetic helicity and either the strong-field current helicity or α. Subsurface fluid motions of a given handedness correspond to photospheric helicities of both signs in approximately equal numbers. However, common variations appear in annual averages of these quantities over all regions. Furthermore, in a subset of 77 regions, we find significant correlations between the temporal profiles of the subsurface and photospheric helicities. In these cases, the sign of the linear correlation coefficient matches the sign relationship between the helicities, indicating that the photospheric magnetic field twist is sensitive to the twisting motions below the surface.

The subsurface record for the Anthropocene based on the global analysis of deep wells

NASA Astrophysics Data System (ADS)

Rose, K.

2016-12-01

While challenges persist in the characterization of Earth's subsurface, over two centuries of exploration resulting in more than six million deep wellbores, offer insights into these systems. Characteristics of the subsurface vary and can be analyzed on a variety of spatial scales using geospatial tools and methods. Characterization and prediction of subsurface properties, such as depth, thickness, porosity, permeability, pressure and temperature, are important for models and interpretations of the subsurface. Subsurface studies contribute to insights and understanding of natural system but also enable predictions and assessments of subsurface resources and support environmental and geohazard assessments. As the geo-data science landscape shifts, becoming more open, there are increasing opportunities to fill knowledge gaps, mine large, interrelated datasets, and develop innovative methods to improve our understanding of the subsurface and the impacts of its exploration. In this study, a global dataset of more than 6,000,000 deep subsurface wells has been assembled using ArcGIS and Access, which reflects to a first order, the cumulative representation of over two centuries of drilling. Wellbore data, in general represent the only portal for direct measurement and characterization of deep subsurface properties. As human engineering of the subsurface evolves from a focus on hydrocarbon resource development to include subsurface waste product disposal (e.g. CO2, industrial waste, etc) and production of other deep subsurface resources, such as heat and water resources, there is the increasing need to improve characterization techniques and understand local and global ramifications of anthropogenic interaction with the subsurface. Data and geospatial analyses are reviewed to constrain the extent to which human interactions, not just with Earth's surface systems, atmospheric and geologic, but subsurface systems will result in an enduring signature of human influences on the planet. Specifically, the extent and enduring signature of subsurface interactions with the planet, utilizing the four-dimensional, spatial and temporal, record for known deep wellbores is utilized.

Importance of solar subsurface heating in ocean general circulation models

NASA Astrophysics Data System (ADS)

Rochford, Peter A.; Kara, A. Birol; Wallcraft, Alan J.; Arnone, Robert A.

2001-12-01

The importance of subsurface heating on surface mixed layer properties in an ocean general circulation model (OGCM) is examined using attenuation of solar irradiance with depth below the ocean surface. The depth-dependent attenuation of subsurface heating is given by global monthly mean fields for the attenuation of photosynthetically available radiation (PAR), kPAR. These global fields of kPAR are derived from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data on the spectral diffuse attenuation coefficient at 490 nm (k490), and have been processed to have the smoothly varying and continuous coverage necessary for use in OGCM applications. These monthly fields provide the first complete global data sets of subsurface optical fields that can be used for OGCM applications of subsurface heating and bio-optical processes. The effect on global OGCM prediction of sea surface temperature (SST) and surface mixed layer depth (MLD) is examined when solar heating, as given by monthly mean kPAR and PAR fields, is included in the model. It is found that subsurface heating yields a marked increase in the SST predictive skill of the OGCM at low latitudes. No significant improvement in MLD predictive skill is obtained when including subsurface heating. Use of the monthly mean kPAR produces an SST decrease of up to 0.8°C and a MLD increase of up to only 4-5 m for climatological surface forcing, with this primarily confined to the equatorial regions. Remarkably, a constant kPAR value of 0.06 m-1, which is indicative of optically clear open ocean conditions, is found to serve very well for OGCM prediction of SST and MLD over most of the global ocean.

Deconstructing the shallow internal structure of the Moon using GRAIL gravity and LOLA topography

NASA Astrophysics Data System (ADS)

Zuber, M. T.

2015-12-01

Globally-distributed, high-resolution gravity and topography observations of the Moon from the Gravity Recovery and Interior Laboratory (GRAIL) mission and Lunar Orbiter Laser Altimeter (LOLA) instrument aboard the Lunar Reconnaissance Orbiter (LRO) spacecraft afford the unprecedented opportunity to explore the shallow internal structure of the Moon. Gravity and topography can be combined to produce Bouguer gravity that reveals the distribution of mass in the subsurface, with high degrees in the spherical harmonic expansion of the Bouguer anomalies sensitive to shallowest structure. For isolated regions of the lunar highlands and several basins we have deconstructed the gravity field and mapped the subsurface distribution of density anomalies. While specified spherical harmonic degree ranges can be used to estimate contributions at different depths, such analyses require considerable caution in interpretation. A comparison of filtered Bouguer gravity with forward models of disk masses with plausible densities illustrates the interdependencies of the gravitational power of density anomalies with depth and spatial scale. The results have implications regarding the limits of interpretation of lunar subsurface structure.

SHUTTLE IMAGING RADAR PROVIDES FRAMEWORK FOR SUBSURFACE GEOLOGIC EXPLORATION IN EGYPT AND SUDAN.

USGS Publications Warehouse

Breed, Carol S.; McCauley, John F.; Schaber, Gerald G.

1984-01-01

Shuttle Imaging Radar provides a pictorial framework to guide exploration for mineral resources (potential placers), groundwater sources, and prehistoric archaeological sites in the Western Desert of Egypt and Sudan. Documented penetration by the SIR-A signal of dry surficial sediment to depths of a meter or more revealed bedrock geologic features and networks of former stream valleys otherwise concealed beneath windblown sand, alluvium, and colluvial deposits. 'Radar units' mapped on SIR-A images according to relative brightness and degree of mottling correspond to subsurface geologic and topographic features identified in more than 50 test pits. Petrologic examination of pit samples confirms that a variety of depositional environments existed in this now hyper-arid region before it was mantled by windblown sand sheets and dunes. Wet sand was discovered in two buried valleys shown on the radar images and located in the field with the aid of co-registered maps and Landsat images, and a satellite navigation device. Buried valleys whose streams once traversed mineralized zones are potential sites of placers (gold, tin).

Subsurface stratigraphy and oil fields in the Salem Limestone and associated rocks in Indiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, S.J.; Becker, L.E.

An area of 11 counties in southwestern Indiana was studied because (1) the subsurface geology of the Salem Limestone and associated rocks in the area contained numerous correlation discrepancies; (2) it was the locus of recent oil exploration and oil discoveries in these rocks; (3) the last subsurface study of this rock section was made in 1957; and (4) since that time, subsurface data from newly drilled petroleum-test wells have increased a hundredfold. Because of their abundance, geophysical logs were used extensively for correlation. Drill cuttings, where available, were also used in studying the rock units. The upper boundary ofmore » the Salem was based on geophysical-log correlations as supported by available drill cuttings. The lower boundary of the Salem was based on drill cuttings. Commercial oil is produced from porous calcarenite zones in the St. Louis and Salem Limestones and from coarsely crystalline limestone in the Harrodsburg Limestone. The lower part of the St. Louis Limestone yields oil from a porous carbonate rock that resembles Salem calcarenite and that we have formally named the Sission Member in the St. Louis. The Salem calcarenite facies ranges in thickness from a low of 10 percent of the total Salem in the southern part of the study area to a high of 80 percent in the northern part. Oil is produced from porous zones in the calcarenite. Oil production from the St. Louis, Salem, and Harrodsburg Limestones in Indiana amounted to 8,880,078 barrels as of December 31, 1978. Production in 1977 was 1,534,320 barrels, and production in 1978 was 1,157,450 barrels. About 80 percent of the 1977 and 1978 production came from Union-Bowman Consolidated and Sisson Fields in Gibson, Knox, and Pike counties and the Owensville North Consolidated and Mt. Carmel Consolidated Fields in Gibson County. 15 figures, 3 tables.« less

Turning Noise into Signal: Utilizing Impressed Pipeline Currents for EM Exploration

NASA Astrophysics Data System (ADS)

Lindau, Tobias; Becken, Michael

2017-04-01

Impressed Current Cathodic Protection (ICCP) systems are extensively used for the protection of central Europe's dense network of oil-, gas- and water pipelines against destruction by electrochemical corrosion. While ICCP systems usually provide protection by injecting a DC current into the pipeline, mandatory pipeline integrity surveys demand a periodical switching of the current. Consequently, the resulting time varying pipe currents induce secondary electric- and magnetic fields in the surrounding earth. While these fields are usually considered to be unwanted cultural noise in electromagnetic exploration, this work aims at utilizing the fields generated by the ICCP system for determining the electrical resistivity of the subsurface. The fundamental period of the switching cycles typically amounts to 15 seconds in Germany and thereby roughly corresponds to periods used in controlled source EM applications (CSEM). For detailed studies we chose an approximately 30km long pipeline segment near Herford, Germany as a test site. The segment is located close to the southern margin of the Lower Saxony Basin (LSB) and part of a larger gas pipeline composed of multiple segments. The current injected into the pipeline segment originates in a rectified 50Hz AC signal which is periodically switched on and off. In contrast to the usual dipole sources used in CSEM surveys, the current distribution along the pipeline is unknown and expected to be non-uniform due to coating defects that cause current to leak into the surrounding soil. However, an accurate current distribution is needed to model the fields generated by the pipeline source. We measured the magnetic fields at several locations above the pipeline and used Biot-Savarts-Law to estimate the currents decay function. The resulting frequency dependent current distribution shows a current decay away from the injection point as well as a frequency dependent phase shift which is increasing with distance from the injection point. Electric field data were recorded at 45 stations located in an area of about 60 square kilometers in the vicinity to the pipeline. Additionally, the injected source current was recorded directly at the injection point. Transfer functions between the local electric fields and the injected source current are estimated for frequencies ranging from 0.03Hz to 15Hz using robust time series processing techniques. The resulting transfer functions are inverted for a 3D conductivity model of the subsurface using an elaborate pipeline model. We interpret the model with regards to the local geologic setting, demonstrating the methods capabilities to image the subsurface.

Geophysical Summer Field Camp: Answering questions about the subsurface for the local community

NASA Astrophysics Data System (ADS)

van Wijk, K.; Batzle, M.; Liberty, L.; Raynolds, R.

2008-12-01

Summer Geophysics Field Camp is part of the core requirement for undergraduate Geophysics majors at Boise State University (CSM), as well as at Colorado School of Mines (CSM). We have found it to be most effectively taught when the target of the camp involves answering questions, which impact society. For example, currently the CSM/BSU geophysics summer camp focuses on ground water resources and geothermal potential in the Upper Arkansas River Basin, a part of the Rio Grande Rift system in Chaffee County, Colorado. A prime goal is to train students how to combine diverse sources of information into a unified interpretation: Students examine lithologies and structures on the periphery of the basin. Cross sections are constructed to predict the geophysical signature. Geophysical tools then are used to ascertain the gross structure and examine subsurface conditions in greater detail. These tools include surveying, regional gravity, deep and shallow seismic surveys, magnetics, DC resistivity, Ground Penetrating Radar, electromagnetics, hydrochemistry, and karaoke. While BSU and CSM own a considerable amount of geophysical hardware, our field camps are only possible because of extensive support by corporations and governmental agencies. In addition, the Society of Exploration Geohysics (SEG) Foundation provides financial support, Chaffee County assists with housing costs, and local land owners provide open access. In turn, the field camp results aid the community of Chaffee County in assessing their water resources for long term growth planning, as well as understanding the geothermal potential for hydroelectric power generation. BSU is currently exploring with the SEG Foundation under the Geophysicists Without Borders program to apply this model of combined education and social outreach in the form a geophysics camp for Southeast Asia, where we propose to study geohazards,geoarcheology and groundwater issues.

Near-Field Resonance Microwave Tomography and Holography

NASA Astrophysics Data System (ADS)

Gaikovich, K. P.; Smirnov, A. I.; Yanin, D. V.

2018-02-01

We develop the methods of electromagnetic computer near-field microwave tomography of distributed subsurface inhomogeneities of complex dielectric permittivity and of holography (shape retrieval) of internally homogeneous subsurface objects. The methods are based on the solution of the near-field inverse scattering problem from measurements of the resonance-parameter variations of microwave probes above the medium surface. The capabilities of the proposed diagnostic technique are demonstrated in the numerical simulation for sensors with a cylindrical capacitor as a probe element, the edge capacitance of which is sensitive to subsurface inhomogeneities.

A combined study of photospheric magnetic and current helicities and subsurface kinetic helicities of solar active regions during 2006-2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seligman, D.; Petrie, G. J. D.; Komm, R.

2014-11-10

We compare the average photospheric current helicity H{sub c} , photospheric twist parameter α (a well-known proxy for the full relative magnetic helicity), and subsurface kinetic helicity H{sub k} for 194 active regions observed between 2006-2013. We use 2440 Hinode photospheric vector magnetograms, and the corresponding subsurface fluid velocity data derived from GONG (2006-2012) and Helioseismic and Magnetic Imager (2010-2013) dopplergrams. We find a significant hemispheric bias in all three parameters. The subsurface kinetic helicity is preferentially positive in the southern hemisphere and negative in the northern hemisphere. The photospheric current helicity and the α parameter have the same biasmore » for strong fields (|B| > 1000 G) and no significant bias for weak fields (100 G <|B| < 500 G). We find no significant region-by-region correlation between the subsurface kinetic helicity and either the strong-field current helicity or α. Subsurface fluid motions of a given handedness correspond to photospheric helicities of both signs in approximately equal numbers. However, common variations appear in annual averages of these quantities over all regions. Furthermore, in a subset of 77 regions, we find significant correlations between the temporal profiles of the subsurface and photospheric helicities. In these cases, the sign of the linear correlation coefficient matches the sign relationship between the helicities, indicating that the photospheric magnetic field twist is sensitive to the twisting motions below the surface.« less

Multilayer apparent magnetization mapping approach and its application in mineral exploration

NASA Astrophysics Data System (ADS)

Guo, L.; Meng, X.; Chen, Z.

2016-12-01

Apparent magnetization mapping is a technique to estimate magnetization distribution in the subsurface from the observed magnetic data. It has been applied for geologic mapping and mineral exploration for decades. Apparent magnetization mapping usually models the magnetic layer as a collection of vertical, juxtaposed prisms in both horizontal directions, whose top and bottom surfaces are assumed to be horizontal or variable-depth, and then inverts or deconvolves the magnetic anomalies in the space or frequency domain to determine the magnetization of each prism. The conventional mapping approaches usually assume that magnetic sources contain no remanent magnetization. However, such assumptions are not always valid in mineral exploration of metallic ores. In this case, the negligence of the remanence will result in large geologic deviation or the occurrence of negative magnetization. One alternate strategy is to transform the observed magnetic anomalies into some quantities that are insensitive or weakly sensitive to the remanence and then subsequently to perform inversion on these quantities, without needing any a priori information about remanent magnetization. Such kinds of quantities include the amplitude of the magnetic total field anomaly (AMA), and the normalized magnetic source strength (NSS). Here, we present a space-domain inversion approach for multilayer magnetization mapping based on the AMA for reducing effects of remanence. In the real world, magnetization usually varies vertically in the subsurface. If we use only one-layer model for mapping, the result is simply vertical superposition of different magnetization distributions. Hence, a multi-layer model for mapping would be a more realistic approach. We test the approach on the real data from a metallic deposit area in North China. The results demonstrated that our approach is feasible and produces considerable magnetization distribution from top layer to bottom layer in the subsurface.

Improved Pseudo-section Representation for CSAMT Data in Geothermal Exploration

NASA Astrophysics Data System (ADS)

Grandis, Hendra; Sumintadireja, Prihadi

2017-04-01

Controlled-Source Audio-frequency Magnetotellurics (CSAMT) is a frequency domain sounding technique employing typically a grounded electric dipole as the primary electromagnetic (EM) source to infer the subsurface resistivity distribution. The use of an artificial source provides coherent signals with higher signal-to-noise ratio and overcomes the problems with randomness and fluctuation of the natural EM fields used in MT. However, being an extension of MT, the CSAMT data still uses apparent resistivity and phase for data representation. The finite transmitter-receiver distance in CSAMT leads to a somewhat “distorted” response of the subsurface compared to MT data. We propose a simple technique to present CSAMT data as an apparent resistivity pseudo-section with more meaningful information for qualitative interpretation. Tests with synthetic and field CSAMT data showed that the simple technique is valid only for sounding curves exhibiting a transition from high - low - high resistivity (i.e. H-type) prevailing in data from a geothermal prospect. For quantitative interpretation, we recommend the use of the full-solution of CSAMT modelling since our technique is not valid for more general cases.

How to Access and Sample the Deep Subsurface of Mars

NASA Technical Reports Server (NTRS)

Briggs, G.; Blacic, J.; Dreesen, D.; Mockler, T.

2000-01-01

We are developing a technology roadmap to support a series of Mars lander missions aimed at successively deeper and more comprehensive explorations of the Martian subsurface. The proposed mission sequence is outlined. Key to this approach is development of a drilling and sampling technology robust and flexible enough to successfully penetrate the presently unknown subsurface geology and structure. Martian environmental conditions, mission constraints of power and mass and a requirement for a high degree of automation all limit applicability of many proven terrestrial drilling technologies. Planetary protection and bioscience objectives further complicate selection of candidate systems. Nevertheless, recent advances in drilling technologies for the oil & gas, mining, underground utility and other specialty drilling industries convinces us that it will be possible to meet science and operational objectives of Mars subsurface exploration.

A method for subsurface-banding poultry litter in plots not accessible with conventional field equipment

USDA-ARS?s Scientific Manuscript database

Subsurface band application of poultry litter has been shown to be effective in reducing nutrients in runoff and leachate, relative to surface broadcast application of litter. Some field plot arrangements, such as plots having adjacent pits in the soil, prevent the use of conventional field equipme...

Active Region Formation and Subsurface Structure

NASA Astrophysics Data System (ADS)

Stein, F.; Nordlund, Robert A.

2016-10-01

We present results from emerging magnetic flux simulations showing how several different active regions form and their very different subsurface structures. The simulations assumed an infinite sheet of uniform, untwisted, horizontal field advected into the computational domain by inflows at a depth of 20 Mm. Results from two different horizontal field strengths, 1 and 5 kG, will be presented. Convective up and down flows buckle the horizontal field into Omega and U loops. Upflows and magnetic buoyancy carry the field toward the surface, while fast downflows pin down the field. Small (granular) convective motions, near the surface, shred the emerging field into fine filaments that emerge as the observed "pepper and salt" pattern. The large (supergranular) motions, at depth, keep the overall loop structure intact, so that as the overall omega-loop emerges through the surface the opposite polarity fields counter-stream into large unipolar flux concentrations producing first pores which then coalesce into spots. These tend to be located over the supergranular downflow lanes near the bottom of the domain. The pores and spots exhibit a great variety of subsurface field structures - from monolithic but twisted bundles to intertwined separate spaghetti sturctures. We will show movies of the surface evolution of the field and emergent continuum intensity and of the subsurface evolution of the magnetic field lines.

Searching for Life in the Martian Subsurface: Results from the MARTE Astrobiological Drilling Experiment and Implications for Future Missions

NASA Astrophysics Data System (ADS)

Stoker, C. R.

2007-07-01

Drilling for subsurface life should be a goal of future Mars missions. The approach is illustrated by MARTE: A search for subsurface life in Rio Tinto, Spain explored a biosphere using reduced iron and sulfur minerals and demonstrated automated drilling, sample handling, and life detection.

Subsurface examination of a foliar biofilm using scanning electron- and focused-ion-beam microscopy

USDA-ARS?s Scientific Manuscript database

The dual beam scanning electron microscope, equipped with both a focused ion- and scanning electron- beam (FIB SEM) is a novel tool for the exploration of the subsurface structure of biological tissues. The FIB is capable of removing small cross sections to view the subsurface features and may be s...

DESIGN OF A SURFACTANT REMEDIATION FIELD DEMONSTRATION BASED ON LABORATORY AND MODELINE STUDIES

EPA Science Inventory

Surfactant-enhanced subsurface remediation is being evaluated as an innovative technology for expediting ground-water remediation. This paper reports on laboratory and modeling studies conducted in preparation for a pilot-scale field test of surfactant-enhanced subsurface remedia...

Subsurface Pressure-Temperature Conditions and H2(aq) Generation at the Piccard Hydro-Thermal Field, Mid-Cayman Rise

NASA Astrophysics Data System (ADS)

Scheuermann, P. P.; Seyfried, W. E.

2018-05-01

The subsurface pressure-temperature conditions at the Piccard hydrothermal field are constrained using the Si-Cl geothermobarometer. Ol-Mgt and Opx-Mgt are proposed as assemblages that buffer H2(aq) at Piccard.

Interpretation of 2D Resistivity with Engineering Characterisation of Subsurface Exploration in Nusajaya Johor, Malaysia

NASA Astrophysics Data System (ADS)

Akip Tan, S. N. Mohd; Dan, M. F. Md; Edy Tonnizam, M.; Saad, R.; Madun, A.; Hazreek, Z. A. M.

2018-04-01

2-D resistivity technique and pole-dipole array with spacing of 2 m electrode and total spacing of 80 m were adopted to map and characterize the shallow subsurface in a sedimentary area at Nusajaya, Johor. Geological field mapping and laboratory testing were conducted to determine weathering grades. Res2Dinv software was used to generate the inversion model resistivity. The result shows sandstone contains iron mineral (30-1000ohm-m) and weathered sandstone (500-1000 ohm-m). The lowest layer represents sandstone and siltstone with the highest range from 1500 through 5000 ohm-m. The weathering grade IV and V of sandstone in the actual profile indicates the range from 30 to 1000 ohm-m, whereas grade II and III in ground mass matched the higest range. Overall, the increase of weathering grade influenced both the physical properties and strength of rocks.

Global Nonlinear Optimization for the Interpretation of Magnetic Anomalies Over Idealized Geological Bodies for Ore Exploration - An Insight about Uncertainty

NASA Astrophysics Data System (ADS)

Biswas, A.

2016-12-01

A Very Fast Simulated Annealing (VFSA) global optimization code is produced for elucidation of magnetic data over various idealized bodies for mineral investigation. The way of uncertainty in the interpretation is additionally analyzed in the present study. This strategy fits the watched information exceptionally well by some straightforward geometrically body in the confined class of Sphere, horizontal cylinder, thin dyke and sheet type models. The consequences of VFSA improvement uncover that different parameters demonstrate various identical arrangements when state of the objective body is not known and shape factor "q" is additionally advanced together with other model parameters. The study uncovers that amplitude coefficient k is firmly subject to shape factor. This demonstrates there is multi-model sort vulnerability between these two model parameters. Be that as it may, the assessed estimations of shape factor from different VFSA runs without a doubt show whether the subsurface structure is sphere, horizontal cylinder, and dyke or sheet type structure. Thus, the precise shape element (2.5 for sphere, 2.0 for horizontal cylinder and 1.0 for dyke and sheet) is settled and improvement procedure is rehashed. Next, altering the shape factor and investigation of uncertainty as well as scatter-plots demonstrates a very much characterized uni-model characteristics. The mean model figured in the wake of settling the shape factor gives the highest dependable results. Inversion of noise-free and noisy synthetic data information and additionally field information shows the adequacy of the methodology. The procedure has been carefully and practically connected to five genuine field cases with the nearness of mineralized bodies covered at various profundities in the subsurface and complex geological settings. The method can be to a great degree appropriate for mineral investigation, where the attractive information is seen because of mineral body established in the shallow/deeper subsurface and the calculation time for the entire procedure are short. Keywords: Magnetic anomaly, idealized body, uncertainty, VFSA, multiple structure, ore exploration.

Searching for Life Underground: An Analysis of Remote Sensing Observations of a Drill Core from Rio Tinto, Spain for Mineralogical Indications of Biological Activity

NASA Technical Reports Server (NTRS)

Battler, M.; Stoker, C.

2005-01-01

Water is unstable on the surface of Mars, and therefore the Martian surface is not likely to support life. It is possible, however, that liquid water exists beneath the surface of Mars, and thus life might also be found in the subsurface. Subsurface life would most likely be microbial, anaerobic, and chemoautotrophic; these types of biospheres on Earth are rare, and not well understood. Finding water and life are high priorities for Mars exploration, and therefore it is important that we learn to explore the subsurface robotically, by drilling. The Mars Analog Rio Tinto Experiment (MARTE), has searched successfully for a subsurface biosphere at Rio Tinto, Spain [1,2,3,4]. The Rio Tinto study site was selected to search for a subsurface biosphere because the extremely low pH and high concentrations of elements such as iron and copper in the Tinto River suggest the presence of a chemoautotrophic biosphere in the subsurface beneath the river. The Rio Tinto has been recognized as an important mineralogical analog to the Sinus Meridiani site on Mars [5].

Habitat Inspection Scanner, Bio-Structure Scanner, and In Situ Sub-Surface Composition Sensor

NASA Technical Reports Server (NTRS)

VanSteenberg, Michael

2004-01-01

The extension of dielectric and inductive spectroscopy into in situ observations represents a significant exploration-enabling tool. This technology can be widely applied from microscopic to macroscopic. Dielectrometry and inductometry can measure sub-surface composition and its distribution. The primary environment that we cannot easily explored is the sub-surface of solid bodies. Weather as part of our equipment that we bring with us, or the locations we are exploring. These fundamental questions lie at the core of the exploration Initiative. To answer them we must use a whole host of complimentary tools including those that allow us to practically examine the sub-surface environment. A nondestructive approach offers significant advantages for both the initial identification of likely samples but also the monitoring of ecosystems and crew health. These include materials characterization, nondestructive inspection, and process quality control, damage monitoring, and hidden object detection and identification. The identification of natural resources such as water on the Moon or Mars is of great importance to the utilization of local resource in the support of human exploration crews. On the macroscopic scale, the understanding of what resources are available and how they are distributed is of primary importance to their productive utilization. Even if initial explorations do not require the use of local resources to succeed, eventual settlement and commercial development will. The routine examination of the structural integrity (micro cracks, leaks) of hi.inafi habitats in harsh envkmments ww!d also be enabled.

The Effect of Projectile Density and Disruption on the Crater Excavation Flow-Field

NASA Technical Reports Server (NTRS)

Anderson, Jennifer L. B.; Schultz, P. H.

2005-01-01

The ejection parameters of material excavated by a growing crater directly relate to the subsurface excavation flow-field. The ejection angles and speeds define the end of subsurface material streamlines at the target surface. Differences in the subsurface flow-fields can be inferred by comparing observed ejection parameters of various impacts obtained using three-dimensional particle image velocimetry (3D PIV). The work presented here investigates the observed ejection speeds and angles of material ejected during vertical (90 impact angle) experimental impacts for a range of different projectile types. The subsurface flow-fields produced during vertical impacts are simple when compared with that of oblique impacts, affected primarily by the depth of the energy and momentum deposition of the projectile. This depth is highly controlled by the projectile/target density ratio and the disruption of the projectile (brittle vs. ductile deformation). Previous studies indicated that cratering efficiency and the crater diameter/depth ratio were affected by projectile disruption, velocity, and the projectile/target density ratio. The effect of these projectile properties on the excavation flow-field are examined by comparing different projectile materials.

Using Analog Field Tests To Link and Prepare Science and In-Situ Resource Utilization for Future Space Missions

NASA Technical Reports Server (NTRS)

Sanders, Gerald B.

2010-01-01

A major goal of NASA s human exploration program is to learn how to use the resources of space, known as In-Situ Resource Utilization (ISRU), to lower the cost and risk of human space exploration. Successful implementation of ISRU requires detailed knowledge of surface and subsurface materials, minerals, and volatiles that may be present. This same information is required to better understand the physical and geologic composition, structure, origin, and evolution of the Moon, Mars, and other extraterrestrial bodies of interest. It is also important to recognize that while ISRU and science objectives may be similar, the desired method or hardware to achieve the information desired may be drastically different. One method to promote understanding, coordination, and joint development of instruments and operations between Science and ISRU is the use of analog field demonstrations.

Modular evaluation method for subsurface activities (MEMSA). A novel approach for integrating social acceptance in a permit decision-making process for subsurface activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Os, Herman W.A. van, E-mail: h.w.a.van.os@rug.nl; Herber, Rien, E-mail: rien.herber@rug.nl; Scholtens, Bert, E-mail: l.j.r.scholtens@rug.nl

We investigate how the decision support system ‘Modular Evaluation Method Subsurface Activities’ (MEMSA) can help facilitate an informed decision-making process for permit applications of subsurface activities. To this end, we analyze the extent the MEMSA approach allows for a dialogue between stakeholders in a transparent manner. We use the exploration permit for the underground gas storage facility at the Pieterburen salt dome (Netherlands) as a case study. The results suggest that the MEMSA approach is flexible enough to adjust to changing conditions. Furthermore, MEMSA provides a novel way for identifying structural problems and possible solutions in permit decision-making processes formore » subsurface activities, on the basis of the sensitivity analysis of intermediate rankings. We suggest that the planned size of an activity should already be specified in the exploration phase, because this would allow for a more efficient use of the subsurface as a whole. We conclude that the host community should be involved to a greater extent and in an early phase of the permit decision-making process, for example, already during the initial analysis of the project area of a subsurface activity. We suggest that strategic national policy goals are to be re-evaluated on a regular basis, in the form of a strategic vision for the subsurface, to account for timing discrepancies between the realization of activities and policy deadlines, because this discrepancy can have a large impact on the necessity and therefore acceptance of a subsurface activity.« less

Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming.

PubMed

Huang, Ping; Lin, I-I; Chou, Chia; Huang, Rong-Hui

2015-05-18

Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming

PubMed Central

Huang, Ping; Lin, I. -I; Chou, Chia; Huang, Rong-Hui

2015-01-01

Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas. PMID:25982028

Debates - Stochastic subsurface hydrology from theory to practice: Introduction

NASA Astrophysics Data System (ADS)

Rajaram, Harihar

2016-12-01

This paper introduces the papers in the "Debates - Stochastic Subsurface Hydrology from Theory to Practice" series. Beginning in the 1970s, the field of stochastic subsurface hydrology has been an active field of research, with over 3500 journal publications, of which over 850 have appeared in Water Resources Research. We are fortunate to have insightful contributions from four groups of distinguished authors who discuss the reasons why the advanced research framework established in stochastic subsurface hydrology has not impacted the practice of groundwater flow and transport modeling and design significantly. There is reasonable consensus that a community effort aimed at developing "toolboxes" for applications of stochastic methods will make them more accessible and encourage practical applications.

Microbial physiology-based model of ethanol metabolism in subsurface sediments

NASA Astrophysics Data System (ADS)

Jin, Qusheng; Roden, Eric E.

2011-07-01

A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

Structure and function of subsurface microbial communities affecting radionuclide transport and bioimmobilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostka, Joel E.; Prakash, Om; Green, Stefan J.

2012-05-01

Our objectives were to: 1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), 2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and 3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations. Field sampling was conducted at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee. Themore » ORFRC subsurface is exposed to mixed contamination predominated by uranium and nitrate. In short, we effectively addressed all 3 stated objectives of the project. In particular, we isolated and characterized a large number of novel anaerobes with a high bioremediation potential that can be used as model organisms, and we are now able to quantify the function of subsurface sedimentary microbial communities in situ using state-of-the-art gene expression methods (molecular proxies).« less

Geophysical exploration on the subsurface geology of La Garrotxa monogenetic volcanic field (NE Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Bolós, Xavier; Barde-Cabusson, Stéphanie; Pedrazzi, Dario; Martí, Joan; Casas, Albert; Lovera, Raúl; Nadal-Sala, Daniel

2014-11-01

We applied self-potential (SP) and electrical resistivity tomography (ERT) to the exploration of the uppermost part of the substrate geology and shallow structure of La Garrotxa monogenetic volcanic field, part of the European Neogene-Quaternary volcanic province. The aim of the study was to improve knowledge of the shallowest part of the feeding system of these monogenetic volcanoes and of its relationship with the subsurface geology. This study complements previous geophysical studies carried out at a less detailed scale and aimed at identifying deeper structures, and together will constitute the basis to establish volcanic susceptibility in La Garrotxa. SP study complemented previous smaller-scale studies and targeted key areas where ERT could be conducted. The main new results include the generation of resistivity models identifying dykes and faults associated with several monogenetic cones. The combined results confirm that shallow tectonics controlling the distribution of the foci of eruptive activity in this volcanic zone mainly correspond to NNW-SSE and accessorily by NNE-SSW Neogene extensional fissures and faults and concretely show the associated magmatic intrusions. These structures coincide with the deeper ones identified in previous studies, and show that previous Alpine tectonic structures played no apparent role in controlling the loci of this volcanism. Moreover, the results obtained show that the changes in eruption dynamics occurring at different vents located at relatively short distances in this volcanic area are controlled by shallow stratigraphical, structural and hydrogeological differences underneath these monogenetic volcanoes.

Microbial Life in the Deep Subsurface: Deep, Hot and Radioactive

NASA Technical Reports Server (NTRS)

DeStefano, Andrea L.; Ford, Jill C.; Winsor, Seana K.; Allen, Carlton C.; Miller, Judith; McNamara, Karen M.; Gibson, Everett K., Jr.

2000-01-01

Recent studies, motivated in part by the search for extraterrestrial life, continue to expand the recognized limits of Earth's biosphere. This work explored evidence for life a high-temperature, radioactive environment in the deep subsurface.

Method and apparatus for subsurface exploration

NASA Technical Reports Server (NTRS)

Wilcox, Brian (Inventor)

2002-01-01

A subsurface explorer (SSX) for exploring beneath the terrestrial surface of planetary bodies such as the Earth, Mars, or comets. This exploration activity utilizes appropriate sensors and instrument to evaluate the composition, structure, mineralogy and possibly biology of the subsurface medium, as well as perhaps the ability to return samples of that medium back to the surface. The vehicle comprises an elongated skin or body having a front end and a rear end, with a nose piece at the front end for imparting force to composition material of the planetary body. Force is provided by a hammer mechanism to the back side of a nose piece from within the body of the vehicle. In the preferred embodiment, a motor spins an intermediate shaft having two non-uniform threads along with a hammer which engages these threads with two conical rollers. A brake assembly halts the rotation of the intermediate shaft, causing the conical roller to spin down the non-uniform thread to rapidly and efficiently convert the rotational kinetic energy of the hammer into translational energy.

Complete genome sequence of Anaeromyxobacter sp. Fw109-5, an Anaerobic, Metal-Reducing Bacterium Isolated from a Contaminated Subsurface Environment

DOE PAGES

Hwang, C.; Copeland, A.; Lucas, Susan; ...

2015-01-22

We report the genome sequence of Anaeromyxobacter sp. Fw109-5, isolated from nitrate- and uranium-contaminated subsurface sediment of the Oak Ridge Integrated Field-Scale Subsurface Research Challenge (IFC) site, Oak Ridge Reservation, TN. The bacterium’s genome sequence will elucidate its physiological potential in subsurface sediments undergoing in situ uranium bioremediation and natural attenuation.

Extraction of remanent magnetization from magnetization vector inversions of airborne full tensor magnetic gradiometry data

NASA Astrophysics Data System (ADS)

Queitsch, M.; Schiffler, M.; Stolz, R.; Meyer, M.; Kukowski, N.

2017-12-01

Measurements of the Earth's magnetic field are one of the most used methods in geophysical exploration. The ambiguity of the method, especially during modeling and inversion of magnetic field data sets, is one of its biggest challenges. Additional directional information, e.g. gathered by gradiometer systems based on Superconducting Quantum Interference Devices (SQUIDs), will positively influence the inversion results and will thus lead to better subsurface magnetization models. This is especially beneficial, regarding the shape and direction of magnetized structures, especially when a significant remanent magnetization of the underlying sources is present. The possibility to separate induced and remanent contributions to the total magnetization may in future also open up advanced ways for geological interpretation of the data, e.g. a first estimation of diagenesis processes. In this study we present the results of airborne full tensor magnetic gradiometry (FTMG) surveys conducted over a dolerite intrusion in central Germany and the results of two magnetization vector inversions (MVI) of the FTMG and a conventional total field anomaly data set. A separation of the two main contributions of the acquired total magnetization will be compared with information of the rock magnetization measured on orientated rock samples. The FTMG inversion results show a much better agreement in direction and strength of both total and remanent magnetization compared to the inversion using only total field anomaly data. To enhance the separation process, the application of additional geophysical methods, i.e. frequency domain electromagnetics (FDEM), in order to gather spatial information of subsurface rock susceptibility will also be discussed. In this approach, we try to extract not only information on subsurface conductivity but also the induced magnetization. Using the total magnetization from the FTMG data and the induced magnetization from the FDEM data, the full separation of induced and remanent magnetization should be enabled. First results this approach will be shown and discussed.

Nutrient loss in leachate and surface runoff from surface-broadcast and subsurface-banded broiler litter

USDA-ARS?s Scientific Manuscript database

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff, compared to the conventional surface broadcast application. Little in situ research has been conducted to determine effects of surface broadcast application and subsurfac...

The Hebrus Valles Exploration Zone: Access to the Martian Surface and Subsurface

NASA Astrophysics Data System (ADS)

Davila, A.; Fairén, A. G.; Rodríguez, A. P.; Schulze-Makuch, D.; Rask, J.; Zavaleta, J.

2015-10-01

The Hebrus Valles EZ represents a diverse setting with multiple geological contacts and layers, possible remnant water ice and protected subsurface environments, which could be critical for the establishment of long-term human settlements.

The Naiades: A Mars Scout Proposal for Electromagnetic and Seismic Exploration for Groundwater on Mars

NASA Astrophysics Data System (ADS)

Grimm, R. E.

2002-09-01

Detection of subsurface, liquid water is an overarching objective of the Mars Exploration Program (MEP) because of its impacts on life, climate, geology, and preparation for human exploration. Although planned orbital radars seek to map subsurface water, methods with more robust depth-penetration, discrimination, and characterization capabilities are necessary to "ground truth" any results from such radars. Low-frequency electromagnetic (EM) methods exploit induction rather than wave propagation and are sensitive to electrical conductivity rather than dielectric constant. Saline martian groundwater will be a near-ideal EM target, especially as the overburden is likely very dry. The Naiades Mars Scout - named for the Greek mythological nymphs of springs, rivers, lakes, and fountains - comprise twin Landers directed to a high-priority region for groundwater investigation. Broadband measurements of natural EM fields will be used to perform passive soundings. If natural sources are weak, active soundings will be performed using a small transmitter. The two Landers are positioned within several tens of kilometers of each other so that coherence techniques can improve data quality; useful data can, however, be acquired by a single Lander. Additional mission objectives include detection of ground ice, characterization of natural EM fields, measurement of electrical properties, constraints on planetary heat flow, measurement of crustal magnetism, characterization of seismicity, seismic imaging of the interior, and assessment of landing-site geomorphology. A short-period seismometer and a wide-angle camera complete the payload to achieve these objectives. The Naiades mission strongly resonates with the main "Follow the Water" theme of the MEP, but in ways that are not currently within the its scope or that of international partners. The combination of established terrestrial methods for groundwater exploration, robust flight systems, and cost effectiveness proposed for the Naiades is a relatively low-risk approach to answering key questions about water on Mars within the Scout framework

A Microbial Oasis in the Hypersaline Atacama Subsurface Discovered by a Life Detector Chip: Implications for the Search for Life on Mars

PubMed Central

de Diego-Castilla, Graciela; Moreno-Paz, Mercedes; Blanco, Yolanda; Cruz-Gil, Patricia; Rodríguez-Manfredi, José A.; Fernández-Remolar, David; Gómez, Felipe; Gómez, Manuel J.; Rivas, Luis A.; Demergasso, Cecilia; Echeverría, Alex; Urtuvia, Viviana N.; Ruiz-Bermejo, Marta; García-Villadangos, Miriam; Postigo, Marina; Sánchez-Román, Mónica; Chong-Díaz, Guillermo; Gómez-Elvira, Javier

2011-01-01

Abstract The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5 m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2 m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5 g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260 g kg−1) and perchlorate (41.13 μg g−1 maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14 μg g−1) or formate (76.06 μg g−1) as electron donors, and sulfate (15875 μg g−1), nitrate (13490 μg g−1), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars. Key Words: Atacama Desert—Life detection—Biosensor—Biopolymers—In situ measurement. Astrobiology 11, 969–996. PMID:22149750

A microbial oasis in the hypersaline Atacama subsurface discovered by a life detector chip: implications for the search for life on Mars.

PubMed

Parro, Victor; de Diego-Castilla, Graciela; Moreno-Paz, Mercedes; Blanco, Yolanda; Cruz-Gil, Patricia; Rodríguez-Manfredi, José A; Fernández-Remolar, David; Gómez, Felipe; Gómez, Manuel J; Rivas, Luis A; Demergasso, Cecilia; Echeverría, Alex; Urtuvia, Viviana N; Ruiz-Bermejo, Marta; García-Villadangos, Miriam; Postigo, Marina; Sánchez-Román, Mónica; Chong-Díaz, Guillermo; Gómez-Elvira, Javier

2011-12-01

The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5 m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2 m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5 g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260 g kg(-1)) and perchlorate (41.13 μg g(-1) maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14 μg g(-1)) or formate (76.06 μg g(-1)) as electron donors, and sulfate (15875 μg g(-1)), nitrate (13490 μg g(-1)), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars.

Robotic Range Clearance Competition (R2C2)

DTIC Science & Technology

2011-10-01

unexploded ordnance (UXO). A large part of the debris field consists of ferrous metal objects that magnetic 39 Distribution A: Approved for public...was set at 7 degrees above horizontal based on terrain around the Base station. We used the BSUBR file for all fields except the Subsurface...and subsurface clearance test areas had numerous pieces of simulated unexploded ordinance (SUXO) buried at random locations around the field . These

Reduction of the 355-nm laser-induced damage initiators by removing the subsurface cracks in fused silica

NASA Astrophysics Data System (ADS)

Yang, Minghong; Qi, Hongji; Zhao, Yuanan; Yi, Kui

2012-01-01

The 355 nm laser-induced damage thresholds (LIDTs) of polished fused silica with and without the residual subsurface cracks were explored. HF based wet etching and magnetorheological finishing was used to remove the subsurface cracks. To isolate the effect of subsurface cracks, chemical leaching was used to eliminate the photoactive impurities in the polishing layer. Results show that the crack number density decreased from~103 to <1cm-2, and the LIDT was improved as high as 2.8-fold with both the subsurface cracks and the polishing layer being removed. Subsurface cracks play a significant role in laser damage at fluencies between 15~31 J/cm2 (355nm, 8ns). HF Etching of the cracks was shown to increase the damage performance as nearly high as that of the samples in which subsurface cracks are well controlled.

Proceedings of Tunnel Detection Symposium on Subsurface Exploration Technology (4th) held in Golden, Colorado on 26 - 29 Apr 1993

DTIC Science & Technology

1993-04-29

characteristics such as intuition, telepathy , ESP, PSI, subconscious creativity and the likz. "Don’t do it Ruskey," they told me, "give them nuts and bolts." Nuts...basic shape of the homogeneous media response ( i.e. the primary wave). The synthetic waveforms 72 show good conformance with the field data. The minor...as a fracture halo surrounding the tunnel which is unaccounted for in the simulation. Figure 5 shows a suite of synthetic waveforms for an air tilled

Reflection seismic imaging in the volcanic area of the geothermal field Wayang Windu, Indonesia

NASA Astrophysics Data System (ADS)

Polom, Ulrich; Wiyono, Wiyono; Pramono, Bambang; Krawczyk, CharLotte M.

2014-05-01

Reflection seismic exploration in volcanic areas is still a scientific challenge and requires major efforts to develop imaging workflows capable of an economic utilization, e.g., for geothermal exploration. The SESaR (Seismic Exploration and Safety Risk study for decentral geothermal plants in Indonesia) project therefore tackles still not well resolved issues concerning wave propagation or energy absorption in areas covered by pyroclastic sediments using both active P-wave and S-wave seismics. Site-specific exploration procedures were tested in different tectonic and lithological regimes to compare imaging conditions. Based on the results of a small-scale, active seismic pre-site survey in the area of the Wayang Windu geothermal field in November 2012, an additional medium-scale active seismic experiment using P-waves was carried out in August 2013. The latter experiment was designed to investigate local changes of seismic subsurface response, to expand the knowledge about capabilities of the vibroseis method for seismic surveying in regions covered by pyroclastic material, and to achieve higher depth penetration. Thus, for the first time in the Wayang Windu geothermal area, a powerful, hydraulically driven seismic mini-vibrator device of 27 kN peak force (LIAG's mini-vibrator MHV2.7) was used as seismic source instead of the weaker hammer blow applied in former field surveys. Aiming at acquiring parameter test and production data southeast of the Wayang Windu geothermal power plant, a 48-channel GEODE recording instrument of the Badan Geologi was used in a high-resolution configuration, with receiver group intervals of 5 m and source intervals of 10 m. Thereby, the LIAG field crew, Star Energy, GFZ Potsdam, and ITB Bandung acquired a nearly 600 m long profile. In general, we observe the successful applicability of the vibroseis method for such a difficult seismic acquisition environment. Taking into account the local conditions at Wayang Windu, the method is superior to the common seismic explosive source techniques, both with respect to production rate as well as resolution and data quality. Source signal frequencies of 20-80 Hz are most efficient for the attempted depth penetration, even though influenced by the dry subsurface conditions during the experiment. Depth penetration ranges between 0.5-1 km. Based on these new experimental data, processing workflows can be tested the first time for adapted imaging strategies. This will not only allow to focus on larger exploration depths covering the geothermal reservoir at the Wayang Windu power plant site itself, but also opens the possibility to transfer the lessons learned to other sites.

Results from Field Testing the RIMFAX GPR on Svalbard.

NASA Astrophysics Data System (ADS)

Hamran, S. E.; Amundsen, H. E. F.; Berger, T.; Carter, L. M.; Dypvik, H.; Ghent, R. R.; Kohler, J.; Mellon, M. T.; Nunes, D. C.; Paige, D. A.; Plettemeier, D.; Russell, P.

2017-12-01

The Radar Imager for Mars' Subsurface Experiment - RIMFAX is a Ground Penetrating Radar being developed for NASÁs MARS 2020 rover mission. The principal goals of the RIMFAX investigation are to image subsurface structures, provide context for sample sites, derive information regarding subsurface composition, and search for ice or brines. In meeting these goals, RIMFAX will provide a view of the stratigraphic section and a window into the geological and environmental history of Mars. To verify the design an Engineering Model (EM) of the radar was tested in the field in the spring 2017. Different sounding modes on the EM were tested in different types of subsurface geology on Svalbard. Deep soundings were performed on polythermal glaciers down to a couple of hundred meters. Shallow soundings were used to map a ground water table in the firn area of a glacier. A combination of deep and shallow soundings was used to image buried ice under a sedimentary layer of a couple of meters. Subsurface sedimentary layers were imaged down to more than 20 meters in sand stone permafrost. This presentation will give an overview of the RIMFAX investigation, describe the development of the radar system, and show results from field tests of the radar.

Application of ground-penetrating radar methods in determining hydrogeologic conditions in a karst area, west-central Florida

USGS Publications Warehouse

Barr, G.L.

1993-01-01

Ground-penetrating radar (GPR) is useful as a surface geophysical method for exploring geology and subsurface features in karst settings. Interpretation of GPR data was used to infer lithology and hydrogeologic conditions in west-central Florida. This study demonstrates how GPR methods can be used to investigate the hydrogeology of an area. GPR transmits radio- frequency electromagnetic waves into the ground and receives reflected energy waves from subsurface interfaces. Subsurface profiles showing sediment thickness, depth to water table and clay beds, karst development, buried objects, and lake-bottom structure were produced from GPR traverses obtained during December 1987 and March 1990 in Pinellas, Hillsborough, and Hardee Counties in west-central Florida. Performance of the GPR method is site specific, and data collected are principally affected by the sediment and pore fluids, conductances and dielectric constants. Effective exploration depths of the GPR surveys through predominately unsaturated and saturated sand and clay sediments at five study sites ranged from a few feet to greater than 50 feet below land surface. Exploration depths were limited when high conductivity clay was encountered, whereas greater exploration depths were possible in material composed of sand. Application of GPR is useful in profiling subsurface conditions, but proper interpretation depends upon the user's knowledge of the equipment and the local hydrogeological setting, as well as the ability to interpret the graphic profile.

Probing the critical zone using passive- and active-source estimates of subsurface shear-wave velocities

NASA Astrophysics Data System (ADS)

Callahan, R. P.; Taylor, N. J.; Pasquet, S.; Dueker, K. G.; Riebe, C. S.; Holbrook, W. S.

2016-12-01

Geophysical imaging is rapidly becoming popular for quantifying subsurface critical zone (CZ) architecture. However, a diverse array of measurements and measurement techniques are available, raising the question of which are appropriate for specific study goals. Here we compare two techniques for measuring S-wave velocities (Vs) in the near surface. The first approach quantifies Vs in three dimensions using a passive source and an iterative residual least-squares tomographic inversion. The second approach uses a more traditional active-source seismic survey to quantify Vs in two dimensions via a Monte Carlo surface-wave dispersion inversion. Our analysis focuses on three 0.01 km2 study plots on weathered granitic bedrock in the Southern Sierra Critical Zone Observatory. Preliminary results indicate that depth-averaged velocities from the two methods agree over the scales of resolution of the techniques. While the passive- and active-source techniques both quantify Vs, each method has distinct advantages and disadvantages during data acquisition and analysis. The passive-source method has the advantage of generating a three dimensional distribution of subsurface Vs structure across a broad area. Because this method relies on the ambient seismic field as a source, which varies unpredictably across space and time, data quality and depth of investigation are outside the control of the user. Meanwhile, traditional active-source surveys can be designed around a desired depth of investigation. However, they only generate a two dimensional image of Vs structure. Whereas traditional active-source surveys can be inverted quickly on a personal computer in the field, passive source surveys require significantly more computations, and are best conducted in a high-performance computing environment. We use data from our study sites to compare these methods across different scales and to explore how these methods can be used to better understand subsurface CZ architecture.

[Influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield.

PubMed

Zhang, Ming Zhi; Niu, Wen Quan; Xu, Jian; Li, Yuan

2016-06-01

In order to explore the influences of micro-irrigation and subsoiling before planting on enzyme activity in soil rhizosphere and summer maize yield, an orthogonal experiment was carried out with three factors of micro-irrigation method, irrigation depth, and subsoiling depth. The factor of irrigation method included surface drip irrigation, subsurface drip irrigation, and moistube-irrigation; three levels of irrigation depth were obtained by controlling the lower limit of soil water content to 50%, 65%, and 80% of field holding capacity, respectively; and three depths of deep subsoiling were 20, 40, and 60 cm. The results showed that the activities of catalase and urease increased first and then decreased, while the activity of phosphatase followed an opposite trend in the growth season of summer maize. Compared with surface drip irrigation and moistube-irrigation, subsurface drip irrigation increased the average soil moisture of 0-80 cm layer by 6.3% and 1.8% in the growth season, respectively. Subsurface drip irrigation could significantly increase soil urease activity, roots volume, and yield of summer maize. With the increase of irrigation level, soil phosphatase activity decreased first and then increased, while urease activity and yield increased first and then decreased. The average soil moisture and root volume all increased in the growth season of summer maize. The increments of yield and root volume from subsoiling of 40 to 20 cm were greater than those from 60 to 40 cm. The highest enzyme activity was obtained with the treatment of subsoiling of 40 cm. In terms of improving water resource use efficiency, nitrogen use efficiency, and crop yield, the best management strategy of summer maize was the combination of subsurface drip irrigation, controlling the lower limit of soil water content to 65% of field holding capacity, and 40 cm subsoiling before planting.

Desert Studies - A Global View

DTIC Science & Technology

1985-08-23

Exploration, Dec. 6-10, 1982, Ft. Worth, TX, p. 39-40. 1983: 2 abs. published, 2 papers submitted for publication Breed, C. S., 1983, Subsurface imaging with...2-10 (in Chinese). Elachi, C., Roth, L. E., and Schaber, G. G., 1984, Spaceborne radar subsurface imaging in hyperarid regions, 1984: IEEE...are 55) km o. 18t BIBLIOGRAPHY (CITED REFERENCES) Breed, C. S., 1983, Subsurface imaging with SIR-A in the Egyptian Desert (abs.): Summaries, 17th

The emergence of hydrogeophysics for improved understanding of subsurface processes over multiple scales

DOE PAGES

Binley, Andrew; Hubbard, Susan S.; Huisman, Johan A.; ...

2015-06-15

Geophysics provides a multidimensional suite of investigative methods that are transforming our ability to see into the very fabric of the subsurface environment, and monitor the dynamics of its fluids and the biogeochemical reactions that occur within it. Here we document how geophysical methods have emerged as valuable tools for investigating shallow subsurface processes over the past two decades and offer a vision for future developments relevant to hydrology and also ecosystem science. The field of “hydrogeophysics” arose in the late 1990s, prompted, in part, by the wealth of studies on stochastic subsurface hydrology that argued for better field-based investigativemore » techniques. These new hydrogeophysical approaches benefited from the emergence of practical and robust data inversion techniques, in many cases with a view to quantify shallow subsurface heterogeneity and the associated dynamics of subsurface fluids. Furthermore, the need for quantitative characterization stimulated a wealth of new investigations into petrophysical relationships that link hydrologically relevant properties to measurable geophysical parameters. Development of time-lapse approaches provided a new suite of tools for hydrological investigation, enhanced further with the realization that some geophysical properties may be sensitive to biogeochemical transformations in the subsurface environment, thus opening up the new field of “biogeophysics.” Early hydrogeophysical studies often concentrated on relatively small “plot-scale” experiments. More recently, however, the translation to larger-scale characterization has been the focus of a number of studies. In conclusion, geophysical technologies continue to develop, driven, in part, by the increasing need to understand and quantify key processes controlling sustainable water resources and ecosystem services.« less

The emergence of hydrogeophysics for improved understanding of subsurface processes over multiple scales

DOE Office of Scientific and Technical Information (OSTI.GOV)

Binley, Andrew; Hubbard, Susan S.; Huisman, Johan A.

Geophysics provides a multidimensional suite of investigative methods that are transforming our ability to see into the very fabric of the subsurface environment, and monitor the dynamics of its fluids and the biogeochemical reactions that occur within it. Here we document how geophysical methods have emerged as valuable tools for investigating shallow subsurface processes over the past two decades and offer a vision for future developments relevant to hydrology and also ecosystem science. The field of “hydrogeophysics” arose in the late 1990s, prompted, in part, by the wealth of studies on stochastic subsurface hydrology that argued for better field-based investigativemore » techniques. These new hydrogeophysical approaches benefited from the emergence of practical and robust data inversion techniques, in many cases with a view to quantify shallow subsurface heterogeneity and the associated dynamics of subsurface fluids. Furthermore, the need for quantitative characterization stimulated a wealth of new investigations into petrophysical relationships that link hydrologically relevant properties to measurable geophysical parameters. Development of time-lapse approaches provided a new suite of tools for hydrological investigation, enhanced further with the realization that some geophysical properties may be sensitive to biogeochemical transformations in the subsurface environment, thus opening up the new field of “biogeophysics.” Early hydrogeophysical studies often concentrated on relatively small “plot-scale” experiments. More recently, however, the translation to larger-scale characterization has been the focus of a number of studies. In conclusion, geophysical technologies continue to develop, driven, in part, by the increasing need to understand and quantify key processes controlling sustainable water resources and ecosystem services.« less

Preliminary Study of 2-D Time Domain Electromagnetic (TDEM) Modeling to Analyze Subsurface Resistivity Distribution and its Application to the Geothermal Systems

NASA Astrophysics Data System (ADS)

Aji Hapsoro, Cahyo; Purqon, Acep; Srigutomo, Wahyu

2017-07-01

2-D Time Domain Electromagnetic (TDEM) has been successfully conducted to illustrate the value of Electric field distribution under the Earth surface. Electric field compared by magnetic field is used to analyze resistivity and resistivity is one of physical properties which very important to determine the reservoir potential area of geothermal systems as one of renewable energy. In this modeling we used Time Domain Electromagnetic method because it can solve EM field interaction problem with complex geometry and to analyze transient problems. TDEM methods used to model the value of electric and magnetic fields as a function of the time combined with the function of distance and depth. The result of this modeling is Electric field intensity value which is capable to describe the structure of the Earth’s subsurface. The result of this modeling can be applied to describe the Earths subsurface resistivity values to determine the reservoir potential of geothermal systems.

Geophysical framework of the southwestern Nevada volcanic field and hydrogeologic implications

USGS Publications Warehouse

Grauch, V.J.; Sawyer, David A.; Fridrich, Chris J.; Hudson, Mark R.

1999-01-01

Gravity and magnetic data, when integrated with other geophysical, geological, and rock-property data, provide a regional framework to view the subsurface geology in the southwestern Nevada volcanic field. The region has been loosely divided into six domains based on structural style and overall geophysical character. For each domain, the subsurface tectonic and magmatic features that have been inferred or interpreted from previous geophysical work has been reviewed. Where possible, abrupt changes in geophysical fields as evidence for potential structural lithologic control on ground-water flow has been noted. Inferred lithology is used to suggest associated hydrogeologic units in the subsurface. The resulting framework provides a basis for investigators to develop hypotheses from regional ground-water pathways where no drill-hole information exists.

EuroGeoMars Field Campaign: habitability studies in preparation for future Mars missions

NASA Astrophysics Data System (ADS)

Ehrenfreund, Pascale; Foing, B. H.; Stoker, C.; Zhavaleta, J.; Orzechowska, G.; Kotler, M.; Martins, Z.; Sephton, M.; Becker, L.; Quinn, R.; van Sluis, C.; Boche-Sauvan, L.; Gross, C.; Thiel, C.; Wendt, L.; Sarrazin, P.; Mahapatra, P.; Direito, S.; Roling, W.

The goal of the EuroGeoMars field campaign sponsored by ESA, NASA and the international lunar exploration working group (ILEWG) was to demonstrate instrument capabilities in sup-port of current and future planetary missions, to validate a procedure for Martian surface in-situ and return science, and to study human performance aspects. The Mars Desert Re-search Station (MDRS) represents an ideal basis to simulate aspects of robotic and human exploration in support of future missions to planetary bodies. During the campaign, MDRS Crew 77 tested X-ray diffraction and Raman instruments, and assessed habitat and operations. Special emphasis was given to sample collection in the geologically rich vicinity of MDRS and subsequent analysis of organic molecules in the soil to simulate the search for bio-signatures with field instrumentation. We describe the results of in-situ and posterior analysis of the physical and chemical properties including elemental composition, salt concentrations as well as carbon and amino acid abundances. The analyses of organics and minerals show that the subsurface mineral matrix represents a key to our understanding of the survival of organics on Mars.

Vanguard - a proposed European astrobiology experiment on Mars

NASA Astrophysics Data System (ADS)

Ellery, A. A.; Cockell, C. S.; Edwards, H. G. M.; Dickensheets, D. L.; Welch, C. S.

2002-07-01

We propose a new type of robotic mission for the exploration of Mars. This mission is called Vanguard and represents the fruits of a collaboration that is both international and multi-disciplinary. Vanguard is designed for sub-surface penetration and investigation using remote instruments and unlike previous robotic architectures it offers the opportunity for multiple subsurface site analysis using three moles. The moles increase the probability that a subsurface signature of life can be found and by accomplishing subsurface analysis across a transect, the statistical rigour of Martian scientific exploration would be improved. There is no provision for returning samples to the surface for analysis by a gas-chromatograph/mass-spectrometer (GCMS) this minimizes the complexity invoked by sophisticated robotic overheads. The primary scientific instruments to be deployed are the Raman spectrometer, infrared spectrometer and laser-induced breakdown spectroscope the Raman spectrometer in particular is discussed. We concentrate primarily on the scientific rationale for the Vanguard mission proposal. The Vanguard mission proposal represents a logical opportunity for extending European robotic missions to Mars.

Integration of Full Tensor Gravity and Z-Axis Tipper Electromagnetic Passive Low Frequency EM Instruments for Simultaneous Data Acquisition - Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wieberg, Scott

Ground gravity is a common and useful tool for geothermal exploration. Gravity surveys map density changes in the subsurface that may be caused by tectonic deformation such as faulting, fracturing, plutonism, volcanism, hydrothermal alteration, etc. Full Tensor Gravity Gradient (FTG) data has been used for over a decade in both petroleum and mining exploration to map changes in density associated with geologic structure. Measuring the gravity gradient, rather than the gravity field, provides significantly higher resolution data. Modeling studies have shown FTG data to be a viable tool for geothermal exploration, but no FTG data had been acquired for geothermalmore » applications to date. Electromagnetic methods have been used for geothermal exploration for some time. The Z-Axis Tipper Electromagnetic (ZTEM) was a newer technology that had found success in mapping deep conductivity changes for mining applications. ZTEM had also been used in limited tests for geothermal exploration. This newer technology provided the ability to cost effectively map large areas whilst detailing the electrical properties of the geological structures at depths. The ZTEM is passive and it uses naturally occurring audio frequency magnetic (AFMAG) signals as the electromagnetic triggering source. These geophysical methods were to be tested over a known geothermal site to determine whether or not the data provided the information required for accurately interpreting the subsurface geologic structure associated with a geothermal deposit. After successful acquisition and analysis of the known source area, an additional survey of a “greenfield” area was to be completed. The final step was to develop a combined interpretation model and determine if the combination produced a higher confident geophysical model compared to models developed using each of the technologies individually.« less

Middle Jurassic incised valley fill (eolian/estuarine) and nearshore marine petroleum reservoirs, Powder River Basin

USGS Publications Warehouse

Ahlbrandt, T.S.; Fox, J.E.

1997-01-01

Paleovalleys incised into the Triassic Spearfish Formation (Chugwater equivalent) are filled with a vertical sequence of eolian, estuarine, and marine sandstones of the Middle Jurassic (Bathonian age) Canyon Springs Sandstone Member of the Sundance Formation. An outcrop exemplifying this is located at Red Canyon in the southern Black Hills, Fall River County, South Dakota. These paleovalleys locally have more than 300 ft of relief and are as much as several miles wide. Because they slope in a westerly direction, and Jurassic seas transgressed into the area from the west there was greater marine-influence and more stratigraphic complexity in the subsurface, to the west, as compared to the Black Hills outcrops. In the subsurface two distinctive reservoir sandstone beds within the Canyon Springs Sandstone Member fill the paleovalleys. These are the eolian lower Canyon Springs unit (LCS) and the estuarine upper Canyon Springs unit (UCS), separated by the marine "Limestone Marker" and estuarine "Brown Shale". The LCS and UCS contain significant proven hydrocarbon reservoirs in Wyoming (about 500 MMBO in-place in 9 fields, 188 MMBO produced through 1993) and are prospective in western South Dakota, western Nebraska and northern Colorado. Also prospective is the Callovian-age Hulett Sandstone Member which consists of multiple prograding shoreface to foreshore parasequences, as interpreted from the Red Canyon locality. Petrographic, outcrop and subsurface studies demonstrate the viability of both the Canyon Springs Sandstone and Hulett Sandstone members as superior hydrocarbon reservoirs in both stratigraphic and structural traps. Examples of fields with hydrocarbon production from the Canyon Springs in paleovalleys include Lance Creek field (56 MMBO produced) and the more recently discovered Red Bird field (300 MBO produced), both in Niobrara County, Wyoming. At Red Bird field the primary exploration target was the Pennsylvanian "Leo sands" of the Minnelusa Formation, and production from the Canyon Springs was not anticipated. Canyon Springs reservoirs are easily bypassed because they are relatively unconsolidated, underpressured, low-resistivity, and difficult to evaluate from petrophysics, drill-stem tests, or well cuttings.

Lunar and Martian Sub-surface Habitat Structure Technology Development and Application

NASA Technical Reports Server (NTRS)

Boston, Penelope J.; Strong, Janet D.

2005-01-01

NASA's human exploration initiative poses great opportunity and great risk for manned missions to the Moon and Mars. Subsidace structures such as caves and lava tubes offer readily available and existing in-situ habitat options. Sub-surface dwellings can provide complete radiation, micro-meteorite and exhaust plume shielding and a moderate and constant temperature environment; they are, therefore, excellent pre-existing habitat risk mitigation elements. Technical challenges to subsurface habitat structure development include surface penetration (digging and mining equipment), environmental pressurization, and psychological environment enhancement requirements. Lunar and Martian environments and elements have many beneficial similarities. This will allow for lunar testing and design development of subsurface habitat structures for Martian application; however, significant differences between lunar and Martian environments and resource elements will mandate unique application development. Mars is NASA's ultimate exploration goal and is known to have many very large lava tubes. Other cave types are plausible. The Moon has unroofed rilles and lava tubes, but further research will, in the near future, define the extent of Lunar and Martian differences and similarities. This paper will discuss Lunar and Martian subsurface habitation technology development challenges and opportunities.

JUICE: A European Mission to Jupiter and its Icy Moons

NASA Astrophysics Data System (ADS)

Grasset, Olivier; Witasse, Olivier; Barabash, Stas; Brandt, Pontus; Bruzzone, Lorenzo; Bunce, Emma; Cecconi, Baptiste; Cavalié, Thibault; Cimo, Giuseppe; Coustenis, Athena; Cremonese, Gabriele; Dougherty, Michele; Fletcher, Leigh N.; Gladstone, Randy; Gurvits, Leonid; Hartogh, Paul; Hoffmann, Holger; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Kasaba, Yasumasa; Kaspi, Yohai; Krupp, Norbert; Langevin, Yves; Mueller-Wodarg, Ingo; Palumbo, Pasquale; Piccioni, Giuseppe; Plaut, Jeffrey; Poulet, Francois; Roatsch, Thomas; Retherford, Kurt D.; Rothkaehl, Hanna; Stevenson, David J.; Tosi, Federico; Van Hoolst, Tim; Wahlund, Jan-Erik; Wurz, Peter; Altobelli, Nicolas; Accomazzo, A.; Boutonnet, Arnaud; Erd, Christian; Vallat, Claire

2016-10-01

JUICE - JUpiter ICy moons Explorer - is the first large mission in the ESA Cosmic Vision programme [1]. The implementation phase started in July 2015. JUICE will arrive at Jupiter in October 2029, and will spend 3 years characterizing the Jovian system, the planet itself, its giant magnetosphere, and the giant icy moons: Ganymede, Callisto and Europa. JUICE will then orbit Ganymede.The first goal of JUICE is to explore the habitable zone around Jupiter [2]. Ganymede is a high-priority target because it provides a unique laboratory for analyzing the nature, evolution and habitability of icy worlds, including the characteristics of subsurface oceans, and because it possesses unique magnetic fields and plasma interactions with the environment. On Europa, the focus will be on recently active zones, where the composition, surface and subsurface features (including putative water reservoirs) will be characterized. Callisto will be explored as a witness of the early Solar System.JUICE will also explore the Jupiter system as an archetype of gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere and ionosphere. JUICE will investigate the 3D properties of the magnetodisc, and study the coupling processes within the magnetosphere, ionosphere and thermosphere. The mission also focuses on characterizing the processes that influence surface and space environments of the moons.The payload consists of 10 instruments plus a ground-based experiment (PRIDE) to better constrain the S/C position. A remote sensing package includes imaging (JANUS) and spectral-imaging capabilities from UV to sub-mm wavelengths (UVS, MAJIS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the moons, and a radio science experiment (3GM) to probe the atmospheres and to determine the gravity fields. The in situ package comprises a suite to study plasma and neutral gas environments (PEP) with remote sensing capabilities via energetic neutrals, a magnetometer (J-MAG) and a radio and plasma wave instrument (RPWI). [1] JUICE Definition Study Report, ESA/SRE(2014)1. [2] Grasset et al., Plan. Space Sci., 78, 2013

Reconnecting tile drainage to riparian buffer hydrology for enhanced nitrate removal.

PubMed

Jaynes, D B; Isenhart, T M

2014-03-01

Riparian buffers are a proven practice for removing NO from overland flow and shallow groundwater. However, in landscapes with artificial subsurface (tile) drainage, most of the subsurface flow leaving fields is passed through the buffers in drainage pipes, leaving little opportunity for NO removal. We investigated the feasibility of re-routing a fraction of field tile drainage as subsurface flow through a riparian buffer for increasing NO removal. We intercepted an existing field tile outlet draining a 10.1-ha area of a row-cropped field in central Iowa and re-routed a fraction of the discharge as subsurface flow along 335 m of an existing riparian buffer. Tile drainage from the field was infiltrated through a perforated pipe installed 75 cm below the surface by maintaining a constant head in the pipe at a control box installed in-line with the existing field outlet. During 2 yr, >18,000 m (55%) of the total flow from the tile outlet was redirected as infiltration within the riparian buffer. The redirected water seeped through the 60-m-wide buffer, raising the water table approximately 35 cm. The redirected tile flow contained 228 kg of NO. On the basis of the strong decrease in NO concentrations within the shallow groundwater across the buffer, we hypothesize that the NO did not enter the stream but was removed within the buffer by plant uptake, microbial immobilization, or denitrification. Redirecting tile drainage as subsurface flow through a riparian buffer increased its NO removal benefit and is a promising management practice to improve surface water quality within tile-drained landscapes. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Extending RTM Imaging With a Focus on Head Waves

NASA Astrophysics Data System (ADS)

Holicki, Max; Drijkoningen, Guy

2016-04-01

Conventional industry seismic imaging predominantly focuses on pre-critical reflections, muting post-critical arrivals in the process. This standard approach neglects a lot of information present in the recorded wave field. This negligence has been partially remedied with the inclusion of head waves in more advanced imaging techniques, like Full Waveform Inversion (FWI). We would like to see post-critical information leave the realm of labour-intensive travel-time picking and tomographic inversion towards full migration to improve subsurface imaging and parameter estimation. We present a novel seismic imaging approach aimed at exploiting post-critical information, using the constant travel path for head-waves between shots. To this end, we propose to generalize conventional Reverse Time Migration (RTM) to scenarios where the sources for the forward and backward propagated wave-fields are not coinciding. RTM functions on the principle that backward propagated receiver data, due to a source at some locations, must overlap with the forward propagated source wave field, from the same source location, at subsurface scatterers. Where the wave-fields overlap in the subsurface there is a peak at the zero-lag cross-correlation, and this peak is used for the imaging. For the inclusion of head waves, we propose to relax the condition of coincident sources. This means that wave-fields, from non-coincident-sources, will not overlap properly in the subsurface anymore. We can make the wave-fields overlap in the subsurface again, by time shifting either the forward or backward propagated wave-fields until the wave-fields overlap. This is the same as imaging at non-zero cross-correlation lags, where the lag is the travel time difference between the two wave-fields for a given event. This allows us to steer which arrivals we would like to use for imaging. In the simplest case we could use Eikonal travel-times to generate our migration image, or we exclusively image the subsurface with the head wave from the nth-layer. To illustrate the method we apply it to a layered Earth model with five layers and compare it to conventional RTM. We will show that conventional RTM highlights interfaces, while our head-wave based images highlight layers, producing fundamentally different images. We also demonstrate that our proposed imaging scheme is more sensitive to the velocity model than conventional RTM, which is important for improved velocity model building in the future.

A Reversal of Decadal Trends in the Equatorial and North Indian Ocean

NASA Astrophysics Data System (ADS)

Thompson, P. R.; Merrifield, M. A.; McCreary, J. P., Jr.; Firing, E.; Piecuch, C. G.

2016-02-01

Sea level and upper ocean temperature trends in the Equatorial and North Indian Ocean (ENIO) reversed sign shortly after the turn of the century. The trend reversal is spatially coherent and characterized by subsurface cooling during 1993-2002 followed by subsurface warming during 2003-2012. Here we explore the dynamics and forcing of the decadal trend reversal, with a particular emphasis on the role of the Indian Ocean cross-equatorial cell (CEC) and anomalies transmitted from the Pacific basin to the ENIO via the Indonesian Throughflow (ITF). An examination of reanalysis wind-stress fields suggest that forcing of the CEC is enhanced during the cooling phase of the decadal fluctuation, which may account for the cooling trend below 100m in the ENIO during the first decade. In contrast, the subsurface warming during the second decade occurs at thermocline levels, which suggests a deepening of the thermocline during this period. Enhanced Pacific tradewinds since the early 1990s result in a deepening thermocline in the western tropical Pacific (WTP), which may be transmitted to the Indian Ocean basin via the ITF. We present results from simple model experiments that assess the potential for thermocline anomalies originating in the WTP to account for the deepening thermocline in the ENIO during the warming phase of the decadal fluctuation.

The Influence of Plant Root Systems on Subsurface Flow: Implications for Slope Stability

EPA Science Inventory

Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological m...

Prediction of hydrocarbon surface seepage potential using infiltrometer data

NASA Astrophysics Data System (ADS)

Connors, J. J.; Jackson, J. L.; Engle, R. A.; Connors, J. L.

2017-12-01

Environmental regulations addressing above-ground storage tank (AST) spill control activities typically require owners/operators to demonstrate that local soil permeability values are low enough to adequately contain released liquids while emergency-response procedures are conducted. Frequently, geotechnical borings and soil samples/analyses, and/or monitoring well slug-test analyses, are used to provide hydraulic conductivity data for the required calculations. While these techniques are useful in assessing hydrological characteristics of the subsurface, they do not always assess the uppermost surface soil layer, where the bulk of the containment can occur. This layer may have been subject to long-term permeability-reduction by activities such as compaction by vehicular and foot traffic, micro-coatings by hydrophobic pollutants, etc. This presentation explores the usefulness of dual-ring infiltrometers, both in field and bench-scale tests, to rapidly acquire actual hydraulic conductivity values of surficial soil layers, which can be much lower than subsurface values determined using more traditional downhole geotechnical and hydrogeological approaches.

ELF-VLF communications through the Earth Project report for calendar year 1984, revision 1

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burker, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-08-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constant of the rock, the noise characteristics, and the modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

ELF-VLF communications through-the-Earth

NASA Astrophysics Data System (ADS)

Buettner, H. M.; Burke, G. J.; Didwall, E. M.; Holladay, G.; Lytle, R. J.

1985-06-01

We use computer models and experiments to explore the feasibility of communication between points underground and on the Earth's surface. Emphasis is placed on ELF-VLF electromagnetic propagation through the Earth; nominally, we investigated propagation in the 200 Hz-30 kHz frequency range. The computer modeling included calculations of the fields of a point electric or magnetic source in a homogeneous half space or a stratified Earth. Initial results for an insulated antenna of finite length are also considered. The experiments involved through-the-Earth transmissions at two locations in Pennsylvania, both of which had large formations of limestone. Initial results indicate that information rates as high as kbits/s may be possible for subsurface depths of 300 m or less. Accuracy of these estimates depends on the electromagnetic propagation constants of the rock, the noise characteristics, and modulation scheme. Although a nuisance for evaluating through-the-Earth propagation, the existence of subsurface metal conductors can improve the transmission character of the site.

The Western Noachis Terra Chloride Deposits: An Improved Characterization of the Proposed Human Exploration Zone

NASA Astrophysics Data System (ADS)

Hill, J. R.; Plaut, J. J.; Christensen, P. R.

2016-12-01

At the First Landing Site and Exploration Zone Workshop for Human Missions to the Surface of Mars (Oct 27-30, 2015, Houston, TX), planetary scientists, students and members of the public proposed forty-seven sites that meet the engineering requirements for a human mission and would also allow astronauts to investigate important scientific questions while on the surface. The chloride deposits in western Noachis Terra at -37.2°N, 350.5°E were proposed as a potential exploration zone due to their proximity to craters containing glacier-like forms and imperfectly-formed concentric crater fill. The high astrobiological preservation potential of the chloride deposits exposed on the surface would allow astronauts to investigate the past habitability of a well-preserved Noachian fluvial system, while the subsurface ice features suggest astronauts would have relatively easy access to enough water to meet the requirements of NASA's current baseline mission architecture. Since the workshop, the proposed exploration zone has been further characterized using additional datasets, as well as new data collected by the Mars Reconnaissance Orbiter as part of the exploration zone data acquisition effort organized by NASA's Human Landing Sites Study (HLS2) team. First, SHARAD radar data were used to constrain the subsurface structure of the imperfectly-formed concentric crater fill within the two large craters, which makes a more accurate assessment of the potential subsurface water ice resources possible. Second, newly acquired HiRISE images were used to better assess the traversability of the terrain between the habitation zone and the primary resource and science regions-of-interest (ROIs). And third, the exploration zone was shifted in order to place the central landing site closer to potential subsurface water ice resources. Although this would require crews to travel further to investigate the chloride deposits, it reduces the distance between the subsurface water ice locations and the central habitation zone, where the excavated water would be processed and utilized. The analysis of this additional data has further demonstrated that the western Noachis Terra chloride deposits are an ideal location for astronauts to safely and effectively conduct astrobiological investigations on the Martian surface.

Enhanced Structural Interpretation Using Multitrace Seismic Attribute For Oligo-Miocene Target at Madura Strait Offshore

NASA Astrophysics Data System (ADS)

Pratama Wahyu Hidayat, Putra; Hary Murti, Antonius; Sudarmaji; Shirly, Agung; Tiofan, Bani; Damayanti, Shinta

2018-03-01

Geometry is an important parameter for the field of hydrocarbon exploration and exploitation, it has significant effect to the amount of resources or reserves, rock spreading, and risk analysis. The existence of geological structure or fault becomes one factor affecting geometry. This study is conducted as an effort to enhance seismic image quality in faults dominated area namely offshore Madura Strait. For the past 10 years, Oligo-Miocene carbonate rock has been slightly explored on Madura Strait area, the main reason because migration and trap geometry still became risks to be concern. This study tries to determine the boundary of each fault zone as subsurface image generated by converting seismic data into variance attribute. Variance attribute is a multitrace seismic attribute as the derivative result from amplitude seismic data. The result of this study shows variance section of Madura Strait area having zero (0) value for seismic continuity and one (1) value for discontinuity of seismic data. Variance section shows the boundary of RMKS fault zone with Kendeng zone distinctly. Geological structure and subsurface geometry for Oligo-Miocene carbonate rock could be identified perfectly using this method. Generally structure interpretation to identify the boundary of fault zones could be good determined by variance attribute.

A new solar cycle model including meridional circulation

NASA Technical Reports Server (NTRS)

Wang, Y.-M.; Sheeley, N. R., Jr.; Nash, A. G.

1991-01-01

A kinematic model is presented for the solar cycle which includes not only the transport of magnetic flux by supergranular diffusion and a poleward bulk flow at the sun's surface, but also the effects of turbulent diffusion and an equatorward 'return flow' beneath the surface. As in the earlier models of Babcock and Leighton, the rotational shearing of a subsurface poloidal field generates toroidal flux that erupts at the surface in the form of bipolar magnetic regions. However, such eruptions do not result in any net loss of toroidal flux from the sun (as assumed by Babcock and Leighton); instead, the large-scale toroidal field is destroyed both by 'unwinding' as the local poloidal field reverses its polarity, and by diffusion as the toroidal flux is transported equatorward by the subsurface flow and merged with its opposite hemisphere counterpart. The inclusion of meridional circulation allows stable oscillations of the magnetic field, accompanied by the equatorward progression of flux eruptions, to be achieved even in the absence of a radial gradient in the angular velocity. An illustrative case in which a subsurface flow speed of order 1 m/s and subsurface diffusion rate of order 10 sq km/s yield 22-yr oscillations in qualitative agreement with observations.

Performance of Subsurface Tube Drainage System in Saline Soils: A Case Study

NASA Astrophysics Data System (ADS)

Pali, A. K.

2015-06-01

In order to improve the saline and water logged soils caused due to groundwater table rise, installation of subsurface drainage system is considered as one of the best remedies. However, the design of the drainage system has to be accurate so that the field performance results conform to the designed results. In this investigation, the field performance of subsurface tube drainage system installed at the study area was evaluated. The performance was evaluated on the basis of comparison of the designed value of water table drop as 30 cm after 2 days of drainage and predicted and field measured hydraulic heads for a consecutive drainage period of 14 days. The investigation revealed that the actual drop of water table after 2 days of drainage was 25 cm, about 17 % less than the designed value of 30 cm after 2 days of drainage. The comparison of hydraulic heads predicted by Van Schilfgaarde equation of unsteady drainage with the field-measured hydraulic heads showed that the deviation of predicted hydraulic heads varied within a range of ±8 % indicating high acceptability of Van Schlifgaarde equation for designing subsurface drainage system in saline and water logged soils resembling to that of the study area.

Exobiological Exploration of Europa (E3) Europa Lander

NASA Technical Reports Server (NTRS)

Stillwagen, F. H.; Manvi, Ramachandra; Seywald, Hans; Park, Sang-Young; Kolacinski, Rick

2002-01-01

The search for life outside Earth's protected atmosphere is a compelling testament to the quest by mankind to determine if "we" are alone in the universe. The phenomenal success of the NASA Galileo spacecraft has indicated that the moons of Jupiter, and most notably Europa, may indeed contain subsurface liquid under an icy surface. This speculation of a salty liquid subsurface fuels expert opinions that biological products may exist. The Revolutionary Aerospace Systems Concepts (RASC) effort at Langley Research Center, initiated by NASA Headquarters, pushes NASA and the Aerospace/Science community to target advanced evolutionary technology usage to provide a Europa Lander concept targeted for completion within the next 50 years. The study effort indicates the use of certain advanced technologies to achieve a subsurface penetrator and liquid explorer in the approximately 2040 timeframe.

Boom, Doom and Rocks - The Intersection of Physics, Video Games and Geology

NASA Astrophysics Data System (ADS)

McBride, J. H.; Keach, R. W.

2008-12-01

Geophysics is a field that incorporates the rigor of physics with the field methods of geology. The onset and rapid development of the computer games that students play bring new hardware and software technologies that significantly improve our understanding and research capabilities. Together they provide unique insights to the subsurface of the earth in ways only imagined just a few short years ago. 3D geological visualization has become an integral part of many petroleum industry exploration efforts. This technology is now being extended to increasing numbers of universities through grants from software vendors. This talk will explore 3D visualization techniques and how they can be used for both teaching and research. Come see examples of 3D geophysical techniques used to: image the geology of ancient river systems off the coast of Brazil and in the Uinta Basin of Utah, guide archaeological excavations on the side of Mt. Vesuvius, Italy, and to study how volcanoes were formed off the coast of New Zealand.

Characterizing the deformation of reservoirs using interferometry, gravity, and seismic analyses

NASA Astrophysics Data System (ADS)

Schiek, Cara Gina

In this dissertation, I characterize how reservoirs deform using surface and subsurface techniques. The surface technique I employ is radar interferometry, also known as InSAR (Interferometric Synthetic Aperture Radar). The subsurface analyses I explore include gravity modeling and seismic techniques consisting of determining earthquake locations from a small-temporary seismic network of six seismometers. These techniques were used in two different projects to determine how reservoirs deform in the subsurface and how this deformation relates to its remotely sensed surface deformation. The first project uses InSAR to determine land subsidence in the Mimbres basin near Deming, NM. The land subsidence measurements are visually compared to gravity models in order to determine the influence of near surface faults on the subsidence and the physical properties of the aquifers in these basins. Elastic storage coefficients were calculated for the Mimbres basin to aid in determining the stress regime of the aquifers. In the Mimbres basin, I determine that it is experiencing elastic deformation at differing compaction rates. The west side of the Mimbres basin is deforming faster, 17 mm/yr, while the east side of the basin is compacting at a rate of 11 mm/yr. The second project focuses on San Miguel volcano, El Salvador. Here, I integrate InSAR with earthquake locations using surface deformation forward modeling to investigate the explosive volcanism in this region. This investigation determined the areas around the volcano that are undergoing deformation, and that could lead to volcanic hazards such as slope failure from a fractured volcano interior. I use the earthquake epicenters with field data to define the subsurface geometry of the deformation source, which I forward model to produce synthetic interferograms. Residuals between the synthetic and observed interferograms demonstrate that the observed deformation is a direct result of the seismic activity along the San Miguel Fracture Zone. Based on the large number of earthquakes concentrated in this region and the fracturing suggested by the earthquake location results, I conclude that the southwestern slope of San Miguel is the most susceptible to volcanic hazards such as landsliding and flank lava flows. Together these projects explore the dynamics of reservoir systems, both hydrologic and magmatic. They show the utility of geodetic remote sensing to constrain the relative importance of various, complex, subsurface processes, including faulting, fluid migration, and compaction.

Removal of microbial pathogens in a sandy gravel aquifer under forced-gradient subsurface flow conditions

NASA Astrophysics Data System (ADS)

Oudega, Thomas James; Derx, Julia; van Driezum, Inge; Cisneros, Anibal; Sommer, Regina; Kirschner, Alexander; Farnleitner, Andreas; Blaschke, Alfred Paul

2017-04-01

Subsurface media are being used around the world as a means to mitigate microbial contamination, but vary widely in their ability to remove pathogens. To help to provide accurate risk assessments of microbial contamination of groundwaters, and establish safe setback distances between receiving waters and disposal fields, this study aims to use aquifer tracer tests to evaluate the ability of subsurface media to attenuate these pathogens. The novelty of this work is the use of a variety of different tracer substances (e.g. phages, spores, microspheres, conservative tracers) together in field experiments. This will be done by means of injecting these substances under a forced gradient in a sandy gravel aquifer in Lobau, Austria. The extraction of the tracers will be monitored in a pumping well at a distrance of 50m downgradient. This will be able to provide us with insight to the characteristics of microbial transport and how the microorganisms react to the subsurface in the study site. Subsequent numerical modelling of the experiments can tell us more about quantification of subsurface processes such as attachment/detachment, inactivation and die-off of these substances. The first field experiment with conservative tracers (NaCl) has been carried out in December 2016, and subsequent tests are being planned for the next months.

Researchers Mine Information from Next-Generation Subsurface Flow Simulations

DOE PAGES

Gedenk, Eric D.

2015-12-01

A research team based at Virginia Tech University leveraged computing resources at the US Department of Energy's (DOE's) Oak Ridge National Laboratory to explore subsurface multiphase flow phenomena that can't be experimentally observed. Using the Cray XK7 Titan supercomputer at the Oak Ridge Leadership Computing Facility, the team took Micro-CT images of subsurface geologic systems and created two-phase flow simulations. The team's model development has implications for computational research pertaining to carbon sequestration, oil recovery, and contaminant transport.

Chemical and microbiological water quality of subsurface agricultural drains during a field trial of liquid dairy manure effluent application rate and varying tillage practices, Upper Tiffin Watershed, southeastern Michigan

USGS Publications Warehouse

Haack, Sheridan Kidd; Duris, Joseph W.

2008-01-01

A field trial was done in the Upper Tiffin River Watershed, in southeastern Michigan, to determine the influence of liquid dairy manure effluent (LDME) management practices on the quality of agricultural subsurface-drain water. Samples from subsurface drains were analyzed for nutrients, fecal-coliform and Escherichia coli (E. coli) bacteria, antibiotics, chemicals typically detected in wastewater, and the occurrence of genes indicating the presence of shiga-toxin-producing E. coli, or of bovine-specific Bacteroidetes bacteria. Samples were collected from November 2, 2006, to March 20, 2007, from eight subsurface drains under field plots that received no LDME and no tillage (controls) or received 4,000 or 8,000 gallons per acre (gal/acre) of LDME and either no tillage or two different types of tillage. The two types of tillage tested were (1) ground-driven, rotary, subsurface cultivation and (2) rolling-tine aeration. Samples were collected before LDME application and at 4 hours, and 1, 2, 6, 7, and 14 days post-application. Nutrient concentrations were high in subsurface-drain water throughout the field-trial period and could not be attributed to the field-trial LDME application. Of the 59 drain-water samples, including those collected before LDME application and control samples for each date, 56 had concentrations greater than the U.S. Environmental Protection Agency (USEPA), Ecoregion VI recommended surface-water criterion for total phosphorus, and all samples had concentrations greater than the recommended total nitrogen criterion. Nitrate + nitrite nitrogen concentration exceeded 20 milligrams per liter for every sample and contributed most to the total nitrogen concentrations. Substantial increases in drain-water concentrations of organic and ammonia nitrogen and total phosphorus were found for all treatments, including controls, at 14 days post-application after 0.84 inch of rainfall over 2 days. E. coli concentrations exceeded the USEPA recreational-water-quality single-sample criterion of 235 colony forming units per 100 milliliters in only 3 of 56 samples. Of these three samples, two were collected within 1 day post-LDME application from the treatment receiving 8,000 gal/acre LDME with no tillage (NT8000). The third sample was from the rolling-tine aerator treatment with 4,000 gal/acre LDME application rate after the first significant rainfall. Two wastewater chemicals and two bacterial genes (eaeA and stx1) detected in the LDME, but absent in field blank or pre-application samples, were detected in the 4-hour or 1-day postapplication NT8000 samples. No LDME-associated chemicals were detected in later samples from the NT8000 treatment, and none were detected in samples from other treatments after the first significant rainfall. Results of this field trial were somewhat equivocal with respect to the influence of LDME concentration and tillage practices on subsurface-drain water quality, both immediately after LDME application and in the longer term, after significant rainfall. Interpretation of study findings is limited by the fact that treatments were not replicated, and flow rate or discharge from the subsurface drains was not measured. Nevertheless, study results provide useful information about nutrient and bacteria concentrations in subsurface drains during the non-growing season. In addition, study results demonstrate some potential for the use of chemical and microbiological indicators of LDME transport to subsurface drains.

Contributions to a shallow aquifer study by reprocessed seismic sections from petroleum exploration surveys, eastern Abu Dhabi, United Arab Emirates

USGS Publications Warehouse

Woodward, D.

1994-01-01

The US Geological Survey, in cooperation with the National Drilling Company of Abu Dhabi, is conducting a 4-year study of the fresh and slightly saline groundwater resources of the eastern Abu Dhabi Emirate. Most of this water occurs in a shallow aquifer, generally less than 150 m deep, in the Al Ain area. A critical part of the Al Ain area coincides with a former petroleum concession area where about 2780 km of vibroseis data were collected along 94 seismic lines during 1981-1983. Field methods, acquistion parameters, and section processing were originally designed to enhance reflections expected at depths ranging from 5000 to 6000 m, and subsurface features directly associated with the shallow aquifer system were deleted from the original seismic sections. The original field tapes from the vibroseis survey were reprocessed in an attempt to extract shallow subsurface information (depths less than 550 m) for investigating the shallow aquifer. A unique sequence of reproccessing parameters was established after reviewing the results from many experimental tests. Many enhancements to the resolution of shallow seismic reflections resulted from: (1) application of a 20-Hz, low-cut filter; (2) recomputation of static corrections to a datum nearer the land surface; (3) intensive velocity analyses; and (4) near-trace muting analyses. The number, resolution, and lateral continuity of shallow reflections were greatly enhanced on the reprocessed sections, as was the delineation of shallow, major faults. Reflections on a synthetic seismogram, created from a borehole drilled to a depth of 786 m on seismic line IQS-11, matcheddprecisely with shallow reflections on the reprocessed section. The 33 reprocessed sections were instrumental in preparing a map showing the major structural features that affect the shallow aquifer system. Analysis of the map provides a better understanding of the effect of these shallow features on the regional occurrence, movement, and quality of groundwater in the concession area. Results from this study demonstrate that original seismic field tapes collected for deep petroleum exploration can be reprocessed to explore for groundwater. ?? 1994.

Tetracycline Resistance in the Subsurface of a Poultry Farm: Influence of Poultry Wastes

NASA Astrophysics Data System (ADS)

You, Y.; Ball, W. P.; Ward, M. J.; Hilpert, M.

2007-12-01

Concentrated animal feeding operations (CAFOs) are considered to be important man-made reservoir of antibiotic resistant bacteria. Using the electromagnetic induction (EMI) method of geophysical characterization, we measured the apparent subsurface electrical conductivity (ECa) at a CAFO site in order to assess the movement of pollutants associated with animal waste. The map of ECa and other available data suggest that (1) soil surrounding a poultry litter storage shed is contaminated by poultry waste, (2) a contamination plume in the subsurface emanates from that shed, and (3) the development of that plume is due to groundwater flow. We focused on understanding the spread of tetracycline resistance (Tc\\tiny R), because tetracycline is one of the most frequently used antibiotics in food animal production and therefore probably used at our field site. Microbiological experiments show the presence of Tc\\tiny R bacteria in the subsurface and indicate higher concentrations in the top soil than in the aquifer. Environmental DNA was extracted to identify CAFO- associated Tc\\tiny R genes and to explore a link between the presence of Tc\\tiny R and CAFO practices. A "shot-gun" cloning approach is under development to target the most prevalent Tc\\tiny R gene. This gene will be monitored in future experiments, in which we will study the transmission of Tc\\tiny R to naive E.~coli under selective pressure of Tc. Experimental results will be used to develop a mathematical/numerical model in order to describe the transmission process and to subsequently make estimates regarding the large-scale spread of antibiotic resistance.

Application of a fully integrated surface-subsurface physically based flow model for evaluating groundwater recharge from a flash flood event

NASA Astrophysics Data System (ADS)

Pino, Cristian; Herrera, Paulo; Therrien, René

2017-04-01

In many arid regions around the world groundwater recharge occurs during flash floods. This transient spatially and temporally concentrated flood-recharge process takes place through the variably saturated zone between surface and usually the deep groundwater table. These flood events are characterized by rapid and extreme changes in surface flow depth and velocity and soil moisture conditions. Infiltration rates change over time controlled by the hydraulic gradients and the unsaturated hydraulic conductivity at the surface-subsurface interface. Today is a challenge to assess the spatial and temporal distribution of groundwater recharge from flash flood events under real field conditions at different scales in arid areas. We apply an integrated surface-subsurface variably saturated physically-based flow model at the watershed scale to assess the recharge process during and after a flash flood event registered in an arid fluvial valley in Northern Chile. We are able to reproduce reasonably well observed groundwater levels and surface flow discharges during and after the flood with a calibrated model. We also investigate the magnitude and spatio-temporal distribution of recharge and the response of the system to variations of different surface and subsurface parameters, initial soil moisture content and groundwater table depths and surface flow conditions. We demonstrate how an integrated physically based model allows the exploration of different spatial and temporal system states, and that the analysis of the results of the simulations help us to improve our understanding of the recharge processes in similar type of systems that are common to many arid areas around the world.

Application of Electrical Resistivity Method (ERM) in Groundwater Exploration

NASA Astrophysics Data System (ADS)

Izzaty Riwayat, Akhtar; Nazri, Mohd Ariff Ahmad; Hazreek Zainal Abidin, Mohd

2018-04-01

The geophysical method which dominant by geophysicists become one of most popular method applied by engineers in civil engineering fields. Electrical Resistivity Method (ERM) is one of geophysical tool that offer very attractive technique for subsurface profile characterization in larger area. Applicable alternative technique in groundwater exploration such as ERM which complement with existing conventional method may produce comprehensive and convincing output thus effective in terms of cost, time, data coverage and sustainable. ERM has been applied by various application in groundwater exploration. Over the years, conventional method such as excavation and test boring are the tools used to obtain information of earth layer especially during site investigation. There are several problems regarding the application of conventional technique as it only provides information at actual drilling point only. This review paper was carried out to expose the application of ERM in groundwater exploration. Results from ERM could be additional information to respective expert for their problem solving such as the information on groundwater pollution, leachate, underground and source of water supply.

Seismic fiber optic multiplexed sensors for exploration and reservoir management

NASA Astrophysics Data System (ADS)

Houston, Mark H.

2000-12-01

Reliable downhole communications, control and sensor networks will dramatically improve oil reservoir management practices and will enable the construction of intelligent or smart-well completions. Fiber optic technology will play a key role in the implementation of these communication, control and sensing systems because of inherent advantages of power, weight and reliability over more conventional electronic-based systems. Field test data, acquired using an array of fiber optic seismic hydrophones within a steam-flood, heavy oil- production filed, showed a significant improvement (10X in this specific case) in subsurface resolution as compared to conventional surface seismic acquisition. These results demonstrate the viability of using multiplexed fiber optic sensors for exploration and reservoir management in 3D vertical seismic profiling (VSP) surveys and in permanent sensor arrays for 4D surveys.

Effects of Droplet Size on Intrusion of Sub-Surface Oil Spills

NASA Astrophysics Data System (ADS)

Adams, Eric; Chan, Godine; Wang, Dayang

2014-11-01

We explore effects of droplet size on droplet intrusion and transport in sub-surface oil spills. Negatively buoyant glass beads released continuously to a stratified ambient simulate oil droplets in a rising multiphase plume, and distributions of settled beads are used to infer signatures of surfacing oil. Initial tests used quiescent conditions, while ongoing tests simulate currents by towing the source and a bottom sled. Without current, deposited beads have a Gaussian distribution, with variance increasing with decreasing particle size. Distributions agree with a model assuming first order particle loss from an intrusion layer of constant thickness, and empirically determined flow rate. With current, deposited beads display a parabolic distribution similar to that expected from a source in uniform flow; we are currently comparing observed distributions with similar analytical models. Because chemical dispersants have been used to reduce oil droplet size, our study provides one measure of their effectiveness. Results are applied to conditions from the `Deep Spill' field experiment, and the recent Deepwater Horizon oil spill, and are being used to provide ``inner boundary conditions'' for subsequent far field modeling of these events. This research was made possible by grants from Chevron Energy Technology Co., through the Chevron-MITEI University Partnership Program, and BP/The Gulf of Mexico Research Initiative, GISR.

Tecuamburro Volcano, Guatemala: exploration geothermal gradient drilling and results

USGS Publications Warehouse

Goff, S.J.; Goff, F.; Janik, C.J.

1992-01-01

Results of geological, volcanological, hydrogeochemical, and geophysical field studies conducted in 1988 and 1989 at the Tecuamburro geothermal site, Guatemala, indicate that there is a substantial shallow heat source beneath the area of youngest volcanism. Gases from acid-sulfate springs near Laguna Ixpaco consistently yield maximum estimated subsurface temperatures of 300??C. To obtain information on subsurface temperatures and temperature gradients, stratigraphy, fracturing, hydrothermal alteration, and hydrothermal fluids, a geothermal gradient core hole (TCB-1) was drilled to 808 m low on the northern flank of the Tecuamburro Volcano complex. The hole is located 300 m south of a 300m-diameter phreatic crater. Laguna Ixpaco, dated at 2910 years. TCB-1 temperature logs do not indicate isothermal conditions at depth and the calculated thermal gradient from 500-800 m is 230??C/km. Bottom hole temperature is close to 240??C. Calculated heat flow values are around 350-400 mW/m2. Fluid-inclusion and secondary-alteration studies indicate that veins and secondary minerals were formed at temperatures equal to or slightly less than present temperatures; thus, the Tecuamburro geothermal system may still be heating up. The integration of results from the TCB-1 gradient core hole with results from field studies provides strong evidence that the Tecuamburro area holds great promise for geothermal resource development. ?? 1992.

Geophysical Exploration Technologies for the Deep Lithosphere Research: An Education Materials for High School Students

NASA Astrophysics Data System (ADS)

Xu, H.; Xu, C.; Luo, S.; Chen, H.; Qin, R.

2012-12-01

The science of Geophysics applies the principles of physics to study of the earth. Geophysical exploration technologies include the earthquake seismology, the seismic reflection and refraction methods, the gravity method, the magnetic method and the magnetotelluric method, which are used to measure the interior material distribution, their structure and the tectonics in the lithosphere of the earth. Part of the research project in SinoProbe-02-06 is to develop suitable education materials for carton movies targeting the high school students and public. The carton movies include five parts. The first part includes the structures of the earth's interior and variation in their physical properties that include density, p-wave, s-wave and so on, which are the fundamentals of the geophysical exploration technologies. The second part includes the seismology that uses the propagation of elastic waves through the earth to study the structure and the material distribution of the earth interior. It can be divided into earthquake seismology and artifice seismics commonly using reflection and refraction. The third part includes the magnetic method. Earth's magnetic field (also known as the geomagnetic field)extends from the Earth's inner core to where it meets the solar wind, a stream of energetic particles emanating from the Sun. The aim of magnetic survey is to investigate subsurface geology on the basis of anomalies in the Earth's magnetic field resulting from the magnetic properties of the underlying rocks. The magnetic method in the lithosphere attempts to use magnetic disturbance to analyse the regional geological structure and the magnetic boundaries of the crust. The fourth part includes the gravity method. A gravity anomaly results from the inhomogeneous distribution of density of the Earth. Usually gravity anomalies contain superposed anomalies from several sources. The long wave length anomalies due to deep density contrasts are called regional anomalies. They are important for understanding the large-scale structure of the earth's crust under major geographic features, such as mountain ranges, oceanic ridges and subduction zones. Short wave length residual anomalies are due to shallow anomalous masses that may be of interest for commercial exploitation. The last part is the magnetotellurics (MT), which is an electromagnetic geophysical method of imaging the earth's subsurface by measuring natural variations of electrical and magnetic fields at the Earth's surface. The long-period MT technique is used to exploration deep crustal. MT has been used to investigate the distribution of silicate melts in the Earth's mantle and crust and to better understand the plate-tectonic processes.

How does subsurface retain and release stored water? An explicit estimation of young water fraction and mean transit time

NASA Astrophysics Data System (ADS)

Ameli, Ali; McDonnell, Jeffrey; Laudon, Hjalmar; Bishop, Kevin

2017-04-01

The stable isotopes of water have served science well as hydrological tracers which have demonstrated that there is often a large component of "old" water in stream runoff. It has been more problematic to define the full transit time distribution of that stream water. Non-linear mixing of previous precipitation signals that is stored for extended periods and slowly travel through the subsurface before reaching the stream results in a large range of possible transit times. It difficult to find tracers can represent this, especially if all that one has is data on the precipitation input and the stream runoff. In this paper, we explicitly characterize this "old water" displacement using a novel quasi-steady physically-based flow and transport model in the well-studied S-Transect hillslope in Sweden where the concentration of hydrological tracers in the subsurface and stream has been measured. We explore how subsurface conductivity profile impacts the characteristics of old water displacement, and then test these scenarios against the observed dynamics of conservative hydrological tracers in both the stream and subsurface. This work explores the efficiency of convolution-based approaches in the estimation of stream "young water" fraction and time-variant mean transit times. We also suggest how celerity and velocity differ with landscape structure

Summary of the Issues Regarding The Martian Subsurface Explorer

NASA Technical Reports Server (NTRS)

Eustes, A. W., III; Gertsch, L. S.; Lu, N.; Bridgford, E.; Tischler, A.; Stoner, M. S.; Wilcox, B. H.

2000-01-01

This is a summary of research work accomplished to date for the Jet Propulsion Laboratory by the Colorado School of Mines and the Michigan Technological University for the Martian Subsurface Explorer (SSX). The task involved a thorough review of the state of the art in drilling in the petroleum and mining industries in the following areas: 1) Drilling mechanics and energy requirements. 2) Sidewall friction in boreholes. 3) Rock property characteristics of basalt, permafrost, and ice. 4) Cuttings transport and recompaction of cuttings. and 5) Directional control at odd angle interfaces.

Subsurface application enhances benefits of manure redistribution

USDA-ARS?s Scientific Manuscript database

Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic and environmental effects of different poultry litter application methods (surface vs. subsurface) and timings (fall ...

Nutrient loss in leachate and surface runoff from surface-broadcast and subsurface-banded broiler litter.

PubMed

Lamba, Jasmeet; Srivastava, Puneet; Way, Thomas R; Sen, Sumit; Wood, C Wesley; Yoo, Kyung H

2013-09-01

Subsurface band application of poultry litter has been shown to reduce the transport of nutrients from fields in surface runoff compared with conventional surface broadcast application. Little research has been conducted to determine the effects of surface broadcast application and subsurface banding of litter on nutrients in leachate. Therefore, a field experiment was conducted to determine the effects of subsurface band application and surface broadcast application of poultry litter on nutrient losses in leachate. Zero-tension pan and passive capillary fiberglass wick lysimeters were installed in situ 50 cm beneath the soil surface of an established tall fescue ( Schreb.) pasture on a sandy loam soil. The treatments were surface broadcast and subsurface-banded poultry litter at 5 Mg ha and an unfertilized control. Results of the rainfall simulations showed that the concentrations of PO-P and total phosphorus (TP) in leachate were reduced by 96 and 37%, respectively, in subsurface-banded litter treatment compared with the surface-applied litter treatment. There was no significant difference in PO-P concentration between control and subsurface-banded litter treatment in leachate. The trend in the loading of nutrients in leachate was similar to the trend in concentration. Concentration and loading of the nutrients (TP, PO-P, NH-N, and NO-N) in runoff from the subsurface-banded treatment were significantly less than for the surface-applied treatment and were similar to those from control plots. These results show that, compared with conventional surface broadcast application of litter, subsurface band application of litter can greatly reduce loss of P in surface runoff and leachate. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

PERCIVAL mission to Mars

NASA Astrophysics Data System (ADS)

Reed, David W.; Lilley, Stewart; Sirman, Melinda; Bolton, Paul; Elliott, Susan; Hamilton, Doug; Nickelson, James; Shelton, Artemus

1992-12-01

With the downturn of the world economy, the priority of unmanned exploration of the solar system has been lowered. Instead of foregoing all missions to our neighbors in the solar system, a new philosophy of exploration mission design has evolved to insure the continued exploration of the solar system. The 'Discovery-class' design philosophy uses a low cost, limited mission, available technology spacecraft instead of the previous 'Voyager-class' design philosophy that uses a 'do-everything at any cost' spacecraft. The Percival Mission to Mars was proposed by Ares Industries as one of the new 'Discovery-class' of exploration missions. The spacecraft will be christened Percival in honor of American astronomer Percival Lowell who proposed the existence of life on Mars in the early twentieth century. The main purpose of the Percival mission to Mars is to collect and relay scientific data to Earth suitable for designing future manned and unmanned missions to Mars. The measurements and observations made by Percival will help future mission designers to choose among landing sites based on the feasibility and scientific interest of the sites. The primary measurements conducted by the Percival mission include gravity field determination, surface and atmospheric composition, sub-surface soil composition, sub-surface seismic activity, surface weather patterns, and surface imaging. These measurements will be taken from the orbiting Percival spacecraft and from surface penetrators deployed from Mars orbit. The design work for the Percival Mission to Mars was divided among four technical areas: Orbits and Propulsion System, Surface Penetrators, Gravity and Science Instruments, and Spacecraft Structure and Systems. The results for each of the technical areas is summarized and followed by a design cost analysis and recommendations for future analyses.

PERCIVAL mission to Mars

NASA Technical Reports Server (NTRS)

Reed, David W.; Lilley, Stewart; Sirman, Melinda; Bolton, Paul; Elliott, Susan; Hamilton, Doug; Nickelson, James; Shelton, Artemus

1992-01-01

With the downturn of the world economy, the priority of unmanned exploration of the solar system has been lowered. Instead of foregoing all missions to our neighbors in the solar system, a new philosophy of exploration mission design has evolved to insure the continued exploration of the solar system. The 'Discovery-class' design philosophy uses a low cost, limited mission, available technology spacecraft instead of the previous 'Voyager-class' design philosophy that uses a 'do-everything at any cost' spacecraft. The Percival Mission to Mars was proposed by Ares Industries as one of the new 'Discovery-class' of exploration missions. The spacecraft will be christened Percival in honor of American astronomer Percival Lowell who proposed the existence of life on Mars in the early twentieth century. The main purpose of the Percival mission to Mars is to collect and relay scientific data to Earth suitable for designing future manned and unmanned missions to Mars. The measurements and observations made by Percival will help future mission designers to choose among landing sites based on the feasibility and scientific interest of the sites. The primary measurements conducted by the Percival mission include gravity field determination, surface and atmospheric composition, sub-surface soil composition, sub-surface seismic activity, surface weather patterns, and surface imaging. These measurements will be taken from the orbiting Percival spacecraft and from surface penetrators deployed from Mars orbit. The design work for the Percival Mission to Mars was divided among four technical areas: Orbits and Propulsion System, Surface Penetrators, Gravity and Science Instruments, and Spacecraft Structure and Systems. The results for each of the technical areas is summarized and followed by a design cost analysis and recommendations for future analyses.

Field evaluations of "ShapeAccelArray" in-place MEMS inclinometer strings for subsurface deformation monitoring.

DOT National Transportation Integrated Search

2012-03-01

Continuous monitoring of subsurface ground movements is accomplished with in-place instruments utilizing automated data acquisition methods. These typically include TDR (Time Domain Reflectometry) or assemblies of several servo-accelerometer-based, e...

OVERVIEW -- SUBSURFACE PROTECTION AND REMEDIATION DIVISION

EPA Science Inventory

NRMRL's Subsurface Protection and Remediation Division located in Ada, Oklahoma, conducts EPA-investigator led laboratory and field research to provide the scientific basis to support the development of strategies and technologies to protect and restore ground and surface water q...

Stormflow generation: a meta-analysis of field studies and research catchments

NASA Astrophysics Data System (ADS)

Barthold, Frauke; Elsenbeer, Helmut

2014-05-01

Runoff characteristics are expressions of runoff generation mechanisms. In this study, we want to test the hypothesis if storm hydrographs of catchments with prevailing near-surface flow paths are dominated by new water. We aim to test this hypothesis using published data from the scientific literature. We developed a classification system based on three runoff characteristics: (1) hydrograph response (HR: slowly or quickly), (2) the temporal source of water that dominates the hydrograph (TS: pre-event vs. event water) and (3) the flow paths that the water takes until it is released to the stream (FP: subsurface vs. surface flow paths). We then performed a literature survey to collect information on these runoff characteristics for small, forested headwater catchments that served as study areas in runoff generation studies and assigned each study catchment to one of the 8 classes. For this purpose, we designed a procedure to objectively diagnose the predominant conceptual model of storm flow generation in each catchment and assess its temporal and spatial relevance for the catchment. Finally, we performed an explorative analysis of the classified research catchments and summarized field evidence. Our literature survey yielded a sample of 22 research catchments that fell within our defined criteria (small, naturally forested catchments which served as study areas in stormflow generation studies). We applied our classification procedure to all of these catchments. Among them were 14 catchments for which our meta-analysis yielded a complete set of stormflow characteristics resulting in one of the 8 model concepts and were assigned into our classification scheme. Of the 14 classified research catchments, 10 were dominated by subsurface flow paths while 4 were dominated by overland flow. The data also indicate that the spatial and temporal relevance is high for catchments with subsurface flow paths while often weak for surface flow paths dominated catchments. The catalogue of catchments supports our hypothesis; however, it is afflicted with a relative high degree of uncertainty. Two theories exist that may explain the imbalance between surface and subsurface dominated catchments: (1) the selection of research sites for stormflow generation studies was guided by the leading research question in hydrology, i.e. to address the "old water paradox", and (2) catchments with prevailing subsurface flow paths are much more common in nature. In a next step, the proposed catalogue of research catchments allows correlation of environmental characteristics with runoff characteristics to address questions of catchment organization and similarity. However, the successful application and relevance of such an approach depends on the range of conceptual models for which field support exist. Our results prompt us to highlight future research needs: (1) in order to cover a broader range of combinations of runoff characteristics a careful selection of research sites is necessary and (2) propose guidelines for field studies in order achieve higher comparability of resulting conceptual models of research sites and increase the spatial and temporal relevance of the dominant conceptual model.

Using Wind Driven Tumbleweed Rovers to Explore Martian Gully Features

NASA Technical Reports Server (NTRS)

Antol, Jeffrey; Woodard, Stanley E.; Hajos, Gregory A.; Heldmann, Jennifer L.; Taylor, Bryant D.

2004-01-01

Gully features have been observed on the slopes of numerous Martian crater walls, valleys, pits, and graben. Several mechanisms for gully formation have been proposed, including: liquid water aquifers (shallow and deep), melting ground ice, snow melt, CO2 aquifers, and dry debris flow. Remote sensing observations indicate that the most likely erosional agent is liquid water. Debate concerns the source of this water. Observations favor a liquid water aquifer as the primary candidate. The current strategy in the search for life on Mars is to "follow the water." A new vehicle known as a Tumbleweed rover may be able to conduct in-situ investigations in the gullies, which are currently inaccessible by conventional rovers. Deriving mobility through use of the surface winds on Mars, Tumbleweed rovers would be lightweight and relatively inexpensive thus allowing multiple rovers to be deployed in a single mission to survey areas for future exploration. NASA Langley Research Center (LaRC) is developing deployable structure Tumbleweed concepts. An extremely lightweight measurement acquisition system and sensors are proposed for the Tumbleweed rover that greatly increases the number of measurements performed while having negligible mass increase. The key to this method is the use of magnetic field response sensors designed as passive inductor-capacitor circuits that produce magnetic field responses whose attributes correspond to values of physical properties for which the sensors measure. The sensors do not need a physical connection to a power source or to data acquisition equipment resulting in additional weight reduction. Many of the sensors and interrogating antennae can be directly placed on the Tumbleweed using film deposition methods such as photolithography thus providing further weight reduction. Concepts are presented herein for methods to measure subsurface water, subsurface metals, planetary winds and environmental gases.

Using Wind Driven Tumbleweed Rovers to Explore Martian Gully Features

NASA Technical Reports Server (NTRS)

Antol, Jeffrey; Woodard, Stanley E.; Hajos, Gregory A.; Heldmann, Jennifer L.; Taylor, Bryant D.

2005-01-01

Gully features have been observed on the slopes of numerous Martian crater walls, valleys, pits, and graben. Several mechanisms for gully formation have been proposed, including: liquid water aquifers (shallow and deep), melting ground ice, snow melt, CO2 aquifers, and dry debris flow. Remote sensing observations indicate that the most likely erosional agent is liquid water. Debate concerns the source of this water. Observations favor a liquid water aquifer as the primary candidate. The current strategy in the search for life on Mars is to "follow the water." A new vehicle known as a Tumbleweed rover may be able to conduct in-situ investigations in the gullies, which are currently inaccessible by conventional rovers. Deriving mobility through use of the surface winds on Mars, Tumbleweed rovers would be lightweight and relatively inexpensive thus allowing multiple rovers to be deployed in a single mission to survey areas for future exploration. NASA Langley Research Center (LaRC) is developing deployable structure Tumbleweed concepts. An extremely lightweight measurement acquisition system and sensors are proposed for the Tumbleweed rover that greatly increases the number of measurements performed while having negligible mass increase. The key to this method is the use of magnetic field response sensors designed as passive inductor-capacitor circuits that produce magnetic field responses whose attributes correspond to values of physical properties for which the sensors measure. The sensors do not need a physical connection to a power source or to data acquisition equipment resulting in additional weight reduction. Many of the sensors and interrogating antennae can be directly placed on the Tumbleweed using film deposition methods such as photolithography thus providing further weight reduction. Concepts are presented herein for methods to measure subsurface water, subsurface metals, planetary winds and environmental gases.

Mars' Magnetic Atmosphere: Ionospheric Currents, Lightning (or Not), E and M Subsurface Sounding, and Future Missions

NASA Technical Reports Server (NTRS)

Espley, J. R.; Connerney, J. E. P.

2014-01-01

Mars' ionosphere has no obvious magnetic signs of large-scale, dustproduced lightning. However, there are numerous interesting ionospheric currents (some associated with crustal magnetic fields) which would allow for E&M subsurface sounding.

PREDICTING SUBSURFACE CONTAMINANT TRANSPORT AND TRANSFORMATION: CONSIDERATIONS FOR MODEL SELECTION AND FIELD VALIDATION

EPA Science Inventory

Predicting subsurface contaminant transport and transformation requires mathematical models based on a variety of physical, chemical, and biological processes. The mathematical model is an attempt to quantitatively describe observed processes in order to permit systematic forecas...

Characterization of the Subsurface Using Vp, Vs, Vp/Vs, and Poisson's Ratio from Body and Surface Waves

NASA Astrophysics Data System (ADS)

Catchings, R.

2017-12-01

P- and S-wave propagation differ in varying materials in the Earth's crust. As a result, combined measurements of P- and S-wave data can be used to infer properties of the shallow crust, including bulk composition, fluid saturation, faulting and fracturing, seismic velocities, reflectivity, and general structures. Ratios of P- to S-wave velocities and Poisson's ratio, which can be derived from the P- and S-wave data, can be particularly diagnostic of subsurface materials and their physical state. In field studies, S-wave data can be obtained directly with S-wave sources or from surface waves associated with P-wave sources. P- and S-wave data can be processed using reflection, refraction, and surface-wave-analysis methods. With the combined data, unconsolidated sediments, consolidated sediments, and rocks can be differentiated on the basis of seismic velocities and their ratios, as can saturated versus unsaturated sediments. We summarize studies where we have used combined P- and S-wave measurements to reliably map the top of ground water, prospect for minerals, locate subsurface faults, locate basement interfaces, determine basin shapes, and measure shear-wave velocities (with calculated Vs30), and other features of the crust that are important for hazards, engineering, and exploration purposes. When compared directly, we find that body waves provide more accurate measures than surface waves.

Assessment of DInSAR Potential in Simulating Geological Subsurface Structure

NASA Astrophysics Data System (ADS)

Fouladi Moghaddam, N.; Rudiger, C.; Samsonov, S. V.; Hall, M.; Walker, J. P.; Camporese, M.

2013-12-01

High resolution geophysical surveys, including seismic, gravity, magnetic, etc., provide valuable information about subsurface structuring but they are very costly and time consuming with non-unique and sometimes conflicting interpretations. Several recent studies have examined the application of DInSAR to estimate surface deformation, monitor possible fault reactivation and constrain reservoir dynamic behaviour in geothermal and groundwater fields. The main focus of these studies was to generate an elevation map, which represents the reservoir extraction induced deformation. This research study, however, will focus on developing methods to simulate subsurface structuring and identify hidden faults/hydraulic barriers using DInSAR surface observations, as an innovative and cost-effective reconnaissance exploration tool for planning of seismic acquisition surveys in geothermal and Carbon Capture and Sequestration regions. By direct integration of various DInSAR datasets with overlapping temporal and spatial coverage we produce multi-temporal ground deformation maps with high resolution and precision to evaluate the potential of a new multidimensional MSBAS technique (Samsonov & d'Oreye, 2012). The technique is based on the Small Baseline Subset Algorithm (SBAS) that is modified to account for variation in sensor parameters. It allows integration of data from sensors with different wave-band, azimuth and incidence angles, different spatial and temporal sampling and resolutions. These deformation maps then will be used as an input for inverse modelling to simulate strain history and shallow depth structure. To achieve the main objective of our research, i.e. developing a method for coupled InSAR and geophysical observations and better understanding of subsurface structuring, comparing DInSAR inverse modelling results with previously provided static structural model will result in iteratively modified DInSAR structural model for adequate match with in situ observations. The newly developed and modified algorithm will then be applied in another part of the region where subsurface information is limited.

Recent experimental data may point to a greater role for osmotic pressures in the subsurface

USGS Publications Warehouse

Neuzil, C.E.; Provost, A.M.

2009-01-01

Uncertainty about the origin of anomalous fluid pressures in certain geologic settings has caused researchers to take a second look at osmosis, or flow driven by chemical potential differences, as a pressure‐generating process in the subsurface. Interest in geological osmosis has also increased because of an in situ experiment by Neuzil (2000) suggesting that Pierre Shale could generate large osmotic pressures when highly compacted. In the last few years, additional laboratory and in situ experiments have greatly increased the number of data on osmotic properties of argillaceous formations, but they have not been systematically examined. In this paper we compile these data and explore their implications for osmotic pressure generation in subsurface systems. Rather than base our analysis on osmotic efficiencies, which depend strongly on concentration, we calculated values of a quantity we term osmotic specific surface area (Aso) that, in principle, is a property of the porous medium only. The Aso values are consistent with a surprisingly broad spectrum of osmotic behavior in argillaceous formations, and all the formations tested exhibited at least a modest ability to generate osmotic pressure. It appears possible that under appropriate conditions some formations can be highly effective osmotic membranes able to generate osmotic pressures exceeding 30 MPa (3 km of head) at porosities as high as ∼0.1 and pressures exceeding 10 MPa at porosities as high as ∼0.2. These findings are difficult to reconcile with the lack of compelling field evidence for osmotic pressures, and we propose three explanations for the disparity: (1) Our analysis is flawed and argillaceous formations are less effective osmotic membranes than it suggests; (2) the necessary subsurface conditions, significant salinity differences within intact argillaceous formations, are rare; or (3) osmotic pressures are unlikely to be detected and are not recognized when encountered. The last possibility, that osmotic pressures routinely escape detection or are attributed to other mechanisms, has important implications for understanding subsurface flow regimes.

[Microbes on the edge of global biosphere].

PubMed

Naganuma, T

2000-12-01

The search for life on the edge of global biosphere is a frontier to bridge conventional bio/ecology and exo/astrobiology. This communication reviews the foci of microbiological studies on the inhabitants of the selected "edges", i.e., deep-sea, deep subsurface and Antarctic habitats. The deep-sea is characterized as the no-light (non-photosynthetic) habitat, and the primary production is mostly due to the chemosynthetic autotrophy at the hydrothermal vents and methane-rich seeps. Formation of the chemosynthesis-dependent animal communities in the deep leads to the idea that such communities may be found in "ocean" of the Jovian satellite, Europa. The oxygen minimal layer (OML) in mid-water provides another field of deep-sea research. Modern OML is a relatively thin layer, found between the water depth of 200 and 1000 m, but was much thicker during the periods of oceanic anoxia events (OAEs) in the past. The history of oceanic biosphere is regarded as the cycle of OAE and non-OAE periods, and the remnants of the past OAEs may be seen in the modem OML. Anoxic (no-O2) condition is also characteristic of deep subsurface biosphere. Microorganisms in deep subsurface biosphere exploit every available oxidant, or terminal electron acceptor (TEA), for anaerobic respiration. Sulfate, nitrate, iron (III) and CO2 are the representative TEAs in the deep subsurface. Subsurface of hydrothermal vents, or sub-vent biosphere, may house brine (high salt) habitats and halophilic microorganisms. Some sub-vent halophiles were phylogenetically closely similar to the ones found in the Antarctic habitats which are extremely dry by the liophilizing climate. Below the 3000-4000 m-thick glacier on Antarctica, there have been >70 lakes with liquid water located. One of such sub-glacial lakes, Lake Vostok, has been a target of "life in extreme environments" and is about to be drill-penetrated for microbiological studies. These 'microbiological platforms' will provide new knowledge about the diversity and potential of the Earth's life and facilitate the capability of astrobiologial exploration.

Characterization of deep geothermal energy resources using Electro-Magnetic methods, Belgium

NASA Astrophysics Data System (ADS)

Loveless, Sian; Harcout-Menou, Virginie; De Ridder, Fjo; Claessens, Bert; Laenen, Ben

2014-05-01

Sedimentary basins in Northwest Europe have significant potential for low to medium enthalpy, deep geothermal energy resources. These resources are currently assessed using standard exploration techniques (seismic investigations followed by drilling of a borehole). This has enabled identification of geothermal resources but such techniques are extremely costly. The high cost of exploration remains one of the main barriers to geothermal project development due to the lack of capital in the geothermal industry. We will test the possibility of using the Electro-Magnetic (EM) methods to aid identification of geothermal resources in conjunction with more traditional exploration methods. An EM campaign could cost a third of a seismic campaign and is also often a passive technology, resulting in smaller environmental impacts than seismic surveys or drilling. EM methods image changes in the resistivity of the earth's sub-surface using natural or induced frequency dependant variations of electric and magnetic fields. Changes in resistivity can be interpreted as representing different subsurface properties including changes in rock type, chemistry, temperature and/or hydraulic transmissivity. While EM techniques have proven to be useful in geothermal exploration in high enthalpy areas in the last 2-3 years only a handful of studies assess their applicability in low enthalpy sedimentary basins. Challenges include identifying which sub-surface features cause changes in electrical resistivity as low enthalpy reservoirs are unlikely to exhibit the hydrothermally altered clay layer above the geothermal aquifer that is typical for high enthalpy reservoirs. Yet a principal challenge is likely to be the high levels of industrialisation in the areas of interest. Infrastructure such as train tracks and power cables can create a high level of background noise that can obfuscate the relevant signal. We present our plans for an EM campaign in the Flemish region of Belgium. Field techniques will be developed to increase the signal-noise ratio and identify background noise. Firstly, surface noise will be filtered off by non-parametric approaches such as proper orthogonal decomposition. Secondly, the EM signal and newly acquired seismic data will be combined to obtain a multi-dimensional earth model via an inversion process. Typically, these identification procedures are non-unique, resulting in multiple possible scenarios that cannot be distinguished based on the information at hand. To this end standard approaches) use a regularisation term including an apriori model. Here, Bayesian approaches will also be used, in which expert knowledge is used to guide the outcome to reasonable solutions. We will assess the reduction in uncertainty and therefore risks that EM methods can provide when used in combination with seismic surveys for geothermal exploration prior to drilling. It may also be possible to use this technique for monitoring the evolution of geothermal systems. Such techniques may prove to be extremely valuable for the future development of geothermal energy resources.

Characterization of seismic properties across scales: from the laboratory- to the field scale

NASA Astrophysics Data System (ADS)

Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

2016-04-01

When exploring geothermal systems, the main interest is on factors controlling the efficiency of the heat exchanger. This includes the energy state of the pore fluids and the presence of permeable structures building part of the fluid transport system. Seismic methods are amongst the most common exploration techniques to image the deep subsurface in order to evaluate such a geothermal heat exchanger. They make use of the fact that a seismic wave caries information on the properties of the rocks in the subsurface through which it passes. This enables the derivation of the stiffness and the density of the host rock from the seismic velocities. Moreover, it is well-known that the seismic waveforms are modulated while propagating trough the subsurface by visco-elastic effects due to wave induced fluid flow, hence, delivering information about the fluids in the rock's pore space. To constrain the interpretation of seismic data, that is, to link seismic properties with the fluid state and host rock permeability, it is common practice to measure the rock properties of small rock specimens in the laboratory under in-situ conditions. However, in magmatic geothermal systems or in systems situated in the crystalline basement, the host rock is often highly impermeable and fluid transport predominately takes place in fracture networks, consisting of fractures larger than the rock samples investigated in the laboratory. Therefore, laboratory experiments only provide the properties of relatively intact rock and an up-scaling procedure is required to characterize the seismic properties of large rock volumes containing fractures and fracture networks and to study the effects of fluids in such fractured rock. We present a technique to parameterize fractured rock volumes as typically encountered in Icelandic magmatic geothermal systems, by combining laboratory experiments with effective medium calculations. The resulting models can be used to calculate the frequency-dependent bulk modulus K(ω) and shear modulus G(ω), from which the P- and S-wave velocities V P(ω) and V S(ω) and the quality factors QP(ω) and QS(ω) of fluid saturated fractured rock volumes can be estimated. These volumes are much larger and contain more complex structures than the rock samples investigated in the laboratory. Thus, the derived quantities describe the elastic and anelastic (energy loss due to wave induced fluid flow) short-term deformation induced by seismic waves at scales that are relevant for field-scale seismic exploration projects.

A design study for a medium-scale field demonstration of the viscous barrier technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moridis, G.; Yen, P.; Persoff, P.

1996-09-01

This report is the design study for a medium-scale field demonstration of Lawrence Berkeley National Laboratory`s new subsurface containment technology for waste isolation using a new generation of barrier liquids. The test site is located in central California in a quarry owned by the Los Banos Gravel Company in Los Banos, California, in heterogeneous unsaturated deposits of sand, silt, and -ravel typical of many of the and DOE cleanup sites and particularly analogous to the Hanford site. The coals of the field demonstration are (a) to demonstrate the ability to create a continuous subsurface barrier isolating a medium-scale volume (30more » ft long by 30 ft wide by 20 ft deep, i.e. 1/10th to 1/8th the size of a buried tank at the Hanford Reservation) in the subsurface, and (b) to demonstrate the continuity, performance, and integrity of the barrier.« less

Influence of Assimilation of Subsurface Temperature Measurements on Simulations of Equatorial Undercurrent and South Equatorial Current Along the Pacific Equator

NASA Technical Reports Server (NTRS)

Halpern, David; Leetmaan, Ants; Reynolds, Richard W.; Ji, Ming

1997-01-01

Equatorial Pacific current and temperature fields were simulated with and without assimilation of subsurface temperature measurements for April 1992 - March 1995, and compared with moored bouy and research vessel current measurements.

GIS prospectivity mapping and 3D modeling validation for potential uranium deposit targets in Shangnan district, China

NASA Astrophysics Data System (ADS)

Xie, Jiayu; Wang, Gongwen; Sha, Yazhou; Liu, Jiajun; Wen, Botao; Nie, Ming; Zhang, Shuai

2017-04-01

Integrating multi-source geoscience information (such as geology, geophysics, geochemistry, and remote sensing) using GIS mapping is one of the key topics and frontiers in quantitative geosciences for mineral exploration. GIS prospective mapping and three-dimensional (3D) modeling can be used not only to extract exploration criteria and delineate metallogenetic targets but also to provide important information for the quantitative assessment of mineral resources. This paper uses the Shangnan district of Shaanxi province (China) as a case study area. GIS mapping and potential granite-hydrothermal uranium targeting were conducted in the study area combining weights of evidence (WofE) and concentration-area (C-A) fractal methods with multi-source geoscience information. 3D deposit-scale modeling using GOCAD software was performed to validate the shapes and features of the potential targets at the subsurface. The research results show that: (1) the known deposits have potential zones at depth, and the 3D geological models can delineate surface or subsurface ore-forming features, which can be used to analyze the uncertainty of the shape and feature of prospectivity mapping at the subsurface; (2) single geochemistry anomalies or remote sensing anomalies at the surface require combining the depth exploration criteria of geophysics to identify potential targets; and (3) the single or sparse exploration criteria zone with few mineralization spots at the surface has high uncertainty in terms of the exploration target.

Time series analysis of contaminant transport in the subsurface: applications to conservative tracer and engineered nanomaterials.

PubMed

Bai, Chunmei; Li, Yusong

2014-08-01

Accurately predicting the transport of contaminants in the field is subject to multiple sources of uncertainty due to the variability of geological settings, the complexity of field measurements, and the scarcity of data. Such uncertainties can be amplified when modeling some emerging contaminants, such as engineered nanomaterials, when a fundamental understanding of their fate and transport is lacking. Typical field work includes collecting concentration at a certain location for an extended period of time, or measuring the movement of plume for an extended period time, which would result in a time series of observation data. This work presents an effort to evaluate the possibility of applying time series analysis, particularly, autoregressive integrated moving average (ARIMA) models, to forecast contaminant transport and distribution in the subsurface environment. ARIMA modeling was first assessed in terms of its capability to forecast tracer transport at two field sites, which had different levels of heterogeneity. After that, this study evaluated the applicability of ARIMA modeling to predict the transport of engineered nanomaterials at field sites, including field measured data of nanoscale zero valent iron and (nZVI) and numerically generated data for the transport of nano-fullerene aggregates (nC60). This proof-of-concept effort demonstrates the possibility of applying ARIMA to predict the contaminant transport in the subsurface environment. Like many other statistical models, ARIMA modeling is only descriptive and not explanatory. The limitation and the challenge associated with applying ARIMA modeling to contaminant transport in the subsurface are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Time series analysis of contaminant transport in the subsurface: Applications to conservative tracer and engineered nanomaterials

NASA Astrophysics Data System (ADS)

Bai, Chunmei; Li, Yusong

2014-08-01

Accurately predicting the transport of contaminants in the field is subject to multiple sources of uncertainty due to the variability of geological settings, the complexity of field measurements, and the scarcity of data. Such uncertainties can be amplified when modeling some emerging contaminants, such as engineered nanomaterials, when a fundamental understanding of their fate and transport is lacking. Typical field work includes collecting concentration at a certain location for an extended period of time, or measuring the movement of plume for an extended period time, which would result in a time series of observation data. This work presents an effort to evaluate the possibility of applying time series analysis, particularly, autoregressive integrated moving average (ARIMA) models, to forecast contaminant transport and distribution in the subsurface environment. ARIMA modeling was first assessed in terms of its capability to forecast tracer transport at two field sites, which had different levels of heterogeneity. After that, this study evaluated the applicability of ARIMA modeling to predict the transport of engineered nanomaterials at field sites, including field measured data of nanoscale zero valent iron and (nZVI) and numerically generated data for the transport of nano-fullerene aggregates (nC60). This proof-of-concept effort demonstrates the possibility of applying ARIMA to predict the contaminant transport in the subsurface environment. Like many other statistical models, ARIMA modeling is only descriptive and not explanatory. The limitation and the challenge associated with applying ARIMA modeling to contaminant transport in the subsurface are also discussed.

Use of Large-Scale Multi-Configuration EMI Measurements to Characterize Subsurface Structures of the Vadose Zone.

NASA Astrophysics Data System (ADS)

Huisman, J. A.; Brogi, C.; Pätzold, S.; Weihermueller, L.; von Hebel, C.; Van Der Kruk, J.; Vereecken, H.

2017-12-01

Subsurface structures of the vadose zone can play a key role in crop yield potential, especially during water stress periods. Geophysical techniques like electromagnetic induction EMI can provide information about dominant shallow subsurface features. However, previous studies with EMI have typically not reached beyond the field scale. We used high-resolution large-scale multi-configuration EMI measurements to characterize patterns of soil structural organization (layering and texture) and their impact on crop productivity at the km2 scale. We collected EMI data on an agricultural area of 1 km2 (102 ha) near Selhausen (NRW, Germany). The area consists of 51 agricultural fields cropped in rotation. Therefore, measurements were collected between April and December 2016, preferably within few days after the harvest. EMI data were automatically filtered, temperature corrected, and interpolated onto a common grid of 1 m resolution. Inspecting the ECa maps, we identified three main sub-areas with different subsurface heterogeneity. We also identified small-scale geomorphological structures as well as anthropogenic activities such as soil management and buried drainage networks. To identify areas with similar subsurface structures, we applied image classification techniques. We fused ECa maps obtained with different coil distances in a multiband image and applied supervised and unsupervised classification methodologies. Both showed good results in reconstructing observed patterns in plant productivity and the subsurface structures associated with them. However, the supervised methodology proved more efficient in classifying the whole study area. In a second step, we selected hundred locations within the study area and obtained a soil profile description with type, depth, and thickness of the soil horizons. Using this ground truth data it was possible to assign a typical soil profile to each of the main classes obtained from the classification. The proposed methodology was effective in producing a high resolution subsurface model in a large and complex study area that extends well beyond the field scale.

The HMI Magnetic Activity Index for Local-Area Helioseismology

NASA Astrophysics Data System (ADS)

Bogart, Richard S.; Baldner, Charles

2017-08-01

In order to provide context for the mapping of sub-surface flows and thermal structure by local helioseismic techniques and the study of their relation to local magnetic activity, a local Magnetic Activity Index (MAI) was introduced. The MAI provides an appropriate index value corresponding precisely to the extent in space and time of each region analyzed. It is intended to be a measure of the total magnetic flux in the region. Hemispheric averages of the MAI are very well correlated with independent global measures of solar magnetic activity. Improvements in the determination of the MAI from Helioseismic and Magnetic Imager (HMI) measurements have revealed statistical anomalies affecting a small but significant number of high-cadence (45-sec) magnetograms. We describe modifications to the MAI being explored, the identification and treatment of anomalous magnetic field values, and explore likely causes.

Using remote sensing techniques and field-based structural analysis to explore new gold and associated mineral sites around Al-Hajar mine, Asir terrane, Arabian Shield

NASA Astrophysics Data System (ADS)

Sonbul, Abdullah R.; El-Shafei, Mohamed K.; Bishta, Adel Z.

2016-05-01

Modern earth resource satellites provide huge amounts of digital imagery at different resolutions. These satellite imageries are considered one of the most significant sources of data for mineral exploration. Image processing techniques were applied to the exposed rocks around the Al-Aqiq area of the Asir terrane in the southern part of the Arabian Shield. The area under study has two sub-parallel N-S trending metamorphic belts of green-schist facies. The first belt is located southeast of Al-Aqiq, where the Al-Hajar Gold Mine is situated. It is essentially composed of metavolcanics and metasedimentary rocks, and it is intruded by different plutonic rocks of primarily diorite, syenite and porphyritic granite. The second belt is located northwest of Al-Aqiq, and it is composed of metavolcanics and metasedimentary rocks and is intruded by granite bodies. The current study aimed to distinguish the lithological units, detect and map the alteration zones, and extract the major fault lineaments around the Al-Hajar gold prospect. Digital satellite imageries, including Landsat 7 ETM + multispectral and panchromatic and SPOT-5 were used in addition to field verification. Areas with similar spectral signatures to the prospect were identified in the nearby metamorphic belt; it was considered as a target area and was inspected in the field. The relationships between the alteration zones, the mineral deposits and the structural elements were used to locate the ore-bearing zones in the subsurface. The metasedimentary units of the target area showed a dextral-ductile shearing top-to-the-north and the presence of dominant mineralized quartz vein-system. The area to the north of the Al-Hajar prospect showed also sub-parallel shear zones along which different types of alterations were detected. Field-based criteria such as hydrothermal breccia, jasper, iron gossans and porphyritic granite strongly indicate the presence of porphyry-type ore deposits in Al-Hajar metamorphic belt that may proof promising for subsurface mining.

[Distribution and enrichment characteristics of organic carbon and total nitrogen in mollisols under long-term fertilization].

PubMed

Xu, Xiang-ru; Luo, Kun; Zhou, Bao-ku; Wang, Jing-kuan; Zhang, Wen-ju; Xu, Ming-gang

2015-07-01

The characteristics and changes of soil organic carbon (SOC) and total nitrogen (TN) in different size particles of soil under different agricultural practices are the basis for better understanding soil carbon sequestration of mollisols. Based on a 31-year long-term field experiment located at the Heilongjiang Academy of Agricultural Sciences (Harbin) , soil samples under six treatments were separated by size-fractionation method to explore changes and distribution of SOC and TN in coarse sand, fine sand, silt and clay from the top layer (0-20 cm) and subsurface layer (20-40 cm). Results showed that long-term application of manure (M) increased the percentages of SOC and TN in coarse sand and clay size fractions. In the top layer, application of nitrogen, phosphorus and potassium fertilizers combined with manure (NPKM) increased the percentages of SOC and TN in coarse sand by 191.3% and 179.3% compared with the control (CK), whereas M application increased the percentages of SOC and TN in clay by 45% and 47% respectively. For subsurface layers, the increase rates of SOC and TN in corresponding parts were lower than that in top layer. In the surface and subsurface layers, the percentages of SOC storage in silt size fraction accounted for 42%-63% and 48%-54%, TN storage accounted for 34%-59% and 41%-47%, respectively. The enrichment factors of SOC and TN in coarse sand and clay fractions of surface layers increased significantly under the treatments with manure. The SOC and TN enrichment factors were highest in the NPKM, being 2.30 and 1.88, respectively, while that in the clay fraction changed little in the subsurface layer.

The Naiades: A Mars Scout Proposal for Electromagnetic and Seismic Groundwater Exploration

NASA Astrophysics Data System (ADS)

Grimm, R. E.

2002-12-01

Detection of subsurface, liquid water is an overarching objective of the Mars Exploration Program (MEP) because of its impacts on life, climate, geology, and preparation for human exploration. Although planned orbital radars seek to map subsurface water, methods with more robust depth-penetration, discrimination, and characterization capabilities are necessary to "ground truth" any results from such radars. Low-frequency electromagnetic (EM) methods exploit induction rather than wave propagation and are sensitive to electrical conductivity rather than dielectric constant. Groundwater on Mars will likely be saline and therefore will present a near-ideal EM target, especially beneath very dry overburden. The Naiades Mars Scout - named for the Greek mythological nymphs of springs, rivers, lakes, and fountains - comprise twin Landers directed to a high-priority region for groundwater investigation. Broadband measurements of natural EM fields will be used for passive magnetotelluric, wave-tilt, and geomagnetic-depth soundings. Active, time-domain electromagnetic (TDEM) soundings will supplement natural sources (lightning?) above ~1 Hz. The two Landers are positioned within several tens of kilometers of each other so that remote references can improve natural-source data quality; useful results can, however, be acquired by a single Lander. The expected depth of exploration of the TDEM is several hundred meters or more, sufficient to determine whether putative groundwater near "gullies" is still extant. Low-frequency natural signals from the solar wind, ionosphere, and possibly crustal magnetospheres will enable passive soundings to 10 km or greater, sufficient to detect and characterize deep, stable groundwater. Additional mission objectives include detection of ground ice, characterization of natural EM fields, measurement of electrical properties of the atmosphere, dust, soil, and interior, constraints on planetary heat flow (from the thickness of the cryosphere), measurement of crustal magnetism, characterization of seismicity, seismic imaging of the interior, and assessment of landing-site geomorphology. A short-period seismometer and a wide-angle camera complete the payload to achieve these objectives. The Naiades mission strongly resonates with the main "Follow the Water" theme of the MEP, but in ways that are not currently within the scope of the MEP or that of NASA's international partners. The combination of established terrestrial methods for groundwater exploration, robust flight systems, and cost effectiveness proposed for the Naiades is a relatively low-risk approach to answering key questions about water on Mars within the Scout framework.

Exploring the role of mixing between subsurface flow paths on transit time distributions using a Lagrangian model

NASA Astrophysics Data System (ADS)

Zehe, Erwin; Jackisch, Conrad; Rodriguez, Nicolas; Klaus, Julian

2017-04-01

Only a minute amount of global fresh water is stored in the unsaturated zone. Yet this tiny compartment controls soil microbial activity and associated trace gas emissions, transport and transformations of contaminants, plant productivity, runoff generation and groundwater recharge. To date, the processes controlling renewal and age of different fractions of the soil water stock are far from being understood. Current theories and process concepts were largely inferred either from over-simplified laboratory experiments, or non-exhaustive point observations and tracer data in the field. Tracer data provide key but yet integrated information about the distribution of travel times of the tracer molecules to a certain depth or on their travel depth distribution within a given time. We hence are able to observe the "effect" of soil structure i.e. partitioning of infiltrating water between fast preferential and slow flow paths and imperfect subsequent mixing between these flow paths in the subsurface and the related plant water uptake. However, we are not able to study the "cause" - because technologies for in-situ observations of flow, flow path topology and exchange processes at relevant interfaces have up to now not been at hand. In the present study we will make use of a Lagrangian model for subsurface water dynamics to explore how subsurface heterogeneity and mixing among different storage fractions affects residence time distribution in the unsaturated zone in a forward approach. Soil water is represented by particles of constant mass, which travel according to the Itô form of the Fokker Planck equation. The model concept builds on established soil physics by estimating the drift velocity and the diffusion term based on the soil water characteristics. The model has been shown to simulate capillary driven soil moisture dynamics in good accordance with a) the Richards equation and b) observed soil moisture data in different soil. The particle model may furthermore account for preferential non equilibrium infiltration in a straightforward manner by treating event water as different type of particle, which travel initially in a macropore/ coarse pore fraction and experience a slow diffusive mixing with the pre-event water particles within a characteristic mixing time. In the present study we will particularly use the last approach in combination with artificial tracer data and stable isotopes to explore how different assumptions on mixing between different flow paths affect the travel time and residence time distributions of water particles in different fractions of the pore space.

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

PubMed Central

Smits, Kathleen; Eagen, Victoria; Trautz, Andrew

2015-01-01

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study evaporation under various surface boundary conditions to improve our current understanding and characterization of this multiphase phenomenon as well as to validate numerical heat and mass transfer theories that couple Navier-Stokes flow in the atmosphere and Darcian flow in the porous media. Experimental data were collected using a unique soil tank apparatus interfaced with a small climate controlled wind tunnel. The experimental apparatus was instrumented with a suite of state of the art sensor technologies for the continuous and autonomous collection of soil moisture, soil thermal properties, soil and air temperature, relative humidity, and wind speed. This experimental apparatus can be used to generate data under well controlled boundary conditions, allowing for better control and gathering of accurate data at scales of interest not feasible in the field. Induced airflow at several distinct wind speeds over the soil surface resulted in unique behavior of heat and mass transfer during the different evaporative stages. PMID:26131928

Tillage impact on herbicide loss by surface runoff and lateral subsurface flow

USDA-ARS?s Scientific Manuscript database

There is worldwide interest in conservation tillage practices because they can reduce surface runoff, agrichemical, and sediment loss from farm fields. Since these practices typically increase infiltration, their use may increase subsurface transport of water-soluble contaminants. Thus, to assess lo...

A field evaluation of subsurface and surface runoff. II. Runoff processes

USGS Publications Warehouse

Pilgrim, D.H.; Huff, D.D.; Steele, T.D.

1978-01-01

Combined use of radioisotope tracer, flow rate, specific conductance and suspended-sediment measurements on a large field plot near Stanford, California, has provided more detailed information on surface and subsurface storm runoff processes than would be possible from any single approach used in isolation. Although the plot was surficially uniform, the runoff processes were shown to be grossly nonuniform, both spatially over the plot, and laterally and vertically within the soil. The three types of processes that have been suggested as sources of storm runoff (Horton-type surface runoff, saturated overland flow, and rapid subsurface throughflow) all occurred on the plot. The nonuniformity of the processes supports the partial- and variable-source area concepts. Subsurface storm runoff occurred in a saturated layer above the subsoil horizon, and short travel times resulted from flow through macropores rather than the soil matrix. Consideration of these observations would be necessary for physically realistic modeling of the storm runoff process. ?? 1978.

Massively parallel electrical conductivity imaging of the subsurface: Applications to hydrocarbon exploration

NASA Astrophysics Data System (ADS)

Newman, Gregory A.; Commer, Michael

2009-07-01

Three-dimensional (3D) geophysical imaging is now receiving considerable attention for electrical conductivity mapping of potential offshore oil and gas reservoirs. The imaging technology employs controlled source electromagnetic (CSEM) and magnetotelluric (MT) fields and treats geological media exhibiting transverse anisotropy. Moreover when combined with established seismic methods, direct imaging of reservoir fluids is possible. Because of the size of the 3D conductivity imaging problem, strategies are required exploiting computational parallelism and optimal meshing. The algorithm thus developed has been shown to scale to tens of thousands of processors. In one imaging experiment, 32,768 tasks/processors on the IBM Watson Research Blue Gene/L supercomputer were successfully utilized. Over a 24 hour period we were able to image a large scale field data set that previously required over four months of processing time on distributed clusters based on Intel or AMD processors utilizing 1024 tasks on an InfiniBand fabric. Electrical conductivity imaging using massively parallel computational resources produces results that cannot be obtained otherwise and are consistent with timeframes required for practical exploration problems.

The emergence of hydrogeophysics for improved understanding of subsurface processes over multiple scales

PubMed Central

Hubbard, Susan S.; Huisman, Johan A.; Revil, André; Robinson, David A.; Singha, Kamini; Slater, Lee D.

2015-01-01

Abstract Geophysics provides a multidimensional suite of investigative methods that are transforming our ability to see into the very fabric of the subsurface environment, and monitor the dynamics of its fluids and the biogeochemical reactions that occur within it. Here we document how geophysical methods have emerged as valuable tools for investigating shallow subsurface processes over the past two decades and offer a vision for future developments relevant to hydrology and also ecosystem science. The field of “hydrogeophysics” arose in the late 1990s, prompted, in part, by the wealth of studies on stochastic subsurface hydrology that argued for better field‐based investigative techniques. These new hydrogeophysical approaches benefited from the emergence of practical and robust data inversion techniques, in many cases with a view to quantify shallow subsurface heterogeneity and the associated dynamics of subsurface fluids. Furthermore, the need for quantitative characterization stimulated a wealth of new investigations into petrophysical relationships that link hydrologically relevant properties to measurable geophysical parameters. Development of time‐lapse approaches provided a new suite of tools for hydrological investigation, enhanced further with the realization that some geophysical properties may be sensitive to biogeochemical transformations in the subsurface environment, thus opening up the new field of “biogeophysics.” Early hydrogeophysical studies often concentrated on relatively small “plot‐scale” experiments. More recently, however, the translation to larger‐scale characterization has been the focus of a number of studies. Geophysical technologies continue to develop, driven, in part, by the increasing need to understand and quantify key processes controlling sustainable water resources and ecosystem services. PMID:26900183

Transducer Design Experiments for Ground-Penetrating Acoustic Systems

DTIC Science & Technology

1996-03-19

subsurface imaging experiments have utilized a source (Tx) and receiver (Rx) configuration in which signals produced by a transmitter at the soil surface...development in the field of acoustic subsurface imaging are as follows. First, a transmitter designed to minimize the emission of surface waves, while

Escherichia coli Transport from Surface-Applied Manure to Subsurface Drains through Artificial Biopores

USDA-ARS?s Scientific Manuscript database

Transport of pathogenic bacteria in soils primarily occurs through soil mesopores and macropores (e.g., biopores and cracks). Field research has demonstrated that biopores and subsurface drains can be hydraulically connected. This research was conducted to investigate the importance of surface conne...

Optimal Electromagnetic (EM) Geophysical Techniques to Map the Concentration of Subsurface Ice and Adsorbed Water on Mars and the Moon

NASA Astrophysics Data System (ADS)

Stillman, D. E.; Grimm, R. E.

2013-12-01

Water ice is ubiquitous in our Solar System and is a probable target for planetary exploration. Mapping the lateral and vertical concentration of subsurface ice from or near the surface could determine the origin of lunar and martian ice and quantify a much-needed resource for human exploration. Determining subsurface ice concentration on Earth is not trivial and has been attempted previously with electrical resistivity tomography (ERT), ground penetrating radar (GPR), airborne EM (AEM), and nuclear magnetic resonance (NMR). These EM geophysical techniques do not actually detect ice, but rather the absence of unfrozen water. This causes a non-unique interpretation of frozen and dry subsurface sediments. This works well in the arctic because most locations are not dry. However, for planetary exploration, liquid water is exceedingly rare and subsurface mapping must discriminate between an ice-rich and a dry subsurface. Luckily, nature has provided a unique electrical signature of ice: its dielectric relaxation. The dielectric relaxation of ice creates a temperature and frequency dependence of the electrical properties and varies the relative dielectric permittivity from ~3.1 at radar frequencies to >100 at low frequencies. On Mars, sediments smaller than silt size can hold enough adsorbed unfrozen water to complicate the measurement. This is because the presence of absorbed water also creates frequency-dependent electrical properties. The dielectric relaxation of adsorbed water and ice can be separated as they have different shapes and frequency ranges as long as a spectrum spanning the two relaxations is measured. The volume concentration of ice and adsorbed water is a function of the strength of their relaxations. Therefore, we suggest that capacitively-coupled dielectric spectroscopy (a.k.a. spectral induced polarization or complex resistivity) can detect the concentration of both ice and adsorbed water in the subsurface. To prove this concept we have collected dielectric spectroscopy at the Cold Regions Research and Engineering Laboratory (CRREL) permafrost tunnel in Fox, AK. We were able to detect the ice relaxation in the subsurface despite the considerable amount of subsurface unfrozen water due to the presence of montmorillonite clay and much warmer temperatures than Mars or permanently shadowed regions of the Moon. While dielectric spectroscopy can be used to determine ice and adsorbed water content it does not possess the high resolution mapping capability of a GPR. Moreover, GPR cannot detect subsurface ice content in ice-sediment mixtures as evidenced in the interpretation of the Medusae Fossae Formation. Orbital radar surveys show this unit has a low attenuation and a dielectric permittivity near 4. This allows the formation to be interpreted as ice-rich or a dry high-porosity volcanic tuff unit. Therefore, combining GPR and dielectric spectroscopy will enable high-resolution structural and volatile mapping of the subsurface. Furthermore, the addition of neutron spectroscopy would add total hydrogen abundance in the top meter. This could lead to the determination of how much hydrogen resides in ice, adsorbed water, and minerals.

The Calvin impact crater and its associated oil production, Cass County, Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milstein, R.L.

1996-01-01

The Calvin impact crater is an isolated, nearly circular subsurface structure of Late Ordovician age in southwestern Michigan. The crater is defined by 110 oil and gas test wells, has a diameter of 6.2 km, and consists of a central dome exhibiting 415 m of structural uplift, an annular depression, and an encircling anticlinal rim. Exploration and development of three Devonian oil fields associated wit this structure provide all available subsurface data. All oil production is from the Middle Devonian Traverse Limestone, with the exception of one well producing from the Middle Devonian Sylvania Sandstone. This study models the grossmore » morphology of the Calvin structure using multiple tools and compares the results to known impact craters. Combined results of reflection seismic, gravity, magnetic, and resistivity data, as well as organized relationships between stratigraphic displacement and structural diameters observed in complex impact craters, suggest the Calvin structure is morphologically similar to recognized complex impact craters in sedimentary targets. In addition, individual quartz grains recovered from the Calvin structure exhibit decorated shock lamellae, Boehm lamellae, rhombohederal cleavage, and radiating concussion fractures. Based on the available data, I conclude the Calvin structure is a buried complex impact crater and that the trapping and reservoir characteristics of the associated Calvin 20, Juno Lake, and Calvin 28 oil fields are resultant of the craters morphology.« less

The Calvin impact crater and its associated oil production, Cass County, Michigan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milstein, R.L.

1996-12-31

The Calvin impact crater is an isolated, nearly circular subsurface structure of Late Ordovician age in southwestern Michigan. The crater is defined by 110 oil and gas test wells, has a diameter of 6.2 km, and consists of a central dome exhibiting 415 m of structural uplift, an annular depression, and an encircling anticlinal rim. Exploration and development of three Devonian oil fields associated wit this structure provide all available subsurface data. All oil production is from the Middle Devonian Traverse Limestone, with the exception of one well producing from the Middle Devonian Sylvania Sandstone. This study models the grossmore » morphology of the Calvin structure using multiple tools and compares the results to known impact craters. Combined results of reflection seismic, gravity, magnetic, and resistivity data, as well as organized relationships between stratigraphic displacement and structural diameters observed in complex impact craters, suggest the Calvin structure is morphologically similar to recognized complex impact craters in sedimentary targets. In addition, individual quartz grains recovered from the Calvin structure exhibit decorated shock lamellae, Boehm lamellae, rhombohederal cleavage, and radiating concussion fractures. Based on the available data, I conclude the Calvin structure is a buried complex impact crater and that the trapping and reservoir characteristics of the associated Calvin 20, Juno Lake, and Calvin 28 oil fields are resultant of the craters morphology.« less

Blueprint for a coupled model of sedimentology, hydrology, and hydrogeology in streambeds

NASA Astrophysics Data System (ADS)

Partington, Daniel; Therrien, Rene; Simmons, Craig T.; Brunner, Philip

2017-06-01

The streambed constitutes the physical interface between the surface and the subsurface of a stream. Across all spatial scales, the physical properties of the streambed control surface water-groundwater interactions. Continuous alteration of streambed properties such as topography or hydraulic conductivity occurs through erosion and sedimentation processes. Recent studies from the fields of ecology, hydrogeology, and sedimentology provide field evidence that sedimentological processes themselves can be heavily influenced by surface water-groundwater interactions, giving rise to complex feedback mechanisms between sedimentology, hydrology, and hydrogeology. More explicitly, surface water-groundwater exchanges play a significant role in the deposition of fine sediments, which in turn modify the hydraulic properties of the streambed. We explore these feedback mechanisms and critically review the extent of current interaction between the different disciplines. We identify opportunities to improve current modeling practices. For example, hydrogeological models treat the streambed as a static rather than a dynamic entity, while sedimentological models do not account for critical catchment processes such as surface water-groundwater exchange. We propose a blueprint for a new modeling framework that bridges the conceptual gaps between sedimentology, hydrogeology, and hydrology. Specifically, this blueprint (1) fully integrates surface-subsurface flows with erosion, transport, and deposition of sediments and (2) accounts for the dynamic changes in surface elevation and hydraulic conductivity of the streambed. Finally, we discuss the opportunities for new research within the coupled framework.

Field Investigation and Modeling Development for Hydrological and Carbon Cycles in Southwest Karst Region of China

NASA Astrophysics Data System (ADS)

Hu, X. B.

2017-12-01

It is required to understanding water cycle and carbon cycle processes for water resource management and pollution prevention and global warming influence in southwest karst region of China. Lijiang river basin is selected as our study region. Interdisciplinary field and laboratory experiments with various technologies are conducted to characterize the karst aquifers in detail. Key processes in the karst water cycle and carbon cycle are determined. Based on the MODFLOW-CFP model, new watershed flow and carbon cycle models are developed coupled subsurface and surface water flow models. Our study focus on the karst springshed in Mao village, the mechanisms coupling carbon cycle and water cycle are explored. This study provides basic theory and simulation method for water resource management and groundwater pollution prevention in China karst region.

Anticorrelation between Surface and Subsurface Point Defects and the Impact on the Redox Chemistry of TiO2(110)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, Yeohoon; Du, Yingge; Garcia, Juan C.

2015-02-02

Using combination of STM, DFT and SIMS, we explored the interplay and relative impact of surface vs. subsurface defects on the surface chemistry of rutile TiO2. STM results show that surface O vacancies (VO’s) are virtually absent in the vicinity of positively-charged subsurface point-defects. This observation is consistent with DFT calculations of impact of subsurface defect proximity on VO formation energy. To monitor the influence of such lateral anticorrelation on surface redox chemistry, a test reaction of the dissociative adsorption of O2 is employed, which is observed to be suppressed around them. DFT results attribute this to a perceived absencemore » of the intrinsic (Ti) (and likely extrinsic) interstitials in the nearest subsurface layer beneath “inhibited” areas. We also postulate that the entire nearest subsurface region could be voided of any charged point-defects, whereas prevalent VO’s are largely responsible for mediation of the redox chemistry at reduced TiO2(110) surface.« less

Peeking Beneath the Caldera: Communicating Subsurface Knowledge of Newberry Volcano

NASA Astrophysics Data System (ADS)

Mark-Moser, M.; Rose, K.; Schultz, J.; Cameron, E.

2016-12-01

"Imaging the Subsurface: Enhanced Geothermal Systems and Exploring Beneath Newberry Volcano" is an interactive website that presents a three-dimensional subsurface model of Newberry Volcano developed at National Energy Technology Laboratory (NETL). Created using the Story Maps application by ArcGIS Online, this format's dynamic capabilities provide the user the opportunity for multimedia engagement with the datasets and information used to build the subsurface model. This website allows for an interactive experience that the user dictates, including interactive maps, instructive videos and video capture of the subsurface model, and linked information throughout the text. This Story Map offers a general background on the technology of enhanced geothermal systems and the geologic and development history of Newberry Volcano before presenting NETL's modeling efforts that support the installation of enhanced geothermal systems. The model is driven by multiple geologic and geophysical datasets to compare and contrast results which allow for the targeting of potential EGS sites and the reduction of subsurface uncertainty. This Story Map aims to communicate to a broad audience, and provides a platform to effectively introduce the model to researchers and stakeholders.

Remote sensing of subsurface water temperature by Raman scattering.

PubMed

Leonard, D A; Caputo, B; Hoge, F E

1979-06-01

The application of Raman scattering to remote sensing of subsurface water temperature and salinity is considered, and both theoretical and experimental aspects of the technique are discussed. Recent experimental field measurements obtained in coastal waters and on a trans-Atlantic/Mediterranean research cruise are correlated with theoretical expectations. It is concluded that the Raman technique for remote sensing of subsurface water temperature has been brought from theoretical and laboratory stages to the point where practical utilization can now be developed.

Sensitivity Analysis of the Agricultural Policy/Environmental eXtender (APEX) for Phosphorus Loads in Tile-Drained Landscapes.

PubMed

Ford, W; King, K; Williams, M; Williams, J; Fausey, N

2015-07-01

Numerical modeling is an economical and feasible approach for quantifying the effects of best management practices on dissolved reactive phosphorus (DRP) loadings from agricultural fields. However, tools that simulate both surface and subsurface DRP pathways are limited and have not been robustly evaluated in tile-drained landscapes. The objectives of this study were to test the ability of the Agricultural Policy/Environmental eXtender (APEX), a widely used field-scale model, to simulate surface and tile P loadings over management, hydrologic, biologic, tile, and soil gradients and to better understand the behavior of P delivery at the edge-of-field in tile-drained midwestern landscapes. To do this, a global, variance-based sensitivity analysis was performed, and model outputs were compared with measured P loads obtained from 14 surface and subsurface edge-of-field sites across central and northwestern Ohio. Results of the sensitivity analysis showed that response variables for DRP were highly sensitive to coupled interactions between presumed important parameters, suggesting nonlinearity of DRP delivery at the edge-of-field. Comparison of model results to edge-of-field data showcased the ability of APEX to simulate surface and subsurface runoff and the associated DRP loading at monthly to annual timescales; however, some high DRP concentrations and fluxes were not reflected in the model, suggesting the presence of preferential flow. Results from this study provide new insights into baseline tile DRP loadings that exceed thresholds for algal proliferation. Further, negative feedbacks between surface and subsurface DRP delivery suggest caution is needed when implementing DRP-based best management practices designed for a specific flow pathway. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Cost-Effective and High-Resolution Subsurface Characterization Using Hydraulic Tomography

DTIC Science & Technology

2017-08-28

implementation and compare costs associated with HT and conventional methods. TECHNOLOGY DESCRIPTION The HT concept is analogous to the Computerized...develop guidance for HT field implementation and compare costs associated with HT and conventional methods. 15. SUBJECT TERMS Subsurface...3  2.1  TECHNOLOGY DESCRIPTION

Effect of subsurface drainage on streamflow in an agricultural headwater watershed

USDA-ARS?s Scientific Manuscript database

Artificial drainage, also known as subsurface or tile drainage is paramount to sustaining crop production agriculture in the poorly-drained, humid regions of the world. Hydrologic assessments of individual plots and fields with tile drainage are becoming common; however, a major void exists in our u...

Yield response and economics of shallow subsurface drip irrigation systems

USDA-ARS?s Scientific Manuscript database

Field tests were conducted using shallow subsurface drip irrigation (S3DI) on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) in rotation to investigate yield potential and economic sustainability of this irrigation system technique over a six year period. Dri...

A Study for Anisotropic Wavefield Analysis with Elastic Layered Models

NASA Astrophysics Data System (ADS)

Yoneki, R.; Mikada, H.; Takekawa, J.

2015-12-01

Subsurface materials are generally anisotropic due to complicated geological conditions, for example, sedimentary materials, fractures reflecting various stress conditions in the past and present in the subsurface. There are many studies on seismic wave propagation in TI (transversely isotropic) and orthorhombic media (e.g., Thomsen, 1986; Alkhalifah, 2000; Bansal and Sen, 2008). In most of those studies, the magnitude of anisotropy is assumed to be weak. Therefore, it may be not appropriate to apply their theories directly to strongly anisotropic subsurface media in seismic exploration. It is necessary to understand the effects of the anisotropy on the behavior of seismic wave propagation in strongly anisotropic media in the seismic exploration. In this study, we investigate the influence of strong anisotropy on received seismic waveforms using three-dimensional numerical models, and verified capability of detecting subsurface anisotropy. Our numerical models contain an isotropic and an anisotropic (VTI, transversely isotropic media with vertical symmetry axis) layer, respectively, in the isotropic background subsurface. Since the difference between the two models is only the anisotropy in the vertical propagation velocity, we could look at the influence of anisotropy in the residual wavefield that is the difference in the observed wavefields of two models. We analyzed the orbital motions of the residual wavefield to see what kind of wave motions the waveforms show. We found that the residual waveforms generated by the anisotropic layer include the orbital motions of shear waves right after the first arrival, i.e., mode conversion from the compressional waves due to the anisotropy. The residual waveforms could be exploited to estimate both the order of anisotropy and the thickness of anisotropic layer in subsurface.

Applying geophysical surveys for studying subsurface geology of monogenetic volcanic fields: the example of La Garrotxa Volcanic Field (NE of Iberian Peninsula)

NASA Astrophysics Data System (ADS)

Bolós, Xavier; Barde-Cabusson, Stéphanie; Pedrazzi, Dario; Martí, Joan; Casas, Albert; Lovera, Raúl; Nadal-Sala, Daniel

2014-05-01

Improving knowledge of the shallowest part of the feeding system of monogenetic volcanoes and the relationship with the subsurface geology is an important task. We applied high-precision geophysical techniques that are self-potential and electrical resistivity tomography, for the exploration of the uppermost part of the substrate of La Garrotxa Volcanic Field, which is part of the European Cenozoic Rift System. Previous geophysical studies carried out in the same area at a less detailed scale were aimed at identifying deeper structures, and together constitute the basis to establish volcanic susceptibility in La Garrotxa. Self-potential study allowed identifying key areas where electrical resistivity tomography could be conducted. Dykes and faults associated with several monogenetic cones were identified through the generation of resistivity models. The combined results confirm that shallow tectonics controlling the distribution of the foci of eruptive activity in this volcanic zone mainly correspond to NNW-SSE and accessorily by NNE-SSW Neogene extensional fissures and faults and concretely show the associated magmatic intrusions. These studies show that previous alpine tectonic structures played no apparent role in controlling the loci of this volcanism. Furthermore, the results obtained show that the changes in eruption dynamics occurring at different vents located at relatively short distances in this volcanic area can be controlled by shallow stratigraphical, structural, and hydrogeological features underneath these monogenetic volcanoes. This study was partially funded by the Beca Ciutat d'Olot en Ciències Naturals and the European Commission (FT7 Theme: ENV.2011.1.3.3-1; Grant 282759: "VUELCO").

Robotic Recon for Human Exploration

NASA Technical Reports Server (NTRS)

Deans, Matthew; Fong, Terry; Ford, Ken; Heldmann, Jennifer; Helper, Mark; Hodges, Kip; Landis, Rob; Lee, Pascal; Schaber, Gerald; Schmitt, Harrison H.

2009-01-01

Robotic reconnaissance has the potential to significantly improve scientific and technical return from lunar surface exploration. In particular, robotic recon may increase crew productivity and reduce operational risk for exploration. However, additional research, development and field-testing is needed to mature robot and ground control systems, refine operational protocols, and specify detailed requirements. When the new lunar surface campaign begins around 2020, and before permanent outposts are established, humans will initially be on the Moon less than 10% of the time. During the 90% of time between crew visits, robots will be available to perform surface operations under ground control. Understanding how robotic systems can best address surface science needs, therefore, becomes a central issue Prior to surface missions, lunar orbiters (LRO, Kaguya, Chandrayyan-1, etc.) will map the Moon. These orbital missions will provide numerous types of maps: visible photography, topographic, mineralogical and geochemical distributions, etc. However, remote sensing data will not be of sufficient resolution, lighting, nor view angle, to fully optimize pre-human exploration planning, e.g., crew traverses for field geology and geophysics. Thus, it is important to acquire supplemental and complementary surface data. Robotic recon can obtain such data, using robot-mounted instruments to scout the surface and subsurface at resolutions and at viewpoints not achievable from orbit. This data can then be used to select locations for detailed field activity and prioritize targets to improve crew productivity. Surface data can also help identify and assess terrain hazards, and evaluate alternate routes to reduce operational risk. Robotic recon could be done months in advance, or be part of a continuing planning process during human missions.

Identification and Simulation of Subsurface Soil patterns using hidden Markov random fields and remote sensing and geophysical EMI data sets

NASA Astrophysics Data System (ADS)

Wang, Hui; Wellmann, Florian; Verweij, Elizabeth; von Hebel, Christian; van der Kruk, Jan

2017-04-01

Lateral and vertical spatial heterogeneity of subsurface properties such as soil texture and structure influences the available water and resource supply for crop growth. High-resolution mapping of subsurface structures using non-invasive geo-referenced geophysical measurements, like electromagnetic induction (EMI), enables a characterization of 3D soil structures, which have shown correlations to remote sensing information of the crop states. The benefit of EMI is that it can return 3D subsurface information, however the spatial dimensions are limited due to the labor intensive measurement procedure. Although active and passive sensors mounted on air- or space-borne platforms return 2D images, they have much larger spatial dimensions. Combining both approaches provides us with a potential pathway to extend the detailed 3D geophysical information to a larger area by using remote sensing information. In this study, we aim at extracting and providing insights into the spatial and statistical correlation of the geophysical and remote sensing observations of the soil/vegetation continuum system. To this end, two key points need to be addressed: 1) how to detect and recognize the geometric patterns (i.e., spatial heterogeneity) from multiple data sets, and 2) how to quantitatively describe the statistical correlation between remote sensing information and geophysical measurements. In the current study, the spatial domain is restricted to shallow depths up to 3 meters, and the geostatistical database contains normalized difference vegetation index (NDVI) derived from RapidEye satellite images and apparent electrical conductivities (ECa) measured from multi-receiver EMI sensors for nine depths of exploration ranging from 0-2.7 m. The integrated data sets are mapped into both the physical space (i.e. the spatial domain) and feature space (i.e. a two-dimensional space framed by the NDVI and the ECa data). Hidden Markov Random Fields (HMRF) are employed to model the underlying heterogeneities in spatial domain and finite Gaussian mixture models are adopted to quantitatively describe the statistical patterns in terms of center vectors and covariance matrices in feature space. A recently developed parallel stochastic clustering algorithm is adopted to implement the HMRF models and the Markov chain Monte Carlo based Bayesian inference. Certain spatial patterns such as buried paleo-river channels covered by shallow sediments are investigated as typical examples. The results indicate that the geometric patterns of the subsurface heterogeneity can be represented and quantitatively characterized by HMRF. Furthermore, the statistical patterns of the NDVI and the EMI data from the soil/vegetation-continuum system can be inferred and analyzed in a quantitative manner.

Homogenization of Electromagnetic and Seismic Wavefields for Joint Inverse Modeling

NASA Astrophysics Data System (ADS)

Newman, G. A.; Commer, M.; Petrov, P.; Um, E. S.

2011-12-01

A significant obstacle in developing a robust joint imaging technology exploiting seismic and electromagnetic (EM) wave fields is the resolution at which these different geophysical measurements sense the subsurface. Imaging of seismic reflection data is an order of magnitude finer in resolution and scale compared to images produced with EM data. A consistent joint image of the subsurface geophysical attributes (velocity, electrical conductivity) requires/demands the different geophysical data types be similar in their resolution of the subsurface. The superior resolution of seismic data results from the fact that the energy propagates as a wave, while propagation of EM energy is diffusive and attenuates with distance. On the other hand, the complexity of the seismic wave field can be a significant problem due to high reflectivity of the subsurface and the generation of multiple scattering events. While seismic wave fields have been very useful in mapping the subsurface for energy resources, too much scattering and too many reflections can lead to difficulties in imaging and interpreting seismic data. To overcome these obstacles a formulation for joint imaging of seismic and EM wave fields is introduced, where each data type is matched in resolution. In order to accomplish this, seismic data are first transformed into the Laplace-Fourier Domain, which changes the modeling of the seismic wave field from wave propagation to diffusion. Though high frequency information (reflectivity) is lost with this transformation, several benefits follow: (1) seismic and EM data can be easily matched in resolution, governed by the same physics of diffusion, (2) standard least squares inversion works well with diffusive type problems including both transformed seismic and EM, (3) joint imaging of seismic and EM data may produce better starting velocity models critical for successful reverse time migration or full waveform imaging of seismic data (non transformed) and (4) possibilities to image across multiple scale lengths, incorporating different types of geophysical data and attributes in the process. Important numerical details of 3D seismic wave field simulation in the Laplace-Fourier domain for both acoustic and elastic cases will also be discussed.

Resource Exploration Approaches on Mars Using Multidisciplinary Earth-based Techniques

NASA Astrophysics Data System (ADS)

Wyrick, D. Y.; Ferrill, D. A.; Morris, A. P.; Smart, K. J.

2005-12-01

Water is the most important Martian exploration target - key to finding evidence of past life and providing a crucial resource for future exploration. Water is thought to be present in vapor, liquid, and ice phases on Mars. Except for ice in polar regions, little direct evidence of current surface accumulation of water has been found. Existing research has addressed potential source areas, including meteoric water, glacial ice, and volcanic centers and areas of discharge such as large paleo-outflow channels. Missing from these analyses is characterization of migration pathways of water in the subsurface from sources to discharge areas, and the present distribution of water. It has been estimated that ~90% of the global inventory of water on Mars resides in the subsurface. Targeting potential subsurface accumulations has relied primarily on theoretical modeling and geomorphic analysis. While global scale thermal modeling and analysis of the stability of ground ice provide important constraints on potential locations of large deposits of ice or liquid water, these studies have not accounted for variations in stratigraphy and structure that may strongly influence local distribution. Depth to water or ice on Mars is thought to be controlled primarily by latitude and elevation. However, the distribution of outflow channels clearly indicates that structural, stratigraphic, and geomorphic features all play important roles in determining past and present distribution of water and ice on Mars as they do on Earth. Resource exploration and extraction is a multi-billion dollar industry on Earth that has developed into a highly sophisticated enterprise with constantly improving exploration technologies. Common to all successful exploration programs, whether for hydrocarbons or water, is detailed analysis and integration of all available geologic, geophysical and remotely sensed data. The primary issues for identification and characterization of water or hydrocarbon resource accumulations can be summarized by three factors: trap, reservoir and charge. This presentation focuses on a detailed characterization of the fundamental elements believed to control trap, reservoir, and charge with respect to the identification of locations for extractable resources on Mars, primarily water and ice, but also gas hydrates. This new approach to resource exploration will also provide guidance for future research and exploration activities, including movement of methane from the subsurface to the surface and potential habitat sites for past or current life on Mars.

A new high-resolution electromagnetic method for subsurface imaging

NASA Astrophysics Data System (ADS)

Feng, Wanjie

For most electromagnetic (EM) geophysical systems, the contamination of primary fields on secondary fields ultimately limits the capability of the controlled-source EM methods. Null coupling techniques were proposed to solve this problem. However, the small orientation errors in the null coupling systems greatly restrict the applications of these systems. Another problem encountered by most EM systems is the surface interference and geologic noise, which sometimes make the geophysical survey impossible to carry out. In order to solve these problems, the alternating target antenna coupling (ATAC) method was introduced, which greatly removed the influence of the primary field and reduced the surface interference. But this system has limitations on the maximum transmitter moment that can be used. The differential target antenna coupling (DTAC) method was proposed to allow much larger transmitter moments and at the same time maintain the advantages of the ATAC method. In this dissertation, first, the theoretical DTAC calculations were derived mathematically using Born and Wolf's complex magnetic vector. 1D layered and 2D blocked earth models were used to demonstrate that the DTAC method has no responses for 1D and 2D structures. Analytical studies of the plate model influenced by conductive and resistive backgrounds were presented to explain the physical phenomenology behind the DTAC method, which is the magnetic fields of the subsurface targets are required to be frequency dependent. Then, the advantages of the DTAC method, e.g., high-resolution, reducing the geologic noise and insensitive to surface interference, were analyzed using surface and subsurface numerical examples in the EMGIMA software. Next, the theoretical advantages, such as high resolution and insensitive to surface interference, were verified by designing and developing a low-power (moment of 50 Am 2) vertical-array DTAC system and testing it on controlled targets and scaled target coils. At last, a high-power (moment of about 6800 Am2) vertical-array DTAC system was designed, developed and tested on controlled buried targets and surface interference to illustrate that the DTAC system was insensitive to surface interference even with a high-power transmitter and having higher resolution by using the large-moment transmitter. From the theoretical and practical analysis and tests, several characteristics of the DTAC method were found: (1) The DTAC method can null out the effect of 1D layered and 2D structures, because magnetic fields are orientation independent which lead to no difference among the null vector directions. This characteristic allows for the measurements of smaller subsurface targets; (2) The DTAC method is insensitive to the orientation errors. It is a robust EM null coupling method. Even large orientation errors do not affect the measured target responses, when a reference frequency and one or more data frequencies are used; (3) The vertical-array DTAC method is effective in reducing the geologic noise and insensitive to the surface interference, e.g., fences, vehicles, power line and buildings; (4) The DTAC method is a high-resolution EM sounding method. It can distinguish the depth and orientation of subsurface targets; (5) The vertical-array DTAC method can be adapted to a variety of rapidly moving survey applications. The transmitter moment can be scaled for effective study of near-surface targets (civil engineering, water resource, and environmental restoration) as well as deep targets (mining and other natural-resource exploration).

Monitoring microbial growth and activity using spectral induced polarization and low-field nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Zhang, Chi; Keating, Kristina; Revil, Andre

2015-04-01

Microbes and microbial activities in the Earth's subsurface play a significant role in shaping subsurface environments and are involved in environmental applications such as remediation of contaminants in groundwater and oil fields biodegradation. Stimulated microbial growth in such applications could cause wide variety of changes of physical/chemical properties in the subsurface. It is critical to monitor and determine the fate and transportation of microorganisms in the subsurface during such applications. Recent geophysical studies demonstrate the potential of two innovative techniques, spectral induced polarization (SIP) and low-field nuclear magnetic resonance (NMR), for monitoring microbial growth and activities in porous media. The SIP measures complex dielectric properties of porous media at low frequencies of exciting electric field, and NMR studies the porous structure of geologic media and characterizes fluids subsurface. In this laboratory study, we examined both SIP and NMR responses from bacterial growth suspension as well as suspension mixed with silica sands. We focus on the direct contribution of microbes to the SIP and NMR signals in the absence of biofilm formation or biomineralization. We used Zymomonas mobilis and Shewanella oneidensis (MR-1) for SIP and NMR measurements, respectively. The SIP measurements were collected over the frequency range of 0.1 - 1 kHz on Z. mobilis growth suspension and suspension saturated sands at different cell densities. SIP data show two distinct peaks in imaginary conductivity spectra, and both imaginary and real conductivities increased as microbial density increased. NMR data were collected using both CPMG pulse sequence and D-T2 mapping to determine the T2-distribution and diffusion properties on S. oneidensis suspension, pellets (live and dead), and suspension mixed with silica sands. NMR data show a decrease in the T2-distribution in S. oneidensis suspension saturated sands as microbial density increase. A clear distinction in the T2-distribution and D-T2 plots between live and dead cell pellets was also observed. These results will provide a basis for understanding the effect of microbes within geologic media on SIP and low-field NMR measurements. This research suggests that both SIP and NMR have the potential to monitor microbial growth and activities in the subsurface and could provide spatiotemporal variations in bacterial abundance in porous media.

Imaging lateral groundwater flow in the shallow subsurface using stochastic temperature fields

NASA Astrophysics Data System (ADS)

Fairley, Jerry P.; Nicholson, Kirsten N.

2006-04-01

Although temperature has often been used as an indication of vertical groundwater movement, its usefulness for identifying horizontal fluid flow has been limited by the difficulty of obtaining sufficient data to draw defensible conclusions. Here we use stochastic simulation to develop a high-resolution image of fluid temperatures in the shallow subsurface at Borax Lake, Oregon. The temperature field inferred from the geostatistical simulations clearly shows geothermal fluids discharging from a group of fault-controlled hydrothermal springs, moving laterally through the subsurface, and mixing with shallow subsurface flow originating from nearby Borax Lake. This interpretation of the data is supported by independent geochemical and isotopic evidence, which show a simple mixing trend between Borax Lake water and discharge from the thermal springs. It is generally agreed that stochastic simulation can be a useful tool for extracting information from complex and/or noisy data and, although not appropriate in all situations, geostatistical analysis may provide good definition of flow paths in the shallow subsurface. Although stochastic imaging techniques are well known in problems involving transport of species, e.g. delineation of contaminant plumes from soil gas survey data, we are unaware of previous applications to the transport of thermal energy for the purpose of inferring shallow groundwater flow.

Modeling Phosphorus Losses through Surface Runoff and Subsurface Drainage Using ICECREAM.

PubMed

Qi, Hongkai; Qi, Zhiming; Zhang, T Q; Tan, C S; Sadhukhan, Debasis

2018-03-01

Modeling soil phosphorus (P) losses by surface and subsurface flow pathways is essential in developing successful strategies for P pollution control. We used the ICECREAM model to simultaneously simulate P losses in surface and subsurface flow, as well as to assess effectiveness of field practices in reducing P losses. Monitoring data from a mineral-P-fertilized clay loam field in southwestern Ontario, Canada, were used for calibration and validation. After careful adjustment of model parameters, ICECREAM was shown to satisfactorily simulate all major processes of surface and subsurface P losses. When the calibrated model was used to assess tillage and fertilizer management scenarios, results point to a 10% reduction in total P losses by shifting autumn tillage to spring, and a 25.4% reduction in total P losses by injecting fertilizer rather than broadcasting. Although the ICECREAM model was effective in simulating surface and subsurface P losses when thoroughly calibrated, further testing is needed to confirm these results with manure P application. As illustrated here, successful use of simulation models requires careful verification of model routines and comprehensive calibration to ensure that site-specific processes are accurately represented. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Regionalization of subsurface stormflow parameters of hydrologic models: Derivation from regional analysis of streamflow recession curves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Sheng; Li, Hongyi; Huang, Maoyi

2014-07-21

Subsurface stormflow is an important component of the rainfall–runoff response, especially in steep terrain. Its contribution to total runoff is, however, poorly represented in the current generation of land surface models. The lack of physical basis of these common parameterizations precludes a priori estimation of the stormflow (i.e. without calibration), which is a major drawback for prediction in ungauged basins, or for use in global land surface models. This paper is aimed at deriving regionalized parameterizations of the storage–discharge relationship relating to subsurface stormflow from a top–down empirical data analysis of streamflow recession curves extracted from 50 eastern United Statesmore » catchments. Detailed regression analyses were performed between parameters of the empirical storage–discharge relationships and the controlling climate, soil and topographic characteristics. The regression analyses performed on empirical recession curves at catchment scale indicated that the coefficient of the power-law form storage–discharge relationship is closely related to the catchment hydrologic characteristics, which is consistent with the hydraulic theory derived mainly at the hillslope scale. As for the exponent, besides the role of field scale soil hydraulic properties as suggested by hydraulic theory, it is found to be more strongly affected by climate (aridity) at the catchment scale. At a fundamental level these results point to the need for more detailed exploration of the co-dependence of soil, vegetation and topography with climate.« less

Quantitative subsurface analysis using frequency modulated thermal wave imaging

NASA Astrophysics Data System (ADS)

Subhani, S. K.; Suresh, B.; Ghali, V. S.

2018-01-01

Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

Exploring Liquid Water Beneath Glaciers and Permafrost in Antarctica Through Airborne Electromagnetic Surveys

NASA Astrophysics Data System (ADS)

Auken, E.; Tulaczyk, S. M.; Foley, N.; Dugan, H.; Schamper, C.; Peter, D.; Virginia, R. A.; Sørensen, K.

2015-12-01

Here, we demonstrate how high powered airborne electromagnetic resistivity is efficiently used to map 3D domains of unfrozen water below glaciers and permafrost in the cold regions of the Earth. Exploration in these parts of the world has typically been conducted using radar methods, either ground-based or from an airborne platform. Radar is an excellent method if the penetrated material has a low electrical conductivity, but in materials with higher conductivity, such as sediments with liquid water, the energy is attenuated . Such cases are efficiently explored with electromagnetic methods, which attenuate less quickly in conductive media and can therefore 'see through' conductors and return valuable information about their electrical properties. In 2011, we used a helicopter-borne, time-domain electromagnetic sensor to map resistivity in the subsurface across the McMurdo Dry Valleys (MDV). The MDV are a polar desert in coastal Antarctica where glaciers, permafrost, ice-covered lakes, and ephemeral summer streams coexist. In polar environments, this airborne electromagnetic system excels at finding subsurface liquid water, as water which remains liquid under cold conditions must be sufficiently saline, and therefore electrically conductive. In Taylor Valley, in the MDV, our data show extensive subsurface low resistivity layers beneath higher resistivity layers, which we interpret as cryoconcentrated hypersaline brines lying beneath glaciers and frozen permafrost. These brines appear to be contiguous with surface lakes, subglacial regions, and the Ross Sea, which could indicate a regional hydrogeologic system wherein solutes may be transported between surface reservoirs by ionic diffusion and subsurface flow. The system as of 2011 had a maximum exploration depth of about 300 m. However, newer and more powerful airborne systems can explore to a depth of 500 - 600 m and new ground based instruments will get to 1000 m. This is sufficient to penetrate to the base of almost all coastal Antarctic glaciers. The MDV, where conductive brines exist beneath resistive glacial ice and frozen permafrost, are especially well suited to exploration by airborne electromagnetic, but similarly suitable systems are likely to exist elsewhere in the cryosphere.

Exploring inner structure of Titan's dunes from Cassini Radar observations

NASA Astrophysics Data System (ADS)

Sharma, P.; Heggy, E.; Farr, T. G.

2013-12-01

Linear dunes discovered in the equatorial regions of Titan by the Cassini-Huygens mission are morphologically very similar to many terrestrial linear dune fields. These features have been compared with terrestrial longitudinal dune fields like the ones in Namib desert in western Africa. This comparison is based on the overall parallel orientation of Titan's dunes to the predominant wind direction on Titan, their superposition on other geomorphological features and the way they wrap around topographic obstacles. Studying the internal layering of dunes has strong implications in understanding the hypothesis for their origin and evolution. In Titan's case, although the morphology of the dunes has been studied from Cassini Synthetic Aperture Radar (SAR) images, it has not been possible to investigate their internal structure in detail as of yet. Since no radar sounding data is available for studying Titan's subsurface yet, we have developed another technique to examine the inner layering of the dunes. In this study, we utilize multiple complementary radar datasets, including radar imaging data for Titan's and Earth's dunes and Ground Penetrating Radar (GPR)/radar sounding data for terrestrial dunes. Based on dielectric mixing models, we suggest that the Cassini Ku-band microwaves should be able to penetrate up to ~ 3 m through Titan's dunes, indicating that the returned radar backscatter signal would include contributions from both surface and shallow subsurface echoes. This implies that the shallow subsurface properties can be retrieved from the observed radar backscatter (σ0). In our analysis, the variation of the radar backscatter as a function of dune height is used to provide an insight into the layering in Titan's dunes. We compare the variation of radar backscatter with elevation over individual dunes on Titan and analogous terrestrial dunes in three sites (Great Sand Sea, Siwa dunes and Qattaniya dunes) in the Egyptian Sahara. We observe a strong, positive correlation between the backscatter and elevation along dune profile for the larger, older dunes in the Great Sand Sea in south-western Egypt and Siwa dune field in north-western Egypt, as opposed to the weak negative correlation exhibited by the smaller, younger Qattaniya dunes in north-eastern Egypt. This result is reinforced by our GPR survey on a large dune in the Siwa dune field and a smaller dune in the Qattaniya dune field. Our GPR data suggest the internal structure of larger dunes to consist of greater number of layers/cross-strata than smaller ones in the first 8 meters of the subsurface, which corresponds to the radar penetration depth at (0.8-1.2) GHz. Dunes on Titan exhibit backscatter-height dependency similar to the smaller Qattaniya dunes. In particular, the Shangri-La and Belet dunes on Titan exhibit a significantly stronger, negative correlation for the backscatter-height dependency compared to the Fensal and Aztlan dunes, suggesting a difference in the internal layering, relative ages and formation history of these dunes on Titan.

Elastic Reverse Time Migration (RTM) From Surface Topography

NASA Astrophysics Data System (ADS)

Akram, Naveed; Chen, Xiaofei

2017-04-01

Seismic Migration is a promising data processing technique to construct subsurface images by projecting the recorded seismic data at surface back to their origins. There are numerous Migration methods. Among them, Reverse Time Migration (RTM) is considered a robust and standard imaging technology in present day exploration industry as well as in academic research field because of its superior performance compared to traditional migration methods. Although RTM is extensive computing and time consuming but it can efficiently handle the complex geology, highly dipping reflectors and strong lateral velocity variation all together. RTM takes data recorded at the surface as a boundary condition and propagates the data backwards in time until the imaging condition is met. It can use the same modeling algorithm that we use for forward modeling. The classical seismic exploration theory assumes flat surface which is almost impossible in practice for land data. So irregular surface topography has to be considered in simulation of seismic wave propagation, which is not always a straightforward undertaking. In this study, Curved grid finite difference method (CG-FDM) is adapted to model elastic seismic wave propagation to investigate the effect of surface topography on RTM results and explore its advantages and limitations with synthetic data experiments by using Foothill model with topography as the true model. We focus on elastic wave propagation rather than acoustic wave because earth actually behaves as an elastic body. Our results strongly emphasize on the fact that irregular surface topography must be considered for modeling of seismic wave propagation to get better subsurface images specially in mountainous scenario and suggest practitioners to properly handled the geometry of data acquired on irregular topographic surface in their imaging algorithms.

Elastic Reverse Time Migration (RTM) From Surface Topography

NASA Astrophysics Data System (ADS)

Naveed, A.; Chen, X.

2016-12-01

Seismic Migration is a promising data processing technique to construct subsurface images by projecting the recorded seismic data at surface back to their origins. There are numerous Migration methods. Among them, Reverse Time Migration (RTM) is considered a robust and standard imaging technology in present day exploration industry as well as in academic research field because of its superior performance compared to traditional migration methods. Although RTM is extensive computing and time consuming but it can efficiently handle the complex geology, highly dipping reflectors and strong lateral velocity variation all together. RTM takes data recorded at the surface as a boundary condition and propagates the data backwards in time until the imaging condition is met. It can use the same modeling algorithm that we use for forward modeling. The classical seismic exploration theory assumes flat surface which is almost impossible in practice for land data. So irregular surface topography has to be considered in simulation of seismic wave propagation, which is not always a straightforward undertaking. In this study, Curved grid finite difference method (CG-FDM) is adapted to model elastic seismic wave propagation to investigate the effect of surface topography on RTM results and explore its advantages and limitations with synthetic data experiments by using Foothill model with topography as the true model. We focus on elastic wave propagation rather than acoustic wave because earth actually behaves as an elastic body. Our results strongly emphasize on the fact that irregular surface topography must be considered for modeling of seismic wave propagation to get better subsurface images specially in mountainous scenario and suggest practitioners to properly handled the geometry of data acquired on irregular topographic surface in their imaging algorithms.

Strategic Planning for Exploration of the Martian Subsurface

NASA Technical Reports Server (NTRS)

Beaty, D. W.; Briggs, G.; Clifford, S. M.

2000-01-01

Exploration of the upper 2-5 km of the martian crust (i.e. the portion that we can realistically envision physically accessing) is a tantalizing prospect. This may provide our best opportunity to advance the three current objectives of the Mars exploration program: Life, Climate, and Resources, with a common theme of water.

Antibiotic resistance genes persist longer in soils with subsurface banded poultry litter

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the concentration of AR genes for sulfonamide (sulI), tetracycline (tetW), streptomycin (strpB) and for the class one integrase (intI1) gene in soils with subsurface banded PL. Field scale plots were established with triplicate treatments of either no fer...

SUBSURFACE CHARACTERIZATION AND MONITORING TECHNIQUES: A DESK REFERENCE GUIDE - VOLUME II: THE VADOSE ZONE, FIELD SCREENING AND ANALYTICAL METHODS - APPENDICES C AND D

EPA Science Inventory

Many EPA programs, including those under the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Response, Compensation, and Liability Act (CERCLA), require subsurface characterization and monitoring to detect ground-water contamination and provide data to deve...

Influence Of pH On The Transport Of Nanoscale Zinc Oxide In Saturated Porous Media

EPA Science Inventory

Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport mechanism of nZnO in such e...

Modeling Subsurface Behavior at the System Level: Considerations and a Path Forward

NASA Astrophysics Data System (ADS)

Geesey, G.

2005-12-01

The subsurface is an obscure but essential resource to life on Earth. It is an important region for carbon production and sequestration, a source and reservoir for energy, minerals and metals and potable water. There is a growing need to better understand subsurface possesses that control the exploitation and security of these resources. Our best models often fail to predict these processes at the field scale because of limited understanding of 1) the processes and the controlling parameters, 2) how processes are coupled at the field scale 3) geological heterogeneities that control hydrological, geochemical and microbiological processes at the field scale and 4) lack of data sets to calibrate and validate numerical models. There is a need for experimental data obtained at scales larger than those obtained at the laboratory bench that take into account the influence of hydrodynamics, geochemical reactions including complexation and chelation/adsorption/precipitation/ion exchange/oxidation-reduction/colloid formation and dissolution, and reactions of microbial origin. Furthermore, the coupling of each of these processes and reactions needs to be evaluated experimentally at a scale that produces data that can be used to calibrate numerical models so that they accurately describe field scale system behavior. Establishing the relevant experimental scale for collection of data from coupled processes remains a challenge and will likely be process-dependent and involve iterations of experimentation and data collection at different intermediate scales until the models calibrated with the appropriate date sets achieve an acceptable level of performance. Assuming that the geophysicists will soon develop technologies to define geological heterogeneities over a wide range of scales in the subsurface, geochemists need to continue to develop techniques to remotely measure abiotic reactions, while geomicrobiologists need to continue their development of complementary technologies to remotely measure microbial community parameters that define their key functions at a scale that accurately reflects their role in large scale subsurface system behavior. The practical questions that geomicrobiologist must answer in the short term are: 1) What is known about the activities of the dominant microbial populations or those of their closest relatives? 2) Which of these activities is likely to dominate under in situ conditions? In the process of answering these questions, researchers will obtain answers to questions of a more fundamental nature such as 1) How deep does "active" life extend below the surface of the seafloor and terrestrial subsurface? 2) How are electrons exchanged between microbial cells and solid phase minerals? 3) What is the metabolic state and mechanism of survival of "inactive" life forms in the subsurface? 4) What can genomes of life forms trapped in geological material tell us about evolution of life that current methods cannot? The subsurface environment represents a challenging environment to understand and model. As the need to understand subsurface processes increases and the technologies to characterize them become available, modeling subsurface behavior will approach the level of sophistication of models used today to predict behavior of other large scale systems such as the oceans.

Effect of Agricultural Practices on Hydrology and Water Chemistry in a Small Irrigated Catchment, Yakima River Basin, Washington

USGS Publications Warehouse

McCarthy, Kathleen A.; Johnson, Henry M.

2009-01-01

The role of irrigation and artificial drainage in the hydrologic cycle and the transport of solutes in a small agricultural catchment in central Washington's Yakima Valley were explored using hydrologic, chemical, isotopic, age-dating, and mineralogical data from several environmental compartments, including stream water, ground water, overland flow, and streambed pore water. A conceptual understanding of catchment hydrology and solute transport was developed and an inverse end-member mixing analysis was used to further explore the effects of agriculture in this small catchment. The median concentrations of major solutes and nitrates were similar for the single field site and for the catchment outflow site, indicating that the net effects of transport processes for these constituents were similar at both scales. However, concentrations of nutrients were different at the two sites, suggesting that field-scale variations in agricultural practices as well as nearstream and instream biochemical processes are important components of agricultural chemical transformation and transport in this catchment. This work indicates that irrigation coupled with artificial drainage networks may exacerbate the ecological effects of agricultural runoff by increasing direct connectivity between fields and streams and minimizing potentially mitigating effects (denitrification and dilution, for example) of longer subsurface pathways.

Implementing Monitored Natural Attenuation and Expediting Closure at Fuel-Release Sites

DTIC Science & Technology

2004-08-01

Center for Environmental Excellence AFCEE/ERS Air Force Center for Environmental Excellence/Science and Engineering Division AFRPA Air Force Real...auger, air - or mud- rotary , cable-tool) was and is dependent on the target drilling depths and the types of subsurface materials expected to be...95(2000) ASTM. 1995c. Guide for the use of direct air - rotary drilling for geoenvironmental exploration and installation of subsurface water quality

Sensitivity of transpiration to subsurface properties: Exploration with a 1-D model

NASA Astrophysics Data System (ADS)

Vrettas, Michail D.; Fung, Inez Y.

2017-06-01

The amount of moisture transpired by vegetation is critically tied to the moisture supply accessible to the root zone. In a Mediterranean climate, integrated evapotranspiration (ET) is typically greater in the dry summer when there is an uninterrupted period of high insolation. We present a 1-D model to explore the subsurface factors that may sustain ET through the dry season. The model includes a stochastic parameterization of hydraulic conductivity, root water uptake efficiency, and hydraulic redistribution by plant roots. Model experiments vary the precipitation, the magnitude and seasonality of ET demand, as well as rooting profiles and rooting depths of the vegetation. The results show that the amount of subsurface moisture remaining at the end of the wet winter is determined by the competition among abundant precipitation input, fast infiltration, and winter ET demand. The weathered bedrock retains ˜30% of the winter rain and provides a substantial moisture reservoir that may sustain ET of deep-rooted (>8 m) trees through the dry season. A small negative feedback exists in the root zone, where the depletion of moisture by ET decreases hydraulic conductivity and enhances the retention of moisture. Hence, hydraulic redistribution by plant roots is impactful in a dry season, or with a less conductive subsurface. Suggestions for implementing the model in the CESM are discussed.

Evaluation of the first simulation tool to quantitatively interpret the measurements of the ExoMars mission's Wisdom GPR

NASA Astrophysics Data System (ADS)

Dorizon, Sophie; Ciarletti, Valérie

2013-04-01

The Water Ice Sub-surface Deposits Observation on Mars (WISDOM) (500MHz - 3GHz) GPR is one of the instruments that have been selected as part of the Pasteur payload of ESA's 2018 ExoMars Rover mission. One of the main scientific objectives of the mission is to characterize the nature of the shallow sub-surface on Mars and WISDOM has been designed to explore the first 3 meters of the sub-surface with a vertical resolution of a few centimetres. Laboratory and field tests using the prototype developed for the ExoMars mission by LATMOS (Laboratoire Atmosphère, Milieux, Observations Spatiales) in collaboration with the AOB (Bordeaux) and the university of Dresden (Germany) are regularly performed to assess and improve the radar performances. In order to quantitatively interpret the experimental data obtained, we developed a simulation tool based on ray-tracing. This code proves to be a fast practical way even if simplified to help radargrams interpretation. The WISDOM GPR, unlike most traditional GPRs, is operated approximately 30 centimetres above the surface. This configuration implies that the propagation between the antenna and the surface cannot be neglected especially because the instrument's aim is to characterise the very shallow subsurface. As a consequence, while we can draw advantage of this specific configuration by using the surface echo's amplitude to retrieve information about the top layer's roughness and permittivity value, precise location of buried reflector becomes more complicated. Indeed, the signature distinctive of individual reflectors buried in the sub-surface is not more an exact mathematical hyperbola. When the individual reflector is buried deep enough in the subsurface, the adjustment by an hyperbolic function still allows the retrieval of the reflector's location and the permittivity value of the surrounding medium. But in case of a reflector closer to the surface, the approximation is no longer valid. We propose a robust model adjustment that can be used for any reflector's depth. The physical assumptions taken into account are presented. Finally, results for different configurations and the validation of the limit conditions for which this adjustment method is reliable are shown. Preliminary analyzes on real data show the good performance of the method developed. Other modelling techniques will be considered to complete a full data interpretation taking the best from the instrument capacities

Final technical report for project titled Quantitative Characterization of Cell Aggregation/Adhesion as Predictor for Distribution and Transport of Microorganisms in Subsurface Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, April Z.; Wan, Kai-tak

This project aims to explore and develop enabling methodology and techniques for nano-scale characterization of microbe cell surface contact mechanics, interactions and adhesion quantities that allow for identification and quantification of indicative properties related to microorganism migration and transport behavior in porous media and in subsurface environments. Microbe transport has wide impact and therefore is of great interest in various environmental applications such as in situ or enhanced subsurface bioremediation,filtration processes for water and wastewater treatments and protection of drinking water supplies. Although great progress has been made towards understanding the identities and activities of these microorganisms in the subsurface,more » to date, little is known of the mechanisms that govern the mobility and transport of microorganisms in DOE’s contaminated sites, making the outcomes of in situ natural attenuation or contaminant stability enhancement unpredictable. Conventionally, movement of microorganisms was believed to follows the rules governing solute (particle) transport. However, recent studies revealed that cell surface properties, especially those pertaining to cell attachment/adhesion and aggregation behavior, can cause the microbe behavior to deviate from non-viable particles and hence greatly influence the mobility and distribution of microorganisms in porous media.This complexity highlights the need to obtain detailed information of cell-cell and cell-surface interactions in order to improve and refine the conceptual and quantitative model development for fate and transport of microorganisms and contaminant in subsurface. Traditional cell surface characterization methods are not sufficient to fully predict the deposition rates and transport behaviors of microorganism observed. A breakthrough of methodology that would allow for quantitative and molecular-level description of intrinsic cell surface properties indicative for cell-surface interactions is essential for the field. To tackle this, we have developed a number of new Bio-nanomechanical techniques, including reflection interference contrast microscopy (RICM) and bio-AFM (Atomic Force Microscopy), for cell adhesion-detachment measurement of the long-range surface interactions, in combination with mathematical modeling, which would allow us to characterize the mechanical behavior from single cell to multi-cell aggregate, critical thresholds for large scale coaggregation and transportation of cells and aggregates in the presence of long range inter-surface forces etc. Although some technical and mathematical challenges remain, the preliminary results promise great breakthrough potential. In this study, we investigated the cellular surface characteristics of representative bio-remediating microorganisms relevant to DOE IFRC (Integrated Field-Scale Subsurface Research Challenges) sites and their transport behaviors in porous media, aiming to draw a groundbreaking correlation between the micro-scale genetic and biological origin-based cell surface properties, the consequent mechanical adhesion and aggregation behaviors, and the macro-scale microbial mobility and retention in porous media, which are unavailable in the literature. The long-term goal is to significantly improve the mechanistic and quantitative understanding of microbial mobility, sorption, and transport within reactive transport models as needed to manipulate subsurface contaminant fate and transport predictions.« less

Subsurface Microbes Expanding the Tree of Life

ScienceCinema

Banfield, Jillian

2018-02-14

Jillian Banfield, Ph.D., UC Berkeley Professor and Berkeley Lab Earth Sciences Division staff scientist and long-time user of the DOE Joint Genome Institute’s resources shares her perspective on how the DOE JGI helps advance her research addressing knowledge gaps related to the roles of subsurface microbial communities in biogeochemical cycling. The video was filmed near the town of Rifle, Colorado at the primary field site for Phase I of the Subsurface Systems Scientific Focus Area 2.0 sponsored by the DOE Office of Biological and Environmental Research.

Advancing Knowledge on Fugitive Natural Gas from Energy Resource Development at a Controlled Release Field Observatory

NASA Astrophysics Data System (ADS)

Cahill, A. G.; Chao, J.; Forde, O.; Prystupa, E.; Mayer, K. U.; Black, T. A.; Tannant, D. D.; Crowe, S.; Hallam, S.; Mayer, B.; Lauer, R. M.; van Geloven, C.; Welch, L. A.; Salas, C.; Levson, V.; Risk, D. A.; Beckie, R. D.

2017-12-01

Fugitive gas, comprised primarily of methane, can be unintentionally released from upstream oil and gas development either at surface from leaky infrastructure or in the subsurface through failure of energy well bore integrity. For the latter, defective cement seals around energy well casings may permit buoyant flow of natural gas from the deeper subsurface towards shallow aquifers, the ground surface and potentially into the atmosphere. Concerns associated with fugitive gas release at surface and in the subsurface include contributions to greenhouse gas emissions, subsurface migration leading to accumulation in nearby infrastructure and impacts to groundwater quality. Current knowledge of the extent of fugitive gas leakage including how to best detect and monitor over time, and particularly its migration and fate in the subsurface, is incomplete. We have established an experimental field observatory for evaluating fugitive gas leakage in an area of historic and ongoing hydrocarbon resource development within the Montney Resource Play of the Western Canadian Sedimentary Basin, British Columbia, Canada. Natural gas will be intentionally released at surface and up to 25 m below surface at various rates and durations. Resulting migration patterns and impacts will be evaluated through examination of the geology, hydrogeology, hydro-geochemistry, isotope geochemistry, hydro-geophysics, vadose zone and soil gas processes, microbiology, and atmospheric conditions. The use of unmanned aerial vehicles and remote sensors for monitoring and detection of methane will also be assessed for suitability as environmental monitoring tools. Here we outline the experimental design and describe initial research conducted to develop a detailed site conceptual model of the field observatory. Subsequently, results attained from pilot surface and sub-surface controlled natural gas releases conducted in late summer 2017 will be presented as well as results of numerical modelling conducted to plan methane release experiments in 2018 and onwards. This research will create knowledge which informs strategies to detect and monitor fugitive gas fluxes at the surface and in groundwater; as well as guide associated regulatory and technical policies.

Bistatic GPR Measurements in the Egyptian Western Desert - Measured and Simulated data

NASA Astrophysics Data System (ADS)

Ciarletti, V.; Le Gall, A.; Berthelier, J.; Ney, R.; Corbel, C.; Dolon, F.

2006-12-01

The TAPIR (Terrestrial And Planetary Investigation Radar) instrument has been designed at CETP (Centre d'etude des Environnements Terrestre et Planetaires) to explore the deep Martian subsurface (down to a few kilometers) and to detect liquid water reservoirs. TAPIR is an impulse ground penetrating radar operating at central frequencies ranging from 2 to 4 MHz operating from the surface. In November 2005, an updated version of the instrument working either in monostatic or in bi-static mode was tested in the Egyptian Western Desert. The work presented here focuses on the bi-static measurements performed on the Abou Saied plateau which shows a horizontally layered sub-surface. The electromagnetic signal was transmitted using one of the two orthogonal 70 m loaded electrical dipole antennas of the transmitting GPR. A second GPR, 50 or 100 meters apart, was dedicated to the signal reception. The received waves were characterized by a set of 5 measurements performed on the receiving GPR : the two horizontal components of the electric field and the three composants of the magnetic field. They were used to compute the direction of arrival of the incoming waves and to retrieve more accurately their propagation path and especially to discriminate between waves due to some sub-surface reflecting structure and those due to interaction with the surface clutter. A very efficient synchronization between the two radars enabled us to perform coherent additions up to 2^{31} which improves dramatically the obtained signal to noise ratio. Complementary electromagnetic measurements were conducted on the same site by the LPI (Lunar and Planetary Institute) and the SwRI (Southwest Research Institute). They provided independent information which helped the interpretation of the TAPIR data. Accurate simulations obtained by FDTD taking into account the information available are presented and used for both the interpretation of the measured data and the validation of the instrument.

Evaluation of a genome-scale in silico metabolic model for Geobacter metallireducens by using proteomic data from a field biostimulation experiment.

PubMed

Fang, Yilin; Wilkins, Michael J; Yabusaki, Steven B; Lipton, Mary S; Long, Philip E

2012-12-01

Accurately predicting the interactions between microbial metabolism and the physical subsurface environment is necessary to enhance subsurface energy development, soil and groundwater cleanup, and carbon management. This study was an initial attempt to confirm the metabolic functional roles within an in silico model using environmental proteomic data collected during field experiments. Shotgun global proteomics data collected during a subsurface biostimulation experiment were used to validate a genome-scale metabolic model of Geobacter metallireducens-specifically, the ability of the metabolic model to predict metal reduction, biomass yield, and growth rate under dynamic field conditions. The constraint-based in silico model of G. metallireducens relates an annotated genome sequence to the physiological functions with 697 reactions controlled by 747 enzyme-coding genes. Proteomic analysis showed that 180 of the 637 G. metallireducens proteins detected during the 2008 experiment were associated with specific metabolic reactions in the in silico model. When the field-calibrated Fe(III) terminal electron acceptor process reaction in a reactive transport model for the field experiments was replaced with the genome-scale model, the model predicted that the largest metabolic fluxes through the in silico model reactions generally correspond to the highest abundances of proteins that catalyze those reactions. Central metabolism predicted by the model agrees well with protein abundance profiles inferred from proteomic analysis. Model discrepancies with the proteomic data, such as the relatively low abundances of proteins associated with amino acid transport and metabolism, revealed pathways or flux constraints in the in silico model that could be updated to more accurately predict metabolic processes that occur in the subsurface environment.

Giddings Edwards (Cretaceous) field, south Texas: carbonate channel or elongate buildup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lomando, A.J.; Mazzullo, S.J.

1989-03-01

Giddings Edwards field, located in Fayette County, Texas, is situated on the broad Cretaceous (Albian) shallow shelf, approximately 20 mi north of the main Edwards shelf-margin reef trend. The Giddings field produces gas from an elongate stratigraphic trap approximately 9.5 mi long and 1.8 mi wide, encased in argillaceous lime mudstones and shales; the field is oriented normal to the contiguous Edwards reef trend. Available cores and cuttings samples from the central portion of the field indicate that the field reservoir is composed of biopackstones and grainstones interpreted to have been deposited in a high-energy shelf environment. The facies systemmore » is characterized by stacked reservoirs having a maximum gross pay thickness of over 100 ft, containing primary interparticle and secondary biomoldic porosity, both of which have been modified slightly by chemical compaction and partial occlusion by sparry calcite and saddle dolomite cements. Despite reasonable subsurface sample and mechanical log control within and surrounding the field, its depositional origin remains equivocal. Such uncertainty has important bearing on predictive models for the exploration for additional Edwards shelfal hydrocarbon reservoirs. The elongate, biconvex geometry of the productive carbonate sands, their northward thinning, and apparent updip bifurcation suggest deposition in a shallow-shelf channel system. By contrast, an alternative correlation and interpretation based on geometry and facies is that of an elongate in-situ carbonate buildup. A number of modern analogs of elongate buildups normal to major reef systems are available from which to compare and model the depositional system of Giddings Edwards field. The evaluation of this field serves as an example of using a multiple working hypothesis to develop an accurate exploration model.« less

The Direct Effect of Toroidal Magnetic Fields on Stellar Oscillations: An Analytical Expression for the General Matrix Element

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiefer, René; Schad, Ariane; Roth, Markus

2017-09-10

Where is the solar dynamo located and what is its modus operandi? These are still open questions in solar physics. Helio- and asteroseismology can help answer them by enabling us to study solar and stellar internal structures through global oscillations. The properties of solar and stellar acoustic modes are changing with the level of magnetic activity. However, until now, the inference on subsurface magnetic fields with seismic measures has been very limited. The aim of this paper is to develop a formalism to calculate the effect of large-scale toroidal magnetic fields on solar and stellar global oscillation eigenfunctions and eigenfrequencies.more » If the Lorentz force is added to the equilibrium equation of motion, stellar eigenmodes can couple. In quasi-degenerate perturbation theory, this coupling, also known as the direct effect, can be quantified by the general matrix element. We present the analytical expression of the matrix element for a superposition of subsurface zonal toroidal magnetic field configurations. The matrix element is important for forward calculations of perturbed solar and stellar eigenfunctions and frequency perturbations. The results presented here will help to ascertain solar and stellar large-scale subsurface magnetic fields, and their geometric configuration, strength, and change over the course of activity cycles.« less

Surface manifestations of internal waves investigated by a subsurface buoyant jet: 3. Surface manifestations of internal waves

NASA Astrophysics Data System (ADS)

Bondur, V. G.; Grebenyuk, Yu. V.; Ezhova, E. V.; Kazakov, V. I.; Sergeev, D. A.; Soustova, I. A.; Troitskaya, Yu. I.

2010-08-01

In a large test reservoir at the Institute of Applied Physics, Russian Academy of Sciences, a series of experiments were performed to investigate the surface manifestations of internal waves radiated by a subsurface buoyant jet. The field of currents on the water surface of the reservoir was studied through the distribution of temperature with shallow thermocline. Using Particle Tracking Velocimetry (PTV), the velocity field of surface currents was measured. A theoretical model was developed to calculate the rates of disturbances on the surface. A comparison with experimental data indicated that the calculated data of the surface rate value are overestimated. This discrepancy was explained by the presence of a film of surface-active substances (SASs) with experimentally obtained parameters. Using scale modeling coefficients, we estimated the parameters of internal waves radiated by the subsurface wastewater system and the values of their surface manifestations in field conditions. We estimated the hydrodynamic contrasts in the field of surface waves, which can be caused by these inhomogeneous currents on the surface. For a wind velocity of 5 m/s, the magnitude of the contrast in the field of short waves can reach up to 10-25%, which is detected with confidence by remote-sensing methods.

The Direct Effect of Toroidal Magnetic Fields on Stellar Oscillations: An Analytical Expression for the General Matrix Element

NASA Astrophysics Data System (ADS)

Kiefer, René; Schad, Ariane; Roth, Markus

2017-09-01

Where is the solar dynamo located and what is its modus operandi? These are still open questions in solar physics. Helio- and asteroseismology can help answer them by enabling us to study solar and stellar internal structures through global oscillations. The properties of solar and stellar acoustic modes are changing with the level of magnetic activity. However, until now, the inference on subsurface magnetic fields with seismic measures has been very limited. The aim of this paper is to develop a formalism to calculate the effect of large-scale toroidal magnetic fields on solar and stellar global oscillation eigenfunctions and eigenfrequencies. If the Lorentz force is added to the equilibrium equation of motion, stellar eigenmodes can couple. In quasi-degenerate perturbation theory, this coupling, also known as the direct effect, can be quantified by the general matrix element. We present the analytical expression of the matrix element for a superposition of subsurface zonal toroidal magnetic field configurations. The matrix element is important for forward calculations of perturbed solar and stellar eigenfunctions and frequency perturbations. The results presented here will help to ascertain solar and stellar large-scale subsurface magnetic fields, and their geometric configuration, strength, and change over the course of activity cycles.

Field intercomparison of channel master ADCP with RiverSonde Radar for measuring river discharge

USGS Publications Warehouse

Spain, P.; Marsden, R.; Barrick, D.; Teague, C.; Ruhl, C.

2005-01-01

The RiverSonde radar makes non-contact measurement of a horizontal swath of surface velocity across a river section. This radar, which has worked successfully at several rivers in the Western USA, has shown encouraging correlation with simultaneous measurements of average currents at one level recorded by an acoustic travel-time system. This work reports a field study intercomparing data sets from a 600 kHz Channel Master ADCP with the RiverSonde radar. The primary goal was to begin to explore the robustness of the radar data as a reliable index of discharge. This site Is at Three Mile Slough in Northern California, USA. The larger intent of the work is to examine variability in space and time of the radar's surface currents compared with subsurface flows across the river section. Here we examine data from a couple of periods with strong winds. ?? 2005 IEEE.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joel E. Kostka

This project represented a joint effort between Oak Ridge National Laboratory (ORNL), the University of Tennessee (UT), and Florida State University (FSU). ORNL served as the lead in-stitution with Dr. A.V. Palumbo responsible for project coordination, integration, and deliver-ables. In situ uranium bioremediation is focused on biostimulating indigenous microorganisms through a combination of pH neutralization and the addition of large amounts of electron donor. Successful biostimulation of U(VI) reduction has been demonstrated in the field and in the laboratory. However, little data is available on the dynamics of microbial populations capable of U(VI) reduction, and the differences in the microbialmore » community dynamics between proposed electron donors have not been explored. In order to elucidate the potential mechanisms of U(VI) reduction for optimization of bioremediation strategies, structure-function relationships of microbial populations were investigated in microcosms of subsurface materials cocontaminated with radionuclides and nitrate from the Oak Ridge Field Research Center (ORFRC), Oak Ridge, Tennessee.« less

A field study of colloid transport in surface and subsurface flows

NASA Astrophysics Data System (ADS)

Zhang, Wei; Tang, Xiang-Yu; Xian, Qing-Song; Weisbrod, Noam; Yang, Jae E.; Wang, Hong-Lan

2016-11-01

Colloids have been recognized to enhance the migration of strongly-sorbing contaminants. However, few field investigations have examined combined colloid transport via surface runoff and subsurface flows. In a headwater catchment of the upper Yangtze River, a 6 m (L) by 4 m (W) sloping (6°) farmland plot was built by cement walls to form no-flow side boundaries. The plot was monitored in the summer of 2014 for the release and transport of natural colloids via surface runoff and subsurface flows (i.e., the interflow from the soil-mudrock interface and fracture flow from the mudrock-sandstone interface) in response to rain events. The water sources of the subsurface flows were apportioned to individual rain events using a two end-member model (i.e., mobile pre-event soil water extracted by a suction-cup sampler vs. rainwater (event water)) based on δ18O measurements. For rain events with high preceding soil moisture, mobile pre-event soil water was the main contributor (generally >60%) to the fracture flow. The colloid concentration in the surface runoff was 1-2 orders of magnitude higher than that in the subsurface flows. The lowest colloid concentration was found in the subsurface interflow, which was probably the result of pore-scale colloid straining mechanisms. The rainfall intensity and its temporal variation govern the dynamics of the colloid concentrations in both surface runoff and subsurface flows. The duration of the antecedent dry period affected not only the relative contributions of the rainwater and the mobile pre-event soil water to the subsurface flows but also the peak colloid concentration, particularly in the fracture flow. The <10 μm fine colloid size fraction accounted for more than 80% of the total suspended particles in the surface runoff, while the colloid size distributions of both the interflow and the fracture flow shifted towards larger diameters. These results highlight the need to avoid the application of strongly-sorbing agrochemicals (e.g., pesticides, phosphorus fertilizers) immediately before rainfall following a long no-rain period because their transport in association with colloids may occur rapidly over long distances via both surface runoff and subsurface flows with rainfall.

SFDBSI_GLS v. 1.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poppeliers, Christian

Matlab code for inversion of frequency domain, electrostatic geophysical data in terms of scalar scattering amplitudes in the subsurface. The data is assumed to be the difference between two measurements: electric field measurements prior to the injection of an electrically conductive proppant, and the electric field measurements after proppant injection. The proppant is injected into the subsurface via a well, and its purpose is to prop open fractures created by hydraulic fracturing. In both cases the illuminating electric field is assumed to be a vertically incident plane wave. The inversion strategy is to solve a set of linear system ofmore » equations, where each equation defines the amplitude of a candidate scattering volume. The model space is defined by M potential scattering locations and the frequency domain (of which there are k frequencies) data are recorded on N receivers. The solution thus solves a kN x M system of linear equations for M scalar amplitudes within the user-defined solution space. Practical Application: Oilfield environments where observed electrostatic geophysical data can reasonably be assumed to be scattered by subsurface proppant volumes. No field validation examples have so far been provided.« less

Uncertainty in the modelling of spatial and temporal patterns of shallow groundwater flow paths: The role of geological and hydrological site information

NASA Astrophysics Data System (ADS)

Woodward, Simon J. R.; Wöhling, Thomas; Stenger, Roland

2016-03-01

Understanding the hydrological and hydrogeochemical responses of hillslopes and other small scale groundwater systems requires mapping the velocity and direction of groundwater flow relative to the controlling subsurface material features. Since point observations of subsurface materials and groundwater head are often the basis for modelling these complex, dynamic, three-dimensional systems, considerable uncertainties are inevitable, but are rarely assessed. This study explored whether piezometric head data measured at high spatial and temporal resolution over six years at a hillslope research site provided sufficient information to determine the flow paths that transfer nitrate leached from the soil zone through the shallow saturated zone into a nearby wetland and stream. Transient groundwater flow paths were modelled using MODFLOW and MODPATH, with spatial patterns of hydraulic conductivity in the three material layers at the site being estimated by regularised pilot point calibration using PEST, constrained by slug test estimates of saturated hydraulic conductivity at several locations. Subsequent Null Space Monte Carlo uncertainty analysis showed that this data was not sufficient to definitively determine the spatial pattern of hydraulic conductivity at the site, although modelled water table dynamics matched the measured heads with acceptable accuracy in space and time. Particle tracking analysis predicted that the saturated flow direction was similar throughout the year as the water table rose and fell, but was not aligned with either the ground surface or subsurface material contours; indeed the subsurface material layers, having relatively similar hydraulic properties, appeared to have little effect on saturated water flow at the site. Flow path uncertainty analysis showed that, while accurate flow path direction or velocity could not be determined on the basis of the available head and slug test data alone, the origin of well water samples relative to the material layers and site contour could still be broadly deduced. This study highlights both the challenge of collecting suitably informative field data with which to characterise subsurface hydrology, and the power of modern calibration and uncertainty modelling techniques to assess flow path uncertainty in hillslopes and other small scale systems.

Understanding heterogeneity and data assimilation in karst groundwater surface water interactions: The role of geophysics and hydrologic models in a semi-confined aquifer

NASA Astrophysics Data System (ADS)

Meyerhoff, Steven B.

Groundwater and surface water historically have been treated as different entities. Due to this, planning and development of groundwater and surface water resources, both quantity and quality are often also treated separately. Recently, there has been work to characterize groundwater and surface water as a single system. Karstic systems are widely influenced by these interactions due to varying permeability, fracture geometry and porosity. Here, three different approaches are used to characterize groundwater surface water interactions in karstic environments. 1) A hydrologic model, ParFlow, is conditioned with known subsurface data to determine whether a reduction in subsurface uncertainty will enhance the prediction of surface water variables. A reduction in subsurface uncertainty resulted in substantial reductions in uncertainty in Hortonian runoff and less reductions in Dunne runoff. 2) Geophysical data is collected at a field site in O'leno State Park, Florida to visualize groundwater and surface water interactions in karstic environments. Significant changes in resistivity are seen through time at two locations. It is hypothesized that these changes are related to changing fluid source waters (e.g groundwater or surface water). 3). To confirm these observations an ensemble of synthetic forward models are simulated, inverted and compared directly with field observations and End-Member-Mixing-Analysis (EMMA). Field observations and synthetic models have comparable resistivity anomalies patterns and mixing fractions. This allows us to characterize and quantify subsurface mixing of groundwater and surface in karst environments. These three approaches (hydrologic models, field data and forward model experiments), (1) show the complexity and dynamics of groundwater and surface mixing in karstic environments in varying flow conditions, (2) showcase a novel geophysical technique to visualize groundwater and surface water interactions and (3) confirm hypothesis of flow and mixing in subsurface karst environments.

Field study and simulation of diurnal temperature effects on infiltration and variably saturated flow beneath an ephemeral stream

USGS Publications Warehouse

Dudek Ronan, Anne; Prudic, David E.; Thodal, Carl E.; Constantz, Jim

1998-01-01

Two experiments were performed to investigate flow beneath an ephemeral stream and to estimate streambed infiltration rates. Discharge and stream-area measurements were used to determine infiltration rates. Stream and subsurface temperatures were used to interpret subsurface flow through variably saturated sediments beneath the stream. Spatial variations in subsurface temperatures suggest that flow beneath the streambed is dependent on the orientation of the stream in the canyon and the layering of the sediments. Streamflow and infiltration rates vary diurnally: Streamflow is lowest in late afternoon when stream temperature is greatest and highest in early morning when stream temperature is least. The lower afternoon Streamflow is attributed to increased infiltration rates; evapotranspiration is insufficient to account for the decreased Streamflow. The increased infiltration rates are attributed to viscosity effects on hydraulic conductivity from increased stream temperatures. The first set of field data was used to calibrate a two-dimensional variably saturated flow model that includes heat transport. The model was calibrated to (1) temperature fluctuations in the subsurface and (2) infiltration rates determined from measured Streamflow losses. The second set of field data was to evaluate the ability to predict infiltration rates on the basis of temperature measurements alone. Results indicate that the variably saturated subsurface flow depends on downcanyon layering of the sediments. They also support the field observations in indicating that diurnal changes in infiltration can be explained by temperature dependence of hydraulic conductivity. Over the range of temperatures and flows monitored, diurnal stream temperature changes can be used to estimate streambed infiltration rates. It is often impractical to maintain equipment for determining infiltration rates by traditional means; however, once a model is calibrated using both infiltration and temperature data, only relatively inexpensive temperature monitoring can later yield infiltration rates that are within the correct order of magnitude.

Subsurface microbial habitats on Mars

NASA Technical Reports Server (NTRS)

Boston, P. J.; Mckay, C. P.

1991-01-01

We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on geothermal hot spots existing below the near or deep subsurface of Mars. Recent advances in the comparatively new field of deep subsurface microbiology have revealed previously unsuspected rich aerobic and anaerobic microbal communities far below the surface of the Earth. Such habitats, protected from the grim surface conditions on Mars, could receive warmth from below and maintain water in its liquid state. In addition, geothermally or volcanically reduced gases percolating from below through a microbiologically active zone could provide the reducing power needed for a closed or semi-closed microbial ecosystem to thrive.

Bacterial communities associated with subsurface geochemical processes in continental serpentinite springs.

PubMed

Brazelton, William J; Morrill, Penny L; Szponar, Natalie; Schrenk, Matthew O

2013-07-01

Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats.

Bacterial Communities Associated with Subsurface Geochemical Processes in Continental Serpentinite Springs

PubMed Central

Morrill, Penny L.; Szponar, Natalie; Schrenk, Matthew O.

2013-01-01

Reactions associated with the geochemical process of serpentinization can generate copious quantities of hydrogen and low-molecular-weight organic carbon compounds, which may provide energy and nutrients to sustain subsurface microbial communities independently of the photosynthetically supported surface biosphere. Previous microbial ecology studies have tested this hypothesis in deep sea hydrothermal vents, such as the Lost City hydrothermal field. This study applied similar methods, including molecular fingerprinting and tag sequencing of the 16S rRNA gene, to ultrabasic continental springs emanating from serpentinizing ultramafic rocks. These molecular surveys were linked with geochemical measurements of the fluids in an interdisciplinary approach designed to distinguish potential subsurface organisms from those derived from surface habitats. The betaproteobacterial genus Hydrogenophaga was identified as a likely inhabitant of transition zones where hydrogen-enriched subsurface fluids mix with oxygenated surface water. The Firmicutes genus Erysipelothrix was most strongly correlated with geochemical factors indicative of subsurface fluids and was identified as the most likely inhabitant of a serpentinization-powered subsurface biosphere. Both of these taxa have been identified in multiple hydrogen-enriched subsurface habitats worldwide, and the results of this study contribute to an emerging biogeographic pattern in which Betaproteobacteria occur in near-surface mixing zones and Firmicutes are present in deeper, anoxic subsurface habitats. PMID:23584766

Evaluating permafrost thaw vulnerabilities and hydrologic impacts in boreal Alaska (USA) watersheds using field data and cryohydrogeologic modeling

NASA Astrophysics Data System (ADS)

Walvoord, M. A.; Voss, C.; Ebel, B. A.; Minsley, B. J.

2017-12-01

Permafrost environments undergo changes in hydraulic, thermal, chemical, and mechanical subsurface properties upon thaw. These property changes must be considered in addition to alterations in hydrologic, thermal, and topographic boundary conditions when evaluating shifts in the movement and storage of water in arctic and sub-arctic boreal regions. Advances have been made in the last several years with respect to multiscale geophysical characterization of the subsurface and coupled fluid and energy transport modeling of permafrost systems. Ongoing efforts are presented that integrate field data with cryohydrogeologic modeling to better understand and anticipate changes in subsurface water resources, fluxes, and flowpaths caused by climate warming and permafrost thawing. Analyses are based on field data from several sites in interior Alaska (USA) that span a broad north-south transition from continuous to discontinuous permafrost. These data include soil hydraulic and thermal properties and shallow permafrost distribution. The data guide coupled fluid and energy flow simulations that incorporate porewater liquid/ice phase change and the accompanying modifications in hydraulic and thermal subsurface properties. Simulations are designed to assess conditions conducive to active layer thickening and talik development, both of which are expected to affect groundwater storage and flow. Model results provide a framework for identifying factors that control the rates of permafrost thaw and associated hydrologic responses, which in turn influence the fate and transport of carbon.

Enhancing management of fall-applied poultry litter with cover crop and subsurface band placement in no-till cotton

USDA-ARS?s Scientific Manuscript database

Whether yield reduction risk of cotton fertilized with fall-applied poultry litter in regions with warm fall or winter months can be minimized by applying the litter in subsurface bands in conjunction with winter cover crop is unknown. A field study was conducted in Mississippi to test whether litte...

Subsurface Optical Microscopy of Coarse Grain Spinels. Phase 1

DTIC Science & Technology

2013-12-01

A 456 nm LED line bar illuminated in figure 15 and a Xenon fiber optic bar illuminator is shown for figure 16. The optical in situ or subsurface ... imaging of coarse grain spinels and AlONs is optically more complex than expected. An overhead view of the side illumination field is shown in figure 20

Magnetic perturbation inspection of inner bearing races

NASA Technical Reports Server (NTRS)

Barton, J. R.; Lankford, J.

1972-01-01

Approximately 100 inner race bearings were inspected nondestructively prior to endurance testing. Two of the bearings which failed during testing spalled at the sites of subsurface inclusions previously detected by using magnetic field perturbation. At other sites initially judged to be suspect, subsurface inclusion-nucleated cracking was observed. Inspection records and metallurgical sectioning results are presented and discussed.

Interpretation of Data from Uphole Refraction Surveys

DTIC Science & Technology

1980-06-01

Seismic refraction Seismic refraction method Seismic surveys Subsurface exploration ""-. 20, AI0SrRACT -(CmtuamU 00MvaO eL If naaaaamr and Identlfyby...by the presence of subsurface cavities and large cavities are identifiable, the sensitivity of the method is marginal for practical use in cavity...detection. Some cavities large enough to be of engineering signifi- cance (e.g., a tunnel of h-m diameter) may be practically undetectable by this method

Nitrous Oxide Emissions From Northern Forested and Harvested Ecosystems

NASA Astrophysics Data System (ADS)

Kavanaugh, K. M.; Kellman, L. M.

2005-12-01

Very little is known about how deforestation alters the soil subsurface production and surface emissions of N2O from northern forest soils. Soil N2O surface fluxes and subsurface concentrations from two 3 year old harvested and intact forest pairs of contrasting soil texture were monitored during the 2004 and 2005 growing seasons in the Acadian forest of Atlantic Canada in order to: 1) quantify N2O emissions associated with each land-use type, 2) examine spatial and temporal variations in subsurface concentrations and surface fluxes at each site, and 3) determine the suitability of a photoacoustic gas monitor (PGM) for in- situ field measurements vs. field sample collection and laboratory analysis on a gas chromatograph. Each site was instrumented with 11 permanent collars for surface flux measurements designed to capture the microsite variability at the sites. Subsurface soil gas samplers, designed to identify the important zones of N2O production in the vertical profile were installed at depths of 0, 10, 20 and 35 cm below the organic-mineral soil interface. Surface fluxes were measured with non-steady-state vented surface flux chambers with measurements of all surface flux and subsurface data made on a bi-weekly basis. Results suggest that spatial and temporal variability in surface emissions are very high and routinely close to zero. Subsurface profile concentration data shows vertical concentration profiles at intact forest sites with concentrations close to atmospheric, while harvested sites show a pattern of increasing N2O concentration with depth, reaching a maximum of approximately 27000ppb at 35cm.

Denitrifying Bacteria from the Genus Rhodanobacter Dominate Bacterial Communities in the Highly Contaminated Subsurface of a Nuclear Legacy Waste Site

PubMed Central

Green, Stefan J.; Prakash, Om; Jasrotia, Puja; Overholt, Will A.; Cardenas, Erick; Hubbard, Daniela; Tiedje, James M.; Watson, David B.; Schadt, Christopher W.; Brooks, Scott C.

2012-01-01

The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of rRNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure and that denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower-pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as the concentration of nitrogen species, oxygen level, and sampling season, did not appear to strongly influence the distribution of Rhodanobacter bacteria. The results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment. PMID:22179233

Determining the 3D Subsurface Density Structure of Taurus Littrow Valley Using Apollo 17 Gravity Data

NASA Technical Reports Server (NTRS)

Urbancic, N.; Ghent, R.; Stanley, S,; Johnson, C. L.; Carroll, K. A.; Hatch, D.; Williamson, M. C.; Garry, W. B.; Talwani, M.

2016-01-01

Surface gravity surveys can detect subsurface density variations that can reveal subsurface geologic features. In 1972, the Apollo 17 (A17) mission conducted the Traverse Gravimeter Experiment (TGE) using a gravimeter that measured the local gravity field near Taurus Littrow Valley (TLV), located on the south-eastern rim of the Serenitatis basin. TLV is hypothesized to be a basaltfilled radial graben resulting from the impact that formed Mare Serenitatis. It is bounded by both the North and South Massifs (NM and SM) as well as other smaller mountains to the East that are thought to be mainly composed of brecciated highland material. The TGE is the first and only successful gravity survey on the surface of the Moon. Other more recent satellite surveys, such as NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission (2011- 2012), have produced the best global gravity field to date (approx. 13km resolution). However, these satellite surveys are not sensitive enough to detect fine-scale (<1km) lunar subsurface structures. This underscores the value of the data collected at the surface by A17. In the original analysis of the data a 2D forward-modelling approach was used to derive a thickness of the subsurface basalt layer of 1.0 km by assuming a simple flat-faced rectangular geometry and using densities derived from Apollo lunar samples. We are investigating whether modern 3D modelling techniques in combination with high-resolution topographical and image datasets can reveal additional fine-scale subsurface structure in TLV.

Simulating oil droplet dispersal from the Deepwater Horizon spill with a Lagrangian approach

USGS Publications Warehouse

North, Elizabeth W.; Schlag, Zachary; Adams, E. Eric; Sherwood, Christopher R.; He, Ruoying; Hyun, Hoon; Socolofsky, Scott A.

2011-01-01

An analytical multiphase plume model, combined with time-varying flow and hydrographic fields generated by the 3-D South Atlantic Bight and Gulf of Mexico model (SABGOM) hydrodynamic model, were used as input to a Lagrangian transport model (LTRANS), to simulate transport of oil droplets dispersed at depth from the recent Deepwater Horizon MC 252 oil spill. The plume model predicts a stratification-dominated near field, in which small oil droplets detrain from the central plume containing faster rising large oil droplets and gas bubbles and become trapped by density stratification. Simulated intrusion (trap) heights of ∼ 310–370 m agree well with the midrange of conductivity-temperature-depth observations, though the simulated variation in trap height was lower than observed, presumably in part due to unresolved variability in source composition (percentage oil versus gas) and location (multiple leaks during first half of spill). Simulated droplet trajectories by the SABGOM-LTRANS modeling system showed that droplets with diameters between 10 and 50 μm formed a distinct subsurface plume, which was transported horizontally and remained in the subsurface for >1 month. In contrast, droplets with diameters ≥90 μm rose rapidly to the surface. Simulated trajectories of droplets ≤50 μm in diameter were found to be consistent with field observations of a southwest-tending subsurface plume in late June 2010 reported by Camilli et al. [2010]. Model results suggest that the subsurface plume looped around to the east, with potential subsurface oil transport to the northeast and southeast. Ongoing work is focusing on adding degradation processes to the model to constrain droplet dispersal.

Imaging strategies using focusing functions with applications to a North Sea field

NASA Astrophysics Data System (ADS)

da Costa Filho, C. A.; Meles, G. A.; Curtis, A.; Ravasi, M.; Kritski, A.

2018-04-01

Seismic methods are used in a wide variety of contexts to investigate subsurface Earth structures, and to explore and monitor resources and waste-storage reservoirs in the upper ˜100 km of the Earth's subsurface. Reverse-time migration (RTM) is one widely used seismic method which constructs high-frequency images of subsurface structures. Unfortunately, RTM has certain disadvantages shared with other conventional single-scattering-based methods, such as not being able to correctly migrate multiply scattered arrivals. In principle, the recently developed Marchenko methods can be used to migrate all orders of multiples correctly. In practice however, using Marchenko methods are costlier to compute than RTM—for a single imaging location, the cost of performing the Marchenko method is several times that of standard RTM, and performing RTM itself requires dedicated use of some of the largest computers in the world for individual data sets. A different imaging strategy is therefore required. We propose a new set of imaging methods which use so-called focusing functions to obtain images with few artifacts from multiply scattered waves, while greatly reducing the number of points across the image at which the Marchenko method need be applied. Focusing functions are outputs of the Marchenko scheme: they are solutions of wave equations that focus in time and space at particular surface or subsurface locations. However, they are mathematical rather than physical entities, being defined only in reference media that equal to the true Earth above their focusing depths but are homogeneous below. Here, we use these focusing functions as virtual source/receiver surface seismic surveys, the upgoing focusing function being the virtual received wavefield that is created when the downgoing focusing function acts as a spatially distributed source. These source/receiver wavefields are used in three imaging schemes: one allows specific individual reflectors to be selected and imaged. The other two schemes provide either targeted or complete images with distinct advantages over current RTM methods, such as fewer artifacts and artifacts that occur in different locations. The latter property allows the recently published `combined imaging' method to remove almost all artifacts. We show several examples to demonstrate the methods: acoustic 1-D and 2-D synthetic examples, and a 2-D line from an ocean bottom cable field data set. We discuss an extension to elastic media, which is illustrated by a 1.5-D elastic synthetic example.

Large-scale 3D inversion of marine controlled source electromagnetic data using the integral equation method

NASA Astrophysics Data System (ADS)

Zhdanov, M. S.; Cuma, M.; Black, N.; Wilson, G. A.

2009-12-01

The marine controlled source electromagnetic (MCSEM) method has become widely used in offshore oil and gas exploration. Interpretation of MCSEM data is still a very challenging problem, especially if one would like to take into account the realistic 3D structure of the subsurface. The inversion of MCSEM data is complicated by the fact that the EM response of a hydrocarbon-bearing reservoir is very weak in comparison with the background EM fields generated by an electric dipole transmitter in complex geoelectrical structures formed by a conductive sea-water layer and the terranes beneath it. In this paper, we present a review of the recent developments in the area of large-scale 3D EM forward modeling and inversion. Our approach is based on using a new integral form of Maxwell’s equations allowing for an inhomogeneous background conductivity, which results in a numerically effective integral representation for 3D EM field. This representation provides an efficient tool for the solution of 3D EM inverse problems. To obtain a robust inverse model of the conductivity distribution, we apply regularization based on a focusing stabilizing functional which allows for the recovery of models with both smooth and sharp geoelectrical boundaries. The method is implemented in a fully parallel computer code, which makes it possible to run large-scale 3D inversions on grids with millions of inversion cells. This new technique can be effectively used for active EM detection and monitoring of the subsurface targets.

Remotely Exploring Deeper-Into-Matter by Non-Contact Detection of Audible Transients Excited by Laser Radiation

PubMed Central

Moros, Javier; Gaona, Inmaculada; Laserna, J. Javier

2017-01-01

An acoustic spectroscopic approach to detect contents within different packaging, with substantially wider applicability than other currently available subsurface spectroscopies, is presented. A frequency-doubled Nd:YAG (neodymium-doped yttrium aluminum garnet) pulsed laser (13 ns pulse length) operated at 1 Hz was used to generate the sound field of a two-component system at a distance of 50 cm. The acoustic emission was captured using a unidirectional microphone and analyzed in the frequency domain. The focused laser pulse hitting the system, with intensity above that necessary to ablate the irradiated surface, transferred an impulsive force which led the structure to vibrate. Acoustic airborne transients were directly radiated by the vibrating elastic structure of the outer component that excited the surrounding air in contact with. However, under boundary conditions, sound field is modulated by the inner component that modified the dynamical integrity of the system. Thus, the resulting frequency spectra are useful indicators of the concealed content that influences the contributions originating from the wall of the container. High-quality acoustic spectra could be recorded from a gas (air), liquid (water), and solid (sand) placed inside opaque chemical-resistant polypropylene and stainless steel sample containers. Discussion about effects of laser excitation energy and sampling position on the acoustic emission events is reported. Acoustic spectroscopy may complement the other subsurface alternative spectroscopies, severely limited by their inherent optical requirements for numerous detection scenarios. PMID:29261126

Asparagus densiflorus in a vertical subsurface flow phytoreactor for treatment of real textile effluent: A lab to land approach for in situ soil remediation.

PubMed

Watharkar, Anuprita D; Kadam, Suhas K; Khandare, Rahul V; Kolekar, Parag D; Jeon, Byong-Hun; Jadhav, Jyoti P; Govindwar, Sanjay P

2018-05-30

This study explores the potential of Asparagus densiflorus to treat disperse Rubin GFL (RGFL) dye and a real textile effluent in constructed vertical subsurface flow (VSbF) phytoreactor; its field cultivation for soil remediation offers a real green and economic way of environmental management. A. densiflorus decolorized RGFL (40 gm L -1 ) up to 91% within 48 h. VSbF phytoreactor successfully reduced American dye manufacture institute (ADMI), BOD, COD, Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) of real textile effluent by 65%, 61%, 66%, 48% and 66%, respectively within 6 d. Oxidoreductive enzymes such as laccase (138%), lignin peroxidase (129%), riboflavin reductase (111%) were significantly expressed during RGFL degradation in A. densiflorus roots, while effluent transformation caused noteworthy induction of enzymes like, tyrosinase (205%), laccase (178%), veratryl oxidase (52%). Based on enzyme activities, UV-vis spectroscopy, FTIR and GC-MS results; RGFL was proposed to be transformed to 4-amino-3- methylphenyl (hydroxy) oxoammonium and N, N-diethyl aniline. Anatomical study of the advanced root tissue of A. densiflorus exhibited the progressive dye accumulation and removal during phytoremediation. HepG2 cell line and phytotoxicity study demonstrated reduced toxicity of biotransformed RGFL and treated effluent by A. densiflorus, respectively. On field remediation study revealed a noteworthy removal (67%) from polluted soil within 30 d. Copyright © 2018 Elsevier Inc. All rights reserved.

Airborne EM survey in volcanoes : Application to a volcanic hazards assessment

NASA Astrophysics Data System (ADS)

Mogi, T.

2010-12-01

Airborne electromagnetics (AEM) is a useful tool for investigating subsurface structures of volcanoes because it can survey large areas involving inaccessible areas. Disadvantages include lower accuracy and limited depth of investigation. AEM has been widely used in mineral exploration in frontier areas, and have been applying to engineering and environmental fields, particularly in studies involving active volcanoes. AEM systems typically comprise a transmitter and a receiver on an aircraft or in a towed bird, and although effective for surveying large areas, their penetration depth is limited because the distance between the transmitter and receiver is small and higher-frequency signals are used. To explore deeper structures using AEM, a semi-airborne system called GRounded Electrical source Airborne Transient ElectroMagnetics (GREATEM) has been developed. The system uses a grounded-electrical-dipole as the transmitter and generates horizontal electric fields. The GREATEM technology, first proposed by Mogi et al. (1998), has recently been improved and used in practical surveys (Mogi et al., 2009). The GREATEM survey system was developed to increase the depth of investigation possible using AEM. The method was tested in some volcanoes at 2004-2005. Here I will talk about some results of typical AEM surveys and GREATEM surveys in some volcanoes in Japan to mitigate hazards associated with volcano eruption. Geologic hazards caused by volcanic eruptions can be mitigated by a combination of prediction, preparedness and land-use control. Risk management depends on the identification of hazard zones and forecasting of eruptions. Hazard zoning involves the mapping of deposits which have formed during particular phases of volcanic activity and their extrapolation to identify the area which would be likely to suffer a similar hazard at some future time. The mapping is usually performed by surface geological surveys of volcanic deposits. Resistivity mapping by AEM is useful tool to identify each volcanic deposit on the surface and at shallower depth as well. This suggests that more efficient hazard map involving subsurface information can be supplied by AEM resistivity mapping.

Assessment of Nitrate-N Load in Subsurface Drainage Water from the Agricultural Fields in the Fergana Valley, Uzbekistan

NASA Astrophysics Data System (ADS)

Kenjabaev, S.; Forkutsa, I.; Dukhovny, V.; Frede, H. G.

2012-04-01

Leaching of nitrate-N (NO3-) from irrigated agricultural land and water contamination have become a worldwide concern. This study was conducted to investigate amount of nitrate-N leached to groundwater and surface water from irrigated cotton, winter wheat and maize fields in the Fergana Valley (Uzbekistan). Therefore at two sites ("Akbarabad" and "Azizbek") equipped with closed horizontal drainage system during 2010-2011 vegetation seasons we monitored water flow, nutrient concentrations and salinity at surface and subsurface drains, at irrigation canals and groundwater. We also applied stable isotopes (δ2H and δ18O) method in order to investigate the source of drainage water runoff. Discussed are results of 2010. Farmers fertilized cotton fields with ammonium nitrate of 350-450 kg ha-1 in "Akbarabad" and 700 kg ha-1 in "Azizbek" sites. In winter wheat and maize fields (in "Akbarabad") about 500 kg ha-1 of ammonium nitrate were applied. Cotton fields were irrigated with 2700 m3 ha-1 ("Akbarabad") and 3500 m3 ha-1 ("Azizbek"). In winter wheat and maize fields applied irrigation water amounted to 3900 m3 ha-1 and 723 m3 ha-1, respectively. Frequent groundwater and subsurface drainage water sampling revealed that nitrate leaching occurred mostly during and right after the irrigation events. The estimated average nitrate-N concentration in subsurface drainage water in "Akbarabad" was slightly higher (9 mg l-1) than in "Azizbek" (8 mg l-1). During July-November (2010), in average, nitrate-N losses through subsurface drainage amounted to 24 kg ha-1 in "Akbarabad" and 18 kg ha-1 in "Azizbek". The salinity of drainage water at both sites was similar and varied between 2.3-2.7 dS m-1. Preliminary results of isotope signals of studied water (precipitation, drainage, irrigation and ground water) indicate that the source of drainage water runoff comes from the irrigation water, while the contribution of rainfall is negligible. It is planned to run simulations with DRAINMOD model for further investigation of water and N balances of the selected sites. Developed recommendations for farmers on optimum irrigation water amounts and N fertilization will allow reducing environmental risks in agricultural lands of the Fergana Valley.

Effect of subsurface heterogeneity on free-product recovery from unconfined aquifers

NASA Astrophysics Data System (ADS)

Kaluarachchi, Jagath J.

1996-03-01

Free-product record system designs for light-hydrocarbon-contaminated sites were investigated to evaluate the effects of subsurface heterogeneity using a vertically integrated three-phase flow model. The input stochastic variable of the areal flow analysis was the log-intrinsic permeability and it was generated using the Turning Band method. The results of a series of hypothetical field-scale simulations showed that subsurface heterogeneity has a substantial effect on free-product recovery predictions. As the heterogeneity increased, the recoverable oil volume decreased and the residual trapped oil volume increased. As the subsurface anisotropy increased, these effects together with free- and total-oil contaminated areas were further enhanced. The use of multiple-stage water pumping was found to be insignificant compared to steady uniform pumping due to reduced recovery efficiency and increased residual oil volume. This observation was opposite to that produced under homogeneous scenarios. The effect of subsurface heterogeneity was enhanced at relatively low water pumping rates. The difference in results produced by homogeneous and heterogeneous simulations was substantial, indicating greater attention should be paid in modeling free-product recovery systems with appropriate subsurface heterogeneity.

Footprints on Mars

NASA Technical Reports Server (NTRS)

Drake, Bret G.

2013-01-01

The first three human missions to Mars should be to three different geographic sites. Maximize mobility to extend the reach of human exploration beyond the landing site. Maximize the amount of time that the astronauts spend exploring the planet. Provide subsurface access. Return a minimum of 250 kg of samples to Earth.

Mars Analog Research and Technology Experiment (MARTE): A Simulated Mars Drilling Mission to Search for Subsurface Life at the Rio Tinto, Spain

NASA Technical Reports Server (NTRS)

Stoker, Carol; Lemke, Larry; Mandell, Humboldt; McKay, David; George, Jeffrey; Gomez-Alvera, Javier; Amils, Ricardo; Stevens, Todd; Miller, David

2003-01-01

The MARTE (Mars Astrobiology Research and Technology Experiment) project was selected by the new NASA ASTEP program, which supports field experiments having an equal emphasis on Astrobiology science and technology development relevant to future Astrobiology missions. MARTE will search for a hypothesized subsurface anaerobic chemoautotrophic biosphere in the region of the Tinto River in southwestern Spain while also demonstrating technology needed to search for a subsurface biosphere on Mars. The experiment is informed by the strategy for searching for life on Mars.

Technical Challenges of Drilling on Mars

NASA Technical Reports Server (NTRS)

Briggs, Geoffrey; Gross, Anthony; Condon, Estelle (Technical Monitor)

2002-01-01

In the last year, NASA's Mars science advisory committee (MEPAG: Mars Exploration Payload Advisory Group) has formally recommended that deep drilling be undertaken as a priority investigation to meet astrobiology and geology goals. This proposed new dimension in Mars exploration has come about for several reasons. Firstly, geophysical models of the martian subsurface environment indicate that we may well find liquid water (in the form of brines) under ground-ice at depths of several kilometers near the equator. On Earth we invariably find life forms associated with any environmental niche that supports liquid water. New data from the Mars Global Surveyor have shown that the most recent volcanism on Mars is very young so we cannot rule out contemporary volcanism -- in which case subsurface temperatures consistent with having water in its liquid phase may be found at relatively shallow depths. Secondly, in recent decades we have learned to our surprise that the Earth's subsurface (microbial) biosphere extends to depths of many kilometers and this discovery provides the basis for planning to explore the martian subsurface in search of ancient or even extant microbial life forms. We know (from Viking measurements) that all the biogenic elements (C, H, O, N, P, S) are available on Mars. What we therefore hope to learn is whether or not the evolution of life is inevitable given the necessary ingredients and, by implication, whether the Universe may be teeming with life. The feasibility of drilling deep into the surface of Mars has been the subject of increasing attention within NASA (and more recently among some of its international partners) for several years and this led to a broad-based feasibility study carried out by the Los Alamos National Laboratory and, subsequently, to the development of several hardware prototypes. This paper is intended to provide a general survey of that activity.

A technical investigation on tools and concepts for sustainable management of the subsurface in The Netherlands.

PubMed

Griffioen, Jasper; van Wensem, Joke; Oomes, Justine L M; Barends, Frans; Breunese, Jaap; Bruining, Hans; Olsthoorn, Theo; Stams, Alfons J M; van der Stoel, Almer E C

2014-07-01

In response to increasing use of the subsurface, there is a need to modernise policies on sustainable use of the subsurface. This holds in particular for the densely populated Netherlands. We aimed to analyse current practice of subsurface management and the associated pressure points and to establish a conceptual overview of the technical issues related to sustainable management of the subsurface. Case studies on the exploitation of subsurface resources (including spatial use of the subsurface) were analysed, examining social relevance, environmental impact, pressure points and management solutions. The case studies ranged from constructing underground garages to geothermal exploitation. The following issues were identified for the technological/scientific aspects: site investigation, suitability, risk assessment, monitoring and measures in the event of failure. Additionally, the following general issues were identified for the administrative aspects: spatial planning, option assessment, precaution, transparency, responsibility and liability. These issues were explored on their technological implications within the framework of sustainable management of the subsurface. This resulted into the following key aspects: (1) sustainability assessment, (2) dealing with uncertainty and (3) policy instruments and governance. For all three aspects, different options were identified which might have a legal, economic or ethical background. The technological implications of these backgrounds have been identified. A set of recommendations for sustainable management of the subsurface resources (incl. space) was established: (1) management should be driven by scarcity, (2) always implement closed loop monitoring when the subsurface activities are high-risk, (3) when dealing with unknown features and heterogeneity, apply the precautionary principle, (4) responsibility and liability for damage must be set out in legislation and (5) sustainability should be incorporated in all relevant legislation and not only in environmental legislation. Other aspects to be considered are the reversibility of the impacts from subsurface activities and the abandonment of installations. Copyright © 2014 Elsevier B.V. All rights reserved.

Planetary Drilling and Resources at the Moon and Mars

NASA Technical Reports Server (NTRS)

George, Jeffrey A.

2012-01-01

Drilling on the Moon and Mars is an important capability for both scientific and resource exploration. The unique requirements of spaceflight and planetary environments drive drills to different design approaches than established terrestrial technologies. A partnership between NASA and Baker Hughes Inc. developed a novel approach for a dry rotary coring wireline drill capable of acquiring continuous core samples at multi-meter depths for low power and mass. The 8.5 kg Bottom Hole Assembly operated at 100 We and without need for traditional drilling mud or pipe. The technology was field tested in the Canadian Arctic in sandstone, ice and frozen gumbo. Planetary resources could play an important role in future space exploration. Lunar regolith contains oxygen and metals, and water ice has recently been confirmed in a shadowed crater at the Moon.s south pole. Mars possesses a CO2 atmosphere, frozen water ice at the poles, and indications of subsurface aquifers. Such resources could provide water, oxygen and propellants that could greatly simplify the cost and complexity of exploration and survival. NASA/JSC/EP/JAG

Surface and subsurface sensor performance in acoustically detecting western drywood termites in naturally infested boards.

Treesearch

V.R. Lewis; A.B. Power; M.I. Haverty

2004-01-01

Field-collected boards showing visual signs of damage by the western drywood termite, Incisitermes minor, were searched with a portable acoustic emission (AE) device. Depending on cross-sectional size, boards were either searched with a flat sensor that was hot-melt-glued to the wood surface or a subsurface sensor that wasthreaded 20 mm into the...

Ground-penetrating radar: use and misuse

NASA Astrophysics Data System (ADS)

Olhoeft, Gary R.

1999-10-01

Ground penetrating radar (GPR) has been used to explore the subsurface of the earth since 1929. Over the past 70 years, it has been widely used, misused and abused. Use includes agriculture, archaeology, environmental and geotechnical site characterization, minerals, groundwater and permafrost exploration, tunnel, utility, and unexploded ordnance location, dam inspection, and much more. Misuse includes mistaking above ground reflections for subsurface events or mapping things from off to the side as if they were directly below, synthetic aperture processing of dispersive data, minimum phase deconvolution, locating objects smaller than resolution limits of the wavelength in the ground, ignoring Fresnel zone limitations in mapping subsurface structure, processing radar data through seismic software packages without allowing for the differences, mapping the bottom of metal pipes from the top, claiming to see through thousands of feet of sediments, and more. GPR is also being abused as the regulatory environment changes and the radiofrequency spectrum is becoming more crowded by cellular phones, pagers, garage door openers, wireless computer networks, and the like. It is often thought to be a source of interference (though it never is) and it is increasingly interfered with by other radiofrequency transmitters.

Sensitivity of transpiration to subsurface properties: Exploration with a 1-D model

DOE PAGES

Vrettas, Michail D.; Fung, Inez Y.

2017-05-04

The amount of moisture transpired by vegetation is critically tied to the moisture supply accessible to the root zone. In a Mediterranean climate, integrated evapotranspiration (ET) is typically greater in the dry summer when there is an uninterrupted period of high insolation. We present a 1-D model to explore the subsurface factors that may sustain ET through the dry season. The model includes a stochastic parameterization of hydraulic conductivity, root water uptake efficiency, and hydraulic redistribution by plant roots. Model experiments vary the precipitation, the magnitude and seasonality of ET demand, as well as rooting profiles and rooting depths ofmore » the vegetation. The results show that the amount of subsurface moisture remaining at the end of the wet winter is determined by the competition among abundant precipitation input, fast infiltration, and winter ET demand. The weathered bedrock retains math formula of the winter rain and provides a substantial moisture reservoir that may sustain ET of deep-rooted (>8 m) trees through the dry season. A small negative feedback exists in the root zone, where the depletion of moisture by ET decreases hydraulic conductivity and enhances the retention of moisture. Hence, hydraulic redistribution by plant roots is impactful in a dry season, or with a less conductive subsurface. Suggestions for implementing the model in the CESM are discussed.« less

3D numerical modeling of hyporheic exchange processes in fractal riverbed

NASA Astrophysics Data System (ADS)

Lee, A.; Aubeneau, A.

2017-12-01

The subsurface region receiving stream water is known as the hyporheic zone and the flow of water in and out of this zone is called hyporheic exchange. The hyporheic zone is populated by biofilms and is a hotspot for nutrient uptake and contaminant transformation. Traditionally, pumping models predicting the head distribution over the riverbed boundary are used to obtain the velocity field in the subsurface. However, past research has largely overlooked the nonlinearity of the turbulent flow above the bumpy riverbed. The main objective of this research is to investigate the effect of spatial and temporal heterogeneity created by turbulent flow on hyporheic exchange and residence time distribution in fractal channel beds. The 3-D fractal riverbed is created from the power spectrum. Large-Eddy Simulation is used to provide the pressure field over the benthic boundary. Finally, Darcian fluxes in the sub-surface are calculated and hyporheic travel times computed using random walks. Surface and subsurface transport processes are represented explicitly and can be studied in detail. Our results suggest that (1) Eddies and wakes around the dunes force the exchange (2) The bigger the dunes, the greater the influence of turbulence (3) Turbulence induces more exchange than pumping predicts.

High frequency electromagnetic impedance measurements for characterization, monitoring and verification efforts. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, K.H.; Pellerin, L.; Becker, A.

1998-06-01

'Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small due, and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high resolution imaging, accurate measurements are necessary so the field datamore » can be mapped into the space of the subsurface parameters. The authors are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach, known as the magnetotelluric (MT) method at low frequencies. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques. The summary of the work to date is divided into three sections: equipment procurement, instrumentation, and theoretical developments. For most earth materials, the frequency range from 1 to 100 MHz encompasses a very difficult transition zone between the wave propagation of displacement currents and the diffusive behavior of conduction currents. Test equipment, such as signal generators and amplifiers, does not cover the entire range except at great expense. Hence the authors have divided the range of investigation into three sub-ranges: 1--10 MHz, 10--30 MHz, and 30--100 MHz. Results to date are in the lowest frequency range of 1--10 MHz. Even though conduction currents dominate in this range, as in traditional electromagnetic exploration methods, little work has been done by the geophysical community above 500 kHz.'« less

Subsurface Environment Sampler for Improved In Situ Characterization of Subsurface Microbial Communities

NASA Astrophysics Data System (ADS)

Barnhart, E. P.; Ruppert, L. F.; Orem, W. H.; McIntosh, J. C.; Cunningham, A. B.; Fields, M. W.; Hiebert, R.; Hyatt, R.

2016-12-01

There is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by the extraction and transport of fossil fuels. This threat increases the need for improved groundwater monitoring and the ability to predict the extent to which microbial activity may remediate such contamination. The characterization of subsurface microbial communities could provide an ideal biomonitoring tool for the assessment of subsurface contamination due to prokaryotes environmental ubiquity, rapidity of response to environmental perturbation and the important role they play in hydrocarbon degradation and bioremediation. New DNA sequencing technologies provide the opportunity to cost-effectively identify the vast subsurface microbial ecosystem, but use of this new technology is restricted due to issues with sampling. Prior subsurface microbiology studies have relied on core samples that are expensive to obtain hard to collect aseptically and/or ground water samples that do not reflect in situ microbial densities or activities. The development of down-well incubation of sterile sediment with a Diffusive Microbial Sampler (DMS) has emerged as an alternative method to sample subsurface microbial communities that minimizes cost and contamination issues associated with traditional methods. We have designed a Subsurface Environment Sampler with a DMS module that could enable the anaerobic transport of the in situ microbial community from the field for laboratory bioremediation studies. This sampler could provide an inexpensive and standard method for subsurface microbial sampling which would make this tool useful for Federal, State, private and local agencies interested in monitoring contamination or the effectiveness of bioremediation activities in subsurface aquifers.

Environmental Assessment for Selection and Operation of the Proposed Field Research Centers for the Natural and Accelerated Bioremediation Research (NABIR) Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

N /A

2000-04-18

The US Department of Energy (DOE) Office of Biological and Environmental Research (OBER), within the Office of Science (SC), proposes to add a Field Research Center (FRC) component to the existing Natural and Accelerated Bioremediation Research (NABIR) Program. The NABIR Program is a ten-year fundamental research program designed to increase the understanding of fundamental biogeochemical processes that would allow the use of bioremediation approaches for cleaning up DOE's contaminated legacy waste sites. An FRC would be integrated with the existing and future laboratory and field research and would provide a means of examining the fundamental biogeochemical processes that influence bioremediationmore » under controlled small-scale field conditions. The NABIR Program would continue to perform fundamental research that might lead to promising bioremediation technologies that could be demonstrated by other means in the future. For over 50 years, DOE and its predecessor agencies have been responsible for the research, design, and production of nuclear weapons, as well as other energy-related research and development efforts. DOE's weapons production and research activities generated hazardous, mixed, and radioactive waste products. Past disposal practices have led to the contamination of soils, sediments, and groundwater with complex and exotic mixtures of compounds. This contamination and its associated costs and risks represents a major concern to DOE and the public. The high costs, long duration, and technical challenges associated with remediating the subsurface contamination at DOE sites present a significant need for fundamental research in the biological, chemical, and physical sciences that will contribute to new and cost-effective solutions. One possible low-cost approach for remediating the subsurface contamination of DOE sites is through the use of a technology known as bioremediation. Bioremediation has been defined as the use of microorganisms to biodegrade or biotransform hazardous organic contaminants to environmentally safe levels in soils, subsurface materials, water, sludges, and residues.. While bioremediation technology is promising, DOE managers and non-DOE scientists have recognized that the fundamental scientific information needed to develop effective bioremediation technologies for cleanup of the legacy waste sites is lacking in many cases. DOE believes that field-based research is needed to realize the full potential of bioremediation. The Department of Energy faces a unique set of challenges associated with cleaning up waste at its former weapons production and research sites. These sites contain complex mixtures of contaminants in the subsurface, including radioactive compounds. In many cases, the fundamental field-based scientific information needed to develop safe and effective remediation and cleanup technologies is lacking. DOE needs fundamental research on the use of microorganisms and their products to assist DOE in the decontamination and cleanup of its legacy waste sites. The existing NABIR program to-date has focused on fundamental scientific research in the laboratory. Because subsurface hydrologic and geologic conditions at contaminated DOE sites cannot easily be duplicated in a laboratory, however, the DOE needs a field component to permit existing and future laboratory research results to be field-tested on a small scale in a controlled outdoor setting. Such field-testing needs to be conducted under actual legacy waste field conditions representative of those that DOE is most in need of remediating. Ideally, these field conditions should be as representative as practicable of the types of subsurface contamination conditions that resulted from legacy wastes from the nuclear weapons program activities. They should also be representative of the types of hydrologic and geologic conditions that exist across the DOE complex.« less

Induction signals from Callisto's ionosphere and their implications on a possible subsurface ocean

NASA Astrophysics Data System (ADS)

Hartkorn, Oliver; Saur, Joachim

2017-11-01

We investigate whether induction within Callisto's electrically conductive ionosphere can explain observed magnetic fields which have previously been interpreted as evidence of induction in a saline, electrically conductive subsurface ocean. Callisto's ionosphere is subject to the flow of time-periodic magnetized plasma of Jupiter's magnetosphere, which induces electric fields and electric currents in Callisto's electrically conductive ionosphere. We develop a simple analytic model for a first quantitative understanding of the effects of induction in Callisto's ionosphere caused by the interaction with a time-variable magnetic field environment. With this model, we also investigate how the associated ionospheric currents close in the ambient magnetospheric plasma. Based on our model, we find that the anisotropic nature of Callisto's ionospheric conductivity generates an enhancement effect on ionospheric loop currents which are driven by the time-variable magnetic field. This effect is similar to the Cowling channel effect known from Earth's ionosphere. Subsequently, we numerically calculate the expected induced magnetic fields due to Jupiter's time-variable magnetic field in an anisotropic conductive ionosphere and compare our results with the Galileo C-3 and C-9 flybys. We find that induction within Callisto's ionosphere is responsible for a significant part of the observed magnetic fields. Ionospheric induction creates induced magnetic fields to some extent similar as expected from a subsurface water ocean. Depending on currently unknown properties such as Callisto's nightside ionosphere, the existence of layers of "dirty ice" and the details of the plasma interaction, a water ocean might be located much deeper than previously thought or might not exist at all.

Identification and characterization of natural pipe systems in forested tropical soils

NASA Astrophysics Data System (ADS)

Bovi, Renata Cristina; Moreira, Cesar Augusto; Stucchi Boschi, Raquel; Cooper, Miguel

2017-04-01

Erosive processes on soil surface have been well studied and comprehended by several researchers, however little is known about subsurface erosive processes (piping). Piping is a type of subsurface erosion caused by water flowing in the subsurface and is still considered one of the most difficult erosive processes to be studied. Several processes have been considered as resposible for subsurface erosion and their interaction is complex and difficult to be studied separately. Surface investigations on their own may underestimate the erosion processes, due to the possible occurrence of subsurface processes that are not yet exposed on the surface. The network of subsurface processes should also be understood to better control erosion. Conservation practices that focus on water runoff control may be inefficient if the subsurface flow is not considered. In this study, we aimed to identify and characterize subsurface cavities in the field, as well as understand the network of these cavities, by using geophysical methods (electrical tomography). The study area is situated at the Experimental Station of Tupi, state of São Paulo, Brazil. The soil of the area was classified as Hapludults. The area presents several erosive features, ranging from laminar to permanent gullies and subsurface erosions. The geophysical equipment used was the Terrameter LS resistivity meter, manufactured by ABEM Instruments. The method of electrical tomography was efficient to detect collapsed and non-collapsed pipes. The results presented valuable information to detect areas of risk.

Modeling and risk assessment of a 30-Year-old subsurface radioactive-liquid drain field

NASA Astrophysics Data System (ADS)

Dawson, Lon A.; Pohl, Phillip I.

1997-11-01

The contamination from a 30-year-old radioactive liquid drain field was assessed for movement in the subsurface and potential risks to humans. This assessment included determining field concentrations of cesium 137 (137Cs) and other inorganic contaminants and modeling of the flow and transport of the liquid waste that was sent to the drain field. The field investigation detected no contamination deeper than 15 feet (4.6 m) from the bottom of the drain field. Prediction of the water content of the vadose zone showed no saturated conditions for times greater than 10 years after the known infiltration. Sensitivity analysis of the modeling parameters showed the equilibrium sorption coefficient to be the most important factor in predicting the contaminant plumes. Calibration of modeling results with field data gave a 137Cs sorption coefficient that is within the range of values found in the literature. The risk assessment for the site showed that the contamination poses no significant risk to human health.

A seismic search for the paleoshorelines of Lake Otero beneath White Sands Dune Field, New Mexico

NASA Astrophysics Data System (ADS)

Wagner, P. F.; Reece, R.; Ewing, R. C.

2014-12-01

The Tularosa Basin, which now houses White Sands Dune Field, was once occupied by Pleistocene Lake Otero. Several paleoshorelines of Lake Otero have been identified throughout the basin by field surveys and remote sensing using digital elevation models. Up to four shorelines may be buried beneath White Sands Dune Field and it has been posited that the current upwind margin of White Sands coincides with a one of these shorelines. Here we employ a novel geophysical instrument and method to image the subsurface: the seismic land streamer. The land streamer utilizes weighted base plates and one-component vertical geophones in a towed array. With a seisgun acoustic source, we imaged in the Alkali Flats area near the upwind margin, one potential location of paleoshorelines, as well as the Film Lot closer to the center of the dune field. Surfaces in both locations are indurated gypsum playa, which made seismic imaging possible and successful. We collected one SW-NE trending seismic line at each location, which matches the dominant wind and dune migration directions. Based on initial data analysis we find some subsurface structure that may coincide with the paleo lake bed of Lake Otero. The successful demonstration of this new method provides the foundation for an expanded regional subsurface study to image the strata and structure of the Tularosa Basin.

Biofilm formation and potential for iron cycling in serpentinization-influenced groundwater of the Zambales and Coast Range ophiolites.

PubMed

Meyer-Dombard, D'Arcy R; Casar, Caitlin P; Simon, Alexander G; Cardace, Dawn; Schrenk, Matthew O; Arcilla, Carlo A

2018-05-01

Terrestrial serpentinizing systems harbor microbial subsurface life. Passive or active microbially mediated iron transformations at alkaline conditions in deep biosphere serpentinizing ecosystems are understudied. We explore these processes in the Zambales (Philippines) and Coast Range (CA, USA) ophiolites, and associated surface ecosystems by probing the relevance of samples acquired at the surface to in situ, subsurface ecosystems, and the nature of microbe-mineral associations in the subsurface. In this pilot study, we use microcosm experiments and batch culturing directed at iron redox transformations to confirm thermodynamically based predictions that iron transformations may be important in subsurface serpentinizing ecosystems. Biofilms formed on rock cores from the Zambales ophiolite on surface and in-pit associations, confirming that organisms from serpentinizing systems can form biofilms in subsurface environments. Analysis by XPS and FTIR confirmed that enrichment culturing utilizing ferric iron growth substrates produced reduced, magnetic solids containing siderite, spinels, and FeO minerals. Microcosms and enrichment cultures supported organisms whose near relatives participate in iron redox transformations. Further, a potential 'principal' microbial community common to solid samples in serpentinizing systems was identified. These results indicate collectively that iron redox transformations should be more thoroughly and universally considered when assessing the function of terrestrial subsurface ecosystems driven by serpentinization.

Subsurface Stress Fields in FCC Single Crystal Anisotropic Contacts

NASA Technical Reports Server (NTRS)

Arakere, Nagaraj K.; Knudsen, Erik; Swanson, Gregory R.; Duke, Gregory; Ham-Battista, Gilda

2004-01-01

Single crystal superalloy turbine blades used in high pressure turbomachinery are subject to conditions of high temperature, triaxial steady and alternating stresses, fretting stresses in the blade attachment and damper contact locations, and exposure to high-pressure hydrogen. The blades are also subjected to extreme variations in temperature during start-up and shutdown transients. The most prevalent high cycle fatigue (HCF) failure modes observed in these blades during operation include crystallographic crack initiation/propagation on octahedral planes, and non-crystallographic initiation with crystallographic growth. Numerous cases of crack initiation and crack propagation at the blade leading edge tip, blade attachment regions, and damper contact locations have been documented. Understanding crack initiation/propagation under mixed-mode loading conditions is critical for establishing a systematic procedure for evaluating HCF life of single crystal turbine blades. This paper presents analytical and numerical techniques for evaluating two and three dimensional subsurface stress fields in anisotropic contacts. The subsurface stress results are required for evaluating contact fatigue life at damper contacts and dovetail attachment regions in single crystal nickel-base superalloy turbine blades. An analytical procedure is presented for evaluating the subsurface stresses in the elastic half-space, based on the adaptation of a stress function method outlined by Lekhnitskii. Numerical results are presented for cylindrical and spherical anisotropic contacts, using finite element analysis (FEA). Effects of crystal orientation on stress response and fatigue life are examined. Obtaining accurate subsurface stress results for anisotropic single crystal contact problems require extremely refined three-dimensional (3-D) finite element grids, especially in the edge of contact region. Obtaining resolved shear stresses (RSS) on the principal slip planes also involves considerable post-processing work. For these reasons it is very advantageous to develop analytical solution schemes for subsurface stresses, whenever possible.

Long-Term Hydrologic Impacts of Controlled Drainage Using DRAINMOD

NASA Astrophysics Data System (ADS)

Saadat, S.; Bowling, L. C.; Frankenberger, J.

2017-12-01

Controlled drainage is a management strategy designed to mitigate water quality issues caused by subsurface drainage but it may increase surface ponding and runoff. To improve controlled drainage system management, a long-term and broader study is needed that goes beyond the experimental studies. Therefore, the goal of this study was to parametrize the DRAINMOD field-scale, hydrologic model for the Davis Purdue Agricultural Center located in Eastern Indiana and to predict the subsurface drain flow and surface runoff and ponding at this research site. The Green-Ampt equation was used to characterize the infiltration, and digital elevation models (DEMs) were used to estimate the maximum depressional storage as the surface ponding parameter inputs to DRAINMOD. Hydraulic conductivity was estimated using the Hooghoudt equation and the measured drain flow and water table depths. Other model inputs were either estimated or taken from the measurements. The DRAINMOD model was calibrated and validated by comparing model predictions of subsurface drainage and water table depths with field observations from 2012 to 2016. Simulations based on the DRAINMOD model can increase understanding of the environmental and hydrological effects over a broader temporal and spatial scale than is possible using field-scale data and this is useful for developing management recommendations for water resources at field and watershed scales.

UK Astrobiology : Vanguard: a new development in experimental astrobiology

NASA Astrophysics Data System (ADS)

Ellery, Alex; Wynn-Williams, David

2002-04-01

Alex Ellery and David Wynn-Williams propose a new UK astrobiology project, in which a micro-rover would deploy ground-penetrating moles to burrow into the Martian subsurface. One of the linchpins of the UK's contribution to the burgeoning field of astrobiology is the Beagle 2 mission, due to fly to Mars in 2003 on the Mars Express bus. Given that NASA has declared its intention to focus on ``whole planet'' geological investigation in its future Mars missions, beginning with the Mars Exploration Rovers which are due to fly in 2003/2004, the UK is well placed to consider post-Beagle 2 astrobiology-focused Mars missions to ensure its leadership in the future in astrobiology. In this paper we present such a proposal - Vanguard.

Discriminative Random Field Models for Subsurface Contamination Uncertainty Quantification

NASA Astrophysics Data System (ADS)

Arshadi, M.; Abriola, L. M.; Miller, E. L.; De Paolis Kaluza, C.

2017-12-01

Application of flow and transport simulators for prediction of the release, entrapment, and persistence of dense non-aqueous phase liquids (DNAPLs) and associated contaminant plumes is a computationally intensive process that requires specification of a large number of material properties and hydrologic/chemical parameters. Given its computational burden, this direct simulation approach is particularly ill-suited for quantifying both the expected performance and uncertainty associated with candidate remediation strategies under real field conditions. Prediction uncertainties primarily arise from limited information about contaminant mass distributions, as well as the spatial distribution of subsurface hydrologic properties. Application of direct simulation to quantify uncertainty would, thus, typically require simulating multiphase flow and transport for a large number of permeability and release scenarios to collect statistics associated with remedial effectiveness, a computationally prohibitive process. The primary objective of this work is to develop and demonstrate a methodology that employs measured field data to produce equi-probable stochastic representations of a subsurface source zone that capture the spatial distribution and uncertainty associated with key features that control remediation performance (i.e., permeability and contamination mass). Here we employ probabilistic models known as discriminative random fields (DRFs) to synthesize stochastic realizations of initial mass distributions consistent with known, and typically limited, site characterization data. Using a limited number of full scale simulations as training data, a statistical model is developed for predicting the distribution of contaminant mass (e.g., DNAPL saturation and aqueous concentration) across a heterogeneous domain. Monte-Carlo sampling methods are then employed, in conjunction with the trained statistical model, to generate realizations conditioned on measured borehole data. Performance of the statistical model is illustrated through comparisons of generated realizations with the `true' numerical simulations. Finally, we demonstrate how these realizations can be used to determine statistically optimal locations for further interrogation of the subsurface.

Subsurface Tectonics and Pingos of Northern Alaska

NASA Astrophysics Data System (ADS)

Skirvin, S.; Casavant, R.; Burr, D.

2008-12-01

We describe preliminary results of a two-phase study that investigated links between subsurface structural and stratigraphic controls, and distribution of hydrostatic pingos on the central coastal plain of Arctic Alaska. Our 2300 km2 study area is underlain by a complete petroleum system that supports gas, oil and water production from 3 of the largest oil fields in North America. In addition, gas hydrate deposits exist in this area within and just below the permafrost interval at depths of 600 to 1800 feet below sea level. Phase 1 of the study compared locations of subsurface faults and pingos for evidence of linkages between faulting and pingo genesis and distribution. Several hundred discrete fault features were digitized from published data and georeferenced in a GIS database. Fault types were determined by geometry and sense of slip derived from well log and seismic maps. More than 200 pingos and surface sediment type associated with their locations were digitized from regional surficial geology maps within an area that included wire line and seismic data coverage. Beneath the pingos lies an assemblage of high-angle normal and transtensional faults that trend NNE and NW; subsidiary trends are EW and NNW. Quaternary fault reactivation is evidenced by faults that displaced strata at depths exceeding 3000 meters below sea level and intersect near-surface units. Unpublished seismic images and cross-section analysis support this interpretation. Kinematics and distribution of reactivated faults are linked to polyphase deformational history of the region that includes Mesozoic rift events, succeeded by crustal shortening and uplift of the Brooks Range to the south, and differential subsidence and segmentation of a related foreland basin margin beneath the study area. Upward fluid migration, a normal process in basin formation and fault reactivation, may play yet unrecognized roles in the genesis (e.g. fluid charging) of pingos and groundwater hydrology. Preliminary analysis shows that more than half the pingos occur within 150 m of the vertical projections of subsurface fault plane traces. In a previous, unpublished geostatistical study, comparison of pingo and random locations indicated a non-random NE-trending alignment of pingos. This trend in particular matches the dominant orientation of fault sets that are linked to the most recent tectonic deformation of the region. A concurrent Phase 2 of the study examines the potential role of near-surface stratigraphic units in regard to both pingos and faults. Both surface and subsurface coarse-grained deposits across the region are often controlled by fault structures; this study is the first to assess any relationship between reservoir rocks and pingo locations. Cross-sections were constructed from well log data to depths of 100 meters. Subsurface elements were compared with surface features. Although some studies have linked fine-grained surface sediments with pingo occurrence, our analysis hints that coarse-grained sediments underlie pingos and may be related to near-surface fluid transmissivity, as suggested by other researchers. We also investigated pingo occurrence in relationship to upthrown or downthrown fault blocks that vary in the degree of deformation and fluid transmission. Results will guide a proposed pingo drilling project to test linkages between pingos, subsurface geology, hydrology, and petroleum systems. Findings from this study could aid research and planning for field exploration of similar settings on Earth and Mars.

Geophysical Investigation of the Lake City Fault Zone, Surprise Valley, California, and Implications for Geothermal Circulation

NASA Astrophysics Data System (ADS)

McPhee, D. K.; Glen, J. M.; Egger, A. E.; Chuchel, B. A.

2009-12-01

New audiomagnetotelluric (AMT), gravity, and magnetic data were collected in Surprise Valley, northwestern Basin and Range, in order to investigate the role that the Lake City Fault Zone (LCFZ) may play in controlling geothermal circulation in the area. Surprise Valley hosts an extensional geothermal system currently undergoing exploration for development on several scales. The focus of much of that exploration has been the LCFZ, a set of NW-SE-trending structures that has been suggested on the basis of (1) low-relief scarps in the NW portion of the zone, (2) dissolved mineral-rich groundwater chemistry along its length, and (3) parallelism with a strong regional fabric that includes the Brothers Fault Zone. The LCFZ extends across the valley at a topographic high, intersecting the N-S-trending basin-bounding faults where major hot springs occur. This relationship suggests that the LCFZ may be a zone of permeability for flow of hydrothermal fluids. Previous potential field data indicate that there is no vertical offset along this fault zone, and little signature at all in either the gravity or magnetic data; along with the lack of surface expression along most of its length, the subsurface geometry of the LCFZ and its influence on geothermal fluid circulation remains enigmatic. The LCFZ therefore provides an ideal opportunity to utilize AMT data, which measures subsurface resistivity and therefore - unlike potential field data - is highly sensitive to the presence of saline fluids. AMT data and additional gravity and magnetic data were collected in 2009 along 3 profiles perpendicular to the LCFZ in order to define the subsurface geometry and conductivity of the fault zone down to depths of ~ 500 m. AMT soundings were collected using the Geometrics Stratagem EH4 system, a four channel, natural and controlled-source tensor system recording in the range of 10 to 92,000 Hz. To augment the low signal in the natural field a transmitter of two horizontal-magnetic dipoles was used from 800 to 56,000 Hz. One profile extends within 200 m of hot springs and fault scarps near the northwestern end of the LCFZ. There, preliminary data show low resistivities (< 5 ohm-m) at stations closest to the hot springs suggesting that the data are sensitive to high concentrations of salts characteristic of geothermal fluids in the area. Two additional profiles extend across the LCFZ further to the southeast where it is at its widest and most diffuse. Profiles were ~ 3 km-long with station spacing of ~ 200 - 400 m, and data were recorded in a coordinate system parallel to and perpendicular to the regional geologic-strike of the LCFZ. Two-dimensional (2D) inverse models were computed using the conjugate gradient, finite-difference method of Rodi and Mackie (2001). In addition to AMT data, ground magnetic and gravity data were collected along the AMT profiles. These data, combined with the 2D resistivity models, will be used to image the LCFZ at depth and determine whether it is a single through-going fracture zone that potentially hosts hydrothermal fluids within the shallow (< 1km) subsurface or whether it is simply a set of unrelated features with little or no geophysical expression.

Evidence for a climate-induced ecohydrological state shift in wetland ecosystems of the southern Prairie Pothole Region

USGS Publications Warehouse

McKenna, Owen; Mushet, David M.; Rosenberry, Donald O.; LaBaugh, James W.

2017-01-01

Changing magnitude, frequency, and timing of precipitation can influence aquatic-system hydrological, geochemical, and biological processes, in some cases resulting in system-wide shifts to an alternate state. Since the early 1990s, the southern Prairie Pothole Region has been subjected to an extended period of increased wetness resulting in marked changes to aquatic systems defining this region. We explored numerous lines of evidence to identify: (1) how the recent wet period compared to historical variability, (2) hydrological, geochemical, and biological responses, and (3) how these responses might represent a state shift in the region’s wetland ecosystems. We analyzed long-term climate records and compared how different hydrological variables responded in this wet period compared to decades before the observed shift. Additionally, we used multi-decadal records of waterfowl population and subsurface tile drain records to explore wildlife and human responses to a shifting climate. Since 1993, a novel precipitation regime corresponded with increased pond numbers, ponded-water depths, lake levels, stream flows, groundwater heights, soil-moisture, waterfowl populations, and installation of subsurface tile drains in agricultural fields. These observed changes reflect an alteration in water storage and movement across the landscape that in turn has altered solute sources and concentrations of prairie-pothole wetlands and has increased pond permanence. Combined, these changes represent significant evidence for a state shift in the ecohydrological functioning of the region’s wetland ecosystems, a shift that may require a significant refinement of the previously developed “wetland continuum” concept.

Sampling surface and subsurface particle-size distributions in wadable gravel-and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring

Treesearch

Kristin Bunte; Steven R. Abt

2001-01-01

This document provides guidance for sampling surface and subsurface sediment from wadable gravel-and cobble-bed streams. After a short introduction to streams types and classifications in gravel-bed rivers, the document explains the field and laboratory measurement of particle sizes and the statistical analysis of particle-size distributions. Analysis of particle...

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Long-term electrical resistivity monitoring of recharge-induced contaminant plume behavior.

PubMed

Gasperikova, Erika; Hubbard, Susan S; Watson, David B; Baker, Gregory S; Peterson, John E; Kowalsky, Michael B; Smith, Meagan; Brooks, Scott

2012-11-01

Geophysical measurements, and electrical resistivity tomography (ERT) data in particular, are sensitive to properties that are related (directly or indirectly) to hydrological processes. The challenge is in extracting information from geophysical data at a relevant scale that can be used to gain insight about subsurface behavior and to parameterize or validate flow and transport models. Here, we consider the use of ERT data for examining the impact of recharge on subsurface contamination at the S-3 ponds of the Oak Ridge Integrated Field Research Challenge (IFRC) site in Tennessee. A large dataset of time-lapse cross-well and surface ERT data, collected at the site over a period of 12 months, is used to study time variations in resistivity due to changes in total dissolved solids (primarily nitrate). The electrical resistivity distributions recovered from cross-well and surface ERT data agrees well, and both of these datasets can be used to interpret spatiotemporal variations in subsurface nitrate concentrations due to rainfall, although the sensitivity of the electrical resistivity response to dilution varies with nitrate concentration. Using the time-lapse surface ERT data interpreted in terms of nitrate concentrations, we find that the subsurface nitrate concentration at this site varies as a function of spatial position, episodic heavy rainstorms (versus seasonal and annual fluctuations), and antecedent rainfall history. These results suggest that the surface ERT monitoring approach is potentially useful for examining subsurface plume responses to recharge over field-relevant scales. Published by Elsevier B.V.

Study of Geological Analogues for Understanding the Radar Sounder Response of the RIME Targets

NASA Astrophysics Data System (ADS)

Thakur, S.; Bruzzone, L.

2017-12-01

Radar for Icy Moon Exploration (RIME), the radar sounder onboard the Jupiter Icy Moons Explorer (JUICE), is aimed at characterizing the ice shells of the Jovian moons - Ganymede, Europa and Callisto. RIME is optimized to operate at 9 MHz central frequency with bandwidth of 1 MHz and 2.7 MHz to achieve a penetration depth up to 9 km through ice. We have developed an approach to the definition of a database of simulated RIME radargrams by leveraging the data available from airborne and orbital radar sounder acquisitions over geological analogues of the expected icy moon features. These simulated radargrams are obtained by merging real radar sounder data with models of the subsurface of the Jupiter icy moons. They will be useful for geological interpretation of the RIME radargrams and for better predicting the performance of RIME. The database will also be useful in developing pre-processing and automatic feature extraction algorithms to support data analysis during the mission phase of RIME. Prior to the JUICE mission exploring the Jovian satellites with RIME, there exist radar sounders such as SHARAD (onboard MRO) and MARSIS (onboard MEX) probing Mars, the LRS (onboard SELENE) probing the Moon, and many airborne sounders probing the polar regions of Earth. Analogues have been identified in these places based on similarity in geo-morphological expression. Moreover, other analogues have been identified on the Earth for possible dedicated acquisition campaigns before the RIME operations. By assuming that the subsurface structure of the RIME targets is approximately represented in the analogue radargrams, the difference in composition is accounted for by imposing different dielectric and subsurface attenuation models. The RIME radargrams are simulated from the analogue radargrams using the radar equation and the RIME processing chain and accounting for different possible scenarios in terms of subsurface structure, dielectric properties and instrument parameters. For cross-validation, the database is compared with radargrams simulated from the analysis of radio wave propagation through geo-electrical models representing the subsurface hypotheses for the RIME targets.

Subsurface Hydrologic Processes Revealed by Time-lapse GPR in Two Contrasting Soils in the Shale Hills CZO

NASA Astrophysics Data System (ADS)

Guo, L.; Lin, H.; Nyquist, J.; Toran, L.; Mount, G.

2017-12-01

Linking subsurface structures to their functions in determining hydrologic processes, such as soil moisture dynamics, subsurface flow patterns, and discharge behaviours, is a key to understanding and modelling hydrological systems. Geophysical techniques provide a non-invasive approach to investigate this form-function dualism of subsurface hydrology at the field scale, because they are effective in visualizing subsurface structure and monitoring the distribution of water. In this study, we used time-lapse ground-penetrating radar (GPR) to compare the hydrologic responses of two contrasting soils in the Shale Hills Critical Zone Observatory. By integrating time-lapse GPR with artificial water injection, we observed distinct flow patterns in the two soils: 1) in the deep Rushtown soil (over 1.5 m depth to bedrock) located in a concave hillslope, a lateral preferential flow network extending as far as 2 m downslope was identified above a less permeable layer and via a series of connected macropores; whereas 2) in the shallow Weikert soil ( 0.3 m depth to saprock) located in a planar hillslope, vertical infiltration into the permeable fractured shale dominated the flow field, while the development of lateral preferential flow along the hillslope was restrained. At the Weikert soil site, the addition of brilliant blue dye to the water injection followed by in situ excavation supported GPR interpretation that only limited lateral preferential flow formed along the soil-saprock interface. Moreover, seasonally repeated GPR surveys indicated different patterns of profile moisture distribution in the two soils that in comparison with the dry season, a dense layer within the BC horizon in the deep Rushtown soil prevented vertical infiltration in the wet season, leading to the accumulation of soil moisture above this layer; whereas, in the shallow Weikert soil, water infiltrated into saprock in wet seasons, building up water storage within the fractured bedrock (i.e., the rock moisture). Results of this study demonstrated the strong interplay between soil structures and subsurface hydrologic behaviors, and time-lapse GPR is an effective method to establish such a relationship under the field conditions.

Forward modeling to investigate inversion artifacts resulting from time-lapse electrical resistivity tomography during rainfall simulations

NASA Astrophysics Data System (ADS)

Carey, Austin M.; Paige, Ginger B.; Carr, Bradley J.; Dogan, Mine

2017-10-01

Time-lapse electrical resistivity tomography (ERT) is commonly used as a minimally invasive tool to study infiltration processes. In 2014, we conducted field studies coupling variable intensity rainfall simulation with high-resolution ERT to study the real-time partitioning of rainfall into surface and subsurface response. The significant contrast in resistivity in the subsurface from large changes in subsurface moisture resulted in artifacts during the inversion process of the time-lapse ERT data collected using a dipole-dipole electrode array. These artifacts, which are not representative of real subsurface moisture dynamics, have been shown to arise during time-lapse inversion of ERT data and may be subject to misinterpretation. Forward modeling of the infiltration process post field experiments using a two-layer system (saprolite overlain by a soil layer) was used to generate synthetic datasets. The synthetic data were used to investigate the influence of both changes in volumetric moisture content and electrode configuration on the development of the artifacts identified in the field datasets. For the dipole-dipole array, we found that a decrease in the resistivity of the bottom layer by 67% resulted in a 50% reduction in artifact development. Artifacts for the seven additional array configurations tested, ranged from a 19% increase in artifact development (using an extended dipole-dipole array) to as much as a 96% decrease in artifact development (using a wenner-alpha array), compared to that of the dipole-dipole array. Moreover, these arrays varied in their ability to accurately delineate the infiltration front. Model results showed that the modified pole-dipole array was able to accurately image the infiltration zone and presented fewer artifacts for our experiments. In this study, we identify an optimal array type for imaging rainfall-infiltration dynamics that reduces artifacts. The influence of moisture contrast between the infiltrating water and the bulk subsurface material was characterized and shown to be a major factor in contributing to artifact development. Through forward modeling, this study highlights the importance of considering array type and subsurface moisture conditions when using time-lapse resistivity to obtain reliable estimates of vadose zone flow processes during rainfall-infiltration events.

Integration of multi-source and multi-scale datasets for 3D structural modeling for subsurface exploration targeting, Luanchuan Mo-polymetallic district, China

NASA Astrophysics Data System (ADS)

Wang, Gongwen; Ma, Zhenbo; Li, Ruixi; Song, Yaowu; Qu, Jianan; Zhang, Shouting; Yan, Changhai; Han, Jiangwei

2017-04-01

In this paper, multi-source (geophysical, geochemical, geological and remote sensing) datasets were used to construct multi-scale (district-, deposit-, and orebody-scale) 3D geological models and extract 3D exploration criteria for subsurface Mo-polymetallic exploration targeting in the Luanchuan district in China. The results indicate that (i) a series of region-/district-scale NW-trending thrusts controlled main Mo-polymetallic forming, and they were formed by regional Indosinian Qinling orogenic events, the secondary NW-trending district-scale folds and NE-trending faults and the intrusive stock structure are produced based on thrust structure in Caledonian-Indosinian orogenic events; they are ore-bearing zones and ore-forming structures; (ii) the NW-trending district-scale and NE-trending deposit-scale normal faults were crossed and controlled by the Jurassic granite stocks in 3D space, they are associated with the magma-skarn Mo polymetallic mineralization (the 3D buffer distance of ore-forming granite stocks is 600 m) and the NW-trending hydrothermal Pb-Zn deposits which are surrounded by the Jurassic granite stocks and constrained by NW-trending or NE-trending faults (the 3D buffer distance of ore-forming fault is 700 m); and (iii) nine Mo polymetallic and four Pb-Zn targets were identified in the subsurface of the Luanchuan district.

Subsurface Hydrology: Data Integration for Properties and Processes

NASA Astrophysics Data System (ADS)

Hyndman, David W.; Day-Lewis, Frederick D.; Singha, Kamini

Groundwater is a critical resource and the PrinciPal source of drinking water for over 1.5 billion people. In 2001, the National Research Council cited as a "grand challenge" our need to understand the processes that control water movement in the subsurface. This volume faces that challenge in terms of data integration between complex, multi-scale hydrologie processes, and their links to other physical, chemical, and biological processes at multiple scales. Subsurface Hydrology: Data Integration for Properties and Processes presents the current state of the science in four aspects: • Approaches to hydrologie data integration • Data integration for characterization of hydrologie properties • Data integration for understanding hydrologie processes • Meta-analysis of current interpretations Scientists and researchers in the field, the laboratory, and the classroom will find this work an important resource in advancing our understanding of subsurface water movement.

Visualization of geologic stress perturbations using Mohr diagrams.

PubMed

Crossno, Patricia; Rogers, David H; Brannon, Rebecca M; Coblentz, David; Fredrich, Joanne T

2005-01-01

Huge salt formations, trapping large untapped oil and gas reservoirs, lie in the deepwater region of the Gulf of Mexico. Drilling in this region is high-risk and drilling failures have led to well abandonments, with each costing tens of millions of dollars. Salt tectonics plays a central role in these failures. To explore the geomechanical interactions between salt and the surrounding sand and shale formations, scientists have simulated the stresses in and around salt diapirs in the Gulf of Mexico using nonlinear finite element geomechanical modeling. In this paper, we describe novel techniques developed to visualize the simulated subsurface stress field. We present an adaptation of the Mohr diagram, a traditional paper-and-pencil graphical method long used by the material mechanics community for estimating coordinate transformations for stress tensors, as a new tensor glyph for dynamically exploring tensor variables within three-dimensional finite element models. This interactive glyph can be used as either a probe or a filter through brushing and linking.

Effect of irrigation techniques and strategies on water footprint of growing crops

NASA Astrophysics Data System (ADS)

Chukalla, A. D.; Krol, M. S.; Hoekstra, A. Y. Y.

2014-12-01

Reducing the water footprint (WF) of growing crops, the largest water user and a significant contributor to the WF of many consumer products, plays a significant role in integrated and sustainable water management. The water footprint for growing crop is accounted by relating the crop yield with the corresponding consumptive water use (CWU), which both can be adjusted by measures that affect the crop growth and root-zone soil water balance. This study explored the scope for reducing the water footprint of irrigated crops by experimenting set of field level technical and managerial measures: (i) irrigation technologies (Furrow, sprinkler, drip and sub-surface drip), (ii) irrigation strategies (full and a range of sustained and controlled deficit) and (iii) field management options (zero, organic and synthetic mulching). Ranges of cases were also considered: (a) Arid and semi-arid environment (b) Loam and Sandy-loam soil types and (c) for Potato, Wheat and Maize crops; under (c) wet, normal and dry years. AquaCrop, the water driven crop growth and soil water balance model, offered the opportunity to systematically experiment these measures on water consumption and yield. Further, the green and blue water footprints of growing crop corresponding to each measure were computed by separating the root zone fluxes of the AquaCrop output into the green and blue soil water stocks and their corresponding fluxes. Results showed that in arid environment reduction in irrigation supply, CWU and WF up to 300 mm, 80 mm and 75 m3/tonne respectively can be achieved for Maize by a combination of organic mulching and drip technology with controlled deficit irrigation strategies (10-20-30-40% deficit with reference to the full irrigation requirement). These reductions come with a yield drop of 0.54 tonne/ha. In the same environment under the absence of mulching practice, the sub-surface drip perform better in reducing CWU and WF of irrigated crops followed by drip and furrow irrigation technique. This rank though changes in non-moisture limiting condition (wet year) drip performing better in reducing the WF of growing crops than sub-surface drip. It was observed that with all range of irrigation techniques, strategies and field management practices there is more room in reducing the WF of growing crops in loam than sandy-loam soil.

Mars Exploration Rover surface operations: driving spirit at Gusev Crater

NASA Technical Reports Server (NTRS)

Leger, Chris; Trebi-Ollennu, Ashitey; Wright, John; Maxwell, Scott; Bonitz, Bob; Biesiadecki, Jeff; Hartman, Frank; Cooper, Brian; Baumgartner, Eric; Maimone, Mark

2005-01-01

Spirit is one of two rovers, that landed on Mars in January 2004 as part of NASA's Mars Exploration Rovers mission. Since then, Spirit has traveled over 4 kilometers accross the Martian surface while investigating rocks and soils, digging trenches to examine the subsurface environment, and climbing hills to reach outcrops of bedrock.

A coupled subsurface-boundary layer model of water on Mars

NASA Astrophysics Data System (ADS)

Zent, A. P.; Haberle, R. M.; Houben, H. C.; Jakosky, B. M.

1993-02-01

A 1D numerical model of the exchange of H2O between the atmosphere and subsurface of Mars through the PBL is employed to explore the mechanisms of H2O exchange and to elucidate the role played by the regolith in the local H2O budget. The atmospheric model includes effects of Coriolis, pressure gradient, and frictional forces for momentum: radiation, sensible heat flux, and advection for heat. It is suggested that in most cases, the flux through the Martian surface reverses twice in the course of each sol. The effects of surface albedo, thermal inertia, solar declination, atmospheric optical depth, and regolith pore structure are explored. It is proposed that higher thermal inertia forces more H2O into the atmosphere because the regolith is warmer at depth.

Impacts of Land-applied Wastes from Concentrated Animal Feeding Operations on Aquatic Organisms

EPA Science Inventory

Midwest agricultural fields typically have subsurface tile-drain networks that facilitate transport of excess water from fields to a ditch network system, which can contain sediments, nutrients and pesticides as well as hormones from fields fertilized with manure and associated l...

Heat pulse probe measurements of soil water evaporation in a corn field

USDA-ARS?s Scientific Manuscript database

Latent heat fluxes from cropped fields consist of soil water evaporation and plant transpiration. It is difficult to accurately separate evapotranspiration into evaporation and transpiration. Heat pulse probes have been used to measure bare field subsurface soil water evaporation, however, the appl...

Microbial community assembly and evolution in subseafloor sediment.

PubMed

Starnawski, Piotr; Bataillon, Thomas; Ettema, Thijs J G; Jochum, Lara M; Schreiber, Lars; Chen, Xihan; Lever, Mark A; Polz, Martin F; Jørgensen, Bo B; Schramm, Andreas; Kjeldsen, Kasper U

2017-03-14

Bacterial and archaeal communities inhabiting the subsurface seabed live under strong energy limitation and have growth rates that are orders of magnitude slower than laboratory-grown cultures. It is not understood how subsurface microbial communities are assembled and whether populations undergo adaptive evolution or accumulate mutations as a result of impaired DNA repair under such energy-limited conditions. Here we use amplicon sequencing to explore changes of microbial communities during burial and isolation from the surface to the >5,000-y-old subsurface of marine sediment and identify a small core set of mostly uncultured bacteria and archaea that is present throughout the sediment column. These persisting populations constitute a small fraction of the entire community at the surface but become predominant in the subsurface. We followed patterns of genome diversity with depth in four dominant lineages of the persisting populations by mapping metagenomic sequence reads onto single-cell genomes. Nucleotide sequence diversity was uniformly low and did not change with age and depth of the sediment. Likewise, there was no detectable change in mutation rates and efficacy of selection. Our results indicate that subsurface microbial communities predominantly assemble by selective survival of taxa able to persist under extreme energy limitation.

Geophysical characterization of the role of fault and fracture systems for recharging groundwater aquifers from surface water of Lake Nasser

NASA Astrophysics Data System (ADS)

Mansour, Khamis; Omar, Khaled; Ali, Kamal; Abdel Zaher, Mohamed

2018-06-01

The role of the fracture system is important for enhancing the recharge or discharge of fluids in the subsurface reservoir. The Lake Nasser is consider one of the largest artificial lakes all over the world and contains huge bulk of storage water. In this study, the influence of fracture zones on subsurface fluid flow in groundwater reservoirs is investigated using geophysical techniques including seismicity, geoelectric and gravity data. These data have been utilized for exploring structural structure in south west Lake Nasser, and subsurface discontinuities (joints or faults) notwithstanding its related fracture systems. Seismicity investigation gave us the comprehension of the dynamic geological structure sets and proposing the main recharging paths for the Nubian aquifer from Lake Nasser surface water. Processing and modelling of aerogravity data show that the greater thickness of sedimentary cover (700 m) is located eastward and northward while basement outcrops occur at Umm Shaghir and Al Asr areas. Sixty-nine vertical electrical soundings (VES's) were used to delineate the subsurface geoelectric layers along eight profiles that help to realize the subsurface geological structure behind the hydrogeological conditions of the studied area.

Remote sensing capacity of Raman spectroscopy in identification of mineral and organic constituents

NASA Astrophysics Data System (ADS)

Chen, Bin; Stoker, Carol; Cabrol, Nathalie; McKay, Christopher P.

2007-09-01

We present design, integration and test results for a field Raman spectrometer science payload, integrated into the Mars Analog Research and Technology (MARTE) drilling platform. During the drilling operation, the subsurface Raman spectroscopy inspection system has obtained signatures of organic and mineral compositions. We also performed ground truth studies using both this field unit and a laboratory micro Raman spectrometer equipped with multiple laser excitation wavelengths on series of field samples including Mojave rocks, Laguna Verde salty sediment and Rio Tinto topsoil. We have evaluated laser excitation conditions and optical probe designs for further improvement. We have demonstrated promising potential for Raman spectroscopy as a non-destructive in situ, high throughput, subsurface detection technique, as well as a desirable active remote sensing tool for future planetary and space missions.

Ranging methods for developing wellbores in subsurface formations

DOEpatents

MacDonald, Duncan [Houston, TX

2011-09-06

A method for forming two or more wellbores in a subsurface formation includes forming a first wellbore in the formation. A second wellbore is directionally drilled in a selected relationship relative to the first wellbore. At least one magnetic field is provided in the second wellbore using one or more magnets in the second wellbore located on a drilling string used to drill the second wellbore. At least one magnetic field is sensed in the first wellbore using at least two sensors in the first wellbore as the magnetic field passes by the at least two sensors while the second wellbore is being drilled. A position of the second wellbore is continuously assessed relative to the first wellbore using the sensed magnetic field. The direction of drilling of the second wellbore is adjusted so that the second wellbore remains in the selected relationship relative to the first wellbore.

Method of Mapping Anomalies in Homogenous Material

NASA Technical Reports Server (NTRS)

Taylor, Bryant D. (Inventor); Woodard, Stanley E. (Inventor)

2016-01-01

An electrical conductor and antenna are positioned in a fixed relationship to one another. Relative lateral movement is generated between the electrical conductor and a homogenous material while maintaining the electrical conductor at a fixed distance from the homogenous material. The antenna supplies a time-varying magnetic field that causes the electrical conductor to resonate and generate harmonic electric and magnetic field responses. Disruptions in at least one of the electric and magnetic field responses during this lateral movement are indicative of a lateral location of a subsurface anomaly. Next, relative out-of-plane movement is generated between the electrical conductor and the homogenous material in the vicinity of the anomaly's lateral location. Disruptions in at least one of the electric and magnetic field responses during this out-of-plane movement are indicative of a depth location of the subsurface anomaly. A recording of the disruptions provides a mapping of the anomaly.

WISDOM GPR investigations in a Mars-analog environment during the SAFER rover operation simulation

NASA Astrophysics Data System (ADS)

Dorizon, S.; Ciarletti, V.; Plettemeier, D.; Vieau, A.-J.; Benedix, W.-S.; Mütze, M.; Hassen-Kodja, R.; Humeau, O.

2014-04-01

The WISDOM (Water Ice Subsurface Deposits Observations on Mars) Ground Penetrating Radar has been selected to be onboard the ExoMars 2018 rover mission [1]. This instrument will investigate the Martian shallow subsurface and provide the geological context of the mission, by characterizing the subsurface in terms of structure, stratigraphy and potential buried objects. It will also quantify the geoelectrical properties of the medium, which are directly related to its nature, its water or salts content and its hardness [2]. WISDOM data will provide important clues to guide the drilling operations to location of potential exobiological interest. A prototype available in LATMOS, France, is currently tested in a wide range of natural environments. In this context, the WISDOM team participated in the SAFER (Sample Acquisition Field Experiment with a Rover) field trial that occurred from 7th to 13th October 2013 in the Atacama Desert, Chile. Designed to gather together scientists and engineers in a context of a real Martian mission with a rover, the SAFER trial was the opportunity to use three onboard ExoMars instruments, namely CLUPI (Close- UP Imager), PANCAM (Panoramic Camera) and WISDOM, to investigate the chosen area. We present the results derived from WISDOM data acquired over the SAFER trial site to characterize the shallow subsurface of the area.

Integrated geophysical methods for geotechnical subsurface investigations : final report.

DOT National Transportation Integrated Search

2006-01-01

This report summarizes the New Hampshire Department of Transportations (NHDOTs) investigation of : geophysical techniques to supplement conventional test borings and other explorations on transportation projects. : The Departments geotechnic...

Radar Imaging of Europa's Subsurface Properties and Processes: The View from Earth

NASA Astrophysics Data System (ADS)

Blankenship, D. D.; Moore, W. B.; Young, D. A.; Peters, M. E.

2007-12-01

A primary objective of future Europa studies will be to characterize the distribution of shallow subsurface water as well as to identify any ice-ocean interface. Another objective will be to understand the formation of surface and subsurface features associated with interchange processes between any ocean and the surface. Achieving these objectives will require either direct or inferred knowledge of the position of any ice/water interfaces as well as any brine or layer pockets. We will review the hypothesized processes that control the thermal, compositional and structural (TCS) properties, and therefore the dielectric character, of the subsurface of Europa's icy shell. Our approach will be to extract the TCS properties for various subsurface processes thought to control the formation of major surface (e.g., ridges/bands, lenticulae, chaos, cratering...) and subsurface (e.g., rigid shell eutectics, diapirs, accretionary lenses ...) features on Europa. We will then assess the spectrum of analog processes and TCS properties represented by Earth's cryosphere including both Arctic and Antarctic ice sheets, ice shelves and valley glaciers. There are few complete analogs over the full TCS space but, because of the wide range of ice thickness, impurities and strain rates for Earth's cryosphere, there are many more analogs than many Earth and planetary researchers might imagine for significant portions of this space (e.g., bottom crevasses, marine ice shelf/subglacial lake accretion, surging polythermal glaciers...).Our ultimate objective is to use these Earth analog studies to define the radar imaging approach for Europa's subsurface that will be most useful for supporting/refuting the hypotheses for the formation of major surface/subsurface features as well as for "pure" exploration of Europa's icy shell and its interface with the underlying ocean.

Fractional Diffusion Analysis of the Electromagnetic Field In Fractured Media Part II: 2.5-D Approach

NASA Astrophysics Data System (ADS)

Ge, J.; Everett, M. E.; Weiss, C. J.

2012-12-01

A 2.5D finite difference (FD) frequency-domain modeling algorithm based on the theory of fractional diffusion of electromagnetic (EM) fields generated by a loop source lying above a fractured geological medium is addressed in this paper. The presence of fractures in the subsurface, usually containing highly conductive pore fluids, gives rise to spatially hierarchical flow paths of induced EM eddy currents. The diffusion of EM eddy currents in such formations is anomalous, generalizing the classical Gaussian process described by the conventional Maxwell equations. Based on the continuous time random walk (CTRW) theory, the diffusion of EM eddy currents in a rough medium is governed by the fractional Maxwell equations. Here, we model the EM response of a 2D subsurface containing fractured zones, with a 3D loop source, which results the so-called 2.5D model geometry. The governing equation in the frequency domain is converted using Fourier transform into k domain along the strike direction (along which the model conductivity doesn't vary). The resulting equation system is solved by the multifrontal massively parallel solver (MUMPS). The data obtained is then converted back to spatial domain and the time domain. We find excellent agreement between the FD and analytic solutions for a rough halfspace model. Then FD solutions are calculated for a 2D fault zone model with variable conductivity and roughness. We compare the results with responses from several classical models and explore the relationship between the roughness and the spatial density of the fracture distribution.

Subsurface Exploration Technologies and Strategies for Europa

NASA Technical Reports Server (NTRS)

French, L. C.; Anderson, F. S.; Carsey, F. D.; Green, J. R.; Lane, A. L.; Zimmerman, W. F.

2001-01-01

The Galileo data from Europa has resulted in the strong suggestion of a large, cold, salty, old subglacial ocean and is of great importance. We have examined technology requirements for subsurface exploration of Europa and determined that scientific access to the hypothesized Europa ocean is a key requirement. By 'scientific access' we intend to direct attention to the fact that several aspects of exploration of a site such as Europa must be addressed at the system level. Specifically needed are a robotic vehicle that can descend through ice, scientific instrumentation that can interrogate the ice near the vehicle (but largely unaffected by its presence), scientific instrumentation for the subglacial ocean, communication for data and control, chemical analysis of the environment of the vehicle in the ice as well as the ocean, and methods for conducting the mission without contamination. We have embarked on a part of this extremely ambitious development sequence by developing the Active Thermal Probe, or Cryobot. Additional information is contained in the original extended abstract.

Subsurface Feature Mapping of Mars using a High Resolution Ground Penetrating Radar System

NASA Astrophysics Data System (ADS)

Wu, T. S.; Persaud, D. M.; Preudhomme, M. A.; Jurg, M.; Smith, M. K.; Buckley, H.; Tarnas, J.; Chalumeau, C.; Lombard-Poirot, N.; Mann, B.

2015-12-01

As the closest Earth-like, potentially life-sustaining planet in the solar system, Mars' future of human exploration is more a question of timing than possibility. The Martian surface remains hostile, but its subsurface geology holds promise for present or ancient astrobiology and future habitation, specifically lava tube (pyroduct) systems, whose presence has been confirmed by HiRISE imagery.The location and characterization of these systems could provide a basis for understanding the evolution of the red planet and long-term shelters for future manned missions on Mars. To detect and analyze the subsurface geology of terrestrial bodies from orbit, a novel compact (smallsat-scale) and cost-effective approach called the High-resolution Orbiter for Mapping gEology by Radar (HOMER) has been proposed. Adapting interferometry techniques with synthetic aperture radar (SAR) to a ground penetrating radar system, a small satellite constellation is able to achieve a theoretical resolution of 50m from low-Mars orbit (LMO). Alongside this initial prototype design of HOMER, proposed data processing methodology and software and a Mars mission design are presented. This project was developed as part of the 2015 NASA Ames Academy for Space Exploration.

Geo Techno Park potential at Arjuno-Welirang Volcano hosted geothermal area, Batu, East Java, Indonesia (Multi geophysical approach)

NASA Astrophysics Data System (ADS)

Maryanto, Sukir

2017-11-01

Arjuno Welirang Volcano Geothermal (AWVG) is located around Arjuno-Welirang Volcano in Malang, East Java, about 100 km southwest of Surabaya, the capital city of East Java province, and is still an undeveloped area of the geothermal field. The occurrence of solfatara and fumaroles with magmatic gasses indicated the existence of a volcanic geothermal system in the subsurface. A few hot springs are found in the Arjuno-Welirang volcanic complex, such as Padusan hot spring, Songgoriti hot spring, Kasinan hot spring, and Cangar hot spring. Multi geophysical observations in AWVG complex was carried out in order to explore the subsurface structure in supporting the plan of Geo Techno Park at the location. Gravity, Magnetic, Microearthquake, and Electrical Resistivity Tomography (ERT) methods were used to investigate the major and minor active faulting zones whether hot springs circulation occurs in these zones. The gravity methods allowed us to locate the subsurface structure and to evaluate their geometrical relationship base on density anomaly. Magnetic methods allow us to discriminate conductive areas which could correspond to an increase in thermal fluid circulation in the investigated sites. Micro-earthquakes using particle motion analysis to locate the focal depth related with hydrothermal activity and electrical resistivity tomography survey offers methods to locate more detail subsurface structure and geothermal fluids near the surface by identifying areas affected by the geothermal fluid. The magnetic and gravity anomaly indicates the subsurface structure of AWVG is composed of basalt rock, sulfide minerals, sandstone, and volcanic rock with high minor active fault structure as a medium for fluid circulation. While using micro-earthquake data in AWVG shown shallow focal depth range approximate 60 meters which indicates shallow hydrothermal circulation in AWVG. The geothermal fluid circulation zones along the fault structure resulted in some hot springs in a central and north-western part of AWVG detected by the Electrical Resistivity Tomography, appear to be well correlated with corresponding features derived from the gravity, magnetic, and micro-earthquake survey. We just ongoing process to develop Arjuno Welirang Volcano & Geothermal Research Center (AWVGRC) located at Universitas Brawijaya Agro Techno Park, Cangar in the flank of Arjuno Welirang volcano complex. Due to our initial observations, AWVG has a great potential for a pilot project of an educational geo technopark development area.

Hyporheic flow and transport processes: mechanisms, models, and biogeochemical implications

USGS Publications Warehouse

Boano, Fulvio; Harvey, Judson W.; Marion, Andrea; Packman, Aaron I.; Revelli, Roberto; Ridolfi, Luca; Anders, Wörman

2014-01-01

Fifty years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed."

Intraterrestrial life in igneous ocean crust: advances, technologies, and the future (Invited)

NASA Astrophysics Data System (ADS)

Edwards, K. J.; Wheat, C. G.

2010-12-01

The “next frontier” of scientific investigation in the deep sub-seafloor microbial biosphere lies in a realm that has been a completely unexplored until just the past decade: the igneous oceanic crust. Problems that have hampered exploration of the “hard rock” marine deep biosphere have revolved around sample access (hard rock drilling is technologically complex), contamination (a major hurdle), momentum (why take on this challenge when the relatively “easier” marine muds also have been a frontier) and suspicion that microbes in more readily accessed using (simpler) non-drilling technologies - like vents - are truly are endemic of subsurface clades/activities. Since the late 1990’s, however, technologies and resultant studies on microbes in the igneous ocean crust deep biosphere have risen sharply, and offer a new and distinct view on this biome. Moreover, microbiologists are now taking leading roles in technological developments that are critically required to address this biosphere - interfacing and collaborating closely with engineers, genomic biologists, geologists, seismologists, and geochemists to accomplish logistically complex and long-term studies that bring observatory research to this deep realm. The future of this field for the least decade is rich - opportunities abound for microbiologists to play new roles in how we study microbiology in the deep subsurface in an oceanographic and Earth system science perspective.

Thermodynamic and Kinetic Response of Microbial Reactions to High CO2.

PubMed

Jin, Qusheng; Kirk, Matthew F

2016-01-01

Geological carbon sequestration captures CO 2 from industrial sources and stores the CO 2 in subsurface reservoirs, a viable strategy for mitigating global climate change. In assessing the environmental impact of the strategy, a key question is how microbial reactions respond to the elevated CO 2 concentration. This study uses biogeochemical modeling to explore the influence of CO 2 on the thermodynamics and kinetics of common microbial reactions in subsurface environments, including syntrophic oxidation, iron reduction, sulfate reduction, and methanogenesis. The results show that increasing CO 2 levels decreases groundwater pH and modulates chemical speciation of weak acids in groundwater, which in turn affect microbial reactions in different ways and to different extents. Specifically, a thermodynamic analysis shows that increasing CO 2 partial pressure lowers the energy available from syntrophic oxidation and acetoclastic methanogenesis, but raises the available energy of microbial iron reduction, hydrogenotrophic sulfate reduction and methanogenesis. Kinetic modeling suggests that high CO 2 has the potential of inhibiting microbial sulfate reduction while promoting iron reduction. These results are consistent with the observations of previous laboratory and field studies, and highlight the complexity in microbiological responses to elevated CO 2 abundance, and the potential power of biogeochemical modeling in evaluating and quantifying these responses.

Thermodynamic and Kinetic Response of Microbial Reactions to High CO2

PubMed Central

Jin, Qusheng; Kirk, Matthew F.

2016-01-01

Geological carbon sequestration captures CO2 from industrial sources and stores the CO2 in subsurface reservoirs, a viable strategy for mitigating global climate change. In assessing the environmental impact of the strategy, a key question is how microbial reactions respond to the elevated CO2 concentration. This study uses biogeochemical modeling to explore the influence of CO2 on the thermodynamics and kinetics of common microbial reactions in subsurface environments, including syntrophic oxidation, iron reduction, sulfate reduction, and methanogenesis. The results show that increasing CO2 levels decreases groundwater pH and modulates chemical speciation of weak acids in groundwater, which in turn affect microbial reactions in different ways and to different extents. Specifically, a thermodynamic analysis shows that increasing CO2 partial pressure lowers the energy available from syntrophic oxidation and acetoclastic methanogenesis, but raises the available energy of microbial iron reduction, hydrogenotrophic sulfate reduction and methanogenesis. Kinetic modeling suggests that high CO2 has the potential of inhibiting microbial sulfate reduction while promoting iron reduction. These results are consistent with the observations of previous laboratory and field studies, and highlight the complexity in microbiological responses to elevated CO2 abundance, and the potential power of biogeochemical modeling in evaluating and quantifying these responses. PMID:27909425

Hyporheic flow and transport processes: Mechanisms, models, and biogeochemical implications

NASA Astrophysics Data System (ADS)

Boano, F.; Harvey, J. W.; Marion, A.; Packman, A. I.; Revelli, R.; Ridolfi, L.; Wörman, A.

2014-12-01

Fifty years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed.

Trends in maar crater size and shape using the global Maar Volcano Location and Shape (MaarVLS) database

NASA Astrophysics Data System (ADS)

Graettinger, A. H.

2018-05-01

A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a means of characterizing a global population of maar craters in order to establish the typical size and shape of features. A global database of Quaternary maar crater planform morphometry indicates that maar craters are typically not circular and frequently have compound shapes resembling overlapping circles. Maar craters occur in volcanic fields that contain both small volume and complex volcanoes. The global perspective provided by the database shows that maars are common in many volcanic and tectonic settings producing a similar diversity of size and shape within and between volcanic fields. A few exceptional populations of maars were revealed by the database, highlighting directions of future research to improve our understanding on the geometry and spacing of subsurface explosions that produce maars. These outlying populations, such as anomalously large craters (>3000 m), chains of maars, and volcanic fields composed of mostly maar craters each represent a small portion of the database, but provide opportunities to reinvestigate fundamental questions on maar formation. Maar crater morphometry can be integrated with structural, hydrological studies to investigate lateral migration of phreatomagmatic explosion location in the subsurface. A comprehensive database of intact maar morphometry is also beneficial for the hunt for maar-diatremes on other planets.

Two-dimensional resistivity investigation of the North Cavalcade Street site, Houston, Texas, August 2003

USGS Publications Warehouse

Kress, Wade H.; Teeple, Andrew

2005-01-01

Forward modeling was used as an interpretative tool to relate the subsurface distribution of resistivity from four DC resistivity lines to known, assumed, and hypothetical information on subsurface lithologies. The final forward models were used as an estimate of the true resistivity structure for the field data. The forward models and the inversion results of the forward models show the depth, thickness, and extent of strata as well as the resistive anomalies occurring along the four lines and the displacement of strata resulting from the Pecore Fault along two of the four DC resistivity lines. Ten additional DC resistivity lines show similarly distributed shallow subsurface lithologies of silty sand and clay strata. Eight priority areas of resistive anomalies were identified for evaluation in future studies. The interpreted DC resistivity data allowed subsurface stratigraphy to be extrapolated between existing boreholes resulting in an improved understanding of lithologies that can influence contaminant migration.

STRUCTURE AND FUNCTION OF SUBSURFACE MICROBIAL COMMUNITIES AFFECTING RADIONUCLIDE TRANSPORT AND BIOIMMOBILIZATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joel E. Kostka; Lee Kerkhof; Kuk-Jeong Chin

2011-06-15

The objectives of this project were to: (1) isolate and characterize novel anaerobic prokaryotes from subsurface environments exposed to high levels of mixed contaminants (U(VI), nitrate, sulfate), (2) elucidate the diversity and distribution of metabolically active metal- and nitrate-reducing prokaryotes in subsurface sediments, and (3) determine the biotic and abiotic mechanisms linking electron transport processes (nitrate, Fe(III), and sulfate reduction) to radionuclide reduction and immobilization. Mechanisms of electron transport and U(VI) transformation were examined under near in situ conditions in sediment microcosms and in field investigations at the Oak Ridge Field Research Center (ORFRC), in Oak Ridge, Tennessee, where themore » subsurface is exposed to mixed contamination predominated by uranium and nitrate. A total of 20 publications (16 published or 'in press' and 4 in review), 10 invited talks, and 43 contributed seminars/ meeting presentations were completed during the past four years of the project. PI Kostka served on one proposal review panel each year for the U.S. DOE Office of Science during the four year project period. The PI leveraged funds from the state of Florida to purchase new instrumentation that aided the project. Support was also leveraged by the PI from the Joint Genome Institute in the form of two successful proposals for genome sequencing. Draft genomes are now available for two novel species isolated during our studies and 5 more genomes are in the pipeline. We effectively addressed each of the three project objectives and research highlights are provided. Task I - Isolation and characterization of novel anaerobes: (1) A wide range of pure cultures of metal-reducing bacteria, sulfate-reducing bacteria, and denitrifying bacteria (32 strains) were isolated from subsurface sediments of the Oak Ridge Field Research Center (ORFRC), where the subsurface is exposed to mixed contamination of uranium and nitrate. These isolates which are new to science all show high sequence identity to sequences retrieved from ORFRC subsurface. (2) Based on physiological and phylogenetic characterization, two new species of subsurface bacteria were described: the metal-reducer Geobacter daltonii, and the denitrifier Rhodanobacter denitrificans. (3) Strains isolated from the ORFRC show that Rhodanobacter species are well adapted to the contaminated subsurface. Strains 2APBS1 and 116-2 grow at high salt (3% NaCl), low pH (3.5) and tolerate high concentrations of nitrate (400mM) and nitrite (100mM). Strain 2APBS1 was demonstrated to grow at in situ acidic pHs down to 2.5. (4) R. denitrificans strain 2APBS1 is the first described Rhodanobacter species shown to denitrify. Nitrate is almost entirely converted to N2O, which may account for the large accumulation of N2O in the ORFRC subsurface. (5) G. daltonii, isolated from uranium- and hydrocarbon-contaminated subsurface sediments of the ORFRC, is the first organism from the subsurface clade of the genus Geobacter that is capable of growth on aromatic hydrocarbons. (6) High quality draft genome sequences and a complete eco-physiological description are completed for R. denitrificans strain 2APBS1 and G. daltonii strain FRC-32. (7) Given their demonstrated relevance to DOE remediation efforts and the availability of detailed genotypic/phenotypic characterization, Rhodanobacter denitrificans strain 2APBS1 and Geobacter daltonii strain FRC-32 represent ideal model organisms to provide a predictive understanding of subsurface microbial activity through metabolic modeling. Tasks II and III-Diversity and distribution of active anaerobes and Mechanisms linking electron transport and the fate of radionuclides: (1) Our study showed that members of genus Rhodanobacter and Geobacter are abundant and active in the uranium and nitrate contaminated subsurface. In the contaminant source zone of the Oak Ridge site, Rhodanobacter spp. are the predominant, active organisms detected (comprising 50% to 100% of rRNA detected). (2) We demonstrated for the first time that the function of microbial communities can be quantified in subsurface sediments using messenger RNA assays (molecular proxies) under in situ conditions. (3) Active Geobacteraceae were identified and phylogenetically characterized from the cDNA of messenger RNA extracted from ORFRC subsurface sediment cores. Multiple clone sequences were retrieved from G. uraniireducens, G. daltonii, and G. metallireducens. (4) Results show that Geobacter strain FRC-32 is capable of growth on benzoate, toluene and benzene as the electron donor, thereby providing evidence that this strain is physiologically distinct from other described members of the subsurface Geobacter clade. (5) Fe(III)-reducing bacteria transform structural Fe in clay minerals from their layer edges rather than from their basal surfaces.« less

FIELD TRAPPING OF SUBSURFACE VAPOR PHASE PETROLEUM HYDROCARBONS

EPA Science Inventory

Soil gas samples from intact soil cores were collected on adsorbents at a field site, then thermally desorbed and analyzed by laboratory gas chromatography (GC). ertical concentration profiles of predominant vapor phase petroleum hydrocarbons under ambient conditions were obtaine...

FIELD-DRIVEN APPROACHES TO SUBSURFACE CONTAMINANT TRANSPORT MODELING.

EPA Science Inventory

Observations from field sites provide a means for prioritizing research activities. In the case of petroleum releases, observations may include spiking of concentration distributions that may be related to water table fluctuation, co-location of contaminant plumes with geochemi...

Location, Reprocessing, and Analysis of Two Dimensional Seismic Reflection Data on the Jicarilla Apache Indian Reservation, New Mexico, Final Report, September 1, 1997-February 1, 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ridgley, Jennie; Taylor, David J.; Huffman, Jr., A. Curtis

2000-06-08

Multichannel surface seismic reflection data recording is a standard industry tool used to examine various aspects of geology, especially the stratigraphic characteristics and structural style of sedimentary formations in the subsurface. With the help of the Jicarilla Apache Tribe and the Bureau of Indian Affairs we were able to locate over 800 kilometers (500 miles) of multichannel seismic reflection data located on the Jicarilla Apache Indian reservation. Most of the data was received in hardcopy form, but there were data sets where either the demultiplexed digital field data or the processed data accompanied the hardcopy sections. The seismic data wasmore » acquired from the mid 1960's to the early 1990's. The most extensive seismic coverage is in the southern part of the reservation, although there are two good surveys located on the northeastern and northwestern parts of the reservation. Most of the data show that subsurface formations are generally flat-lying in the southern and western portion of the reservation. There is, however, a significant amount of structure imaged on seismic data located over the San Juan Basin margin along the east-central and northern part of the reservation. Several west to east trending lines in these areas show a highly faulted monoclinal structure from the deep basin in the west up onto the basin margin to the east. Hydrocarbon exploration in flat lying formations is mostly stratigraphic in nature. Where there is structure in the subsurface and indications are that rocks have been folded, faulted, and fractured, exploration has concentrated on structural traps and porosity/permeability "sweet spots" caused by fracturing. Therefore, an understanding of the tectonics influencing the entire section is critical in understanding mechanisms for generating faults and fractures in the Cretaceous. It is apparent that much of the hydrocarbon production on the reservation is from fracture porosity in either source or reservoir sequences. Therefore it is important to understand the mechanism that controls the location and intensity of the fractures. A possible mechanism may be deep seated basement faulting that has been active through time. Examining the basement fault patterns in this part of the basin and their relation to fracture production may provide a model for new plays on the Jicarilla Indian Reservation. There are still parts of the reservation where the subsurface has not been imaged geophysically with either conventional two-dimensional or three-dimensional reflection seismic techniques. These methods, especially 3-D seismic, would provide the best data for mapping deep basement faulting. The authors would recommend that 3-D seismic be acquired along the Basin margin located along the eastern edge of the reservation and the results be used to construct detailed fault maps which may help to locate areas with the potential to contain highly fractured zones in the subsurface.« less

Reconnaissance geologic map of part of the San Isidro Quadrangle, Baja California Sur, Mexico

USGS Publications Warehouse

McLean, Hugh; Hausback, B.P.; Knapp, J.H.

1985-01-01

Mapping was done on aerial photographs and transferred, where possible, to 1:50,000-scale topographic base maps. Areas with roads were field checked; however, in the northeast part of the map area, lack of roads prevented field checks. Previous geologic surveys of parts of the map area were made by horseback in the early 1920's; reports were published by Darton (1921), Heim (1922), and Beal (1948). Subsurface data from petroleum exploration and a geologic map were incorporated in a regional study by Mina (1957). The first radiometric ages of rocks from the map area were published by Gastil and others (1979). Recently determined radiometric ages and chemical analysis of volcanic rocks were reported by Hausback (1984) and by Sawlan and Smith (1984). Our study incorporates geologic mapping with age control based on new radiometric ages as well as paleontology, Flows and tuffs were dated by the K-Ar method. Fossil ages are based on diatom and mollusk assemblages.

In-tank precipitation facility (ITP) and H-Tank Farm (HTF) geotechnical report, WSRC-TR-95-0057, Revision 0, Volume 5

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

A geotechnical study has been completed in H-Area for the In-Tank Precipitation Facility (ITP) and the balance of the H-Area Tank Farm (HTF) at the Savannah River Site (SRS) in South Carolina. The study consisted of subsurface field exploration, field and laboratory testing, and engineering analyses. The purpose of these investigations is to evaluate the overall stability of the H-Area tanks under static and dynamic conditions. The objectives of the study are to define the site-specific geological conditions at ITP and HTF, obtain engineering properties for the assessment of the stability of the native soils and embankment under static andmore » dynamic loads (i.e., slope stability, liquefaction potential, and potential settlements), and derive properties for soil-structure interaction studies. This document (Volume 5) contains the laboratory test results for the In-Tank Precipitation Facility (ITP) and H-Tank Farm (HTF) Geotechnical Report.« less

Integrating aeromagnetic and Landsat™ 8 data into subsurface structural mapping of Precambrian basement complex

NASA Astrophysics Data System (ADS)

Kayode, John Stephen; Nawawi, M. N. M.; Abdullah, Khiruddin B.; Khalil, Amin E.

2017-01-01

The integration of Aeromagnetic data and remotely sensed imagery with the intents of mapping the subsurface geological structures in part of the South-western basement complex of Nigeria was developed using the PCI Geomatica Software. 2013. The data obtained from the Nigerian Geological Survey Agency; was corrected using Regional Residual Separation of the Total Magnetic field anomalies enhanced, and International Geomagnetic Reference Field removed. The principal objective of this study is, therefore, to introduce a rapid and efficient method of subsurface structural depth estimate and structural index evaluation through the incorporation of the Euler Deconvolution technique into PCI Geomatica 2013 to prospect for subsurface geological structures. The shape and depth of burial helped to define these structures from the regional aeromagnetic map. The method enabled various structural indices to be automatically delineated for an index of between 0.5 SI and 3.0 SI at a maximum depth of 1.1 km that clearly showed the best depths estimate for all the structural indices. The results delineate two major magnetic belts in the area; the first belt shows an elongated ridge-like structure trending mostly along the NorthNortheast-SouthSouthwest and the other anomalies trends primarily in the Northeast, Northwest, Northeast-Southwest parts of the study area that could be attributed to basement complex granitic intrusions from the tectonic history of the area. The majority of the second structures showed various linear structures different from the first structure. Basically, a significant offset was delineated at the core segment of the study area, suggesting a major subsurface geological feature that controls mineralisation in this area.

The distribution of lingering subsurface oil from the Exxon Valdez oil spill

USGS Publications Warehouse

Michel, Jacqueline; Nixon, Zachary; Hayes, Miles O.; Irvine, Gail V.; Short, Jeffrey W.

2011-01-01

This study used field data and a suite of geospatial models to identify areas where subsurface oil is likely to still be present on the shorelines of Prince William Sound (PWS) and the Gulf of Alaska (GOA) affected by the Exxon Valdez oil spill, as well as the factors related to continued presence of such oil. The goal was to identify factors and accompanying models that could serve as screening tools to prioritize shorelines for different remediation methods. The models were based on data collected at 314 shoreline segments surveyed between 2001 and 2007. These field data allowed us to identify a number of geomorphologic and hydrologic factors that have contributed to the persistence of subsurface oil within PWS and GOA two decades after the spill. Because synoptic data layers for describing each of these factors at all locations were not available, the models developed used existing data sets as surrogates to represent these factors, such as distance to a stream mouth or shoreline convexity. While the linkages between the data used and the physical phenomena that drive persistence are not clearly understood in all cases, the performance of these models was remarkably good. The models simultaneously evaluate all identified variables to predict the presence of different types of subsurface oiling in a rigorous, unbiased manner. The refined model results suggest there are a limited but significant number of as-yet unsurveyed locations in the study area that are likely to contain subsurface oil. Furthermore, the model results may be used to quantitatively prioritize shoreline for investigation with known uncertainty.

Whole-stream metabolism of a perennial spring-fed aufeis field in Alaska, with coincident surface and subsurface flow

NASA Astrophysics Data System (ADS)

Hendrickson, P. J.; Gooseff, M. N.; Huryn, A. D.

2017-12-01

Aufeis (icings or naleds) are seasonal arctic and sub-arctic features that accumulate through repeated overflow and freeze events of river or spring discharge. Aufeis fields, defined as the substrate on which aufeis form and the overlaying ice, have been studied to mitigate impacts on engineering structures; however, ecological characteristics and functions of aufeis fields are poorly understood. The perennial springs that supply warm water to aufeis fields create unique fluvial habitats, and are thought to act as winter and summer oases for biota. To investigate ecosystem function, we measured whole-stream metabolism at the Kuparuk River Aufeis (North Slope, AK), a large ( 5 km2) field composed of cobble substrate and predominately subsurface flow dynamics. The single-station open channel diel oxygen method was utilized at several dissolved oxygen (DO) stations located within and downstream of the aufeis field. DO loggers were installed in August 2016, and data downloaded summer 2017. Daily ecosystem respiration (ER), gross primary production (GPP) and reaeration rates were modeled using BASE, a package freely available in the open-source software R. Preliminary results support net heterotrophy during a two-week period of DO measurements in the fall season when minimum ice extent is observed. GPP, ER, and net metabolism are greater at the upstream reach near the spring source (P/R = 0.53), and decrease as flow moves downstream. As flow exits the aufeis field, surface and subsurface flow are incorporated into the metabolism model, and indicate the stream system becomes dependent on autochthonous production (P/R = 0.91). Current work is directed towards spring and summer discharge and metabolic parameter estimation, which is associated with maximum ice extent and rapid melting of the aufeis feature.

Changing spatial patterns of evapotranspiration and deep drainage in response to the interactions among impervious surface arrangement, soil characteristics, and weather on a residential parcel.

NASA Astrophysics Data System (ADS)

Voter, C. B.; Steven, L. I.

2015-12-01

The introduction impervious surfaces in urban areas is a key driver of hydrologic change. It is now well understood that the amount of "effective" impervious area directly connected to the storm sewer network is a better indicator of hydrologic behavior than the total amount of impervious area. Most studies in urban hydrology have focused on the relationship between impervious connectivity and stormwater runoff or other surface water flows, with the result that the effect on subsurface flow is not as well understood. In the field, we observe differences in soil moisture availability that are dependent on proximity to impervious features and significant from a root water uptake perspective, which indicates that parcel-scale subsurface and plant water fluxes may also be sensitive to fine-scaled heterogeneity in impervious surface arrangement and connectivity. We use ParFlow with CLM, a watershed model with fully integrated variably-saturated subsurface flow, overland flow, and land-surface processes, to explore the extent to which soil moisture, evapotranspiration, and deep drainage vary under various impervious surface arrangement and soil condition scenarios, as well as under a range of precipitation regimes. We investigate the effect of several impervious surface and soil characteristics, including general lot layout, downspout disconnect, and direction of driveway/sidewalk slope, and soil compaction. We show that that some impervious connectivity schemes transfer more water from impervious areas to pervious ones and promote localized recharge by developing well-defined, fast-moving wetting fronts that are able to penetrate the root zone. Enhanced infiltration is translated more directly to recharge in normal to wet years but partitioned more often to transpiration in dry years, leading to a nonlinear relationship among precipitation, runoff and recharge.

Enceladus Environmental Explorer (EVE): A Mission Concept

NASA Astrophysics Data System (ADS)

Lawson, M. J.; Amador, E. S.; Carrier, B. L.; Albuja, A.; Bapst, J.; Cahill, K. R. S.; Ebersohn, F.; Gainey, S.; Gartrelle, G.; Greenberger, R. N.; Hale, J. M.; Johnston, S.; Olivares, J.; Parcheta, C. E.; Sheehan, J. P.; Thorpe, A. K.; Zareh, S. K.

2014-12-01

Enceladus is an intriguing planetary body, which possibly has the ingredients needed for life. Further, it has numerous (over 100) continuously erupting geysers that eject material into the atmosphere which provide a unique opportunity to sample the body's internal chemistry from orbit. At JPL's Planetary Science Summer School, Team X and a group of students developed a mission concept to directly sample Enceladus' plumes. The mission, named Enceladus Environmental Explorer (EVE), follows NASA's Planetary Science Decadal survey and would assess the potential habitability of Saturn's icy satellite through analysis of the chemistry of the subsurface ocean and the nature of the organic chemistry in the plume. EVE would look at geological and geophysical surface processes of Enceladus by investigating the heat output of Enceladus, plumes' mechanics, the extent of the liquid subsurface reservoir(s), and gravitational variation. The EVE mission concept aimed for a January 2023 launch on an Atlas 551 class launch vehicle and would arrive at Saturn July 2031. A two-year-long Saturn moon tour would allow sufficient deceleration to permit a polar orbital insertion around Enceladus in March 2035, remaining stable for 54 weeks of observation. The proposed instrument payload includes: 1) SUb MilliMeter Enceladus Radiometer (SUMMER; equivalent to Rosetta MIRO), 2) Enceladus Dust and Gas Experiment (EDGE; an enhanced version of Rosetta COSIMA), 3) MAGnetometer for Ionic Concentration (MAGIC; equivalent to MMS/ InSIGHT magnetometer), 4) Visual Imaging Camera with Topographic Observational Resolution (VICTOR) and 5) Enceladus Radio Gravity Science (ERGS). Our suggested orbital timeline would allow the most comprehensive dataset yet collected of a moon in the outer solar system, mapping the entire surface twice with SUMMER and VICTOR, while sampling the plume directly 232 times with EDGE. MAGIC would also provide over a year of sampling of the magnetic field variations from orbit. Enceladus Environmental Explorer (EVE) offers a unique opportunity to determine the potential for life on Enceladus.

Influence of subsurface defects on damage performance of fused silica in ultraviolet laser

NASA Astrophysics Data System (ADS)

Huang, Jin; Zhou, Xinda; Liu, Hongjie; Wang, Fengrui; Jiang, Xiaodong; Wu, Weidong; Tang, Yongjian; Zheng, Wanguo

2013-02-01

In ultraviolet pulse laser, damage performance of fused silica optics is directly dependent on the absorptive impurities and scratches in subsurface, which are induced by mechanical polishing. In the research about influence of subsurface defects on damage performance, a series of fused silica surfaces with various impurity concentrations and scratch structures were created by hydrofluoric (HF) acid solution etching. Time of Flight secondary ion mass spectrometry and scanning probe microprobe revealed that with increasing etching depth, impurity concentrations in subsurface layers are decreased, the scratch structures become smoother and the diameter:depth ratio is increased. Damage performance test with 355-nm pulse laser showed that when 600 nm subsurface thickness is removed by HF acid etching, laser-induced damage threshold of fused silica is raised by 40 percent and damage density is decreased by over one order of magnitude. Laser weak absorption was tested to explain the cause of impurity elements impacting damage performance, field enhancement caused by change of scratch structures was calculated by finite difference time domain simulation, and the calculated results are in accord with the damage test results.

Paleokarst processes in the Eocene limestones of the Pyramids Plateau, Giza, Egypt

NASA Astrophysics Data System (ADS)

El Aref, M. M.; Refai, E.

The Eocene limestones of the Pyramids plateau are characterized by landforms of stepped terraced escarpment and karst ridges with isolated hills. The carbonate country rocks are also dominated by minor surface, surface to subsurface and subsurface solution features associated with karst products. The systematic field observations eludicate the denudation trend of the minor solution features and suggest the origin of the regional landscapes. The lithologic and structural characters of the limestone country rocks comprise the main factors controlling the surface and subsurface karst evolution. The development of the karst features and the associated sediments in the study area provides information on the paleohydrolic, chemical and climatic environments involved in the origin of the karstification.

Clays and Carbonates in a Groundwater-Fed 3.8 Ga Martian Lake: Insights to Subsurface Habitability on Mars

NASA Technical Reports Server (NTRS)

Michalski, Joseph; Niles, Paul

2015-01-01

On Earth, the deep biosphere remains a largely unexplored, but clearly important carbon reservoir. Results from some uplifted central peaks in craters on Mars indicate that substantial carbon was also present at depth and might have helped sustain a deep biosphere. In fact, many factors relevant to deep biosphere habitability are more favorable on Mars than on Earth (e.g. porosity of the crust, geothermal gradient). Future exploration of Mars should include landing sites where materials have been exhumed from depth by meteor impact or basins where subsurface fluids have emerged, carrying clues to subsurface habitability. One of the most astrobiologically interesting sites on Mars McLaughlin Crater, a 93 km-diameter impact crater that formed approximately 4 b.y. ago. On the floor of the crater is a stratigraphic section of subhorizontal, layered sedimentary rocks with strong spectroscopic evidence for Fe-rich clay minerals and Mg-rich carbonates, which we interpret as ancient lacustrine deposits. The fluids that formed these materials likely originated in the subsurface, based on the paucity of channels leading into the crater basin and the fact that this is one of the deepest basins on Mars - a good candidate to have experienced upwelling of subsurface fluids. Therefore, the deposits within McLaughlin crater provide insight into subsurface processes on Mars. In this presentation, we will discuss the habitability of the martian subsurface as well as the geology of McLaughlin Crater and the possibility to detect biomarkers at that site with a future landed mission.

Moon Diver: A Discovery Mission Concept for Understanding the History of the Mare Basalts Through the Exploration of a Lunar Mare Pit

NASA Astrophysics Data System (ADS)

Kerber, L.; Nesnas, I.; Keszthelyi, L.; Head, J. W.; Denevi, B.; Hayne, P. O.; Mitchell, K.; Ashley, J. W.; Whitten, J. L.; Stickle, A. M.; Parness, A.; McGarey, P.; Paton, M.; Donaldson-Hanna, K.; Anderson, R. C.; Needham, D.; Isaacson, P.; Jozwiak, L.; Bleacher, J.; Parcheta, C.

2018-04-01

Moon Diver is a Discovery-class mission concept designed to explore a lunar mare pit. It would be the first mission to examine an in-place bedrock stratigraphy on the Moon, and the first to venture into the subsurface of another planetary body.

Estimation of subsurface formation temperature in the Tarim Basin, northwest China: implications for hydrocarbon generation and preservation

NASA Astrophysics Data System (ADS)

Liu, Shaowen; Lei, Xiao; Feng, Changge; Hao, Chunyan

2016-07-01

Subsurface formation temperature in the Tarim Basin, northwest China, is vital for assessment of hydrocarbon generation and preservation, and of geothermal energy potential. However, it has not previously been well understood, due to poor data coverage and a lack of highly accurate temperature data. Here, we combined recently acquired steady-state temperature logging data with drill stem test temperature data and measured rock thermal properties, to investigate the geothermal regime and estimate the subsurface formation temperature at depth in the range of 1000-5000 m, together with temperatures at the lower boundary of each of four major Lower Paleozoic marine source rocks buried in this basin. Results show that heat flow of the Tarim Basin ranges between 26.2 and 66.1 mW/m2, with a mean of 42.5 ± 7.6 mW/m2; the geothermal gradient at depth of 3000 m varies from 14.9 to 30.2 °C/km, with a mean of 20.7 ± 2.9 °C/km. Formation temperature estimated at the depth of 1000 m is between 29 and 41 °C, with a mean of 35 °C, while 63-100 °C is for the temperature at the depth of 3000 m with a mean of 82 °C. Temperature at 5000 m ranges from 97 to 160 °C, with a mean of 129 °C. Generally spatial patterns of the subsurface formation temperature at depth are basically similar, characterized by higher temperatures in the uplift areas and lower temperatures in the sags, which indicates the influence of basement structure and lateral variations in thermal properties on the geotemperature field. Using temperature to identify the oil window in the source rocks, most of the uplifted areas in the basin are under favorable condition for oil generation and/or preservation, whereas the sags with thick sediments are favorable for gas generation and/or preservation. We conclude that relatively low present-day geothermal regime and large burial depth of the source rocks in the Tarim Basin are favorable for hydrocarbon generation and preservation. In addition, it is found that the oil and gas fields discovered in the Tarim Basin are usually associated with relatively high-temperature anomalies, and the upward migration and accumulation of hot geofluids along faults as conduit from below could explain this coincidence. Accordingly, this thermal anomaly could be indicative of hydrocarbon exploration targets in the basin.

Surface electrical properties experiment study phase, volume 2

NASA Technical Reports Server (NTRS)

1973-01-01

The choice of an antenna for a subsurface radio sounding experiment is discussed. The radiation properties of the antennas as placed on the surface of the medium is examined. The objective of the lunar surface electrical properties experiment is described. A numerical analysis of the dielectric permittivity and magnetic permeability of a subsurface domain is developed. The application of electromagnetic field measurements between one or more transmitting antennas and a roving receiving station is explained.

Quantifying hyporheic exchange dynamics in a highly regulated large river reach.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, Glenn Edward; Zhou, T; Huang, M

Hyporheic exchange is an important mechanism taking place in riverbanks and riverbed sediments, where river water and shallow groundwater mix and interact with each other. The direction, magnitude, and residence time of the hyporheic flux that penetrates the river bed are critical for biogeochemical processes such as carbon and nitrogen cycling, and biodegradation of organic contaminants. Many approaches including field measurements and numerical methods have been developed to quantify the hyporheic exchanges in relatively small rivers. However, the spatial and temporal distributions of hyporheic exchanges in a large, regulated river reach remain less explored due to the large spatial domains,more » complexity of geomorphologic features and subsurface properties, and the great pressure gradient variations at the riverbed created by dam operations.« less

Lander Trench Dug by Opportunity

NASA Image and Video Library

2015-01-27

On March 20, 2004, NASA Mars Exploration Rover Opportunity used a wheel to dig a trench revealing subsurface material beside the lander hardware that carried the rover to the surface of Mars 55 Martian days earlier.

Forward modeling of gravity data using geostatistically generated subsurface density variations

USGS Publications Warehouse

Phelps, Geoffrey

2016-01-01

Using geostatistical models of density variations in the subsurface, constrained by geologic data, forward models of gravity anomalies can be generated by discretizing the subsurface and calculating the cumulative effect of each cell (pixel). The results of such stochastically generated forward gravity anomalies can be compared with the observed gravity anomalies to find density models that match the observed data. These models have an advantage over forward gravity anomalies generated using polygonal bodies of homogeneous density because generating numerous realizations explores a larger region of the solution space. The stochastic modeling can be thought of as dividing the forward model into two components: that due to the shape of each geologic unit and that due to the heterogeneous distribution of density within each geologic unit. The modeling demonstrates that the internally heterogeneous distribution of density within each geologic unit can contribute significantly to the resulting calculated forward gravity anomaly. Furthermore, the stochastic models match observed statistical properties of geologic units, the solution space is more broadly explored by producing a suite of successful models, and the likelihood of a particular conceptual geologic model can be compared. The Vaca Fault near Travis Air Force Base, California, can be successfully modeled as a normal or strike-slip fault, with the normal fault model being slightly more probable. It can also be modeled as a reverse fault, although this structural geologic configuration is highly unlikely given the realizations we explored.

Strategies towards an optimized use of the shallow geothermal potential

NASA Astrophysics Data System (ADS)

Schelenz, S.; Firmbach, L.; Kalbacher, T.; Goerke, U.; Kolditz, O.; Dietrich, P.; Vienken, T.

2013-12-01

Thermal use of the shallow subsurface for heat generation, cooling and thermal energy storage is increasingly gaining importance in reconsideration of future energy supplies, e.g. in the course of German energy transition, with application shifting from isolated to intensive use. The planning and dimensioning of (geo-)thermal applications is strongly influenced by the availability of exploration data. Hence, reliable site-specific dimensioning of systems for the thermal use of the shallow subsurface will contribute to an increase in resource efficiency, cost reduction during installation and operation, as well as reduction of environmental impacts and prevention of resource over-exploitation. Despite large cumulative investments that are being made for the utilization of the shallow thermal potential, thermal energy is in many cases exploited without prior on-site exploration and investigation of the local geothermal potential, due to the lack of adequate and cost-efficient exploration techniques. We will present new strategies for an optimized utilization of urban thermal potential, showcased at a currently developed residential neighborhood with high demand for shallow geothermal applications, based on a) enhanced site characterization and b) simulation of different site specific application scenarios. For enhanced site characterization, surface geophysics and vertical high resolution direct push-profiling were combined for reliable determination of aquifer structure and aquifer parameterization. Based on the site characterization, different site specific geothermal application scenarios, including different system types and system configurations, were simulated using OpenGeoSys to guarantee an environmental and economic sustainable thermal use of the shallow subsurface.

The Simulation of Temperature Field Based on 3D Modeling and Its Comparison versus Measured Temperature Distribution of Daqing Oilfield, NE China

NASA Astrophysics Data System (ADS)

Shi, Y.; Jiang, G.; Hu, S.

2017-12-01

Daqing, as the largest oil field of China with more than 50 years of exploration and production history for oil and gas, its geothermal energy utilization was started in 2000, with a main focus on district heating and direct use. In our ongoing study, data from multiple sources are collected, including BHT, DST, steady state temperature measurements in deep wells and thermophysical properties of formations. Based on these measurements, an elaborate investigation of the temperature field of Daqing Oilfield is made. Moreover, through exploration for oil and gas, subsurface geometry, depth, thickness and properties of the stratigraphic layers have been extensively delineated by well logs and seismic profiles. A 3D model of the study area is developed incorporating the information of structure, stratigraphy, basal heat flow, and petrophysical and thermophysical properties of strata. Based on the model, a simulation of the temperature field of Daqing Oilfield is generated. A purely conductive regime is presumed, as demonstrated by measured temperature log in deep wells. Wells W1, W2 and SK2 are used as key wells for model calibration. Among them, SK2, as part of the International Continental Deep Drilling Program, has a designed depth of 6400m, the steady state temperature measurement in the borehole has reached the depth of 4000m. The results of temperature distribution generated from simulation and investigation are compared, in order to evaluate the potential of applying the method to other sedimentary basins with limited borehole temperature measurements but available structural, stratigraphic and thermal regime information.

Spatiotemporal monitoring of soil water content profiles in an irrigated field using probabilistic inversion of time-lapse EMI data

NASA Astrophysics Data System (ADS)

Moghadas, Davood; Jadoon, Khan Zaib; McCabe, Matthew F.

2017-12-01

Monitoring spatiotemporal variations of soil water content (θ) is important across a range of research fields, including agricultural engineering, hydrology, meteorology and climatology. Low frequency electromagnetic induction (EMI) systems have proven to be useful tools in mapping soil apparent electrical conductivity (σa) and soil moisture. However, obtaining depth profile water content is an area that has not been fully explored using EMI. To examine this, we performed time-lapse EMI measurements using a CMD mini-Explorer sensor along a 10 m transect of a maize field over a 6 day period. Reference data were measured at the end of the profile via an excavated pit using 5TE capacitance sensors. In order to derive a time-lapse, depth-specific subsurface image of electrical conductivity (σ), we applied a probabilistic sampling approach, DREAM(ZS) , on the measured EMI data. The inversely estimated σ values were subsequently converted to θ using the Rhoades et al. (1976) petrophysical relationship. The uncertainties in measured σa, as well as inaccuracies in the inverted data, introduced some discrepancies between estimated σ and reference values in time and space. Moreover, the disparity between the measurement footprints of the 5TE and CMD Mini-Explorer sensors also led to differences. The obtained θ permitted an accurate monitoring of the spatiotemporal distribution and variation of soil water content due to root water uptake and evaporation. The proposed EMI measurement and modeling technique also allowed for detecting temporal root zone soil moisture variations. The time-lapse θ monitoring approach developed using DREAM(ZS) thus appears to be a useful technique to understand spatiotemporal patterns of soil water content and provide insights into linked soil moisture vegetation processes and the dynamics of soil moisture/infiltration processes.

Foldbelt exploration with synthetic aperture radar (SAR) in Papua New Guinea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, J.M.; Pruett, F.D.

1987-05-01

Synthetic aperture radar (SAR) is being successfully used within the southern fold and thrust belt of Papua New Guinea to map surface structure and stratigraphy and to help plan a hydrocarbon exploration program. The airborne SAR imagery, along with other surface data, is used as a primary exploration tool because acquisition of acceptable seismic data is extremely costly due to extensive outcrops of Tertiary Darai Limestone which develops rugged karst topography. Most anticlines in the licenses are capped with this deeply karstified limestone. The region is ideally suited to geologic analysis using remote sensing technology. The area is seldom cloudmore » free and is covered with tropical rain forest, and geologic field studies are limited. The widespread karst terrain is exceedingly dangerous, if not impossible, to traverse on the ground. SAR is used to guide ongoing field work, modeling of subsurface structure, and selection of well locations. SAR provides their explorationists with an excellent data base because (1) structure is enhanced with low illumination, (2) resolution is 6 x 12 m, (3) digital reprocessing is possible, (4) clouds are penetrated by the SAR, and (5) the survey was designed for stereoscopic photogeology. Landsat images and vertical aerial photographs complement SAR but provide subdued structural information because of minimal shadowing (due to high sun angles) and the jungle cover. SAR imagery reveals large-scale mass wasting that has led to a reevaluation of previously acquired field data. Lithologies can be recognized by textural and tonal changes on the SAR images despite near-continuous canopy of jungle. Reprocessing and contrast stretching of the digital radar imagery provide additional geologic information.« less

REMOVAL OF ISOPROPHYL ALCOHOL FROM A SURFACTANT-BASED SOIL REMEDIATION FLUID BY PERVAPORATION: PILOT SCALE FIELD DEMONSTRATION

EPA Science Inventory

The USEPA, NRMRL participated in a field demonstration of a surfactant enhanced aquifer remediation (SEAR) process. The main purpose of this field demonstration was to combine and optimize the subsurface extraction of a dense non-aqueous phase liquid with the above ground deconta...

Rye cover crop and gamagrass strip effects on NO3 concentration and load in tile drainage.

PubMed

Kaspar, T C; Jaynes, D B; Parkin, T B; Moorman, T B

2007-01-01

A significant portion of the NO3 from agricultural fields that contaminates surface waters in the Midwest Corn Belt is transported to streams or rivers by subsurface drainage systems or "tiles." Previous research has shown that N fertilizer management alone is not sufficient for reducing NO3 concentrations in subsurface drainage to acceptable levels; therefore, additional approaches need to be devised. We compared two cropping system modifications for NO3 concentration and load in subsurface drainage water for a no-till corn (Zea mays L.)-soybean (Glycine max [L.] Merr.) management system. In one treatment, eastern gamagrass (Tripsacum dactyloides L.) was grown in permanent 3.05-m-wide strips above the tiles. For the second treatment, a rye (Secale cereale L.) winter cover crop was seeded over the entire plot area each year near harvest and chemically killed before planting the following spring. Twelve 30.5x42.7-m subsurface-drained field plots were established in 1999 with an automated system for measuring tile flow and collecting flow-weighted samples. Both treatments and a control were initiated in 2000 and replicated four times. Full establishment of both treatments did not occur until fall 2001 because of dry conditions. Treatment comparisons were conducted from 2002 through 2005. The rye cover crop treatment significantly reduced subsurface drainage water flow-weighted NO3 concentrations and NO3 loads in all 4 yr. The rye cover crop treatment did not significantly reduce cumulative annual drainage. Averaged over 4 yr, the rye cover crop reduced flow-weighted NO3 concentrations by 59% and loads by 61%. The gamagrass strips did not significantly reduce cumulative drainage, the average annual flow-weighted NO3 concentrations, or cumulative NO3 loads averaged over the 4 yr. Rye winter cover crops grown after corn and soybean have the potential to reduce the NO3 concentrations and loads delivered to surface waters by subsurface drainage systems.

A passive low frequency instrument for radio wave sounding the subsurface oceans of the Jovian icy moons: An instrument concept

NASA Astrophysics Data System (ADS)

Hartogh, P.; Ilyushin, Ya. A.

2016-10-01

Exploration of subsurface oceans on Jovian icy moons is a key issue of the icy moons' geology. Electromagnetic wave propagation is the only way to probe their icy mantles from the orbit. In the present paper, a principal concept of a passive interferometric instrument for deep sounding of the icy moons' crust is proposed. Its working principle is measuring and correlating Jupiter's radio wave emissions with reflections from the deep sub-surface of the icy moons. A number of the functional aspects of the proposed experiment are studied, in particular, impact of the wave scattering on the surface terrain on the instrument performance and digital sampling of the noisy signal. Results of the test of the laboratory prototype of the instrument are also presented in the paper.

Microbial-sized, carboxylate-modified microspheres as surrogate tracers in a variety of subsurface environments: An overview

USGS Publications Warehouse

Harvey, Ronald W.; Metge, David W.; LeBlanc, Denis R.

2017-01-01

Since 1986, fluorescent carboxylate-modified polystyrene/latex microspheres (FCM) have been co-injected into aquifers along with conservative tracers and viruses, bacteria, and (or) protozoa. Use of FCM has resulted in new information about subsurface transport behaviors of microorganisms in fractured crystalline rock, karst limestone, soils, and granular aquifers. FCM have been used as surrogates for oocysts of the pathogenic protist Cryptosporidium parvum in karst limestone and granular drinking-water aquifers. The advantages of FCM in subsurface transport studies are that they are safe in tracer applications, negatively charged, easy to detect, chemically inert, and available in wide range of sizes. The limitations of FCM are that the quantities needed for some field transport studies can be prohibitively expensive and that their surface characteristics may not match the microorganisms of interest. These limitations may be ameliorated, in part by using chemically modified FCM so that their surface characteristics are a better match to that of the organisms. Also, more sensitive methods of detection may allow using smaller quantities of FCM. To assess how the transport behaviors of FCM and pathogens might compare at the field scale, it is helpful to conduct side-by-side comparisons of their transport behaviors using the geologic media and site-specific conditions that characterize the field site.

3-D seismology in the Arabian Gulf

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Husseini, M.; Chimblo, R.

Since 1977 when Aramco and GSI (Geophysical Services International) pioneered the first 3-D seismic survey in the Arabian Gulf, under the guidance of Aramco`s Chief Geophysicist John Hoke, 3-D seismology has been effectively used to map many complex subsurface geological phenomena. By the mid-1990s extensive 3-D surveys were acquired in Abu Dhabi, Oman, Qatar and Saudi Arabia. Also in the mid-1990`s Bahrain, Kuwait and Dubai were preparing to record surveys over their fields. On the structural side 3-D has refined seismic maps, focused faults and fractures systems, as well as outlined the distribution of facies, porosity and fluid saturation. Inmore » field development, 3D has not only reduced drilling costs significantly, but has also improved the understanding of fluid behavior in the reservoir. In Oman, Petroleum Development Oman (PDO) has now acquired the first Gulf 4-D seismic survey (time-lapse 3D survey) over the Yibal Field. The 4-D survey will allow PDO to directly monitor water encroachment in the highly-faulted Cretaceous Shu`aiba reservoir. In exploration, 3-D seismology has resolved complex prospects with structural and stratigraphic complications and reduced the risk in the selection of drilling locations. The many case studies from Saudi Arabia, Oman, Qatar and the United Arab Emirates, which are reviewed in this paper, attest to the effectiveness of 3D seismology in exploration and producing, in clastics and carbonates reservoirs, and in the Mesozoic and Paleozoic.« less

Similarities and Differences in the Distributions of Hydrothermal Venting and the Formation of Seafloor Massive Sulfide Deposits at the Tui Malila and Mariner Vent Fields, Valu Fa Ridge

NASA Astrophysics Data System (ADS)

Tivey, M. K.; Evans, G. N.; Ferrini, V. L.; Spierer, H.

2016-12-01

High-resolution bathymetric mapping and recovery and study of samples from precisely known locations relative to local tectonic and volcanic features provide insight into the formation of seafloor massive sulfide deposits. Additional insight comes from repeat mapping efforts in 2005 and 2016 that provide details of relations and changes that may have occurred over time. Located 21 km apart on the Valu Fa Ridge, the Tui Malila and Mariner vent fields exhibit contrasting vent fluid chemistry, mineral deposit composition, deposit morphology, and seafloor morphology. At the Tui Malila vent field, near-neutral pH fluids with low metal contents vent from Zn- and Ba-rich, but Cu-poor deposits. The highest temperature fluids are found near the intersection of two faults and between volcanic domes. In contrast, acidic, metal-rich hydrothermal fluids at the Mariner vent field vent from Cu-rich, Zn-poor deposits. No discernable faults are present. At both the Tui Malila and Mariner vent fields, intermediate temperature fluids were sampled emanating from barite-rich deposits. At the Tui Malila vent field, intermediate fluids vent from flange-dominated edifices that are located on brecciated lava flow that overlays one of the two faults. Intermediate fluids at the Mariner vent field vent from squat terrace-like edifices located peripheral (10-15 m) to high-temperature chimney edifices, and seafloor morphology is dominated by brecciated lava flows. Thermodynamic models of mixing between high-temperature hydrothermal fluids and seawater that consider subsurface deposition of sulfide minerals and iron oxyhydroxide were used to reproduce the chemistry of intermediate fluids. This study suggests that the porous, brecciated lavas characteristic of these two vent fields provide sites for subsurface mixing and contribute to mineral deposition, with the faults at the Tui Malila vent field providing a pathway for subsurface fluid flow.

Space Station Views of African Sedimentary Basins-Analogs for Subsurface Patterns

NASA Technical Reports Server (NTRS)

Wilkinson, M. Justin

2007-01-01

Views of African sedimentary basins from the International Space Station (ISS) is presented. The images from ISS include: 1) Inland deltas; 2) Prediction; 3) Significance; 4) Exploration applications; and 5) Coastal megafans

Role of subsurface ocean in decadal climate predictability over the South Atlantic.

PubMed

Morioka, Yushi; Doi, Takeshi; Storto, Andrea; Masina, Simona; Behera, Swadhin K

2018-06-04

Decadal climate predictability in the South Atlantic is explored by performing reforecast experiments using a coupled general circulation model with two initialization schemes; one is assimilated with observed sea surface temperature (SST) only, and the other is additionally assimilated with observed subsurface ocean temperature and salinity. The South Atlantic is known to undergo decadal variability exhibiting a meridional dipole of SST anomalies through variations in the subtropical high and ocean heat transport. Decadal reforecast experiments in which only the model SST is initialized with the observation do not predict well the observed decadal SST variability in the South Atlantic, while the other experiments in which the model SST and subsurface ocean are initialized with the observation skillfully predict the observed decadal SST variability, particularly in the Southeast Atlantic. In-depth analysis of upper-ocean heat content reveals that a significant improvement of zonal heat transport in the Southeast Atlantic leads to skillful prediction of decadal SST variability there. These results demonstrate potential roles of subsurface ocean assimilation in the skillful prediction of decadal climate variability over the South Atlantic.

Research on subsurface deformed layer in ultra-precision cutting of single crystal copper by focused ion beam etching method

NASA Astrophysics Data System (ADS)

Chen, Y.; Huang, X. J.; Kong, J. X.

2018-03-01

In this paper, the focused ion beam was used to study the subsurface deformed layer of single crystal copper caused by the nanoscale single-point diamond fly cutting, and the possibility of using nanometer ultra-precision cutting to remove the larger deformation layer caused by traditional rough cutting process was explored. The maximum cutting thickness of single-point diamond cutting was about 146 nm, and the surface of the single-crystal copper after cutting was etched and observed by using the focused ion beam method. It was found that the morphology of the near-surface layer and the intermediate layer of the copper material were larger differences: the near-surface of the material was smaller and more compact, and the intermediate material layer of the material was more coarse sparse. The results showed that the traditional precision cutting would residual significant subsurface deformed layer and the thickness was on micron level. Even more, the subsurface deformed layer was obviously removed from about 12μm to 5μm after single-point diamond fly cutting in this paper. This paper proved that the large-scale subsurface deformed layer caused by traditional cutting process could be removed by nanometer ultra-precision cutting. It was of great significance to further establish the method that control of the deformation of weak rigid components by reducing the depth of the subsurface deformed layers.

Watershed scale fungal community characterization along a pH gradient in a subsurface environment co-contaminated with uranium and nitrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jasrotia, Puja; Green, Stefan; Canion, Andy

2014-01-01

The objective of this study was to characterize fungal communities in a subsurface environment co-contaminated with uranium and nitrate at the watershed scale, and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution and diversity of fungi in subsurface groundwater samples were determined using quantitative and semi-quantitative molecular techniques, including quantitative PCR of eukaryotic SSU rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from subsurface. Our results demonstrate that subsurface fungalmore » communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH < 4.5) conditions. Fungal isolates recovered from subsurface sediments were shown to reduce nitrate to nitrous oxide, including cultures of the genus Coniochaeta that were detected in abundance in pyrosequence libraries of site groundwater samples. Denitrifying fungal isolates recovered from the site were classified, and found to be distributed broadly within the phylum Ascomycota, and within a single genus within the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions.« less

Influence of bedrock topography on the runoff generation under use of ERT data

NASA Astrophysics Data System (ADS)

Kiese, Nina; Loritz, Ralf; Allroggen, Niklas; Zehe, Erwin

2017-04-01

Subsurface topography has been identified to play a major role for the runoff generation in different hydrological landscapes. Sinks and ridges in the bedrock can control how water is stored and transported to the stream. Detecting the subsurface structure is difficult and laborious and frequently done by auger measurements. Recently, the geophysical imaging of the subsurface by Electrical Resistivity Tomography (ERT) gained much interest in the field of hydrology, as it is a non-invasive method to collect information on the subsurface characteristics and particularly bedrock topography. As it is impossible to characterize the subsurface of an entire hydrological landscape using ERT, it is of key interest to identify the bedrock characteristics which dominate runoff generation to adapt and optimize the sampling design to the question of interest. For this study, we used 2D ERT images and auger measurements, collected on different sites in the Attert basin in Luxembourg, to characterize bedrock topography using geostatistics and shed light on those aspects which dominate runoff generation. Based on ERT images, we generated stochastic bedrock topographies and implemented them in a physically-based 2D hillslope model. With this approach, we were able to test the influence of different subsurface structures on the runoff generation. Our results highlight that ERT images can be useful for hydrological modelling. Especially the connection from the hillslope to the stream could be identified as important feature in the subsurface for the runoff generation whereas the microtopography of the bedrock seemed to be less relevant.

Watershed-Scale Fungal Community Characterization along a pH Gradient in a Subsurface Environment Cocontaminated with Uranium and Nitrate

PubMed Central

Jasrotia, Puja; Green, Stefan J.; Canion, Andy; Overholt, Will A.; Prakash, Om; Wafula, Denis; Hubbard, Daniela; Watson, David B.; Schadt, Christopher W.; Brooks, Scott C.

2014-01-01

The objective of this study was to characterize fungal communities in a subsurface environment cocontaminated with uranium and nitrate at the watershed scale and to determine the potential contribution of fungi to contaminant transformation (nitrate attenuation). The abundance, distribution, and diversity of fungi in subsurface groundwater samples were determined using quantitative and semiquantitative molecular techniques, including quantitative PCR of eukaryotic small-subunit rRNA genes and pyrosequencing of fungal internal transcribed spacer (ITS) regions. Potential bacterial and fungal denitrification was assessed in sediment-groundwater slurries amended with antimicrobial compounds and in fungal pure cultures isolated from the subsurface. Our results demonstrate that subsurface fungal communities are dominated by members of the phylum Ascomycota, and a pronounced shift in fungal community composition occurs across the groundwater pH gradient at the field site, with lower diversity observed under acidic (pH <4.5) conditions. Fungal isolates recovered from subsurface sediments, including cultures of the genus Coniochaeta, which were detected in abundance in pyrosequence libraries of site groundwater samples, were shown to reduce nitrate to nitrous oxide. Denitrifying fungal isolates recovered from the site were classified and found to be distributed broadly within the phylum Ascomycota and within a single genus of the Basidiomycota. Potential denitrification rate assays with sediment-groundwater slurries showed the potential for subsurface fungi to reduce nitrate to nitrous oxide under in situ acidic pH conditions. PMID:24389927

Atmospheric volatilization and distribution of (Z)- and (E)-1,3-dichloropropene in field beds with and without plastic covers.

PubMed

Thomas, John E; Allen, L Hartwell; McCormack, Leslie A; Vu, Joseph C; Dickson, Donald W; Ou, Li-Tse

2004-01-01

The fumigant 1,3-dichloropropene (1,3-D) is considered to be a potential replacement for methyl bromide when methyl bromide is phased out in 2005. This study on surface emissions and subsurface diffusion of 1,3-D in a Florida sandy soil was conducted in field beds with or without plastic covers. After injection of the commercial fumigant Telone II by conventional chisels to field beds at 30cm depth which were covered with polyethylene film (PE), virtually impermeable film, or no cover (bare), (Z)- and (E)-1,3-D rapidly diffused upward. Twenty hours after injection, majority of (Z)- and (E)-1,3-D had moved upward from 30 cm depth to the layer of 5-20 cm depth. Downward movement of the two isomers in the beds with or without a plastic cover was not significant. (Z)-1,3-D diffused more rapidly than (E)-1,3-D. Virtually impermeable films (VIF) had a good capacity to retain (Z)- and (E)-1,3-D in soil pore air space. Vapor concentrations of the two isomers in the shallow subsurface of the field bed covered with VIF were greater than that in the two beds covered with polyethylene film (PE) or no cover (bare). In addition, VIF cover provided more uniform distribution of (Z)- and (E)-1,3-D in shallow subsurface than PE cover or no cover. Virtually impermeable film also had a better capability to retard surface emissions of the two isomers from soil in field beds than PE cover or no cover.

Subsurface architecture of Las Bombas volcano circular structure (Southern Mendoza, Argentina) from geophysical studies

NASA Astrophysics Data System (ADS)

Prezzi, Claudia; Risso, Corina; Orgeira, María Julia; Nullo, Francisco; Sigismondi, Mario E.; Margonari, Liliana

2017-08-01

The Plio-Pleistocene Llancanelo volcanic field is located in the south-eastern region of the province of Mendoza, Argentina. This wide back-arc lava plateau, with hundreds of monogenetic pyroclastic cones, covers a large area behind the active Andean volcanic arc. Here we focus on the northern Llancanelo volcanic field, particularly in Las Bombas volcano. Las Bombas volcano is an eroded, but still recognizable, scoria cone located in a circular depression surrounded by a basaltic lava flow, suggesting that Las Bombas volcano was there when the lava flow field formed and, therefore, the lava flow engulfed it completely. While this explanation seems reasonable, the common presence of similar landforms in this part of the field justifies the need to establish correctly the stratigraphic relationship between lava flow fields and these circular depressions. The main purpose of this research is to investigate Las Bombas volcano 3D subsurface architecture by means of geophysical methods. We carried out a paleomagnetic study and detailed topographic, magnetic and gravimetric land surveys. Magnetic anomalies of normal and reverse polarity and paleomagnetic results point to the occurrence of two different volcanic episodes. A circular low Bouguer anomaly was detected beneath Las Bombas scoria cone indicating the existence of a mass deficit. A 3D forward gravity model was constructed, which suggests that the mass deficit would be related to the presence of fracture zones below Las Bombas volcano cone, due to sudden degassing of younger magma beneath it, or to a single phreatomagmatic explosion. Our results provide new and detailed information about Las Bombas volcano subsurface architecture.

Improving National Water Modeling: An Intercomparison of two High-Resolution, Continental Scale Models, CONUS-ParFlow and the National Water Model

NASA Astrophysics Data System (ADS)

Tijerina, D.; Gochis, D.; Condon, L. E.; Maxwell, R. M.

2017-12-01

Development of integrated hydrology modeling systems that couple atmospheric, land surface, and subsurface flow is growing trend in hydrologic modeling. Using an integrated modeling framework, subsurface hydrologic processes, such as lateral flow and soil moisture redistribution, are represented in a single cohesive framework with surface processes like overland flow and evapotranspiration. There is a need for these more intricate models in comprehensive hydrologic forecasting and water management over large spatial areas, specifically the Continental US (CONUS). Currently, two high-resolution, coupled hydrologic modeling applications have been developed for this domain: CONUS-ParFlow built using the integrated hydrologic model ParFlow and the National Water Model that uses the NCAR Weather Research and Forecasting hydrological extension package (WRF-Hydro). Both ParFlow and WRF-Hydro include land surface models, overland flow, and take advantage of parallelization and high-performance computing (HPC) capabilities; however, they have different approaches to overland subsurface flow and groundwater-surface water interactions. Accurately representing large domains remains a challenge considering the difficult task of representing complex hydrologic processes, computational expense, and extensive data needs; both models have accomplished this, but have differences in approach and continue to be difficult to validate. A further exploration of effective methodology to accurately represent large-scale hydrology with integrated models is needed to advance this growing field. Here we compare the outputs of CONUS-ParFlow and the National Water Model to each other and with observations to study the performance of hyper-resolution models over large domains. Models were compared over a range of scales for major watersheds within the CONUS with a specific focus on the Mississippi, Ohio, and Colorado River basins. We use a novel set of approaches and analysis for this comparison to better understand differences in process and bias. This intercomparison is a step toward better understanding how much water we have and interactions between surface and subsurface. Our goal is to advance our understanding and simulation of the hydrologic system and ultimately improve hydrologic forecasts.

Hydrological connectivity: From hillslopes to watersheds

NASA Astrophysics Data System (ADS)

McDonnell, Jeffrey; Ameli, Ali; Coles, Anna

2017-04-01

Research on runoff processes has focused on the differences between the main divisions of runoff partitioning. Indeed, our major advancements in runoff theory have come with new differentiations of various forms of overland flow and subsurface stormflow. These studies of 'how runoff processes are different' have resulted in our current summaries of runoff regimes conceptually (e.g. the Variable Source Area concept) and codified in our models (e.g. TOPMODEL and its derivatives). While such process differentiation was useful as new dominant forms of runoff were "discovered" in different climates with different soils, slope morphologies and vegetation cover continued differentiation does not appear helpful for improved understanding of soil runoff dynamics and streamflow generation. We seem to have exhausted the main list of runoff classes some decades ago, with perhaps the last wave of minor updates to these processes coming in the 1980s and early 1990s in response to isotope tracing demonstrating the importance of stored water and clarifying the differences between soil water velocities and celerities. This talk explores the similarities (and not differences) between all forms of runoff. Our main thesis is that across diverse environments and scales, one key prerequisite for runoff generation exists: connectivity. We will show how the sequence of soil filling and spilling, transmission loss along the flowpath and resulting threshold runoff are all connectivity-based—and we hypothesize, common to all overland and subsurface forms of runoff. We suggest that by asking if 'all runoff processes are the same' this may be a new way to come at improved process measurement, understanding and prediction across diverse regions. We use a connectivity perspective to examine specific questions of: What can we learn about subsurface stormflow from overland flow (and vice versa)? Can we recognize things on the soil surface (where boundary conditions are visible) that may help guide new theory for the subsurface where such soil boundary controls are hidden? Examples are given from hillslope and watershed scales, frozen and unfrozen soils and field-model combinations from sites in the Georgia, South Carolina, Oregon and Saskatchewan.

Palynostratigraphic correlation of the Fort Union formation (Paleocene) in the Wind River Reservation and Waltman Area, Wind River Basin, Wyoming

USGS Publications Warehouse

Nichols, D.J.; Flores, R.M.

1993-01-01

Palynologic samples of the Fort Union Formation (Paleocene) were collected from selected composite measured sections and a drill hole in the Wind River Basin. Intervals studied are in outcrop in the Wind River Reservation in the Shotgun Butte area and near Hudson, Wyoming, and in the subsurface in the Muddy Ridge field. Age determinations were made using the palynostratigraphic zonation originally developed near Waltman, Wyoming, in the northeastern part of the basin. Although parts of the zonation have been called into question by other recent work in the basin, only the basal Paleocene biozone (P1) is in need of modification, and the zonation remains an effective tool for age determination and correlation in these rocks. Age control is sparse in parts of some sections studied, mostly because of a dominance of sandstone and conglomerate facies, but palynostratigraphy permits correlation of the study areas with each other and with the Waltman reference section.Palynology supports the following correlations: The lower unnamed member of the Fort Union Formation in the Shotgun Butte area correlates stratigraphically and chronologically with the lower part of the formation in the subsurface at Muddy Ridge field, with a short interval in the Hudson area, and with the lower and middle parts of the unnamed member in the Waltman area. The Shotgun Member correlates chronologically with the coal-bearing upper part of the Fort Union Formation in the subsurface at Muddy Ridge field and with the upper part of the unnamed member and Waltman Shale Member in the Waltman area. These correlations show that significant coal deposits in the subsurface have little or no expression in outcrop because of changes in facies.

Finding the best windows: An apparent environmental threshold determines which diffuse flows are dominated by subsurface microbes

NASA Astrophysics Data System (ADS)

Olins, H. C.; Rogers, D.; Scholin, C. A.; Preston, C. J.; Vidoudez, C.; Ussler, W.; Pargett, D.; Jensen, S.; Roman, B.; Birch, J. M.; Girguis, P. R.

2014-12-01

Hydrothermal vents are hotspots of microbial primary productivity often described as "windows into the subsurface biosphere." High temperature vents have received the majority of research attention, but cooler diffuse flows are as, if not more, important a source of heat and chemicals to the overlying ocean. We studied patterns of in situ gene expression and co-registered geochemistry in order to 1) describe the diversity and physiological poise of active microbial communities that span thermal and geochemical gradients from active diffuse flow to background vent field seawater, and 2) determine to what extent seawater or subsurface microbes were active throughout this environment. Analyses of multiple metatranscriptomes from 5 geochemically distinct sites (some from samples preserved in situ) show that proximate diffuse flows showed strikingly different transcription profiles. Specifically, caldera background and some diffuse flows were similar, both dominated by seawater-derived Gammaproteobacteria despite having distinct geochemistries. Intra-field community shows evidence of increased primary productivity throughout the entire vent field and not just at individual diffuse flows. In contrast, a more spatially limited, Epsilonproteobacteria-dominated transcription profile from the most hydrothermally-influenced diffuse flow appeared to be driven by the activity of vent-endemic microbes, likely reflecting subsurface microbial activity. We suggest that the microbial activity within many diffuse flow vents is primarily attributable to seawater derived Gammaproteobacterial sulfur oxidizers, while in certain other flows vent-endemic Epsilonproteobactiera are most active. These data reveal a diversity in microbial activity at diffuse flows that has not previously been recognized, and reshapes our thinking about the relative influence that different microbial communities may have on local processes (such as primary production) and potentially global biogeochemical cycles.

The Subsurface Flow and Transport Laboratory: A New Department of Energy User's Facility for Intermediate-Scale Experimentation

NASA Astrophysics Data System (ADS)

Wietsma, T. W.; Oostrom, M.; Foster, N. S.

2003-12-01

Intermediate-scale experiments (ISEs) for flow and transport are a valuable tool for simulating subsurface features and conditions encountered in the field at government and private sites. ISEs offer the ability to study, under controlled laboratory conditions, complicated processes characteristic of mixed wastes and heterogeneous subsurface environments, in multiple dimensions and at different scales. ISEs may, therefore, result in major cost savings if employed prior to field studies. A distinct advantage of ISEs is that researchers can design physical and/or chemical heterogeneities in the porous media matrix that better approximate natural field conditions and therefore address research questions that contain the additional complexity of processes often encountered in the natural environment. A new Subsurface Flow and Transport Laboratory (SFTL) has been developed for ISE users in the Environmental Spectroscopy & Biogeochemistry Facility in the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory (PNNL). The SFTL offers a variety of columns and flow cells, a new state-of-the-art dual-energy gamma system, a fully automated saturation-pressure apparatus, and analytical equipment for sample processing. The new facility, including qualified staff, is available for scientists interested in collaboration on conducting high-quality flow and transport experiments, including contaminant remediation. Close linkages exist between the SFTL and numerical modelers to aid in experimental design and interpretation. This presentation will discuss the facility and outline the procedures required to submit a proposal to use this unique facility for research purposes. The W. R. Wiley Environmental Molecular Sciences Laboratory, a national scientific user facility, is sponsored by the U.S. Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanco-Rey, M.; Donostia International Physics Center; Tremblay, J. C.

2015-04-21

Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emergemore » from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ{sup −1} are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.« less

Soil Moisture Dynamics in the Shallow Subsurface Near the Land/Atmospheric Interface- Challenges and New Research Approaches (Invited)

NASA Astrophysics Data System (ADS)

Illangasekare, T. H.; Smits, K. M.; Trautz, A.; Rice, A. K.; Cihan, A.; Davarzani, H.

2013-12-01

SSoil moisture processes in the subsurface/near-land-surface, play a crucial role in the hydrologic cycle and global water budget. This zone is subject to both natural and human induced disturbances, resulting in continually changing soil structure and hydraulic, thermal, and mechanical properties. Understanding of the dynamics of soil moisture distribution in this zone is of interest in various applications in hydrology such as land-atmospheric interaction, soil evaporation and evapotranspiration, as well as emerging problems on assessing the risk of leakage of sequestrated CO2 from deep geologic formations to the shallow subsurface, and potential leakage of methane to the atmosphere in shale gas development that contributes to global warming. Shallow subsurface soil moisture is highly influenced by diurnal temperature variations, evaporation/condensation, precipitation and liquid water and water vapor flow, all of which are strongly coupled. Modeling studies, have shown that soil moisture in this zone is highly sensitive to the heat and mass flux boundary conditions at the land surface. Hence, approximation of these boundary conditions without properly incorporating complex feedback between the land and the atmospheric boundary layer are expected to result in significant errors. Even though considerable knowledge exists on how soil moisture changes in response to the flux and energy boundary conditions, emerging problems involving land atmospheric interactions require the quantification of soil moisture variability at higher spatial and temporal resolutions than what is needed in traditional applications in soil physics and vadose zone hydrology. These factors lead to many modeling challenges, primarily of which is the issue of up-scaling. It is our contention that knowledge that will contribute to both improving our understanding of the fundamental processes and practical problem solutions cannot be obtained using only field data. Basic to this limitation is the inability to make field measurements at very fine scales at high temporal resolutions. Also, as the natural boundary conditions at the land/atmospheric interface are not controllable in the field, even in pilot scale studies, the developed theories and models cannot be validated for a diversity of conditions that could be expected. As an alternative, we propose an innovative testing approach that couples a low velocity boundary layer climate wind tunnel to intermediate scale porous media tanks. Intermediate scale testing using soil tanks packed to represent different heterogeneous test configurations provides an attractive and cost effective alternative to investigate a class of problems involving the shallow unsaturated zone. In this talk, we will present examples of studies we have conducted in a hierarchy of test systems, including the intermediate scale. The advantages and limitations of testing at this scale are discussed using these examples. The features and capabilities of newly developed test systems are presented with the goal of exploring opportunities to use them to study some of the challenging multi-scale problems in the near surface unsaturated zone.

Directional phytoscreening: contaminant gradients in trees for plume delineation.

PubMed

Limmer, Matt A; Shetty, Mikhil K; Markus, Samantha; Kroeker, Ryan; Parker, Beth L; Martinez, Camilo; Burken, Joel G

2013-08-20

Tree sampling methods have been used in phytoscreening applications to delineate contaminated soil and groundwater, augmenting traditional investigative methods that are time-consuming, resource-intensive, invasive, and costly. In the past decade, contaminant concentrations in tree tissues have been shown to reflect the extent and intensity of subsurface contamination. This paper investigates a new phytoscreening tool: directional tree coring, a concept originating from field data that indicated azimuthal concentrations in tree trunks reflected the concentration gradients in the groundwater around the tree. To experimentally test this hypothesis, large diameter trees were subjected to subsurface contaminant concentration gradients in a greenhouse study. These trees were then analyzed for azimuthal concentration gradients in aboveground tree tissues, revealing contaminant centroids located on the side of the tree nearest the most contaminated groundwater. Tree coring at three field sites revealed sufficiently steep contaminant gradients in trees reflected nearby groundwater contaminant gradients. In practice, trees possessing steep contaminant gradients are indicators of steep subsurface contaminant gradients, providing compass-like information about the contaminant gradient, pointing investigators toward higher concentration regions of the plume.

Compositional and Textural Analysis of Maar-Diatreme Volcanic Deposits at Hopi Buttes Volcanic Field (AZ) Using GigaPan Panoramic and Thermal Infrared Imagery

NASA Astrophysics Data System (ADS)

Lee, R.; Graettinger, A. H.; Weinell, M.; Hughes, C. G.

2016-12-01

Basaltic maar-diatreme volcanoes are produced when rising magma interacts with groundwater and produces a maar crater at the ground surface. This crater is underlain by a diatreme, a downward-tapering conical structure filled with a mixture of fragments of intruded magma, fractured host rock, and clasts recycled through repeated discrete subsurface explosions. The debris of the diatreme records the mixing processes caused by subsurface explosions and is the source for ejected material that forms maar tephra rings. Determining the variable depths and lateral locations of these explosions and how energy is dissipated in the subsurface is critical to understanding how maar-diatreme eruptions progress. The Hopi Buttes Volcanic Field (HBVF) in the Navajo Nation, Arizona, USA, contains several diatremes and incised tephra rings with heterolithic clasts 10 mm - 10 m in size, and are well-exposed near-vertical to vertical outcrops. Our ability to measure the length scales and distribution of textures produced by subsurface explosions in these diatremes is limited by the physical accessibility of the exposures, due to both the verticality of the outcrops and the cultural sensitivity of the site. Quantifying the number and locations of explosions is dependent on our ability to investigate the full diatreme outcrop, and not just what can be accessed through traditional field observations. We present a novel field and computer-based technique for both quantitatively and qualitatively characterizing the composition and texture of maar-diatreme deposits in vertical outcrops. This technique uses a combination of field-collected multispectral thermal infrared (TIR) image data and visible wavelength GigaPan imagery to characterize the compositional and textural variations over a whole outcrop. To increase the spatial and spectral resolution of the TIR data, a super-resolution technique will be applied. The technique provides a simple and efficient method to augment the study of the maar-diatreme deposits at HBVF. In addition to contributing to a better understanding of the formation processes of maar-diatreme deposits around the world, the technique also shows great promise for studies involving other types of large outcrops and geologic structures.

Subsurface safety valves: safety asset or safety liability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busch, J.M.; Llewelyn, D.C.G.; Policky, B.J.

1983-10-01

This paper summarizes the methods used to compare the risk of a blowout for a well completed with a subsurface safety valve (SSSV) vs. a completion without an SSSV. These methods, which could be applied to any field, include a combination of SSSV reliability and conventional risk analyses. The Kuparuk River Unit Working Interest Owners recently formed a group to examine the risks associated with installing and maintaining SSSV's in the Kuparuk field. The group was charged with answering the question: ''Assuming Kuparuk field operating conditions, are SSSV's a safety asset, or do numerous operating and maintenance procedures make themmore » a safety liability.'' The results indicate that for the Kuparuk River Unit, an SSSV becomes a safety liability when the mean time between SSSV failures is less than one year. Since current SSSV mean time to failure (MTTF) at Kuparuk is approximately 1000 days, they are considered a safety asset.« less

Electromagnetic signal penetration in a planetary soil simulant: Estimated attenuation rates using GPR and TDR in volcanic deposits on Mount Etna

NASA Astrophysics Data System (ADS)

Lauro, S. E.; Mattei, E.; Cosciotti, B.; Di Paolo, F.; Arcone, S. A.; Viccaro, M.; Pettinelli, E.

2017-07-01

Ground-penetrating radar (GPR) is a well-established geophysical terrestrial exploration method and has recently become one of the most promising for planetary subsurface exploration. Several future landing vehicles like EXOMARS, 2020 NASA ROVER, and Chang'e-4, to mention a few, will host GPR. A GPR survey has been conducted on volcanic deposits on Mount Etna (Italy), considered a good analogue for Martian and Lunar volcanic terrains, to test a novel methodology for subsoil dielectric properties estimation. The stratigraphy of the volcanic deposits was investigated using 500 MHz and 1 GHz antennas in two different configurations: transverse electric and transverse magnetic. Sloping discontinuities have been used to estimate the loss tangents of the upper layer of such deposits by applying the amplitude-decay and frequency shift methods and approximating the GPR transmitted signal by Gaussian and Ricker wavelets. The loss tangent values, estimated using these two methodologies, were compared and validated with those retrieved from time domain reflectometry measurements acquired along the radar profiles. The results show that the proposed analysis, together with typical GPR methods for the estimation of the real part of permittivity, can be successfully used to characterize the electrical properties of planetary subsurface and to define some constraints on its lithology of the subsurface.

JUICE: complementarity of the payload in adressing the mission science objectives

NASA Astrophysics Data System (ADS)

Titov, Dmitri; Barabash, Stas; Bruzzone, Lorenzo; Dougherty, Michele; Erd, Christian; Fletcher, Leigh; Gare, Philippe; Gladstone, Randall; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Langevin, Yves; Palumbo, Pasquale; Piccioni, Giuseppe; Wahlund, Jan-Erik

2014-05-01

JUpiter ICy moons Explorer (JUICE) will perform detailed investigations of Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. The overarching theme for JUICE is: The emergence of habitable worlds around gas giants. At Ganymede, the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions will be elucidated. JUICE will study the moons' interactions with the magnetosphere, gravitational coupling and long-term tidal evolution of the Galilean satellites. JUICE highly capable scientific payload includes 10 state-of-the-art instruments onboard the spacecraft plus one experiment that uses the spacecraft telecommunication system with ground-based radio telescopes. The remote sensing package includes a high-resolution multi-band visible imager (JANUS) and spectro-imaging capabilities from the ultraviolet to the sub-millimetre wavelengths (MAJIS, UVS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the surface and subsurface of the moons, and a radio science experiment (3GM) to probe the atmospheres of Jupiter and its satellites and to perform measurements of the gravity fields. An in situ package comprises a powerful particle environment package (PEP), a magnetometer (J-MAG) and a radio and plasma wave instrument (RPWI), including electric fields sensors and a Langmuir probe. An experiment (PRIDE) using ground-based Very-Long-Baseline Interferometry (VLBI) will provide precise determination of the moons ephemerides. The instruments will work together to achieve mission science objectives that otherwise cannot be achieved by a single experiment. For instance, joint J-MAG, 3GM, GALA and JANUS observations would constrain thickness of the ice shell, ocean depth and conductivity. SWI, 3GM and UVS would complement each other in the temperature sounding of the Jupiter atmosphere. The complex coupling between magnetosphere and atmosphere of Jupiter will be jointly studied by combination of aurora imaging (UVS, MAJIS, JANUS) and plasma and fields measurements (J-MAG, RPWI, PEP). The talk will give an overview of the JUICE payload focusing on complementarity and synergy between the experiments.

Electrical Resistivity Imaging

EPA Science Inventory

Electrical resistivity imaging (ERI) is a geophysical method originally developed within the mining industry where it has been used for decades to explore for and characterize subsurface mineral deposits. It is one of the oldest geophysical methods with the first documented usag...

Development of Hand-Held Thermographic Inspection Technologies

DOT National Transportation Integrated Search

2009-09-01

This study explored the application of hand-held thermographic cameras for the detection of subsurface delaminations in concrete bridges. The goal of the research was to provide maintenance and inspection personnel with an effective tool for detectin...

Development of hand-held thermographic inspection technologies.

DOT National Transportation Integrated Search

2009-09-01

This study explored the application of hand-held thermographic cameras for the detection of subsurface delaminations in concrete : bridges. The goal of the research was to provide maintenance and inspection personnel with an effective tool for detect...

43 CFR 3252.11 - What environmental requirements must I meet when conducting exploration operations?

Code of Federal Regulations, 2011 CFR

2011-10-01

... operations in a manner that: (1) Protects the quality of surface and subsurface waters, air, and other natural resources, including wildlife, soil, vegetation, and natural history; (2) Protects the quality of...

Exploration computer applications to primary dispersion halos: Kougarok tin prospect, Seward Peninsula, Alaska, USA

USGS Publications Warehouse

Reid, Jeffrey C.

1989-01-01

Computer processing and high resolution graphics display of geochemical data were used to quickly, accurately, and efficiently obtain important decision-making information for tin (cassiterite) exploration, Seward Peninsula, Alaska (USA). Primary geochemical dispersion patterns were determined for tin-bearing intrusive granite phases of Late Cretaceous age with exploration bedrock lithogeochemistry at the Kougarok tin prospect. Expensive diamond drilling footage was required to reach exploration objectives. Recognition of element distribution and dispersion patterns was useful in subsurface interpretation and correlation, and to aid location of other holes.

System concepts and enabling technologies for an ESA low-cost mission to Jupiter / Europa

NASA Astrophysics Data System (ADS)

Renard, P.; Koeck, C.; Kemble, Steve; Atzei, Alessandro; Falkner, Peter

2004-11-01

The European Space Agency is currently studying the Jovian Minisat Explorer (JME), as part of its Technology Reference Studies (TRS), used for its development plan of technologies enabling future scientific missions. The JME focuses on the exploration of the Jovian system and particularly of Europa. The Jupiter Minisat Orbiter (JMO) study concerns the first mission phase of JME that counts up to three missions using pairs of minisats. The scientific objectives are the investigation of Europa's global topography, the composition of its (sub)surface and the demonstration of existence of a subsurface ocean below its icy crust. The present paper describes the candidate JMO system concept, based on a Europa Orbiter (JEO) supported by a communications relay satellite (JRS), and its associated technology development plan. It summarizes an analysis performed in 2004 jointly by ESA and the EADS-Astrium Company in the frame of an industrial technical assistance to ESA.

Development of ultrastable filters and lasers for solar seismology

NASA Technical Reports Server (NTRS)

Rust, D. M.; Kunski, R.; Cohn, R. F.

1986-01-01

The Stable Solar Analyzer is a recently developed instrument for the measurement of solar magnetic fields and surface velocities that is being employed at the U.S. National Solar Observatory to study the subsurface convection cells of the sun and the structure of surface and subsurface magnetic fields. The Analyzer is expected to ultimately be flown aboard such spacecraft as the ESA/NASA Solar and Heliospheric Observatory. This instrument is based on a crystalline lithium niobate Fabry-Perot filter that is used in conjunction with a stabilized laser that furnishes an absolute wavelength reference; this laser Fabry-Perot combination has achieved wavelength stabilities of the order of 2 parts in 10 to the 10th, over a six-hour interval.

Mars Radar Opens a Planet's Third Dimension

NASA Technical Reports Server (NTRS)

2008-01-01

Radar sounder instruments orbiting Mars have looked beneath the Martian surface and opened up the third dimension for planetary exploration. The technique's success is prompting scientists to think of all the other places in the Solar System where they would like to use radar sounders.

The first radar sounder at Mars was the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on the European Space Agency's Mars Express Orbiter. It has been joined by the complementary Shallow Subsurface Radar (SHARAD), operating at a different wavelength aboard NASA's Mars Reconnaissance Orbiter. The data in this animation are from SHARAD.

WISDOM measurements in a cold artificial and controlled environment

NASA Astrophysics Data System (ADS)

Dechambre, M.; Saintenoy, A.; Ciarletti, V.; Biancheri-Astier, M.; Costard, F.; Hassen-Khodja, R.

2011-10-01

The WISDOM (500MHz - 3GHz) GPR is one of the instruments that have been selected as part of the Pasteur payload of ESA's 2018 ExoMars Rover mission. One of the main scientific objectives of the mission is to characterize the nature of the shallow sub-surface on Mars and WISDOM has been designed to explore the first ~ 3 meters of the subsurface with a vertical resolution of a few centimetres. Full polarimetric measurements in cold artificial and controlled conditions have been performed by the prototype to illustrate and quantify the instrument performance. Preliminary results are presented.

Interactive client side data visualization with d3.js

NASA Astrophysics Data System (ADS)

Rodzianko, A.; Versteeg, R.; Johnson, D. V.; Soltanian, M. R.; Versteeg, O. J.; Girouard, M.

2015-12-01

Geoscience data associated with near surface research and operational sites is increasingly voluminous and heterogeneous (both in terms of providers and data types - e.g. geochemical, hydrological, geophysical, modeling data, of varying spatiotemporal characteristics). Such data allows scientists to investigate fundamental hydrological and geochemical processes relevant to agriculture, water resources and climate change. For scientists to easily share, model and interpret such data requires novel tools with capabilities for interactive data visualization. Under sponsorship of the US Department of Energy, Subsurface Insights is developing the Predictive Assimilative Framework (PAF): a cloud based subsurface monitoring platform which can manage, process and visualize large heterogeneous datasets. Over the last year we transitioned our visualization method from a server side approach (in which images and animations were generated using Jfreechart and Visit) to a client side one that utilizes the D3 Javascript library. Datasets are retrieved using web service calls to the server, returned as JSON objects and visualized within the browser. Users can interactively explore primary and secondary datasets from various field locations. Our current capabilities include interactive data contouring and heterogeneous time series data visualization. While this approach is very powerful and not necessarily unique, special attention needs to be paid to latency and responsiveness issues as well as to issues as cross browser code compatibility so that users have an identical, fluid and frustration-free experience across different computational platforms. We gratefully acknowledge support from the US Department of Energy under SBIR Award DOE DE-SC0009732, the use of data from the Lawrence Berkeley National Laboratory (LBNL) Sustainable Systems SFA Rifle field site and collaboration with LBNL SFA scientists.

Applying Reactive Barrier Technology to Enhance Microbially-mediated Denitrification during Managed Aquifer Recharge

NASA Astrophysics Data System (ADS)

Beganskas, S.; Weir, W. B.; Harmon, R. E.; Gorski, G.; Fisher, A. T.; Saltikov, C.; Young, K. S.; Runneals, D.; Teo, E. K.; Stoneburner, B.; Hernandez, J.

2015-12-01

We are running field experiments to observe and quantify microbially-mediated water quality improvement via denitrification during infiltration in the shallow subsurface. Nitrate is a pervasive groundwater contaminant, and nitrate removal through denitrification can occur during infiltration in natural and anthropogenic systems, including during managed aquifer recharge (MAR). The rate of denitrification can vary depending on factors such as infiltration rate; previous work suggests that denitrification rates can increase monotonically with infiltration rates until reaching a critical threshold. We are performing controlled field tests of variables that affect denitrification rate, including sampling to link water chemistry changes to microbial ecology and activity. This study explores how microbial activity and denitrification rates respond to different infiltration rates and the presence or absence of a reactive material (wood chips, a carbon source). We are conducting four two-week-long tests, each under different conditions. For each test, we measure bulk infiltration rate (the sum of lateral and vertical infiltration), vertical infiltration rate using heat as a tracer, and water level. We collect surface and subsurface water samples daily, and we collect soil samples at the start and end of each test. For each water sample, we are measuring NO3-, NO2-, NH3, DOC, and N and O isotopes in nitrate. Soil samples will be tested for grain size, total C/N, and the presence of microbiological genes associated with denitrification. These results will expand our knowledge of the conditions under which denitrification occurs by implicating specific microorganisms and physical infiltration parameters. Our design has the potential for additional experimentation with variables that impact water chemistry during infiltration. This study has broad applications for designing MAR systems that effectively improve water supply and water quality.

On the value of incorporating spatial statistics in large-scale geophysical inversions: the SABRe case

NASA Astrophysics Data System (ADS)

Kokkinaki, A.; Sleep, B. E.; Chambers, J. E.; Cirpka, O. A.; Nowak, W.

2010-12-01

Electrical Resistance Tomography (ERT) is a popular method for investigating subsurface heterogeneity. The method relies on measuring electrical potential differences and obtaining, through inverse modeling, the underlying electrical conductivity field, which can be related to hydraulic conductivities. The quality of site characterization strongly depends on the utilized inversion technique. Standard ERT inversion methods, though highly computationally efficient, do not consider spatial correlation of soil properties; as a result, they often underestimate the spatial variability observed in earth materials, thereby producing unrealistic subsurface models. Also, these methods do not quantify the uncertainty of the estimated properties, thus limiting their use in subsequent investigations. Geostatistical inverse methods can be used to overcome both these limitations; however, they are computationally expensive, which has hindered their wide use in practice. In this work, we compare a standard Gauss-Newton smoothness constrained least squares inversion method against the quasi-linear geostatistical approach using the three-dimensional ERT dataset of the SABRe (Source Area Bioremediation) project. The two methods are evaluated for their ability to: a) produce physically realistic electrical conductivity fields that agree with the wide range of data available for the SABRe site while being computationally efficient, and b) provide information on the spatial statistics of other parameters of interest, such as hydraulic conductivity. To explore the trade-off between inversion quality and computational efficiency, we also employ a 2.5-D forward model with corrections for boundary conditions and source singularities. The 2.5-D model accelerates the 3-D geostatistical inversion method. New adjoint equations are developed for the 2.5-D forward model for the efficient calculation of sensitivities. Our work shows that spatial statistics can be incorporated in large-scale ERT inversions to improve the inversion results without making them computationally prohibitive.

Papua New Guinea MT: Looking where seismic is blind

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoversten, G.M.

1996-11-01

Hydrocarbon exploration in the Papuan fold belt is made extremely difficult by mountainous terrain, equatorial jungle and thick karstified Miocene limestones at the surface. The high-velocity karstified limestones at or near the surface often render the seismic technique useless for imaging the subsurface. In such areas magnetotellurics (MT) provides a valuable capability for mapping subsurface structure. Numerical and field data examples are presented which demonstrate the severity of the 1D errors and the improvements in accuracy which can be achieved using a 2D inverse solution. Two MT lines over adjacent anticlines, both with well control and seismic data, are usedmore » to demonstrate the application of 1D and 2D inversions for structural models. The example over the Hides anticline illustrates a situation where 1D inversion of either TE or TM mode provides essentially the same depth to base of Darai as 2D inversion of both TE and TM. The example over the Angore anticline illustrates the inadequacy of 1D inversion in structurally complex geology complicated by electrical statics. Four MT lines along the Angore anticline have been interpreted using 2D inversion. Three-dimensional modelling has been used to simulate 3D statics in an otherwise 2D earth. These data were used to test the Groom-Bailey (GB) decomposition for possible benefits in reducing static effects and estimating geoelectric strike in the Papua New Guinea (PNG) field data. It has been found that the GB decomposition can provide improved regional 2D strike estimates in 3D contaminated data. However, in situations such as PNG, where the regional 2D strike is well established and hence can be fixed, the GB decomposition provides apparent resistivities identical to those simply rotated to strike.« less

Pitfalls in velocity analysis for strongly contrasting, layered media - Example from the Chalk Group, North Sea

NASA Astrophysics Data System (ADS)

Montazeri, Mahboubeh; Uldall, Anette; Moreau, Julien; Nielsen, Lars

2018-02-01

Knowledge about the velocity structure of the subsurface is critical in key seismic processing sequences, for instance, migration, depth conversion, and construction of initial P- and S-wave velocity models for full-waveform inversion. Therefore, the quality of subsurface imaging is highly dependent upon the quality of the seismic velocity analysis. Based on a case study from the Danish part of the North Sea, we show how interference caused by multiples, converted waves, and thin-layer effects may lead to incorrect velocity estimation, if such effects are not accounted for. Seismic wave propagation inside finely layered reservoir rocks dominated by chalk is described by two-dimensional finite-difference wave field simulation. The rock physical properties used for the modeling are based on an exploration well from the Halfdan field in the Danish sector of the North Sea. The modeling results are compared to seismic data from the study area. The modeling shows that interference of primaries with multiples, converted waves and thin-bed effects can give rise to strong anomalies in standard velocity analysis plots. Consequently, root-mean-square (RMS) velocity profiles may be erroneously picked. In our study area, such mis-picking can introduce errors in, for example, the thickness estimation of the layers near the base of the studied sedimentary strata by 11% to 26%. Tests show that front muting and bandpass filtering cannot significantly improve the quality of velocity analysis in our study. However, we notice that spiking deconvolution applied before velocity analysis may to some extent reduce the impact of interference and, therefore, reduce the risk of erroneous picking of the velocity function.

A locally conservative stabilized continuous Galerkin finite element method for two-phase flow in poroelastic subsurfaces

NASA Astrophysics Data System (ADS)

Deng, Q.; Ginting, V.; McCaskill, B.; Torsu, P.

2017-10-01

We study the application of a stabilized continuous Galerkin finite element method (CGFEM) in the simulation of multiphase flow in poroelastic subsurfaces. The system involves a nonlinear coupling between the fluid pressure, subsurface's deformation, and the fluid phase saturation, and as such, we represent this coupling through an iterative procedure. Spatial discretization of the poroelastic system employs the standard linear finite element in combination with a numerical diffusion term to maintain stability of the algebraic system. Furthermore, direct calculation of the normal velocities from pressure and deformation does not entail a locally conservative field. To alleviate this drawback, we propose an element based post-processing technique through which local conservation can be established. The performance of the method is validated through several examples illustrating the convergence of the method, the effectivity of the stabilization term, and the ability to achieve locally conservative normal velocities. Finally, the efficacy of the method is demonstrated through simulations of realistic multiphase flow in poroelastic subsurfaces.

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

DOEpatents

Ramirez, Abelardo L.; Cooper, John F.; Daily, William D.

1996-01-01

This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination.

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

DOEpatents

Ramirez, A.L.; Cooper, J.F.; Daily, W.D.

1996-02-27

This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination. 1 fig.

Effect of Climate Extremes, Seasonal Change, and Agronomic Practices on Measured Evapotranspiration and CO2 Exchange in Sacramento-San Joaquin River Delta Alfalfa Fields

NASA Astrophysics Data System (ADS)

Clay, J.; Kent, E. R.; Leinfelder-Miles, M.; Paw U, K. T.; Little, C.; Lambert, J. J.

2017-12-01

Evapotranspiration and CO2 exchange was measured in five alfalfa fields in the Sacramento-San Joaquin River Delta region from 2016 to 2017 using eddy covariance and surface renewal methods. Seasonal changes of evapotranspiration and CO2 fluxes were compared between 2016, a drought year, and 2017, a high rainfall year. Additionally, changes in evapotranspiration and CO2 flux were investigated across various agronomic considerations, such as irrigation methods (border-check flood and sub-surface), stand life, and herbicide programs. Components of the energy balance, including net radiation, latent heat, ground heat flux, and sensible heat, were evaluated considering correlations to wind speed measured by three sonic anemometers, irrigation frequency, and crop cutting cycle. Comparisons between two different types of radiometers were also carried out. Under drought conditions, we observed higher amounts of evapotranspiration in a field having a stand life of less than two years of age compared to older stands, and in a sub-surface irrigated field compared to flood irrigated fields.

Microbial Fossils from Terrestrial Subsurface Hydrothermal Environments: Examples and Implications for Mars

NASA Technical Reports Server (NTRS)

Hofmann, Beda A.; Farmer, Jack; Chang, Sherwood (Technical Monitor)

1997-01-01

The recognition of biological signatures in ancient epithermal deposits has special relevance for studies of early blaspheme evolution and in exploring for past life on Mars. Recently, proposals for the existence of an extensive subsurface blaspheme on Earth, dominated by chemoautotrophic microbial life, has gained prominence. However, reports of fossilized microbial remains, or biosedimentary structures (e.g. stromatolites) from the deposits of ancient subsurface systems, are rare. Microbial preservation is favoured where high population densities co-exist with rapid mineral precipitation. Near-surface epithetical systems with strong gradients in temperature and redox are good candidates for the abundant growth and fossilization of microorganisms, and are also favorable environments for the precipitation of ore minerals. Therefore, we might expect microbial remain, to be particularly well preserved in various kinds of hydrothermal and diagenetic mineral precipitates that formed below the upper temperature limit for life (approx. 120 C).

Comparison of precursor infiltration into polymer thin films via atomic layer deposition and sequential vapor infiltration using in-situ quartz crystal microgravimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padbury, Richard P.; Jur, Jesse S., E-mail: jsjur@ncsu.edu

Previous research exploring inorganic materials nucleation behavior on polymers via atomic layer deposition indicates the formation of hybrid organic–inorganic materials that form within the subsurface of the polymer. This has inspired adaptations to the process, such as sequential vapor infiltration, which enhances the diffusion of organometallic precursors into the subsurface of the polymer to promote the formation of a hybrid organic–inorganic coating. This work highlights the fundamental difference in mass uptake behavior between atomic layer deposition and sequential vapor infiltration using in-situ methods. In particular, in-situ quartz crystal microgravimetry is used to compare the mass uptake behavior of trimethyl aluminummore » in poly(butylene terephthalate) and polyamide-6 polymer thin films. The importance of trimethyl aluminum diffusion into the polymer subsurface and the subsequent chemical reactions with polymer functional groups are discussed.« less

Subsurface Ice Probe

NASA Technical Reports Server (NTRS)

Hecht, Michael; Carsey, Frank

2005-01-01

The subsurface ice probe (SIPR) is a proposed apparatus that would bore into ice to depths as great as hundreds of meters by melting the ice and pumping the samples of meltwater to the surface. Originally intended for use in exploration of subsurface ice on Mars and other remote planets, the SIPR could also be used on Earth as an alternative to coring, drilling, and melting apparatuses heretofore used to sample Arctic and Antarctic ice sheets. The SIPR would include an assembly of instrumentation and electronic control equipment at the surface, connected via a tether to a compact assembly of boring, sampling, and sensor equipment in the borehole (see figure). Placing as much equipment as possible at the surface would help to attain primary objectives of minimizing power consumption, sampling with high depth resolution, and unobstructed imaging of the borehole wall. To the degree to which these requirements would be satisfied, the SIPR would offer advantages over the aforementioned ice-probing systems.

The InSight Mars Lander and Its Effect on the Subsurface Thermal Environment

NASA Astrophysics Data System (ADS)

Siegler, Matthew A.; Smrekar, Suzanne E.; Grott, Matthias; Piqueux, Sylvain; Mueller, Nils; Williams, Jean-Pierre; Plesa, Ana-Catalina; Spohn, Tilman

2017-10-01

The 2018 InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Mission has the mission goal of providing insitu data for the first measurement of the geothermal heat flow of Mars. The Heat Flow and Physical Properties Package (HP3) will take thermal conductivity and thermal gradient measurements to approximately 5 m depth. By necessity, this measurement will be made within a few meters of the lander. This means that thermal perturbations from the lander will modify local surface and subsurface temperature measurements. For HP3's sensitive thermal gradient measurements, this spacecraft influence will be important to model and parameterize. Here we present a basic 3D model of thermal effects of the lander on its surroundings. Though lander perturbations significantly alter subsurface temperatures, a successful thermal gradient measurement will be possible in all thermal conditions by proper (>3 m depth) placement of the heat flow probe.

Dielectric properties of Jovian satellite ice analogs for subsurface radar exploration: A review

NASA Astrophysics Data System (ADS)

Pettinelli, Elena; Cosciotti, Barbara; Di Paolo, Federico; Lauro, Sebastian Emanuel; Mattei, Elisabetta; Orosei, Roberto; Vannaroni, Giuliano

2015-09-01

The first European mission dedicated to the exploration of Jupiter and its icy moons (JUpiter ICy moons Explorer—JUICE) will be launched in 2022 and will reach its final destination in 2030. The main goals of this mission are to understand the internal structure of the icy crusts of three Galilean satellites (Europa, Ganymede, and Callisto) and, ultimately, to detect Europa's subsurface ocean, which is believed to be the closest to the surface among those hypothesized to exist on these moons. JUICE will be equipped with the 9 MHz subsurface-penetrating radar RIME (Radar for Icy Moon Exploration), which is designed to image the ice down to a depth of 9 km. Moreover, a parallel mission to Europa, which will host onboard REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface) equipped with 9MHz and 60MHz antennas, has been recently approved by NASA. The success of these experiments strongly relies on the accurate prediction of the radar performance and on the optimal processing and interpretation of radar echoes that, in turn, depend on the dielectric properties of the materials composing the icy satellite crusts. In the present review we report a complete range of potential ice types that may occur on these icy satellites to understand how they may affect the results of the proposed missions. First, we discuss the experimental results on pure and doped water ice in the framework of the Jaccard theory, highlighting the critical aspects in terms of a lack of standard laboratory procedures and inconsistency in data interpretation. We then describe the dielectric behavior of extraterrestrial ice analogs like hydrates and icy mixtures, carbon dioxide ice and ammonia ice. Building on this review, we have selected the most suitable data to compute dielectric attenuation, velocity, vertical resolution, and reflection coefficients for such icy moon environments, with the final goal being to estimate the potential capabilities of the radar missions as a function of the frequency and temperature ranges of interest for the subsurface sounders. We present the different subsurface scenarios and associated radar signal attenuation models that have been proposed so far to simulate the structure of the crust of Europa and discuss the physical and geological nature of various dielectric targets potentially detectable with RIME. Finally, we briefly highlight several unresolved issues that should be addressed, in near future, to improve our capability to produce realistic electromagnetic models of icy moon crusts. The present review is of interest for the geophysical exploration of all solar system bodies, including the Earth, where ice can be present at the surface or at relatively shallow depths.

The DESMEX Project - Deep Electromagnetic Sounding for Mineral EXploration

NASA Astrophysics Data System (ADS)

Meyer, U.; Becken, M.; Stolz, R.; Nittinger, C.; Cherevatova, M.; Siemon, B.; Martin, T.; Petersen, H.; Steuer, A.

2017-12-01

The DESMEX project (Deep Electromagnetic Sounding for Mineral Exploration) aims to develop independent semi-airborne frequency domain systems for mineral exploration down to depths of 1 km and deeper. Two different helicopter-towed systems are being designed and tested using source installations on ground. One system uses among other equipment conventional three axis induction coils, a 3D-fluxgate and a high precision inertial motion unit. The use of the two different magnetometers allows to record data in a broad frequency range from 1 Hz to 10 kHz. The second system uses a newly developed SQUID-based sensing system of a similar frequency range and a self made inertial motion unit. Horizontal electric dipole transmitters provided by the Leibniz Institute for Applied Geophysics in Hannover and the Institute of Geophysics and Meteorology of the University in Cologne are used as ground based sources. First system tests showed a good performance of both systems with general noise levels below 50 pT/root(Hz). Test flights above the common survey area proved that the desired depth of investigation can be achieved and that the data is consistent with the subsurface conductivity structures. In order to verify the data acquired from the newly developed system at shallow depths and to provide a better starting model for later inversion calculations helicopter borne frequency domain electromagnetics has been acquired and fully processed over the test site Schleiz - Greiz in Germany. To further relate the subsurface conductivity models to the subsurface geology and mineralogy, petrophysical investigations have been performed on rock samples from the site of investigation and analogue samples.

Site characterization at Groningen gas field area through joint surface-borehole H/V analysis

NASA Astrophysics Data System (ADS)

Spica, Zack J.; Perton, Mathieu; Nakata, Nori; Liu, Xin; Beroza, Gregory C.

2018-01-01

A new interpretation of the horizontal to vertical (H/V) spectral ratio in terms of the Diffuse Field Assumption (DFA) has fuelled a resurgence of interest in that approach. The DFA links H/V measurements to Green's function retrieval through autocorrelation of the ambient seismic field. This naturally allows for estimation of layered velocity structure. In this contribution, we further explore the potential of H/V analysis. Our study is facilitated by a distributed array of surface and co-located borehole stations deployed at multiple depths, and by detailed prior information on velocity structure that is available due to development of the Groningen gas field. We use the vertical distribution of H/V spectra recorded at discrete depths inside boreholes to obtain shear wave velocity models of the shallow subsurface. We combine both joint H/V inversion and borehole interferometry to reduce the non-uniqueness of the problem and to allow faster convergence towards a reliable velocity model. The good agreement between our results and velocity models from an independent study validates the methodology, demonstrates the power of the method, but more importantly provides further constraints on the shallow velocity structure, which is an essential component of integrated hazard assessment in the area.

Investigating the complex structural integrity of the Zeit Bay Field, Gulf of Suez, Egypt, using interpretation of 3D seismic reflection data

NASA Astrophysics Data System (ADS)

Afife, M.; Salem, M.; Aziz, M. Abdel

2017-07-01

Zeit Bay Field is one of the most important oil-bearing fields in the Gulf of Suez, Egypt, producing oil from the fractured basement rocks. Due to the complex structural setting of the area and the classical exploration concept that was based mainly on 2D seismic survey data, the area suffered from limited hydrocarbon interest for several years. During this time, most of the drilled wells hit structural highs and resulted in several dry holes. The present study is based on the interpretation of more recently acquired 3D seismic survey data as, matched with the available well logs, used to understand the complex structural setting of the Zeit Bay Field and provide insight into the entrapment style of the implied hydrocarbons. Several selected seismic cross sections were constructed, to extract subsurface geologic information, using available seismic profiles and wells. In addition, structure contour maps (isochronous maps, converted to depth maps) were constructed for the peaks of the basement, Nubian Sandstone, Kareem and Belayim Formations. Folds (anticlines and synclines) and faults (dip-slip) are identified on these maps, both individually and in groups, giving rise to step-like belts, as well as graben and horst blocks.

Subsurface recognition of oolitic facies in carbonate sequence: Exploration and development applications: Ste. Genevieve Formation (Mississippian), Illinois basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bandy, W.F.

1989-08-01

The oolitic grainstone facies of the Ste. Genevieve Limestone is a widespread and highly productive reservoir in the Illinois basin. However, exploration and development of these oolitic facies are hampered by the inability to recognize the reservoir on logs. In many areas, the only log data available are old wireline electric logs. Comparison of cores with log response in northern Lawrence field, Lawrence County, Illinois, indicates a subjective but predictable relationship between log signature and carbonate lithology. Two productive lithologies, dolomite and oolitic grainstone, display well-developed SP curves. However, resistivity response is greatest in dense limestone, less well developed inmore » oolitic grainstone, and poorly developed in dolomites. On gamma-ray logs, oolitic facies can be differentiated from dolomites by their lower radioactivity. Oolitic sands are most easily recognized on porosity logs, where their average porosity is 13.7%, only half the average porosity of dolomites. In a new well, the best information for subsequent offset and development of an oolitic reservoir is provided by porosity and dipmeter logs.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bishop, James K.B.; Wood, Todd

Three Carbon Explorer (CE) floats profiling to kilometer depths in the Southern Ocean tracked dawn-dusk variations of mixing/stratification, particulate organic carbon (POC), and light scattering and sedimentation at 100, 250, and 800 m continuously from January 2002 to April 2003. Data were analyzed in conjunction with contemporaneous satellite winds and chlorophyll and derived subsurface light fields. The CE deployed at 66{sup o}S 172{sup o}W operated in the ice edge zone in absence of light. Two CEs deployed at 55{sup o}S 172{sup o}W recorded wintertime mixing to {approx}400 m, yet observed very different bloom dynamics and sedimentation the following spring. Fourmore » hypotheses are explored. The strongest is that shallow transient stratification of the deep winter mixed layer to shallower than photosynthetic critical depth occurred more frequently in the non-bloom/higher sedimentation case. The lower particle export to 800 m under the bloom was hypothesized to be due to higher interception of sinking carbon by a relatively starved over wintering zooplankton population. In the Southern Ocean surface phytoplankton biomass may counter indicate particle flux at kilometer depths.« less

Validation of Innovative Exploration Technologies for Newberry Volcano: Drill Site Location Map 2010

DOE Data Explorer

Jaffe, Todd

2012-01-01

Newberry seeks to explore "blind" (no surface evidence) convective hydrothermal systems associated with a young silicic pluton on the flanks of Newberry Volcano. This project will employ a combination of innovative and conventional techniques to identify the location of subsurface geothermal fluids associated with the hot pluton. Newberry project drill site location map 2010. Once the exploration mythology is validated, it can be applied throughout the Cascade Range and elsewhere to locate and develop “blind” geothermal resources.

Layering extraction from subsurface radargrams over Greenland and the Martian NPLD by combining wavelet analysis with Hough transforms

NASA Astrophysics Data System (ADS)

Xiong, Si-Ting; Muller, Jan-Peter

2017-04-01

Extracting lines from an imagery is a solved problem in the field of edge detection. Different to images taken by camera, radargrams are a set of radar echo profiles, which record wave energy reflected by subsurface reflectors, at each location of a radar footprint along the satellite's ground track. The radargrams record where there is a dielectric contrast caused by different deposits, and other subsurface features, such as facies, and internal distributions like porosity and fluids. Among the subsurface features, layering is an important one which reflect the sequence of seasonal or yearly deposits on the ground [1-2]. In the field of image processing, line detection methods, such as the Radon Transform or Hough Transform, are able to extract these subsurface layers from rasterised versions of the echograms. However, due to the attenuation of radar waves whilst propagating through geological media, radargrams sometimes suffer from gradient and high background noise. These attributes of radargrams cause errors in detection when conventional line detection methods are directly applied. In this study, we have developed a continuous wavelet analysis technique to be applied directly to the radar echo profiles in a radargram in order to detect segmented lines, and then a conventional line detection method, such as a Hough transform can be applied to connect these segmented lines. This processing chain is tested by using datasets from a radargram acquired by the Multi-channel Coherent Radar Depth Sounder (MCoRDS) on an airborne platform in Greenland and a radargram acquired by the SHAllow RADar (SHARAD) on board the Mars Reconnaissance Orbiter (MRO) [3] over Martian North Polar Layered Deposits (NPLD). Keywords: Subsurface mapping, Radargram, SHARAD, Greenland, Martian NPLD, Subsurface layering, line detection References: [1] Phillips, R. J., et al. "Mars north polar deposits: Stratigraphy, age, and geodynamical response." Science 320.5880 (2008): 1182-1185. [2] Cutts, James A., and Blake H. Lewis. "Models of climate cycles recorded in Martian polar layered deposits." Icarus 50.2 (1982): 216-244. [3] Plaut J J, Picardi G, Safaeinili A, et al. Subsurface radar sounding of the south polar layered deposits of Mars[J]. science, 2007, 316(5821): 92-95. Acknowledgements: Part of the research leading to these results has received funding from the STFC "MSSL Consolidated Grant" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement No. 607379 as well as from the China Scholarship Council and the UCL Dean of MAPS fund.

Exploring Agricultural Drainage's Influence on Wetland and Watershed Connectivity

EPA Science Inventory

Artificial agricultural drainage (i.e. surface ditches or subsurface tile) is an important agricultural management tool. Artificial drainage allows for timely fieldwork and adequate root aeration, resulting in greater crop yields for farmers. This practice is widespread throughou...

Investigating controls on denitrification rates during managed aquifer recharge: Field studies of infiltration

NASA Astrophysics Data System (ADS)

Beganskas, S.; Gorski, G.; Fisher, A. T.; Weir, W. B.; Schmidt, C. M.; Saltikov, C.; Stoneburner, B.; Hernandez, J.; Harmon, R. E.; Weathers, T. S.

2016-12-01

We have designed field experiments to observe and quantify water quality improvement during infiltration in the shallow subsurface, as part of managed aquifer recharge (MAR). We are exploring how microbial diversity and denitrification rate respond to different infiltration rates and the presence or absence of carbon-rich reactive materials (woodchips or biochar). In 2015, we conducted a series of two-week-long field infiltration tests, and in 2016 we are running tests at a new site. For each test, nitrate-rich water (20-25 ppm NO3-N) was continuously applied to 1-m square plots instrumented to measure infiltration rates and sample subsurface water at multiple depths. Soil samples were collected before and after each test to assess microbial diversity. In 2015, we observed infiltration rates of 4-18 m/d, consistent with very sandy soils at our field site. All water samples had >20 ppm DOC, indicating that denitrification was unlikely carbon-limited. There was a net increase in DOC in fluids sampled below woodchips, but no change in DOC in samples from un-amended native soil. Up to 20% of NO3- was removed below woodchips on days with infiltration rates below 15 m/d. Nitrate removal was not observed in native soil, even though infiltration rates were considerably lower, 4 m/d. Isotopic analyses indicate that denitrification is likely the mechanism for nitrate removal. Genomic sequencing of soil microbes shows that microbial populations' relative abundance shifted significantly due to infiltration; further analyses are underway. Our results suggest that rapid infiltration can lead to oxic conditions unfavorable for denitrification, and that a carbon-rich reactive material (woodchips) may stimulate microbially-mediated denitrification. Our experimental design is a novel way to examine factors that impact water quality during infiltration. Nitrate, a pervasive groundwater contaminant, can be removed via denitrification during MAR under some conditions, depending on infiltration rate, available carbon, and substrate material. Our work has applications for designing MAR systems that effectively improve water supply and water quality.

Seismic velocity uncertainties and their effect on geothermal predictions: A case study

NASA Astrophysics Data System (ADS)

Rabbel, Wolfgang; Köhn, Daniel; Bahadur Motra, Hem; Niederau, Jan; Thorwart, Martin; Wuttke, Frank; Descramble Working Group

2017-04-01

Geothermal exploration relies in large parts on geophysical subsurface models derived from seismic reflection profiling. These models are the framework of hydro-geothermal modeling, which further requires estimating thermal and hydraulic parameters to be attributed to the seismic strata. All petrophysical and structural properties involved in this process can be determined only with limited accuracy and thus impose uncertainties onto the resulting model predictions of temperature-depth profiles and hydraulic flow, too. In the present study we analyze sources and effects of uncertainties of the seismic velocity field, which translate directly into depth uncertainties of the hydraulically and thermally relevant horizons. Geological sources of these uncertainties are subsurface heterogeneity and seismic anisotropy, methodical sources are limitations in spread length and physical resolution. We demonstrate these effects using data of the EU-Horizon 2020 project DESCRAMBLE investigating a shallow super-critical geothermal reservoir in the Larderello area. The study is based on 2D- and 3D seismic reflection data and laboratory measurements on representative rock samples under simulated in-situ conditions. The rock samples consistently show P-wave anisotropy values of 10-20% order of magnitude. However, the uncertainty of layer depths induced by anisotropy is likely to be lower depending on the accuracy, with which the spatial orientation of bedding planes can be determined from the seismic reflection images.

Deep Drilling and Sampling via the Wireline Auto-Gopher Driven by Piezoelectric Percussive Actuator and EM Rotary Motor

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart; Zacny, Kris; Paulsen, Gale L; Beegle, Luther; Bao, Xiaoqi

2012-01-01

The ability to penetrate subsurfaces and perform sample acquisition at depths of meters is critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars and Europa. A corer/sampler was developed with the goal of acquiring pristine samples by reaching depths on Mars beyond the oxidized and sterilized zone. To developed rotary-hammering coring drill, called Auto-Gopher, employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor rotates the bit to remove the powdered cuttings. This sampler is a wireline mechanism that is incorporated with an inchworm mechanism allowing thru cyclic coring and core removal to reach great depths. The penetration rate is being optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism that is driven by piezoelectric stack and that was demonstrated to require low axial preload. The Auto-Gopher has been produced taking into account the a lessons learned from the development of the Ultrasonic/Sonic Gopher that was designed as a percussive ice drill and was demonstrated in Antarctica in 2005 to reach about 2 meters deep. A field demonstration of the Auto-Gopher is currently being planned with objective of reaching as deep as 3 to 5 meters in tufa subsurface.

Low-Angle Radar Tracking

DTIC Science & Technology

1976-02-01

Transition from Specular Reflection to Diffuse Scattering. . . 10 Composition of the Electric-Field Vector as Seen at the Radar...r t (16) R • FIGURE P COMPOSITION OF THE ELECTRIC-FIELD VECTOR AS SEEN AT THE RADAR, R, IN FIG. 2. The electric field at the radar, E, is the sum...wavelengths in the VHP and UHF ranges even subsurface characteristics can be important. So in a field experiment one must be careful to measure

Subsurface microscopy of interconnect layers of an integrated circuit.

PubMed

Köklü, F Hakan; Unlü, M Selim

2010-01-15

We apply the NA-increasing lens technique to confocal and wide-field backside microscopy of integrated circuits. We demonstrate 325 nm (lambda(0)/4) lateral spatial resolution while imaging metal structures located inside the interconnect layer of an integrated circuit. Vectorial field calculations are presented justifying our findings.

Transport of tylosin and tylosin-resistance genes in subsurface drainage water from manured fields

USDA-ARS?s Scientific Manuscript database

Animal agriculture appears to contribute to the spread of antibiotic resistance genes, but few studies have quantified gene transport in agricultural fields. The transport of tylosin, tylosin-resistance genes (erm B, F, A) and tylosin-resistant Enterococcus were measured in tile drainage water from ...

After-discovery studies prolong life. [Role of the geologist in oil fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartman, J.A.

1977-05-02

Unless there is a problem, a field may receive little attention by geologists once the primary development phase is over. This is a mistake because analysis of production data may point to areas where more development is needed. In large, multipay fields it is hard to gather the data into a usable form and to attempt to use these data to develop a consistent subsurface interpretation which explains the facts. With wells spaced only a few hundred feet apart, the geologist cannot let his imagination run wild as he can when looking at wildcat country. However, the results obtained frommore » studying oil fields can be very rewarding for both the geologist and his company. For maximum benefit, a subsurface field review should include all facts of the geology, as well as the reservoir, petro-physical, and production engineering aspects. When a field is studied in detail, areas of poor drainage are generally found and those become potential objectives for new wells on recompletions in existing wells. The following are discussed: (1) updip undrained areas; (2) bottom water reservoirs; (3) stringer drainage; and (4) South Pass block 24 field. When a field is studied in detail, unanticipated drainage anomalies are commonly found.« less

A high frequency electromagnetic impedance imaging system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tseng, Hung-Wen; Lee, Ki Ha; Becker, Alex

2003-01-15

Non-invasive, high resolution geophysical mapping of the shallow subsurface is necessary for delineation of buried hazardous wastes, detecting unexploded ordinance, verifying and monitoring of containment or moisture contents, and other environmental applications. Electromagnetic (EM) techniques can be used for this purpose since electrical conductivity and dielectric permittivity are representative of the subsurface media. Measurements in the EM frequency band between 1 and 100 MHz are very important for such applications, because the induction number of many targets is small and the ability to determine the subsurface distribution of both electrical properties is required. Earlier workers were successful in developing systemsmore » for detecting anomalous areas, but quantitative interpretation of the data was difficult. Accurate measurements are necessary, but difficult to achieve for high-resolution imaging of the subsurface. We are developing a broadband non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using an EM impedance approach similar to the MT exploration technique. Electric and magnetic sensors were tested to ensure that stray EM scattering is minimized and the quality of the data collected with the high-frequency impedance (HFI) system is good enough to allow high-resolution, multi-dimensional imaging of hidden targets. Additional efforts are being made to modify and further develop existing sensors and transmitters to improve the imaging capability and data acquisition efficiency.« less

Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

NASA Astrophysics Data System (ADS)

Jackisch, Conrad; Angermann, Lisa; Allroggen, Niklas; Sprenger, Matthias; Blume, Theresa; Tronicke, Jens; Zehe, Erwin

2017-07-01

The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

[Spatial-temporal distribution of bigeye tuna Thunnus obesus in the tropical Atlantic Ocean based on Argo data].

PubMed

Yang, Sheng-long; Jin, Shao-fei; Hua, Cheng-jun; Dai, Yang

2015-02-01

In order to analyze the correlation between spatial-temporal distribution of the bigeye tuna ( Thunnus obesus) and subsurface factors, the study explored the isothermal distribution of subsurface temperatures in the bigeye tuna fishing grounds in the tropical Atlantic Ocean, and built up the spatial overlay chart of the isothermal lines of 9, 12, 13 and 15 °C and monthly CPUE (catch per unit effort) from bigeye tuna long-lines. The results showed that the bigeye tuna mainly distributed in the water layer (150-450 m) below the lower boundary depth of thermocline. At the isothermal line of 12 °C, the bigeye tuna mainly lived in the water layer of 190-260 m, while few individuals were found at water depth more than 400 m. As to the 13 °C isothermal line, high CPUE often appeared at water depth less than 250 m, mainly between 150-230 m, while no CPUE appeared at water depth more than 300 m. The optimum range of subsurface factors calculated by frequency analysis and empirical cumulative distribution function (ECDF) exhibited that the optimum depth range of 12 °C isothermal depth was 190-260 m and the 13 °C isothermal depth was 160-240 m, while the optimum depth difference range of 12 °C isothermal depth was -10 to 100 m and the 13 °C isothermal depth was -40 to 60 m. The study explored the optimum range of subsurface factors (water temperature and depth) that drive horizontal and vertical distribution of bigeye tuna. The preliminary result would help to discover the central fishing ground, instruct fishing depth, and provide theoretical and practical references for the longline production and resource management of bigeye tuna in the Atlantic Ocean.

Exploring the Deep Biosphere in Ophiolite-hosted Systems: What Can Metabolic Processes in Surface Seeps Tell Us About Subsurface Ecosystems in Serpentinizing Fluids?

NASA Astrophysics Data System (ADS)

Meyer-Dombard, D. R.; Cardace, D.; Woycheese, K. M.; Vallalar, B.; Casar, C.; Simon, A.; Arcilla, C. A.

2016-12-01

Serpentinization in the subsurface produces highly reduced, high pH fluids that provide microbial habitats. It is assumed that these deep subsurface fluids contain copious H2 and CH4 gas, little/no inorganic carbon, and limited electron acceptors. As serpentinized fluids reach the oxygenated surface environment, microbial biomes shift and organisms capable of metabolizing O2 thrive (Woycheese et al., 2015). However, the relationship of microbial communities found in surface expressions of serpentinizing fluids to the subsurface biosphere is still a target of exploration. Our work in the Zambales ophiolite (Philippines) defines surface microbial habitats with geochemistry, targeted culturing efforts, and community analysis (Cardace et al., 2015; Woycheese et al., 2015). Springs range from pH 9-11.5, and contain 0.06-2 ppm DO, 0-3.7 ppm sulfide, 30-800 ppm silica. Gases include H2 and CH4 > 10uM, CO2 > 1 mM, and trace amounts of CO. These surface data allow prediction of the subsurface metabolic landscape. For example, Cardace et al., (2015) predicted that metabolism of iron is important in both biospheres. Growth media were designed to target iron reduction yielding heterotrophic and autotrophic iron reducers at high pH. Reduced iron minerals were produced in several cultures (Casar et al., sub.), and isolation efforts are underway. Shotgun metagenomic analysis shows the metabolic capacity for methanogenesis, suggesting microbial origins for some CH4 present. The enzymes methyl coenzyme M reductase, and formylmethanofuran dehydrogenase were detected, and relative abundance increased near the near-anoxic spring source. The metagenomes indicate carbon cycling at these sites is reliant on methanogenesis, acetogenesis, sulfate reduction, and H2 and CH4 oxidation. In this tropical climate, cellulose is also a likely carbon source; cellulose degrading isolates have been obtained. These results indicate a metabolically flexible community at the surface where serpentinizing fluids are expressed. The next step is to understand what these surface systems might tell us about the subsurface biosphere. References: Cardace et al., 2015 Frontiers in Extreme Microbiology 6: doi: 10.3389/fmicb.2015.00010 Woycheese et al., 2015 Frontiers in Extreme Microbiology 6: doi: 10.3389/fmicb.2015.00044

Small County: Development of a Virtual Environment for Instruction in Geological Characterization of Petroleum Reservoirs

NASA Astrophysics Data System (ADS)

Banz, B.; Bohling, G.; Doveton, J.

2008-12-01

Traditional programs of geological education continue to be focused primarily on the evaluation of surface or near-surface geology accessed at outcrops and shallow boreholes. However, most students who graduate to careers in geology work almost entirely on subsurface problems, interpreting drilling records and petrophysical logs from exploration and production wells. Thus, college graduates commonly find themselves ill-prepared when they enter the petroleum industry and require specialized training in drilling and petrophysical log interpretation. To aid in this training process, we are developing an environment for interactive instruction in the geological aspects of petroleum reservoir characterization employing a virtual subsurface closely reflecting the geology of the US mid-continent, in the fictional setting of Small County, Kansas. Stochastic simulation techniques are used to generate the subsurface characteristics, including the overall geological structure, distributions of facies, porosity, and fluid saturations, and petrophysical logs. The student then explores this subsurface by siting exploratory wells and examining drilling and petrophysical log records obtained from those wells. We are developing the application using the Eclipse Rich Client Platform, which allows for the rapid development of a platform-agnostic application while providing an immersive graphical interface. The application provides an array of views to enable relevant data display and student interaction. One such view is an interactive map of the county allowing the student to view the locations of existing well bores and select pertinent data overlays such as a contour map of the elevation of an interesting interval. Additionally, from this view a student may choose the site of a new well. Another view emulates a drilling log, complete with drilling rate plot and iconic representation of examined drill cuttings. From here, students are directed to stipulate subsurface lithology and interval tops as they progress through the drilling operation. Once the interpretation process is complete, the student is guided through an exercise emulating a drill stem test and then is prompted to decide on perforation intervals. The application provides a graphical framework by which the student is guided through well site selection, drilling data interpretation, and well completion or dry-hole abandonment, creating a tight feedback loop by which the student gains an over-arching view of drilling logistics and the subsurface data evaluation process.

Controlling Fluid Flow in the Subsurface through Ureolysis-Controlled Mineral Precipitation

NASA Astrophysics Data System (ADS)

Gerlach, R.; Phillips, A. J.; Cunningham, A. B.; Spangler, L.

2016-12-01

In situ urea hydrolysis has been used by us successfully to manipulate the carbonate alkalinity and control the precipitation of carbonate minerals. Urea hydrolysis can be promoted using microbial cells, enzymes or thermal energy. This technology can be used to mitigate leakage pathways, seal fractures or control fluid transport in the subsurface in hydrocarbon production, enhanced geothermal energy storage, carbon sequestration, nuclear waste disposal, etc. We have completed two field demonstrations of the urea hydrolysis-controlled in situ mineral precipitation technology. The first demonstration showed fracture sealing was possible in a sandstone formation approx. 1120' below ground surface (bgs) and that the fracture had increased resistance to re-fracturing after mineralization treatment. The second field demonstration was performed in a well with an identified channel in the cement near the wellbore at approx. 1020' bgs. The in situ mineralization treatment resulted in reduced pressure decay during shut in periods and reduced injectivity. In addition, a noticeable difference was observed in the solids percentage in the ultrasonic imaging logs before and after biomineralization treatment. The presentation will summarize and put into context the field and our recent laboratory research focusing on permeability manipulation using the in situ ureolysis-driven mineralization technology under ambient and subsurface pressure conditions. We have demonstrated permeability reductions of 3-6 orders of magnitude in 100 µm to 4mm gaps between shale, sandstone and cement/steel interfaces.

Predictability of Subsurface Temperature and the AMOC

NASA Astrophysics Data System (ADS)

Chang, Y.; Schubert, S. D.

2013-12-01

GEOS 5 coupled model is extensively used for experimental decadal climate prediction. Understanding the limits of decadal ocean predictability is critical for making progress in these efforts. Using this model, we study the subsurface temperature initial value predictability, the variability of the Atlantic meridional overturning circulation (AMOC) and its impacts on the global climate. Our approach is to utilize the idealized data assimilation technology developed at the GMAO. The technique 'replay' allows us to assess, for example, the impact of the surface wind stresses and/or precipitation on the ocean in a very well controlled environment. By running the coupled model in replay mode we can in fact constrain the model using any existing reanalysis data set. We replay the model constraining (nudging) it to the MERRA reanalysis in various fields from 1948-2012. The fields, u,v,T,q,ps, are adjusted towards the 6-hourly analyzed fields in atmosphere. The simulated AMOC variability is studied with a 400-year-long segment of replay integration. The 84 cases of 10-year hindcasts are initialized from 4 different replay cycles. Here, the variability and predictability are examined further by a measure to quantify how much the subsurface temperature and AMOC variability has been influenced by atmospheric forcing and by ocean internal variability. The simulated impact of the AMOC on the multi-decadal variability of the SST, sea surface height (SSH) and sea ice extent is also studied.

Sorption of pathogens during sub-surface drip irrigation with wastewater

NASA Astrophysics Data System (ADS)

Levi, Laillach; Gillerman Gillerman, Leonid; Kalavrouziotis, Ioannis; Oron, Gideon

2017-04-01

Water scarcity continues to be one of the major threats to human survival in many regions worldwide, such as Africa, the Mediterranean Basin, the State of California in the US. Due to a mixture of factors such as population growth, reduction in water resources availability and higher demand for high quality waters in these regions these countries face water shortage issues that stem from overuse, extensive extraction of groundwater, and frequent drought events. In addition, there are increases in environmental and health awareness that have led to intensive efforts in the treatment and reuse of nonconventional water sources, mainly wastewater and greywater. One approach to water shortages issues is to use wastewater as means to close the gap between supply and demand. However, the need to treat wastewater and to disinfect it forces additional economic burden on the users, primarily for agricultural irrigation. A possible solution might be to use the soil as a sorbent for the contained pathogens. Under sub-surface drip irrigation, not allowing the wastewater to reach the soil surface, the pathogens will remain in the soil. It was as well shown in field experiments that the opening size of roots will not allow pathogens to penetrate into the plants. Additional advantages such as water saving, protection of the pipe systems and others are also important. Field experiments in commercial fields just emphasize the main advantages of sub-surface drip irrigation.

Subsurface high resolution definition of subsurface heterogeneity for understanding the biodynamics of natural field systems: Advancing the ability for scaling to field conditions. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majer, E.L.; Brockman, F.J.

1998-06-01

'This research is an integrated physical (geophysical and hydrologic) and microbial study using innovative geophysical imaging and microbial characterization methods to identify key scales of physical heterogeneities that affect the biodynamics of natural subsurface environments. Data from controlled laboratory and in-situ experiments at the INEEL Test Area North (TAN) site are being used to determine the dominant physical characteristics (lithologic, structural, and hydrologic) that can be imaged in-situ and correlated with microbial properties. The overall goal of this research is to contribute to the understanding of the interrelationships between transport properties and spatially varying physical, chemical, and microbiological heterogeneity. Themore » outcome will be an improved understanding of the relationship between physical and microbial heterogeneity, thus facilitating the design of bioremediation strategies in similar environments. This report summarizes work as of May 1998, the second year of the project. This work is an extension of basic research on natural heterogeneity first initiated within the DOE/OHER Subsurface Science Program (SSP) and is intended to be one of the building blocks of an integrated and collaborative approach with an INEEL/PNNL effort aimed at understanding the effect of physical heterogeneity on transport properties and biodynamics in natural systems. The work is closely integrated with other EMSP projects at INEEL (Rick Colwell et al.) and PNNL (Fred Brockman and Jim Fredrickson).'« less

Characterizing phosphorus dynamics in tile-drained agricultural fields of eastern Wisconsin

NASA Astrophysics Data System (ADS)

Madison, Allison M.; Ruark, Matthew D.; Stuntebeck, Todd D.; Komiskey, Matthew J.; Good, Lara W.; Drummy, Nancy; Cooley, Eric T.

2014-11-01

Artificial subsurface drainage provides an avenue for the rapid transfer of phosphorus (P) from agricultural fields to surface waters. This is of particular interest in eastern Wisconsin, where there is a concentrated population of dairy farms and high clay content soils prone to macropore development. Through collaboration with private landowners, surface and tile drainage was measured and analyzed for dissolved reactive P (DRP) and total P (TP) losses at four field sites in eastern Wisconsin between 2005 and 2009. These sites, which received frequent manure applications, represent a range of crop management practices which include: two chisel plowed corn fields (CP1, CP2), a no-till corn-soybean field (NT), and a grazed pasture (GP). Subsurface drainage was the dominant pathway of water loss at each site accounting for 66-96% of total water discharge. Average annual flow-weighted (FW) TP concentrations were 0.88, 0.57, 0.21, and 1.32 mg L-1 for sites CP1, CP2, NT, and GP, respectively. Low TP concentrations at the NT site were due to tile drain interception of groundwater flow where large volumes of tile drainage water diluted the FW-TP concentrations. Subsurface pathways contributed between 17% and 41% of the TP loss across sites. On a drainage event basis, total drainage explained between 36% and 72% of the event DRP loads across CP1, CP2, and GP; there was no relationship between event drainflow and event DRP load at the NT site. Manure applications did not consistently increase P concentrations in drainflow, but annual FW-P concentrations were greater in years receiving manure applications compared to years without manure application. Based on these field measures, P losses from tile drainage must be integrated into field level P budgets and P loss calculations on heavily manured soils, while also acknowledging the unique drainage patterns observed in eastern Wisconsin.

Roles of Nano- and Micro-Scale Subsurface Geochemical Reactions on Environmentally Sustainable Geologic Carbon Dioxide Sequestration

NASA Astrophysics Data System (ADS)

Hu, Yandi

Geologic CO2 sequestration (GCS) is a promising approach to reduce anthropogenic CO2 emissions into the atmosphere. At GCS sites, injected CO2 is kept in formation rock by an overlying low permeability caprock. During and after CO2 injection, geochemical reactions can affect the porosity, permeability, and pollutant transport in aquifers. Despite their importance, nano- and micro-scale subsurface geochemical reactions are far from well-understood. Clay mobilization has been reported to decrease aquifer permeability during water flooding, and clay minerals are abundant in caprock. Thus, we studied CO2-brine-clay interactions under varied conditions relevant to different GCS sites (at 35-95°C and under 35-120 atm CO2, in water, NaCl, MgCl2, or CaCl2 solutions). Biotite, Fe-bearing mica, was used as a model clay mineral. We observed numerous fibrous illite precipitates on mica after reaction for only 3 h, which had not been previously reported. A few hours later, the mica surface cracked and fibrous illite detached. The mobilization of fibrous illite can decrease the aquifer's permeability greatly and affect the safety and efficiency of GCS. Mechanisms related to ion exchange, mica swelling, and CO2 intercalation were explored. Oriented aggregation of illite nanoparticles forming the fibrous illite was directly observed, suggesting a new mechanism for fibrous illite formation. Interestingly, besides the pH effect, aqueous CO2 enhances mica cracking over N2. These findings can help to achieve safer subsurface operations. At GCS field sites, Fe concentration increased near the injection sites and originally adsorbed pollutants were released. As the brine flows, Fe re-precipitated because of pH increase. To better predict the fate and transport of aqueous pollutants, the nucleation and growth of Fe(III) (hydr)oxides were studied. New information about sizes and volumes of the Fe(III) (hydr)oxide nanoparticles precipitated in solution and on quartz, mica, and sapphire were provided using small angle X-ray scattering, in the presence of different ions (Al 3+, Cl-, NO3-, and SO 42-). Using complementary techniques, the controlling mechanisms related to surface charge, bond formation, and interfacial energies were explored. These new findings can help better predict pollutant transport in aquifers not only at GCS sites, but also in managed aquifer recharge and acid mine drainage sites.

Mapping Microbial Populations Relative to Sites of Ongoing Serpentinization: Results from the Tablelands Ophiolite Complex, Canada

NASA Astrophysics Data System (ADS)

Schrenk, M. O.; Brazelton, W. J.; Woodruff, Q.; Szponar, N.; Morrill, P. L.

2010-12-01

The aqueous alteration of ultramafic rocks (serpentinization) has been suggested to be a favorable process for the habitability of astrobodies in our solar system including subsurface environments of Mars and Europa. Serpentinization produces copious quantities of hydrogen and small organic molecules, and leads to highly reducing, highly alkaline conditions (up to pH 12) and a lack of dissolved inorganic carbon, which both stimulates and challenges microbial activities. Several environments on Earth provide insight into the relationships between serpentinization and microbial life including slow-spreading mid-ocean ridges, subduction zones, and ophiolite materials emplaced along continental margins. The Tablelands, an ophiolite in western Newfoundland, Canada provides an opportunity to carefully document and map the relationships between geochemical energy, microbial growth, and physiology. Alkaline fluids at the Tablelands originate from 500-million year old oceanic crust and accumulate in shallow pools or seep from beneath serpentinized talus. Fluids, rocks, and gases were collected from the Tablelands during a series of field excursions in 2009 and 2010, and geochemical, microscopic, molecular, and cultivation-based approaches were used to study the serpentinite microbial ecosystem. These samples provide an opportunity to generate a comprehensive map of microbial communities and their activities in space and time. Data indicate that a low but detectable stock of microorganisms inhabit high pH pools associated with end-member serpentinite fluids. Enrichment cultures yielded brightly pigmented colonies related to Alphaproteobacteria, presumably carrying out anoxygenic photosynthesis, and Firmicutes, presumably catalyzing the fermentation of organic matter. Culture-independent analyses of SSU rRNA using T-RFLP indicated low diversity communities of Firmicutes and Archaea in standing alkaline pools, communities of Beta- and Gammaproteobacteria at high pH seeps, and assemblages consisting of diverse taxa at neutral pH background sites. Terrestrial serpentinite-hosted microbial ecosystems with their accessibility, their low phylogenetic diversity, and limited range of energetic resources provide an excellent opportunity to explore the interplay between geochemical energy and life and to elucidate the native serpentinite subsurface biosphere. From the perspective of Mars exploration, studies of serpentinite ecosystems provide the opportunity to pinpoint the organisms and physiological adaptations specifically associated with serpentinization and to directly measure their geochemical impacts. Both of these results will inform modeling and life detection efforts of the Martian subsurface environment.

Implementation of gINT software at the Virginia Department of Transportation.

DOT National Transportation Integrated Search

2008-01-01

A set of software tools was developed to enable staff of the Virginia Department of Transportation (VDOT) and consultants to streamline processing of subsurface exploration data. Built around the gINT program (geotechnical database and graphics packa...

Investigation of North Pond crustal fluids by poised potential methods

NASA Astrophysics Data System (ADS)

Jones, R. M.; Orcutt, B.

2017-12-01

Microbes are present in the deep subsurface but their rates of activity, potential metabolisms and roles in the environment are still largely unknown. The marine deep crustal subsurface accounts for approximately 2.3x1018 m2 of the earth's volume, making this environment potentially significant to earth processes despite low productivity inherent in resource limited conditions. This has implications for geochemical cycling and exploring limits of life, linking to the `follow the energy' approach for defining habitability on earth and further afield. Most resources for life in the marine deep crust originate from rock. One subset of lithotrophic interactions involves direct transfer between electron acceptors and donors embedded in minerals and microbes. In this investigation, poised potential methods such as chronoamperometry were used to investigate mineral-microbe electron transfer interactions in the context of North Pond, a Mid-Atlantic ridge site representative of cool, sediment-covered basalts that make up the majority of the deep marine subsurface. Electrodes were poised at potentials corresponding approximately to particular lithotrophic oxidation reactions to enrich for sub-sections of North Pond deep subsurface fluid communities that were associated with direct electron transfer at these potentials.

[Search for life in deep biospheres].

PubMed

Naganuma, Takeshi

2003-12-01

The life in deep biospheres bridges conventional biology and future exobiology. This review focuses the microbiological studies from the selected deep biospheres, i.e., deep-sea hydrothermal vents, sub-hydrothermal vents, terrestrial subsurface and a sub-glacier lake. The dark biospheres facilitate the emergence of organisms and communities dependent on chemolithoautotrophy, which are overwhelmed by photoautotrophy (photosynthesis) in the surface biospheres. The life at deep-sea hydrothermal vents owes much to chemolithoautotrophy based on the oxidation of sulfide emitted from the vents. It is likely that similarly active bodies such as the Jovian satellite Europa may have hydrothermal vents and associated biological communities. Anoxic or anaerobic condition is characteristic of deep subsurface biospheres. Subsurface microorganisms exploit available oxidants, or terminal electron acceptors (TEA), for anaerobic respiration. Sulfate, nitrate, iron (III) and CO2 are the representative TEAs in the deep subsurface. Below the 3000-4000 m-thick glacier on Antarctica, there have been >70 lakes with liquid water located. One of such sub-glacial lakes, Lake Vostok, is about to be drill-penetrated for microbiological studies. These deep biosphere "platforms" provide new knowledge about the diversity and potential of the Earth's life. The expertise obtained from the deep biosphere expeditions will facilitate the capability of exobiologial exploration.

Potential Elevation Biases for Laser Altimeters from Subsurface Scattered Photons: Laboratory and Model Exploration of Green Light Scattering in Snow

NASA Astrophysics Data System (ADS)

Greeley, A.; Neumann, T.; Markus, T.; Kurtz, N. T.; Cook, W. B.

2015-12-01

Existing visible light laser altimeters such as MABEL (Multiple Altimeter Beam Experimental Lidar) - a single photon counting simulator for ATLAS (Advanced Topographic Laser Altimeter System) on NASA's upcoming ICESat-2 mission - and ATM (Airborne Topographic Mapper) on NASA's Operation IceBridge mission provide scientists a view of Earth's ice sheets, glaciers, and sea ice with unprecedented detail. Precise calibration of these instruments is needed to understand rapidly changing parameters like sea ice freeboard and to measure optical properties of surfaces like snow covered ice sheets using subsurface scattered photons. Photons travelling into snow, ice, or water before scattering back to the altimeter receiving system (subsurface photons) travel farther and longer than photons scattering off the surface only, causing a bias in the measured elevation. We seek to identify subsurface photons in a laboratory setting using a flight-tested laser altimeter (MABEL) and to quantify their effect on surface elevation estimates for laser altimeter systems. We also compare these estimates with previous laboratory measurements of green laser light transmission through snow, as well as Monte Carlo simulations of backscattered photons from snow.

Satellite tidal magnetic signals constrain oceanic lithosphere-asthenosphere boundary.

PubMed

Grayver, Alexander V; Schnepf, Neesha R; Kuvshinov, Alexey V; Sabaka, Terence J; Manoj, Chandrasekharan; Olsen, Nils

2016-09-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. We use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals a ≈72-km-thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

Silica-coated titania and zirconia colloids for subsurface transport field experiments

USGS Publications Warehouse

Ryan, Joseph N.; Elimelech, Menachem; Baeseman, Jenny L.; Magelky, Robin D.

2000-01-01

Silica-coated titania (TiO2) and zirconia (ZrO2) colloids were synthesized in two sizes to provide easily traced mineral colloids for subsurface transport experiments. Electrophoretic mobility measurements showed that coating with silica imparted surface properties similar to pure silica to the titania and zirconia colloids. Measurements of steady electrophoretic mobility and size (by dynamic light scattering) over a 90-day period showed that the silica-coated colloids were stable to aggregation and loss of coating. A natural gradient field experiment conducted in an iron oxide-coated sand and gravel aquifer also showed that the surface properties of the silica-coated colloids were similar. Colloid transport was traced at μg L-1 concentrations by inductively coupled plasma-atomic emission spectroscopy measurement of Ti and Zr in acidified samples.

Mud Volcanoes - A New Class of Sites for Geological and Astrobiological Exploration of Mars

NASA Technical Reports Server (NTRS)

Allen, C.C.; Oehler, D.Z.; Baker, D.M.

2009-01-01

Mud volcanoes provide a unique low-temperature window into the Earth s subsurface - including the deep biosphere - and may prove to be significant sources of atmospheric methane. The identification of analogous features on Mars would provide an important new class of sites for geological and astrobiological exploration. We report new work suggesting that features in Acidalia Planitia are most consistent with their being mud volcanoes.

Ecohydrology of Deep Fractured Rocks at Homestake DUSEL

NASA Astrophysics Data System (ADS)

Kieft, T. L.; Boutt, D. F.; Murdoch, L. C.; Wang, H. F.

2009-12-01

The Deep Underground Science and Engineering Laboratory (DUSEL) at Homestake in SD will provide an unprecedented opportunity to study the terrestrial subsurface. Such a study could fundamentally change the way we view the origin and early evolution of life on Earth, the search for novel materials, and the generation of energy. Knowledge of subsurface life has come from only a few boreholes and deep mines. DUSEL will enable the first detailed study of a deep ecosystem in the context of the hydrology, geochemistry, and rock system state that sustain it. We are guided by the over-arching question: What controls the distribution and evolution of subsurface life? Our hypothesis is that these controls are dominated by processes related to geology, geochemistry, geomechanics, and hydrology. Themes of scaling and the development of facies, or zones of similar characteristics cut across all the processes. The ecohydrologic setting of DUSEL Homestake is characterized by a vast expanse of fractured metamorphic rock cut by 100s of km of tunnels and boreholes. Many km3 of the region have been highly affected by mining activities; adjacent regions are partially desaturated; and more distal regions are pristine and presumed to harbor indigenous microbial ecosystems. Simulations along with descriptions of the mine suggest division into zones, or ecohydrologic facies, where essential characteristics related to the requirements for life are expected to be similar. These ecohydrologic facies are a primary organizing principle for our investigation. The Deep EcoHydrology Experiment will consist of field studies supported by numerical simulations. The experimental activities include a particularly exciting opportunity to probe the lower limits of the biosphere using deep drilling technology deployed from the lowest reaches of the facility (2440 m below the surface). The use of the flooding/dewatering event as a tracer combined with hydrologic and mechanical stressors form a theme that cuts across many of the experimental activities. Five key experimental activities have been identified that will enable motivating hypotheses to be tested: 1) Initial Characterization, 2) Flow System, 3) Stress and Deformation, 4) Exploration, and 5) Cross-cutting activities. The International Continental Drilling Program has approved a preproposal for an ICDP ecohydrology project at DUSEL. The development of a long-term deep geosciences observatory at the Homestake DUSEL will revolutionize the field of deep sub-surface ecohydrology. The opportunities for young scientists and international participation in such a facility will be tremendous. Results from the work will have wide ranging implications as 20% of the current earth’s surface consists of a similar geologic setting. DUSEL will also facilitate experiential learning for K-12 through graduate school students working alongside world-class geoscientists.

Gypsies in the palace: Experimentalist's view on the use of 3-D physics-based simulation of hillslope hydrological response

USGS Publications Warehouse

James, A.L.; McDonnell, Jeffery J.; Tromp-Van Meerveld, I.; Peters, N.E.

2010-01-01

As a fundamental unit of the landscape, hillslopes are studied for their retention and release of water and nutrients across a wide range of ecosystems. The understanding of these near-surface processes is relevant to issues of runoff generation, groundwater-surface water interactions, catchment export of nutrients, dissolved organic carbon, contaminants (e.g. mercury) and ultimately surface water health. We develop a 3-D physics-based representation of the Panola Mountain Research Watershed experimental hillslope using the TOUGH2 sub-surface flow and transport simulator. A recent investigation of sub-surface flow within this experimental hillslope has generated important knowledge of threshold rainfall-runoff response and its relation to patterns of transient water table development. This work has identified components of the 3-D sub-surface, such as bedrock topography, that contribute to changing connectivity in saturated zones and the generation of sub-surface stormflow. Here, we test the ability of a 3-D hillslope model (both calibrated and uncalibrated) to simulate forested hillslope rainfall-runoff response and internal transient sub-surface stormflow dynamics. We also provide a transparent illustration of physics-based model development, issues of parameterization, examples of model rejection and usefulness of data types (e.g. runoff, mean soil moisture and transient water table depth) to the model enterprise. Our simulations show the inability of an uncalibrated model based on laboratory and field characterization of soil properties and topography to successfully simulate the integrated hydrological response or the distributed water table within the soil profile. Although not an uncommon result, the failure of the field-based characterized model to represent system behaviour is an important challenge that continues to vex scientists at many scales. We focus our attention particularly on examining the influence of bedrock permeability, soil anisotropy and drainable porosity on the development of patterns of transient groundwater and sub-surface flow. Internal dynamics of transient water table development prove to be essential in determining appropriate model parameterization. ?? 2010 John Wiley & Sons, Ltd.

Modeling and analysis of CSAMT field source effect and its characteristics

NASA Astrophysics Data System (ADS)

Da, Lei; Xiaoping, Wu; Qingyun, Di; Gang, Wang; Xiangrong, Lv; Ruo, Wang; Jun, Yang; Mingxin, Yue

2016-02-01

Controlled-source audio-frequency magnetotellurics (CSAMT) has been a highly successful geophysical tool used in a variety of geological exploration studies for many years. However, due to the artificial source used in the CSAMT technique, two important factors are considered during interpretation: non-plane-wave or geometric effects and source overprint effects. Hence, in this paper we simulate the source overprint effects and analyzed the rule and characteristics of its influence on CSAMT applications. Two-dimensional modeling was carried out using an adaptive unstructured finite element method to simulate several typical models. Also, we summarized the characteristics and rule of the source overprint effects and analyzed its influence on the data taken over several mining areas. The results obtained from the study shows that the occurrence and strength of the source overprint effect is dependent on the location of the source dipole, in relation to the receiver and the subsurface geology. In order to avoid source overprint effects, three principle were suggested to determine the best location for the grounded dipole source in the field.

Exploring Microbial Life in Oxic Sediments Underlying Oligotrophic Ocean Gyres

NASA Astrophysics Data System (ADS)

Ziebis, W.; Orcutt, B.; Wankel, S. D.; D'Hondt, S.; Szubin, R.; Kim, J. N.; Zengler, K.

2015-12-01

Oxygen, carbon and nutrient availability are defining parameters for microbial life. In contrast to organic-rich sediments of the continental margins, where high respiration rates lead to a depletion of O2 within a thin layer at the sediment surface, it was discovered that O2 penetrates several tens of meters into organic-poor sediments underlying oligotrophic ocean gyres. In addition, nitrate, another important oxidant, which usually disappears rapidly with depth in anoxic sediments, tends to accumulate above seawater concentrations in the oxic subsurface, reflecting the importance of nitrogen cycling processes, including both nitrification and denitrification. Two IODP drilling expeditions were vital for exploring the nature of the deep subsurface beneath oligotrophic ocean gyres, expedition 329 to the South Pacific Gyre (SPG) and expedition 336 to North Pond, located on the western flank of the Mid-Atlantic ridge beneath the North Atlantic Gyre. Within the ultra-oligotrophic SPG O2 penetrates the entire sediment column from the sediment-water interface to the underlying basement to depths of > 75 m. At North Pond, a topographic depression filled with sediment and surrounded by steep basaltic outcrops, O2 penetrates deeply into the sediment (~ 30 m) until it eventually becomes depleted. O2 also diffuses upward into the sediment from seawater circulating within the young crust underlying the sediment, resulting in a deep oxic layer several meters above the basalt. Despite low organic carbon contents microbial cells persist throughout the entire sediment column within the SPG (> 75 m) and at North Pond, albeit at low abundances. We explored the nature of the subsurface microbial communities by extracting intact cells from large volumes of sediment obtained from drill cores of the two expeditions. By using CARD-FiSH, amplicon (16s rRNA) and metagenome sequencing we shed light on the phylogenetic and functional diversity of the elusive communities residing in the deep oxic sediments of these two different areas. Given the global extent of this oxic subsurface studies of the diversity and metabolic potential of its biome, together with the analyses of porewater geochemical and isotopic composition, are beginning to reveal its role in global biogeochemical cycles.

Unprecedented Zipangu Underworld of the Moon Exploration (UZUME)

NASA Astrophysics Data System (ADS)

Haruyama, J.; Kawano, I.; Kubota, T.; Otsuki, M.; Kato, H.; Nishibori, T.; Iwata, T.; Yamamoto, Y.; Nagamatsu, A.; Shimada, K.; Ishihara, Y.; Hasenaka, T.; Morota, T.; Nishino, M. N.; Hashizume, K.; Saiki, K.; Shirao, M.; Komatsu, G.; Hasebe, N.; Shimizu, H.; Miyamoto, H.; Kobayashi, K.; Yokobori, S.; Michikami, T.; Yamamoto, S.; Yokota, Y.; Arisumi, H.; Ishigami, G.; Furutani, K.; Michikawa, Y.

2014-04-01

On the Moon, three huge vertical holes (several tens to a hundred meters in diameter and depth) were discovered in SELENE (nicknamed Kaguya) Terrain Camera data of 10 m pixel resolution. These holes are probably skylights of underground large caverns such as lava tubes, or magma chambers. The huge holes and their associated subsurface caverns are among the most important future exploration targets from the viewpoint of constructing lunar bases and many scientific aspects. We are now planning to explore the caverns through the skylight holes. We name the project as UZUME (Unprecedented Zipangu (Japan) Underworld of the Moon Exploration).

2016 Summer Series - Penelope Boston - Subsurface Astrobiology: Cave Habitats on Earth, Mars and Beyond

NASA Image and Video Library

2016-08-09

In our quest to explore other planets, we only have our own planet as an analogue to the environments we may find life. By exploring extreme environments on Earth, we can model conditions that may be present on other celestial bodies and select locations to explore for signatures of life. Dr. Penelope Boston, the new director of the NASA Astrobiology Institute at Ames, will describe her work in some of Earth’s most diverse caves and how they inform future exploration of Mars and the search for life in our solar system.

Radio Sounding Science at High Powers

NASA Technical Reports Server (NTRS)

Green, J. L.; Reinisch, B. W.; Song, P.; Fung, S. F.; Benson, R. F.; Taylor, W. W. L.; Cooper, J. F.; Garcia, L.; Markus, T.; Gallagher, D. L.

2004-01-01

Future space missions like the Jupiter Icy Moons Orbiter (JIMO) planned to orbit Callisto, Ganymede, and Europa can fully utilize a variable power radio sounder instrument. Radio sounding at 1 kHz to 10 MHz at medium power levels (10 W to kW) will provide long-range magnetospheric sounding (several Jovian radii) like those first pioneered by the radio plasma imager instrument on IMAGE at low power (less than l0 W) and much shorter distances (less than 5 R(sub E)). A radio sounder orbiting a Jovian icy moon would be able to globally measure time-variable electron densities in the moon ionosphere and the local magnetospheric environment. Near-spacecraft resonance and guided echoes respectively allow measurements of local field magnitude and local field line geometry, perturbed both by direct magnetospheric interactions and by induced components from subsurface oceans. JIMO would allow radio sounding transmissions at much higher powers (approx. 10 kW) making subsurface sounding of the Jovian icy moons possible at frequencies above the ionosphere peak plasma frequency. Subsurface variations in dielectric properties, can be probed for detection of dense and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts.

A novel and generalized approach in the inversion of geoelectrical resistivity data using Artificial Neural Networks (ANN)

NASA Astrophysics Data System (ADS)

Raj, A. Stanley; Srinivas, Y.; Oliver, D. Hudson; Muthuraj, D.

2014-03-01

The non-linear apparent resistivity problem in the subsurface study of the earth takes into account the model parameters in terms of resistivity and thickness of individual subsurface layers using the trained synthetic data by means of Artificial Neural Networks (ANN). Here we used a single layer feed-forward neural network with fast back propagation learning algorithm. So on proper training of back propagation networks it tends to give the resistivity and thickness of the subsurface layer model of the field resistivity data with reference to the synthetic data trained in the appropriate network. During training, the weights and biases of the network are iteratively adjusted to make network performance function level more efficient. On adequate training, errors are minimized and the best result is obtained using the artificial neural networks. The network is trained with more number of VES data and this trained network is demonstrated by the field data. The accuracy of inversion depends upon the number of data trained. In this novel and specially designed algorithm, the interpretation of the vertical electrical sounding has been done successfully with the more accurate layer model.

Statistics of chemical gradients in heterogeneous porous media

NASA Astrophysics Data System (ADS)

Le Borgne, T.; Huck, P. D.; Dentz, M.; Villermaux, E.

2017-12-01

As they create chemical disequilibrium and drive mixing fluxes, spatial gradients in solute concentrations exert a strong control on mixing and biogeochemical reactions in the subsurface. Large concentration gradients may develop in particular at interfaces between surface water and groundwater bodies, such as hyporheic zones, sea water - surface water interfaces or recharge areas. They also develop around contaminant plumes and fluids injected in subsurface operations. While macrodispersion theories predict smooth gradients, decaying in time due to dispersive dissipation, we show that concentration gradients are sustained by flow heterogeneity and have broadly distributed values. We present a general theory predicting the statistics of concentration gradients from the flow heterogeneity (Le Borgne et al., 2017). Analytical predictions are validated from high resolution simulations of transport in heterogeneous Darcy fields ranging from low to high permeability variances and low to high Peclet numbers. This modelling framework hence opens new perspectives for quantifying the dynamics of chemical gradients and the kinetics of associated biogeochemical reactions in heterogeneous subsurface environments.Reference:Le Borgne T., P.D. Huck, M. Dentz and E. Villermaux (2017) Scalar gradients in stirred mixtures and the deconstruction of random fields, J. of Fluid Mech. vol. 812, pp. 578-610 doi:10.1017/jfm.2016.799

Abnormal pressures as hydrodynamic phenomena

USGS Publications Warehouse

Neuzil, C.E.

1995-01-01

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Design and Evaluation of a Fiber Optic Probe as a means of Subsurface Planetary Exploration

NASA Astrophysics Data System (ADS)

Pilgrim, Robert Paul

The Optical Probe for Regolith Analysis (OPRA) is an instrumentation concept designed to provide spectroscopic analysis of the near subsurface of unconsolidated regolith on bodies such as moons, asteroids and planets. Below a chemically altered surface may lay the geological history in the form of stratigraphy that is shielded from degradation due to harsh external environments. Most of what we know about our solar system comes from remote platforms, such as satellites that are deployed into orbit around the target body. In the case of Mars, we have had several successful landers and rovers however, with the exception of the Mars Science Laboratory that just drilled its first hole, the complexity of subsurface excavation has limited the extent of subsurface exploration to simple scoops deployed on the ends of robotic arms which, by their very nature, will erase any stratigraphy that it may be digging into. The OPRA instrumentation concept allows for an integrated, lightweight and simple apparatus for subsurface exploration via a small, spike like structure which contains integrated optical fibers coupled to small windows running down the length of the probe. Each window is connected to a spectrometer housed onboard the deploying spacecraft. Each window is separately interrogated via the spectrometer over the wavelength range 1-2.5 nm to produce a spectroscopic profile as a function of depth. This project takes the Technology Readiness Level (TRL) of the OPRA instrumentation concept to level 3, which is defined by NASA to be the demonstration either analytically or experimentally of the proof of concept for critical functions of the proposed instrument. Firstly, to demonstrate that optical fibers are feasible for this type of application, we report on the techniques used by NASA to space qualify optical fibers. We investigate the optical performance of several fiber optic bundle configurations, both experimentally and numerically, to help optimize bundle performance. Optical bundles were then spectrally validated via a series of spectral comparisons between standardized reflectance spectroscopy targets and spectra obtained with the bundles. We also report on the integration of fiber optical bundles into other research and experimental results from several other groups within our research teams to obtain spectra under a more "space like" environment. Finally, the probe housing structural performance was investigated via finite element analysis, using probe penetration forces derived from data analysis of experimentation conducted by the Apollo lunar missions, and investigations into a mechanical analogue for the Martian regolith.

A Mobile Acoustic Subsurface Sensing (MASS) System for Rapid Roadway Assessment

PubMed Central

Lu, Yifeng; Zhang, Yi; Cao, Yinghong; McDaniel, J. Gregory; Wang, Ming L.

2013-01-01

Surface waves are commonly used for vibration-based nondestructive testing for infrastructure. Spectral Analysis of Surface Waves (SASW) has been used to detect subsurface properties for geologic inspections. Recently, efforts were made to scale down these subsurface detection approaches to see how they perform on small-scale structures such as concrete slabs and pavements. Additional efforts have been made to replace the traditional surface-mounted transducers with non-contact acoustic transducers. Though some success has been achieved, most of these new approaches are inefficient because they require point-to-point measurements or off-line signal analysis. This article introduces a Mobile Acoustic Subsurface Sensing system as MASS, which is an improved surface wave based implementation for measuring the subsurface profile of roadways. The compact MASS system is a 3-wheeled cart outfitted with an electromagnetic impact source, distance register, non-contact acoustic sensors and data acquisition/processing equipment. The key advantage of the MASS system is the capability to collect measurements continuously at walking speed in an automatic way. The fast scan and real-time analysis advantages are based upon the non-contact acoustic sensing and fast air-coupled surface wave analysis program. This integration of hardware and software makes the MASS system an efficient mobile prototype for the field test. PMID:23698266

Microbial redox processes in deep subsurface environments and the potential application of (per)chlorate in oil reservoirs

PubMed Central

Liebensteiner, Martin G.; Tsesmetzis, Nicolas; Stams, Alfons J. M.; Lomans, Bartholomeus P.

2014-01-01

The ability of microorganisms to thrive under oxygen-free conditions in subsurface environments relies on the enzymatic reduction of oxidized elements, such as sulfate, ferric iron, or CO2, coupled to the oxidation of inorganic or organic compounds. A broad phylogenetic and functional diversity of microorganisms from subsurface environments has been described using isolation-based and advanced molecular ecological techniques. The physiological groups reviewed here comprise iron-, manganese-, and nitrate-reducing microorganisms. In the context of recent findings also the potential of chlorate and perchlorate [jointly termed (per)chlorate] reduction in oil reservoirs will be discussed. Special attention is given to elevated temperatures that are predominant in the deep subsurface. Microbial reduction of (per)chlorate is a thermodynamically favorable redox process, also at high temperature. However, knowledge about (per)chlorate reduction at elevated temperatures is still scarce and restricted to members of the Firmicutes and the archaeon Archaeoglobus fulgidus. By analyzing the diversity and phylogenetic distribution of functional genes in (meta)genome databases and combining this knowledge with extrapolations to earlier-made physiological observations we speculate on the potential of (per)chlorate reduction in the subsurface and more precisely oil fields. In addition, the application of (per)chlorate for bioremediation, souring control, and microbial enhanced oil recovery are addressed. PMID:25225493

Indications of Subsurface Ice: Polygons on the Northern Plains

NASA Technical Reports Server (NTRS)

1999-01-01

Someone's kitchen floor? A stone patio?This picture actually does show a floor--the floor of an old impact crater on the northern plains of Mars. Each 'tile' is somewhat larger than a football field. Polygonal patterns are familiar to Mars geologists because they are also common in arctic and antarctic environments on Earth. Typically, such polygons result from the stresses induced in frozen ground by the freeze-thaw cycles of subsurface ice. This picture was taken by MOC in May 1999 and is illuminated from the lower left.

Three-phase heaters with common overburden sections for heating subsurface formations

DOEpatents

Vinegar, Harold J [Bellaire, TX

2012-02-14

A heating system for a subsurface formation is described. The heating system includes three substantially u-shaped heaters with first end portions of the heaters being electrically coupled to a single, three-phase wye transformer and second end portions of the heaters being electrically coupled to each other and/or to ground. The three heaters may enter the formation through a first common wellbore and exit the formation through a second common wellbore so that the magnetic fields of the three heaters at least partially cancel out in the common wellbores.

Shallow subsurface drip irrigation (S3DI) for small irregular-shaped fields in the southeast

USDA-ARS?s Scientific Manuscript database

Field tests were conducted using S3DI on cotton (Gossypium hirsutum, L.), corn (Zea mays, L.), and peanut (Arachis hypogeae, L.) rotations to investigate yield potential and economic sustainability of this irrigation system. Drip tubing was installed in alternate row middles, strip tillage was used ...

Exploration of the Moon with Remote Sensing, Ground-Penetrating Radar, and the Regolith-Evolved Gas Analyzer (REGA)

NASA Technical Reports Server (NTRS)

Cooper, B. L.; Hoffman, J. H.; Allen, Carlton C.; McKay, David S.

1998-01-01

There are two important reasons to explore the Moon. First, we would like to know more about the Moon itself: its history, its geology, its chemistry, and its diversity. Second, we would like to apply this knowledge to a useful purpose. namely finding and using lunar resources. As a result of the recent Clementine and Lunar Prospector missions, we now have global data on the regional surface mineralogy of the Moon, and we have good reason to believe that water exists in the lunar polar regions. However, there is still very little information about the subsurface. If we wish to go to the lunar polar regions to extract water, or if we wish to go anywhere else on the Moon and extract (or learn) anything at all, we need information in three dimensions an understanding of what lies below the surface, both shallow and deep. The terrestrial mining industry provides an example of the logical steps that lead to an understanding of where resources are located and their economic significance. Surface maps are examined to determine likely locations for detailed study. Geochemical soil sample surveys, using broad or narrow grid patterns, are then used to gather additional data. Next, a detailed surface map is developed for a selected area, along with an interpretation of the subsurface structure that would give rise to the observed features. After that, further sampling and geophysical exploration are used to validate and refine the original interpretation, as well as to make further exploration/ mining decisions. Integrating remotely sensed, geophysical, and sample datasets gives the maximum likelihood of a correct interpretation of the subsurface geology and surface morphology. Apollo-era geophysical and automated sampling experiments sought to look beyond the upper few microns of the lunar surface. These experiments, including ground-penetrating radar and spectrometry, proved the usefulness of these methods for determining the best sites for lunar bases and lunar mining operations.

Complex oolite reservoirs in Ste. Genevieve limestone (Mississippian) at Folsomville field, Warrick County, Indiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuppann, C.W.

1989-09-01

Correlation of productive zones at the Folsomville field is difficult because lithology in the upper part of the Ste. Genevieve Limestone, which contains oolite bodies, is both laterally and vertically variable. The problem is further complicated by significant thickness variations of this interval that result in juxtaposed positions of porosity zones when geophysical logs are correlated side by side. Subsurface slice mapping, now an infrequently used method of subsurface analysis, can resolve complex geometries of oolite bodies and account for seemingly incongruous patterns of hydrocarbon production. Any mappable parameter can be envisioned in three dimensions by using the slice-map method.more » Net porosity and lithofacies slice maps, constructed at 2-ft intervals beneath a persistent stratigraphic marker near the top of the Ste. Genevieve Limestone, describe the stratigraphic geometries of oolite reservoirs at the Folsomville field. Integrating fluid content and well-production histories with the slice maps allows patterns of hydrocarbon production to be deciphered, a procedure that should provide a valuable guide in designing the most effect enhanced recovery program for the field.« less

Subsurface Structure of the Ismenius Area and Implications for Evolution of the Martian Dichotomy and Magnetic Field

NASA Technical Reports Server (NTRS)

Smrekar, S. E.; Raymond, C. A.; McGill, G. E.

2004-01-01

The Martian dichotomy divides the smooth, northern lowlands from the rougher southern highlands. The northern lowlands are largely free of magnetic anomalies, while the majority of the significant magnetic anomalies are located in the southern highlands. An elevation change of 2-4 km is typical across the dichotomy, and is up to 6 km locally. We examine a part of the dichotomy that is likely to preserve the early history of the dichotomy as it is relatively unaffected by major impacts and erosion. This study contains three parts: 1) the geologic history, which is summarized below and detailed in McGill et al., 2) the study of the gravity and magnetic field to better constrain the subsurface structure and history of the magnetic field (this abstract), and 3) modeling of the relaxation of this area. Our overall goal is to place constraints on formation models of the dichotomy by constraining lithospheric properties. Initial results for the analysis of the geology, gravity, and magnetic field studies are synthesized in Smrekar et al..

Influence of spatial and temporal variability of subsurface soil moisture and temperature on vapour intrusion

NASA Astrophysics Data System (ADS)

Bekele, Dawit N.; Naidu, Ravi; Chadalavada, Sreenivasulu

2014-05-01

A comprehensive field study was conducted at a site contaminated with chlorinated solvents, mainly trichloroethylene (TCE), to investigate the influence of subsurface soil moisture and temperature on vapour intrusion (VI) into built structures. Existing approaches to predict the risk of VI intrusion into buildings assume homogeneous or discrete layers in the vadose zone through which TCE migrates from an underlying source zone. In reality, the subsurface of the majority of contaminated sites will be subject to significant variations in moisture and temperature. Detailed site-specific data were measured contemporaneously to evaluate the impact of spatial and temporal variability of subsurface soil properties on VI exposure assessment. The results revealed that indoor air vapour concentrations would be affected by spatial and temporal variability of subsurface soil moisture and temperature. The monthly monitoring of soil-gas concentrations over a period of one year at a depth of 3 m across the study site demonstrated significant variation in TCE vapour concentrations, which ranged from 480 to 629,308 μg/m3. Soil-gas wells at 1 m depth exhibited high seasonal variability in TCE vapour concentrations with a coefficient of variation 1.02 in comparison with values of 0.88 and 0.74 in 2 m and 3 m wells, respectively. Contour plots of the soil-gas TCE plume during wet and dry seasons showed that the plume moved across the site, hence locations of soil-gas monitoring wells for human risk assessment is a site specific decision. Subsurface soil-gas vapour plume characterisation at the study site demonstrates that assessment for VI is greatly influenced by subsurface soil properties such as temperature and moisture that fluctuate with the seasons of the year.

Residues of endosulfan in surface and subsurface agricultural soil and its bioremediation.

PubMed

Odukkathil, Greeshma; Vasudevan, Namasivayam

2016-01-01

The persistence of many hydrophobic pesticides has been reported by various workers in various soil environments and its bioremediation is a major concern due to less bioavailability. In the present study, the pesticide residues in the surface and subsurface soil in an area of intense agricultural activity in Pakkam Village of Thiruvallur District, Tamilnadu, India, and its bioremediation using a novel bacterial consortium was investigated. Surface (0-15 cm) and subsurface soils (15-30 cm and 30-40 cm) were sampled, and pesticides in different layers of the soil were analyzed. Alpha endosulfan and beta endosulfan concentrations ranged from 1.42 to 3.4 mg/g and 1.28-3.1 mg/g in the surface soil, 0.6-1.4 mg/g and 0.3-0.6 mg/g in the subsurface soil (15-30 cm), and 0.9-1.5 mg/g and 0.34-1.3 mg/g in the subsurface soil (30-40 cm) respectively. Residues of other persistent pesticides were also detected in minor concentrations. These soil layers were subjected to bioremediation using a novel bacterial consortium under a simulated soil profile condition in a soil reactor. The complete removal of alpha and beta endosulfan was observed over 25 days. Residues of endosulfate were also detected during bioremediation, which was subsequently degraded on the 30th day. This study revealed the existence of endosulfan in the surface and subsurface soils and also proved that the removal of such a ubiquitous pesticide in the surface and subsurface environment can be achieved in the field by bioaugumenting a biosurfactant-producing bacterial consortium that degrades pesticides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Understanding Subsurface Geoelectrical and Structural Constrains for Low Frequency Radar Sounding of Jovian Satellites

NASA Astrophysics Data System (ADS)

Heggy, Essam; Bruzzone, Lorenzo; Beck, Pierre; Doute, Sylvain; Gim, Youngyu; Herique, Alain; Kofman, Wlodek; Orosei, Roberto; Plaut, Jeffery; Rosen, Paul; Seu, Roberto

2010-05-01

Thermally stable Ice sheets on earth are known to be among the most favorable geophysical contexts for deep subsurface sounding radars. Penetrations ranging from few to several hundreds of meters have been observed at 10 to 60 MHz when sounding homogenous and pure ice sheets in Antarctica and in Alaskan glaciers. Unlike the terrestrial case, ice sheets on Jovian satellites are older formations with a more complex matrix of mineral inclusions with an even three dimensional distribution on the surface and subsurface that is yet to be understood in order to quantify its effect on the dielectric attenuation at the experiment sounding frequencies. Moreover, ridges, tectonic and shock features, may results in a complex and heterogeneous subsurface structure that can induce scattering attenuation with different amplitudes depending on the subsurface heterogeneity levels. Such attenuation phenomena's has to be accounted in the instrument design and future data analysis in order to optimize the science return, reduce mission risk and define proper operation modes. In order to address those challenges in the current performance studies and instrument design of the proposed radar sounding experiments, we present an attempt to quantify both the dielectric and scattering losses on both icy satellites, Ganymede and Europa, based on experimental dielectric characterization of relevant icy-dust mixtures samples, field work from analog environment and radar propagation simulations in parametric subsurface geophysical models representing potential geological scenarios of the two Jovian satellites. Our preliminary results suggest that the use of a dual band radar enable to overcome several of these constrains and reduces ambiguities associated subsurface interface mapping. Acknowledgement. This research is carried out by the Jet Propulsion Laboratory/Caltech, under a grant from the National Aeronautics and Space Administration.

Preferential flow paths in paraglacial catchments: first order controls on the long-term stability of 'biodiversity hotspots' in a changing climate

NASA Astrophysics Data System (ADS)

Grocott, Michael; Kettridge, Nick; Bradley, Chris; Milner, Alexander

2016-04-01

Groundwater (GW) -fed streams within paraglacial floodplains are considered 'biodiversity hotspots', given their importance as an aquatic ecosystem and role in supporting valuable riverine habitat patches within paraglacial environments. However, it is anticipated that throughout the 21st Century hydrologic regimes of paraglacial systems in arctic, sub-arctic, and alpine regions globally will experience substantial changes, as a consequence of anthropogenic climate change. Declining glacial coverage, shrinking winter snowpack, earlier spring melt, rising permafrost melt and increasing relative importance of groundwater will all cause major changes in the water balance of paraglacial catchments. This research explored the importance of preferential flow pathways (PFPs) as conduits of subsurface flow across paraglacial floodplains, and their role in sustaining 'biodiversity hotspots'. Furthermore, it considered the role of PFPs in hillslope-floodplain connectivity within paraglacial systems and the significance of colluvial deposits as a key water source to GW-fed streams on paraglacial floodplains. An intra-catchment scale field study within ungauged catchments was conducted in Denali National Park & Preserve, Alaska, during 2013 and 2014. The research utilised hydrogeomorphic and hydrochemical field techniques to address the aims outlined above. Surface infiltration and slug tests identified significant spatial heterogeneity in hydraulic conductivity (K) across the surface and subsurface of paraglacial floodplains, indicating the presence of PFPs. Furthermore, spatiotemporal variation in geochemical tracers (major ions) within surface and subsurface flow paths established the role of multiple, discrete flow paths (PFPs) in sustaining GW-fed streamflow on floodplains. Finally, hydrograph separations confirmed the significant contribution made by colluvial deposits (e.g. talus slopes) to sustaining GW-fed streamflow on paraglacial research. This research suggests PFPs are a fundamental first order control upon the occurrence of 'biodiversity hotspots' within paraglacial floodplains, and highlights their role as an important conduit for hillslope-floodplain connectivity. Given the expected changes in the hydrological dynamics of paraglacial catchments this research raises questions about the long-term stability of GW-fed streams, and whether the increasing relative importance of groundwater sources (e.g. from colluvium) can sustain flow of GW-fed streams. In addition glacial retreat and associated long-term declines in sediment yields could have negative implications for the development and renewal of PFPs across paraglacial floodplains, which would be detrimental to the persistence of 'biodiversity hotspots'.

An investigation of the sensitivity of low-field nuclear magnetic resonance to microbial growth and activity

NASA Astrophysics Data System (ADS)

Zhang, C.; Keating, K.

2014-12-01

Microbes and microbial processes play a significant role in shaping subsurface environments and are involved in applications ranging from microbially enhanced oil recovery to soil and groundwater contaminant remediation. Stimulated microbial growth in such applications could cause wide variety of changes of physical/chemical properties in the subsurface; however, due to the complexity of subsurface systems,it is difficult to monitor the growth of microbes and microbial activity in porous media. The focus of this research is to determine if low-field nuclear magnetic resonance (NMR), a method used in well logging to characterize fluids in hydrocarbon reservoirs or water in aquifers, can be used to directly detect the presence and the growth of microbes in geologic media. In this laboratory study, low-field NMR (2 MHz) relaxation measurements were collected on microbial suspensions with measured densities (i.e. biomasses), microbial pellets (live and dead), and inoculated silica. We focus on the direct contribution of microbes to the NMR signals in the absence of biomineralization. Shewanella oneidensis (MR-1), a facultative metal reducer known to play an important role in subsurface environments, were used as a model organism and were inoculated under aerobic condition. Data were collected using a CPMG pulse sequence, which was to determine the T2-distribution, and using a gradient spin-echo (PGSE) plus CPMG pulse sequence, which was used to encode diffusion properties and determine the effective diffusion-spin-spin relaxation correlation (D-T2) plot. Our data show no obvious change in the T2-distribution as S. oneidensis density varied in suspension, but show a clear distinction in the T2-distribution and D-T2 plots between live and dead cell pellets. A decrease in the T2-distribution is observed in the inoculated sand column. These results will provide a basis for understanding the effect of microbes within geologic media on low-field NMR measurements. This research is necessary to determine if NMR measurements can ultimately to be used to monitor microbial growth and activity in oil reservoirs or contaminated aquifers.

Subsurface Noble Gas Sampling Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carrigan, C. R.; Sun, Y.

2017-09-18

The intent of this document is to provide information about best available approaches for performing subsurface soil gas sampling during an On Site Inspection or OSI. This information is based on field sampling experiments, computer simulations and data from the NA-22 Noble Gas Signature Experiment Test Bed at the Nevada Nuclear Security Site (NNSS). The approaches should optimize the gas concentration from the subsurface cavity or chimney regime while simultaneously minimizing the potential for atmospheric radioxenon and near-surface Argon-37 contamination. Where possible, we quantitatively assess differences in sampling practices for the same sets of environmental conditions. We recognize that allmore » sampling scenarios cannot be addressed. However, if this document helps to inform the intuition of the reader about addressing the challenges resulting from the inevitable deviations from the scenario assumed here, it will have achieved its goal.« less

Using electrical impedance tomography to map subsurface hydraulic conductivity

DOEpatents

Berryman, James G.; Daily, William D.; Ramirez, Abelardo L.; Roberts, Jeffery J.

2000-01-01

The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

New Insights on Subsurface Imaging of Carbon Nanotubes in Polymer Composites via Scanning Electron Microscopy

NASA Technical Reports Server (NTRS)

Zhao, Minhua; Ming, Bin; Kim, Jae-Woo; Gibbons, Luke J.; Gu, Xiaohong; Nguyen, Tinh; Park, Cheol; Lillehei, Peter T.; Villarrubia, J. S.; Vladar, Andras E.;

Subsurface drip application of alternative fumigants to methyl bromide for controlling nematodes in replanted grapevines.

PubMed

Cabrera, J Alfonso; Wang, Dong; Schneider, Sally M; Hanson, Bradley D

2012-05-01

Many California grape growers use preplant fumigation to ensure uniform and healthy grapevine establishment in replant situations. A field study was conducted to evaluate the performance of subsurface drip-applied chemical alternatives to methyl bromide on plant-parasitic nematodes, plant vigor and fruit yield during the 6 year period following replanting. Subsurface drip fumigation with 1,3-dichloropropene plus chloropicrin and with iodomethane plus chloropicrin had generally similar nematicide activity as methyl bromide in three grape types, while sodium azide was less effective. The combination of 1,3-dichloropropene plus chloropicrin enhanced vine vigor similarly to methyl bromide. However, all plots treated with alternative fumigants produced less fruit yield than methyl bromide over the 4 years of evaluation. Subsurface drip fumigation with alternative chemicals to methyl bromide generally provided adequate management of plant-parasitic nematodes during the vine establishment period. However, further research is required to increase the performance of alternative chemicals against other components of the replant problem, as grape yield in vines grown in the alternative treatments was lower than in methyl bromide. Copyright © 2011 Society of Chemical Industry.

High Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Framgos, William

1999-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2002-11-20

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring, and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex

2000-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach (Song et al., 1997). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2001-06-10

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

Identification of Arbitrary Zonation in Groundwater Parameters using the Level Set Method and a Parallel Genetic Algorithm

NASA Astrophysics Data System (ADS)

Lei, H.; Lu, Z.; Vesselinov, V. V.; Ye, M.

2017-12-01

Simultaneous identification of both the zonation structure of aquifer heterogeneity and the hydrogeological parameters associated with these zones is challenging, especially for complex subsurface heterogeneity fields. In this study, a new approach, based on the combination of the level set method and a parallel genetic algorithm is proposed. Starting with an initial guess for the zonation field (including both zonation structure and the hydraulic properties of each zone), the level set method ensures that material interfaces are evolved through the inverse process such that the total residual between the simulated and observed state variables (hydraulic head) always decreases, which means that the inversion result depends on the initial guess field and the minimization process might fail if it encounters a local minimum. To find the global minimum, the genetic algorithm (GA) is utilized to explore the parameters that define initial guess fields, and the minimal total residual corresponding to each initial guess field is considered as the fitness function value in the GA. Due to the expensive evaluation of the fitness function, a parallel GA is adapted in combination with a simulated annealing algorithm. The new approach has been applied to several synthetic cases in both steady-state and transient flow fields, including a case with real flow conditions at the chromium contaminant site at the Los Alamos National Laboratory. The results show that this approach is capable of identifying the arbitrary zonation structures of aquifer heterogeneity and the hydrogeological parameters associated with these zones effectively.

Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field Scale Subsurface Research Challenge Site at Rifle, Colorado, February 2011 to January 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Philip E.; Banfield, Jill; Chandler, Darrell P.

The Rifle IFRC continued to make excellent progress during the last 12 months. As noted above, a key field experiment (Best Western) was performed during 2011 as a logical follow-on to the Super 8 field experiment preformed in 2010. In the Super 8 experiment, we successfully combined desorption and bioreduction and deployed a number of novel tracer techniques to enhance our ability to interpret the biogeochemistry of the experiment. In the Best Western experiment, we used the same experimental plot (Plot C) as was used for Super 8. The overarching objective of the Best Western field experiment was to comparedmore » the impacts of abiotic vs. biotic increases in alkalinity and to assess the mass of the sorbed pool of U(VI) at Rifle at the field scale. Both of these objectives were met. Preliminary analysis of the data indicate that the underlying biogeochemical data sets were obtained that will support a mechanistic understanding of the underlying processes, including remarkable insight into previously unrecognized microbial processes taking place during acetate amendment of the subsurface for a second time.« less

Size-dependent reactivity of magnetite nanoparticles: a field-laboratory comparison

USGS Publications Warehouse

Swindle, Andrew L.; Elwood Madden, Andrew S.; Cozzarelli, Isabelle M.; Benamara, Mourad

2014-01-01

Logistic challenges make direct comparisons between laboratory- and field-based investigations into the size-dependent reactivity of nanomaterials difficult. This investigation sought to compare the size-dependent reactivity of nanoparticles in a field setting to a laboratory analog using the specific example of magnetite dissolution. Synthetic magnetite nanoparticles of three size intervals, ∼6 nm, ∼44 nm, and ∼90 nm were emplaced in the subsurface of the USGS research site at the Norman Landfill for up to 30 days using custom-made subsurface nanoparticle holders. Laboratory analog dissolution experiments were conducted using synthetic groundwater. Reaction products were analyzed via TEM and SEM and compared to initial particle characterizations. Field results indicated that an organic coating developed on the particle surfaces largely inhibiting reactivity. Limited dissolution occurred, with the amount of dissolution decreasing as particle size decreased. Conversely, the laboratory analogs without organics revealed greater dissolution of the smaller particles. These results showed that the presence of dissolved organics led to a nearly complete reversal in the size-dependent reactivity trends displayed between the field and laboratory experiments indicating that size-dependent trends observed in laboratory investigations may not be relevant in organic-rich natural systems.

Subsurface Structure Determination of Geotermal Area in Siogung-ogung Samosir District by Using Magnetic Method

NASA Astrophysics Data System (ADS)

Tampubolon, Togi; Hutahaean, Juniar; Siregar, Suryani N. J.

2018-03-01

Underwater research often uses geomagnets. It is one of the geophysical methods for measuring magnetic field variations. This research was done to identify how the subsurface rock structure is and determine kinds of rock based on its susceptibility value in Siogung-ogung geothermal area, Pangururan, Samosir District. The tool measurement of total magnetic field called Proton Precission Magnetometer, positioning using Global Position System, and north axis determination using geological compass. Data collection was done randomly with total 51 measuring points obtained. Data analysis started with International geomagnetics Reference Field correction to obtain the total magnetic field anomaly. Then, the data analysis of total magnetic anomaly was done by using surfer program 12. To get a magnetic anomaly cross section used Magdc For Windows program. Magnetic measurement results indicated that the variation of magnetic field strength in each point with the lowest magnetic intensity value of 41785.67 nano tesla. The highest magnetic intensity value is 43140, 33. From the results of qualitative interpretation, the magnetic anomaly value is at -200.92 to 1154.45 whereas the quantitative interpretive results of model show the existence of degradation and andesitic rocks, with the value of susceptibility

Some Ecological Mechanisms to Generate Habitability in Planetary Subsurface Areas by Chemolithotrophic Communities: The Ro Tinto Subsurface Ecosystem as a Model System

NASA Astrophysics Data System (ADS)

Fernández-Remolar, David C.; Gómez, Felipe; Prieto-Ballesteros, Olga; Schelble, Rachel T.; Rodríguez, Nuria; Amiols, Ricardo

2008-02-01

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Ro Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Ro Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.

Integrating real-time subsurface hydrologic monitoring with empirical rainfall thresholds to improve landslide early warning

USGS Publications Warehouse

Mirus, Benjamin B.; Becker, Rachel E.; Baum, Rex L.; Smith, Joel B.

2018-01-01

Early warning for rainfall-induced shallow landsliding can help reduce fatalities and economic losses. Although these commonly occurring landslides are typically triggered by subsurface hydrological processes, most early warning criteria rely exclusively on empirical rainfall thresholds and other indirect proxies for subsurface wetness. We explore the utility of explicitly accounting for antecedent wetness by integrating real-time subsurface hydrologic measurements into landslide early warning criteria. Our efforts build on previous progress with rainfall thresholds, monitoring, and numerical modeling along the landslide-prone railway corridor between Everett and Seattle, Washington, USA. We propose a modification to a previously established recent versus antecedent (RA) cumulative rainfall thresholds by replacing the antecedent 15-day rainfall component with an average saturation observed over the same timeframe. We calculate this antecedent saturation with real-time telemetered measurements from five volumetric water content probes installed in the shallow subsurface within a steep vegetated hillslope. Our hybrid rainfall versus saturation (RS) threshold still relies on the same recent 3-day rainfall component as the existing RA thresholds, to facilitate ready integration with quantitative precipitation forecasts. During the 2015–2017 monitoring period, this RS hybrid approach has an increase of true positives and a decrease of false positives and false negatives relative to the previous RA rainfall-only thresholds. We also demonstrate that alternative hybrid threshold formats could be even more accurate, which suggests that further development and testing during future landslide seasons is needed. The positive results confirm that accounting for antecedent wetness conditions with direct subsurface hydrologic measurements can improve thresholds for alert systems and early warning of rainfall-induced shallow landsliding.

Some ecological mechanisms to generate habitability in planetary subsurface areas by chemolithotrophic communities: the Río Tinto subsurface ecosystem as a model system.

PubMed

Fernández-Remolar, David C; Gómez, Felipe; Prieto-Ballesteros, Olga; Schelble, Rachel T; Rodríguez, Nuria; Amils, Ricardo

2008-02-01

Chemolithotrophic communities that colonize subsurface habitats have great relevance for the astrobiological exploration of our Solar System. We hypothesize that the chemical and thermal stabilization of an environment through microbial activity could make a given planetary region habitable. The MARTE project ground-truth drilling campaigns that sampled cryptic subsurface microbial communities in the basement of the Río Tinto headwaters have shown that acidic surficial habitats are the result of the microbial oxidation of pyritic ores. The oxidation process is exothermic and releases heat under both aerobic and anaerobic conditions. These microbial communities can maintain the subsurface habitat temperature through storage heat if the subsurface temperature does not exceed their maximum growth temperature. In the acidic solutions of the Río Tinto, ferric iron acts as an effective buffer for controlling water pH. Under anaerobic conditions, ferric iron is the oxidant used by microbes to decompose pyrite through the production of sulfate, ferrous iron, and protons. The integration between the physical and chemical processes mediated by microorganisms with those driven by the local geology and hydrology have led us to hypothesize that thermal and chemical regulation mechanisms exist in this environment and that these homeostatic mechanisms could play an essential role in creating habitable areas for other types of microorganisms. Therefore, searching for the physicochemical expression of extinct and extant homeostatic mechanisms through physical and chemical anomalies in the Mars crust (i.e., local thermal gradient or high concentration of unusual products such as ferric sulfates precipitated out from acidic solutions produced by hypothetical microbial communities) could be a first step in the search for biological traces of a putative extant or extinct Mars biosphere.

The influence of subsurface porosity and bedrock composition on ecosystem productivity and drought resilience in the Sierra Nevada Batholith, California

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Callahan, R. P.; Goulden, M.; Pasquet, S.; Flinchum, B. A.; Taylor, N. J.; Holbrook, W. S.

2017-12-01

The availability of water and nutrients in soil and weathered rock influences the distribution of Earth's terrestrial life and regulates ecosystem vulnerability to land use and climate change. We explored these relationships by combining geochemical and geophysical measurements at three mid-elevation sites in the Sierra Nevada, California. Forest cover correlates strongly with bedrock composition across the sites, implying strong lithologic control on the ecosystem. We evaluated two hypotheses about bedrock-ecosystem connections: 1) that bedrock composition influences vegetation by moderating plant-essential nutrient supply; and 2) that bedrock composition influences the degree of subsurface weathering, which influences vegetation by controlling subsurface water-storage capacity. To quantify subsurface water-holding capacity, we used seismic refraction surveys to infer gradients in P and S-wave velocity structure, which reveal variations in porosity when coupled together in a Hertz-Mindlin rock-physics model. We combined the geophysical data on porosity with bedrock bulk geochemistry measured in previous work to evaluate the influence of water-holding capacity and nutrient supply on ecosystem productivity, which we quantified using remote sensing. Our results show that more than 80% of the variance in ecosystem productivity can be explained by differences in bedrock phosphorus concentration and subsurface porosity, with phosphorus content being the dominant explanatory variable. This suggests that bedrock composition exerts a strong bottom-up control on ecosystem productivity through its influence on nutrient supply and weathering susceptibility, which in turn influences porosity. We show that vegetation vulnerability to drought stress and mortality can be explained in part by variations in subsurface water-holding capacity and rock-derived nutrient supply.

Development of stream-subsurface flow module in sub-daily simulation of Escherichia coli using SWAT

NASA Astrophysics Data System (ADS)

Kim, Minjeong; Boithias, Laurie; Cho, Kyung Hwa; Silvera, Norbert; Thammahacksa, Chanthamousone; Latsachack, Keooudone; Rochelle-Newall, Emma; Sengtaheuanghoung, Oloth; Pierret, Alain; Pachepsky, Yakov A.; Ribolzi, Olivier

2017-04-01

Water contaminated with pathogenic bacteria poses a large threat to public health, especially in the rural areas in the tropics where sanitation and drinking water facilities are often lacking. Several studies have used the Soil and Water Assessment Tool (SWAT) to predict the export of in-stream bacteria at a watershed-scale. However, SWAT is limited to in-stream processes, such as die-off, resuspension and, deposition; and it is usually implemented on a daily time step using the SCS Curve Number method, making it difficult to explore the dynamic fate and transport of bacteria during short but intense events such as flash floods in tropical humid montane headwaters. To address these issues, this study implemented SWAT on an hourly time step using the Green-Ampt infiltration method, and tested the effects of subsurface flow (LATQ+GWQ in SWAT) on bacterial dynamics. We applied the modified SWAT model to the 60-ha Houay Pano catchment in Northern Laos, using sub-daily rainfall and discharge measurements, electric conductivity-derived fractions of overland and subsurface flows, suspended sediments concentrations, and the number of fecal indicator organism Escherichia coli monitored at the catchment outlet from 2011 to 2013. We also took into account land use change by delineating the watershed with the 3-year composite land use map. The results show that low subsurface flow of less than 1 mm recovered the underestimation of E. coli numbers during the dry season, while high subsurface flow caused an overestimation during the wet season. We also found that it is more reasonable to apply the stream-subsurface flow interaction to simulate low in-stream bacteria counts. Using fecal bacteria to identify and understand the possible interactions between overland and subsurface flows may well also provide some insight into the fate of other bacteria, such as those involved in biogeochemical fluxes both in-stream and in the adjacent soils and hyporheic zones.

Characterizing phosphorus dynamics in tile-drained agricultural fieldsof eastern Wisconsin

USGS Publications Warehouse

Madison, Allison; Ruark, Matthew; Stuntebeck, Todd D.; Komiskey, Matthew J.; Good, Laura W.; Drummy, Nancy; Cooley, Eric

2014-01-01

Artificial subsurface drainage provides an avenue for the rapid transfer of phosphorus (P) from agricultural fields to surface waters. This is of particular interest in eastern Wisconsin, where there is a concentrated population of dairy farms and high clay content soils prone to macropore development. Through collaboration with private landowners, surface and tile drainage was measured and analyzed for dissolved reactive P (DRP) and total P (TP) losses at four field sites in eastern Wisconsin between 2005 and 2009. These sites, which received frequent manure applications, represent a range of crop management practices which include: two chisel plowed corn fields (CP1, CP2), a no-till corn–soybean field (NT), and a grazed pasture (GP). Subsurface drainage was the dominant pathway of water loss at each site accounting for 66–96% of total water discharge. Average annual flow-weighted (FW) TP concentrations were 0.88, 0.57, 0.21, and 1.32 mg L−1 for sites CP1, CP2, NT, and GP, respectively. Low TP concentrations at the NT site were due to tile drain interception of groundwater flow where large volumes of tile drainage water diluted the FW-TP concentrations. Subsurface pathways contributed between 17% and 41% of the TP loss across sites. On a drainage event basis, total drainage explained between 36% and 72% of the event DRP loads across CP1, CP2, and GP; there was no relationship between event drainflow and event DRP load at the NT site. Manure applications did not consistently increase P concentrations in drainflow, but annual FW-P concentrations were greater in years receiving manure applications compared to years without manure application. Based on these field measures, P losses from tile drainage must be integrated into field level P budgets and P loss calculations on heavily manured soils, while also acknowledging the unique drainage patterns observed in eastern Wisconsin.

Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field-Scale Subsurface Research Challenge Site at Rifle, Colorado, Quality Assurance Project Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fix, N. J.

The U.S. Department of Energy (DOE) is cleaning up and/or monitoring large, dilute plumes contaminated by metals, such as uranium and chromium, whose mobility and solubility change with redox status. Field-scale experiments with acetate as the electron donor have stimulated metal-reducing bacteria to effectively remove uranium [U(VI)] from groundwater at the Uranium Mill Tailings Site in Rifle, Colorado. The Pacific Northwest National Laboratory and a multidisciplinary team of national laboratory and academic collaborators has embarked on a research proposed for the Rifle site, the object of which is to gain a comprehensive and mechanistic understanding of the microbial factors andmore » associated geochemistry controlling uranium mobility so that DOE can confidently remediate uranium plumes as well as support stewardship of uranium-contaminated sites. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by the Rifle Integrated Field-Scale Subsurface Research Challenge Project.« less

Public health assessment for Commencement Bay, South Tacoma Field, Tacoma, Pierce County, Washington, Region 10. Cerclis No. WAD980724173 (A/K/A Commencement Bay, South Tacoma Channel, Tacoma, Pierce County, Washington, Region 10. Cerclis No. WAD980726301). Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The Commencement Bay, South Tacoma Field site occupies 260 acres of land located in the southwestern section of the city of Tacoma in Pierce County, Washington. The South Tacoma Field site poses a public health hazard to trespassers who repeatedly ingest contaminated surface soils, surface water, and sediment during recreational activities at the site. Exposure to the contaminants arsenic, copper, lead, manganese, as well as polychlorinated biphenyl and polycyclic aromatic hydrocarbon compounds may have occurred in the past, may be presently occurring, and may occur in the future, which could result in noncarcinogenic and carcinogenic health effects. Potentially, the sitemore » can pose a public health hazard through exposure to groundwater and subsurface soil contaminants that could cause adverse health effects. Additionally, should contruction/excavation uncover contaminated subsurface soils, workers as well as recreationalists/trespassers may be exposed.« less

Higher and lowest order mixed finite element approximation of subsurface flow problems with solutions of low regularity

NASA Astrophysics Data System (ADS)

Bause, Markus

2008-02-01

In this work we study mixed finite element approximations of Richards' equation for simulating variably saturated subsurface flow and simultaneous reactive solute transport. Whereas higher order schemes have proved their ability to approximate reliably reactive solute transport (cf., e.g. [Bause M, Knabner P. Numerical simulation of contaminant biodegradation by higher order methods and adaptive time stepping. Comput Visual Sci 7;2004:61-78]), the Raviart- Thomas mixed finite element method ( RT0) with a first order accurate flux approximation is popular for computing the underlying water flow field (cf. [Bause M, Knabner P. Computation of variably saturated subsurface flow by adaptive mixed hybrid finite element methods. Adv Water Resour 27;2004:565-581, Farthing MW, Kees CE, Miller CT. Mixed finite element methods and higher order temporal approximations for variably saturated groundwater flow. Adv Water Resour 26;2003:373-394, Starke G. Least-squares mixed finite element solution of variably saturated subsurface flow problems. SIAM J Sci Comput 21;2000:1869-1885, Younes A, Mosé R, Ackerer P, Chavent G. A new formulation of the mixed finite element method for solving elliptic and parabolic PDE with triangular elements. J Comp Phys 149;1999:148-167, Woodward CS, Dawson CN. Analysis of expanded mixed finite element methods for a nonlinear parabolic equation modeling flow into variably saturated porous media. SIAM J Numer Anal 37;2000:701-724]). This combination might be non-optimal. Higher order techniques could increase the accuracy of the flow field calculation and thereby improve the prediction of the solute transport. Here, we analyse the application of the Brezzi- Douglas- Marini element ( BDM1) with a second order accurate flux approximation to elliptic, parabolic and degenerate problems whose solutions lack the regularity that is assumed in optimal order error analyses. For the flow field calculation a superiority of the BDM1 approach to the RT0 one is observed, which however is less significant for the accompanying solute transport.

Locating S-wave sources for the SPE-5 explosion using time reversal methods and a close-in, 1000 sensor network

NASA Astrophysics Data System (ADS)

Myers, S. C.; Pitarka, A.; Mellors, R. J.

2016-12-01

The Source Physics Experiment (SPE) is producing new data to study the generation of seismic waves from explosive sources. Preliminary results show that far-field S-waves are generated both within the non-elastic volume surrounding explosive sources and by P- to S-wave scattering. The relative contribution of non-elastic phenomenology and elastic-wave scattering to far-field S-waves has been debated for decades, and numerical simulations based on the SPE experiments are addressing this question. The match between observed and simulated data degrades with event-station distance and with increasing time in each seismogram. This suggests that a more accurate model of subsurface elastic properties could result in better agreement between observed and simulated seismograms. A detailed model of subsurface structure has been developed using geologic maps and the extensive database of borehole logs, but uncertainty in structural details remains high. The large N instrument deployment during the SPE-5 experiment offers an opportunity to use time-reversal techniques to back project the wave field into the subsurface to locate significant sources of scattered energy. The large N deployment was nominally 1000, 5 Hz sensors (500 Z and 500 3C geophones) deployed in a roughly rectangular array to the south and east of the SPE-5 shot. Sensor spacing was nominally 50 meters in the interior portion of the array and 100 meters in the outer region, with two dense lines at 25 m spacing. The array covers the major geologic boundary between the Yucca Flat basin and the granitic Climax Stock in which the SPE experiments have been conducted. Improved mapping of subsurface scatterers is expected to result in better agreement between simulated and observed seismograms and aid in our understanding of S-wave generation from explosions. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

Jupiter Icy Moons Explorer: mission status after the Definition Phase

NASA Astrophysics Data System (ADS)

Titov, Dmitri; Barabash, Stas; Bruzzone, Lorenzo; Dougherty, Michele; Erd, Christian; Fletcher, Leigh; Gare, Philippe; Gladstone, Randall; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Langevin, Yves; Palumbo, Pasquale; Piccioni, Giuseppe; Sarri, Giuseppe; Wahlund, Jan-Erik; Witasse, Olivier

2015-04-01

JUpiter ICy moons Explorer (JUICE), the ESA first large-class mission within the Cosmic Vision Program 2015-2025, was adopted in November 2014. The mission will perform detailed investigations of Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. The overarching theme for JUICE is: The emergence of habitable worlds around gas giants. At Ganymede, the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions will be elucidated. JUICE will study the moons' interactions with the magnetosphere, gravitational coupling and long-term tidal evolution of the Galilean satellites. JUICE highly capable scientific payload includes 10 state-of-the-art instruments onboard the spacecraft plus one experiment that uses the spacecraft telecommunication system with ground-based radio telescopes. The remote sensing package includes a high-resolution multi-band visible imager (JANUS) and spectro-imaging capabilities from the ultraviolet to the sub-millimetre wavelengths (MAJIS, UVS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the surface and subsurface of the moons, and a radio science experiment (3GM) to probe the atmospheres of Jupiter and its satellites and to perform measurements of the gravity fields. An in situ package comprises a powerful particle environment package (PEP), a magnetometer (J-MAG) and a radio and plasma wave instrument (RPWI), including electric fields sensors and a Langmuir probe. An experiment (PRIDE) using ground-based Very-Long-Baseline Interferometry (VLBI) will provide precise determination of the moons ephemerides. The mission scenario will include a Jovian tour with multiple flybys of Callisto and Ganymede, the phase with more than 20 degrees inclination orbits, and two Europa flybys. The Ganymede tour will include high (5000 km) and low (500 km) almost polar orbits around the moon. The mission scenario has evolved slightly during the definition phase, reassuring that the mission will still be able to fulfil all major science objectives. The talk will give an overview of the mission status at the end of the definition phase, focusing on the evolution of science performance and payload synergies in achieving the mission goals.

Lessons Learned from Assimilating Altimeter Data into a Coupled General Circulation Model with the GMAO Augmented Ensemble Kalman Filter

NASA Technical Reports Server (NTRS)

Keppenne, Christian; Vernieres, Guillaume; Rienecker, Michele; Jacob, Jossy; Kovach, Robin

2011-01-01

Satellite altimetry measurements have provided global, evenly distributed observations of the ocean surface since 1993. However, the difficulties introduced by the presence of model biases and the requirement that data assimilation systems extrapolate the sea surface height (SSH) information to the subsurface in order to estimate the temperature, salinity and currents make it difficult to optimally exploit these measurements. This talk investigates the potential of the altimetry data assimilation once the biases are accounted for with an ad hoc bias estimation scheme. Either steady-state or state-dependent multivariate background-error covariances from an ensemble of model integrations are used to address the problem of extrapolating the information to the sub-surface. The GMAO ocean data assimilation system applied to an ensemble of coupled model instances using the GEOS-5 AGCM coupled to MOM4 is used in the investigation. To model the background error covariances, the system relies on a hybrid ensemble approach in which a small number of dynamically evolved model trajectories is augmented on the one hand with past instances of the state vector along each trajectory and, on the other, with a steady state ensemble of error estimates from a time series of short-term model forecasts. A state-dependent adaptive error-covariance localization and inflation algorithm controls how the SSH information is extrapolated to the sub-surface. A two-step predictor corrector approach is used to assimilate future information. Independent (not-assimilated) temperature and salinity observations from Argo floats are used to validate the assimilation. A two-step projection method in which the system first calculates a SSH increment and then projects this increment vertically onto the temperature, salt and current fields is found to be most effective in reconstructing the sub-surface information. The performance of the system in reconstructing the sub-surface fields is particularly impressive for temperature, but not as satisfactory for salt.

Modeling Aspect Controlled Formation of Seasonally Frozen Ground on Montane Hillslopes: a Case Study from Gordon Gulch, Colorado

NASA Astrophysics Data System (ADS)

Rush, M.; Rajaram, H.; Anderson, R. S.; Anderson, S. P.

2017-12-01

The Intergovernmental Panel on Climate Change (2013) warns that high-elevation ecosystems are extremely vulnerable to climate change due to short growing seasons, thin soils, sparse vegetation, melting glaciers, and thawing permafrost. Many permafrost-free regions experience seasonally frozen ground. The spatial distribution of frozen soil exerts a strong control on subsurface flow and transport processes by reducing soil permeability and impeding infiltration. Accordingly, evolution of the extent and duration of frozen ground may alter streamflow seasonality, groundwater flow paths, and subsurface storage, presenting a need for coupled thermal-hydrologic models to project hydrologic responses to climate warming in high-elevation regions. To be useful as predictive tools, such models should incorporate the heterogeneity of solar insolation, vegetation, and snowpack dynamics. We present a coupled thermal-hydrologic modeling study against the backdrop of field observations from Gordon Gulch, a seasonally snow-covered montane catchment in the Colorado Front Range in the Boulder Creek Critical Zone Observatory. The field site features two instrumented hillslopes with opposing aspects: the snowpack on the north-facing slope persists throughout much of the winter season, while the snowpack on the south-facing slope is highly ephemeral. We implemented a surface energy balance and snowpack accumulation and ablation model that is coupled to the subsurface flow and transport code PFLOTRAN-ICE to predict the hydrologic consequences of aspect-controlled frozen soil formation during water years 2013-2016. Preliminary model results demonstrate the occurrence of seasonally-frozen ground on the north-facing slope that directs snowmelt to the stream by way of shallow subsurface flow paths. The absence of persistently frozen ground on the south-facing slope allows deeper infiltration of snowmelt recharge. The differences in subsurface flow paths also suggest strong aspect-controlled heterogeneities in nitrate export and differences in geomorphic processes such as frost creep.

Virtual experiments: a new approach for improving process conceptualization in hillslope hydrology

NASA Astrophysics Data System (ADS)

Weiler, Markus; McDonnell, Jeff

2004-01-01

We present an approach for process conceptualization in hillslope hydrology. We develop and implement a series of virtual experiments, whereby the interaction between water flow pathways, source and mixing at the hillslope scale is examined within a virtual experiment framework. We define these virtual experiments as 'numerical experiments with a model driven by collective field intelligence'. The virtual experiments explore the first-order controls in hillslope hydrology, where the experimentalist and modeler work together to cooperatively develop and analyze the results. Our hillslope model for the virtual experiments (HillVi) in this paper is based on conceptualizing the water balance within the saturated and unsaturated zone in relation to soil physical properties in a spatially explicit manner at the hillslope scale. We argue that a virtual experiment model needs to be able to capture all major controls on subsurface flow processes that the experimentalist might deem important, while at the same time being simple with few 'tunable parameters'. This combination makes the approach, and the dialog between experimentalist and modeler, a useful hypothesis testing tool. HillVi simulates mass flux for different initial conditions under the same flow conditions. We analyze our results in terms of an artificial line source and isotopic hydrograph separation of water and subsurface flow. Our results for this first set of virtual experiments showed how drainable porosity and soil depth variability exert a first order control on flow and transport at the hillslope scale. We found that high drainable porosity soils resulted in a restricted water table rise, resulting in more pronounced channeling of lateral subsurface flow along the soil-bedrock interface. This in turn resulted in a more anastomosing network of tracer movement across the slope. The virtual isotope hydrograph separation showed higher proportions of event water with increasing drainable porosity. When combined with previous experimental findings and conceptualizations, virtual experiments can be an effective way to isolate certain controls and examine their influence over a range of rainfall and antecedent wetness conditions.

The subsurface geology of Río Tinto: material examined during a simulated Mars drilling mission for the Mars Astrobiology Research and Technology Experiment (MARTE).

PubMed

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L; Bell, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R

2008-10-01

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undisclosed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

The Subsurface Geology of Río Tinto: Material Examined During a Simulated Mars Drilling Mission for the Mars Astrobiology Research and Technology Experiment (MARTE)

NASA Astrophysics Data System (ADS)

Prieto-Ballesteros, Olga; Martínez-Frías, Jesús; Schutt, John; Sutter, Brad; Heldmann, Jennifer L.; Bell Johnson, Mary Sue; Battler, Melissa; Cannon, Howard; Gómez-Elvira, Javier; Stoker, Carol R.

2008-10-01

The 2005 Mars Astrobiology Research and Technology Experiment (MARTE) project conducted a simulated 1-month Mars drilling mission in the Río Tinto district, Spain. Dry robotic drilling, core sampling, and biological and geological analytical technologies were collectively tested for the first time for potential use on Mars. Drilling and subsurface sampling and analytical technologies are being explored for Mars because the subsurface is the most likely place to find life on Mars. The objectives of this work are to describe drilling, sampling, and analytical procedures; present the geological analysis of core and borehole material; and examine lessons learned from the drilling simulation. Drilling occurred at an undis closed location, causing the science team to rely only on mission data for geological and biological interpretations. Core and borehole imaging was used for micromorphological analysis of rock, targeting rock for biological analysis, and making decisions regarding the next day's drilling operations. Drilling reached 606 cm depth into poorly consolidated gossan that allowed only 35% of core recovery and contributed to borehole wall failure during drilling. Core material containing any indication of biology was sampled and analyzed in more detail for its confirmation. Despite the poorly consolidated nature of the subsurface gossan, dry drilling was able to retrieve useful core material for geological and biological analysis. Lessons learned from this drilling simulation can guide the development of dry drilling and subsurface geological and biological analytical technologies for future Mars drilling missions.

Hydrologic connectivity of geographically isolated wetlands to surface water systems

NASA Astrophysics Data System (ADS)

Creed, I. F.; Ameli, A.

2016-12-01

Hydrologic connectivity of wetlands is poorly characterized and understood. Our inability to quantify this connectivity compromises our understanding of the potential impacts of land use (e.g., wetland drainage) and climate changes on watershed structure, function and water supplies. We develop a computationally efficient physically-based subsurface-surface hydrological model to map both the subsurface and surface hydrologic connectivity of geographically isolated wetlands (i.e., wetlands without surface outlets) and explore the time and length variations in these connections to a river within the Prairie Pothole Region of North America. Despite a high density of geographically isolated wetlands, modeled connections show that these wetlands are not hydrologically isolated. Hydrologic subsurface connectivity differs significantly from surface connectivity in terms of timing and length of connections. Slow subsurface connections between wetlands and the downstream river originate from wetlands throughout the watershed, whereas fast surface connections were limited to large events and originate from wetlands located near the river. Results also suggest that prioritization of protection of wetlands that relies on shortest distance of wetland to the river or surface connections alone can lead to unintended consequences in terms of loss of attending wetland ecosystem functions, services and their benefits to society. This modeling approach provides first ever insight on the nature of geographically isolated wetland subsurface and surface hydrological connections to rivers, and can provide guidance on the development of watershed management and conservation plans (e.g., wetlands drainage/restoration) under different climate and land management scenarios.

The Limits of Life in the Deep Subsurface - Implications for the Origin of Life

NASA Astrophysics Data System (ADS)

Baross, John

2013-06-01

There are very few environments on Earth where life is absent. Microbial life has proliferated into habitats that span nearly every imaginable physico-chemical variable. Only the availability of liquid water and temperature are known to prevent the growth of organisms. The other extreme physical and chemical variables, such as pH, pressure, high concentrations of solutes, damaging radiation, and toxic metals, are life-prohibiting factors for most organisms but not for all. The deep subsurface environments span all of the extreme conditions encountered by life including habitat conditions not yet explored, such as those that combine high temperature, high and low pH and extreme pressures. Some of the ``extremophile'' microorganisms inhabiting the deep subsurface environments have been shown to be among the most ``ancient'' of extant life. Their genomes and physiologies have led to a broader understanding of the geological settings of early life, the most ancient energy pathways, and the importance of water/rock interactions and tectonics in the origin and early evolution of life. The case can now be made that deep subsurface environments contributed to life's origin and provided the habitat(s) for the earliest microbial communities. However, there is much more to be done to further our understanding on the role of moderate to high pressures and temperatures on the chemical and biochemical ``steps'' leading to life, and on the evolution and physiology of both ancient and present-day subsurface microbial communities.

Subsurface Exploration Methods for Soft Ground Rapid Transit Tunnels : Volume 1. Sections 1-6 and references.

DOT National Transportation Integrated Search

1976-04-01

The objectives of the Urban Mass Transportation Administration (UMTA) Tunneling Program are to lower subway construction costs and reduce construction hazards and damage to the environment. Some measure of each of these objectives for bored tunnels a...

Improved correlation between Texas cone penetrometer blow count and undrained shear strength of soft clays.

DOT National Transportation Integrated Search

2009-01-01

The objective of this project was to develop an improved correlation between Texas Cone Penetrometer (TCP) : blow count and undrained shear strength for soft, clay soils in the upper approximately 30 feet of the ground. Subsurface : explorations were...

Subsurface metabolic potential on the Costa Rican Margin

NASA Astrophysics Data System (ADS)

Biddle, J.; Leon, Z. R.; Martino, A. J.; Bousses, K.; House, C. H.

2017-12-01

The distribution of archaea and bacteria and their associated metabolic abilities in the deep subseafloor are poorly understood. In order to explore this, we focused on samples from the Costa Rica margin IODP Expedition 334. The microbial community was analyzed via metagenomics in two different sites at multiple depths. At Site 1378, samples are from 2 meters below the sea floor (mbsf), 33 mbsf and 93 mbsf, and at Site 1379 from 22 mbsf to 45 mbsf. Whole community analysis of conserved gene markers in the metagenome show that the microbial community varies with depth, and drastically differs between the two geographically close sites. Thirty-two genomes were recovered from the metagenomic data with more than 30% completion. Archaea make 49% of all genomes recovered and over 90% of these recovered genomes belong to recently discovered and poorly characterized groups of Archaea. This study explored the relative dynamics of microbial communities in the deep biosphere and presents the metabolic potential of distinct subsurface biosphere archaeal groups.

A High-Sensitivity Broad-Band Seismic Sensor for Shallow Seismic Sounding of the Lunar Regolith

NASA Technical Reports Server (NTRS)

Pike, W. Thomas; Standley, Ian M.; Banerdt, W. Bruce

2005-01-01

The recently undertaken Space Exploration Initiative has prompted a renewed interest in techniques for characterizing the surface and shallow subsurface (0-10s of meters depth) of the Moon. There are several reasons for this: First, there is an intrinsic scientific interest in the subsurface structure. For example the stratigraphy, depth to bedrock, density/porosity, and block size distribution all have implications for the formation of, and geological processes affecting the surface, such as sequential crater ejecta deposition, impact gardening, and seismic settling. In some permanently shadowed craters there may be ice deposits just below the surface. Second, the geotechnical properties of the lunar surface layers are of keen interest to future mission planners. Regolith thickness, strength, density, grain size and compaction will affect construction of exploration infrastructure in terms of foundation strength and stability, ease of excavation, radiation shielding effectiveness, as well as raw material handling and processing techniques for resource extraction.

Groundwater and organic chemicals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dawson, H.E.

1995-12-01

Groundwater is a major source of drinking water for many communities. Unfortunately, organic chemicals such as dry cleaning fluids, solvent, fuels, and pesticides have contaminated groundwater in many areas, rendering the groundwater useless as a drinking water resource. In many cases, the groundwater cannot be cleaned up with current technologies, particularly if the groundwater has been contaminated with immiscible (low solubility) organic liquids. In this talk, I will describe the path I have followed from geologist to geochemist and finally to environmental engineer. As a geologist, I studied the chemistry of rock metamorphosis. As a geochemist, I explored for goldmore » and other metals. Now as an environmental engineer, I investigate the behavior of organic liquids in the subsurface. While these fields all appear very different, in reality I have always focused on the interaction of rocks or sediments with the fluids with which they come in contact.« less

Planetary Geochemistry Techniques: Probing In-Situ with Neutron and Gamma Rays (PING) Instrument

NASA Technical Reports Server (NTRS)

Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S.; Lin, L.; McClanahan, T.; Nankung, M.; Nowicki, S.; Schweitzer, J.;

Antarctic analogues for Mars exploration: a Raman spectroscopic study of biogeological signatures

NASA Astrophysics Data System (ADS)

Edwards, Howell G. M.; Moody, Caroline A.; Jorge Villar, Susana E.; Dickensheets, David L.; Wynn-Williams, David D.

2004-03-01

There is now much interest in the construction of portable Raman systems for the analysis of cyanobacterial and lichen communities in the field; to this extent, Raman spectra obtained with laboratory-based systems operating at different wavelengths have been evaluated for potential fieldwork applications of miniaturized units. Selected test specimens of the cyanobacterial Nostoc commune, epilithic lichens Acarospora chlorophana, and Caloplaca saxicola and the endolithic Chroococcidiopsis from Antarctic sites have been examined in the present preliminary studies. Although some organisms gave useable Raman spectra with short-wavelength lasers, 1064 nm was the only excitation that was consistently excellent for all organisms. We conclude that a miniaturized Raman spectrometer, operating at layer wavelength excitation, is the optimal instrument for in situ studies of pigmented communities at the limits of life on Earth. This has practical potential for the quest for biomolecules residual from any former surface or subsurface life on Mars.

Digital Core Modelling for Clastic Oil and Gas Reservoir

NASA Astrophysics Data System (ADS)

Belozerov, I.; Berezovsky, V.; Gubaydullin, M.; Yur’ev, A.

2018-05-01

"Digital core" is a multi-purpose tool for solving a variety of tasks in the field of geological exploration and production of hydrocarbons at various stages, designed to improve the accuracy of geological study of subsurface resources, the efficiency of reproduction and use of mineral resources, as well as applying the results obtained in production practice. The actuality of the development of the "Digital core" software is that even a partial replacement of natural laboratory experiments with mathematical modelling can be used in the operative calculation of reserves in exploratory drilling, as well as in the absence of core material from wells. Or impossibility of its research by existing laboratory methods (weakly cemented, loose, etc. rocks). 3D-reconstruction of the core microstructure can be considered as a cheap and least time-consuming method for obtaining petrophysical information about the main filtration-capacitive properties and fluid motion in reservoir rocks.

Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K. M.; Davis, J. A.; Bargar, J.

2011-10-15

Reductive biostimulation is currently being explored as a possible remediation strategy for uranium (U) contaminated groundwater, and is currently being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance and depends upon a variety of factors, including rate and mechanism of reduction, mineral associations in the subsurface, and propensity for oxidation. To address these factors, several approaches were used to evaluate the redox sensitivity of U: measurement of the rate of oxidative dissolution of biogenic uraninite (UO{sub 2(s)}) deployed in groundwater at Rifle, characterizationmore » of a zone of natural bioreduction exhibiting relevant reduced mineral phases, and laboratory studies of the oxidative capacity of Fe(III) and reductive capacity of Fe(II) with regard to U(IV) and U(VI), respectively.« less

Synthetic Sediments and Stochastic Groundwater Hydrology

NASA Astrophysics Data System (ADS)

Wilson, J. L.

2002-12-01

For over twenty years the groundwater community has pursued the somewhat elusive goal of describing the effects of aquifer heterogeneity on subsurface flow and chemical transport. While small perturbation stochastic moment methods have significantly advanced theoretical understanding, why is it that stochastic applications use instead simulations of flow and transport through multiple realizations of synthetic geology? Allan Gutjahr was a principle proponent of the Fast Fourier Transform method for the synthetic generation of aquifer properties and recently explored new, more geologically sound, synthetic methods based on multi-scale Markov random fields. Focusing on sedimentary aquifers, how has the state-of-the-art of synthetic generation changed and what new developments can be expected, for example, to deal with issues like conceptual model uncertainty, the differences between measurement and modeling scales, and subgrid scale variability? What will it take to get stochastic methods, whether based on moments, multiple realizations, or some other approach, into widespread application?

Transient Electromagnetic Soundings Near Great Sand Dunes National Park and Preserve, San Luis Valley, Colorado (2006 Field Season)

USGS Publications Warehouse

Fitterman, David V.; de Sozua Filho, Oderson A.

2009-01-01

Time-domain electromagnetic (TEM) soundings were made near Great Sand Dunes National Park and Preserve in the San Luis Valley of southern Colorado to obtain subsurface information of use to hydrologic modeling. Seventeen soundings were made to the east and north of the sand dunes. Using a small loop TEM system, maximum exploration depths of about 75 to 150 m were obtained. In general, layered earth interpretations of the data found that resistivity decreases with depth. Comparison of soundings with geologic logs from nearby wells found that zones logged as having increased clay content usually corresponded with a significant resistivity decrease in the TEM determined model. This result supports the use of TEM soundings to map the location of the top of the clay unit deposited at the bottom of the ancient Lake Alamosa that filled the San Luis Valley from Pliocene to middle Pleistocene time.

The Characterization of Biosignatures in Caves Using an Instrument Suite

NASA Astrophysics Data System (ADS)

Uckert, Kyle; Chanover, Nancy J.; Getty, Stephanie; Voelz, David G.; Brinckerhoff, William B.; McMillan, Nancy; Xiao, Xifeng; Boston, Penelope J.; Li, Xiang; McAdam, Amy; Glenar, David A.; Chavez, Arriana

2017-12-01

The search for life and habitable environments on other Solar System bodies is a major motivator for planetary exploration. Due to the difficulty and significance of detecting extant or extinct extraterrestrial life in situ, several independent measurements from multiple instrument techniques will bolster the community's confidence in making any such claim. We demonstrate the detection of subsurface biosignatures using a suite of instrument techniques including IR reflectance spectroscopy, laser-induced breakdown spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy. We focus our measurements on subterranean calcium carbonate field samples, whose biosignatures are analogous to those that might be expected on some high-interest astrobiology targets. In this work, we discuss the feasibility and advantages of using each of the aforementioned instrument techniques for the in situ search for biosignatures and present results on the autonomous characterization of biosignatures using multivariate statistical analysis techniques.

Improving Thin Bed Identification in Sarawak Basin Field using Short Time Fourier Transform Half Cepstrum (STFTHC) method

NASA Astrophysics Data System (ADS)

Nizarul, O.; Hermana, M.; Bashir, Y.; Ghosh, D. P.

2016-02-01

In delineating complex subsurface geological feature, broad band of frequencies are needed to unveil the often hidden features of hydrocarbon basin such as thin bedding. The ability to resolve thin geological horizon on seismic data is recognized to be a fundamental importance for hydrocarbon exploration, seismic interpretation and reserve prediction. For thin bedding, high frequency content is needed to enable tuning, which can be done by applying the band width extension technique. This paper shows an application of Short Time Fourier Transform Half Cepstrum (STFTHC) method, a frequency bandwidth expansion technique for non-stationary seismic signal in increasing the temporal resolution to uncover thin beds and improve characterization of the basin. A wedge model and synthetic seismic data is used to quantify the algorithm as well as real data from Sarawak basin were used to show the effectiveness of this method in enhancing the resolution.

The Characterization of Biosignatures in Caves Using an Instrument Suite.

PubMed

Uckert, Kyle; Chanover, Nancy J; Getty, Stephanie; Voelz, David G; Brinckerhoff, William B; McMillan, Nancy; Xiao, Xifeng; Boston, Penelope J; Li, Xiang; McAdam, Amy; Glenar, David A; Chavez, Arriana

2017-12-01

The search for life and habitable environments on other Solar System bodies is a major motivator for planetary exploration. Due to the difficulty and significance of detecting extant or extinct extraterrestrial life in situ, several independent measurements from multiple instrument techniques will bolster the community's confidence in making any such claim. We demonstrate the detection of subsurface biosignatures using a suite of instrument techniques including IR reflectance spectroscopy, laser-induced breakdown spectroscopy, and scanning electron microscopy/energy dispersive X-ray spectroscopy. We focus our measurements on subterranean calcium carbonate field samples, whose biosignatures are analogous to those that might be expected on some high-interest astrobiology targets. In this work, we discuss the feasibility and advantages of using each of the aforementioned instrument techniques for the in situ search for biosignatures and present results on the autonomous characterization of biosignatures using multivariate statistical analysis techniques. Key Words: Biosignature suites-Caves-Mars-Life detection. Astrobiology 17, 1203-1218.

Hillslope characterization in terms of geophysical units based on the joint interpretation of electrical resistivity and seismic velocity data

NASA Astrophysics Data System (ADS)

Feskova, Tatiana; Dietrich, Peter

2015-04-01

Hydrological conditions in a catchment depend on many factors such as climatic, geological, geomorphological, biological and human, which interact with each other and influence water balance in a catchment. This interaction leads to the subordination in the landscape structure, namely the weak elements subordinate to the powerful elements. Thereby, geological and geomorphological factors play an essential role in catchment development and organization. A hillslope consequently can be allocated to one class of the representative units because the important flow processes run at the hillslope. Moreover, a hillslope can be subdivided into stratigraphic subsurface units and significant hillslope areas based on the lithological change of contrasting interfaces. The knowledge of subsurface structures is necessary to understand and predicate complex hydrological processes in a catchment. Geophysical techniques provide a good opportunity to explore the subsurface. A complete geophysical investigation of subsurface in a catchment with difficult environmental conditions never will be achieved because of large time effort in the field, equipment logistic, and ambiguity in the data interpretation. The case study demonstrates how a catchment can be investigated using geophysical methods in an effective manner in terms of characterization of representative units with respect to a functional role in the catchment. This case study aims to develop combined resistivity and seismic velocity hillslope subsurface models for the distinction of representative functional units. In order to identify the contrasting interfaces of the hillslope, to localize significant hillslope areas, and to address the ambiguity in the geophysical data interpretation, the case study combined resistivity surveys (vertical electrical soundings and electrical resistivity tomography) with refraction seismic method, and conducted these measurements at one single profile along the hillslope transect and perpendicular to this transect. The measurements along the hillslope transect deliver the two-dimensional hillslope section of resistivity and seismic velocity distribution with contrasting stratigraphic interfaces, whereas the measurements perpendicular to the hillslope transect obtained from vertical electrical soundings survey localize significant hillslope areas indicating existence of two-dimensional features in the subsurface. To demonstrate the suitability of the suggested approach, resistivity and refraction seismic measurements were carried out at the forested gently inclined hillslope in the Weierbach catchment, which belongs to the hydrological observatory Attert Basin locating in the mid-western part of the Grand-Duchy of Luxembourg. This hillslope is characterized by Pleistocene periglacial slope deposits, which plays an important role in the ecosystem functioning. The obtained resistivity and seismic hillslope models of the Weierbech catchment complement well one another. The hillslope models identify three significant hillslope areas along the hillslope called as elementary functional units, and four electrical vertical stratigraphic units and two seismic vertical stratigraphic units that agree with lithological stratigraphy of this study site. In conclusions, the suggested geophysical approach is suitable to characterise a hillslope as the representative unit only at a single transect in the efficient manner in contrast to the expensive 3D-measurements.

Aseptically Sampled Organics in Subsurface Rocks From the Mars Analog Rio Tinto Experiment: An Analog For The Search for Deep Subsurface Life on Mars.}

NASA Astrophysics Data System (ADS)

Bonaccorsi, R.; Stoker, C. R.

2005-12-01

The subsurface is the key environment for searching for life on planets lacking surface life. Subsurface ecosystems are of great relevance to astrobiology including the search for past/present life on Mars. The surface of Mars has conditions preventing current life but the subsurface might preserve organics and even host some life [1]. The Mars-Analog-Rio-Tinto-Experiment (MARTE) is performing a simulation of a Mars drilling experiment. This comprises conventional and robotic drilling of cores in a volcanically-hosted-massive-pyrite deposit [2] from the Iberian Pyritic Belt (IBP) and life detection experiments applying anti-contamination protocols (e.g., ATP Luminometry assay). The RT is considered an important analog of the Sinus Meridiani site on Mars and an ideal model analog for a deep subsurface Martian environment. Former results from MARTE suggest the existence of a relatively complex subsurface life including aerobic and anaerobic chemoautotrophs and strict anaerobic methanogens sustained by Fe and S minerals in anoxic conditions. A key requirement for the analysis of a subsurface sample on Mars is a set of simple tests that can help determine if the sample contains organic material of biological origin, and its potential for retaining definitive biosignatures. We report here on the presence of bulk organic matter Corg (0.03-0.05 Wt%), and Ntot (0.01-0.04 Wt%) and amount of measured ATP (Lightning MVP, Biocontrol) in weathered rocks (tuffs, gossan, pyrite stockwork from Borehole #8; >166m). This provides key insight on the type of trophic system sustaining the subsurface biosphere (i.e., heterotrophs vs. autotrophs) at RT. ATP data (Relative-Luminosity-Units, RLU) provide information on possible contamination and distribution of viable biomass with core depth (BH#8, and BH#7, ~3m). Avg. 153 RLU, i.e., surface vs. center of core, suggest that cleaness/sterility can be maintained when using a simple sterile protocol under field conditions. Results from this research will support future drilling mission planned on Mars. [1] Boston, P.J., et al., 1992. Icarus 95,300-308; [2] Leistel et al., 1998.

DNA-labeled micro- and nanoparticles: a new approach to study contaminant transport in the subsurface

NASA Astrophysics Data System (ADS)

McNew, C.; Wang, C.; Kocis, T. N.; Murphy, N. P.; Dahlke, H. E.

2017-12-01

Though our understanding of contaminant behavior in the subsurface has improved, our ability to measure and predict complex contaminant transport pathways at hillslope to watershed scales is still lacking. By utilizing bio-molecular nanotechnology developed for nano-medicines and drug delivery, we are able to produce DNA-labeled micro- and nanoparticles for use in a myriad of environmental systems. Control of the fabrication procedure allows us to produce particles of custom size, charge, and surface functionality to mimic the transport properties of the particulate contaminant or colloid of interest. The use of custom sequenced DNA allows for the fabrication of an enormous number of unique particle labels (approximately 1.61 x 1060 unique sequences) and the ability to discern between varied spatial and temporal applications, or the transport effect of varied particle size, charge, or surface properties. To date, this technology has been utilized to study contaminant transport from lab to field scales, including surface and open channel flow applications, transport in porous media, soil retention, and even subglacial flow pathways. Here, we present the technology for production and detection of the DNA-labeled particles along with the results from a current hillslope study at the Sierra Foothills Research and Extension Center (SFREC). This field study utilizes spatial and temporal variations in DNA-labeled particle applications to identify subsurface pollutant transport pathways through the four distinct soil horizons present at the SFREC site. Results from this and previous studies highlight the tremendous potential of the DNA-labeled particle technology for studying contaminant transport through the subsurface.

Active Marine Subsurface Bacterial Population Composition in Low Organic Carbon Environments from IODP Expedition 320

NASA Astrophysics Data System (ADS)

Shepard, A.; Reese, B. K.; Mills, H. J.; IODP Expedition 320 Shipboard Science Party

2011-12-01

The marine subsurface environment contains abundant and active microorganisms. These microbial populations are considered integral players in the marine subsurface biogeochemical system with significance in global geochemical cycles and reservoirs. However, variations in microbial community structure, activity and function associated with the wide-ranging sedimentary and geochemical environments found globally have not been fully resolved. Integrated Ocean Drilling Program Expedition 320 recovered sediments from site U1332. Two sampling depths were selected for analysis that spanned differing lithological units in the sediment core. Sediments were composed of mostly clay with zeolite minerals at 8 meters below sea floor (mbsf). At 27 mbsf, sediments were composed of alternating clayey radiolarian ooze and nannofossil ooze. The concentration of SO42- had little variability throughout the core and the concentration of Fe2+ remained close to, or below, detection limits (0.4 μM). Total organic carbon content ranged from a low of 0.03 wt% to a high of 0.07 wt% between 6 and 30 mbsf providing an opportunity to evaluate marine subsurface microbial communities under extreme electron donor limiting conditions. The metabolically active fraction of the bacterial population was isolated by the extraction and amplification of 16S ribosomal RNA. Pyrosequencing of 16S rRNA transcripts and subsequent bioinformatic analyses provided a robust data set (15,931 total classified sequences) to characterize the community at a high resolution. As observed in other subsurface environments, the overall diversity of active bacterial populations decreased with depth. The population shifted from a diverse but evenly distributed community at approximately 8 mbsf to a Firmicutes dominated population at 27 mbsf (80% of sequences). A total of 95% of the sequences at 27 mbsf were grouped into three genera: Lactobacillus (phylum Firmicutes) at 80% of the total sequences, Marinobacter (phylum Proteobacteria) at 8%, and Formosa (phylum Bacteroidetes) at 7%. These lineages support a paradigm suggesting the importance of fermentation in the subsurface. However, this study extends the predicted range for fermentation below the shallow subsurface and into organic carbon limited marine sediments. Other previously characterized subsurface active populations from environments with higher organic carbon concentrations do not show similar levels of reduced diversity or predominance of fermentative populations. This study further emphasizes the spatial variability of microbial populations in the deep subsurface and highlights the need for continued exploration.

Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms

NASA Technical Reports Server (NTRS)

Mahaffy, P. R.; Atreya, S. A.; Fairbrother, D. A.; Farrell, W. M.; Gorevan, S.; Jones, J.; Mitrofanov, I.; Scott, J.

2003-01-01

Montgolfiere balloons can provide a unique near-surface platform for an extended traverse over the polar regions of Mars. During the polar summer, such solar powered balloons would remain in the constant sun of the polar summer and could remain airborne for many weeks or even months as the atmospheric circulation would drive the balloons around the polar region many times before the balloon would cross the terminator. Such a platform for scientific measurements could provide in situ sampling of the atmosphere for trace disequilibrium species that might be indicators of present geological or biological activity in this region. It could furthermore provide high resolution imaging, deep electromagnetic (EM) sounding for subsurface stratigraphy and liquid water, and high spatial resolution neutron measurements of subsurface ice. Technologies for robust balloon deployment on entry and controlled encounters with the surface and near subsurface for sample acquisition in otherwise inaccessible regions are presently being studied and developed with support from NASA.

Astrobiology Exploration Strategies for the Mars Polar Regions Using Balloon Platforms

NASA Technical Reports Server (NTRS)

Mahaffy, P. R.; Atreya, S. A.; Fairbrother, D. A.; Farrell, W. M.; Gorevan, S.; Jones, J.; Mitrofanov, I.; Scott, J.

2003-01-01

Montgolfiere balloons can provide a unique near-surface platform for an extended traverse over the polar regions of Mars. During the polar summer, such solar powered balloons would remain in the constant sun of the polar summer and could remain airborne for many weeks or even months as the atmospheric circulation would drive the balloons around the polar region many times before the balloon would cross the terminator. Such a platform for scientific measurements could provide in situ sampling of the atmosphere for trace disequilibrium species that might be indicators of present geological or biological activity in this regon. It could furthermore provide high resolution imaging, deep electromagnetic (EM) sounding for subsurface stratigraphy and liquid water, and high spatial resolution neutron measurements of subsurface ice. Technologies for robust balloon deployment on entry and controlled encounters with the surface and near subsurface for sample acquisition in otherwise inaccessible regions are presently being studied and developed with support from NASA.

Continuous monitoring of the lunar or Martian subsurface using on-board pattern recognition and neural processing of Rover geophysical data

NASA Technical Reports Server (NTRS)

Mcgill, J. W.; Glass, C. E.; Sternberg, B. K.

1990-01-01

The ultimate goal is to create an extraterrestrial unmanned system for subsurface mapping and exploration. Neural networks are to be used to recognize anomalies in the profiles that correspond to potentially exploitable subsurface features. The ground penetrating radar (GPR) techniques are likewise identical. Hence, the preliminary research focus on GPR systems will be directly applicable to seismic systems once such systems can be designed for continuous operation. The original GPR profile may be very complex due to electrical behavior of the background, targets, and antennas, much as the seismic record is made complex by multiple reflections, ghosting, and ringing. Because the format of the GPR data is similar to the format of seismic data, seismic processing software may be applied to GPR data to help enhance the data. A neural network may then be trained to more accurately identify anomalies from the processed record than from the original record.

Satellite Tidal Magnetic Signals Constrain Oceanic Lithosphere-Asthenosphere Boundary Earth Tomography with Tidal Magnetic Signals

NASA Technical Reports Server (NTRS)

Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Chandrasekharan, Manoj; Olsen, Niles

2016-01-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. Here we use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals an Approximately 72 km thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

Satellite tidal magnetic signals constrain oceanic lithosphere-asthenosphere boundary

PubMed Central

Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Manoj, Chandrasekharan; Olsen, Nils

2016-01-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. We use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals a ≈72-km-thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere. PMID:27704045

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoak, T.E.; Decker, A.D.

Mesaverde Group reservoirs in the Piceance Basin, Western Colorado contain a large reservoir base. Attempts to exploit this resource base are stymied by low permeability reservoir conditions. The presence of abundant natural fracture systems throughout this basin, however, does permit economic production. Substantial production is associated with fractured reservoirs in Divide Creek, Piceance Creek, Wolf Creek, White River Dome, Plateau, Shire Gulch, Grand Valley, Parachute and Rulison fields. Successful Piceance Basin gas production requires detailed information about fracture networks and subsurface gas and water distribution in an overall gas-centered basin geometry. Assessment of these three parameters requires an integrated basinmore » analysis incorporating conventional subsurface geology, seismic data, remote sensing imagery analysis, and an analysis of regional tectonics. To delineate the gas-centered basin geometry in the Piceance Basin, a regional cross-section spanning the basin was constructed using hydrocarbon and gamma radiation logs. The resultant hybrid logs were used for stratigraphic correlations in addition to outlining the trans-basin gas-saturated conditions. The magnitude of both pressure gradients (paludal and marine intervals) is greater than can be generated by a hydrodynamic model. To investigate the relationships between structure and production, detailed mapping of the basin (top of the Iles Formation) was used to define subtle subsurface structures that control fractured reservoir development. The most productive fields in the basin possess fractured reservoirs. Detailed studies in the Grand Valley-Parachute-Rulison and Shire Gulch-Plateau fields indicate that zones of maximum structural flexure on kilometer-scale structural features are directly related to areas of enhanced production.« less

Vadose zone dynamics governing snowmelt infiltration and groundwater recharge in a seasonally frozen, semi-arid landscape

NASA Astrophysics Data System (ADS)

Mohammed, A.; LeBlanc, F.; Cey, E. E.; Hayashi, M.

2016-12-01

Snowmelt infiltration and vadose zone fluxes in seasonally frozen soils are strongly affected by meteorological and soil moisture dynamics occurring during the preceding fall and winter, and complex processes controlling soil hydraulic and thermal regimes. In order to predict their effects on hydrologic processes such as run-off generation, groundwater recharge and plant-water availability in cold regions, an improved understanding of the mechanisms governing coupled water and heat fluxes in the unsaturated zone is needed. Field and laboratory studies were conducted to investigate snowmelt infiltration and groundwater recharge through partially frozen ground over a range of climate and soil conditions in the Canadian Prairies. Meteorological and subsurface field measurements at three sites were combined with laboratory infiltration experiments on frozen undisturbed soil-columns to provide insights into the hydraulic and thermal processes governing water movement. Analysis reveals that antecedent moisture content and thermal profiles both strongly affect subsurface dynamics during infiltration of snowmelt. Preferential flow is also a critical parameter, as both thermal and hydraulic responses were observed at depth prior to complete ground thaw in the field; as well as drainage outflow from the frozen soil column experiments under certain conditions. Results indicate that both diffuse (matrix) and preferential (macropore) flow play significant roles in the infiltration and redistribution of snowmelt water under frozen soil conditions, and shallow groundwater recharge. This study highlights the critical subsurface factors and processes that control infiltration and groundwater recharge in these seasonally frozen landscapes.

In situ time-series measurements of subseafloor sediment properties

USGS Publications Warehouse

Wheatcroft, R.A.; Stevens, A.W.; Johnson, R.V.

2007-01-01

The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein. ASP consists of a four-electrode, Wenner-type resistivity probe and a thermistor that log data at 0.1-cm vertical intervals over a 58-cm vertical profile. To avoid resampling the same spot on the seafloor, the probes are moved horizontally within a 20 times 100-cm-2 area in one of three preselected patterns. Memory and power capacities permit sampling at hourly intervals for up to 3-mo duration. The system was tested in a laboratory tank and shown to be able to resolve high-frequency sediment consolidation, as well as changes in sediment roughness. In a field test off the southern coast of France, the system collected resistivity and temperature data at hourly intervals for 16 d. Coupled with environmental data collected on waves, currents, and suspended sediment, the ASP is shown to be useful for understanding temporal evolution of subsurface sediment porosity, although no large depositional or erosional events occurred during the deployment. Following a rapid decrease in bottom-water temperature, the evolution of the subsurface temperature field was consistent with the 1-D thermal diffusion equation coupled with advection in the upper 3-4 cm. Collectively, the laboratory and field tests yielded promising results on time-dependent seabed change.

Defect detection around rebars in concrete using focused ultrasound and reverse time migration.

PubMed

Beniwal, Surendra; Ganguli, Abhijit

2015-09-01

Experimental and numerical investigations have been performed to assess the feasibility of damage detection around rebars in concrete using focused ultrasound and a Reverse Time Migration (RTM) based subsurface imaging algorithm. Since concrete is heterogeneous, an unfocused ultrasonic field will be randomly scattered by the aggregates, thereby masking information about damage(s). A focused ultrasonic field, on the other hand, increases the possibility of detection of an anomaly due to enhanced amplitude of the incident field in the focal region. Further, the RTM based reconstruction using scattered focused field data is capable of creating clear images of the inspected region of interest. Since scattering of a focused field by a damaged rebar differs qualitatively from that of an undamaged rebar, distinct images of damaged and undamaged situations are obtained in the RTM generated images. This is demonstrated with both numerical and experimental investigations. The total scattered field, acquired on the surface of the concrete medium, is used as input for the RTM algorithm to generate the subsurface image that helps to identify the damage. The proposed technique, therefore, has some advantage since knowledge about the undamaged scenario for the concrete medium is not necessary to assess its integrity. Copyright © 2015 Elsevier B.V. All rights reserved.